Morphological, immunohistological and fibrinolytic features of patch grafts for reconstruction of the inferior vena cava.

Morphological and immunohistological features and fibrinolytic activity of the neointima of various grafts implanted in the thoracic inferior vena cava (IVC) in dogs were examined. Autologous pericardium (group 1), treated porcine pericardium (group 2), treated bovine pericardium (group 3), treated horse pericardium (group 4) and expanded polytetrafluorethylene (e-PTFE) (group 5) were used as patch grafts. Grafts harvested 12-30 (mean 15.2) months after implantation were all patent in each group. The luminal surface of the grafts was completely covered with endothelial cells, which were positive for immunohistological staining of factor VIII and had active fibrinolytic activity. The gross appearance of the neointima of the grafts in group 1 was smooth; however, the grafts in groups 2-5 were severely deformed with retraction. The concavity of the retracted grafts in groups 2-5 was filled with thick neointima, which consisted of a superficial layer with mature smooth muscle cells and the deeper layer with fibroblast-like cells and extracellular collagen fibres. Fibroblast-like cells were thought to be a synthetic form of fibroblasts. The deeper layer of the neointima of the implanted biografts and e-PTFE graft was considered to be in the active phase in cell proliferation, even at > or = 12 months after implantation. It is concluded that autologous pericardium is the material of choice for patch grafts in reconstruction of the IVC and that biografts and synthetic grafts are less than satisfactory.