Canine Venous Graft Transplated into the Arterial System: Factors Related to Lipid Deposition and Patency

Abstract

For clarifying the influences of nutritional changes in the venous graft on lipid deposition and patency, 12 dogs were bilaterally grafted with the autogen ous femoral veins into the femoral arteries, and the venous grafts on the left side were then wrapped with a Tetron sheet to impede the reconstruction of vasa vasorum. After feeding 4% cholesterol and 2% coconut oil to the dogs for 7 to 15 weeks, the serum cholesterol increased significantly (P<0.01) from 131.2 ± 12.8 to 222.9 ± 33.1 mg/dl, though it still remained relatively low. No statistical difference in patency was recognized between the two sides. In the left patent grafts, vascular lesions were not uniformly seen. Dilatation of the graft without intimal thickening was seen in 3 dogs, while marked intimal thickening without dilatation was noted in 5. Wide lipid deposition was ob served in 8 of 10 grafts on the right side showing a statistical difference (P<0.01). The distribution of vasa vasorum in the left grafts varied widely on microangiography. Intimal thickening and deposition of lipids were observed correlatively in the area with a poor distribution of vasa vasorum. From the above results, the disturbance of vasa vasorum may be an important underly ing condition in lipid deposition in the vascular wall. For preventing occlusion, it was recommended to exercise care so as to avoid stripping the adventitial layers in the venous graft and to place the graft through well vascularised tissues, and also to control the serum cholesterol before and during the first 3 months after the operation. Consideration and discussion of the causes of the confusing results relating lipid deposition and intimal thickening in the grafts have been done from a view of disturbance of vasa vasorum.