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.