Chelation Therapy's Mettle to Be Tested
Blood-cleansing technique to get first large-scale clinical trial as heart aid
MONDAY, Aug. 12, 2002 (HealthDayNews) -- Much like tattoos and body piercing, chelation therapy may be poised to move from the margins of medicine into the mainstream.
The National Center for Complementary and Alternative Medicine and the National Heart, Lung, and Blood Institute, both part of the National Institutes of Health (NIH), are launching the first large-scale clinical trial to see if chelation therapy is a safe and effective treatment for people with coronary artery disease, the leading cause of death for both men and women in the United States.
Chelation therapy was originally developed in the 1930s to combat heavy metals such as arsenic, which were expected to be used in chemical warfare. Patients receive EDTA (ethylene diamine tetra-acetic acid), a synthetic amino acid, intravenously. The EDTA then binds to the molecules of the metal in the blood, and the two are expelled from the body in the urine.
"Arsenic warfare" never materialized, but chelation therapy has been FDA-approved to treat lead poisoning and other heavy-metal toxicities. According to the NIH, more than 800,000 patient visits were made for chelation therapy in the United States in 1997. Cost ranges for the course of therapy run between $2,000 and $4,000.
While chelation therapy was being used for metal toxicities, a number of clinicians noticed some patients with heart disease and angina seemed to be improving as well. Word spread, and chelation therapy became a common, off-label procedure for people with angina, atherosclerosis and other conditions in the 1960s and 1970s.
Then, various small studies appeared to discredit the technique, and mainstream cardiology moved away from the treatment.
Alternative medicine practitioners, however, stuck with it.
"Chelation, or EDTA, became almost an underground movement in medicine and cardiology," says Dr. Gervasio A. Lamas, director of cardiovascular research and academic affairs at Mount Sinai Medical Center and Miami Heart Institute. Lamas heads up the current NIH study.
Scientists now feel the earlier studies were not conclusive. Meanwhile, a spate of more recent studies has renewed interest in chelation therapy, though these are also largely inconclusive.
There are still, however, thousands of case reports testifying to chelation therapy's success with cardiovascular disease.
The NIH study intends to settle the matter once and for all.
Study leaders have lined up a list of heavy-hitting medical institutions such as Brigham and Women's Hospital in Boston and Duke Clinical Research Institute to participate.
"For me to be able to gather the team we have on this, I think that's really a sea change," Lamas says. "People are really interested in settling this question."
"I was very pleased to see that the NIH is going to support a very large-scale study to answer the question once and for all. I think it's very important to do this work," says Dr. Woodson Merrell, executive director of the Continuum Center for Health and Healing at Beth Israel Medical Center in New York City.
"If it shows that chelation does work, then that would certainly add something to our armamentarium. If it shows it doesn't work, then people spending a lot of money could better spend it elsewhere," Merrell adds.
The trial, scheduled to last five years and to be carried out at 100 sites, will involve 2,372 patients, all 50 years or older, who have had a heart attack. People will be randomly assigned to receive either a standardized chelation solution or a placebo. Each group will also be randomly assigned to receive high-dose or low-dose vitamin/mineral supplements.
The chelation therapy will be administered by IV over about three hours, first once a week and then afterwards every other month for a total of about 40 infusions; rare side effects, if it's given too fast, can include cramping in the arms or jaw or some tingling.
The researchers will be looking to see if the patients suffer additional heart attacks, stroke, hospitalization for angina, coronary revascularization or death.
The study is not specifically intended to ferret out why chelation therapy works -- only if it works.
Nevertheless, Lamas and other scientists have some theories. One hypothesis holds that EDTA may reduce oxidized LDL, or "bad," cholesterol in the blood. Oxidized LDL is extremely toxic.
Another explanation is that EDTA may bind with calcium from the fatty plaques that block arteries and lead to coronary artery disease.
"I honestly don't know what mechanism it is. And from my past experiences of looking at the mechanisms of cardiovascular therapies, it's often what you expect least," Lamas says. "We're embarking on a large trial without knowing which one it is and, at end of it all, we may have a therapy that works and we will then have to retrace our steps and figure out why."
At the very least, clinicians should have an answer.
"We just don't have a comfort level now whether it works or doesn't work," Merrell says. "It'll be really good to know."
What To Do
Patient enrollment for the NIH trial does not start until March 2003, but interested individuals should call 305-674-2162.
For more information on the upcoming trial, visit the National Center for Complementary and Alternative Medicine. For more details about chelation therapy, visit the American Heart Association, which does not approve of the process for heart ailments.