Microvascular repair with 1-mm polytetrafluoroethylene (PTFE) grafts: effect of recombinant tissue-type plasminogen activator (rt-PA) on the patency rate and healing process

The present study assesses the effect of recombinant tissue-type plasminogen activator (rt-PA) on the patency rate and healing process of microvascular polytetrafluoroethylene (PTFE) grafts. Wistar rats were used, divided into four groups of 25 animals each. After dissection of the carotid artery a segment of the vessel, 1 cm long, was resected and replaced by equal length graft. Two different type fibril length (30- or 60-microm) grafts of the same wall thickness (0.18 mm) were used. Normal saline or 3 mg/kg of body weight of rt-PA was applied locally in each group of different fibril length grafts. Patency tests were performed at 15 min and 4 weeks after blood flow was reestablished. All grafts were harvested and examined histologically. The results showed that local application of rt-PA improves patency statistically significantly in both types of fibril length grafts. Patency in 60-microm fibril length grafts was statistically significantly higher than that of 30-microm fibril length grafts, whether rt-PA was used or not. The use of rt-PA had no influence on the healing process of either type of graft.