Guillaume Cayla, M.D., Ph.D., of the University of Paris, and colleagues studied the platelet reactivity and rate of 30-day bleeding events in patients treated with percutaneous coronary intervention and prasugrel 10 mg/day after ACS. Platelet reactivity was monitored using three different tests: the vasodilator-stimulated phosphoprotein (VASP) index, the VerifyNow P2Y12 assay, and light transmission aggregometry.The researchers found that HPR was seen in 6.8, 3.4, and 3.2 percent of patients using the VASP, P2Y12, and residual platelet reactivity definitions, respectively. Obesity and multivessel disease were significantly and independently associated with HPR. No major bleeding complications were observed at 30 days, and 1.6 percent of patients had recurrent ischemic events. Overall, 14.2 percent of patients experienced nuisance bleeding and 2.5 percent experienced minor bleeding episodes, neither of which were predicted by VASP index.