Venous Thoracic Outlet Syndrome

Venous thoracic outlet syndrome (vTOS) is a squeezing or compression of your subclavian vein by nearby bone or muscle. This vein is between your chest and arm, at the base of your neck. Specifically, it’s between your collarbone (clavicle) and first rib. The subclavian vein carries blood from your arm back to your heart. The space where this vein runs through is called the thoracic outlet. This syndrome may also involve compression of your axillary vein.

People with vTOS often have arm soreness, heaviness, swelling or discoloration. They can also develop blood clots, which makes this condition serious.

This syndrome is rare. It’s one of the least common types of thoracic outlet syndrome.

Symptoms of venous thoracic outlet syndrome

Most people with this condition have symptoms that affect one arm and hand. You may have venous thoracic outlet syndrome symptoms like:

• Aching
• Blue or purple discoloration
• Heaviness
• Swelling
• Visible veins in one shoulder or arm, or on one side of your chest

Venous thoracic outlet syndrome causes

One cause of this condition is a naturally narrow passageway for the subclavian vein to run from your arm to your heart. You may have this if you were born with an abnormal first rib or extra (cervical) rib. You may also have a narrow space if you had severe trauma in the area, like a clavicle fracture.

If this space is tight, overusing your arm and shoulder can squeeze (compress) or aggravate the subclavian vein. This compression can block blood flow and lead to clots.

Other causes of venous thoracic outlet syndrome can include:

• Physical trauma, like injuries from a car accident or fall
• Repetitive overhead movements, like throwing a ball, lifting boxes overhead or swinging a baseball bat

Risk factors

Most people who get venous thoracic outlet syndrome are:

• In their 30s or younger
• Athletes who use repetitive motion in their arm and shoulder (baseball players or swimmers)
• Workers who move their arms overhead again and again

How to lower your risk

There’s no guaranteed way to avoid vTOS. But you can lower your risk of compression injuries by limiting repetitive overhead movements.

Complications of this condition

Venous thoracic outlet syndrome can be dangerous if you don’t get treatment. The compression from vTOS can cause blood clots to form in your subclavian vein. The clots can block blood flow in your arm or hand, or even to your lungs. A blood clot that moves to your lungs is a pulmonary embolism.

If you have symptoms of this syndrome, see a healthcare provider for a diagnosis. 

Seek emergency care if you have severe symptoms like chest pain, cough and shortness of breath that could point to a possible pulmonary embolism.

How doctors diagnose this condition

If you have vTOS symptoms, your healthcare provider will perform a physical exam and order imaging tests.

Your provider will:

• Look at your shoulder, neck and arm
• Ask you to move your arms in certain ways to check your range of motion
• Ask you about your symptoms
• Take your blood pressure

If your provider suspects vTOS, you may have more tests to examine your thoracic outlet. To view blood flow in your veins and internal structures, you may have:

• CT scan: Using multiple X-rays to create detailed images
• Ultrasound: Using sound waves to look inside your body, including viewing blood flow
• Venogram: Placing a small, hollow tube (catheter) and contrast dye in your veins before taking an X-ray
• X-ray: Using targeted, safe doses of radiation to get images (less commonly used)
• MRI: Using radio waves and magnets to get a detailed picture (less commonly used)

How is it treated?

Venous thoracic outlet syndrome treatment can include nonsurgical and surgical options. Your healthcare provider may use an IV or a tube (catheter) to give you medicine that breaks up a blood clot. They may use a venogram to give you thrombolytics or to remove the clot (mechanical thrombectomy).

They’ll also prescribe medications to dissolve blood clots. You may receive anticoagulants like warfarin (Coumadin®), heparin or direct oral anticoagulants (Xarelto® or Eliquis®).

After the clot breaks up, you may need surgery to prevent blood clots from happening again. During surgery, your provider may:

• Remove the first rib, scalene muscles and subclavius muscle
• Remove any extra bone, tissue or muscle around the subclavian vein
• Redirect blood flow to avoid damaged veins and restore circulation

You’ll likely spend one to three nights in the hospital after surgery. You’ll receive medicine for pain and learn simple exercises you can do at home to improve your range of motion.

If you have surgery, you’ll need to take anticoagulants afterward. You can expect to have an ultrasound two to four weeks after surgery. The results help your provider decide how long you need to keep taking anticoagulants.

When should I see my healthcare provider?

You can expect to have regular follow-up visits with your provider after treatment. Contact your provider between visits if the treatment doesn’t improve your symptoms.

Questions to ask your provider may include:

• What is the most likely cause of venous TOS symptoms?
• What tests do I need for diagnosis?
• What are the treatment options?
• Will nonsurgical treatments improve my symptoms?

What can I expect if I have this condition?

Without treatment, venous thoracic outlet syndrome can cause blood clots. But getting treatment within the first 14 days of symptoms greatly increases your chances of a successful outcome. If you have any signs of vTOS, see a healthcare provider right away.

The first step of treatment, breaking up blood clots with medicine, works well for most people. And surgery for vTOS (the second step) typically has high success rates. Most athletes who have surgery can return to their sport after they heal. Full recovery can take four to five months.