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The basis for this unorthodox and unproven treatment for lower extremity ischemia lies in the administration of ethylenediaminetetra-acid (EDTA) in the hopes that the calcium present in arteriosclerotic plaque will be extracted, solubilized by this chelating agent, and subsequently excreted, with a consequent reduction in severity of arterial stenoses. Chelation therapy has been recommended by unorthodox practitioners since the 1950s. In its most common form EDTA is administered intravenously by infusion over several hours, on a near-daily basis for a treatment course of weeks or months. The therapy is most often prescribed as part of an overall approach to treatment of arteriosclerosis that invariably includes sound recommendations such as cessation of tobacco use, exercise, weight reduction, and so forth. To date, no evidence has been presented demonstrating effectiveness of this form of therapy for treatment of arteriosclerosis of any site in a controlled trial setting. The results of numerous clinical reports of effectiveness fall within the expected range for the natural history of the conditions being considered. The reasoning behind this approach to therapy is obviously flawed as authorities generally agree that the important events in the generation of atherosclerotic plaques are related to the proliferation of smooth muscle cells and subsequent deposition by them of collagen, proteoglycans and elastic fibers, as well as the accumulation of large amounts of lipid. Calcification is a tertiary event and many significantly occlusive arteriosclerotic plaques contain little or no calcium. In contrast to many questionably effective therapies that at least involve little or no patient risk, chelation therapy with EDTA carries the potential for significant and even fatal complications. Nephrotoxicity that may produce renal failure is a recognized complication of EDTA therapy. In addition, rapid infusion of EDTA may produce severe hypocalcemia, with resultant tetany and cardiac arrhythmias. A possible role for the drug in production of serious autoimmune reactions has been suggested. On the basis of these considerations, statements have been issued by the Medical Letter, The American Medical Association, The American Heart Association, The American College of Physicians, The American Academy of Family Physicians, The American Society for Clinical Pharmacology and Therapeutics, The American College of Cardiology, and The American Osteopathic Association indicating that there currently exists no basis for use of chelation therapy in treatment of arteriosclerotic disease. |