Venous insufficiency occurs when the veins in the legs do not return blood to the heart and upper body normally. Causes include long-term high blood pressure inside leg veins and blood clots in leg veins (deep vein thrombosis or phlebitis).
The veins in the body have valves that prevent blood from flowing the wrong way. These valves keep blood flowing toward the heart. Venous insufficiency means that the valves in the veins have become damaged, allowing blood to flow backward and pool in the leg veins. This results in swelling of the legs (lower extremities) and may cause varicose veins.
Self-care measures may relieve symptoms. These measures include exercising regularly, wearing compression stockings, avoiding long periods of standing, and elevating the legs.
WebMD Medical Reference from Healthwise