Role of soluble and platelet-bound P-selectin in discriminating cardiac from noncardiac chest pain at presentation in the emergency department

Background It has been reported that selectins participate in the pathogenesis of acute coronary syndromes by modulating platelet-leukocyte-endothelium interactions. Elevated P-selectin level also has been observed in the clinical setting of myocardial ischemia and reperfusion; however, its utility in differentiating cardiac from noncardiac origins of chest pain is unknown. Methods and Results Soluble and platelet fractions of P-selectin were measured for 122 patients with chest pain and 14 healthy persons acting as controls. Patients with a cardiac problem (unstable angina, congestive heart failure, acute myocardial infarction) had significantly elevated levels of soluble P-selectin (156.0 ± 58.8 ng/mL, P =.002) and platelet-bound P-selectin (11.7% ± 6.4% positive cells, P =.013) compared with the P-selectin profile among controls (102.6 ± 29.0 ng/mL, 4.1% ± 1.2% positivity) and among patients with noncardiac chest pain (114.7 ± 36.6 ng/mL, 5.7% ± 2.9% positivity). With a cutpoint of 10% positivity for membrane and 120 ng/mL for soluble P-selectin, the sensitivities were 0.442 and 0.558, and the specificities were 0.915 and 0.553. Conclusions When a patient arrives in the emergency department, measurement of membrane P-selectin may serve as an additional diagnostic tool to detect heightened platelet activity, which is most prevalent among patients with a cardiac origin of chest pain. However, low sensitivity limits the utility of the P-selectin profile alone in suitably differentiating acute coronary syndromes within the overall population of patients with chest pain.