Improved Test Procedures for the Hemocompatibility Evaluation of Biomaterials.

摘要

The ex vivo (canine) hemocompatibility of biomaterials was evaluated under the experimental conditions of the Stagnation Point Flow Experiment (SPFE). The relative thromboresistance of each material was assessed under controlled and systematically varied hemodynamic conditions. A clear differentiation is shown between thromboembolic phenomena that arise as a result of flow--disturbing surface nonuniformities and those which arise,under fixed hemodynamics,as a function of the molecular structure of materials. A relative ranking of thromboresistance,according to each of the SPFE criteria,is given for all materials whose evaluation has been completed. The development of the intra-aortic Magnetic Suspension of a Test Device for evluation of in vivo (canine) hemocompatibility of biomaterials was continued. The system hardware capability was increased,and stable operation was achieved under strongly pulsatile aortic flow conditions simulated in a Circulation Model. Sensitivity to detect thrombus growth under idealized conditions was established. The adequacy of the overall surgical procedure was demonstrated and the in vivo feasibility of the test procedure was confirmed during acute in vivo trials.