Venous Thoracic Outlet Syndrome (VTOS)

This condition is also known as Effort Thrombosis or Paget-Schroetter Syndrome.  While venous thoracic outlet syndrome can coincide with NTOS, it often presents independently. VTOS often affects “overhead” athletes. Patient presents with classic findings of blood clots in subclavian and arm vein on affected side. Common symptoms are bluish color and swelling of arm and shoulder with pain. 

Symptoms of Venous Thoracic Outlet Syndrome


  • Sudden arm swelling in an otherwise healthy and active person.
  • Arm swelling with bluish color changes and pain.
  • Shortness of breath with any above symptoms.
  • Prominent veins around neck and shoulder with above symptoms. 


Cause of Venous Thoracic Outlet Syndrome 

VTOS is caused by chronic compression and subsequent scarring of subclavian vein between collarbone (clavicle) and 1st rib (see picture below with blue arrow). Repetitive use of upper extremity leads to scar formation around the vein that ultimately causes blood clot to form. Some patient also have undetected clotting disorders that put them at further risk for Venous Thoracic Outlet Syndrome.


VTOS illustration provided by G.Sheng MD, St.Vincent Medical Group.

Diagnosis of Venous Thoracic Outlet Syndrome


  • Ultrasound of arm vein
  • CT scan of chest 
  • Contrast study through vein 


Treatment of Venous Thoracic Outlet Syndrome

VTOS is treated urgently with blood thinners. This prevents blood clot from going to lungs, also known as pulmonary embolism. Also the blood thinner keeps extension of clots to small veins in arm.  The immediate treatment for VTOS is dissolving the clot using a catheter. This procedure is known as catheter directed thrombolysis. Once the blood clot is fully dissolved, surgical removal of 1st rib is usually recommended to prevent future development of blood clot and to open collapsed vein.

Long term outcome of Venous Thoracic Outlet Syndrome

The overall outcome with treatment of VTOS is very good. Greater than 95% of the patients are able to resume normal use of their arms without any swelling. The rest of the patients may experience mild swelling with vigorous use of that arm. Majority of our patients are off the blood thinner within three months.