Prior Antiplatelet Use and Cardiovascular Outcomes in Patients Presenting with Acute Coronary Syndromes

Although antiplatelet therapy effectively reduces ischemic events, the cardiovascular (CV) outcome in some cases is still unpredictable. The objective of this study was to evaluate the impact of prior single or dual antiplatelet (PAP) use in patients presenting with acute coronary syndromes (ACS). Data were collected from the 2nd Gulf Registry of Acute Coronary Events between October 2008 and June 2009. Patients were grouped according to whether they were PAP users or not (NAP). Patients’ characteristics and outcomes were analyzed and compared. Mortality was assessed at 1 and 12 months. Among 7827 consecutive ACS patients, 41% were PAP users (70% aspirin, 1% clopidogrel, and 29% dual antiplatelet agents). In comparison with NAP use, PAP use was associated with a higher rate of comorbidities, atypical presentation, severe left ventricular dysfunction, three-vessel disease, and a high GRACE risk score. After adjustment for relevant covariates, PAP use was an independent predictor for recurrent ischemia in unstable angina (odds ratio [OR] 1.7; 95% CI 1.17, 2.57) and non-ST-elevation myocardial infarction (NSTEMI) [OR 1.9; 95% CI 1.38, 2.65] and for heart failure in NSTEMI (OR 1.5; 95% CI 1.11, 2.15) and STEMI (OR 1.4; 95% CI 1.08, 1.93). Although PAP use was associated with high mortality in STEMI and NSTEMI, it was not an independent predictor for mortality. Among PAP patients, percutaneous coronary intervention independently reduced the risk of hospital (adjusted OR 0.25; 95% CI 0.20, 0.32), 1-month (OR 0.31; 95% CI 0.26, 0.37), and 12-month mortality (OR 0.28; 95% CI 0.24, 0.33). PAP use identified a high-risk population across the ACS spectrum. Early coronary revascularization may improve CV outcomes in these patients.