Evidence-Based Medicine and Invasive Procedures on Diabetic Foot


There have been many published reports on the results of bypass surgery and angioplasty. Almost without exception the immediate success of the procedure and the duration of the patency of the new vascular channels are described. There are no placebo-controlled prospective studies supporting these procedures in the treatment of the diabetic foot. The authors presume that the reader will accept the hypothesis that legs would have been lost of necessity if the procedures were not accomplished. There are, however, prerequisites for a successful vascular procedure: (a) There must be an inflow of blood to the point where the bypass begins. (b) There must be runoff at the point where the bypass ends. (c) Preferably the saphenous vein of the patient should be available for the bypass. (d) The patient should be healthy enough to tolerate lengthy anesthesia (e.g. no recent myocardial infarction or congestive heart failure etc). (e) The patient should have kidney function capable of tolerating the dye for an accurate arteriogram which functions as "the roadmap" for the surgeon. (f) The patient should have a blood type that the local blood bank can support. (g) The patient should not have heparin antibodies which might interfere with anticoagulation during and after the procedures. (g) Infection should be absent in the operative field. And (h) the surgeon and anesthetist need expert professional technique. Obviously, the healthier the patient is the more likely a procedure will be successful. Conversely, more disease means more difficulty and less success for the surgeon. Again, it is likely that the easier the procedure and the healthier the patient, the better the prognosis of the patient without the procedure. As an aside one might note that the patients historically coming to Circulator Boot Clinics were either not candidates for bypass or had had bypasses which failed.

Patients who do not prosper under the care of physicians at one hospital commonly seek care elsewhere and are lost to follow-up of their physicians. Medicare statistics have the advantage of following patients as they move throughout our health system. Medicare data shows the number of leg amputations per year rose in 18 of the 22 years between 1980 and 2002.

Further, the Medicare data persisted even after correction for age. If the number of amputations had decreased, numerous groups would have claimed a role: the pharmaceutical firms might claim a role for new antibiotics, anti-lipid medications, new insulins, anti-platelet medications etc. The diabetologists might note their interest in normalizing blood glucose levels. And the surgeons, of course, might claim a benefit for vascular surgery. But in spite of many articles suggesting that multi-specialty clinics and various prophylactic programs may be effective in reducing the amputation rate, it is not clear that the rate of leg amputations has receded. Indeed, patients with known risk who should be under especially close scrutiny have not benefited from new techniques. The diabetic who has lost one leg, for example, has the same prognosis for the remaining leg that he/she had 40 years ago. The following articles suggest that we are in need of new therapies and might be reviewed especially by those planning future research in the field.

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