Effects of blood flow and venous network on the survival of the arterialized venous flap.

The purpose of this study was to evaluate further factors that could explain the survival mechanism in the arterialized venous flap. The authors used 16 canines to investigate the survival rate and pattern of the arterialized venous flap and compared the results with those of the conventional saphenous flap. The number and distribution of draining veins in the arterialized venous flap group were varied to observe their impact on the survival rate and pattern. Gross examination of venous network, blood gas, venogram, blood pressure, and histologic study were also carried out. Although there was no significant difference in final survival rate between conventional flap and arterialized venous flap with two efferent veins (p > 0.01), that of the arterialized venous flap increased significantly as the number of draining veins increased. Blood gas analysis showed that more effective oxygen consumption took place when the number of draining veins increased. By measuring the blood flow and volume at 8 hours after the operation with a laser Doppler flowmeter, it was possible to predict the necrosis of the arterialized venous flap. Attachment to a high pressure arterial blood flow system induced smooth muscle proliferation and neogrowth of elastic fibers in the veins. Furthermore, progressive narrowing of the lumen hastened the development of a collateral circulation, demonstrated on a venogram by the tortuous vessels and neovascularization up to the flap margin. To make it possible to predict and achieve complete survival of the arterialized venous flap, the following criteria must be considered: (a) an arterialized venous flap should be designed to contain most of the venous network in the center, (b) the arterial inflow has to be anastomosed to one afferent vein, (c) two or more efferent veins should drain the arterialized venous flap.