May-Thurner Syndrome

An estimated 20% of the U.S. population have a vascular disorder known as May-Thurner Syndrome. It involves impingement of the main vein that travels into the left leg. This can cause mild to severe symptoms and complications as a result.

The primary concern of this condition is that it can lead to the formation of deep vein thrombosis, a blood clot in the deep veins of the legs than can become life-threatening should it travel to the lungs, triggering a pulmonary embolism.

What Is May-Thurner Syndrome?

May-Thurner Syndrome (MTS) involves an abnormality in the crisscross of arteries and veins in the pelvic region. It occurs when the right iliac artery compresses the left iliac vein that travels down into the left leg. This can constrict the vein, cause scarring, and increase your risk of developing blood clots and deep vein thrombosis (DVT) in left lower leg. For this reason, MTS is sometimes called iliac vein compression syndrome.

Symptoms & Complications

In many cases, those with the syndrome have no symptoms and may be unaware they have the condition. For them, the vein compression is slight and causes no noticeable symptoms. However, the

condition may progress from an asymptomatic stage as more severe compression of the vein occurs.

Often, by the time symptoms appear, it is likely that complications due to May-Thurner Syndrome – such as varicose veinsedema (swelling due to fluid buildup), and blood clots – have already occurred. Thus, the symptoms experienced are really symptoms of the complications of the condition.

Symptoms that occur tend to focus on the left leg and may include:

  • Generalized pelvic pain
  • Leg cramps
  • Heaviness in the leg
  • Leg pain and swelling
  • Pain that increases when standing or walking and decreases when legs are elevated
  • Noticeably enlarged veins in the leg
  • Discoloration in the skin of the leg
  • Nonhealing leg wounds

If symptoms occur, it may begin following a pregnancy or a period of immobility.

Who Is at Risk?

May-Thurner Syndrome is not passed down in families, but it does appear to be a structural abnormality that a person may be born with. It occurs in women far more often than men. The following are associated with an increased risk of symptomatic May-Thurner Syndrome:

  • Women 20 – 45 years old
  • Prior pregnancy
  • Women using hormonal birth control methods
  • Prolonged periods of inactivity