Association of the Plasminogen Activator Inhibitor-1 Gene 4G/5G Polymorphism With ST Elevation Acute Myocardial Infarction in Young Patients

Introduction and objectives. To investigate the role of the 4G/5G polymorphism in the plasminogen activator inhibitor-1 (PAI-1) gene in patients with ST-elevation myocardial infarction (STEMI) aged <= 45 years and its influence on regulation of the plasma PAI-1 concentration. Methods. This case-control study included 127 consecutive patients aged <= 45 years with a diagnosis of STEMI who were admitted to a cardiovascular intensive care unit and 127 controls recruited between January 2006 and March 2007. Participants were genotyped for the 4G/5G polymorphism using the polymerase chain reaction and restriction fragment length polymorphism analysis, and their plasma PAI-1 concentrations were measured. Informed consent was obtained from all participants. Results. There was a significant difference in genotype distribution between the two groups (P<.002). The 4G allele occurred more frequently in the patient group (P=.032). In addition, there were significant independent associations between STEMI and the 4G allele (i.e., 4G/4G plus 4G/5G; odds ratio [OR]=2.29; 95% confidence interval [CI], 1.12-4.68; P=.022), smoking (OR=23.23; 95% CI, 8.92-60.47; P<.001), a family history of cardiovascular disease (OR=4.66; 95% CI, 2.06-10.52; P=.001) and hypertension (OR=5.42; 95% CI, 1.67-17.56; P=.005). The plasma PAI-1 concentration was higher in individuals who were homozygous for the 4G allele (P<.001). Conclusions. The study findings indicate that the 4G allele is an independent risk factor for acute myocardial infarction in young patients, as are smoking, hypertension and a family history of inherited cardiovascular disease.