Walpoth B H, Rogulenko R, Tikhvinskaia E, Gogolewski S, Schaffner T, Hess O M, Althaus U
Department of Thoracic and Cardiovascular Surgery, University Hospital, Inselspital, Bern, Switzerland.
Circulation. 1998 Nov 10;98(19 Suppl):II319-23; discussion II324.
Graft thrombosis and intimal hyperplasia represent the major causes of graft failure. Heparin has been shown to have a beneficial effect on long-term patency and on prevention of intimal hyperplasia. Thus, the purpose of the present study was to evaluate the effect of heparin coating on patency rate and intimal hyperplasia in small synthetic vascular grafts.
Two synthetic grafts (expanded polytetrafluoroethylene [ePTFE], and polyurethane) with and without heparin coating were implanted in the infrarenal aorta (diameter, 2 mm) of 40 Whistar rats. Animals survived 8 weeks after implantation. Graft patency, intimal thickness, and percentage of diameter stenosis were determined by light microscopy at the proximal respectively distal anastomosis and in the middle of the graft. Uncoated grafts showed a patency rate of 70% for ePTFE and 60% for polyurethane grafts. Heparin-coated grafts showed a patency rate of 100% for ePTFE and 90% for polyurethane grafts. Intimal hyperplasia was observed in all grafts mainly at the anastomosis site. Intimal wall thickness and percentage of stenosis were significantly more pronounced in the polyurethane than ePTFE grafts (P < 0.01). Heparin coating significantly reduced overall graft thrombosis (P < 0.05) but had no significant effect on intimal hyperplasia.
Small grafts show a high rate of graft thrombosis and an enhanced intimal hyperplasia. ePTFE grafts show significantly less intimal hyperplasia and percentage of stenosis than polyurethane grafts. Heparin coating significantly reduced graft thrombosis but had no significant effect on intimal hyperplasia. Thus, heparin coating seems to be beneficial for graft patency, and ePTFE appears to be superior to polyurethane as graft material.
移植物血栓形成和内膜增生是移植物功能衰竭的主要原因。肝素已被证明对长期通畅率和预防内膜增生具有有益作用。因此，本研究的目的是评估肝素涂层对小型合成血管移植物通畅率和内膜增生的影响。
将有无肝素涂层的两种合成移植物（膨体聚四氟乙烯[ePTFE]和聚氨酯）植入40只Wistar大鼠的肾下腹主动脉（直径2mm）。动物在植入后存活8周。通过光学显微镜在近端和远端吻合口以及移植物中部测定移植物通畅率、内膜厚度和直径狭窄百分比。未涂层的ePTFE移植物通畅率为70%，聚氨酯移植物为60%。肝素涂层的ePTFE移植物通畅率为100%，聚氨酯移植物为90%。在所有移植物中均观察到内膜增生，主要位于吻合口部位。聚氨酯移植物的内膜壁厚度和狭窄百分比明显比ePTFE移植物更显著（P<0.01）。肝素涂层显著降低了总体移植物血栓形成（P<0.05），但对内膜增生无显著影响。
小型移植物显示出较高的移植物血栓形成率和增强的内膜增生。ePTFE移植物的内膜增生和狭窄百分比明显低于聚氨酯移植物。肝素涂层显著降低了移植物血栓形成，但对内膜增生无显著影响。因此，肝素涂层似乎有利于移植物通畅，并且ePTFE作为移植物材料似乎优于聚氨酯。
