Intrinsic platelet reactivity before P2Y12 blockade contributes to residual platelet reactivity despite high-level P2Y12 blockade by prasugrel or high-dose clopidogrel. Results from PRINCIPLE-TIMI 44 - Frelinger, AL, 3rd; Michelson, AD; Wiviott, SD (Thromb Haemost, 2011)