Evaluation of the antithrombogenicity of a new microdomain structured copolymer

A new antithrombogenic material was studied, fluorine-acryl-styrene-urethane-silicone (FASUS) copolymer, the theoretical basis of which attributed to its hydrophilic and hydrophobic microdomain structure. In this series of experiments, the blood compatibility of this copolymer was evaluated in vitro and ex vivo. For the in vitro evaluation, a whole blood clotting test and the microsphere column test were performed. For the ex vivo evaluation, two series of shunt tests in rabbits were performed, one was the arterioartery (A-A) shunt model, and the other was the arteriovenous (A-V) shunt model. The antithrombogenicity was assessed by measuring the shunt obstructive time in the A-A shunt experiment. The A-V shunt experiment was assessed by measuring the circulating platelet counts, platelet aggregability, activated partial thromboplastin time (APTT), and prothrombin time (PT). In the whole blood clotting test, FASUS revealed the significantly longer blood clotting time than that of the control glass tubings (19.7 +/- 1.0 versus 6.5 +/- 0.7 min, p < 0.001). In the microsphere column test, the coated group had a 30% reduction of the platelet number in the eluted blood in contrast with a marked decrease of 70% in the control group (p < 0.05). In the ex vivo A-A shunt experiment, the occlusion time for the FASUS-coated group was significantly longer than that of the control (109.7 +/- 17.3 versus 3.0 +/- 0.4 min, p < 0.05). The A-V shunt experiment showed that the FASUS copolymer suppressed the decrease in platelet counts and tended to improve prolonged APTT compared with that of the control. Clinically, in 25 patients, we placed coated FASUS copolymer into the cannulas for use in percutaneous cardiopulmonary support (PCPS) procedures. There was no evidence of thrombus on the blood contacting surface and no thromboembolism in major organs clinically or upon postmortem examination. In summary, this new copolymer may be effective in preventing thrombus formation in vitro, ex vivo, and in clinical situations.