01/04/2026
The veins in your legs carry blood back up to your heart. They have one-way valves that keep blood from flowing back downward. When you have chronic venous insufficiency (CVI), these valves can't close completely. As a result, some of the blood goes back down into your legs and pools in the veins there. CVI can also keep your leg muscles from pumping enough blood back toward your heart. It sometimes results in vein blockages, too.