Chelation Therapy: New Proof of Lack of Efficacy

Chelation therapy for coronary atherosclerosis has been promoted for decades as an alternative treatment to avoid traditional medical and surgical interventions. Such an approach appeals to patients who may be fearful of mainstream medical therapy or who philosophically seek “holistic” care. Chelation therapy, which involves intravenous administration of ethylenediamine tetra-acetic acid (EDTA) in combination with oral minerals and vitamins, has several theoretical mechanisms of possible benefit. These include improving plaque characteristics by removing calcium, inhibiting low-density lipoprotein cholesterol oxidation, diminishing platelet aggregation, and lowering iron stores (increased total body stores of this element are possibly associated with the development of coronary disease). However, scientific evidence to support a benefit from chelation therapy in patients with atherosclerotic disease is lacking. Despite lack of efficacy, treatment of atherosclerotic disease by EDTA infusion is popular. One study1 estimated that 800,000 patient visits for chelation therapy occur annually in the United States. A recent survey of patients in Alberta, Canada who had undergone coronary angiography found that approximately 8% had received chelation treatments.2 The cost of a series of treatments has been estimated at $30003 and is virtually never covered by insurance—a significant financial burden for many individuals. Small, randomized, blinded trials of patients with peripheral disease have not shown a benefit from EDTA infusion.4 Until this year, no such trials involving patients with coronary disease have been performed. Knudtson et al.5 have now conclusively put to rest the notion that chelation therapy will symptomatically benefit coronary patients. Their double-blind, randomized, placebo-controlled trial compared the effects of EDTA vs. placebo infusion on exercise time to ischemia, total exercise capacity, and quality of life scores. No benefit of chelation therapy was found. In this study, 84 patients with documented coronary disease (by angiography or prior myocardial infarction) who had stable angina and exercise electrocardiograms (ECGs) demonstrating ischemia were randomized to receive EDTA or placebo infusion over 3 hours twice weekly for 15 weeks, then once monthly for 3 more months. All received optimal traditional medical therapy and coronary risk reduction as well as oral multivitamin therapy. Exercise ECGs and quality of life questionnaires were administered after 15 and 27 weeks of therapy (approximately at the midpoint and conclusion of the study period). Patients were followed clinically for 1 year and had all clinical cardiac events recorded. At 27 weeks, the mean exercise time to ischemia increased from 589 seconds to 652 seconds (a 63-second improvement) in the chelation group, and from 572 seconds to 626 seconds (a 54-second improvement) in the placebo group. These changes did not differ significantly between groups. Similarly, total exercise capacity increased in both groups, but with no significant differences between groups. Additionally, though quality of life measures changed favorably in both groups, these improvements did not differ significantly. No deaths occurred in either group. One patient in each group had a myocardial infarction. Six placebo patients and nine chelation patients were admitted for worsening angina. Angioplasty was performed in four of the placebo patients and none of the chelation patients. None had bypass surgery during the year of follow-up. The study was not powered to assess differences in these clinical events. Thus, this first randomized, blinded, placebo-controlled study of chelation therapy in stable angina patients failed to demonstrate any significant benefit of EDTA administration on exercise test parameters of ischemia. These data now give clinicians a firm basis to advise patients to avoid both the considerable expense and the delay in proven therapy incurred by choosing chelation.

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