Application of New Antithyombogenic Polymer (HEMA-octylstyrene Block Copolymer) to Coronary Artery Vascular Prosthesis

我们一直在研究甲基丙烯酸2-羟乙酯-苯乙烯嵌段共聚物(HEMA-St)在体内、体外和体外实验中通过抑制血小板黏附和激活而表现出良好的血液相容性。然而，HEMA-St较差的弹性体性能一直阻碍了其在冠状动脉血管假体中的应用。我们开发了一种新型的由HEMA和辛基苯乙烯组成的两亲性嵌段共聚物(HEMA-OCT)，以改善其力学性能。我们开发了一种使用HEMA-OCT的小口径血管移植物。接枝物由三层结构组成：外层为涤纶，中层为聚氨酯，内层为HEMA-OCT涂层。我们评价了5个用来替代股动脉的移植物和3个用来进行冠状动脉搭桥术的杂种犬。2例股动脉置换术8天通畅，2例冠状动脉旁路移植术8~15天通畅。扫描电子显微镜显示HEMA-OCT涂层表面无裂纹，用7-0聚丙烯缝线缝合。HEMA-OCT在保持良好血液相容性的同时，改善了弹性体的性能，具有作为冠状动脉血管假体的巨大潜力。

We have been investigating 2-hydroxyethyl methacrylate and styrene block copolymer (HEMA-st) showed excellent blood compatibility in in vivo, ex vivo, and in vitro experiments by suppressing platelet adhesion and activation. The poor elastomeric properities of HEMA-st, however, have been an obstracle to application in coronary artery vascular prosthesis. We have developed a new amphiphilic block copolymer composed of HEMA and octylstyrene ( HEMA-oct) to improve the mechanical properties. WE have developed a small caliber vascular graft using HEMA-oct. The graft consist of three layered structures : Dacron for the outer layer, polyurethane in the middle layer, and HEMA-oct coating for the inner layer. We evaluated five grafts with which femoral artery were replaced and three grafts with which coronary artery bypass grafting was performed in mongrel dogs. Two grafts for femoral artery replacement were patent in 8days and two graft for coronary artery bypass grafting were patent in 8-l5days.HEMA-oct coating layer showed no surface cracks on Scanning electron micrographs and we have easily sutured the new graft with 7-0 polypropylene suture. HEMA-oct has improved elastomeric properties while still preserving excellent blood compability and has a significant potential to be applied as a Coronary Artery Vascular Prosthesis.