Chronic venous insufficiency (CVI) or Venous Reflux Disease is very common, and it affects about 20 percent of the population – nearly 24 million Americans. CVI occurs when the leg veins can’t pump enough blood back to the heart.
When you are standing in an upright position, the blood in the leg veins must push against gravity to pump the blood back to the heart. When you are active or walking, the muscles in your legs squeeze the deep veins oft the legs to help push blood back up to the heart. Valves in the veins act as one-way flaps opening and and closing to keep the blood flowing in the right direction and preventing blood from flowing in reverse, back down the legs. The whole process of sending blood back to the heart is called the venous pump.
The venous pump works well when walking and the muscles are squeezing the deep veins, but when sitting or standing, especially for a long time, the blood in the leg veins can pool and increase the blood pressure in the veins. Deep veins and perforating veins can usually handle short periods of increased pressures. However, sitting or standing for a long time can stretch out vein walls from this increased pressure. Over time, in susceptible individuals, this can weaken the walls of the veins and damage the vein valves, causing CVI.
Risk factors for chronic venous insufficiency include obesity, prolonged standing, pregnancy, trauma, weak muscles in the leg, heredity, and smoking. Dilated veins and improper valve function result in an increase in venous blood pressure. This, in turn can result in swelling, skin color changes (hyperpigmentation), hardening of the skin, varicose veins, and even ulcers.
If you have CVI, your ankles may swell and your calves may feel tight. Your legs may also feel heavy, tired, restless, or achy. You may feel pain while walking or shortly after stopping.
CVI may be associated with varicose veins. Varicose veins are swollen veins that you can see through the skin. They often look blue, bulging, and twisted. Large varicose veins can lead to skin changes like rashes, redness, and sores.
CVI can also cause problems with leg swelling because of the pressure of the blood pooling in the veins. Your lymphatic system may also produce fluid, called lymph, to compensate for CVI. Your leg tissues may then absorb some of this fluid, which can increase the tendency for your legs to swell. In severe cases, CVI and the leg swelling can cause ulcers to form on the lower parts of the leg.
CVI can be detected using Duplex ultrasound. The duplex ultrasound uses painless sound waves higher than human hearing can detect, and allows a health care provider to measure the speed of blood flow and to see the structure of the leg veins.