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 acute myocardial infarction (AMI) therapy. We sought to determine whether the degree of pre-reperfusion platelet function is related to subsequent activity 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 revealed a significant correlation for 5 μM ADP (r² = 0.529), 10 μM ADP (r² = 0.445), thrombin (r² = 0.226), collagen (r² = 0.568), and ristocetin-induced aggregation (r² = 0.964). Platelet expression linearly correlated for GPIIb/IIIa (r² = 0.337), P-selectin (r² = 0.817), PECAM-1 (r² = 0.586), and the vitronectin receptor (r² = 0.634). The data suggest that the baseline characteristics predict future platelet activity, and may prospectively identify patients who will benefit most from antiplatelet strategies after coronary thrombolysis.