ABC of vascular diseases. Deep venous insufficiency and occlusion.

Abstract

Sequence of events leading to venous ulc?ration Pulmonary embolus is a serious complication of deep vein thrombosis but deep venous insufficiency or occlusion, or both, are much more common long term problems and many venous ulcers occur each year, putting strains on both the work force and health service resources. It has long been recognised that deep vein thrombosis is usually followed by recanalisation of the veins and that this process results in destruction of the venous valves, which in turn results in deep venous insufficiency. Failure to recanalise results in chronic venous occlusion with the development of a collateral circulation that is also without valves. Either event has a deleterious effect on the function of the calf muscle pump, resulting in high venous pressure in the leg and foot even during exercise. This is the fundamental abnormality that results in a postphlebitic limb with venous ulc?ration or venous claudication. In addition, some patients have a congenital absence of competent valves without evidence of previous thrombosis.