Weak or weakened valves may lead to varicose veins. Arteries have blood from the guts to the remainder of the system. Veins return blood from the rest of the body to the center. To return blood to the center, the veins within the legs will have to work versus gravity. https://www.sgvascularctr.com/varicose-vein-treatment-in-singapore-from-the-perspective-of-a-vascular-surgeon/