Background: To evaluate the possible independent impact of circulating total homocysteine (tHcy) levels on long-term cardiovascular mortality, in patients with either ST-segment elevation myocardial infarction (STEMI), or non-ST-segment elevation acute coronary syndromes (NSTE-ACS).
Methods: A total of 458 STEMI and 476 NSTE-ACS patients who presented consecutively, within the first 12 and 24 h of index pain respectively were studied. Each cohort was divided according to tertiles of circulating tHcy levels upon presentation. Early (30 days) and late (31 days through 5 years) cardiovascular mortality was the predefined study endpoint.
Results: There was no difference in the risk of 30-day cardiovascular death among the tertiles of tHcy in patients with STEMI (7.2%, 8.5% and 12.4% for the first, second and third tertiles respectively; p(trend)=0.3) or NSTE-ACS (3.1%, 3.8% and 5.7% for the first, second and third tertiles respectively; p(trend)=0.5). Patients in the upper tHcy tertile were at significantly higher unadjusted risk of late (from 31 days trough 5 years) cardiovascular death than those in the other two tertiles in STEMI (23.4%, 27.9% and 41.8% for the first, second and third tertiles respectively; p(trend) <0.001), and NSTE-ACS (24.7%, 28.1% and 45.6% for the first, second and third tertiles respectively; p(trend) <0.001) cohorts. However, after adjustment for baseline differences, there was no significant difference in the risk of late cardiovascular death among tHcy tertiles in either cohort. When circulating tHcy levels were treated as a continuous variable, they were significantly associated with late cardiovascular death (p<0.001 for both cohorts) by univariate Cox regression analysis, but not by multivariate Cox regression analysis (p=0.8, and p=1 for STEMI and NSTE-ACS cohorts, respectively).
Conclusions: Based on the present data circulating tHcy levels determined upon admission do not serve as an independent predictor of long-term cardiovascular mortality in patients with either STEMI or NSTE-ACS.