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Varicose Veins (cont.)

Varicose Vein Causes

Many theories exist for why varicosities occur in veins, but the consensus is that defective/damaged valves within the veins are the cause.

Valves prevent backward flow of blood within the vein. They keep blood in the vein moving toward the heart. It is unclear what causes the valves to work less efficiently.

  • Some experts think inherited problems cause some people to have too few valves or valves that do not function properly.
  • Some people may be born with abnormalities of the vein wall. The resulting weakness may predispose the valves to separate and become leaky.

The result is that when a person with poorly functioning valves stands up, the blood flow actually reverses and flows down the superficial veins, when it should be flowing up, toward the heart.

  • When the muscles surrounding the deep veins contract, emptying the deeper veins, a build-up of pressure occurs.
  • This causes even more blood to flow the wrong way from the deep to the superficial veins through faulty valves in the perforator veins.
  • This increases pressure in the superficial veins and causes varicosities.

Many factors can aggravate the varicose veins.

  • Pregnancy is associated with an increase in blood volume. Also, added pressure on the veins in the legs by the weight of the growing uterus and the relaxation effects of the hormones estrogen and progesterone on the vein walls contribute to the development of varicose veins during pregnancy.
  • Prolonged standing
  • Obesity or distended belly
  • Straining: Chronic constipation, urinary retention from an enlarged prostate, chronic cough, or any other conditions that cause a person to strain for prolonged periods of time causes an increase in the forces transmitted to the leg veins and may result in varicose veins. These mechanisms also contribute to the formation of hemorrhoids, which are varicosities located in the rectal and anal area.
  • Prior surgery or trauma to the leg: These conditions interrupt the normal blood flow channels.
  • Age: Generally, most elderly individuals show some degree of varicose vein occurrence.
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