In chelation therapy, chemical solutions are used in an attempt to prevent or reverse cardiovascular problems. By binding tightly to calcium and other minerals, chelating agents are thought to remove such substances from atherosclerotic plaques.
Thousands of Americans have received chelation therapy, and many others are wondering whether this treatment can truly reverse the atherosclerosis that obstructs the blood flow in their arteries. The complications of atherosclerosis depend on which blood vessels are affected. For example, plaques that form in the coronary arteries can cause heart attacks or angina, while obstructions in the blood vessels that nourish the brain can cause stroke. Claudication, blockage in arteries that feed the lower part of the body, can cause pain in the legs.
Chelation's proponents say that it is safer and more effective than the surgical procedures that are sometimes used to remove the atherosclerotic blockages or reroute blood flow around them.
However, chelation therapy is not covered by most third-party payers because the mainstream of medicine believes that this treatment can be risky and offers no benefits.
The word chelation comes form the Greek root chele which means "claw." The original concept of using chelation therapy in patients with atherosclerosis is startling in its simplicity.
The chelating agent used most often for treating atherosclerosis is ethylenediamine tetraacetate - EDTA for short - which was developed in Germany during the 1930s for use in the dye industry. EDTA attaches tightly to several metals, including iron, mercury, copper, lead, zinc, aluminum, and calcium. Soon, medical researchers began to use EDTA to remove these metals from biologic systems, including the human body, in cases of poisoning or exposure to toxins.
Over the next two decades, EDTA became the treatment of choice for lead or arsenic poisoning, and today treatment of lead poisoning remains the only use of EDTA that has been approved by the Food and Drug Administration.
After EDTA has captured the minerals, the kidneys remove both the chelator and the metal bound to it from the body. Since chelation therapy is approved for the treatment of lead poisoning, it can be legally prescribed and performed.
Both the critics and the proponents of chelation therapy have consistently called for randomized, "double-blind" trials. A small research study along these lines was reported in 1994. In this study, a number of patients were recruited from clinics specializing in atherosclerosis in the arteries to the legs. The patients were then randomly assigned to receive infusions with chelating agents or an inactive saline (salt water) solution. The infusions were indistinguishable by container, labeling, or color. Each patient received a total of 20 infusions given over about three hours, twice per week for 10 weeks.
At the end of the study period, there was a significant improvement in the distance the patients could walk in both groups. However, there was no difference between the patients who had received chelation therapy and those who had received saline in terms of the distance they could walk without symptoms. Chelation therapy also did not have any detectable benefit on fatigue, mood, or general quality of life.
The safety of chelation therapy has sometimes been questioned, and it should be noted that there were no significant side effects in either group.
This study does not put the chelation therapy controversy to rest. The number of patients in the study was small and the subjects were studied for only three months. The study did not, however, prove that chelation therapy is worthless and did not indicate that it is dangerous. Yet it did not show the types of dramatic benefits that are sometimes cited by chelation's proponents.
Pending further data, chelation therapy remains of unproven benefit.