Pneumatic Boot Therapies

Abstracts

• Abu-Own A, Cheatle T, Scurr JH, and Smith PDC: Effects of intermittent pneumatic compression of the foot on the microcirculatory function in arterial disease. Eur J Vasc Surg 7: 488-492, 1993. Abstract: The venous pump of the foot assists blood returning to the heart. The aim of this study was to evaluate the effect of mechanical activation of the foot pump on the microcirculation of the skin in patients with peripheral occlusive arterial disease. Design: single parallel group comparing patients with arterial disease to normal control subjects. Setting: Department of Surgery, the University College and Middlesex Hospital, London, U.K. Subjects and materials: 15 patients with occlusive arterial disease and 15 control subjects. A pneumatic impulse foot pump was applied to the foot. Outcome measures: the Laser Doppler flux (LDF) and transcutaneous oxygen tension (tcPO2 ) were measured on the big toe with the subject supine, before, during and after a 10 min period of foot pumping. The study was repeated with the subject sitting. Results: on sitting there is a fall in LDF and a rise in tcPO2. Application of intermittent pneumatic compression of the foot in the sitting position resulted in an increase in LDF. In patients, the median percentage increase was 57% and the median difference was 82 arbitrary units (AU)(95%CI 60-130, p< 0.001). In controls, the median percentage increase was 66% and the median difference was 124 AU (95%CI 73-275 p < 0.001). There was a corresponding "further" increase in tcPO2 in both groups of subjects. In patients, the median percentage increase was 8%, in controls the median percentage increase was 10% p < 0.01). Conclusion: we conclude that intermittent pneumatic compression of the foot in the dependent position increases. LDF and tcPO2 Comments: The authors used a mini-pump limited to the foot. They did not pump on the diseased areas of the calf and thigh and they pumped but a brief time (10 minutes) and the effect on LDF was brief fading "away within 20s of stopping the foot pump". Here they are reporting on LDF and tcPO2. Allwood (Clin Sc 16:231, 1957) pumped on the lower calf and documented an increase in blood flow in the foot with a plethysmographic method. Loan ( J Appl Physiol 14(3): 411-413, 1959) rhythmically inflated a cuff around the ankle in the seated position and noted an increase in blood flow in the foot by three methods: venous occlusion plethysmography, heat flow and calorimetry. Henry and Winsor (Am Heart J 70:79-88, 1965) pumped from the head of the fibula to the malleoli and documented increased flow in the foot by measuring falloff in counts from injected I131. Gaskell and Parrott (Surg Gyn & Obstet 146:583-592, 1978) pumped on the foot and ankle and documented an increased clearance of 133 Xe from the dorsum of the foot. See Eze, Comerota et al below for more recent work with non-cardiosynchronous calf and foot pumps.
  
  
• Agerskov K, Tofft HP, Jensen FB, Engell HC: External negative thigh pressure. Effect upon blood flow and pressure in the foot in patients with occlusive arterial disease. Dan Med Bull 37:451-4, 1990. We studied the effect of external application of 35-45 mmHg negative pressure around the thigh on toe blood pressure and skin blood flow in nine patients with occlusion of the superficial femoral artery and rest pain/severe intermittent claudication. The systolic toe blood pressure increased from 32 (range 5-70) mmHg before treatment to 57 (42-75) mmHg (p less than 0.05) during negative thigh pressure and 44 (range 10-88) mmHg after treatment. In addition, the gain in toe blood pressure tended to be greater the lower the pre-test toe pressure was, correlation coefficient r = 0.52 (p greater than 0.05). Relative skin blood flow, measured in the first toe interstice by the 133Xe wash-out method, increased by 304 (range 86-767) percent (p less than 0.05) during the test period compared to the mean wash-out rate obtained before and following the test period. Heart rate, systemic blood pressure, skin temperature, serum protein and haematocrit measured during each phase of the study were similar. We conclude that 35-45 mmHg negative pressure around the thigh in patients with occlusion of the superficial femoral artery induce increased blood perfusion in the foot, possibly due to changes in collateral arterial resistance in the thigh. Comments: The suction-pressure boots in use in the 1930's utilized alternating negative pressure and positive pressure in the supine position. An air seal, of course, is necessary in the upper thigh in such boots and the alternation in negative and positive pressure resulted in considerable shear forces at the air seal; the treatment was stressful to both the skin and underlying tissue. Thirty mm Hg is equivalent to about 17 inches of water pressure, about the distance from the aortic valve to the midthigh in the sitting position. Merely by sitting up during therapy with the Circulator Long-Boot, one gains the benefits of gravity and an equivalent of about 30 mm Hg negative pressure. The treatment is well tolerated and no skin breakdown occurs.
  
  
• Alpagut U, Dayioglu E: Importance and advantages of intermittent external pneumatic compression therapy in venous stasis ulceration. Angiology. 56:19-23, 2005. Venous ulcers are seen following postthrombophlebitic syndrome with venous insufficiency and can begin as a result of minor trauma. In this retrospective study the authors examined the value of external intermittent pneumatic compression therapy in chronic venous ulcers. Results in 1,250 patients with postthrombophlebitic syndromes, 235 of these patients with leg ulcers, revealed that this modality of therapy shortens the therapy duration, lowers the total therapy cost, and hastens the return to active life in comparison to the classical therapy with compression stockings and antiaggregant or low-dose oral anticoagulant therapy. In the light of their findings they propose the wider use of this adjuvant therapy.
  
  
• Amsterdam EA, Lee G, Tonkon MJ, DeMaria AN and Mason DT: Noninvasive circulatory assistance by external counterpulsation. Chapter 14 in Advances In Heart Disease, Volume I, Mason DT editor. Grune & Stratton New York, 1977. The duration of applied pressure was approximately 250 msec. In normal subjects diastolic blood pressure was elevated 40-70% and cardiac output increased 15-60% during the treatment. Treatment of angina patients for one hour daily for 5 days resulted in symptomatic improvement in 17 of 21 individuals with definitely improved angiograms in 5 of 11 and equivocally improved angiograms in 4 of the 11 patients undergoing coronary angiography. An increased vascularity was seen in the angiograms.
  
  
• Applebaum RM, Kasliwal R, Tunick PA, Konecky N, Katz ES, Trehan N and Kronzon I: Sequential external counterpulsation increases cerebral and renal blood flow. Am Heart J 133: 611-615, 1997. Abstract: The purpose of this study was to evaluate the effect of sequential external counterpulsation (SECP) on cerebral and renal blood flow. The effect of SECP on carotid and renal artery blood flow was studied in 35 and 18 patients, respectively. With a portable unit, cuffs were applied to the calves and thighs, sequentially inflated with air at the onset of diastole and deflated at the onset of systole. Carotid and renal Duplex studies were performed during intermittent SECP. Diastolic augmentation of carotid and renal artery flow velocity was observed in all patients. The mean carotid flow integral increased by 22% from 27.7 ± 1.8 cm to 33.1 ± 2.3cm (P=0.001). The mean renal artery flow velocity integral increased by 19% from 21 ± 1 cm to 25 ± 1 cm (P=0.0001). With SECP, a new diastolic Doppler flow velocity wave was observed was observed, with an average peak carotid diastolic flow velocity of 56 ± 4 cm/sec and an average peak renal artery diastolic flow velocity of 40 ± 2.5 cm/sec. This diastolic wave was 75% (carotid) and 68% (renal) as high as the systolic wave during SECP. In addition, with SECP the systolic wave increased 6% and 8% in the carotid and renal artery, respectively (P=0.02 and 0.006 respectively). In conclusion, SECP significantly increases carotid and renal blood flow. This noninvasive, harmless treatment may be useful to support patients with decreased cerebral and renal perfusion. Comment: Case 32 on this website demonstrates what these techniques may accomplish in diabetics with chronic renal failure. But is the treatment described in this article harmless? The ECP devices are generally contraindicated in the presence of leg ischemia. Consideration of the standard reactive hyperemia test in the vascular laboratory is helpful in understanding why. A cuff is placed around the upper thigh for a few minutes and released and the time required for the pulse wave to return to the ankle noted. No blood was delivered to the muscles of the thigh and calf during the placement of the cuff and anoxia of these tissues develops. When the cuff is removed in patients with arteriosclerotic lesions, the metabolic needs of the proximal tissues are met before the blood flow reaches more distal tissues. In a normal leg with an open conduit between the thigh and distal pulse, the distal pulse is quickly detected and the metabolic needs of the leg may be met more simultaneously. In the abnormal leg, however, it may take minutes before the distal pulse is detected. The pulse in the normal leg may be likened to a line of balls on a pool table; hitting one end with the Q-ball will knock a single ball off the end of the line of balls. In the normal leg, there is a column of blood from the heart to the groin and from there to the foot. The pulse wave is transmitted through this column of blood. If the leg is compressed with a bag containing pressure higher than the systolic pressure in the leg, the arterial blood is pressed backward towards the heart and the column of blood from the groin to the foot is gone. Restoration of the pulse at the ankle then requires not only meeting the metabolic needs of the proximal tissue but restoration of the column of blood from the groin to the ankle. Especially, in patients with peripheral arteriosclerotic lesions, the column of blood from the groin to the ankle is not continuous and fills slowly. It is apparent that the application of pressure to the leg that is greater than the systolic pressure at some level in the leg may produce distal ischemia. Even if the application of pressure is brief as in the ECP device, ischemia can and is produced in patients with peripheral vascular disease. If the application of pressure is longer, the pressure then blocks inflow of blood while it is applied. Thus, in the situation where a cuff is applied for a few seconds round the calf at a pressure higher than systolic pressure, a few beats are blocked from entering the calf while venous blood may be expressed from the tissue. Release of such a cuff, of course, will be associated with a brief surge of blood down the popliteal artery until it meets the first arterial lesion where it then is not further assisted. In contrast to these situations, the Circulator Boot compresses the leg with diastolic pressure and is so applied that a normally pressurized portion of the leg is included. Inflation of the Circulator Boot does not push blood out of the normally pressurized segment. Each pulse wave is allowed to enter the leg as best it can. The Circulator Boot then provides a compression both expelling the venous blood and providing a driving force to disseminate the arterial blood around the leg (much as one disseminates water around a sponge that it half wet when one squeezes it). If the heart rate is rapid and there is a question as to whether the time for blood inflow is too short, the Circulator Boot heart monitor signals to the operator to switch to 2:1 or 3:1 settings thus allowing one or two extra pulse waves to enter the leg before leg compressions. These timing considerations remain unique to the Circulator Boot systems and allow our successful treatment of ischemic legs. The rapid action of the Circulator Boot systems allows for the elaboration of endothelial factors as mentioned in our library on vascular hormone and clotting factors. Again, as noted below, we show the importance of these considerations in our commentary on the article by Eze AR et al.
  
  
• Blackshear WM, Pescott C, LePain F, Benoit S, Dickstein R, Seifert KB: Influence of sequential pneumatic compression of postoperative venous function. J Vasc Surg 5:432-6, 1987. Venous capacitance decreased from an ambulatory preoperative state (3.19(0.43cc/100 cc tissue) to the postoperative state of complete bedrest (2.08(0.34). Likewise, venous outflow decreased from 87.2(10.6 to 58.1(8.7 cc/100cc of tissue/min. When legs were pumped postoperatively with a sequential pneumatic device, the falloff was significantly less. The authors hypothesized that the improvement in venous function was induced by the direct mechanical effects of pumping on the vessel wall, humoral or neurogenic factors, or a Venturi effect through increased flow velocity in the vena cava.
  
  
• Bolli R, Marbán E: Molecular and cellular mechanisms of myocardial stunning. Physiol Rev 79:609-34, 1999. The past two decades have witnessed an explosive growth of knowledge regarding postischemic myocardial dysfunction or myocardial "stunning." The purpose of this review is to summarize current information regarding the pathophysiology and pathogenesis of this phenomenon. Myocardial stunning should not be regarded as a single entity but rather as a "syndrome" that has been observed in a wide variety of experimental settings, which include the following: 1) stunning after a single, completely reversible episode of regional ischemia in vivo; 2) stunning after multiple, completely reversible episodes of regional ischemia in vivo; 3) stunning after a partly reversible episode of regional ischemia in vivo (subendocardial infarction); 4) stunning after global ischemia in vitro; 5) stunning after global ischemia in vivo; and 6) stunning after exercise-induced ischemia (high-flow ischemia). Whether these settings share a common mechanism is unknown. Although the pathogenesis of myocardial stunning has not been definitively established, the two major hypotheses are that it is caused by the generation of oxygen-derived free radicals (oxyradical hypothesis) and by a transient calcium overload (calcium hypothesis) on reperfusion. The final lesion responsible for the contractile depression appears to be a decreased responsiveness of contractile filaments to calcium. Recent evidence suggests that calcium overload may activate calpains, resulting in selective proteolysis of myofibrils; the time required for resynthesis of damaged proteins would explain in part the delayed recovery of function in stunned myocardium. The oxyradical and calcium hypotheses are not mutually exclusive and are likely to represent different facets of the same pathophysiological cascade. For example, increased free radical formation could cause cellular calcium overload, which would damage the contractile apparatus of the myocytes. Free radical generation could also directly alter contractile filaments in a manner that renders them less responsive to calcium (e.g., oxidation of critical thiol groups). However, it remains unknown whether oxyradicals play a role in all forms of stunning and whether the calcium hypothesis is applicable to stunning in vivo. Nevertheless, it is clear that the lesion responsible for myocardial stunning occurs, at least in part, after reperfusion so that this contractile dysfunction can be viewed, in part, as a form of "reperfusion injury." An important implication of the phenomenon of myocardial stunning is that so-called chronic hibernation may in fact be the result of repetitive episodes of stunning, which have a cumulative effect and cause protracted postischemic dysfunction. A better understanding of myocardial stunning will expand our knowledge of the pathophysiology of myocardial ischemia and provide a rationale for developing new therapeutic strategies designed to prevent postischemic dysfunction in patients.Comments: Postoperative heart surgery disasters are usually treated with the aortic balloon which has a signifiant morbidity (http://www.circulatorboot.com/Newsletter/vol2numb3.html). In our Case 182, the balloon was associated with the development of significant leg ischemia and had to be discontinued. The use of the Circulator Boot not only restored blood flow to both legs but also benefited his heart (http://www.circulatorboot.com/casehistory/case182.html).
  
  
• Bonetti PO, Holmes DR Jr, Lerman A, Barsness GW: Enhanced external counterpulsation for ischemic heart disease: what's behind the curtain? J Am Coll Cardiol 41:1918-25. 2003. Enhanced external counterpulsation (EECP) has been shown to reduce angina and to improve objective measures of myocardial ischemia in patients with refractory angina. Prospective clinical studies and large treatment registries suggest that a course of EECP is associated with prolongation of the time to exercise-induced ST-segment depression and resolution of myocardial perfusion defects, as well as with enhanced exercise tolerance and quality of life. With a growing knowledge base supporting the safety and beneficial clinical effects associated with EECP, this therapy can be considered a valuable treatment option, particularly in patients who have exhausted traditional revascularization methods and yet remain symptomatic despite optimal medical care. However, although the concept of external counterpulsation was introduced almost four decades ago, and despite growing evidence supporting the clinical benefit and safety of this therapeutic modality, little is firmly established regarding the mechanisms responsible for the beneficial effects associated with this technique. Suggested mechanisms contributing to the clinical benefit of EECP include improvement in endothelial function, promotion of coronary collateralization, enhancement of ventricular function, peripheral effects similar to those observed with regular physical exercise, and nonspecific placebo effects. This review summarizes the current evidence for a contribution of these mechanisms to the clinical benefit associated with EECP.
  
  
• Brandjes DP, Buller HR, Heijboer H et al.:Compression stockings reduced the occurrence of post-thrombotic syndrome in proximal DVT. Lancet 349:759-62, 1977. Sized-to-fit, knee-length, graded compression stockings significantly reduced the occurrence of mild-to-moderate and severe post-thrombotic syndrome in patients with a first episode of proximal deep vein thrombosis. All patients had initially been treated with heparin for 5 or more days and then were given warfarin for three months. Comments: Prandroni et al (Ann Intern Med 125:1-7, 1996) remind us that 29% of patients with DVT develop the post-thrombotic syndrome within 8 years. Compression stockings are helpful but care must be exercised in not applying them to DVT patients with concomitant ischemia.
  
  
• Cheung AT, Savino JS, Weiss SJ:Beat-to-beat augmentation of left ventricular function by intraaortic counterpulsation. Anesthesiology 1996 Mar;84(3):545-54. Author's Abstract: BACKGROUND: Measuring the effects of intraaortic balloon counterpulsation (IABP) in single cardiac beats may permit an improved understanding of the physiologic mechanisms by which IABP improves the circulation. The objective of the study was to use trans- esophageal echocardiography in combination with hemodynamic measurements to test the hypothesis that IABP improves global left ventricular systolic function selectively in the IABP-augmented cardiac beats by acutely decreasing left ventricular afterload. METHODS: Twenty-seven studies in which the IABP-to-R wave trigger ratio was serially changed from 1:1, 1:2, 1:4, 0:1 (IABP off) and back to 1:1 were performed in 20 anesthetized cardiac surgical patients during IABP support. Left ventricular short-axis end-diastolic cross-sectional area, end-systolic area, mean end-systolic wall thickness, and ejection time were measured by transesophageal echocardiography at the midpapillary muscle level. Aortic pressure was measured simultaneously from the central lumen of the intraaortic balloon catheter. These measurements were used to calculate the fractional area change, end-systolic meridional wall stress, and heart rate-corrected velocity of circumferential fiber shortening. The echocardiographic and hemodynamic parameters of left ventricular preload, afterload, and systolic function immediately after balloon deflation (IABP-augmented cardiac beats) were compared to the parameters measured during nonaugmented cardiac beats to determine the beat-to-beat effects of IABP on left ventricular function. RESULTS: IABP-augmented cardiac beats had a decreased systolic arterial pressure and end-systolic meridional wall stress and increased diastolic blood pressure, fractional area change, and velocity of circumferential fiber shortening compared to nonaugmented cardiac beats. IABP did not cause significant beat-to-beat changes in heart rate, pulmonary artery diastolic pressure, or central venous pressure. The improvement in left ventricular systolic function associated with IABP-augmented cardiac beats correlated with the decrease in end-systolic meridional wall stress for that cardiac beat. CONCLUSIONS: Beat-to-beat echocardiographic and hemodynamic measurements performed in anesthetized cardiac surgical patients during IABP support demonstrated improved left ventricular systolic function and decreased left ventricular systolic wall stress in the cardiac beats immediately after balloon deflation. The relationship between left ventricular systolic function and left ventricular systolic wall stress during IABP support suggests that afterload reduction was an important mechanism by which IABP instantaneously improved circulatory function in anesthetized cardiac surgical patients. Comments: And these effects are found with the decompression of a small intraaortic balloon. See Dillon 1998 below for similar large effects seen with the decompression of the Circulator Boot.
  
  
• Chleboun GS, Howell JN, Baker HL, Ballard TN, Graham JL, Hallman HL, Perkins LE, Schauss JH and Conatser RR: Intermittent pneumatic compression effect on eccentric exercise-induced swelling, stiffness, and strength loss. Arch Phys Med Rehabil 76:744-749, 1995. Authors conclude that therapy is effective in temporarily decreasing the swelling and stiffness after exercise-induced muscle injury.
  
  
• Delis KT, Nicolaides AN, Wolfe JH, Stansby G: Improving walking ability and ankle brachial pressure indices in symptomatic peripheral vascular disease with intermittent pneumatic foot compression: a prospective controlled study with one-year follow-up. J Vasc Surg 31:650-61, 2000. CONCLUSION: Intermittent pneumatic foot compression used at home for 4.5 months increases claudication distance by over 100%. Associated increases in r-ABI by 18%, p-eABI by 110%, and arterial calf inflow by 36% suggest an improved collateral circulation. Maximum benefit seems to be offered over the initial 3 months. Treatment benefits are maintained 1 year after treatment. A multicenter study is indicated to quantify actual benefits and to demonstrate cost effectiveness.
  
  
• Delis KT, Nicolaides AN, Labropoulos N, Stansby G: The acute effects of intermittent pneumatic foot versus calf versus simultaneous foot and calf compression on popliteal artery hemodynamics: a comparative study. J Vasc Surg 32:284-92, 2000.Irvine Laboratory for Cardiovascular Investigation and Research, Imperial College School of Medicine, Academic Vascular Surgery, St Mary's Hospital, Paddington, United Kingdom.INTRODUCTION: Intermittent pneumatic compression (IPC) is currently being investigated with respect to its effect on distal arterial volume flow in patients with peripheral vascular disease. Recently published data have shown a substantial acute enhancement in arterial calf inflow in response to IPC of the lower limb in both intermittent claudication and leg ischemia. PURPOSE: The aim of the study was to compare the immediate effects of intermittent pneumatic foot (IPC(foot)) versus calf (IPC(calf)) versus simultaneous foot and calf compression (IPC(foot+calf)) on popliteal artery hemodynamics in patients with intermittent claudication (Fontaine II) and in normal subjects, using duplex ultrasonography. For this purpose, 25 limbs of 20 healthy subjects (age range [mean], 51-74 [64] years) and 31 limbs of 25 claudicants (age range [mean], 56-81 [66.5] years; resting ankle-brachial indices, 0.38-0.75 [0.55]) were examined in the sitting position with and without IPC compression. RESULTS: Mean popliteal artery flow in healthy subjects increased by 98.8% on application of IPC(foot), 188% with IPC(calf), and 274% with IPC(foot+calf) (all P <.001). Mean flow in claudicants increased by 58% on application of IPC(foot), 132% with IPC(calf), and 174% with IPC(foot+calf) (all P ><.001). The mean velocity, peak systolic velocity, and end diastolic velocity displayed a pattern of change similar to that for volume flow in both groups. Pulsatility index decreased in both groups on application of IPC; the lowest values were generated with IPC(foot+calf). CONCLUSION: Of the three compression modes investigated, IPC(foot+calf) was the most effective means of acutely augmenting arterial calf inflow in arteriopaths and normals. The significant increase in end diastolic velocity and decrease in pulsatility index indicate that peripheral vasodilatation is the central mechanism in this impulse-related flow augmentation. Prospective trials are indicated to determine the clinical potential of the long-term effects of IPC(foot+calf) in patients with symptomatic peripheral vascular disease.Comments: Porter accompanied the first article (that above this one) with an editorial suggesting these authors were finally showing boots worked. In that article, they merely pumped on the foot. Here they are showing significantly more effect if they pumped on the foot and calf. If they increased their pumping rate and applied pressure in end-diastole, they would then have our Mini-Boot.
  
  
• Delis KT, Knaggs AL: Duration and amplitude decay of acute arterial leg inflow enhancement with intermittent pneumatic leg compression: an insight into the implicated physiologic mechanisms. J Vasc Surg 42(4): 717-25, 2005. PURPOSE: By acutely enhancing the arterial leg inflow, intermittent pneumatic leg compression (IPC) improves the walking ability, arterial hemodynamics, and quality of life of claudicants. We quantified the duration of acute leg inflow enhancement with IPC of the foot (IPC(foot)), calf (IPC(calf)), or both (IPC(foot+calf)) and its amplitude decay in claudicants and controls in relation to the pulsatility index, an estimate of peripheral resistance. These findings are cross-correlated with the features of the three implicated physiologic mechanisms: (1) an increase in the arteriovenous pressure gradient, (2) suspension of peripheral sympathetic autoregulation, and (3) enhanced release of nitric oxide with flow and shear-stress increase. METHODS: Twenty-six limbs of 24 claudicants with superficial femoral artery occlusion or stenoses (>75%) and 24 limbs of 20 healthy controls matched for age and sex, meeting stringent selection criteria, had their popliteal volume flow and pulsating index (peak-to-peak velocity/mean velocity) measured with duplex scanning at rest and upon delivery of IPC. Spectral waveforms were analyzed for 50 seconds after IPC delivery per 5-second segments. The three IPC modes were applied in a true crossover design. Data analysis was performed with the Page, Friedman, Wilcoxon, Mann-Whitney and chi2 tests. RESULTS: The median duration of flow enhancement in claudicants exceeded 50 seconds with IPC(foot), IPC(calf), and IPC(foot+calf) but was shorter (P < .001) in the controls (32.5 to 40 seconds). Among the three IPC modes, the duration of flow enhancement differed (P < .05) only between IPC(foot) and IPC(foot+calf). After reaching its peak within 5 seconds of IPC, flow enhancement decayed at rates decreasing over time (trend, P < .05, Page test), which in both groups were highest at 5 to 20 seconds, moderate at 20 to 35 seconds, and lowest at 35 to 50 seconds (P < .05, Friedman test). Baseline and peak flow with all IPC modes was similar between the two groups. Pulsatility index attenuation in claudicating limbs lasted a median 32.5 seconds with IPC(foot), 37.5 seconds with IPC(calf), and 40 seconds with IPC(foot+calf); duration of pulsatility index attenuation was shorter in the control limbs with IPC(foot) (30 seconds), IPC(calf) (32.5 seconds), or IPC(foot+calf) (35 seconds), yet differences, as well as those among the 3 IPC modes, were not significant. CONCLUSION: Leg inflow enhancement with IPC exceeds 50 seconds in claudicants and lasts 32.5 to 40 seconds in the controls. Peak flow occurs concurrently with maximal pulsatility index attenuation, within 5 seconds of IPC. Irrespective of group or IPC mode, the decay rate (%) of flow enhancement is highest within 5 to 20 seconds of IPC, moderate at 20 to 35 seconds, and lowest at 35 to 50 seconds. Since attenuation in peripheral resistance terminates with the mid time period (20 to 35 seconds) of flow decay, and nitric oxide has a half-life of <7 to 10 seconds, the study's data indicate that all implicated physiologic mechanisms (1, 2, and 3) are likely active immediately after IPC delivery (0 to 20 sec) and all but nitric oxide are effective in the mid time period (20 to 35 seconds). As the pulsatility index has returned to baseline, the late phase of flow enhancement (35 to 50 seconds) could be attributable to the declining arteriovenous pressure gradient alone. Comments: This study is included among our boot articles although the apparatus used is not a boot that covers and treats large portions of the leg but a cuff that compresses the calf and/or foot in pulses considerably slower than the Circulator Boot. Here again we see transient improvements in blood flow versus the long-lasting effects of Circulator Boot therapy.
  
  
• Delis KT, Nicolaides AN: Effect of Intermittent Pneumatic Compression of Foot and Calf on Walking Distance, Hemodynamics, and Quality of Life in Patients With Arterial Claudication. A Prospective Randomized Controlled Study With 1-Year Follow-up. Ann Surg 241: 431-441, 2005. Abstract: Summary Background Data: Perioperative mortality, graft failure, and angioplasty limitations militate against active intervention for claudication. With the exception of exercise programs, conservative treatments yield modest results. Intermittent pneumatic compression [IPC] of the foot used daily for 3 months enhances the walking ability and pressure indices of claudicants. Although IPC applied to the foot and calf together [IPCfoot+calf] is hemodynamically superior to IPC of the foot, its clinical effects in claudicants remain undetermined. Objective: This prospective randomized controlled study evaluates the effects of IPCfoot+calf on the walking ability, peripheral hemodynamics, and quality of life [QOL] in patients with arterial claudication. Methods: Forty-one stable claudicants, meeting stringent inclusion and exclusion criteria, were randomized to receive either IPCfoot+calf and aspirin[75 mg] (Group 1; n = 20), or aspirin[75 mg] alone (Group 2; n = 21), with stratification for diabetes and smoking. Groups matched for age, sex, initial [ICD] and absolute [ACD] claudication distances, pressure indices [ABI], popliteal artery flow, and QOL with the short-form 36 Health Survey Questionnaire (SF-36). IPCfoot+calf (120 mm Hg, inflation 4 seconds × 3 impulses per minute, calf inflate delay 1 second) was used for 5 months, =2.5 hours daily. Both groups were advised to exercise unsupervised. Evaluation of patients, after randomization, included the ICD and ACD, ABI, popliteal artery flow with duplex and QOL* at baseline*, 1/12, 2/12, 3/12, 4/12, 5/12* and 17/12. Logbooks allowed compliance control. Wilcoxon and Mann-Whitney corrected[Bonferroni] tests were used. Results: At 5/12 median ICD, ACD, resting and postexercise ABI had increased by 197%, 212%, 17%, and 64%, respectively, in Group 1 (P < 0.001), but had changed little (P > 0.1) in Group 2; Group 1 had better ICD, ACD, and resting and postexercise ABI (P < 0.01) than Group 2. Inter- and intragroup popliteal flow differences at 5/12 were small (P > 0.1). QOL had improved significantly in Group 1 but not in Group 2; QOL in the former was better (P < 0.01) than in Group 2. QOL in Group 1 was better (P < 0.01) than in Group 2 at 5/12. IPC was complication free. IPC compliance (=2.5 hours/d) was >82% at 1 month and >85% at 3 and 5 months. ABI and walking benefits in Group 1 were maintained a year after cessation of IPC treatment. Conclusions: IPCfoot+calf emerged as an effective, high-compliance, complication-free method for improving the walking ability and pressure indices in stable claudication, with a durable outcome. These changes were associated with a significant improvement in all aspects of QOL evaluated with the SF-36. Despite some limited benefit noted in some individuals, unsupervised exercise had a nonsignificant impact overall.
  
  
• de Simone G, di Lorenzo L, Ferrara LA, Costantino G, Fasano ML, Soro S, Mancini M: Noninvasive assessment of hemodynamic changes during therapy with nitrendipine in arterial hypertension. Jpn Heart J 28:73-84, 1987. Author's abstract: Changes in hemodynamic variables regulating systolic function were examined by M-mode echocardiography in 14 patients with long-duration primary uncomplicated hypertension treated with nitrendipine once daily (20 mg). At the end of treatment (8th week) blood pressure and peripheral resistance were greatly reduced (p less than 0.0001), while the indices of cardiac function (ejection fraction and cardiac index) showed significant increases (p less than 0.01). The variations in ejection fraction were analyzed by multiple linear regression and were mainly influenced by the decrease in end-systolic stress (contribution: 60%). At baseline, despite no radiographic or clinical signs of heart failure, 6 of the studied patients showed impaired systolic function, likely due to the strength of other variables (age, risk factors); in those patients, systolic function was clearly enhanced at the end of treatment, while no change was found in patients with initial normal pump function. Changes in cardiac output were due to a significant increase in heart rate in patients with normal pump function and to improved stroke volume in the others. Left ventricular mass index was slightly reduced (p less than 0.005), primarily because of the reduction in end-diastolic volume (p less than 0.01). When analyzed by the 2 subgroups (with or without impaired systolic function), the left ventricular mass index appeared to be significantly reduced only in those patients with normal basal pump function. This difference was most likely due to the different effects of treatment on end-diastolic volume.Comments: This article is included because, like the article below (Dillon 1998) describing the hemodynamic effects of booting, the importance of diastolic unloading is emphasized.
  
  
• Dillon RS: An end-diastolic air compression boot for circulation augmentation. J Clin Engineering 3:63, 1980. Description of Circulator Boot systems and comparison with other vascular pneumatic boots.
  
  
• Dillon RS: Effect of therapy with pneumatic end-diastolic leg compression boot on peripheral vascular tests and on the clinical course of peripheral vascular disease. Angiology 31:614-638, 1980. The Circulator Boot is a new end-diastolic pneumatic leg compression device. This report describes its effect on 6 normal young people, 8 ambulatory patients with mild peripheral arterial disease, and 21 consecutive patients (of whom 18 were hospitalized) with severe peripheral arterial disease in 25 legs. The courses of 4 patients are discussed in detail. Significant beneficial effects were documented by subcutaneous PO2 levels, pulse volume measurements, ankle blood pressure measurements, and Doppler ultrasound tracings. Twenty-two of the 25 severe legs benefited clinically from therapy. Immediate therapeutic effects from the boot are attributed to decreases in venous pressure, interstitial fluid pressure, vasoconstriction, and viscosity, and to increases in cardiac output, pulse pressure, and fibrinolysis in the treated leg. The long-term beneficial effects of boot therapy may be related to improved collateral flow and to the rechanneling of obstructed vessels. Comments: The baseline ABI was under 0.5 in the dorsalis pedis in 17 legs and in the posterior tibial in 15 legs. Significant improvements were seen in all of the noninvasive vascular tests measured:

  Table 1: Summary of Vascular Tests

  Means +/- Standard Deviations

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  Increases in BP mm Hg	Dorsalis Pedis 43.1+/-11.2 P<0.001	Post. Tibial 32.1+/-11.1 P<0.01
  Increases in ABI	Dorsalis Pedis 31.0+/-8.4 P<0.01	Post. Tibial 23.7+/-8.4 P<0.02
  Increases in Doppler Amplitudes	Dorsalis Pedis 10.8+/-2.1 P<0.001	Post. Tibial 13.7+/-2.7 P<0.001
  Increases in Ankle Oscillometry Indices	0.8+/-0.12 P<0.001) -	-
  Number of Treatments	47.7+/-43.7	-
  Duration of Treatments	5.8+/-6.6weeks	-

  ---

  The patients were treated as long as needed to address successfully their clinical problems. The effects of a single treatment on the baseline PO2 levels were also reported; persentages of 26 (in relatively normal skin) to 1800% (in obviously ischemic skin) were seen. As serial angiograms posed significant risks to the patients, they were only done in occasional patients; some of these angiograms are shown in our case history section. The equipment and techniques have been subsequently improved. Osteomyelitis was not always easily cured with systemic antibiotics and boot alone. As noted below the addition of locally injected antibiotics proved beneficial (Dillon, 1986).
  
  
• Dillon RS: Treatment of resistant venous stasis ulcers and dermatitis with the end-diastolic pneumatic compression boot (TM). Angiology 37: 47-56, 1986. Abstract: The end-diastolic pneumatic compression boot was used to treat 17 patients with difficult or refractory stasis dermatitis and ulcers. Decreases in induration, pigmentation, and palpable thrombi were observed and all patients were improved or healed. The boot treatment allowed effective local administration of antibiotics on gauze wrappings. Removal of the latter after treatments provided a means of nonsurgical debridement. Healing was maintained by periodic outpatient boot treatments in patients with close follow-up. Ulcers recurred in patients lost to follow-up but again responded to boot treatment. One diabetic man with knee contractures and both severe venous and arterial disease relapsed repetitively and lost both legs in spite of bilateral femoral-popliteal bypasses and his boot treatments. Comments: Venous stasis ulcers are really ischemic lesions in which the blockage is on the venous side, rather than the arterial side. Booting restores venous blood flow in promoting the dissolution of the venous thrombi and in reducing induration and edema. Arterial vascular tests significantly improved with the boot treatments in the seven patients who had concomitant arterial disease. Pulmonary emboli were not a problem. Care must be taken, however, in being sure that new large clots are not present in the larger veins at the start of therapy.
  
  
• Dillon RS: Successful treatment of osteomyelitis and soft tissue infections in ischemic diabetic legs by antibiotic injections and the end-diastolic pneumatic compression boot. Ann Surg 204: 643-649, 1986. For abstract, see our library on "Cellulitis, Osteomyelitis and Sepsis."
  
  
• Dillon RS: Treatment of osteomyelitis in diabetic foot with systemic and locally-injected antibiotics and the end-diastolic pneumatic compression boot - Case studies. Vasc Surg (Westerminister Press) 24: 682-695, 1990. Abstract:The treatment of 35 patients for 43 episodes of osteomyelitis in the distal lower extremity is summarized and the long-term courses of three patients are illustrated in detail. Systemic antibiotics were used both to help control infection in the foot and to prevent septic emboli. The systemic antibiotics were given by the oral route alone (16 episodes), by the parenteral route alone (4 episodes), or by both oral and parenteral routes (22 episodes). Local foot treatments included injections of antibiotics into the infected areas of the foot, multielectrolyte-antibiotic foot soaks, and the end-diastolic pneumatic compression boot. X-ray evidence of osteomyelitis was found one to four weeks after it was clinically suspected and was associated with an improvement in the clinical status of the foot. Osteomyelitis was not considered an indication for amputation. The osteomyelitis lesions healed and foot structure and function were maintained. Comments: Lost in the editorial process of this manuscript was the fact that these were not selected for this report because of their successful treatment; they were consecutive referrals who were found to have osteomyelitis. Patients with severe ischemia and infection likely present with gangrene. Patients with x-ray changes of osteomyelitis must have sufficient blood flow to allow the serial dissolution and remodeling processes characteristic of osteomyelitis. These patients, hence, do have some blood flow and with the techniques described may almost all be cured. It is to be appreciated, however, that most all these patients had significant ischemia: 26 feet had no palpable pulses, 4 had one palpable pulse while 12 feet had both the dorsalis pedis and posterior tibial palpable. The mean of the ABI in the dorsalis pedis and posterior tibial was under 0.6 in 13 feet and under 0.4 in 6 feet. Sterilization of the drainage, healing of the associated ulcers and normalization of the sed rate point to a success regardless what the x-ray may be showing. Allowed some time (weeks to months), the involved bone may be conserved without surgery. How do other centers fare with such cases? See Armstrong et al for the Texas Wound Classification System in our Epidemiology library; close to 100% of our patients would have had amputations in their institution. How is our success interpreted by some reviewers? Those in the Georgia Medicare system, for example, call us investigational, but they also ignore the success reported at the Mayo Clinic. View original article in Vascular Surgery and/or View 60 cases of osteomyelitis successfully treated by these techniques
  
  
• Dillon RS: Optimizing external cardiac-assist compressions in patients with atrial fibrillation by anticipating the next beat. Angiology 47: 123-129, 1996. Comments: This is a computer analysis of the EKG strips taken from 30 patients with atrial fibrillation. An empirical formula was developed and tested on the computer to significantly improve the efficiency of the Circulator Boot in assisting the hearts of patients with atrial fibrillation. This empirical formula has been incorporated into the monitor of the Circulator Boot systems now in production.
  
  
• Dillon RS: Fifteen years of experience in treating 2177 episodes of foot and leg lesions with the Circulator Boot-Results of treatments with the Circulator Boot.Angiology 48, Number 5, Part 2: S17-S34, 1997. Abstract: Objective: To determine the clinical effectiveness of the end-diastolic pneumatic compression boot and of local antibiotics in treating limb lesions associated with diabetes and peripheral arterial, venous and neuropathic disease. Research Design and methods: Office and hospital data were kept over 15 years on 2177 episodes of leg problems classified by the Wagner method for 1514 legs of 1035 patients largely referred because of failure of standard therapies. The fate of the untreated legs served as a control when possible. Results: Healing or improvement of treated legs was seen above that in the literature in all Wagner categories and was significant (P<0.001) compared to the "control" leg which deteriorated in 38.7% of patients. Significant risk factors against a successful outcome included smoking, inability to walk, increased home distance from the boot center, loss to treatment, hemodialysis, a Wagner 4-5 classification, inoperable iliac occlusions, vascular surgical procedures before or after referral for boot therapy and an aggressive vascular surgeon. Neuropathy allowed successful treatment of lesions nondiabetic patients could not tolerate. Relapse was significantly more frequent in ASO patients with diabetes than without diabetes and in patients with neuropathy than those with ASO. Diabetes did not affect the relapse rate in stasis disease. The overall percentage of legs having major amputations was low: 2.46% for diabetic legs at the initial treatment episode, 1.6% at the time of a relapse and 4.14% after seeking treatment elsewhere. For nondiabetic patients, the respective risks were similar: 2.0%, 1.18% and 2.88%. Comments: This study may be the largest and the longest in the medical literature. It shows that long lasting benefits may result from therapy with the Circulator Boot systems. At medical meetings, our salesmen have been presented with the criticism that the study is a one-man show and that it is uncontrolled and retrospective in nature. In answer to these criticisms, one might make many observations. An one-author study is more likely to be uniform in technique (treatment technique is described in the companion article). The study actually has multiple controls: (a) the patients largely had had "control" or standard therapies and were referred after they had failed; (b) the fate of the good leg served as a control in many and it broke down while the presenting diseased leg healed; (c) reviewers for the insurance companies and Medicare could deny payments if the therapies were not shown to be beneficial and necessary; and (c)the referring physician frequently maintained surveillance of these patients and could have discontinued the boot therapy if they saw no progress. Finally, it should be appreciated that these treatments were accomplished in real life situations: the community hospital, the doctor's office and the nursing home... not in a clinical research ward. The treatment works in real life. Full text of this article
  
  
• Dillon RS: Patient assessment and examples of a method of treatment-Use of the Circulator Boot in peripheral vascular disease. Angiology 48, Number 5, part 2: S35-S58, 1997. Summary: Effective peripheral blood flow is positively related to cardiac output and gravity (part dependent) and inversely related to gravity (part elevated), venous pressure, interstitial fluid pressure, degree of peripheral neuropathy, arteriosclerotic and thrombotic arterial occlusions, and infection. These factors are considered in the operation of the end-diastolic pneumatic boot in the treatment of illustrative patients with lymphedema, venous stasis disease, peripheral arteriosclerosis obliterans, peripheral neuropathy, cellulitis and osteomyelitis and the failing heart. A method of treatment that includes the use of the boot and the injection of local antibiotics is described.Full text of this article
  
  
• Dillon RS: Improved hemodynamics shown by continuous monitoring of electrical impedance during external counterpulsation with the end-diastolic pneumatic boot and improved ambulatory EKG monitoring after 3 weeks of therapy. Angiology 49: 523-535, 1998. Abstract: Six normal subjects and 12 patients with clinical angina and significant ST depressions during baseline ambulatory cardiac monitoring were given a single treatment with the end-diastolic pneumatic compression boot, the Circulator Boot - TM. With the use of continuous electrical impedance measurements, multiple hemodynamic variables were followed in five situations: (1) baseline before pumping; during end-diastolic pumping (2) on both legs after every heartbeat, (3) on one leg after every heartbeat and (4) on both legs on alternate beats; and (5) during pumping on both legs during every systole. Both an increase in venous return and a reduction in afterload likely contributed to significant increases in cardiac output (51.1(33.6%), stroke volume (52.1(35.6%), dZ/dT (72.0(68.1%), cardiac index (51.2(33.8%) and acceleration index (50.7(62.2%) during end-diastolic pumping on both legs after every heartbeat. A crucial role for afterload reduction was implicated by opposite effects on CO, CI, dZ/dT and SV during systolic pumping. Again, reductions (or lack of an increase) in ventricular ejection time and/or the pre-ejection period suggested a decrease in afterload during end-diastolic pumping. Pumping on one leg after every heartbeat and on both legs on alternate heartbeats was also effective but less so. After the initial study, the patients were given 14 additional end-diastolic treatments to both legs over three weeks. A clinical benefit was shown by symptomatic improvement in all patients along with a significant reduction in the amount and duration of the RST abnormalities in their ambulatory heart monitoring (P=0.012). Comments: How does the Circulator Boot work, we are commonly asked. Here we see that it is a significant cardiac-assist device that improves stroke volume, cardiac output and, presumably, coronary blood flow. Patients with advanced heart failure commonly have cyanosis of their fingers and toes which may disappear when heart function improves. In contrast to the aortic balloon, the Circulator Boot does not need specialized individuals to apply it; it may be promptly applied, removed and applied again; it has no vascular complications; it does not block blood flow to the lower body; it assists venous return; it stimulates the elaboration of prostacyclin, nitric oxide and fibrinolysins; and it has superior effects on systemic hemodynamics. Indeed, the aortic balloon commonly changes hemodynamic data little. Prolonged therapy with the Circulator Boot, on the other hand, is more confining. The latter disadvantage may be approached by alternating legs, sedating the patient and/or removing the boot intermittently. It is interesting to consider the physiology of the Circulator Boot historically and to contrast the findings reported here with those of Frank in 1895 and Starling in 1914. Frank noted that an increase in preload increased the force of contractions of the isolated frog heart. Starling utilized a canine heart-lung preparation in which the lungs were artificially ventilated (potentially preventing pulmonary congestion as right atrial filling pressures were increased). While allowing aortic pressure to increase about 5%, he found perhaps a 70% increase in stroke volume after a 53% increase in right atrial filling pressure and provided us with the now classic concept that cardiac output increases to a point as the heart fibers are stretched with increases in ventricular filling (Patterson SW, Piper H, Starling EH: J Physiol 48:465, 1914). Again, he noted increases in stroke volume, albeit less prominent, when ventricular volume was increased by increasing peripheral vascular resistance and aortic blood pressure. Two potentially detrimental effects of his experiment are to be noted, however. First, ventricular dilatation significantly increases the force each heart fiber must exert to obtain a given intraventricular pressure; heart work increases and heart efficiency decreases. Second, coronary artery perfusion occurs predominantly in diastole and increased diastolic ventricular pressures decrease coronary perfusion. While therapy with the Circulator Boot does increase preload, the increase in preload is shown not to be crucial. In contrast to Frank and Starling, Circulator Boot therapy increases stroke volume by decreasing afterload while at the same time decreasing heart work and maintaining or ?increasing coronary perfusion. The clinical implications of these observations are obvious. It is apparent, for example, that the failing patient in intensive care may be better served with Circulator Boot therapy than a fluid challenge.... and that the benefit may be easily documented both rapidly and non-invasively with an electrical impedance monitor
  
  
• Dillon RS: Pathophysiology of diabetic foot lesions and their treatment with the Circulator Boot-TM. Chapter 13 in "The Wound Management Manual" pages 141-211. Bok Y. Lee editor. McGraw-Hill 2005.
  
  
• Eze AR, Comerota AJ, Cisek PL, Holland BS, Kerr RP, Veeramasuneni R and Comerota Jr. A|J: Intermittent calf and foot compression increases lower extremity blood flow. Am J Surg 172:130-135, 1996. Authors' conclusions: Measured in the sitting position, the resting popliteal artery blood flow and foot skin perfusion are greater in patients with SFA occlusion compared to normal volunteers. Following compression, popliteal artery blood flow and skin perfusion increased in both groups, but relatively more in volunteers. Increases in popliteal artery blood flow are significantly higher with calf compression than with foot compression for both groups. A patent SFA allows for additive increases in popliteal artery blood flow with simultaneous foot and calf compression in normal persons, whereas this is not observed in patients. However, the increases in foot skin perfusion in patients with an occluded SFA parallel the increases shown in normal volunteers, with separate and simultaneous foot and calf compression. Comments: Here a 22cm calf cuff and a 12cm foot cuff were used to inflate to a pressure of 120 mm Hg over 0.3 seconds, hold the pressure 10 seconds and then release and remain deflated for 20 seconds. The patients had ABI's in the supine position of 0.55 to 0.75. Hypothesizing a brachial artery pressure of 140 mm Hg, their ankle blood pressures might have varied from 77 to 105 mm Hg. In the sitting position with a vertical calf, the ankle is perhaps 36 inches below the aortic root or 30 inches below it when the foot is on a "low stool" (the top of the calf cuff, of course, is closer to the heart and is less benefited by the following calculations). As 30 inches of water pressure equals 55 mm Hg pressure, the perfusion pressure at the ankle was the sum of the two or 77+55 to 105+55 mm Hg. Thus, 132 to 160 mmHg pressure was opposed by the 120 mm pressure of the inflated cuffs in their study. For most patients in their study, the cuff pressure was not sufficient to either obstruct or reverse arterial inflow; as shown below, the same may not be true for patients with more severe ischemia. Here, the pressure was clearly sufficient to expel a considerable volume of venous blood and, on release of the cuffs, markedly increase the distal arterial/venous gradient.
  
  

  The data below shows what happens, however, when a leg is very ischemic and has a progressive drop in systolic pressure from the groin to the foot, a boot encompassing the leg from the groin to the ankle is used, and the boot is inflated to 55 mm Hg for periods of several seconds. These tracings were obtained from a patient referred to the Bryn Mawr Circulator Boot Clinic after his leg had deteriorated elsewhere after treatments with a boot designed for treating lymphedema and venous stasis. In obtaining this study, a Circulator Boot was utilized setting the delay time to zero and the compression time to one second; in effect the boot continued to compress the leg until the boot switch was manually turned off. The boot, hence, could be alternately inflated and deflated for any desired time period. The graph reads from right to left. A baseline period is followed by a series of compressions and decompressions lasting several seconds each. The subcutaneous PO2 level is seen to progressively drop. The boot was then set to deliver end-diastolic compressions and the PO2 tension is seen to progressively rise. Such measurements are not necessary in clinical practice as improper pumping will produce pain and numbness in the distal extremity. If such pain occurs with end-diastolic pumping, the Circulator Boot is set to allow more arterial inflow by decreasing the compression rate from 1:1 to 1:2 or 1:3.

  Subcutaneous PO2 Changes in an Ischemic Leg as Influenced by End-diastolc Compressions versus Compressions Lasting a Few Seconds

• Filip, John: APWCA Case Study #2: Application of end-diastolic pneumatic compression therapy with the Circulator Boot. Podiatry Management 26(9): 149-159, 2007. No abstract available. Illustrated case report in which lady with advanced lesions of both legs and feet spared bilateral amputations.
  
  
• Filip JR, Dillon RS: Treatment of end-stage "trash feet" with the end-diastolic pneumatic boot. Angiology 59(2):214-9, 2008. This study reassessed the clinical effect of Circulator Boot (CB) therapy in patients with cholesterol embolization syndrome (CES) of the lower extremities. The medical records were reviewed of 27 patients consecutively referred to the Bryn Mawr Wound Care and Vascular Center with CES who had not responded to previous therapies. All patients with CES referred from January 1, 1997, to September 19, 2005, were followed up and included in the study. The alternate therapy offered for most patients at the time of referral was limb amputation. The median age of the patients was 65 years (age range, 46-84 years) at the time of diagnosis. Healing of CES was observed after a median interval of 11 months (range, 3-32 months) following the initiation of CB therapy. The total number of legs treated was 41. Of 41 legs, 33 (81%) were totally healed, 6 (15%) improved, and 2 (5%) were amputated. After an initial period of improvement, one patient died a month later of causes unrelated to CES or CB therapy. Another patient improved and discontinued treatment before he was totally healed. Cholesterol embolization syndrome is seen predominantly in patients following cardiac or vascular procedures but may occur spontaneously. The CB seems to be the only effective noninvasive therapy for CES. Early initiation of therapy is essential to minimize tissue loss and patient discomfort.
  
  
• Fisher CG, Blachut Pa, Salvian AJ, Meek RN and O'Brien PJ: Effectiveness of pneumatic compression devices for the prevention of thromboembolic disease in orthopaedic truama patients: a prospective randomized study of compression alone versus no prophylaxis. J Ortho Trauma 9:1-7, 1995. Sequential leg sleeves cycling at 71 second intervals with each compression lasting 11 seconds...ankle 45mm Hgk, calf 35-40mm Hg, and thigh 25mm Hg. Among patients with hip fractures, TE events occurred in 12% of controls and in 4% of treated patients (P < 0.02). No significant difference in pelvic fracture patients.
  
  
• Gilbart MK, Oglivie-Harris DJ, Broadhurst C and Clarfield M: Anterior tibial compartment pressures during intermittent sequential pneumatic compression therapy.Am J Sports Med 23:769-772, 1995. Abstract: We studied the anterior tibial compartment pressures during the application of a JOBST sequential intermittent pneumatic compression device on 5 healthy human volunteers (10 legs). Intracompartmental pressures were measured using a slit catheter. The measurements of interstitial pressures were increased for approximately 120 seconds during each cycle. Pressure measurements in the inflated pressure sleeve varied less than 10% with the measured anterior compartment pressures during intermittent pneumatic compression therapy. This intermittent pneumatic pressure device may elevate intramuscular pressure significantly above that necessary to render muscle ischemic. However, these periods of pressure elevation are not long enough to produce any significant adverse effects, and the beneficial effects of decreased edema fluid may be safely realized.
  
  
• Ginsberg JS, Brill-Edwards P, Kowalchuk G, Hirsh J: Intermittent compression units for the postphlebitic syndrome. A pilot study. Arch Intern Med 149: 1651-2, 1989. The postphlebitic syndrome is a common affliction with limited therapeutic options. Patients who fail to respond to treatment with graded elastic compression stockings often develop a chronic pain syndrome manifested by intractable pain and swelling. Because lymphedema, a condition also associated with leg pain and swelling, has been successfully treated by intermittent compressive therapy with an extremity pump, we conducted a pilot study of compressive therapy in patients with severe postphlebitic syndrome. All five patients studied had dramatic improvement in symptoms and functional status without side effects. Although a large randomized trial is needed to properly evaluate compressive therapy, it appears to be very effective in selected patients.
  
  
• Goldman BS, Hill TJ, Rosenthal GA, Scully HE, Weisel RD and Baird RJ: Complications associated with use of the intra-aortic balloon pump. Can J Surg 25:153-156, 1982. 299 patients between 1977 and 1979. Overall complication rate of 24.4% . Patients with inoperable ASHD or severe left ventricular dysfunction especially at risk (complications in 47.6%). Vascular complications: aortic dissection 1.3%, perforation 0.3%, bleeding at site 2.3%, femoral or iliac occlusion 1%, thromboembolism 4.3% and limb ischemia 5.4%. Infections developed at the femoral site in 5.7% and systemic infection developed in 2.3%.
  
  
• Gruenes J, Nelson JP et al: An evaluation of the efficacy of the Circulator Boot in altering hemodynamics of the ischemic lower extremity and foot. Midwest Podiatry Conference 2005 (Chicago). Barry University School of Grad Med Sci. Every pumped extremity had increased perfusion after four weeks with an average increase of 43%. Twelve of 13 long term ulcers healed during the study.
  
  
• Han JH, Leung TW, Lam WW et al:: Preliminary Findings of External Counterpulsation for Ischemic Stroke Patient With Large Artery Occlusive Disease. Stroke 39:1340-3, 2008. BACKGROUND AND PURPOSE: We aimed to investigate the feasibility and therapeutic effect of external counterpulsation (ECP) in ischemic stroke. METHODS: The trial was a randomized, crossover, assessment-blinded, proof-of-concept trial. ECP treatment consisted of 35 daily 1-hour sessions. Patients were randomized to either early (ECP weeks 1 to 7 and no ECP weeks 8 to 14) or late group (no ECP weeks 1 to 7 and ECP weeks 8 to 14). Primary outcomes were an overall change in National Institutes of Health Stroke Scale (NIHSS) and cerebral blood flow estimated by color velocity imaging quantification. Secondary outcomes were change in NIHSS, color velocity imaging quantification, favorable functional outcome (modified Rankin scale, 0 to 2), and stroke recurrence at weeks 7 and 14, respectively. RESULTS: Fifty patients were recruited. At week 7, there was a significant change in NIHSS (early 3.5 vs late 1.9; P=0.042). After adjusting for treatment sequence, ECP was associated with a favorable trend of change in NIHSS of 2.1 vs 1.3 for non-ECP (P=0.061). Changes of color velocity imaging quantification were not significant but tended to increase with ECP. At week 14, a favorable functional outcome was found in 100% of early group patients compared to 76% in the late group (P=0.022). CONCLUSIONS: ECP is feasible for ischemic stroke patients with larger artery disease.
  
  
• Henein MY, Das SK, O'Sullivan C, Kakkar VV, Gillbe CE, Gibson DG: Effect of acute alterations in afterload on left ventricular function in patients with combined coronary artery and peripheral vascular disease. Heart 75(2): 151-8, 1966. Abstract: Objective: To assess the effect of acute alterations in afterload by aortoiliac clamping, during peripheral vascular surgery, on left ventricular function. Design: Prospective examination of the left ventricular long axis and transmitral Doppler flow preoperatively and intraoperatively; before aortic clamping, during clamping and 5 min, 15 min, and 5 days after unclamping. Setting: A tertiary referral centre for cardiac and vascular disease equipped with invasive and non-invasive facilities. Patients: 20 patients (11 men; mean (SD) age 61 (8) years) with significant aortoiliac disease and documented coronary artery disease and 21 normal controls of similar age. Results: Preoperatively: long axis function was abnormal compared with that in normal controls. In systole total long axis excursion and peak shortening rate were reduced, onset of shortening delayed, and there was pre-ejection lengthening (P<0.001). In diastole there was abnormal shortening during isovolumic relaxation, delaying the onset of long axis lengthening (P><0.001). Peak lengthening rate was also reduced and A wave excursion increased (P><0.001). Transmitral Doppler showed increased A wave velocity and reduced E/A diastolic flow velocities ratio (P><0.001). Intraoperatively: preclamping results did not differ from those before operation. With clamping the extent of systolic and diastolic abnormalities promptly increased as to a lesser extent did those of transmitral flow velocity, although heart rate and blood pressure did not change significantly. Total long axis excursion and A wave amplitude were more reduced by aortic than iliac clamping, whereas the onset of lengthening was more delayed and the lengthening velocity more reduced with iliac clamping. Some 5 min after unclamping systolic long axis function had already returned towards normal; total excursion increased, as did peak shortening rate, and the onset of shortening became less delayed (P><0.001). In diastole the delayed onset of lengthening regressed, its lengthening velocity increased, and A wave excursion fell (P><0.001). Early diastolic transmitral flow velocity also increased. This improvement in systolic and diastolic long axis function had progressed 15 min after unclamping but showed no further change at 5 days. At 5 days after operation, however, systolic and diastolic measurements had improved compared with those preoperatively. Conclusion: Resting left ventricular long axis function is abnormal in patients with combined coronary artery and peripheral vascular disease. It is unaffected by anesthesia but deteriorates with aortic or iliac clamping, although blood pressure remains unchanged. It promptly improves with unclamping after successful peripheral arterial reconstruction. Thus, even in apparently stable coronary artery disease, resting subendocardial function is labile, showing pronounced alterations with changing after-load, even when arterial pressure itself does not change. Comments: Changes in after-load can rapidly be effected in the Circulator Long-Boot. Setting the Circulator Boot heart monitor to deliver boot compressions during systole increases after-load. Setting the monitor to deliver compressions in diastole and to release the leg in presystole decreases after-load. Similar hemodynamic changes are seen here with clamping the aorta or iliac arteries. See Dillon 1998 above.
  
  
• Ho CK, Sun MP, Au TW, Chiu CS: Pneumatic pump reduces leg wound complications in cardiac patients. Asian Cardiovasc Thorac Ann 14:452-7, 2006. Leg wound complications at the site of vein harvest for coronary artery bypass graft, although infrequent, cause significant morbidity. Pneumatic pressure therapy is valuable in venous and lymphatic diseases, but its usefulness after leg vein harvest has not been determined. A prospective randomized controlled trial was conducted on 200 patients, half of whom had sequential pneumatic leg pump therapy postoperatively. Wound healing, extent of lower limb edema, patient satisfaction, and the financial implications of pneumatic pressure therapy were assessed. In the study group, 71 patients had satisfactory wound healing vs. 23 in the control group. The leg wound infection rate in the study group was 3% vs. 15% in the control group ( p = 0.003). Lower limb edema was significantly reduced in the study group in the early postoperative period ( p < 0.05), and the mean postoperative length of hospital stay was reduced by 2.6 days in patients given pneumatic pressure therapy ( p = 0.003). The sequential pneumatic leg pump is an effective, inexpensive, and convenient device that reduces leg wound complications after coronary artery bypass grafting. Comments: Ascending TEDS, of course, would be contraindicated if edema is associated with ischemia. Therapy with the Circulator Boot may both decrease edema and increase leg perfusion.
  
  
• Kakkos SK, Geroulakos G, Nicolaides AN: Improvement of the walking ability in intermittent claudication due to superficial femoral artery occlusion with supervised exercise and pneumatic foot and calf compression: a randomised controlled trial. Eur J Vasc Endovasc Surg 30:164-75, 2005. OBJECTIVES: To compare the effect of unsupervised exercise, supervised exercise and intermittent pneumatic foot and calf compression (IPC) on the claudication distance, lower limb arterial haemodynamics and quality of life of patients with intermittent claudication. METHODS: Thirty-four eligible patients with stable intermittent claudication were randomised to IPC (n = 13, 3h/d for 6 months), supervised exercise (n = 12, three hourly sessions/week for 6 months) or unsupervised exercise (n = 9). In each patient, initial claudication distance (ICD), absolute claudication distance (ACD), resting ankle brachial pressure index (ABPI), and resting hyperaemic calf arterial inflow were measured before, 6 weeks, 6 months and 1 year after randomisation. Quality of life was assessed with the short form (SF)-36, walking impairment (WIQ) and intermittent claudication questionnaires (ICQ). RESULTS: Compared with unsupervised exercise, both IPC and supervised exercise, increased ICD and ACD, up to 2.83 times. IPC increased arterial inflow (p < 0.05 at 6 weeks) and ABPI. Supervised exercise decreased arterial inflow and increased ABPI (p < 0.05 at 6 months). Unsupervised exercise had no effect on arterial inflow or ABPI. IPC improved significantly the ICQ score and the speed score of the WIQ, while supervised exercise improved the WIQ claudication severity score. At 1 year clinical effectiveness of supervised exercise and IPC was largely preserved. CONCLUSIONS: IPC, by augmenting leg perfusion, achieved improvement in walking distance comparable with supervised exercise. Long-term results in a larger number of patients will provide valuable information on the optimal treatment modality of intermittent claudication.Comments: This article is included not because it describes the use of equipment similar to the Circulator Boot, or because it describes impressive therapeutic results or because it deserves attention because of its size; it does not. Rather, it is included because the Aetna Insurance company quotes it as one of a few articles supporting pneumatic boot therapy in patients with arterial disease. Likely, Aetna was influenced by the title of the article which included the popular terms: "randomized" and "controlled". These patients were described as having claudication in association with disease of the superficial femornal artery. As with Ramaswami et al discussed below, the ArtAssist pneumatic device used inflated to 120 mmHg first a foot cuff and then a second later a calf cuff with a frequency of 3 compressions a minute. Of 151 patients screened for the study, 13 were allocated to the IPC treatments and 9 were available for analysis at six months. 117 were initially excluded to produce a study population with significant claudication free of other conditions (27 lines in their methods section) that might make the study difficult. In patients with calf arterial pressures less than 120 mm Hg, the device potentially blocks and even might reverse arterial inflow into the lower leg while successfully expelling venous blood. In patients in whom the arterial inflow was not reversed, emptying the veins increases the A/V pressure gradient when the pump was deflated. In contrast, Circulator Boot therapy in such patients would have delivered more compressions (either every beat or every other heartbeat), utilized a full leg bag thus treating the thigh also and provided concurrent therapy to the heart.
  
  
• Katz ES, Tunick PA and Kronzon I: Observations of coronary flow augmentation and balloon function during intraaortic balloon counterpulation using transesophageal echocardiography. Am J Cardiol 69: 1635-1639, 1992. ...&Quot; Noninvasively, transesophageal echocardiography"...(TEE)..." has demonstrated efficacy in enabling visualization of the proximal left coronary artery and in recording coronary blood flow velocity"... In 6 studied patients..."Peak diastolic coronary blood flow velocity increased by a mean of 117% (range 62 to 287) during balloon inflation (P=0.002). Furthermore, coronary flow velocity integral increased by a mean of 87% (range 43 to 176; P=0.003)." Balloon function and position also evaluated.
  
  
• Kavros SJ, Delis KT, Turner NS, Voll AE, Liedl DA, Gloviczki P, Rooke TW.: Improving limb salvage in critical ischemia with intermittent pneumatic compression: a controlled study with 18-month follow-up. J Vasc Surg 47(3):543-9,2008. BACKGROUND: Intermittent pneumatic compression (IPC) is an effective method of leg inflow enhancement and amelioration of claudication in patients with peripheral arterial disease. This study evaluated the clinical efficacy of IPC in patients with chronic critical limb ischemia, tissue loss, and nonhealing wounds of the foot after limited foot surgery (toe or transmetatarsal amputation) on whom additional arterial revascularization had been exhausted. METHODS: Performed in a community and multidisciplinary health care clinic (1998 through 2004), this retrospective study comprises 2 groups. Group 1 (IPC group) consisted of 24 consecutive patients, median age 70 years (interquartile range [IQR], 68.7-71.3) years, who received IPC for tissue loss and nonhealing amputation wounds of the foot attributable to critical limb ischemia in addition to wound care. Group 2 (control group) consisted of 24 consecutive patients, median age 69 years (IQR, 65.7-70.3 years), who received wound care for tissue loss and nonhealing amputation wounds of the foot due to critical limb ischemia, without use of IPC. Stringent exclusion criteria applied. Group allocation of patients depended solely on their willingness to undergo IPC therapy. Vascular assessment included determination of the resting ankle-brachial pressure index, transcutaneous oximetry (TcPO(2)), duplex graft surveillance, and foot radiography. Outcome was considered favorable if complete healing and limb salvage occurred, and adverse if the patient had to undergo a below knee amputation subsequent to failure of wound healing. Follow-up was 18 months. Wound care consisted of weekly débridement and biologic dressings. IPC was delivered at an inflation pressure of 85 to 95 mm Hg, applied for 2 seconds with rapid rise (0.2 seconds), 3 cycles per minute; three 2-hourly sessions per day were requested. Compliance was closely monitored. RESULTS: Baseline differences in demography, cardiovascular risk factors (diabetes mellitus, smoking, hypertension, dyslipidemia, renal impairment), and severity of peripheral arterial disease (ankle-brachial indices, TcPO(2), prior arterial reconstruction) were not significant. The types of local foot amputation that occurred in the two groups were not significantly different. In the control group, foot wounds failed to heal in 20 patients (83%) and they underwent a below knee amputation; the remaining four (17%, 95% confidence interval [CI], 0.59%-32.7%) had complete healing and limb salvage. In the IPC group, 14 patients (58%, 95% CI, 37.1%-79.6%) had complete foot wound healing and limb salvage, and 10 (42%) underwent below knee amputation for nonhealing foot wounds. Wound healing and limb salvage were significantly better in the IPC group (P < .01, chi(2)). Compared with the IPC group, the odds ratio of limb loss in the control group was 7.0. On study completion, TcPO(2) on sitting was higher in the IPC group than in the control group (P = .0038). CONCLUSION: IPC used as an adjunct to wound care in patients with chronic critical limb ischemia and nonhealing amputation wounds/tissue loss improves the likelihood of wound healing and limb salvage when established treatment alternatives in current practice are lacking. This controlled study adds to the momentum of IPC clinical efficacy in critical limb ischemia set by previously published case series, compelling the pursuit of large scale multicentric level 1 studies to substantiate its actual clinical role, relative indications, and to enhance our insight into the pertinent physiologic mechanisms.
  
  
• Keith SL, McLaughlin DJ, Anderson FA Jr, Cardullo PA, Jones CE, Rohrer MJ, Cutler BS: Do graduated compression stockings and pneumatic boots have an additive effect on the peak velocity of venous blood flow? Arch Surg 127(6):727-30, 1992. Graduated compression stockings and intermittent pneumatic compression boots reduce the incidence of deep vein thrombosis. Recent studies suggest that the simultaneous use of these devices may have a synergistic prophylactic effect; however, conflicting reports also exist. Using duplex imaging, we analyzed the effect on peak venous velocity in the superficial femoral vein produced by the individual and simultaneous use of graduated compression stockings and intermittent pneumatic compression boots. Normal volunteers and postoperative patients were examined. The use of intermittent pneumatic compression boots significantly increased the peak venous velocity relative to rest, whereas the use of graduated compression stockings did not alter the peak venous velocity. Also, the addition of graduated compression stockings to legs already being treated with intermittent pneumatic compression boots did not produce a further augmentation of peak venous velocity. This study demonstrates that the simultaneous use of graduated compression stockings and intermittent pneumatic compression boots does not produce a synergistic augmentation of peak venous velocity in the superficial femoral vein.
  
  
• Kern MJ, Henry RH, Lembo N, Park RC, Lujan MS, Ferry D and O'Rourke RA: Effects of pulsed external augmentation of diastolic pressure on coronary and systemic hemodynamics in patients with coronary artery disease. Am Heart J 110:727-735, 1985. Fourteen men with coronary heart disease and normal left ventricular function were studied. Peak diastolic blood pressure was augmented to within 5mm Hg of systolic pressure. External counterpulsation increased mean arterial pressure from 108±11 to 114±12 mm Hg (P<0.01) and the diastolic-pressure time index from 440±51 to 498±82 units (P><0.01) with no change in the systolic-pressure time index, absolute coronary sinus or great vein cardiac vein blood flow. External diastolic pressure augmentation did not affect heart rate, right heart hemodynamics, cardiac output, or calculated oxygen oxygen consumption. An unanticipated finding was a greater than or equal to 10% reduction in peak systolic pressure during external diastolic pressure augmentation in 8 of the 14 patients. The increase in the diastolic pressure-time/systolic pressure-time index suggests that subendocardial perfusion may be favorably influenced by diastolic pressure augmentation. Their leg pressure was applied 240 msec after the Q-wave of the EKG and was applied for 340 msec. Doppler studies showed a reversal of flow in the femoral artery.Comments: This is not end-diastolic pumping. For a patient with a pulse rate of 80 for example, the R-R interval would be 750 msec and their leg compression would end 170 msec before the next QRS complex.
  
  
• Knight MTN and Dawson K: Effect of intermittent compression of the arms on deep vein thrombosis in the legs. Lancet 2: 1265, 1976. Arm pumping decreased euglobulin lysis time and was associated with a decrease in leg thrombi.
  
  
• Koch CA: External leg compression in the treatment of vascular disease.Angiology 48, Number 5, Part 2: S3-S15, 1997. Author's summary: In summary, external compression of the limbs is a mode of therapy which has enjoyed a long history in the treatment of venous and arterial disease. Evidence suggests that its beneficial effects are mediated through enhancement of venous and arterial blood flow, promotion of vasodilatation, enhancement of fibrinolysis and, in the case of obstructive arterial disease, promotion of the development of collateral circulation. The utility of external leg compression in the prevention of deep venous thrombosis and in the management of chronic venous stasis disease has been well documented, and it has become an accepted treatment for these disorders. The use of pneumatic compression in the treatment of atherosclerotic peripheral vascular and cardiovascular disease is less widespread and their indications less well defined, though the work of a few investigators in each of these areas show striking benefits of the technique. Further investigation in these areas is warranted. Potential benefits to patients of external limb compression therapy include its noninvasive nature, its ability to be applied in the outpatient setting, and long-term cost savings through possible avoidance of hospitalization and invasive procedures. Comments: The author takes us back to Sir James Murray in 1812 and follows the development of boot therapy over the next 183 years. She is referring to intermittent pneumatic compression boots... not constant pressure stockings or wrappings.
  
  
• Kumbasar SD, Semiz E, Sancaktar O, Yalcinkaya S, Ermis C and Deger N: Concomitant use of intraaortic balloon counterpulsation and streptokinase in acute anterior myocardial infarction. Angiology 50: 465-471, 1999. Authors' summary: Using a prospective, nonrandomized design, the authors sought to determine whether concomitant use of intraaortic balloon counterpulsation (IABP) and streptokinase in acute anterior myocardial infarction (MI) would improve the in-hospital mortality rate and angiographic findings. The study included 45 patients with an acute anterior MI. All patients received intravenous streptokinase. Among these, 25 had concomitant IABP while the remaining 20 had streptokinase alone. All patients underwent cardiac catheterization. Patients treated with IABP had a significantly higher frequency of thrombolysis in myocardial infarction (TIMI) grade 3 flow (n: 11; 44% vs n:1 5%, p<0.05), and there was a trend toward a lower in-hospital mortality rate in the IABP group (n: 0; 0% vs N:3; 15%, p=0.08). The angiographic presence of thrombus image and grade >/= 2 coronary collateral circulation to the infarct-related coronary artery for the IABP and non-IABP groups did not differ significantly. The preliminary results of this study suggest that concomitant use of IABP and streptokinase in acute anterior MI increases the incidence of TIMI grade 3 flow and may have decreased the in-hospital mortality rate without unacceptable rates of vascular or hemorrhagic complications. Comments: Complications of their IABP included bleeding and groin hematomas requiring less than 3 units of blood transfusion in 4 patients, balloon rupture in one patient (another inserted without difficulty) and lower extremity ischemia resolving after removal of the balloon in 2 patients. External counterpulsation, of course, has no complications and can be applied more quickly. See Dillon (1998) above more more discussion on IABP vs external counterpulsation. This article by Kumbasar et al is included hopefully to encourage a similar study with the use of the Circulator Boot.
  
  
• Landis EM and Hitzrot LH: Treatment of peripheral vascular disease by means of suction pressure. Ann Intern Med 3:1, 1935.
  
  
• Labropoulos N, Watson WC, Mansour MA, Kang SS, Littooy FN, Baker WH: Acute effects of intermittent compression on popliteal artery blood flow. Arch Surg 133:1072-5, 1998. Objectives: To investigate the immediate effects of intermittent pneumatic foot and calf compression (IPFCC) on popliteal artery blood flow in symptom-free volunteers and to determine the reproducibility of color flow duplex imaging in the popliteal artery. Results: Including all types of variability, the popliteal artery blood flow varied from 8% to 39% with a mean value of 19%. Since the diameter of the artery was obtained with less than 5% variability, the time average mean velocity was responsible for the high variation in flow. During application of the IPFCC, the popliteal artery blood flow increased significantly in all subjects (P<0.001). The mean increase in flow was 2.4 times baseline values. The diameter of the arteries remained unchanged while the time average velocity increased significantly (P><0.001). This velocity increase was due to marked elevation in the peak systolic and end diastolic velocities and diminution of the reverse-flow component, as well as a prolongation of the forward flow during diastole. After cessation of the pump, flow returned to baseline levels (P=.41). Comments: The authors placed inflatable 22- and 12-cm neoprene cuffs on the dorsum of the foot and the muscle mass of the calf, respectively. Their pump inflated to 120 mm Hg for 3 seconds at 12-second intervals with the foot cuff preceding the calf cuff by 2 seconds. Such timing maximizes venous return with this equipment. This equipment differs from the Circulator Mini-Boot in that (1) it compresses the lower leg at a pressure well above systolic pressure in many ischemic legs; (2) its longer compressions [3 seconds Vs 0.34 seconds for the Mini-Boot] may effectively block arterial inflow during its compression phase; (3) it does not encompass the entire lower leg so that its compressions send a pulse wave both proximally and distally with the distal pulse wave potentially stretching or breaking venous valves; (4) it is not cardiosynchronous; (5) it does not lend itself well to the usage of local antibiotics and foot soaks; (6) the authors offer no data showing that its usage has favorably altered blood flow in ischemic legs.
  
  
• Labropoulos N.1; Wierks C.1; Suffoletto B.1: Intermittent pneumatic compression for the treatment of lower extremity arterial disease: a systematic review. Vascular Medicine 7: 141-148, 2002. Abstract: This study aimed to identify the role of intermittent pneumatic compression in treating peripheral arterial disease and to investigate the types of treatment programs that are most effective. Data was sourced from English-language articles which were identified by a computer search using MEDLINE from 1966 to 2001, followed by extensive bibliography review. Studies were included if they contained pertinent material involving a compression device and arterial flow dynamics in lower limbs. A total of 26 English-language studies were identified that met the inclusion criteria. The diverse patient criteria and methods used in the studies provided an opportunity to examine the effectiveness of each, but made it difficult to compare one study with another. To assist in focusing on overall trends in improvement, patient type and treatment type disparities must be identified. In conclusion, it is evident that an intermittent pneumatic compression program appears promising and may be used in patients with severe peripheral arterial disease who are not candidates for revascularization using surgery or percutaneous angioplasty. It is now the goal to establish randomized, prospective, controlled trials to clarify the most beneficial regimen for treating such disease.
  
  
• Labropoulos N, Leon LR, Bhatti A et al: Hemodynamic effects of intermittent pneumatic compression in patients with critical limb ischemia. J Vas Surg 42:710-6, 2005. BACKGROUND: Traditional teaching assumes that the distal arterial tree is maximally dilated in patients with critical limb ischemia (CLI). Endovascular or arterial bypass procedures are the commonly used interventions to increase distal perfusion. However, other forms of treatment such as spinal cord stimulation or intermittent pneumatic compression (IPC) have been shown to improve limb salvage rates. This prospective study was designed to determine if the use of IPC increases popliteal, gastrocnemial, collateral arterial, and skin blood flow in patients with CLI. METHODS: Twenty limbs with CLI in 20 patients (mean age, 74 years) were evaluated with duplex ultrasound scans and laser Doppler fluxmetry in the semi-erect position before, during, and after IPC. One pneumatic cuff was applied on the foot and the other on the calf. The maximum inflation pressure was 120 mm Hg and was applied for 3 seconds at three cycles per minute. All patients had at least two-level disease by arteriography. Fourteen limbs were characterized as inoperable, and six were considered marginal for reconstruction. Flow volumes were measured in the popliteal, medial gastrocnemial, and a genicular collateral artery. Skin blood flux was measured on the dorsum of the foot at the same time. RESULTS: Significant flow increase during the application of IPC was found in all three arteries (18/20 limbs) compared with baseline values (P < .02). The highest change was seen in the popliteal, followed by the gastrocnemial and the collateral artery. After the cessation of IPC, the flow returned to baseline. This was attributed to the elevation of time average velocity, as the diameter of the arteries remained unchanged. The skin blood flux increased significantly as well (P < .03). In the two limbs without an increase in the arterial or skin blood flow, significant popliteal vein reflux was found. Both limbs were amputated shortly after. CONCLUSIONS: IPC increases axial, muscular, collateral, and skin blood flow in patients with CLI and may be beneficial to those who are not candidates for revascularization. Patients with significant venous reflux may not benefit from IPC. This supports the theory that one of the mechanisms by which IPC enhances flow is by increasing the arteriovenous pressure gradient.Comments: These authors are using the same apparatus critiqued above. Here they give some vascular data. In their discussion, they include the long term success of Vella et al (below) inferring the success was obtained with the same IPC apparatus they utilized; not so... Vella et al reported on their usage of the Circulator Boot.
  
  
• Lawson WE, Hui JCK, Soroff HS, Zheng ZS, Kayden DS, Sasvary D, Atkins H and Cohn PF: Efficacy of enhanced external counterpulsation in treatment of angina pectoris. AM J Cardiol 70: 859-862, 1992. Eighteen patients with chronic angina despite medical and surgical RX treated 1 hour daily for 36 hours. All patients improved in symptoms and generally decreased their need for meds. 16 were completely relieved. Serial thallium stress testing showed complete resolution of ischemic defects in 12 patients (67%), reduction in area of ischemia in 2 (11%), and no change in 4 (22%). The exercise duration of max stress testing improved from 8.14+/-0.71 to 9.72+/-77 minutes (P <: 0.005) although the double product did not change significantly. Authors claim that EECP uses thigh balloons and sequenced balloon inflation thus improving their diastolic augmentation over previously available methods. Exclusion criteria included clinical CHF*, aortic insufficiency, recent myocardial infarction (last 3 months)* significant ventricular ectopy* or atrial fibrillation, nonischemic cardiomyopathy*, severe occlusive peripheral vascular disease*, recurrent deep vein thrombophlebitis*, systemic hypertension, and a bleeding diathesis. Comments: * Items have not been contraindications for therapy with the Circulator Boot.
  
  
• Lawson WE, Hui JC, Zheng ZS, Oster Z, Katz JP, Diggs P, Burger L, Cohn CD, Soroff HS and Cohn PF: Three-year sustained benefit from enhanced external counterpulsation in chronic angina pectoris. Am J Cardiology 75:840-841, 1995. Exclusion criteria similar to study above. Follow-up of 18 patients with positive thallium stress tests who were given 36 hours of EECP. Studied within a week after the treatment, 11 patients no longer had evidence of ischemia with the same cardiac workload, three had less ischemia and four were unchanged. Over the next three years, 8 patients received supplemental EECP. At the three yar follow-up, 8 of the 14 patients with initial improvement remained negative, one was lost to follow-up, one refused follow-up stress testing, two had reverted to positive tests, one had a myocardial infarction and one had a coronary bypass graft (CABG). Of the four with ischemia before and after their initial EECP, two had continued abnormal tests, one had PTCA and one had CABG. Comments: It is interesting to note the qualification about no ischemia at the same cardiac workload. We commonly find less angina in our patients treated with the Circulator Boot at the same walking distance.... but as their claudication improves, their walking distance and walking speed may increase still producing angina at the greater cardiac workload.
  
  
• Lawson WE, Hui JCK, Zheng ZS, Burger L, Jiang L, Lillis O, Soroff HS and Cohn PF: Can angiographic findings predict which coronary patients will benefit from enhanced external counterpulsation? Am J Cardiol 77:1107-1109, 1996. This study evaluated and appeared to confirm the hypothesis that a patent vascular conduit was necessary for the efficacy of this treatment via transmission of the augmented diastolic perfusion pressure to the distal coronary artery. The patients were given 35 hours of EECP treatment as five hours a week over seven weeks. Perfusion defects improved in 18 of 19 (95%) patients with 1-vessel disease, in 17 of 19 (90%) patients with 2-vessel disease and 5 of 12 (42%) with 3-vessel disease. EECP may offer promise in some patients in whom complete revascularization is not feasible; in such cases, palliative PTCA or CABG may decrease the coronary artery disease extent to residual 1- or 2- vessel disease that might benefit from counterpulsation.
  
  
• Lawson WE, Hui JCK, Zheng ZS, Burger L, Jiang L, Lillis O, Oster Z, Soroff H and Cohn PF: Improved exercise tolerance following enhanced external counterpulsation: cardiac or peripheral effect? Cardiology 87:271-275, 1996. Twenty-two of 27 (81%) patients treated with EECP improved their exercise tolerance and 21 of the 27 improved their radionuclide stress perfusion images. Post-EECP maximum exercise heart rate and blood pressure, while demonstrating a linear relation with exercise duration, did not increase significantly despite the increased exercise duration. This, the authors suggest, may mean that the increase in exercise duration after treatment was due to both an improved myocardial perfusion and altered exercise hemodynamics. EECP thus appears to exert a "training" effect, decreasing peripheral vascular resistance and heart rate response to exercise. Coronary disease patients may improve their exercise tolerance after EECP because of both improved myocardial perfusion and a decrease in cardiac work load. There were 26 men and one woman in the study. The patients received 35 hours of treatment (1-2 hours daily). The increase in exercise duration was highly significant but modest increasing from 7.17 ± 0.53 to 8.84 ± 0.50 minutes. The patients who had an improved perfusion image after treatment had higher exercise durations both before and after treatment than the group as a whole: 7.22 ±0.63 increasing to 9.12 ±0.60 minutes.
  
  
• Lawson WE, Hui JCK, Oster ZH, Zheng ZS, Cabahug C, Katz JP, Dervan JP, Burger L, Jiang L, Soroff HS, Cohn PF:Enhanced external counterpulsation as an adjunct to revascularization in unstable angina. Clin Cardiol 20, 178-180, 1997. Despite intensive risk factor modification, a patient required two surgical coronary revascularizations and seven multivessel angioplasties over a 26 month period, demonstrating recurrent unstable angina and persistent thallium perfusion defects despite revascularization. Post EECP, angina was relieved, thallium defects were resolved, and the patient remained asymptomatic for 36 months.
  
  
• Lippmann HI, Fishman LM, Farrar RH, Bernstein RK and Zybvert PA: Edema control in the management of disabling chronic venous insufficiency. Arch Phys Med Rehabil 75:436-441, 1994. A 15-year retrospective study assessing the biomedical and socioeconomic rationale of edema control in disabling chronic venous insufficiency... 2317 patients... Unna boot used for ulcerations and compression hosiery used for prevention of ulcerations... Approximate overall healing rate 60.9%.... The Unna boot is relatively cheap but does require regular clinic visits for replacement.
  
  
• Liu K, Chen LE, Seaber AV, Urbaniak JR: Influences of inflation rate and duration on vasodilatory effect by intermittent pneumatic compression in distant skeletal muscle. J Orthop Res 17(3):415-20, 1999. Previous study has demonstrated that application of intermittent pneumatic compression on legs can cause vasodilation in distant skeletal muscle at the microcirculation level. This study evaluated the influence of inflation rate and peak-pressure duration on the vasodilatory effects of intermittent pneumatic compression. The cremaster muscles of 50 male rats were exposed and divided into five groups of 10 each. A specially designed intermittent pneumatic-compression device was applied in a medial-lateral fashion to both legs of all rats for 60 minutes, with an inflation rate and peak-pressure duration of 0.5 and 5 seconds, respectively, in group A, 5 and 0 seconds in group B, 5 and 5 seconds in group C, 10 and 0 seconds in group D, and 10 and 5 seconds in group E. Diameters of arterial segments were measured in vessels of three size categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed that the greatest increase in diameter was produced by intermittent pneumatic compression with the shortest inflation rate (0.5 seconds). A moderate increase resulted from compression with an inflation rate of 5 seconds, and no effective vasodilation occurred during compression with the longest inflation rate (10 seconds). When the groups with different inflation rates but the same peak-pressure duration were compared, there was a significant difference between any two groups among groups A, C, and E and between groups B and D. When the groups with different peak-pressure durations but the same inflation rate were compared, compression with a peak-pressure duration of 5 seconds caused a generally similar degree of diameter change as did compression without inflation at peak pressure. The findings suggest that inflation rate plays an important role in the modulation of distant microcirculation induced by intermittent pneumatic compression whereas peak-pressure duration does not significantly influence the vasodilatory effects of the compression. This may be due to the fact that rapid inflation produces a significant increase in shear stress on the vascular wall, which stimulates vascular endothelium to release nitric oxide, causing systemic vasodilation. Comments: The authors went on to show that the vasodilation could be completely blocked by an inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine implying that the production of nitric oxide was involved in the positive influence of intermittent pneumatic compression on circulation (J Orthop Res 17:88-95, 1999 and J Appl Physiol 92(2):559-66, 2002). The Circulator Boot, of course, also applies pressure for a short duration, commonly 0.42 seconds. While pumping on one leg, we have been able to document improved flow in the opposite leg by various techniques. In our case #143 in our case history section, we used NMR spectroscopy. In another case, we noted 100% oxygen by mask significantly raised polarographic subcutaneous PO2 levels faster when the opposite leg was treated in the Circulator Boot. In case #182, we show how pulse volume curves on the arms change with pumping on the legs. Many things happen with Circulator Boot therapy making the mechanism why remote tissue arterial flow increases unclear: cardiac output increases and venous blood and lymph fluid are expressed from the legs increasing volume presumably elsewhere. In this paper, the generation of nitric oxide is implicated and the desirability of rapid pulsations in promoting the effect is seen.
  
  
• Loh PH, Louis AA, Windram J, Rigby AS, Cook J, Hurren S, Nikolay NP, Caplin J, Cleland JG: The immediate and long-term outcome of enhanced external counterpulsation in treatment of chronic stable refractory angina. J Intern Med 259:276-84. 2006. BACKGROUND: Treatment of angina recalcitrant to conventional pharmacological therapy and revascularization remains problematic. Safe, effective and affordable treatments with high patient acceptability are desirable. Enhanced external counterpulsation (EECP) may fulfil these criteria better than many other proposed interventions. OBJECTIVE: To examine the immediate and long-term effect of EECP in treatment of chronic stable refractory angina. DESIGN: Prospective observational study of consecutive patients treated with EECP and follow-up for 1 year. SETTING: Teaching hospital. MAIN OUTCOME MEASURES: Canadian Cardiovascular Society (CCS) angina grading, weekly angina frequency and glyceryl trinitrate (GTN) use. RESULTS: Sixty-one patients were treated with EECP and 58 completed a course of treatment. Further analysis is confined to those who completed EECP. About 52% of patients suffered from CCS III and IV angina prior to EECP. Immediately post-EECP, angina improved by at least one CCS class in 86% and by two classes in 59%. At 1-year follow-up, sustained improvement in CCS was observed in 78% of the patients. The median weekly angina frequency and GTN use were significantly reduced immediately after EECP [7 (4-14) vs. 1 (0-4) episodes per week and 7 (2-16) vs. 0 (0-2) times per week respectively, P < 0.0001; data in median (interquartile range)]. The reduction was sustained at 1-year follow-up. In 48 patients, their mean exercise time improved significantly after EECP [301 +/- 130 s vs. 379 +/- 147 s, P < 0.0001]. Major adverse treatment-related events were rare. CONCLUSION: This study shows that for patients who fail to respond to conventional measures, a high proportion gain symptomatic benefit from EECP.
  
  
• Makhoul RG, Cole CW and McCann RL:Vascular complications of the intra-aortic balloon pump: an analysis of 436 patients. The Amer Surgeon 59:564-568, 1993. Indications for balloon therapy: intraoperative pump failure (42%), unstable angina (24%), preoperative prophylaxis (22%), preoperative shock (9%) and postoperative support (3%). Vascular complications occurred in 46 patients (10.6%) with leg ischemia, the problem in 40 of the 46. Only the absence of pedal pulses on admission correlated with an increase in vascular complications. Comments: Therapy with the Circulator Boot has not been associated with any such complications and is more rapidly utilized. We have had no studies to evaluate is function in the above roles.
  
  
• Manchanda A and Soran O: Enhanced external counterpulsation and future directions: step beyond medical management for patients with angina and heart failure. J Am Coll Cardiol 50:1523-31, 2007. Between 25,000 and 75,000 new cases of angina refractory to maximal medical therapy and standard coronary revascularization procedures are diagnosed each year. In addition, heart failure also places an enormous burden on the U.S. health care system, with an estimated economic impact ranging from $20 billion to more than $50 billion per year. The technique of counterpulsation, studied for almost one-half century now, is considered a safe, highly beneficial, low-cost, noninvasive treatment for these angina patients, and now for heart failure patients as well. Recent evidence suggests that enhanced external counterpulsation (EECP) therapy may improve symptoms and decrease long-term morbidity via more than 1 mechanism, including improvement in endothelial function, promotion of collateralization, enhancement of ventricular function, improvement in oxygen consumption (VO2), regression of atherosclerosis, and peripheral training effects similar to exercise. Numerous clinical trials in the last 2 decades have shown EECP therapy to be safe and effective for patients with refractory angina with a clinical response rate averaging 70% to 80%, which is sustained up to 5 years. It is not only safe in patients with coexisting heart failure, but also is shown to improve quality of life and exercise capacity and to improve left ventricular function long-term. Interestingly, EECP therapy has been studied for various potential uses other than heart disease, such as restless leg syndrome, sudden deafness, hepatorenal syndrome, erectile dysfunction, and so on. This review summarizes the current evidence for its use in stable angina and heart failure and its future directions. Comments: The systemic effects of booting are frequently surprising. Our Circulator Boot patients have noted improvement in vision, erectile function and a general sense of well-being.
  
  
• McCulloch JM, Marler KC, Neal MB and Phifer TJ:Intermittent pneumatic compression improves venous ulcer healing. Advances in Wound Care 7:22-26, 1994. Abstract: The effects of intermittent pneumatic compression on the healing rates of ulcers in patients with chronic venous insufficiency were examined in a prospective, controlled study of 22 patients. Patients were randomly assigned to the experimental or the control group. Both groups received local wound care followed by application of an Unna boot. In addition, subjects in the experimental group received intermittent pneumatic compression (IPC) twice weekly for one hour each session. Healing rates were reported in square centimeters per day. Data analysis revealed a mean healing rate of 0.08 cm2 per day for control subjects and 0.15cm2 per day for experimental subjects. Statistical analysis demonstrated the healing rates of the two groups to be statistically different. The results appear to indicate that intermittent compression is beneficial in the management of venous insufficiency ulcers.Comments: Our bias, of course, is that intermittent compression is indicated in all patients with stasis ulcers. Clinicians should compare the effects of the various devices on the market. Note if they restore transcutaneous PO2 levels. Note what happens to the texture and the turgor of the pumped areas. Are they softened and reduced in size or are they left firm with water merely expelled?
  
  
• Montori VM, Kavros SJ, Walsh EE, Rooke TW: Intermittent compression pump for nonhealing wounds in patients with limb ischemia. The Mayo Clinic experience (1998-2000). Int Angiol 21(4):360-6. 2002. BACKGROUND: The aim of this retrospective observational study was to review the use of an intermittent pneumatic compression device on nonhealing wounds in patients with critical limb ischemia at Mayo Clinic Rochester. METHODS: The setting was a community and referral multidisciplinary wound care clinic. The authors analysed 107 patients, median age 73, with critical limb ischemia and active ulcers started using a compression device between 1998 and 2000; 101 patients had lower extremity ulcers, and 25% had a history of amputation, and 64% had diabetes. Of all the wounds, 64% were multifactorial in etiology, and 60% had associated transcutaneous oxygen tension levels below 20 mmHg. Patients were typically asked to use the device at home on the affected limb(s) for 6 hours daily. The main outcome criterion was complete wound healing with limb preservation. RESULTS: The median follow-up after initiation of treatment was 6 months. Complete wound healing with limb preservation was achieved by 40% of patients with TcPO(2) levels below 20 mmHg; by 48% with osteomyelitis or active wound infection; by 46% with diabetes treated with insulin; and by 28% with a previous amputation. Half of all amputations occurred in patients with prior amputations. Seven patients discontinued the device because of pain experienced with its use. CONCLUSIONS: Patients with critical limb ischemia and nonhealing wounds at high risk of amputation can achieve complete wound healing and limb preservation by using an intermittent pneumatic compression device.
  
  
• Morgan RH, Carolan G, Psaila JV, Gardner AMN, Fox RH and Woodcock JP: Arterial flow enhancement by impulse compression. Vasc Surg 25: 8-15, 1991. Abstract: Preliminary observations of rapid relief of ischemic rest pain following application of a foot impulse compression device prompted this study to quantify its immediate effects. Blood flow was calculated by means of a duplex ultrasound imager interfaced with a Doppler spectrum analyzer. Twelve normal subjects and 10 patients with peripheral vascular disease (mean Doppler ankle/brachial systolic pressure index = 0.62 (range 0.33-0.74) were studied. Mean resting blood flow (SD) was not significantly different in the two groups: 55.6 24.0 in normal subjects and 48.3 29.8 in the arteriopaths (p=>0.1). During five minutes of pump application in a 45-degree foot-down position, mean popliteal blood flow increased 93% in the normal group (p < 0.0001) and 84% in peripheral vascular patients (p < 0.03); there was no change in the opposite limb. In 5 normal subjects a "placebo" device produced no significant change in flow (p > 0.1). In 4 patients with vascular disease lying supine, impulse pumping produced no significant change in flow (p > 0.1). It is suggested that the hyperemic effect may be explained by the liberation of endothelial-derived relaxing factor (EDRF), a powerful relaxant of vascular smooth muscle, produced in response to sudden pressure changes (hemodynamic shear-stress) within the venous system. Comments: This device "consisted of a small portable pump and air reservoir that vents rapidly and intermittently into a small pneumatic pad held around the foot by a slipper (or beneath a cast). Inflation time was < 0.4 seconds, inflation pressure was approximately 100 mm Hg with a three second duration; the cycle was 20 seconds." This device is truly a "Mini" device. The Mini-Boot of the Circulator Boot Systems, in contrast compresses the entire leg beneath the knee for 0.34 seconds commonly in end-diastole after every other heartbeat... thus, delivering considerably more energy over a much larger area.
  
  
• Parmley WW, Chatterjee K, Charuzi Y, and Swan HJC:Hemodynamic effects of noninvasive systolic unloading (nitroprusside) and diastolic augmentation (external counterpulsation) in patients with acute myocardial infarction. Am J Cardiology 33: 819, 1974. Cardiac index rose 17%, peak diastolic blood pressure rose 20mm Hg and mean diastolic blood pressure rose 7mm Hg after external counterpulsation. Changes in pulse rate, systemic vascular resistance, right atrial pressure and pulmonary wedge pressure were not significant. Stroke work index rose in the patients who had had myocardial infarctions but not in controls.
  
  
• Pfizenmaier DH 2nd, Kavros SJ, Liedl DA, Cooper LT: Use of intermittent pneumatic compression for treatment of upper extremity vascular ulcers. Angiology 56:417-22, 2005. Ischemic vascular ulcerations of the upper extremities are an uncommon and frequently painful condition most often associated with scleroderma and small vessel inflammatory diseases. Digital amputation has been advocated as primary therapy because of the poor outcome with medical care. Intermittent pneumatic compression (IPC) pump therapy can improve ulcer healing in lower extremity ischemic ulcerations; however, the value of this treatment in upper extremity ischemic ulcerations is not known. This observational pilot study consisted of a consecutive series of 26 patients with 27 upper extremity ischemic vascular ulcers seen at the Mayo Gonda Vascular Center from 1996 to 2003. Inclusion criteria were documented index of ulcer size and follow-up ulcer size and use of the IPC pump as adjunctive wound treatment. Twenty-six of 27 ulcers (96%) healed with the use of the IPC pump. Mean baseline ulcer size was 1.0 cm2 (SD=0.3 cm2) and scleroderma was the underlying disease in 65% (17/26) of cases. Laser Doppler blood flow in the affected digit was 7 flux units (normal greater than 100). The mean ulcer duration before IPC treatment was 31 weeks. The average pump use was 5 hours per day. The mean time to wound healing was 25 weeks. Twenty-five of 26 patients reported an improvement in wound pain with pump use. Intensive IPC pump use is feasible and associated with a high rate of healing in upper extremity ischemic ulcers. A prospective, randomized, sham-controlled study of IPC is needed to determine whether IPC treatment improves wound healing compared to standard medical care. Comments: The patients here should have been pleased with their success. Pumping an average of 5 hours a day, they earned it. The "A" Circulator Boot can also be used to treat upper arm ischemia and has especially found usage in the Bryn Mawr Clinic among diabetic dialysis patients with areas of necrosis in the fingers.
  
  
• Podrid PJ: Redefining the role of antiarrhythmic Drugs. New Engl J Med 340:1910, 1999. First paragraph: "The growing recognition of the potentially harmful effects of antiarrhythmic drugs and the subsequent proof from controlled trials that some of these drugs increase the risk of death in some patients have led to a decline in their use. This change in practice has been fueled by the widespread application of nonpharmacologic therapies, such as implantable defibrillators and radio-frequency catheter ablation, which have now become the dominant types of therapy for many patients with ventricular and supraventricular arrhythmias." Podrid then reviews two other articles in the same journal issue, one describing success with sotalol and the other with the short-acting drug ibutilide. He concludes pointing out that authors did not recommend the routine use of either sotalol or ibutilide, that the drugs should be used when nonpharmacologic methods fail, and that drug therapy is continuing to evolve.Comments: This article is included to take the opportunity to discuss rhythm disturbances and booting. The occurrence of rhythm disturbances in our boot population is common. Patients with advanced peripheral arteriosclerosis obliterans may be expected to have coronary heart disease predisposing them to arrhythmias. The computer in the Circulator Boot monitor attempts to adjust boot decompression to maximize cardiac output in patients with atrial fibrillation (see Dillon, Angiology 1996 above). Still, if the heart is irregular, so are boot compressions and such irregularity is disturbing to both the patient and lay observers. Setting the boot to pump on alternate beats tends to decrease the irregularity. The 2:1 setting becomes a necessity if the heart rate is rapid (over 120); with irregular rates between 90 to 120, the 2:1 setting is desirable. Commonly, we attempt to slow rapid atrial fibrillation with either or both digoxin and a beta-blocker to rates below 80. We have been pleased to find that a modest number of patients may convert to normal sinus rhythm during their boot therapy. It is possible that the improved hemodynamics described above (Dillon, Angiology 1998) play a role. Another opportunity for a study?
  
  
• Ramaswami G, D'Ayala M, Hollier LH et al: Rapid foot and calf compression increases walking distance in patients with intermittent claudication: results of a randomized study. J Vasc Surg 41:794-801, 2005. OBJECTIVE: The aim of our pilot study was to determine the usefulness of rapid, high-pressure, intermittent pneumatic calf and foot compression (IPCFC) in patients with stable intermittent claudication, with reference to the end points of improvement in initial claudication distance (ICD) (distance at which patient feels pain or discomfort in the legs), and improvement in absolute claudication distance (ACD) (distance at which patient stops walking because the pain or discomfort becomes severe). METHODS: Thirty male patients presenting with stable, intermittent claudication (ACD between 50 and 150 meters on treadmill testing at 3.8 km/h, 10 degrees gradient) were recruited into this pilot study from a single center. Fifteen patients were randomized to treatment with IPCFC (applied for 1 hour twice daily in the sitting position) and were also advised to have daily exercise, and 15 patients served as controls, who were advised exercise alone. All patients received aspirin and had resting and postexercise ankle/brachial index (ABI) measured at enrollment along with ICD and ACD on treadmill testing (3.8 km/h, 10 degrees gradient). The mean age, baseline ICD, and ACD of the treatment and control groups were 70.4 +/- 7 years and 70.7 +/- 9 years, 55.8 +/- 15 meters and 68.4 +/- 17 meters, and 86.7 +/- 19 meters and 103.9 +/- 27 meters, respectively. Both groups were equally matched for risk factors, including smoking, type II diabetes mellitus, and hypercholesterolemia. IPCFC was applied. The study protocol included follow-up visits at 1, 2, 3, 4, 6, and 12 months with the ABI, ICD and ACD being measured at every visit. RESULTS: The percent change from baseline for ICD and ACD for each patient visit and the mean +/- standard deviation (SD), standard error (SE), and median were calculated for the control and treatment groups. The percent change from baseline measurements (mean +/- SD) for ICD and ACD in the control group at 4, 6, and 12 months were 2.2 +/- 18 and 2.3 +/- 18, 2.9 +/- 17 and 5.2 +/- 20, and 3.6 +/- 18 and 5.8 +/- 20, respectively. In contrast, the changes in ICD and ACD at 4, 6, and 12 months in the treatment group were 137.1 +/- 128 (P < .01) and 84.3 +/- 82 (P < .01), 140.6 +/- 127 (P < .01) and 96.4 +/- 106 (P = .01), and 150.8 +/- 124 (P <0.01) and 101.2 +/- 104 (P <0.01), respectively. Although the ABI showed a slight increase in the treatment group, these differences were not statistically significant. CONCLUSIONS: The results of this pilot study show that IPCFC improves walking distance in patients with stable intermittent claudication. A significant increase in ICD and ACD was seen at 4 and 6 months of treatment, respectively, and the improvement was sustained at 1 year. The combination of IPCFC with other treatment such as risk-factor modification and daily exercise may prove useful in patients with peripheral arterial occlusive disease. It may be a useful first line of therapy in patients with disabling claudication who are unfit for major reconstructive surgery. Improved walking on long-term follow-up and experience from different centers may establish a role for this treatment modality in the future. Comments: This study is included not because of its size (15 patients in the treatment and control groups) or the success of follow-up (6 treatment and 5 control at one year), rather, it is included because the Aetna Insurance company quotes it as one of a few studies supporting the effectiveness of intermittent compression therapy in the treatment of arterial disease. The treatment group had an average of 140% improvement over their baseline walking distances while the control group changed little. The treatment group was asked to pump two hours a day in the ArtAssist equipment for over six months. The latter inflated around the foot and calf rapidly to 120 mm Hg three times a minute holding the pressure for three seconds each compression or 9 seconds a minute. One must be careful with such an apparatus in patients with advanced ischemia as shown by a reactive hyperemia test requiring one to three minutes before the return of the distal arterial pulses. In such patients, the 120 mm Hg inflation pressure may be sufficient to expel both the arterial and venous columns of blood from the leg and the interval between compressions may not be sufficient to allow the arterial column to be re-established. The Circulator Boot differs, of course, in providing more compressions, in not expelling the arterial column (the bag is placed to include a well-vascularized portion of the leg), in not impeding arterial inflow during systole and in providing concurrent cardiac support. The authors point out that the rapid inflation of their boots may have stimulated the endothelium to generate nitric oxide and prostacyclin. Such factors likely have more local than systemic effects and in their patients would be expected to have effects especially in the calf and foot. In contrast, the Long Circulator Boot would be expected to generate these factors throughout the leg and would further benefit patients with occlusive disease above the knee.
  
  
• Shechter M, Matetzky S, Feinberg MS et al: External counterpulsation therapy improves endothelial function in patients with refractory angina pectoris. J Am Coll Cardiol 42:2096-8, 2003. OBJECTIVES: The goal of this study was to investigate the influence of short-term external counterpulsation (ECP) therapy on flow-mediated dilation (FMD) in patients with coronary artery disease (CAD). BACKGROUND: In patients with CAD, the vascular endothelium is usually impaired and modification or reversal of endothelial dysfunction may significantly enhance treatment. Although ECP therapy reduces angina and improves exercise tolerance in patients with CAD, its short-term effects on FMD in patients with refractory angina pectoris have not yet been described. METHODS: We prospectively assessed endothelial function in 20 consecutive CAD patients (15 males), mean age 68 +/- 11 years, with refractory angina pectoris (Canadian Cardiovascular Society [CCS] angina class III to IV), u