Platelet adhesion in patients prone to arterial and venous thrombosis: the impact of gender, smoking and heredity.

Platelet adhesion was measured in 271 consecutive subjects (151F, 120M) referred to the department for investigation of their propensity to develop thrombosis. Arterial thrombosis was the cause in 27% of the subjects and pulmonary embolism in 23%, whereas venous thrombosis was the cause in 50%. Ninety-three patients were using nicotine in the form of smoking or snuffing, 45 were ex-users and 130 patients never-users. Adhesion was measured as the retention of platelets in a commercially available column of glass beads. After strict standardization of the method the reproducibilities within-day and between-day were good. Platelet retention was increased in thrombosis-prone patients as compared to references (p=0.016). This increase was seen irrespective of type of thrombosis. Multifactor ANOVA analysis revealed a strong dependence of gender and smoking habits with higher platelet retention in men and in ex-smokers and current smokers. The highest levels were found in ex-smokers with arterial thrombosis and in current smokers with pulmonary embolism. In the control population we found high platelet retention in smokers (p=0.001) and in those with a family history of thrombosis (p=0.0025). It is concluded that the measurement of platelet retention may form a basis for the selection of patients to antiplatelet therapy and that the activity of platelets is affected by smoking and related to sex and family history of thrombosis. It is also concluded that thrombus formation in men and women may be governed partly by different mechanisms.