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Folate May Be Risky After Heart Bypass

May Want to Hold Off On Starting Some Vitamin Supplements After Angioplasty

From the WebMD Archives


April 3, 2003 (Chicago) -- After undergoing procedures to open blocked arteries many people commit to healthy lifestyles: exercise, a balanced diet and -- many times - vitamin supplements. But not all vitamins are heart healthy and results of a new study suggest that one combination -- folate plus vitamins B6 and B1 -- might do more harm than good.

This new study actually flies in the face of previous research which suggested that folate supplements might actually benefit some heart patients after surgery.

This study of over 600 patients who had blocked arteries propped open with tiny, flexible mesh tubes, a procedure called stenting, found that those who took a high dose folate supplements for six months after the procedure were more likely to have stent failure than those who took a placebo. Making the matter worse, the patients that took the vitamin supplements actually had an increase in complications.

Helmut Lange, MD, of Kardiologische Praxis, in Bremen, Germany said that patients who took the vitamin supplement mix had clear evidence of new narrowing in the stented arteries: the arterial opening had shrunk compared to stented patients who didn't take the folate. Outright stent failure, which is called restenosis, occurred in 35% of the patients put on the vitamin supplements, while the stent failure rate in patients who didn't take the supplements was 27%.

Moreover, 16% of folate-treated patients needed subsequent procedures to re-open the artery compared to 11% of the patients in the group that didn't take the folate supplements.

The research was reported at the American College of Cardiology 52nd Annual Scientific Session held here this past week.

Lange tells WebMD he was actually surprised by the study results since an earlier study suggested that taking vitamin supplements could "reduce the rate of restenosis by half."

After those earlier results were reported some cardiologists began recommending folate supplementation for stent patients. But Lange says results of this new study suggest that patients should be advised against starting folate supplementation after undergoing stenting.

Folate supplements decrease blood levels of homocysteine, which is considered a risk factor for cardiovascular disease. "So the hypothesis was that administration of a homocysteine-lowering vitamin combination would be protective," says Lange.

Lange says the supplement levels were high -- folate 1.2mg, B6 48 mg, and B12, 0.06mg -- which might influence the results. "The amount of folate in a multi-vitamin is .4mg, so we were three times that dose," he says.

This super dosing may provide a clue to explain the unexpected results. Folate, says Lange, promotes cell growth so high doses might trigger an overgrowth of cells that line arteries. As the cells grew and formed new tissue the newly thickened arterial lining could then press against the stent causing it to narrow.

David O. Williams, MD, director of the Cardiac Catheterization Laboratories and Interventional Cardiology at Rhode Island Hospital in Providence, R.I., says that Lange's study is interesting, but he doesn't think it provides proof for a link between folate supplements and stent failure. "I wouldn't tell a patient to stop taking folate acid. What this is telling us is that the benefit reported in the earlier study is probably not 'real' but that doesn't mean this is a real risk. If they did another study, I doubt they would replicate these results."

Show Sources

Sources: American College of Cardiology 52nd Annual Scientific Session, Session 31 Late Breaking Clinical Trials in Interventional Cardiology II, presented March 30, 2003. Helmut Lange, MD, of Kardiologische Praxis, in Bremen, Germany. David O. Williams, MD, director of the Cardiac Catheterization Laboratories and Interventional Cardiology at Rhode Island Hospital in Providence, R.I.
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