Background: Coronary stents are an effective treatment for selected coronary stenoses. However, thrombosis of the stented segment is a major adverse complication. Platelet aggregation has a key role in stent thrombosis. We investigated whether a polymorphism of platelet glycoprotein IIIa gene (PIA2) is associated with an increased risk of coronary stent thrombosis.
Methods: 318 consecutive patients were followed up for 30 days after coronary stent insertion. The primary endpoints were death, myocardial infarction, stent-vessel occlusion, and coronary artery bypass surgery. Gel electrophoresis of PCR products was used to identify the PIA1 and PIA2 alleles. The relative risk of stent occlusion was calculated from the odds ratio on logistic regression analysis.
Findings: 63 (19.8%) of patients had the PIA2 allele and 255 (80.2%) were 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 ratio 5.26 [95% CI 1.55-17.85]). On multivariate regression analysis PIA1/A2 genotype was the only significant independent predictor of stent thrombosis.
Interpretation: Patients with the pIA2 allele have an increased risk of coronary stent thrombosis, which may warrant antiplatelet therapy with glycoprotein-IIb/IIIa inhibitors, although bleeding complications may also increase.