An estimated 30-40% of the U.S. adult population is afflicted with some type of vein problem, and most often these conditions impact the legs. In a normal vein, valves work to move blood back to the heart. When valves malfunction, blood pools in the veins. This condition is known as venous insufficiency. While venous insufficiency is not considered a serious health problem, it can cause varicose veins, leg pain and swelling, skin discoloration and ulcerations for both women and men.