WASHINGTON, DC - JANUARY 20: U.S. President Donald Trump delivers his inaugural address on the West Front of the U.S. Capitol on January 20, 2017 in Washington, DC. In today's inauguration ceremony Donald J. Trump becomes the 45th president of the United States.
One-Way Valves in the Veins. One-way valves consist of two flaps (cusps or leaflets) with edges that meet. These valves help veins return blood to the heart. As blood moves toward the heart, it pushes the cusps open like a pair of one-way swinging doors (shown on the left).
If you have CVI, valves in your veins (usually in the leg or sometimes the arms) don't work, causing blood to pool in your legs and putting increased pressure on the walls of the veins. May be due to valve dysfunction (usually hereditary) or due to valve destruction after a deep vein thrombosis (DVT) or blood clot.