Results from a major trial on controversial chelation therapy for patients
with a history of heart attack find a modest benefit from the expensive
treatment, but experts conclude there's no clear evidence supporting its
Still, "groups that advocate for chelation and groups that oppose chelation
will both find comfort in the results," said one expert not connected to the
study, Dr Stephen Green, associate chairman in the department of cardiology at
North Shore University Hospital in Manhasset, NY.
What is chelation therapy?
Chelation therapy involves dozens of arduous infusions conducted over a
period of years, aimed at leaching excess metals from the body. Patients
typically also receive high doses of vitamins and minerals.
The therapy has been offered to heart patients by some clinics across the
United States for decades, although its use for this purpose has been considered
controversial and it has never received approval as a heart disease treatment
from the US Food and Drug Administration.
Findings from the same study were also presented earlier this month at the
annual meeting of the American College of Cardiology (ACC) in San Francisco, and
at last fall's annual meeting of the American Heart Association.
Speaking at the ACC meeting, the study's lead researcher said that the modest
benefit noted in the study had not made him any more ready to recommend
"These findings should stimulate further research, but are not by themselves
sufficient to recommend the routine use of chelation therapy and high-dose
vitamins in most patients," said Dr Gervasio Lamas, chief of the Columbia
University division of cardiology at Mount Sinai Medical Center, in Miami Beach,
How the study was done
The trial, which was funded by the US National Institutes of Health, involved
more than 1 700 patients from the United States and Canada who had suffered a
previous heart attack. Most were already taking standard therapies such as daily
aspirin, cholesterol-lowering statins or blood pressure medications.
In the new analysis of the data, the patients were divided into two groups:
high-dose vitamin/mineral supplements plus chelation or "dummy" placebo
Chelation therapy consisted of 40 three-hour sessions with the IV infusions
spread over anywhere between 50 and 110 weeks. Doses of vitamins and minerals
given were much higher than recommended daily intakes.
After an average follow-up of more than four and a half years, the team did
see a slight benefit among the group who took the vitamins/minerals in
combination with chelation therapy. 26% of people in this group experienced some
kind of cardiovascular event such as heart attack, stroke or hospitalisation for
angina (chest pain) - less than the 30% seen among those who got placebo/placebo
Still, the gap was not huge and Lamas, who does not use chelation therapy in
his own practice, said he cannot recommend it at this time.
The researchers also noted that the drop-out rate among participants was
relatively high: 281 people in the placebo arm stopped treatment before the
study's end, as did 233 of those taking chelation.
"The message really is a cautious message," Lamas said. "We brought something
that has been an alternative medicine treatment into the realm of scientific
inquiry and found unexpected results that may merit future research. However, we
don't think that the results of any single trial are enough to carry this novel
hypothesis into daily use for patients."
Helpful but expensive and side effects
In an editorial published in JAMA, the journal's editor-in-chief, Dr
Howard Bauchner said that "based on full consideration of the strengths and
limitations of [this study], the conclusion is clear and should influence
practice - these findings do not support the routine use of chelation therapy as
secondary prevention for patients with previous [heart attack] and established
But Green said the debate over chelation's effectiveness may continue.
"The use of chelation therapy for coronary artery disease has had its
advocates for decades, but predominantly outside of regular medical circles,"
Green noted. "This is because there has not been what was considered a good
hypothesis to explain why it should work for coronary arteriosclerosis
[hardening of the arteries]."
Beyond that are safety concerns linked to the therapy's removal of calcium
from the bloodstream. In the study, the researchers noted that the treatment
"may cause hypocalcemia [abnormally low calcium in the blood] and death."
Speaking at the time of the ACC meeting presentation in San Francisco,
cardiologist Dr Tara Narula, associate director of the cardiac care unit at
Lenox Hill Hospital in New York City, was similarly dubious of chelation's
"Although it is noteworthy that chelation may be helpful, it is an expensive
treatment and does carry significant side effects," she said.
There's more on the care of heart attack patients at the US
National Heart, Lung, and Blood Institute.