Neovascularization of pseudointima as found in the freeze-dried homologous vein graft for the peripheral arteries

• Published in: Blood & Vessel Vol. 7; no. 5; pp. 385 - 391
• Main Authors: MORIYAMA, Masaaki, KUSABA, Akira, KIYOSE, Takashi, FURUYAMA, Masato, OKADOME, Kenichiro, INOKUCHI, Kiyoshi
• Format: Journal Article
• Language: English
• Published: The Japanese Society on Thrombosis and Hemostasis 1976
• Subjects: canine femoral reconstruction; homologous vein patch graft; microfil infusion; microscopic examination; newly developed vascular channel; nutrition of pseudointima; serial section technique
• ISSN: 0386-9717; 1884-2372
• DOI: 10.2491/jjsth1970.7.385

In our previous studies on the freeze-dried homologous vein graft implanted to the canine femoral artery as a patch graft, complete patency (22/22) and satisfactory healing of the pseudointima were observed. In these studies, a fine vascular channel communicating directly with the arterial lumen and being lined with the endothelial-like cells was found in the pseudointima microscopically. It was considered that this vascular channel in the pseudointima must be a newly developed vessel to nourish the fibrously thickened pseudointima of the graft. In this study, the microscopic examination by serial section technique and transluminal Microfil infusion method were carried out in order to make distinct the process of development and extension of these vascular channels in the thickened pseudointima. The freezedried homologous vein grafts were implanted to the canine femoral arteries as a patch graft and ten grafts were examined at various intervals from 3 to 175 days after implantation. In early stage, that is 10 and 11 days after implantation, some clefts communicating directly with the arterial lumen and containing some red blood cells were found in the mural thrombi near the suture line. They seemed to be an earliest feature of the above mentioned vascular channel. In all specimens 21 days and more later after implantation vascular channels communicating directly with the arterial lumen were found in the fibrously thickened pseudointima near the suture line as well as the central portion of the grafts, these vascular channels were more often observed near the suture line than the central part of the graft. They were lined with endothelial-like cells completely. The vascular channels arose from the arterial lumen near the suture line extended into the deeper layers of the pseudointima branching off in tributaries and some reached to the adventitial layers penetrating through the fibrous tissues proliferated in the suture line. On the other hand, those from the arterial lumen near the central part of the graft were found to develop vertically into the pseudointima and the extension was confined within the pseudointima without penetrating the graft towards the adventitial layer. Same findings as mentioned above were observed in microscopic examination by transluminal infusion of Microfil. From the findings above mentioned, it seemed reasonable to presume that the vascular channels communicating directly with the arterial lumen were not extension of the vasa vasorum from the adventitial layers but newly developed vessels in order to nourish the pseudointima of the graft, and they were formed through the clefts which was formed in the mural thrombi in the course of their organization in early stage.