What is May-Thurner syndrome?

Written by Arthur Kao and Bradley Hill, M.D.

What is May-Thurner syndrome?

May-Thurner syndrome, also known as iliac vein compression syndrome or Cockett’s syndrome, occurs when the right iliac artery compresses the left iliac vein near the pelvis which results in a partial blockage preventing proper blood flow through the vein. Dr. Hill encounters many cases of May-Thurner syndrome, a syndrome which commonly leads to cases of deep vein thrombosis (DVT). DVTs are blood clots that originate in the legs and can be very dangerous when they break up and travel to the lungs causing pulmonary embolisms in which one quarter of PE cases result in sudden deaths.

How May-Thurner syndrome works

Because May-Thurner syndrome typically affects the left iliac vein, the left lower extremity is usually the body part most affected, however there have been rare reports that it also affects the right side. Arteries move blood away from the heart and are generally thick and elastic to accommodate for the high pressure blood flow exiting from each heart contraction. Veins, on the other hand. move blood back to the heart and are generally thinner and compressible. The pressure of the blood flow of a vein is far less than that of an artery. The prevention of proper blood flow through the vein caused by the iliac artery compressing the iliac vein significantly increases the chance of blood clots forming and makes it hard for blood to circulate back to the heart.

Symptoms and signs of May-Thurner syndrome

Interestingly, the syndrome itself is hard to detect because of the lack of symptoms aside from pain and swelling. It is usually the development of a DVT and its symptoms which leads to the diagnosis of May-Thurner syndrome. DVT symptoms include:

• Red/purple skin discoloration
• Heaviness, tenderness, and throbbing of the leg
• Swelling
• Enlargement of veins
• Venous ulcers that do not heal
• Chronic venous insufficiency
• Leg pain that has a cramping feeling

Individuals at risk for May-Thurner syndrome

            While May-Thurner syndrome is not inherited, it can be congenital and can develop later on in an individual’s life. There are certain factors in the population that place individuals at higher risk of being diagnosed with May-Thurner syndrome. Females have a higher incidence of developing the syndrome; they are twice as likely to develop May-Thurner than males. For females, factors such as pregnancy and the use of oral contraceptives put them at risk for the formation of blood clots and ultimately the development of May-Thurner syndrome. Other factors that contribute to the risk of developing May-Thurner syndrome include:

• Having scoliosis
• Dehydration
• Other conditions that cause blood clots

Current methods of diagnosis and treatment for May-Thurner syndrome

            As mentioned above, May-Thurner syndrome can be hard to detect with its lack of symptoms prior to a DVT but many different imaging techniques can be used to diagnose May-Thurner. Computerized tomography (CT) scans can be used to identify the presence of May-Thurner by generating multiple X-ray images taken at different angles to produce cross sectional images of tissues, bones, and blood vessels. Another type of X-ray that can diagnose May-Thurner is a venogram where a contrast dye is injected into the vessels to visualize blood flow through them. Magnetic resonance imaging (MRI) can also be used to diagnose May-Thurner syndrome by using strong magnetic fields and radio waves to generate images of organs and tissues. Ultrasound imaging uses high frequency sound waves to generate images inside the body. Intravenous ultrasound (IVUS) specifically is an invasive technique that uses a catheter to image the inside of blood vessels and assess the diameter of the blood vessel at the desired location.

            Treatment for May-Thurner syndrome can range from non-invasive preventative treatments to invasive surgical techniques for treatment. Treatments include:

• Angioplasty and stent – Angioplasty is a procedure used to widen the diameter of the left iliac vein. The procedure utilizes a catheter and commonly IVUS to visualize the diameter of the vein and position the stent, a metal mesh cylinder shaped device to keep the vein open.
• Bypass surgery – Bypass surgery is a procedure used to create a new path for the blood to flow instead of having the blood flow through the compressed iliac vein.
• Blood thinners – Blood thinner drugs are used to treat and prevent the formation of DVTs by reducing the ability for the blood to clot. Examples of blood thinners include Xarelto and Eliquis.
• Clot busters – This technique is used to treat more serious blood clots. Like the blood thinner treatment, medication is used to break up the clot but in this case a catheter is used to guide and deliver the medication to break up the clot within hours. The type of drug used in this treatment is called TPA.
• Compression stockings – Compression stockings are used as a preventative lifestyle measure for those who have a more mild case of May-Thurner syndrome. The tight pressure from these stockings eases swelling of the affected leg and improves blood flow as well.
• Surgery to move iliac artery – This surgical procedure moves the iliac artery behind the iliac vein so the artery is now in between the vein and the pelvis. The iliac artery will no longer be in position to compress the iliac vein after the procedure.
• Vena cava filter – The vena cava filter treatment is an alternative for individuals who cannot undergo the blood thinner and clot buster treatment. A filter is placed in a vein in the individual’s belly to prevent blood clots from traveling up to the lungs where it becomes a pulmonary embolism. This treatment itself does not prevent clots from forming in the first place.

At Hill Vascular and Vein Center, Dr. Hill is able to safely and effectively treat May Thurner syndrome in our accredited surgery facility. Our facilities offer a comfortable and quiet space for patient to receive care away from the busy hospital setting. If you or your loved one has been recently experiencing any of these symptoms or has been recently diagnosed with May Thurner syndrome, call Dr. Hill for more information.