Electrical Potential Differences Across the Normal Aorta and Aortic Grafts of Dogs

Abstract

In the course of an evaluation of freeze dried and fresh aortic homografts in dogs acute and long term studies were made of the potential differences (P. D.) of normal aortic walls and of aortas receiving the 2 types of grafts. In addition the P. D. of the grafts were measured. A Leeds and Northrup potentiometer accurate to 0.2 mv. and special calomel half cells were used to measure the P. D. between saline-filled polyethelene catheters placed across the aorta and/or the graft wall. The normal aortic P. D. was found to be in the range of 0.5-5.0 mv. with the intima negative to the adventitia. Injured or transected artery displayed a reversal of potential. Freeze-dried grafts which displayed no intrinsic P. D. did not thrombose, and displayed relatively little electrical reaction with the recipient aorta. The fresh grafts displayed a reversal of potential (injury P. D.) with the intima positive and reacted more with the recipient aorta. Both types of grafts displayed max. response with their surrounding tissues. The fresh arterial graft usually displayed an injury P. D. after implantation. If this injury P. D. persisted for longer periods the graft invariably thrombosed. In addition the day-to-day P. D. variations in the long term studies were correlated with graft replacement and healing around the graft.