Combined effect of chronic partial occlusion and orthostatic load on the saphenous vein network: A varicosity model in the rat.

Abstract

We tested the combined effects of chronic flow obstacle and gravitation on the saphenous vein network of rats. A narrowing clip (500 µm, partial occlusion) was administered on the saphenous vein main branch for 4, 8 and 12 weeks, either separately or in combination with chronic orthostatic load (tilted tube-cages for four weeks). Resulting network changes were studied on plastic casts, by video-microscopy, histochemistry-immunohistochemistry and image analysis. A rich collateral venous network developed containing newly formed masses of retrograde conducting small veins. Their walls had less dense elastica, less contractile protein, increased cell division activity and macrophage invasion, and were more sensitive to chronic gravitational load. Hemodynamic disturbance induces remodeling of the saphenous vein network. Walls of veins being in the process of flow-induced morphological remodeling are weak and more sensitive to gravitational load. Reticular vein conglomerates, veins with local dilations, and convoluted courses were observed.