Thrombocyte activation increases with the degree of carotid artery stenosis

Abstract

Thrombocyte activation and subsequent aggregate formation play a pivotal role in arterio-arterial embolism in high grade carotid artery stenosis. The aim of this study was to test the hypothesis that the amount of activated thrombocytes would differ with the degree of stenosis. In 19 patients with asymptomatic carotid artery stenosis > 70%, 11 patients with low grade carotid disease and a luminal narrowing of < 70%, and 13 healthy controls in vivo thrombocyte activation was determined by the surface thrombocyte expression of P-selectin before and after thrombin stimulation by whole blood flow cytometry. Soluble P (sP)-selectin in serum was measured by ELISA. We found that thrombocyte activation significantly increased with the degree of stenosis in a multiple correlation analysis corrected for age, sex, and cardiovascular risk factors. Only thrombocyte P-selectin expression and sP-selectin serum concentrations were able to discriminate the patient groups in a multivariate analysis, however, only thrombocyte P-selectin expression was an independent variable. In vivo thrombocyte activation, then, increases with the degree of carotid stenosis. Flow cytometry is especially useful in the evaluation of the thrombocyte activation state in patients with cerebrovascular disease.