Platelet Pl A2 polymorphism and platelet activation are associated with increased troponin I release after cardiopulmonary bypass

Abstract

Background: The Pl A2 polymorphism of platelet glycoprotein IIIa has been identified as a prothrombotic risk factor in a number of cardiovascular settings. The aim of this study was to determine whether the Pl A2 polymorphism of platelet glycoprotein IIIa and degree of platelet activation were associated with more severe myocardial injury as indicated by troponin I release following cardiopulmonary bypass. Methods: The Pl A genotype was determined in 66 patients undergoing elective coronary artery bypass grafting requiring cardiopulmonary bypass. Troponin I concentrations and the percentage of circulating, activated (CD62P+) platelets were measured at predetermined intervals perioperatively. Results: Forty-six patients were Pl A1,A1, and 20 were Pl A1,A2 or Pl A2,A2. Patients with at least one Pl A2 allele had significantly greater postoperative troponin I concentrations than Pl A1 homozygotes (P = 0.006, analysis of variance). Peak troponin I concentrations also correlated significantly with the increase in circulating, activated platelets (P = 0.02, Spearman rank correlation). Conclusions: The Pl A2 allele of platelet glycoprotein IIIa is associated with higher troponin I concentrations following cardiopulmonary bypass surgery, suggesting that this platelet polymorphism contributes to perioperative myocardial injury.