However , a tendency toward a difference in treatment effect at 30 days ( HR : 0.68 ; 95 % CI : 0.54 to 0.87 ; p = 0.002 ) was observed between primary and secondary PCI patients ( HR : 0.81 ; 95 % CI : 0.60 to 1.09 vs. HR : 0.51 ; 95 % CI : 0.34 to 0.76 ; p interaction = 0.06 ) .