The function of the leg veins is to return blood from the feet to the pelvis. This occurs through the pumping action of the muscles and properly functioning valves. Ninety percent of blood return from the feet to the pelvis normally occurs through the deep veins (inside the muscles). As long as the deep set of veins are working properly, the effect of closing a leaky superficial vein is actually beneficial. The leg circulation will be better off with the leaky vein closed rather than left open and leaking.