Background: Optimal intensity is unclear for P2Y12receptor blocker therapy after percutaneous coronary intervention (PCI) in real-world clinical practice.Methods and Results: From the CREDO-Kyoto Registry, the current study population consisted of 25,419 patients (Cohort-2: n=12,161 and Cohort-3: n=13,258) who underwent their first PCI. P2Y12receptor blocker therapies were reduced dose of ticlopidine (200 mg/day), and global dose of clopidogrel (75 mg/day) in 87.7% and 94.8% of patients in Cohort-2 and Cohort-3, respectively. Cumulative 3-year incidence of GUSTO moderate/severe bleeding was significantly higher in Cohort-3 than in Cohort-2 (12.1% and 9.0%, P<0.0001). After adjusting 17 demographic factors and 9 management factors potentially related to the bleeding events other than the type of P2Y12receptor blocker, the higher bleeding risk in Cohort-3 relative to Cohort-2 remained significant (hazard ratio (HR): 1.52 95% confidence interval (CI) 1.37-1.68, P<0.0001). Cohort-3 compared with Cohort-2 was not associated with lower adjusted risk for myocardial infarction/ischemic stroke (HR: 0.96, 95% CI: 0.87-1.06, P=0.44).
Conclusions: In this historical comparative study, Cohort-3 compared with Cohort-2 was associated with excess bleeding risk, which might be at least partly explained by the difference in P2Y12receptor blockers.
Keywords: Coronary artery disease; High bleeding risk; Percutaneous coronary intervention.