For Patients

May Thurner Syndrome (MTS)

What is it?

May-Thurner Syndrome (MTS) is a condition caused by the compression of the left common iliac vein by the right iliac artery leading to development of fibrosis (much like scar tissue) that results in narrowing of the vein. Different pelvic veins can be compressed at different points by segments of the artery or by overlying structures such as an enlarged uterus.

What are the common symptoms?

Some patients whose iliac veins are narrowed by 50% or more will develop some of the following symptoms including; leg pain (mostly after standing for an extended period of time or after exercise), swelling (oedema), pelvic pain, pain with intercourse (dyspareunia), pelvic pain after intercourse (post-coital pain), lower back pain, urinary bladder or bowel symptoms, bloating, leg veins, vulvar varicosities/varicocele or hemorrhoids.

What is the association with blood clots?

Some people who have a narrow iliac vein are more prone to developing thrombosis (clots) if they have additional risk factors for clotting such as being on oral contraceptives or estrogen therapy, pregnancy, extended periods of sitting or certain inherited disorders which increase the risk of abnormal clotting such as Factor V Leiden mutation, Factor II Prothrombin mutation, Protein S or Protein C deficiency or Anti-Thrombin III deficiency. This is known as iliofemoral deep vein thrombosis.  Iliofemoral deep vein thrombosis usually presents with a sudden onset of leg pain, swelling and a blue discoloration of the leg.  Roughly 80% of patients who develop iliofemoral deep vein thrombosis involving the iliac and leg veins will be found to have an iliac vein narrowing.

What are your treatment options?

When an iliac vein narrowing (stenosis) is discovered, this can be treated with placement of a stent in the vein.  The stent is inserted into the compressed iliac vein by a needle stick approach in the groin.  The stent usually yields impressive improvements in the quality of life for those who have severe symptoms from iliac vein compression.