May-Thurner Syndrome


What is May-Thurner Syndrome (MTS), also known as Iliac Vein Compression Syndrome?

May-Thurner syndrome (MTS) is caused when the left iliac vein is compressed by the right iliac artery, which increases the risk of deep vein thrombosis (DVT) in the left extremity. DVT is a blood clot that may partially or completely block blood flow through the vein.

When should I seek treatment for May-Thurner Syndrome?

Most people do not know they have MTS, but it is identified when they present with a DVT.
Patients should seek treatment for symptoms, including swelling, pain or tenderness in the leg, feeling of increased warmth in the leg, redness or discoloration of the skin, or enlargement of the veins in the leg.

Even though DVT itself is not life-threatening, the blood clot has the potential to break free and travel through the bloodstream, where it can become lodged in the blood vessels of the lung (known as a pulmonary embolism). This can be a life-threatening condition.

DVT can also lead to complications in the legs referred to as chronic venous insufficiency link (also known as post-thrombotic syndrome). This condition is characterized by pooling of blood, chronic leg swelling, increased pressure, increased pigmentation or discoloration of the skin, and leg ulcers known as venous stasis ulcer.

Management and Treatment

What are the treatment options for MTS?

The goals of treatment are to reduce symptoms and reduce the risk of complications. Your healthcare provider will recommend the treatment option that is right for you. Before choosing any treatment, it is important to discuss the potential benefits, risks and side effects with your healthcare provider. You will receive specific guidelines to help you prepare for your procedure, as well as specific instructions to help your recovery.

The majority of treatments related to MTS are actually geared toward treating the DVT that is associated with the vein compression. The following are a number of different options that may be employed to treat patients presenting with DVT.


Your physician may prescribe blood-thinning medication to prevent blood clots. When use of blood thinners is indicated, your physician will closely monitor you to ensure utmost safety. You may be referred to the Anticoagulation Clinic.

Catheter-directed thrombolytic therapy

This is a nonsurgical treatment that uses clot-dissolving medications, referred to as thrombolytics, to dissolve blood clots. The medications can be delivered via a catheter, a long slender tube that is guided through the vein to the segment where the blood clot is located. The clot-dissolving drug is infused through the catheter into the clot. The clot usually dissolves in a matter of hours to a few days. In some cases, the narrowed area of the vein will need to be treated with angioplasty to prevent further clots from forming.

Angioplasty and stenting

Angioplasty is a nonsurgical treatment option used to widen the vein after a blood clot has been dissolved. During angioplasty, a small balloon at the tip of the catheter is inflated to stretch the vein open and increase blood flow. A stent is often placed during the angioplasty procedure to keep the vein open. A stent is a small, metal mesh tube that acts as a scaffold and provides support inside the vein. A balloon catheter, placed over a guide wire, is used to insert the stent into the narrowed vein. Once in place, the balloon is inflated and the stent expanded to the size of the vein holding it open. The balloon is deflated and removed, and the stent stays in place permanently.

Stenting of the iliac vein is often important in the treatment of MTS. Once the blood clot is removed from the vein (typically by thrombolysis), the compressed vein is forced open with the use of a stent.

Vena cava filters

Vena cava filters may be a treatment option for select patients who cannot take anticoagulant (blood-thinning) medications, such as heparin, low-molecular weight heparin or fondaparinux, or for patients who are taking anticoagulants and continue to develop clots.Vena cava filters are not always used in the setting of MTS but are often used to treat complications associated with the development of a DVT. The filter can prevent blood clots from moving from the vein in the legs to the lung (pulmonary embolism). During a surgical procedure, the filter is inserted through a catheter (thin tube) into a large vein in the groin or neck, then into the vena cava (the largest vein in the body). It can catch clots as they move through the body to the lungs.

This treatment will help reduce the risk of a pulmonary embolism, but will not prevent the development of more clots.

More information about vena cava filters.

Outlook / Prognosis

What outcomes can I expect from treatment?

Outcomes of treatments for MTS are generally very good. Most patients, if identified shortly after the DVT has formed, can be adequately treated with complete resolution of his/her symptoms. Your healthcare provider will be able to provide more detail.


Doctors vary in quality due to differences in training and experience; hospitals differ in the number of services available. The more complex your medical problem, the greater these differences in quality become and the more they matter.

Clearly, the doctor and hospital that you choose for complex, specialized medical care will have a direct impact on how well you do. To help you make this choice, please review our Miller Family Heart, Vascular & Thoracic Institute Outcomes.

Cleveland Clinic Heart, Vascular & Thoracic Institute Vascular Medicine Specialists and Surgeons

Choosing a doctor to treat your vascular disease depends on where you are in your diagnosis and treatment. The following Heart, Vascular & Thoracic Institute Sections and Departments treat patients with all types of vascular disease, including blood clotting disorders:

Section of Vascular Medicine: for evaluation, medical management or interventional procedures to treat vascular disease. In addition, the Non-Invasive Laboratory includes state-of-the art computerized imaging equipment to assist in diagnosing vascular disease, without added discomfort to the patient. Call Vascular Medicine Appointments, toll-free 800-223-2273, extension 44420 or request an appointment online.

Department of Vascular Surgery: surgery evaluation for surgical treatment of vascular disease, including aorta, peripheral artery, and venous disease. Call Vascular Surgery Appointments, toll-free 800-223-2273, extension 44508 or request an appointment online.

You may also use our MyConsult second opinion consultation using the Internet.

The Heart, Vascular & Thoracic Institute also has specialized centers and clinics to treat certain populations of patients:

Learn more about experts who specialize in the diagnosis and treatment of vascular and arterial disease.


If you need more information click here to contact us, chat online with a nurse or call the Miller Family Heart, Vascular & Thoracic Institute Resource & Information Nurse at 216.445.9288 or toll-free at 866.289.6911. We would be happy to help you.

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Last reviewed by a Cleveland Clinic medical professional on 05/03/2019.

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