B Vitamins May Be Risky After Heart Surgery
Folate Combination Linked to Artery Narrowing Following Angioplasty
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
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
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.
"While the overall results of this study show a negative
effect from these vitamins, that detrimental effect was not present in patients
who had high homocysteine levels."
Another possible explanation for the study findings: At the
start of Lange's study, the use of cholesterol-lowering statin drugs such as
Lipitor and Zocor were used by a surprisingly low number of patients -- only
38% of those getting the vitamins and 42% of those on placebo drugs.
"And that may have been enough to shade the results,"
Siegel tells WebMD. These drugs are routinely prescribed to heart patients, and
especially candidates for angioplasty.