Chronic venous insufficiency (CVI) occurs when the venous wall and/or valves in the leg veins are not working properly, making it difficult for blood to return to the heart from the legs. CVI causes blood to collect in these veins.
Veins return blood to the heart from all the body’s organs. To reach the heart, the blood needs to flow upward from the veins in the legs. Calf muscles and the muscles in the feet need to contract with each step to squeeze the veins and push the blood upward. To keep the blood flowing up, and not back down, the veins contain one-way valves.
Chronic venous insufficiency occurs when these tiny valves become damaged, allowing the blood to leak backward. Valve damage may occur as the result of aging, extended sitting or standing or the combination of aging and reduced mobility. When the valves are weakened to the point where it is difficult for blood to flow up to the heart, blood pressure in the veins stays elevated for long periods of time, leading to CVI.
CVI most commonly occurs as the result of a blood clot in the deep veins of the legs, a disease known as deep vein thrombosis (DVT). CVI can also result from pelvic tumors and vascular malformations, and sometimes occurs for unknown reasons. Failure of the valves in leg veins to hold blood against gravity leads to sluggish movement of blood out of the veins, resulting in swollen legs.
Chronic venous insufficiency that develops as a result of DVT is also known as post-thrombotic syndrome. As many as 30% of people with DVT will develop this problem within 10 years after diagnosis.
The seriousness of CVI, along with the complexities of treatment, increase as the disease progresses. The earlier it is diagnosed and treated, the better the chances of preventing complications.
If CVI is not treated, the pressure and swelling in the legs may increase until capillaries burst. When this happens, the skin turns a reddish-brown color and is very sensitive if bumped or scratched.
At the least, burst capillaries can cause local tissue inflammation and internal tissue damage. At worst, this leads to open sores on the skin surface. These venous stasis ulcers can be difficult to heal and can become infected. When the infection is not controlled, it can spread to surrounding tissue, a condition known as cellulitis.
To diagnose CVI, a Deborah Heart and Lung Center physician will perform a complete medical history and physical exam. A test called a vascular or duplex ultrasound may be used to examine blood circulation.