Chelation therapy for heart disease: Medicine, alternative medicine, or quackery?

The Atlantic published an article last month on the use of chelation therapy as a treatment for heart disease. A large study was performed over an approximate 10-year period to test whether chelation therapy could reduce mortality and serious cardiovascular events in patients who had a heart attack (myocardial infarction, MI) at least 6 weeks prior. The results were published last year in The Journal of the American Medical Association (JAMA).

Chelation is the process by which certain compounds can bind metal ions with high affinity by possessing multiple binding interactions. In this manner, a chelator (or chelating agent) can remove metal ions from a solution by binding them all up. This property can have medical benefits because certain heavy metal ions are toxic.

Chelation therapy "involves the administration of chelating agents to remove heavy metals from the body." More specifically, it "is used as a treatment for metal poisoning, including acute mercury, iron (including in cases of thalassemia), arsenic, lead, uranium, plutonium and other forms of toxic metal poisoning."

There are dangers associated with chelation therapy because many other metals (e.g. calcium, magnesium, iron) are essential for life processes (i.e. enzyme cofactors), and if they get stripped away by chelating agents, then these processes may be inhibited. Thus, the amount of chelator must be carefully modulated especially for long-term treatments.

The rationale for using chelation therapy to treat heart disease is that the ion calcium is involved in the formation of atherosclerotic plaques. Calcification contributes to this "hardening of the arteries". Thus, the idea is that a chelator could help remove calcium from the blood vessels and reduce atherosclerosis.

In the JAMA study, the chelating agent was a compound called EDTA. In a randomly-controlled trial, some test subjects were given the EDTA along with vitamins and electrolytes, whereas the control group received a placebo. The overall results bordered on insignificance but certain aspects of the findings could be interpreted as positive (Atlantic):

"People who received chelation after a heart attack had a 26 percent chance of another heart attack (or stroke, or hospitalization for angina, or a procedure like bypass surgery) within the next five years. People who got placebo infusions had a slightly higher risk—30 percent (a difference that’s statistically significant, but barely). Among patients with diabetes, the result was more impressive: chelation reduced deaths in diabetic heart-attack survivors by 43 percent over five years. But this subset of patients was small. And an unusually high number of people had dropped out of the study."

On the positive side, there was the impressive reduction in deaths for diabetic heart-attack survivors. On the negative side, some researchers have questioned the quality of the data "highlighting the fact that more than half of the clinics in the study practiced alternative medicine, and some offered notoriously unscientific treatments." Indeed, Dr. Steven Nissen, the chairman for cardiovascular medicine at the Cleveland Clinic, called the study "a dangerous failure" and did not mince words in his criticism:

'Nissen had perused the Web sites of the clinics involved in the trial, and was appalled. “They offer every bizarre treatment possible,” he told me, from stem-cell therapy for growing breasts, to treating diabetes with cinnamon. “They’re warning people not to get immunized. These are the same people that are going to be doing a high-quality scientific trial? You gotta be kidding.” Nissen is adamant that Lamas’s study will be seen as an endorsement of chelation and will lead to a public-health “catastrophe.”'

Other scientists have raised additional concerns relating to the fact that the EDTA was administered with "supplements" (Harvard Health Blog) which complicated interpretation of the results:

“The reason why we’re so uncertain about what to conclude is this chelation mixture had many components to it. It wasn’t just chelating agents,” says Dr. Elliott Antman, professor of medicine and Associate Dean for Clinical/Translational Research at Harvard Medical School. In addition to the main chelating chemical, EDTA, the infused solution contained vitamins, magnesium chloride, potassium chloride, and a cocktail of other ingredients. “We don’t know which of these components is contributing to the results,” he says.

And so despite this large study, the debate goes on. The lead researcher Dr. Gervasio Lamas is planning another study that focuses on heart attack survivors who are diabetic (i.e. group with the biggest effect). In the meantime he will offer chelation therapy at his own hospital as a treatment for heart disease.

It is important to emphasize that there are less controversial, medically proven methods for reducing your cardiovascular risk. Most notably, one can attempt to live a healthier lifestyle and follow Life's Simple 7 rules.

Figure 1. Many doctors are skeptical of the "Chelation Miracle".