Wrapping and Replacement of Thoracic Aorta: Morphologic and Mechanical Properties

Abstract

The histologic and mechanical properties of the aorta following its segmental wrapping or replacement was investigated in two groups of dogs. In Group I (5 dogs) a 3- to 4-cm segment of the ascending and of the descending aorta were wrapped with prosthetic graft (2 dogs with woven and 3 with knitted Dacron). In Group II (5 dogs), a 3-cm segment of the de scending aorta was replaced with prosthetic graft. After an average stay of eight months, the dogs were sacrificed and the aorta was submit ted for histologic and tensile strength studies. There was no change in rup ture strength in either the wrapped or the replaced aortas in comparison with normal control aortas. However, the incidence of rupture at the suture line in Group II was significantly greater. The incidence of rupture site in Group I was 43.5% at the normal aortic segment, 17.4% at the junction between wrapped and nonwrapped aortic segment, and 39.1 % at the wrapped aortic segment. The inci dence of rupture site in group II was 28.9% at the normal aortic segment, 68.9% at the suture line, and 2.2% at the grafted segment. In Group I dogs the outer one third to one half of the media of the wrapped aortic segment was replaced with fibrous tissue.