Nagae T, Tsuchida H, Peng S K, Furukawa K, Wilson S E
Department of Surgery, University of California, Irvine Medical Center, Orange, USA.
Cardiovasc Surg. 1995 Oct;3(5):479-84. doi: 10.1016/0967-2109(95)94445-3.
Polytetrafluoroethylene (PTFE) prostheses were modified to produce two types of composite porosity PTFE grafts: type I--inner 60 microns/outer 20 microns and type II--inner 20 microns/outer 60 microns. These composite porosity PTFE designs were investigated for bleed through, graft healing and patency and compared with high porosity PTFE (60 microns) and standard PTFE (20 microns) grafts. The grafts were implanted into the carotid and femoral arteries of dogs and retrieved after 4, 12 and 18 weeks. Both composite porosity grafts showed significantly less bleed through than standard and high porosity grafts after reperfusion. In composite grafts, the 60-microns layer allowed fibrovascular tissue and histiocyte ingrowth from perigraft tissue, but the 20-microns layer did not. Neointima formation occurred earlier and endothelialization was more extensive in high porosity grafts, but seroma formation occurred in 25% of cases. In type I composite porosity grafts, smooth muscle cells of neointima migrated into the pores of the graft, providing a firmly anchored intima. Type II composite porosity grafts allowed better ingrowth of fibrovascular tissue at the outer layer from the perigraft tissue; however, endothelialization was not completed. Composite porosity grafts should be considered for evaluation in specific clinical situations.
聚四氟乙烯（PTFE）假体经过改性，制成了两种复合孔隙率的PTFE移植物：I型——内层60微米/外层20微米，II型——内层20微米/外层60微米。对这些复合孔隙率PTFE设计进行了渗血、移植物愈合和通畅性研究，并与高孔隙率PTFE（60微米）和标准PTFE（20微米）移植物进行了比较。将移植物植入犬的颈动脉和股动脉，并在4周、12周和18周后取出。再灌注后，两种复合孔隙率移植物的渗血均明显少于标准移植物和高孔隙率移植物。在复合移植物中，60微米层允许纤维血管组织和组织细胞从移植物周围组织向内生长，但20微米层则不允许。高孔隙率移植物中内膜形成较早，内皮化更广泛，但25%的病例出现了血清肿形成。在I型复合孔隙率移植物中，内膜的平滑肌细胞迁移到移植物的孔隙中，形成牢固附着的内膜。II型复合孔隙率移植物允许纤维血管组织从移植物周围组织更好地向内生长到外层；然而，内皮化未完成。在特定临床情况下，应考虑对复合孔隙率移植物进行评估。
