Varicose Veins

What Are Varicose Veins?

Contributors to this article:

Harold Ellis  MD CBE DM MCh FRCS
Guy Slowik FRCS

Varicose veins are veins that have become wider and twisted due to a defect in the valves in the vein. These valves normally prevent the backflow of blood in the vein. Since the valves that prevent the backflow of blood in a section of the vein are not working normally, blood pools along  the vein, causing the vein to bulge and swell.

Veins are thin-walled blood vessels that carry deoxygenated blood from the body tissues back to the heart. Varicose veins occur when some of the valves between the deep and superficial veins of the leg no longer function properly.

There are two principal systems of veins in the body:

  1. Deep veins, which lie among the muscles and carry about 90 percent of the blood.
  2. Surface -or superficial- veins, which are often visible just under the skin. Surface veins do not have the protective muscular surrounding of deep veins. This means they are weaker and more likely to become varicose.

Surface veins carry blood from the skin and surface areas into the deep veins via connecting channels called perforator veins.

Here is how blood is moved from the legs toward the heart:

  • The leg muscles squeeze the deep veins, forcing the blood upward.
  • The veins are equipped with “one-way” valves to keep the blood from flowing backwards.
  • As the blood is forced upward, the valves open to allow the blood to pass.
  • After each heartbeat, the valves close momentarily to prevent back-flow.

When a valve between these two systems fails, blood can flow the wrong way because the pressure in the deep veins is greater than in the superficial veins.

  • Instead of taking the blood from the surface veins, the deep veins may actually be pumping blood back into the surface veins.
  • This increases the pressure within the surface veins.
  • As blood pools in the surface veins and the pressure within these veins increases, more and more valves begin to deteriorate.
  • Over a period of time, perhaps years, one valve after another fails.
  • Where this happens, the surface veins swell from the excess blood and high pressure, creating varicose veins.

Although varicose veins usually occur in the legs and feet, they can occur on any part of the body. These include veins in the lower end of the esophagus, the lining of the stomach, the colon, the rectum, and the scrotum.

Varicose veins may result in some discomfort. Usually they cause no symptoms, but in some cases they result in serious medical problems. For many people, varicose veins only cause a problem in terms of appearance-the veins can look ropy and twisted, and may bulge out beneath the skin.

Nice To Know:

Q. Does walking make varicose veins worse?

A. No. Indeed, walking is beneficial. When you walk, the muscles in your legs contract, squeezing the veins, thus helping to force the blood to move forward on its way back to the heart. If walking causes discomfort, you should see your physician to determine why (for example, to exclude any other causes besides varicose veins). Walking is also an excellent form of exercise to help promote good cardiovascular health.


Nice To Know:

Spider Veins

Spider veins are shaped like spider legs and appear in clusters of fine red lines. They commonly occur on the feet, ankles, or thighs, and sometimes the face. This condition goes by several other names, including spider veins, burst veins, venous starts, and telangiectases.

Some health experts consider spider veins a type of varicose veins; others say that they are not varicose veins since they are not subject to any of the complications associated with varicose veins. They are principally a cosmetic problem, although occasionally they may cause symptoms.

Facts About Varicose Veins

  • About 20 percent of all adults develop varicose veins.
  • Most people develop varicose veins between the ages of 30 and 60.
  • Women are four times more likely to develop varicose veins than men.
  • There is a family history of varicose veins in at least 15 percent of all cases.
  • Varicose veins most often occur in the lower legs.

Why Do Varicose Veins Occur?

Varicose veins causes are myriad. Although experts do not know exactly what causes varicose veins, most agree that varicose veins occur because of problems with the valves in the veins.

Valves consist of two thin flaps of tissue (hence they are called bicuspid valves) that open in one direction to allow deoxygenated blood to flow back to the heart. In normal, healthy valves, the two flaps of tissue close tightly, preventing blood from flowing backwards. If valves are damaged, they may not be able to close completely, and blood may leak downward and collect in the vein (called venous insufficiency).

Valves may fail for several reasons:

  • There may be an inadequate number of valves, or the valve may be defective.
  • The vein walls may be weak. Veins with weak walls bulge and damage the valves by pulling the delicate leaves of the valves apart.
  • Valves may be damaged by blood clots. Although the clot dissolves, valves may become scarred. These damaged valves then fail to operate properly.
  • In some cases, the vein itself may be at fault. Obesity, pregnancy, or periods of prolonged standing may put excessive pressure on a leg vein, causing the walls of the vein to bulge. When this happens, the two halves of the valve are forced too far apart, and they cannot completely block blood from flowing backwards during the closing phase. Thus, some blood is allowed to flow downward.
  • Anything that causes strain for a lengthy time may lead to increased pressure on leg veins and weakened valves. Conditions that may cause problems with valves include chronic cough or constipation and urinary retention due to an enlarged prostate.
  • Aging may coincide with valve problems. Almost all people older than 65 have some varicosities.

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