A 2002 study reported, funded by the Swiss National Science Foundation reported that a six-month regiment of taking folic acid, vitamin b12, and vitamin b6 can be instrumental in the prevention of recurring blocked arteries in coronary angioplasty patients.

The findings, which were published in the Journal of the American Medical Association are an extension of a clinical trial that examined the effects of combining vitamins on the treatment of heart disease. The treatment apparently works by reducing levels of homocysteine, and amino acid which has long been associated with heart attacks.

The original study involved 205 patients who were given either a vitamin combination of vitamin b6, vitamin b12, and folic acid or a placebo for six months. Over that time period, the patients who took the combination of vitamins showed a 48% reduction in the development of restenosis, or re-narrowing of the vessel, compared with patients who received the placebo.

The new study added 348 new patients, and extended the follow-up observation period from six months to one year. The head researcher, Dr. Guido Schnyder, says that this time extension is important, since six months to one year is the time frame in which restenosis typically recurs. Out of all the patients monitored, the need for additional bypass operations was reduced by 38% over the entire year. This shows that the vitamin actually prevents the development of restenosis, rather than just preventing it.

Dr. Robert Bonow, the chief of cardiology at Chicago's Northwestern Memorial Hospital, and president of the American Heart Association said that the results of the study are very encouraging, offering more evidence that B vitamins are very important in maintaining healthy blood vessels.