Venous Insufficiency

Chronic venous insufficiency is a failure of the lower-extremity venous system to return blood effectively during upright activity. The central problem is sustained ambulatory venous hypertension: pressure in the leg veins remains abnormally high while the person is standing or walking. Normally, the calf muscles contract during walking and squeeze the deep veins. One-way valves direct blood upward and prevent backward flow when the muscles relax. Incompetent valves allow reflux, an obstructed deep venous pathway limits outflow, and an ineffective calf-muscle pump fails to generate adequate forward flow. Any one of these problems—or several together—can maintain excessive venous pressure. The elevated pressure is transmitted to small vessels in the skin. Fluid and proteins move into the surrounding tissue, producing dependent edema. Ongoing endothelial stress recruits leukocytes and sustains inflammation. Over time, hemosiderin deposition causes brown pigmentation, the dermis becomes fibrotic, and the skin loses its ability to tolerate minor trauma or repair a wound. This is why a small injury near the ankle can become a chronic ulcer. Primary disease usually reflects superficial venous reflux or valve dysfunction. Secondary, or...