Competing risks of major bleeding and thrombotic events with prasugrel-based dual antiplatelet therapy after stent implantation - An observational analysis from BASKET-PROVE II

BACKGROUND: Dual antiplatelet therapy (DAPT) prevents thrombotic events after coronary stent implantation but may induce bleedings, specifically in elderly patients. However, a competitive risk analysis is lacking. OBJECTIVES: To assess the determinants of major bleeding and the balance between the competing risks of major bleeding and thrombotic events during prasugrel-based DAPT after stent implantation. METHODS: Overall, 2,291 patients randomized to drug-eluting or bare metal stents and treated with prasugrel 10mg/day for 1 year were followed over 2 years for major bleeding (BARC 3/5) and thrombotic events (cardiac death, myocardial infarction, definitive/probable stent thrombosis). Prasugrel dose was reduced to 5mg in patients >75 years and/or <60kg. Predictors of major bleeding and competing risks of major bleeding and thrombotic events were assessed. RESULTS: Two-year rates of major bleeding and thrombotic events were 2.9% and 9.0%, respectively. The only independent predictor of major bleeding was age (hazard ratio per year increase 1.05 [1.02,1.07], p<0.001). The relationship between major bleeding and age was non-linear, with lowest hazard ratios at 57 years and an exponential increase only above 65 years. In contrast, the relationship between thrombotic events and age was linear and continuously increasing with older age. While the competing risk of thrombotic events was higher than that of major bleeding in younger patients, the two risks were similar in older patients. After discontinuation of prasugrel, bleeding events leveled off in all patients, while thrombotic events continued to increase. CONCLUSIONS: In prasugrel-based DAPT, age is the strongest risk factor for major bleeding, increasing exponentially >65 years. In younger patients, thrombotic events represent a higher risk than bleeding, while thrombotic and bleeding risks were similar in older patients. Important clinical implications relate to prasugrel dose in the elderly, duration of DAPT and the competing risk balance necessitating individualized treatment decisions.