Baseline glutathione peroxidase activity affects prognosis after acute coronary syndromes

Oxidative stress is associated with atherosclerosis and plaque lesions in experimental in vitro models. Few in vivo studies have examined the association between redox status and the prognosis of acute coronary syndromes.We undertook a prospective, observational study of 137 patients who had been admitted because of an acute coronary syndrome. We determined glutathione peroxidase activity (a marker of systemic antioxidant status) and recorded clinical and angiographic features and cardiovascular events (cardiovascular death, reinfarction, readmission with a new ischemic event, or need for coronary revascularization).The mean age of the patients (78% of whom were men) was 61.7 +/- 10.9 years; 76% were admitted with non-ST-segment-elevation acute coronary syndrome. Left ventricular ejection fraction was normal in 61%. In the 23.4% who experienced cardiovascular events, glutathione peroxidase activity was higher (mean, 2.38 vs 1.76 mU/mg of protein; P < 0.01). Two-year event-free survival was lower in patients whose glutathione peroxidase activity was higher than the 50th percentile (63% vs 82%; P = 0.01). Multivariate analysis showed a direct independent relationship between glutathione peroxidase activity and cardiovascular events (hazard ratio, 3.72; 95% confidence interval, 1.53-9.02; P < 0.01).We conclude that patients who experienced acute coronary syndromes and events during follow-up had higher plasma glutathione peroxidase activity, and that glutathione peroxidase activity was an independent predictor of events during follow-up.