heart and blood vessel disorders
Chronic Venous Insufficiency and Post Thrombotic Syndrome
Causes of Chronic Venous Insufficiency
Arteries carry blood with oxygen and nutrients away from the heart to the rest of the body. Veins return blood to the heart from the rest of the body. Blood returns from the legs through shallow and deep veins. Contraction of leg muscles pushes blood through the Deep Veins of the Legs . Valves in the veins keep blood flowing upward toward the heart and stop the blood from flowing backward. Chronic venous insufficiency occurs when something widens the leg veins and/or damages the valves in the veins. These changes decrease blood flow in the veins and increase the pressure in the veins. The increased pressure and low blood flow cause fluid to accumulate in the legs and other symptoms. 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 flaps open like a pair of one-way swinging doors (shown on the left). If gravity or muscle contractions momentarily pull the blood backward or if blood begins to back up in a vein, the flaps are immediately pushed closed, preventing backward flow (shown on the right). Themost common causeof chronic venous insufficiency is Previous blood clot in the legs ( Deep Vein Thrombosis (DVT) ) A blood clot may cause chronic venous insufficiency because scar tissue from the clot may damage the valves in the veins. Some people may then develop post-thrombotic syndrome, which is chronic venous insufficiency with symptoms. Otherrisk factorsfor chronic venous insufficiency include Injury to the legs Aging Obesity None Sitting or standing for long periods Pregnancy Not everyone who has a blood clot in the leg develops post-thrombotic syndrome. People who are at increased risk following a blood clot in the leg include those who have had Several episodes of blood clots in the same leg A blood clot in the upper part of the leg and/or pelvic region People who have obesity also may be at increased risk of post-thrombotic syndrome. 