The Varicose Saphenous Vein, Functional and Ultrastructural Studies, with Special Reference to Smooth Muscle

Abstract

Specimens from the proximal and distal parts of saphenous vein of 16 patients undergoing stripping operations for varicose veins were investigated with pharmacological technique and electron microscopy. The ultrastructural investigation showed a venous wall with increased connective tissue elements such as collagen fibres. In parts endothelial damage could be observed. These changes were about equally frequent in specimens from the proximal and distal great saphenous vein. The pharmacological study showed reduced maximal contraction of varicose veins compared to controls. Moreover there was a slightly higher maximal tension (contraction per unit trans-sectional area) in specimens from the lower leg, compared to the thigh. This means that there is functional disturbance of the smooth muscle function in varicose veins, and other structural elements show significant alterations such as connective tissue and endothelial cells.

Endothelial mediated enhancement of noradrenaline induced vasoconstriction in normal and varicose veins

“…The present study shows that in varicose veins the contraction facilitating effect of the endothelium is reduced or lost. Therefore, damage to the endothelium as previously shown by structural studies (Villavicencio et al 1986;Thulesius et al, 1988b) and 158 0. Thulesius et al…”

“…Change in varicose veins was not significant. (Thulesius & Gjores, 1974;Thulesius et al, 1988b). This reduction in contractile force was present in rubbed and non-rubbed vessels and seems to be due to a reduced smooth muscle content of the vessel wall.…”

“…In canine saphenous and human umbilical veins this factor is not prominent in response to standardized stimuli (De May & Vanhoutte, 1982;Seidel & LaRochelle, 1987;Van de Voorde et ul., 1987) and we have presented evidence that the human saphenous vein releases an endothelial-derived contracting factor (EDCF) (Thulesius et ul., 1988a). We therefore wanted to test the hypothesis that reduced tone in varicose veins and loss of EDCF may be related to a primary endothelial abnormality since ultrastructural studies have shown endothelial damage in varicose veins (Villavicencio et al, 1986;Thulesius et al, 1988b). The present study was designed to investigate if noradrenaline-induced responses of isolated normal and varicose veins were altered by removal of the endothelium.…”

Venous compliance and clinical implications

“…The volumetric increase (dV) of the content is correlated with pressure increase (dP) inside the vein (the equation is C'= dV/dP). [5][6][7][8][9][10][11][12][13][14][15] The components of the media layer of veins, described above, permit to the venous system to achieve high compliance respect to artery. Within the human body 75% of blood circulates in the venous system, because of greater compliance of veins respect the arteries.…”

“…In Figure 5 it is well apparent the different behavior of the venous pressure when the vein is filled and distended by the blood respect to the empty vein ( Figure 5). [11][12][13] During the filling phase there is a significant increase in diameter of the vein with little change in pressure, [11][12][13] in which the vein wall is not distended by the increase in blood volume. In other words, during this first phase the pressure/volume relationship is not linear ( Figure 5).…”