Chronic Venous Insufficiency
This text belongs to a more general article about venous diseases of the lower extremities, which can be found here.
Chronic venous insufficiency is a term used for situation where the leg veins are unable to properly fulfill their function, i.e. to divert blood from the lower extremities.
To understand venous insufficiency, it is necessary to mention the anatomy of the venous system of the lower extremities. The venous blood is drained by two venous systems – the superficial and deep veins. The deep system is able to transport larger amount of blood and it is connected to the surface system with connecting veins. The veins of the lower limbs are equipped with one-way flaps that allow the blood to flow in only one direction (out o the limbs). The connecting veins have also valves that allow one-way blood flow from the superficial venous system to the deep veins and not in the opposite direction. In addition to the valves, the proper blood flow is ensured by the local muscle pump. Contractions of local muscles compress the veins and push the blood in the right direction.
Chronic venous insufficiency means that the above-mentioned system stopped working properly. The majority of cases are related to decreased strength of venous walls and impaired function of the valves. The consequence is blood stasis in the leg veins and emergence of further complications. The chronic venous insufficiency occurs gradually during life. Increased risk is in female sex as women tend to have impaired function of venous valves and decreased strength of venous walls. Other risk factors include obesity, hormonal factors (pregnancy) and jobs with long sitting and standing. Restricted movement impairs the function of local muscle pump and worsens the blood outflow. Chronic venous insufficiency may more easily occur in veins that have been previously affected by deep vein thrombosis.
Venous insufficiency is initially not visibly expressed. The affected person may feel subjective symptoms such as feeling of heavy legs, leg pain and local muscle cramps. Blood stasis may overload the superficial venous system, which may dilate and form visible venous varices. Similar condition occurs when the valves connecting the superficial and deep venous system do not work properly and allow the blood flow from the deep system into superficial.
As chronic venous insufficiency gradually deteriorates, the legs begin to swell and the color of shanks changes by deposition of dark pigment. The viability of the tissues is decreased and so is their healing ability. When the affected leg is injured, the wounds do not heal properly and there is a risk of leg ulcers.
The condition may be prevented by weight reduction, physical exercise and avoidance of long standing or sitting. When sitting, it is advisable to have the lower extremities in elevated position to support the local blood flow. Effective form of prevention is wearing elastic stockings.
In addition to the mentioned preventive measures, there are drugs that improve venous strength and elasticity. These medications are known as venotonics and they can be prescribed as a support therapy. Treatment of complications can be found in related texts.