Experimental evaluation of the length of microvenous grafts under normal tension.

Four groups of microvenous grafts of 2, 4, 6, and 10 cm were used to determine whether length under normal tension affects patency rates in bridging arterial defects. Tension was evaluated by allowing the grafts to assume their normal orientation and length by filling them with blood, under physiological pressure, after the completion of the proximal anastomosis. The length was estimated through the normal range of motion such that the graft would not be too loose and/or tortuous following final anastomosis. The patency rates in the four length groups of this study ranged between 80% and 83%, with no statistical difference between groups. No statistically significant correlation was found between graft length and patency rate. It was concluded that the length of venous autografts does not affect patency.