RESUMEN
AIMS: L-arginine is a substrate for nitric oxide (NO) synthesis in vascular endothelial cells. NO bioavailability is decreased during myocardial infarction (MI). It might be expected that administration of L-arginine may maintain NO production and alleviate the course of MI. The aim of the study was to assess safety and effects of treatment with L-arginine on the clinical course of MI. METHODS AND RESULTS: 792 patients (mean age 64 years, 551 men) with ST segment elevation MI admitted within 24h after the onset of symptoms were randomized to oral L-arginine (3.0 t.i.d p.o. for 30 days) or placebo on top of routine therapy. The end point which was the composite of 30 day cardiovascular death, reinfarction, successful resuscitation, shock/pulmonary edema or recurrent myocardial ischemia occurred in 24% patients treated with L-arginine and 27% with placebo (OR 0.63, 95% CI 0.39-1.02, p=0.06). The end point was observed less frequently in 226 patients with hyperlipidemia (19 vs 31, p<0.05). No serious adverse effects were observed during L-arginine supplementation. CONCLUSIONS: This study, which is the first attempt to use L-arginine in MI, showed that oral L-arginine supplementation was well tolerated. Beneficial nonsignificant trend was observed towards reduction of major clinical events.