Background: The time course of events after acute coronary syndromes might influence the timing and duration of therapeutic interventions. We investigated the impact of risk status and ST-segment category at presentation.
Methods: The timing of death, reinfarction, stroke and major bleeding within 6 months of acute coronary syndromes was determined in 46,829 patients enrolled in the Global Registry of Acute Coronary Events (GRACE). Acute coronary syndromes were classified by elevation (n = 17,668), depression (n = 8,542), or neither (n = 20,619) in the ST segment. GRACE risk scores and hazard ratios (HR) were determined for three time periods: 0-4, 5-15 and 16-180 days.
Results: ST-segment elevation was associated with a higher early risk of death than was ST-segment depression (0-4 days, HR 1.89, 95% CI 1.60-2.24 versus 5-15 days, HR 1.26, 95% CI 1.05-1.50), but after 15 days the risk was reversed (16-180 days, HR 0.85, 95% CI 0.75-0.97). Throughout the study, patients with ST-segment deviation had a higher mortality risk than those without. Within each ST category, the highest GRACE risk scores were associated with a 10-40-fold greater risk of death than the lowest scores (all categories P <0.0001). Most deaths occurred after day 4 (57%, 74%, and 78% for ST-segment elevation, depression and neither, respectively).
Conclusion: The timing of events after acute coronary syndromes was affected by ST category and influenced by GRACE risk score within each electrocardiographic category of acute coronary syndromes. Risk stratification should, therefore, include multiple risk factors rather than ST shift alone.