Initial histopathology of the autovein graft in late occlusion after arterial reconstruction.

Five patients developed local stenosis of autologous vein grafts implanted for femoro-popliteal arterial occlusive lesions. This stenosis occurred in the vein grafts 2 months to 5 years after the initial operation. Histopathologic study revealed that the stenotic segments had a thickened intima with a prominent proliferation of smooth muscle cells associated with fibrous extracellular matrix. There were no findings showing deposition of mural thrombi, as has heretofore been reported. The intimal thickening due to excessive fibromuscular proliferative response of the vein graft may possibly play an important role in the development of late graft occlusion.