Researchers Find Vitamins Can Create Sustained Protection
Against Repeat Blockage Of Coronary Arteries
A team of researchers led by UCSD cardiologist Guido Schnyder, M.D. found that a six-month regimen of folic acid, vitamin B-12, and vitamin B-6 had lasting benefits -- preventing patients who had undergone coronary angioplasty procedures from redeveloping blocked arteries for a full year, including the six-month period after the patients stopped taking the vitamins.
The findings, reported in the August 28 issue of the Journal of the American Medical Association, are an extension of the first ever clinical trial to examine the effects of this vitamin combination on treating heart disease. That study was also led by Schnyder, a visiting scholar from Switzerland currently working in the UCSD School of Medicine Division of Cardiology.
Coronary angioplasty is a procedure in which atherosclerotic plaques, which build up and clog the coronary arteries, are compressed against the vessel wall by expanding a balloon-like device inserted through a catheter that has been threaded through the artery. Hundreds of thousands of these procedures are performed in the U.S. each year. Up to 40 percent of patients who undergo this procedure develop restenosis, or re-narrowing of the vessel, erasing the initial benefit and warranting repeat angioplasty or bypass operation.
In Schnyder's earlier study of 205 patients (New England Journal of Medicine, 2001; 345:1593-1600) all from the Swiss Cardiovascular Center 105 were given the vitamin combination and 100 were given placebo for six months. During that period, the patients who took the vitamin combination showed a 48 percent reduction in the development of restenosis compared to patients receiving placebo. In this latest research, Schnyder extended the follow-up observation period from six months to one year and added 348 more patients to the study.
â€œBased on our earlier findings, we wanted to see whether the benefits of the vitamin therapy would continue after the patients stopped taking the vitamins,â€? Schnyder said. â€œIt was important to follow these patients for another six months, because that's the time frame in which restenosis typically occurs. We've now shown that the vitamin combination didn't just delay the development of restenosis, it prevented it.â€?
In expanding the study to more than 500 test subjects, Schnyder said he also expanded its clinical focus -- to look not only at the development of restenosis, but also to assess the patients' need for further vascular intervention one year after their initial angioplasties. He says the vitamin regimen, which lowers homocysteine levels, decreased by 38 percent the need for renewed interventional revascularization, i.e., repeat angioplasties or heart bypass operations.
â€œThe vitamin treatment we've applied lowers homocysteine levels, which appears to prevent the formation of an excessive amount of scar material which often builds up inside an artery following angioplasty,â€? Schnyder said. â€œThis study makes it clear that homocysteine-lowering therapy with folic acid, vitamin B-12 and vitamin B-6 significantly lowers the incidence of major adverse events after angioplasty.â€?
The study was funded by the Swiss National Science Foundation and Swiss Cardiovascular Center at the University Hospital in Bern, Switzerland. Also involved in the study were Marco Roffi, M.D. (The Cleveland Clinic Foundation, Cleveland, OH), and Yvonne Flammer M.D., Riccardo Pin, M.D., and Otto M. Hess, M.D. (Swiss Cardiovascular Center, University Hospital, Bern, Switzerland).
PLEASE NOTE: Dr. Schnyder's full name is correctly pronounced GEE-doh (hard 'g') SHNEE-der.