Histopathology of veins and venous valves of patients with venous insufficiency syndrome: ultrastructure.

Vein and vein valve biopsies were obtained from venous insufficiency syndrome (VIS) patients undergoing venous valve transplants. Normal control biopsies were obtained from other non-VIS procedures. The specimens were examined using light and transmission electron microscopy (TEM). Biopsies from VIS patients showed a variety of changes from what was considered normal structure. Most histopathologic changes were noted in the endothelium and subendothelial layer of the vein valve and wall, and in the media of the vein wall. These changes included 1) erosion of the endothelium with consequent adherence of blood elements, 2) intact endothelium with a thickened subendothelial zone which was populated with migrated smooth muscle and perhaps other cell types, 3) occurrence of abnormal or over-abundant collagen, and 4) thickening of the media with changes in the smooth muscle population therein.