What is chronic venous insufficiency?

Arteries bring oxygen-rich blood from your heart to the rest of your body. Veins return oxygen-poor blood back to your heart. When your leg veins cannot pump enough blood back to your heart, you have chronic venous insufficiency (CVI). CVI is also sometimes called chronic venous disease, or CVD. You have three kinds of veins, superficial veins, which lie close to the skin, and deep veins, which lie in groups of muscles. Deep veins lead to the vena cava, your body's largest vein, which runs directly to your heart. Perforating veins connect the superficial to the deep veins.

The blood in your leg veins must go against gravity to return to your heart. Your leg muscles squeeze the deep veins of your legs and feet to help move blood back to your heart. One-way flaps called valves in your veins keep blood flowing in the right direction. When your leg muscles relax, the valves inside your veins close. This prevents blood from flowing backward. The entire process of sending blood back to the heart is called the venous pump.

When you walk and your leg muscles squeeze, the venous pump works well. But when you sit or stand, especially for a long time, the blood in your leg veins can pool and increase blood pressure. Deep veins and perforating veins are usually able to withstand short periods of increased pressures. But sitting or standing for a long time can stretch vein walls because they are flexible. Over time, in susceptible individuals, this can weaken the walls of the veins and damage the vein valves, causing CVI.

What are the symptoms?

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 more of a 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.

What causes CVI?

Long-term high blood pressure inside your leg veins causes CVI. Other causes of CVI include deep vein thrombosis (DVT) and phlebitis.

DVT occurs when a blood clot (called a thrombus) blocks blood from flowing out of a deep or perforating vein. Blocked veins can increase vein blood pressure, which overloads your valves. Vein valves that do not work properly are called incompetent, and incompetent valves contribute to CVI. DVT is a potentially serious condition that causes leg swelling and requires immediate medical attention because sometimes the blood clots in the veins can break off and travel to the lungs. This condition is called a pulmonary embolus.

Phlebitis occurs when a superficial vein becomes swollen and inflamed. This causes a blood clot to form, which can also cause DVT.

Factors that can increase your risk for CVI include a family history of varicose veins, being overweight, being pregnant, not exercising enough, smoking, and standing or sitting for long periods of time. Your age and sex can also increase your risk of developing CVI; older than 50 most often get CVI.

What tests will I need?

First your physician asks you questions about your current general health, past medical history, and symptoms. In addition, your physician conducts a physical exam. Together these are known as a patient history and exam. Your physician may measure the blood pressure in your legs and will examine the varicose veins. To confirm a diagnosis of CVI, the physician may order a duplex ultrasound test or sometimes another test called a venogram.

Duplex ultrasound uses sound waves higher than human hearing can detect. Duplex ultrasound allows your physician to measure the speed of blood flow and to see the structure of your leg veins.

A venogram is an x-ray that also allows your physician to see the anatomy of your veins. During this test, your physician injects a dye that makes your veins appear on an x-ray.