Chronic Venous Insufficiency (CVI) occurs when the leg veins do not allow blood to travel back to the heart. (Arteries carry blood away from the heart, while veins carry blood to the heart). Problems with valves in the veins can cause the blood to flow both directions, not just toward the heart. Valves that are not working properly can cause blood to pool in the legs.
If chronic venous insufficiency is left untreated, pain, swelling, and leg ulcers may result. CVI is a progressive medical condition that worsens over time and varicose veins can progress to CVI if left untreated.