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

我们一直在研究2-羟乙基甲基丙烯酸酯和苯乙烯嵌段共聚物（HEMA-st）在体内、体外和体外实验中通过抑制血小板粘附和活化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是冠状动脉血管假体应用的障碍。为了提高材料的力学性能，我们研制了一种由HEMA和辛苯乙烯组成的新型两亲性嵌段共聚物（HEMA-oct）。我们利用HEMA-oct开发了一种小口径血管移植物。接枝材料由三层结构组成：外层为涤纶，中间层为聚氨酯，内层为HEMA-oct涂层。我们评估了在杂种犬中进行的5例股骨动脉置换和3例冠状动脉旁路移植术。2例股动脉置换术在8d内通畅，2例冠状动脉旁路移植术在8- 15 d内通畅。扫描电镜显示，HEMA-oct涂层表面无裂纹，用7-0聚丙烯缝线轻松缝合。HEMA-oct具有改进的弹性性能，同时仍保持良好的血液相容性，具有应用于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.