Effect of plasma homocysteine concentration on early and late events in patients with acute coronary syndromes

Background-Although a raised plasma homocysteine is a risk factor for vascu lar disease, it is not known whether it is associated with an adverse cardi ac outcome in patients admitted with acute coronary syndromes. We evaluated the relationship between plasma homocysteine and short-term (28 days) and Ion coronary syndromes. g-term (median 2.5 years) prognosis in acute. Methods and Results-We evaluated the relationship of quintiles of homocyste ine to fatal and nonfatal coronary disease early (28 days) and late (29 day s to a median of 2.5 years) after admission to a single unit of patients wi th unstable angina (n=204) and myocardial infarction (n=236), The end point s studied were cardiac death (n=67) and/or myocardial (re)infarction (n=30) , Cox regression and logistic regression were used to estimate the relation ship of homocysteine to coronary events. The event rate within the first 28 days (22 cardiac deaths and 5 nonfatal infarctions) was not related to the admission homocysteine level. In the 203 unstable angina and 214 myocardia l infarction survivors, an apparent threshold effect was seen on long-term follow-up, with a significant step-up in the frequency of events between th e lowest 3 quintiles (14 cardiac deaths and II nonfatal infarctions) and th e upper 2 quintiles (31 fatal and 12 nonfatal events). Patients in the uppe r 2 quintiles (>12.2 mu mol/L) had a 2.6-fold increase in the risk of a car diac event (95% Cl, 1.5 to 4.3, P<0.001). Conclusions-Elevated total homocysteine levels on admission strongly predic t late cardiac events in acute coronary syndromes.