INITIAL INTERACTIONS OF PLATELETS AND PLASMA-PROTEINS IN FLOWING NONANTICOAGULATED HUMAN BLOOD WITH THE ARTIFICIAL SURFACES DACRON AND PTFE

The purpose of the present study was to investigate and to compare the interactions of platelets and proteins in flowing non-anticoagulated human blood with the biomaterials polyethylene-terephthalate (Dacron) and polytetrafluoroethylene (PTFE, Teflon). The respective biomaterial s were positioned in a parallel-plate perfusion chamber, and exposed t o flowing blood for 5 min at wall shear rates characteristic for veins (100/s), medium sized (650/s) and moderately stenosed arteries (2600/ s). Blood-material interactions were morphologically quantified as pla telet-surface adhesion, thrombus volume and fibrin deposition. Platele t adhesion to Dacron was highest at the lowest shear rate (13%) and de creased with increasing shear (4% at 2600/s). In contrast, platelet ad hesion to PTFE was shear rate independent (17-19%), and significantly higher than the adhesion to Dacron at 2600/s (P< 0.05). A hallmark of the platelets adherent to PTFE and Dacron was the large percentage of platelets not spread out on the surface. This indicates that both mate rials were poor platelet activators, even though immunostaining demons trated the adsorption of the platelet adhesive proteins von Willebrand factor and fibronectin. Adsorption of fibrinogen was also prevailing on both materials. Virtually no thrombi formed on Dacron, while a few small platelet thrombi were observed on PTFE. Less than 1 % of the Dac ron and PTFE surfaces were covered by fibrin, irrespective of the shea r rate. Thus, Dacron and PTFE interact differently with flowing non-an ticoagulated human blood, and Dacron is apparently the least thromboge nic material.