Long-Term Cardiovascular Mortality After Procedure-Related or Spontaneous Myocardial Infarction in Patients With Non–ST-Segment Elevation Acute Coronary Syndrome

Abstract

Background— The present study was designed to investigate the long-term prognostic impact of procedure-related and spontaneous myocardial infarction (MI) on cardiovascular mortality in patients with non–ST-elevation acute coronary syndrome. Methods and Results— Five-year follow-up after procedure-related or spontaneous MI was investigated in the individual patient pooled data set of the FRISC-II (Fast Revascularization During Instability in Coronary Artery Disease), ICTUS (Invasive Versus Conservative Treatment in Unstable Coronary Syndromes), and RITA-3 (Randomized Intervention Trial of Unstable Angina 3) non–ST-elevation acute coronary syndrome trials. The principal outcome was cardiovascular death up to 5 years of follow-up. Cumulative event rates were estimated by the Kaplan-Meier method; hazard ratios were calculated with time-dependent Cox proportional hazards models. Adjustments were made for the variables associated with long-term outcomes. Among the 5467 patients, 212 experienced a procedure-related MI within 6 months after enrollment. A spontaneous MI occurred in 236 patients within 6 months. The cumulative cardiovascular death rate was 5.2% in patients who had a procedure-related MI, comparable to that for patients without a procedure-related MI (hazard ratio 0.66; 95% confidence interval, 0.36–1.20, P =0.17). In patients who had a spontaneous MI within 6 months, the cumulative cardiovascular death rate was 22.2%, higher than for patients without a spontaneous MI (hazard ratio 4.52; 95% confidence interval, 3.37–6.06, P <0.001). These hazard ratios did not change materially after risk adjustments. Conclusions— Five-year follow-up of patients with non–ST-elevation acute coronary syndrome from the 3 trials showed no association between a procedure-related MI and long-term cardiovascular mortality. In contrast, there was a substantial increase in long-term mortality after a spontaneous MI. Clinical Trial Registration— URL: http://www.controlled-trials.com/ISRCTN82153174 (ICTUS); http://www.controlled-trials.com/ISRCTN07752711 (RITA-3).