Experimental study of the influence of arterial trauma on dependent distal tissue survival.

An experimental model was developed combining arterial trauma with island flap creation using the rat groin flap system. Flap arteries were subjected to crush/avulsion injuries with subsequent microvascular repair. A second series involved resection 4 hr after thrombosis of injured flap arteries and interpositional vein grafting to reestablish circulation. A single bolus of systemic heparin was administered to half of the animals from each series on a blinded, randomized basis. Arterial patency at 7 days correlated with flap survival. There was no case of partial flap loss. Patencies improved in the first series from 31% to 71% with heparin administration (P less than 0.05) and from 58% to 90% in the second (not significantly different). A third series involving immediate resection of traumatized vessel and vein graft replacement achieved a patency of 92% (without heparinization). These results support the value of replacement of all traumatized arterial tissue with vein grafts and indicate the efficacy of systemic heparin (in single bolus) for enhancing the likelihood of maintaining patency. Furthermore, it is suggested that the occurrence of a thrombogenic site in the arterial inflow to a region of dependent tissue does not lead to partial tissue loss, and thus thromboembolic events may not be responsible for this clinical phenomenon.