SHEAR-INDUCED FILTER BLOCKAGE - A POPULATION-BASED APPRAISAL OF A METHOD FOR THE ASSESSMENT OF PLATELET, WHITE CELL AND VON-WILLEBRAND-FACTOR INTERACTIONS

Blood behaviour under shear-stress is assessed by a filter method in t he Caerphilly Prospective Heart Study. Associations with haemostatic a nd lifestyle factors in 941 men aged 55 to 69 years are reported. The importance of platelets in filter blockage is confirmed, and roles for white cells and plasma viscosity in determining flow prior to blockag e are identified. The aspect of platelet activity involved in blockage appears to be independent of mechanisms mediated by cyclo-oxygenase a nd adenosine diphosphate. von Willebrand factor however is associated with filter blockage, probably as an inter-platelet ligand. Fibrinogen is not required for blockage. Men regularly consuming alcohol or garl ic supplements show reduced blockage, and biochemical mechanisms are s uggested which might explain these associations. No effects of aspirin , smoking or consumption of fish oil supplements were noted. Shear-ind uced filter blockage is a simple method for measuring complex flow-dep endent interactions of haemostatic factors. Its application in a wide range of investigations, including epidemiological studies. would appe ar to be appropriate.