III. CLINICAL STUDIES
A. Willems et al.
Study question: The mechanism responsible for an increased risk for coronary artery disease is unclear; it is generally assumed that hyperhomocystinemia causes endothelial dysfunction. It is unknown whether plasma homocysteine levels improve coronary endothelial function in patients with hyperhomocystinemia and symptomatic coronary heart disease. This study evaluated the effect of the administration of folic acid and vitamin B12 on coronary endothelial function.
Methods: There were 15 patients scheduled for balloon coronary angioplasty with plasma homocysteine levels greater than 16 (j,mol/L who were randomized for six months of treatment with folic acid 5 mg, cobalamin 400 (J.g daily, or placebo. Coronary endothelial function was evaluated in a noncoronary vessel using acetylcholine infusion.
Results: In the folic-acid-treated group coronary blood flow increased 96% after acetylcholine infusion when compared with a decrease of 16% of the coronary blood flow in the placebo-treated group(p = 0.005).
Conclusions: This study suggests that coronary endo¬thelial function improves after treatment with folic acid and cobalamin. It is unclear, however if the salutary effect observed bears any relation to atheroma formation and its progression to thrombotic events.