Baseline platelet aggregation and major receptor expression predict subsequent activity following thrombolysis for acute myocardial infarction

The early identification of patients with heightened platelet activity for aggressive antiplatelet regimens represents a critical clinical issue in ac ute myocardial infarction (AMI) therapy. We sought to determine whether the degree of pre-reperfusion platelet function is related to subsequent activ ity following thrombolysis. Platelets were investigated at baseline and at 24 h following thrombolytic therapy by aggregometry, and flow cytometry in 19 AMI patients enrolled in the GUSTO-III trial. Regression analysis reveal ed a significant correlation for 5 mu M ADP (r(2)-0.529), 10 mu M ADP (r(2) =0.445), thrombin (r(2) = 0.226), collagen (r(2) = 0.568), and ristocetin-i nduced aggregation (r(2) - 0.964). Platelet expression linearly correlated for GPIIb/IIIa (r(2) = 0.337), P-selectin (r(2) = 0.817), PECAM-1 (r(2) = 0 .586), and the vitronectin receptor (r(2) = 0.634). The data suggest that t he baseline characteristics predict future platelet activity, and may prosp ectively identify patients who will benefit most from antiplatelet strategi es after coronary thrombolysis.