Chronic Venous Disease

Chronic Venous Disease (CVD) is the country’s most prevalent chronic disease impacting an estimated 175 million adults in the U.S.¹ CVD is used as a broad term to define the spectrum of manifestations of venous disease. Chronic Venous Insufficiency (CVI) is a large subset of CVD which occurs as a result of increased venous pressure (venous hypertension) within the veins of the leg, most often caused by the failure of valves within the veins of the leg to properly open and close (valvular incompetence).

Blood Flow From the Legs Back to the Heart

Once blood has been circulated throughout the lower body, the calf muscle serves as a pump to squeeze blood up the veins of the leg, against gravity, and through a series of one-way valves. In a healthy person, the venous system acts in a similar manner to locks and dams along a river. When blood propelled by the calf muscle reaches a valve, the valve opens, the blood passes through, the valve is supposed to close, and the blood moves on to the next valve much like a climber who ascends the rungs of a ladder. When valves in the veins of the legs fail and become incompetent, they begin to leak and, if destroyed, they do not close at all. The same thing happens with blood in the veins of the leg when valves fail. The calf muscle pushes the blood up the veins, but if the valves don’t hold, gravity takes over and blood flows back in the wrong direction (reflux) and pools in the lower leg and ankle area. With nowhere to go, the pooling blood causes increased pressure inside of the veins of the leg (venous hypertension).

1. McLafferty RB, Passman MA, Caprini JA, Rooke TW, Markwell SA, Lohr JM, et al. Increasing awareness about venous disease: The American Venous Forum expands the National Venous Screening Program. J Vasc Surg 2008;48:394-9.