| Peabody 2006-01-05, 12:55 am |
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L-arginine may increase mortality risk after myocardial
infarction
NEW YORK (Reuters Health) - The amino acid L-arginine
provides no benefit to patients who have experienced an
ST-segment elevation myocardial infarction, and may even
increase mortality in patients over the age of 60,
Baltimore-based researchers report.
Based on the hypothesis that L-arginine can reduce vascular
stiffness, Dr. Steven P. Schulman, from Johns Hopkins
Hospital, and his associates initiated the prospective
Vascular Interaction with Age in Myocardial Infarction
(VINTAGE MI) clinical trial, in which 153 patients were
randomly assigned to L-arginine (up to 3 grams three times
daily) or placebo for 6 months after experiencing a first
MI.
According to their report in the January 4th issue of the
Journal of the American Medical Association, 6-month
follow-up data were obtained for 55 subjects in the
L-arginine group and 59 in the placebo group.
There were no significant changes in either group in
measures of ejection fraction, arterial elastance, arterial
compliance, pulse pressure, or pulse wave velocity.
However, six deaths occurred in the L-arginine group,
including five among patients age 60 years or older, and
none in the control group (p = 0.01), which led to early
termination of the study.
Dr. Schulman's team proposes several possible mechanisms by
which L-arginine could cause post-MI damage, including
increased generation of reactive oxygen species,
homocysteine production, and increased activity of the
inducible isoform of nitric oxide synthase.
"L-arginine therapy should not be given to patients
following a myocardial infarction," they advise.
Furthermore, they add, "L-arginine therapy in older
patients with diffuse atherosclerosis may worsen clinical
outcomes.
JAMA 2006;295:58-64.
The Wall Street Journal 1/4/06 article on this also says:
"L-arginine also is sometimes touted as a treatment for
hypertension, angina, heart failure and sexual dysfunction."
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