After RBC transfusion , platelet reactivity was increased when measured using adenosine diphosphate-induced light transmission aggregometry ( @ % relative increase in maximal platelet aggregation , p = @ ; @ % increase in residual platelet aggregation , p = @ ) and vasodilator-stimulated phosphoprotein platelet reactivity index ( @ % relative increase , p = @ ) , and there was a nonsignificant trend toward an increase in P-selectin expression .