The effect of the "patency test" on arterial endothelial surface

The effect of the "milking patency test" on the arterial endothelium of the experimental rat is investigated. Each of 18 rats served as its own control. Bilateral femoral artery anastomoses were performed in identical fashion. The milking patency test was performed on one side (experimental) but not on the other (control). After removal of the approximator clamps, rats were perfusion-fixed in situ. Harvested experimental vessels stained with silver showed a twofold increase in endothelial cell loss compared to controls. Visual evidence of extensive endothelial loss was seen on silver-stained segments in the tested area. This was corroborated by scanning electron microscopy. The degree of damage seen in this study suggests that the milking patency test is too traumatic for use in clinical microsurgery.