Relationship between post‐treatment platelet reactivity and ischemic and bleeding events at 1‐year follow‐up in patients receiving prasugrel

Summary.  Background:  Post‐treatment platelet reactivity (PR) is associated with ischemic and bleeding events in patients receiving P2Y12 receptor antagonists. Objectives:  We aimed to study the relationship between post‐treatment PR after a 60‐mg loading dose (LD) of prasugrel and 1‐year thrombotic and bleeding events. Method:  Patients were prospectively included in this multicenter study if they had a successful percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) and received prasugrel. The platelet reactivity index (PRI) was measured using the Vasodilator‐Stimulated Phosphoprotein index (VASP) after a prasugrel LD. Endpoints included the rate of thrombotic events and bleeding events at 1 year. Results:  Among the 301 patients enrolled, 9 (3%) were lost to follow‐up at 1 year. The rates of thrombotic and bleeding events at 1 year were of 7.5% and 6.8%, respectively. Receiver‐operating curve (ROC) analysis demonstrated an optimal cut‐off value of 53.5% of PRI to predict thrombotic events at 1 year. Using this cut‐off value we observed that patients exhibiting high on‐treatment platelet reactivity (HTPR) had a higher rate of thrombotic events (22.4% vs. 2.9%; P  <   0.001). In parallel the optimal cut‐off value of PRI to predict bleeding was 16%. Patients with a PRI ≤ 16% had a higher rate of bleeding events compared with those with a PRI > 16% (15.6% vs. 3.3%; P  <   0.001). In multivariate analysis, the PRI predicted both thrombotic and bleeding events (OR: 1.44, 95% confidence interval [CI]: 1.2–1.72; P  <   0.001 and OR: 0.75, 95% CI: 0.59–0.96; P  =   0.024 [respectively, per 10% increase]). Conclusion:  Platelet reactivity measurement after a prasugrel LD predicts both ischemic and bleeding events at 1 year follow‐up for ACS patients undergoing PCI.