Noishiki Y, Tomizawa Y, Yamane Y, Okoshi T, Satoh S, Matsumoto A
First Department of Surgery, Yokohama City University, School of Medicine, Japan.
J Thorac Cardiovasc Surg. 1993 May;105(5):796-804.
We have previously demonstrated rapid and complete endothelialization in synthetic fabric vascular prostheses that have been pretreated with autologous venous tissue fragments. However, significant thrombogenicity has been a major problem when this method has been applied to small-diameter grafts. By masking the positively charged collagen fibrils in the tissue fragments with negatively charged heparin, we were able to overcome this problem. A canine jugular vein was resected, minced into tissue fragments, and suspended. This mixture was sieved through the wall of a highly porous vascular prosthesis with a water porosity value of 4,000 ml/cm2 per minute by pressurized injection, which caused the tissue fragments to be trapped in the graft wall. Tissue-fragmented grafts (7 mm inside diameter, 5.7 cm long) were implanted into the thoracic aorta of 35 dogs. In addition, tissue-fragmented grafts of small diameter (4 mm inside diameter, 3.5 cm long) were pretreated with heparin and implanted into the carotid arteries of 16 dogs (32 grafts). Preclotted grafts without tissue fragmentation were implanted into the thoracic aorta (25 dogs) and carotid arteries (6 dogs, 12 grafts) as controls. Grafts were explanted from 1 to 495 days after implantation. New arterial wall formation was complete throughout the tissue-fragmented grafts within 2 weeks; however, in the control grafts, neointima formation was limited to the anastomotic sites even after 2 months. Twenty small-caliber tissue-fragmented grafts that were pretreated with heparin in the carotid position were patent, but all the control grafts were occluded within 1 week. These results demonstrate that neointima formation can be enhanced in synthetic fabric prostheses; furthermore, long-term patency of vascular grafts of small caliber is possible in dogs with this tissue-fragmentation technique.
我们之前已经证明，在经过自体静脉组织碎片预处理的合成纤维血管假体中可实现快速且完全的内皮化。然而，当该方法应用于小口径移植物时，显著的血栓形成倾向一直是个主要问题。通过用带负电荷的肝素掩盖组织碎片中带正电荷的胶原纤维，我们得以克服这一问题。切除犬颈静脉，切成组织碎片并悬浮。通过加压注射，将该混合物通过水孔隙率值为每分钟4000毫升/平方厘米的高度多孔血管假体壁进行筛分，这使得组织碎片被困在移植物壁中。将组织碎片移植物（内径7毫米，长5.7厘米）植入35只犬的胸主动脉。此外，将小口径（内径4毫米，长3.5厘米）的组织碎片移植物用肝素预处理后植入16只犬（32个移植物）的颈动脉。将未进行组织破碎的预凝血移植物作为对照植入胸主动脉（25只犬）和颈动脉（6只犬，12个移植物）。在植入后1至495天取出移植物。在2周内，整个组织碎片移植物中均完成了新动脉壁的形成；然而，在对照移植物中，即使在2个月后，内膜形成也仅限于吻合部位。20个在颈动脉位置用肝素预处理的小口径组织碎片移植物保持通畅，但所有对照移植物在1周内均发生闭塞。这些结果表明，在合成纤维假体中可增强内膜形成；此外，采用这种组织破碎技术，犬的小口径血管移植物有可能实现长期通畅。
