End-to-side venous anastomoses… a patency test

A hitherto unpublished means of testing the patency across an end-to-side venous anastomosis is described. It relies on the elasticity of the venous walls to produce ballooning when the appropriate segments of the veins are occluded and blood is flowing unimpeded across the end-to-side anastomosis. It is foolproof, easy to perform and has no ambiguity in its interpretation.