[Electron microscopic research on the venous valves of the lower extremities in varicose veins].

Electron microscopy of the venous valves in varicose disease shows that dystrophic changes develop on the external and internal surfaces of the valve cusps. Endotheliocytes on the external surface are located longitudinally in relation to valvular axis and on the internal surface they are perpendicular to it. Fragments of the elastic membrane, collagen fibres and smooth muscle cells are seen under the endothelial lining. Endothelium actively regulates proliferative processes of smooth cells secreting the so-called "growth factor of endothelial origin". The development of venous valve pathological changes in varicose disease is accompanied by endothelial damage, disturbance of morphofunctional state of smooth muscle cells and intercellular substance of the vascular wall.