 Venous insufficiency results when the normal functioning of the valves , which serve to keep blood flowing to the heart and to prevent reflux , become damaged and incompetent . This incompetence will result in an insufficient <unk> through the affected vein or veins . In varicose veins the valves are damaged or missing and the insufficiency will be chronic . When the valves are damaged blood leaks and pools in the legs and feet . 
