THROMBORESISTANCE OF BULK HEPARINIZED CATHETERS IN HUMAN

Bulk heparinized catheters (1 mm internal diameter) containing 10% heparin ionically bound, were tested in four human volunteers. Catheters containing 0% and 10% heparin were compared in each individual using ultrasound microflow velocimetry, permeability test, sequential determinations of activated partial thromboplastin time, heparin level and generation of Fibrinopeptide A, .beta. thromboglobulin and Platlet factor 4. Although the release of heparin expressed by its anti-IIa activity is of similar range in the four individuals the release of anti-Xa activity is available and generally of greater magnitude, suggesting a priviledge migration of low molecular weight components of heparin. These antiproteasic activities of heparin are sufficient to inhibit fibrin formation and blood coagulation despite their relative inability to prevent platelet activation.