A new global thrombosis test (GTT) shows impaired spontaneous thrombolytic activity in elderly and in habitual smokers

Abstract number: P1284

Ikarugi^* H., Yamashita† T., Aoki† R., Ishii‡ H., Kanki^* K., Yamamoto† J.

‡Ishii Hospital, Japan †Kobe Gakuin University, Japan ^*Kobe University of Commerce, Japan;

Platelet reaction and thrombolysis are the main determinants of arterial thrombosis. Spontaneous thrombolysis is a physiological protection against the fatal outcome of an acute coronary event. Recently, a new in vitro test has been developed (GTT- Görög Thrombosis Test*) which allows the sequential assessment of all major contributors of thrombosis, i.e. platelet reactivity, coagulation and thrombolysis (Yamamoto et al. Blood Coagul. Fibrinolysis, in press). In this study we used GTT to assess the effect of age, smoking, and regular daily exercise on the thrombotic status. Sixty-four healthy males were divided into two groups: young males (n = 30; 21.1 ± 0.4 years) and old males (n = 34; 64.5 ± 1.1 years). There were 11 smokers (36.7%) in the young and 11 smokers (32.4%) in the old group. 16 young (53.3%) and 18 old (52.9%) were subjected to regular daily exercise. Platelet reactivity (Occlusion Time) and spontaneous thrombolytic activity (Lysis Time) were determined from native blood sample. Lysis times in the elderly were significantly prolonged, as compared to the young. Lysis times in elderly smokers were significantly prolonged, as compared to elderly nonsmokers. No difference in thrombolytic activity was measured between smoking and nonsmoking young. Regular exercise did not affect spontaneous thrombolysis. Platelet reactivity at rest was not affected by age, smoking or mild exercise and was inversely related to red/white cell counts, HCT, but not to platelet count. No correlation was observed between thrombolysis and blood cell counts/HCT. Impaired spontaneous thrombolysis in elderly/elderly habitual smokers may constitute a risk from acute thrombotic event. *http://www.montroseltd.net