Point-of-care determination of baseline platelet function as a predictor of clinical outcomes in patients who present to the Emergency Department with Chest Pain

Background: Increased platelet reactivity can identify patients at high risk for thrombotic events, but its clinical use has been impractical due to technical limitations. The purpose of the present study is to determine if a point-of-care measurement of platelet function in patients presenting to an emergency room with chest pain can identify those at high risk of adverse cardiac events. Methods: Platelet function was measured using the Ultegra-RPFA in 201 patients presenting to the emergency department with the primary complaint of chest pain and either known coronary disease or at least one cardiac risk factor. The primary endpoint was any major adverse cardiac events (MACE) [cardiac death, myocardial infarction (MI), re-admission for coronary revascularization] 6 months post-enrollment. Results: Platelet function at baseline ranged from 44 to 315 platelet activation units (PAU) (mean 175±6). Seventy-six patients experienced MACE (37.8%) by 6 months post-enrollment. Mean PAU was significantly lower in the group experiencing MACE (166±9 vs. 181±9; p = 0.026). By univariate analysis, admission PAU was a significant predictor of MACE at 6 months (p = 0.028). However, when adjusted for age, gender, cardiac risk factors, and a history of coronary artery disease (CAD) using multivariate logistic regression analysis, PAU was no longer significantly predictive of MACE (p = 0.268). Conclusions: Point-of-care testing of platelet function deserves further study for risk assessment and individualized therapy in the future. Abbreviated Abstract. Platelet function was assessed in 201 patients presenting to the emergency department with chest pain using a point-of-care device to measure platelet activation, the Ultegra-RPFA. Platelet function, expressed in platelet activation units (PAU), was significantly lower in patients who experienced adverse cardiac events (p = 0.026). By univariate analysis, PAU was a significant predictor of cardiac death, MI, and re-hospitalization for revascularization at 6 months (p = 0.028). However, when adjusted for age, gender, cardiac risk factors, and coronary artery disease (CAD), PAU was no longer significantly predictive of the above combined endpoint (p = 0.268).