Platelet half-life, plasma thromboxane B2 and circulating endothelial-cells in peripheral vascular disease.

We studied platelet half-life (T/2), plasma thromboxane B2-levels (TXB2) and circulating endothelial cells in 107 patients with a mean age of 63 +/- 6.8 years and angiographically proven peripheral vascular disease (PVD). Patients were divided into 4 groups according to Fontaine but also according to additional clinical manifestations of atherosclerosis like coronary heart disease (CHD) and cerebrovascular disease (CVD). Furthermore, the influence of sex and smoking was investigated. Compared to patients without atherosclerotic manifestations we could detect an enhanced platelet consumption measured as shortened platelet half-life time (79.2 +/- 9.1 vs 100.9 +/- 5.6 hours, p less than 0.001 and an increased platelet activity measured as increased TXB2-plasma levels (51.6 +/- 20.9 vs 23.2 +/- 11.2 ng/ml, p less than 0.001). Correspondingly, the amount of circulating endothelial cells was increased 45.2 +/- 25.7 vs 20.3 +/- 23.4, p less than 0.001). Patients with PVD who smoked had the shortest actual platelet half-life, the highest TXB2 plasma levels and the greatest amount of circulating endothelial cells compared to non-smoking patients and controls. Patients with clinical stage IV according to Fontaine had the shortest platelet half-life, the highest TXB2 plasma levels and the greatest amount of circulating endothelial cells compared to the other clinical stages. Analyzing the influence of additional clinical manifestations of atherosclerosis we could detect only in patients with PVD and CHD significant differences compared to the other groups.