PI^A polymorphism of glycoprotein IIIa and efficacy of reperfusion therapy in patients with acute myocardial infarction

The PI^A polymorphism of the platelet glycoprotein IIIa gene is associated with altered platelet function and response to antiplatelet drugs. We sought to assess whether the PI^A polymorphism influences myocardial salvage achieved by reperfusion therapy in patients with acute myocardial infarction. We analyzed 292 patients enrolled in 2 randomized trials that compared stenting plus abciximab with thrombolysis (alteplase alone or alteplase plus abciximab) in acute myocardial infarction. Patients were genotyped for the PI^A polymorphism using polymerase chain reaction with fluorogenic probes. Technetium-99m sestamibi was injected before and 1-2 weeks after reperfusion treatment. The scintigrams enabled the calculation of the initial perfusion defect, final infarct size, and the proportion of initial defect salvaged by reperfusion (salvage index). Clinical follow-up was done up to 18 months after primary treatment. The genotype distribution was as follows: PI^A2/^A2 in 3.4%, PI^A1/^A2 in 24.7% and PI^A1/^A1 in 71.9% of patients. There were no significant differences between PI^A2 allele carriers and PI^A1/^A1 patients in salvage index (0.46±0.50 vs. 0.41±0.43, respectively, P=0.48), final infarct size (16.8±20.8% vs. 18.4±19.1% of left ventricle, respectively, P=0.46) as well as 18-month mortality (8.5% vs. 7.1%, respectively, P=0.69). The lack of relationship between PI^A2 allele and myocardial salvage was observed for both reperfusion strategies, stenting and thrombolysis. Thus, these findings show that the functional PI^A polymorphism of platelet glycoprotein IIIa has no influence on the degree of myocardial salvage achieved by reperfusion therapies in patients with acute myocartiial infarction.