Microvenous grafts to arterial defects. The use of mechanical or suture anastomoses

A mechanical microvascular anastomotic device, the Unilink system, was compared with sutures in terms of patency, anastomotic time, and histologic changes when a microvenous graft is placed in an arterial defect. Twenty rabbits underwent grafting of a 1.0-cm defect in both carotid arteries with a 1.5-cm reversed femoral vein graft. Anastomoses were performed with the Unilink system on one side and sutures on the other. Animals were killed at 2 weeks (10 animals) and 16 weeks (10 animals) with the vein grafts being assessed with clinical patency tests and then fixated for histologic evaluation. All 20 grafts (100%) interposed with the Unilink system were fully patent while 17 (85%) of the 20 grafts interposed with sutures were fully patent. The grafting procedure with the Unilink anastomoses averaged 12.5 minutes while the sutured anastomoses averaged 41.9 minutes. No differences in the histologic appearance of the vein grafts were noted between the two types of anastomoses. All grafts showed endothelialization at 2 weeks with intimal hyperplasia or "arterialization" being a constant finding.