Heart-attack survivors were less likely to have future cardiac complications after getting the cocktail of chemicals and vitamins known as chelation therapy, according to a U.S. government-funded study that immediately drew skepticism from top doctors in the field.
The treatment, in use for 50 years, is designed to extract metals such as iron from the blood. It combines 10 components, including the synthetic amino acid EDTA, vitamins B and C, electrolytes, a local anesthetic and the anti-clotting drug heparin. Despite a lack of scientific evidence proving its effectiveness, 111,000 Americans had the therapy in 2007, the latest year for which the U.S. has data.
The study, presented yesterday at the American Heart Association meeting in Los Angeles, found the therapy cut by 18 percent the risk of death, heart attack, stroke, repeat artery-clearing procedures and hospitalization. It was an “unexpected” result that will require more study, Gervasio Lamas, the report’s chief lead author, said in an interview.
“The most exciting part of this study is there is a potential signal of benefit,” said Lamas, chief of Columbia University’s division of cardiology at Mount Sinai Medical Center in Miami Beach, Florida. “Everyone will need some time to understand and digest this study.”
Patients in the trial were given 40 infusions of chelation therapy. The first 30 doses were given once a week and took at least three hours to administer, a slow infusion designed to reduce the risk of side effects.
Thirty percent of patients enrolled in the study were diabetic and they derived the most benefit, with a 39 percent reduction in heart risk. There was no evidence that chelation reduced death rates. There were two unexpected severe side effects, including one death, in each of the treatment arms.
Mariell Jessup, medical director of the Penn Medicine Heart and Vascular Center, said it would take numerous studies with similar results to get cardiologists to embrace the approach.
Most of the benefit stemmed from a reduction in repeat procedures to restore blood flow to the heart, Jessup said in an interview. “This isn’t ready for prime time. It wasn’t convincing from a clinical standpoint.”
Instead of having the infusions, which cost about $5,000 for a course of therapy, people should go to the gym or have a dietician bring heart healthy meals to their house instead, Jessup said. “Why would they spend that money?”
The therapy is already widely used by alternative medicine providers, who first became aware of its potential because of a report that it reduced chest pain in 1956. A different type of chelation therapy is approved to remove metals like lead and iron from the bloodstream. The treatment used in the study isn’t formally approved in the U.S.
Two federal agencies shared the cost of the $31.6 million study: The National Heart, Lung and Blood Institute and the National Center for Complementary and Alternative Medicine, both based in Bethesda, Maryland. The trial, which involved 1,708 heart attack patients, helped clarify the risks and benefits of the three-hour infusions, said Gary Gibbons, head of the heart institute in an interview.
“The study shows chelation can be administered in a way that is safe and where there is a clear but marginal benefit,” Gibbons said. “It’s an important first step, but it’s just a first step. More research needs to be done before it can join the mainstream of cardiovascular care.”
The study was originally designed to have 2,300 patients, with a three year enrollment. Instead, it took seven years, including a halt in September of 2008 while the forms used to disclose the potential risks to patients were reviewed and updated to include the possibility of death.
‘Steeped in Controversy’
“To suggest that this study is steeped in history and controversy would be an understatement,” said Paul Armstrong, a cardiologist at the University of Alberta and director of the Canadian coordinating center for global cardiovascular research. “These results are hypothesis generating, not practice changing,” Armstrong said at a press conference.
The study was a good use of the public’s money, Gibbons said. A lot of Americans are undergoing the treatment without any guidance or information about its risks, creating a lot of confusion and controversy, he said.
“We stand behind how it was executed and the data speaks for itself,” Gibbons said.