L-Arginine Use Opposed In Heart Attack Patients

BALTIMORE--Supplementation with arginine following heart attack may not improve ejection fraction or vascular stiffness and may even promote mortality, according to the Vascular Interaction With Age in Myocardial Infarction (VINTAGE MI) trial, published in the Journal of the American Medical Association (JAMA) (295, 1:58-64, 2006). Arginine has been linked to heart health for its ability to boost levels of nitric oxide, which relaxes blood vessels.

Researchers from Johns Hopkins Medical Institutions and Maryland Medical Research Institute conducted a single-center, randomized, double blind, placebo-controlled trial on 153 patients who had experienced their first ST-segment elevation myocardial infarction. The mean age of enrollees was 60 years (n=77) and 68 percent (n=104) were men. The test subjects were randomized to receive supplemental arginine at a goal dose of 3 g three times per day or matching placebo for six months. All patients were monitored for changes in ejection fraction and noninvasive measures of vascular stiffness, and clinical events. A subgroup of test subjects aged 60 years or older was assessed for changes in gated blood pool-derived ejection fraction over the same test period.

At baseline, vascular stiffness measurements and left ventricular function were similar between the placebo and L-arginine groups, and there were no significant changes in these end points in either group during the test period, including patients 60 years or older. However, during the six-month test period, six participants (8.6 percent) in the L-arginine group died, whereas there were no deaths in the placebo group. In light of these fatalities, the study's data and safety monitoring committee closed enrollment.

The researchers concluded supplemental arginine, when added to standard post-infarction therapies, does not improve vascular stiffness measurements or ejection fraction, may be associated with higher post-infarction mortality, and should not be recommended following acute myocardial infarction.