PLATELET GLYCOPROTEIN IIIA POLYMORPHISMS AND RISK OF CORONARY STENT THROMBOSIS

Background Coronary stents are an effective treatment for selected cor onary stenoses. However, thrombosis of the stented segment is a major adverse complication. Platelet aggregation has a key role in stent thr ombosis. We investigated whether a polymorphism of platelet glycoprote in IIIa gene (PIA2) Is associated with an increased risk of coronary s tent thrombosis. Methods 318 consecutive patients were followed up for 30 days after coronary stent insertion. The primary endpoints were de ath, myocardial infarction, stent-vessel occlusion, and coronary arter y bypass surgery. Gel electrophoresis of PCR products was used to iden tify the PIA1 and PIA2 alleles. The relative risk of stent occlusion w as calculated from the odds ratio on logistic regression analysis. Fin dings 63 (19.8%) of patients had the P1(A2) allele and 255 (80.2%) wer e homozygous for PIA1. Baseline clinical, angiographic, and procedural features did not differ between the groups with and without the PIA2 allele. Occlusion of the stent vessel occurred in five (1.9%) patients homozygous for PIA1 and six (9.5%) patients with PIA2 allele (odds ra tio 5.26 [95% CI 1.55-17.85]). On multivariate regression analysis PIA 1/A2 genotype was the only significant independent predictor of stent thrombosis. Interpretation Patients with the PIA2 allele have an incre ased risk of coronary stent thrombosis, which may warrant antiplatelet therapy with glycoprotein-IIb/IIIa inhibitors, although bleeding comp lications may also increase.