B Vitamins May Be Risky After Heart Surgery
Folate Combination Linked to Artery Narrowing Following Angioplasty
WebMD News Archive
June 23, 2004 -- A folate and vitamin B-based therapy that lowers homocysteine levels may actually cause more harm than good. Contradicting previous findings and popular opinion, a new study indicates that folate and other B vitamins may actually increase the risk of artery narrowing following angioplasty.
In angioplasty, surgeons use tiny balloons to open narrowed heart arteries. A flexible mesh tube called a stent is usually placed in the artery to prop it open and prevent renarrowing.
Three B vitamins -- including folate -- have been considered an insurance policy to prevent renarrowing after surgery. That's because the nutrients work together to help lower levels of homocysteine, which has been linked to a higher risk of heart disease, such as the buildup of plaque in arteries of the heart.
The American Heart Association has not stated that high homocysteine level is a major risk factor for heart disease, unlike major risks such as high cholesterol or diabetes.
In a well-publicized study the three-vitamin regimen lowered the risk of renarrowing after angioplasty by almost 40%.
New Study, Opposite Results
But now, European researchers find an opposite effect and report that patients who took folate, B-6, and B-12 following stented angioplasty actually had a higher risk of renarrowing than those getting placebo drugs. After studying 636 patients, they report in this week's New England Journal of Medicine that:
- 35% of those put on vitamin supplements for 6 months experienced outright stent failure, compared with only 27% who took placebo pills.
- 16% of vitamin-treated patients needed subsequent procedures to reopen arteries, compared with 11% of those getting the phony drugs.
- The arterial openings in vitamin-taking patients shrunk more, to an average of 1.59 millimeters compared with 1.74 millimeters in the placebo group.
While the differences were slight, does this mean that B vitamin therapy shouldn't be recommended following angioplasty, as suggested by study researcher Helmut Lange, MD, and his colleagues?
Not necessarily, say two experts contacted by WebMD.
Reading Between the Results
"I have been using folate therapy for many years, and will continue to do so -- for patients who have high homocysteine levels," says cardiologist Stephen Siegel, MD, of New York University Medical Center.