Prognostic Impact of Subsequent Acute Coronary Syndrome and Unplanned Revascularization on Long‐Term Mortality After an Index Percutaneous Coronary Intervention: A Report From a Japanese Multicenter Registry

BACKGROUND Whereas composite end points are often used in clinical trials of percutaneous coronary interventions (PCI), the impact of individual components on subsequent survival is incompletely defined. We evaluated the association of subsequent acute coronary syndromes (ACS) and unplanned coronary revascularization post-PCI with long-term survival. METHODS AND RESULTS From 2009 to 2011, the KiCS-PCI (Keio interhospital Cardiovascular Studies) consecutively enrolled patients undergoing PCI in 14 Japanese teaching hospitals. We identified patients who experienced ACS or unplanned coronary revascularization following their index PCI and compared subsequent survival during the 2-year follow-up period using propensity-matched cohorts of patients who did and did not experience these events. Cox proportional hazard models were used to assess 2-year all-cause mortality. Because unstable angina is less severe than acute myocardial infarction, we also generated a separate propensity-matched cohort for UA post-PCI. Among 3348 PCI patients (mean age, 67.5±10.7 years; 79.7% male), 214 (6.4%) experienced a subsequent ACS (168 events [78.5%] were unstable angina), and 198 (5.9%) underwent unplanned revascularization. In the propensity-matched cohorts, patients with a subsequent ACS admission had an increased risk of mortality as compared with those without (hazard ratio, 4.73; 95% confidence interval=1.35-16.6; P=0.015), whereas those with an unplanned revascularization did not have significantly higher risk (hazard ratio, 2.97; 95% confidence interval=0.57-14.3; P=0.19). Among unstable angina events, no association with mortality was observed (hazard ratio, 1.39; 95% confidence interval=0.48-4.00; P=0.54). CONCLUSIONS In the KiCS-PCI registry, the incidence of a subsequent ACS was associated with higher mortality, but this association was less apparent after unplanned coronary revascularization or unstable angina. The prognostic implications of different outcomes in a composite end point should be considered when interpreting the results of clinical trials in PCI.