β-Thromboglobulin, Platelet Production Time and Platelet Function in Vascular Disease

Abstract
Plasma .beta.-thromboglobulin (.beta.TG) levels were measured in 103 healthy controls and 112 patients with peripheral vascular disease (PVD), cerebrovascular disease (CVD) or deep vein thrombosis (DVT). Plasma .beta.TG was significantly elevated in 46 PVD patients and 24 recent DVT patients compared to controls, but did not differ significantly in 18 chronic DVT and 24 patients with history of CVD. Heparin neutralizing activity (HNA) and platelet aggregation induced by ADP, L-epinephrine and thrombin were compared in 33 of 46 PVD patients to 33 controls. The mean HNA was significantly shorter in the PVD patients than in controls. The rate and extent of platelet aggregation were increased in PVD patients compared to controls, but difference was not statistically significant. Platelet production time (PPT) was measured in 20 controls, 35 PVD patients, 9 chronic DVT and 12 chronic CVD patients; significantly shorter PPT was only observed in 14 patients with advanced PVD compared to controls, suggesting increased platelet consumption in these patients. All 4 assays (plasma .beta.TG, HNA, platelet aggregation and PPT) were performed in 25 patients; no correlation between the 4 tests occurred, suggesting that tests were measuring different aspects of platelet function. In vivo platelet consumption and platelet aggregation and release reaction are presumably enhanced in PVD and recent DVT patients and plasma .beta.TG and PPT assays may be better and more specific indicators of in vivo platelet activation than in vitro platelet aggregation test.