Scanning electron microscopic evaluation of variably angled end-to-side microvascular anastomoses.

A comparison of right-angled and opposing oblique-angled end-to-side microvascular anastomoses with both patent and occluded recipient vessels was performed in rats. Patency rates after 3 weeks were comparable in all types of anastomoses (average, 92%). However, scanning electron microscopic evaluation revealed a variety of both nonspecific (pits, craters, folds, etc.) and angle-dependent (mounds, erosions, bridges, etc.) endothelial alterations. It is concluded that, in proximally patent recipient vessels, the functional integrity of the anastomosis is not related to the grafting angle; however, in proximally occluded recipient vessels, retrograde-directed oblique angles may lead to progressive embarrassment of anastomotic function.