Morphological alterations of non-varicose and varicose veins. (A morphological contribution to the discussion on pathogenesis of varicose veins).

Venous valves do not play a role in pathogenesis of primary varicose veins. Their number remains constant during life time. In varicose veins their insufficiency is secondary. Intimal fibrosis is no prerequisite for the development of varicose veins. It is a frequent finding in non-varicose veins of all age groups. Fibrosis of media and adventitia is no early morphological alteration in varicose veins. Fibrotic replacement of smooth muscles represents a late stage of varicosis. Degenerative lesions of deep leg veins are rare even at old age. The deep veins are not influenced by sclerotic lesions of the adjacent arteries. Preexisting intimal fibrosis in autogenous graft veins may be one of several factors which induce an overshooting intimal proliferation. Degenerative alterations (fibrotic lesions of the wall layers, insufficiency of the valves) are secondary phenomena in pathogenesis of varicose veins which follow a functional deficiency of the smooth musculature.