May-Thurner syndrome

  • May-Thurner syndrome occurs when the left iliac vein (the main blood vessel in the left leg that carries blood to the inferior vena cava and on to the heart) is compressed or narrowed by the right iliac artery (the main blood vessel that carries blood down the right leg). The compression of the left iliac occurs in the pelvic area.
  • May-Thurner syndrome increases your risk for deep vein thrombosis (DVT), a potentially serious blood clot that blocks blood flow in the vein. A DVT could break loose, travel through the bloodstream and cause blockage to your lung (pulmonary embolism).


May-Thurner syndrome typically does not show symptoms unless a DVT occurs:

  • Swelling
  • Pain, heaviness, leg throbbing
  • Redness or changes in skin color
  • Skin that feels warm to the touch


Your doctor will do a physical exam to check for DVT symptoms

Your doctor may order the following tests:

  • Trans-abdominal ultrasound
  • Computed tomography (CT)
  • CT venography (X-ray of the veins after a special dye is injected)
  • MR venography

Treatment for May-Thurner syndrome

  • Anticoagulants (blood thinners) in case of deep vein clots
  • Thrombolytic therapy in case of deep vein clots

Surgical treatments

  • Angioplasty
  • Inferior vena cava filters
  • Stent placement to open the narrowed part of the left iliac vein
  • Venous bypass surgery
  • Repositioning the right iliac artery so it does not compress the left iliac vein
Last reviewed: 
July 2017
Alternative Names: 
Iliac vein compression syndrome

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