B Vitamins May Be Risky After Heart Surgery
Folate Combination Linked to Artery Narrowing Following Angioplasty
WebMD News Archive
Reading Between the Results continued...
"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.
Howard C. Herrmann, MD, director of interventional cardiology
and cardiac catheterization laboratories at the University of Pennsylvania
Medical Center, wrote an accompanying editorial to Lange's study and notes
several differences between this study and the study that showed a benefit from
For one thing, higher doses of vitamin supplements were used in
Lange's research, especially B-6, says Herrmann. "We don't really know the
role of B-6 and B-12, other than they work together with folate to reduce
homocysteine," he tells WebMD.
The people studied in the two trials were also different. The
study that showed a benefit from vitamin supplement had more smokers and people
with diabetes -- factors that can boost homocysteine levels. The study also
showed the biggest benefit from vitamin therapy occurred in patients treated
with angioplasty alone, rather than those getting angioplasty with stents. In
Lange's study, all patients got stents.
Lessons to Learn
What does this all mean?
"Folate supplementation has been considered safe and
completely benign," Herrmann tells WebMD. "And even if its effect on
[renarrowing] wasn't as great as what was previously shown, you could still
say, 'why not give it to people?' But now, there's a study that suggests it
could be harmful, so we may need to rethink that."
Something else to reconsider: Priorities in treating
angioplasty patients, he says. Since the 1990s, more patients have been treated
with newer, second-generation stents that are coated with medication that helps
prevent renarrowing, which has reduces the risk from about 20%-30% to single
"[Renarrowing] is not as big an issue these days, with the
advent of drug-eluting stents, so our focus should be more on preventing new
cardiovascular disease," he says.