Chelation therapy involves infusing a synthetic amino acid (EDTA) into the veins. EDTA binds to lead, iron, copper, calcium, and other metals in the blood, renders them inactive and causes them to be excreted in urine. Because calcium is often a component of arterial plaque, it has been proposed that EDTA might remove calcium from arterial plaque, thereby improving blood flow in people with coronary artery disease.
As many as 500,000 people in the United States are treated with chelation therapy each year—some for metal poisoning, and others for treatment of peripheral artery disease or coronary artery disease (also called ischemic heart disease). Chelation therapy is FDA-approved for the treatment of metal poisoning, but not for treatment of peripheral or coronary artery disease. A recent study published in the Journal of the American Medical Association found that chelation therapy provided no benefit over placebo in relieving symptoms of ischemic heart disease.
Researchers in Calgary, Alberta, Canada enrolled 84 participants—average age 65 and mostly men—into a study conducted between January 1996 and January 2000. Participants had coronary artery disease proven by angiography or a documented heart attack and stable angina while receiving medical treatment. In addition, all participants had evidence of ischemia (reduction in blood flow due to blockage in the coronary arteries) during a treadmill test. People were excluded from this study for the following reasons: a pending revascularization procedure, previous chelation therapy, inability to walk on a treadmill, evidence of heart failure, resting electrocardiogram (ECG) abnormalities that would interfere with assessment, abnormal kidney or liver function, or untreated lipid abnormalities.
Forty-one participants were randomly assigned to receive infusions of chelation therapy and 43 participants to receive infusions of an inactive placebo solution (salt water). Each participant received infusions twice weekly for the first 15 weeks and once monthly for the following 3 months. Because vitamin and mineral supplements are recommended for people who undergo chelation therapy, participants in both groups took oral multivitamins daily. This was a double-blind study, so neither researchers nor participants knew which participant received which treatment
Treadmill testing was performed at the start of the study and at weeks 15 and 27, in addition to blood, urine, lipid, and fluid tests. Treadmill tests measured how much time elapsed during exercise on the treadmill before a participant experienced ischemia. At the start of the study and at weeks 15 and 27, participants also answered questionnaires about their ability to exercise and their quality of life.
The researchers compared treadmill test results from the start of the study with results at week 27. They also compared the chelation group's treadmill test results at week 27 with those of the placebo group. Finally, they compared quality of life and exercise capacity information from the start of the study with those at week 27 and between the two groups.
By week 27, participants in both groups increased the time spent on the treadmill before experiencing ischemia. On average, people in the chelation group exercised on the treadmill for 63 seconds longer before experiencing ischemia and people in the placebo group exercised for 54 seconds longer. In addition, capacity to exercise and quality of life improved similarly between the two groups.
Although the chelation group experienced a 9-second improvement over the placebo group in time to ischemia, this difference was not statistically significant. This suggests that chelation therapy was no more effective than the placebo in improving the symptoms of ischemia, exercise capacity, or quality of life in people with ischemic heart disease.
There are limitations to this study that are worth noting. The researchers measured the effectiveness of chelation therapy in people with ischemic heart disease who had stable angina and could exercise on a treadmill. In addition, nearly 85% of the participants were men. Therefore, these results may not apply to patients with other types of heart disease or to female patients. The study population of 84 patients is fairly small, and larger studies are needed to confirm these results.
Although some patients with heart disease who undergo chelation therapy report feeling better and having greater exercise tolerance, scientific studies have not concluded that chelation therapy improves the symptoms of heart disease. Previous controlled studies of chelation therapy as treatment for peripheral artery disease also showed no benefit of chelation therapy.
Should you try chelation therapy if you have ischemic heart disease with stable angina? The authors of this study say no. In their opinion, the results of this study and others do not support chelation therapy as an effective method of treating ischemia and improving the quality of life in patients with ischemic heart disease.
Knudtson ML, et al. Chelation therapy for ischemic heart disease. A randomized controlled trial.
Journal of the American Medical Association . January 23/30, 2002;287(4):481-486.
Last reviewed Jan 25, 2002 by Richard Glickman-Simon, MD
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