Platelet glycoprotein IIIa Leu33Pro gene polymorphism and coronary artery disease: A meta-analysis of cohort studies

Great interest has been focused in the last year on genetic predictors of cardiovascular risk. Glycoprotein IIb/IIIa (GP IIb/IIIa), fibrinogen receptor, is the final common pathway for aggregation and a key point for atherothrombosis. A single nucleotide polymorphism of IIIa subunit (Leu33Pro-PlA(1)/PlA(2) allele) has been suggested to increase aggregation and adhesion, however, contrasting reports have been reported so far on its effects on coronary artery disease (CAD). Aim of the current study was to perform a large meta-analysis including cohorts of patients undergoing coronary angiography in order to evaluate whether this polymorphism is associated with coronary artery disease. Literature archives (Pubmed, EMBASE, Cochrane) and main scientific sessions abstracts were scanned for data of consecutive cohorts of patients undergoing coronary angiography, where PlA genotype was assessed. Primary endpoint was the prevalence of CAD. Secondary endpoint was severity of CAD defined as prevalence of multivessel disease (>= 2 vessels). Data from seven studies were extracted, including a final number of 6700 patients. Among them 1893 (28.3%) carried the PlA(2) polymorphism, 163 of them in homozygosis. Angiographically defined CAD was present in 3573 (74.3%) PlA(1)/PlA(1) patients and in 1430 (75.5%) PlA(2) carriers. PlA(2) polymorphism was not associated with an increased prevalence of coronary artery disease, (OR [95% CI] = 1.07 [0.95-1.21], p = 0.28, pheterogeneity = 0.39). Similar results were obtained for multivessel disease (OR [95% CI] = 1.07 [0.95-1.20], p = 0.27, p(heterogeneity) = 0.12). Meta-regression analysis demonstrated a significant inverse relationship between the risk of CAD among the PlA 2 carriers and ageing (r = -0.044, (-0.09, -0.0008), p = 0.046). Present meta-analysis demonstrates that 33Leu -> Pro substitution of GPIIIa does not influence the prevalence and extent of angiographically defined coronary artery disease in general population, although apparently playing a role among younger patients.