When periprocedural MI was excluded , the efficacy of prasugrel remained consistent among primary and secondary PCI patients at 30 days ( HR : 0.53 ; 95 % CI : 0.34 to 0.81 vs. HR : 0.44 ; 95 % CI : 0.22 to 0.88 ; p interaction = 0.68 ) and 15 months ( HR : 0.76 ; 95 % CI : 0.56 to 1.03 vs. HR : 0.75 ; 95 % CI : 0.46 to 1.21 ; p interaction = 0.96 ) .