The Viability of Experimental Aortic Grafts, and its Influence on the Functional Result of Transplantation

Abstract

Since Carrel's fundamental experimental work early in this century the technique of blood vessel transplantation has been used to a continuously increasing extent in the surgical treatment of various traumatic and pathologic conditions. The essential aim in transplantation of a blood vessel segment is to maintain the blood flow, and much experimental work has been carried out to determine the conditions which influence the effectiveness of the transplantation. In particular, the question of whether living blood vessel segments give better functional results than dead ones has attracted great attention, but there is still no final agreement although many investigators have studied this problem.In earlier studies, the methods used to demonstrate the presence of life in the blood vessel transplants usually involved either histologic examination after fixation of the material, determination of the tissue respiration, or tissue culture experiments. In studying the viability of vascular transplants their vascularization has also been studied.The advantage of using grafts with &dquo;latent&dquo; or &dquo;potential&dquo; life was stressed by Carrel (1-3) who, in studying the result of experimental transplantation of homologous segments of arteries, found less degenerative changes in grafts which had been fresh at the transplantation and therefore had been considered to have &dquo;latent life,&dquo; than in those which definitely consisted of dead tissue. Bode and Fabian (4) showed that arterial segments which had been stored for not longer than 35 to 50 days were most suitable for homologous transplantation, but they also showed that blood vessel segments which had been fixed in formalin-and were thus dead-were also capable of maintaining the blood circulation. They stated that for transplantation in man, autogenous material was preferable.In 1949 Gross and co-workers (5, 6) published extensive experimental work on homologous arterial transplantation, which led to increased utilization of this type of material in man. By tissue culture studies they demonstrated living cells in aortic segments which had been preserved in nutrient fluid for up to 38 days, and they pointed out that this type of viability was fundamental for a proper healing and satisfactory function of the grafts. Peirce (7) compared the results of a great number of investigators who had worked with viable and nonviable material and concluded that the viable grafts gave better functional results because of better healing and less formation of thrombi. He suggested that the living cells in the intima of transplanted segments prevented early formation of thrombi and also took an active part in the