Measurement of platelet loss in the blood compatibility assessment of biomaterials

Abstract

In the assessment of the in vitro blood compatibility of biomaterials, platelet loss is often attributed solely to platelet adhesion and consideration is not given to platelets lost in platelet aggregate formation. In order to distinguish between those platelets lost to adhesion and those lost to aggregate formation, the Wu and Hoak method for the quantification of circulating platelet aggregates in patients has been modified to establish a new test procedure. This procedure, which measures both platelet adhesion (PA) in the absence of platelets lost to aggregate formation and also the tendency of a material to induce aggregate formation, has been used to evaluate the influence of a range of polyamides and a hydrogel. The evaluation demonstrated the ability of polymers to induce readily platelet aggregates during in vitro blood-material contact. The sensitivity of the aggregate measurement was exemplified by the polyamides, where PA was similar for materials of different porosity but platelet aggregate formation increased significantly with porosity. The importance of considering platelets lost to aggregate formation was emphasized with the hydrogel, where PA was low. © 1987.