Venous insufficiency may be the result of blockage (obstruction), valve leakage, or both. The most common mechanism is valve incompetence. Major contributory factors include:
- Prior phlebitis
- Advancing age
- Prolonged standing
- Heavy lifting
The vein valves in the legs can be overstretched or distorted by obstruction upstream, damaged by inflammation, or tortuosity of the vein wall. Weakness of the vein wall is commonly inherited and to some extent may be part of normal aging. Regardless of the cause, damaged or deformed valves do not close completely and allow backward flow of blood (venous reflux). A sustained increase in vein pressure produces chronic inflammation, impaired tissue perfusion, ankle swelling and often debilitating symptoms.