Information About Veins

This site has been created to address certain clinical, educational, and research aspects of venous disease. This section defines a few of the conditions associated with venous disease and outlines basic methods of prevention and treatment.

DEFINITIONS:

Thromboembolism:
This is a term used to describe a deep vein thrombosis or pulmonary embolus. The deep vein thrombosis may occur in a leg, an arm, or other locations in the body.

Deep Vein Thrombosis: (DVT)
DVT is a condition involving a blood clot, usually in the legs, but can also occur in the pelvic, arm, or neck veins. The term "deep" is used because most of the major veins are located deep in the fascial layers of the body. When a clot forms in these veins, it can break off and go through the heart and into the lungs to produce pulmonary emboli.

Superficial Vein Thrombosis: (SVT)
Refers to a venous blood clot occurring in a surface vein of the arm or leg, or in any part of the body where the vein is in the superficial tissues.

Pulmonary Embolus:
May be defined as a blood clot that began in the pelvis or legs, migrated into the vena cava, back through the heart and out through the pulmonary artery to the lungs where it became lodged.

Varicose Veins:
These are surface veins which are dilated and visible from the surface. They usually have weakened walls and bulging points, hence the term varicose.

Chronic Venous Insufficiency:
Refers to a constellation of symptoms in legs, including swelling, skin discoloration, ulceration, varicose veins, pigmentation of the skin, as well as other symptoms such as aching, tenderness and heaviness that result from the blood not being properly pumped back to the heart. Normally, blood is pumped out of the leg veins that are located within the large muscles of the leg. When these muscles contract, the blood moves up toward the heart. The deep venous system connects to the surface venous system in over 150 locations in each leg. At each location there is a one-way valve that closes when the pressure in the deep veins rises during muscular contractions. If this valve fails to close, then instead of the blood being propelled through deep veins up toward the heart, it can leak out to the surface veins causing them to expand or dilate. If enough blood leaks to the surface, congestion can occur and the back pressure of excessive blood in the venous system can inhibit the flow of arterial blood into the vital capillaries (tiny blood vessels) where oxygen and other nutrients are exchanged. The good elements being brought into the leg and the bad elements carried out of the leg are exchanged at this very critical capillary interface between the arteries and veins. Increased back pressure on the venous side inhibits flow into the capillaries and results in changes in the capillaries whereby the normal flow of nutrients cannot occur. This damage at the capillary level can lead to the chronic changes that were previously listed, including swelling, rashes, ulceration, etc.

Post-thrombotic Syndrome:
This is a constellation of symptoms that occurs after a deep venous blood clot in the leg. These symptoms are the same as described for chronic venous insufficiency, and this complex of symptoms may take months or years to develop after the original blood clot occurred. Approximately 25% of people who have a blood clot in the leg (deep vein thrombosis as it is commonly referred to) will eventually develop post-phlebitic syndrome. Seven percent of these patients will have a severe form that will inhibit or limit their activities, ability to work and function.

ETIOLOGY:

Prevention: (Thrombosis Prophylaxis)
This is a term which means to prevent venous blood clots. It usually refers to the prevention of blood clots in the legs, which is the most common location. These preventive measures are necessary if a person is immobilized at bed rest for more than three days with an illness, undergoes a surgical operation or sustains trauma from an accident, and is immobilized. Sometimes these latter conditions are also associated with leg fractures.

Treatment: (Therapy for Thromboembolism)
Therapy for venous blood clots and/or pulmonary emboli is usually in the form of heparin. Today, most patients are treated with one of several low molecular weight heparins (LMWH), although unfractionated heparin is popular in some practices. Other drugs that are used for treatment include: warfarin, which is given for long periods of time by mouth, and clot dissolving drugs, which work by breaking up the blood clots.