May-Thurner syndrome (MTS) is a type of vein disease that is difficult to diagnose but can have a significant impact on the health of the veins. This condition increases a person’s risk of developing deep vein thrombosis (DVT), a type of blood clot that if left untreated can be potentially life-threatening.
DVT related to May-Thurner syndrome is most common in women between the ages of 20 and 40, especially after pregnancy or following an extended period of inactivity.
It’s hard to know how many people get May-Thurner syndrome, because most cases don’t have any symptoms. However, it is estimated between two and five percent of all individuals suffering from vein disorders in the lower extremities have May-Thurner syndrome.
The Vein Clinic at Novus Spine & Pain Center in Lakeland, Florida specializes in diagnosing and treating May-Thurner syndrome, which is named after the physicians who first described the phenomenon in 1957, R. May and J. Thurner.
In This Article:
- What is May Thurner Syndrome?
- What Causes May Thurner Syndrome?
- What are the Symptoms of May Thurner Syndrome?
- How is May Thurner Syndrome Diagnosed?
- How is May Thurner Syndrome Treated?
- Novus Spine & Pain Center
- May Thurner Syndrome Resources
What is May-Thurner Syndrome?
To understand May-Thurner syndrome, it is important to understand the anatomy of blood flow in the body. Blood vessels carry blood to every part of the body. Arteries move blood away from the heart, while veins return blood to the heart.
May-Thurner syndrome is also known as iliac vein compression syndrome, iliocaval compression syndrome, or Cockett syndrome. The syndrome affects two blood vessels in the legs, resulting in a significant risk of developing a deep vein thrombosis (DVT) in the left leg.
This condition involves the right iliac artery, which carries blood to the right leg, and the left iliac vein, which brings blood out of the left leg on its way back toward the heart. In the pelvis, the right iliac artery naturally crosses the left iliac vein. The close proximity of these blood vessels, in people with May-Thurner syndrome, leads to the artery placing pressure on the vein. The pressure causes the vein to become pinched between the artery and vertebrae in the back. The exact cause of this increased compression is unclear.
The added pressure leaves a narrower opening and prevents blood from flowing as freely through the left iliac vein. The result is similar to stepping on a garden hose; if the pressure is severe enough, it can restrict the blood flow. This condition can lead to blood pooling (statis) and allow blood clots to form. The pressure can also cause scarring in the vein. If clots form, they can create a deep vein thrombosis (DVT) in the left leg, which is a type of blood clot that can be very serious.
Recently, the May-Thurner syndrome definition has been expanded to a broader disease profile known as nonthrombotic iliac vein lesions (NIVL) which can involve both the right and left iliac veins as well as multiple other blood vessels.
What Causes May-Thurner Syndrome?
May-Thurner syndrome is random. It is an anatomic variant people are born with, but it is not an inherited trait. The condition is thought to be related primarily to a congenital condition, which may cause an aberration in the arrangement of the left iliac vein and the right iliac artery. The condition may also develop as a result of trauma, and the likelihood may increase with age and extreme weight gain.
While May-Thurner syndrome causes a DVT in some people, other people experience no problems and the syndrome goes unnoticed and undiagnosed.
What are the Symptoms of May-Thurner Syndrome?
People with May-Thurner syndrome most likely don’t even know they have it unless they develop a DVT. In fact, many people with May-Thurner syndrome have no symptoms, even if there is a pronounced narrowing of the iliac vein, because smaller veins that bypass the narrowed area enlarge and drain the blood from the leg vein very efficiently. These bypassing veins are called “collaterals.”
Some people with severe vein narrowing experience leg swelling and pain that is often described as chronic venous insufficiency. However, there usually aren’t any warning signs. If pain develops, it is most noticeable when the affected limb hangs down from the edge of a bed or chair. There is also significant swelling of the whole limb.
With a DVT, your left leg may show symptoms such as:
- Changes in skin color – appearing more red or purple than normal.
- Heaviness, tenderness, or throbbing in the leg.
- Leg pain that feels like a cramp or charley horse.
- Leg ulcers.
- Skin that feels warm to the touch.
- Swelling in the leg.
- Veins that look larger than usual on the leg.
If a piece of a DVT breaks off and travels to the lung, it can cause a pulmonary embolism (PE). A PE can be a life-threatening medical emergency. Seek immediate medical attention should you notice any symptoms of a PE:
- Chest pain that’s worse when breathing in.
- Coughing up blood.
- Fainting or passing out.
- Hard to breathe or shortness of breath.
- A heartbeat that’s faster than normal.
How is May-Thurner Syndrome Diagnosed?
May-Thurner syndrome’s lack of symptoms makes it difficult to diagnose. After a physical exam, May-Thurner syndrome can only be definitively diagnosed by imaging the lower back and pelvic area, using techniques which may include:
- Computerized Tomography (CT or CAT). A scan using computers and rotating X-ray machines to create cross-sectional images of the body. These images provide more detailed information than normal X-ray images and show soft tissues, blood vessels, and bones.
- Intravascular ultrasound (IVUS). A test using sound waves to create moving images of blood flowing through the veins and arteries. Unlike an X-ray, an ultrasound does not use radiation.
- Magnetic Resonance Imaging (MRI). Using magnets and radio waves, an MRI captures images inside the body without making a surgical incision. An MRI scan allows visualization of the soft tissues of the body, such as muscles and organs, without bones obstructing the view.
- Venography. A special dye is injected into the vein prior to taking X-ray images of the area. The dye allows the veins to show up on X-ray, revealing any compressed areas, as well as areas of sluggish blood flow which can indicate the presence of a clot.
- Venous Occlusion Plethysmography. A non-invasive test to evaluate the venous system particularly deep veins in the legs.
- X-ray. A standard imaging test in use for decades to help the doctor view inside the body without having to make an incision.
How is May-Thurner Syndrome Treated?
May-Thurner syndrome only requires treatment if a DVT starts to produce symptoms. To prevent prolonged swelling and pain, blood flow must be improved through the leg. In less serious cases, MTS can be managed with compression stockings. However, the most commonly prescribed treatments for May-Thurner syndrome are to resolve the symptoms and risks associated with the DVT.
The two primary goals of treating a DVT are to treat existing clots and to keep new ones from forming. Most of the options for treating a DVT is the administration of anticoagulants (blood thinners). There are several options available, including:
- Blood thinners. Drugs commonly used to treat DVTs. The drug helps prevent new clots and keeps existing ones from getting bigger. These medicines are called anticoagulants.
- Clot busters (Thrombolysis). For more serious clots, the doctor uses a thin tube (catheter) to put medication directly on the clot. The drug typically breaks down the clot in a few hours to a few days.
- Pharmacomechanical thrombolysis. A more recent technique using a combination of clot-dissolving drugs and a device that breaks the clot apart mechanically. Often, aggressive treatment of the compressed vein is recommended following thrombolysis. The most common procedures are a stent or angioplasty.
- Angioplasty and a stent. The doctor uses a small balloon to expand the left iliac vein (angioplasty), then inserts a stent. The stent is a tiny cylinder, made of metal mesh, which keeps the vein open so blood can flow normally. The stent procedure is safe, effective, and does not result in significant downtime for the patient.
- Vena cava filter. For patients when blood thinners are not a good option, the doctor places a filter in the vena cava (large vein in the belly). Although the filter doesn’t prevent clots from forming, it catches the clot before it reaches the lungs if it breaks loose.
- Bypass surgery. The doctor builds a new path for the blood to flow. It is like a detour around the part of the left iliac vein that’s being squeezed.
- Surgery to move the right iliac artery. An operation to shift the position of the artery, so it sits behind the left iliac vein.
- Tissue sling. With this surgery, a piece of tissue is placed as a cushion between the two blood vessels.
Some of the surgeries associated with May-Thurner syndrome are done on an outpatient basis, allowing the patient to go home the same day after the procedure. Depending on the procedure, the patient should be able to return to normal activities within a few days to a week. The doctor may also recommend lifestyle changes the patient can make to reduce the risk of developing new clots.
Novus Spine & Pain Center
Novus Spine & Pain Center is in Lakeland, Florida, and specializes in diagnosing and treating May-Thurner syndrome. By using a comprehensive approach and cutting-edge therapies, we work together with patients to restore function and regain an active lifestyle, while minimizing the need for opiates.
May-Thurner Syndrome Resources
What is May-Thurner Syndrome? (WebMD)
4 Important Things You Need to Know About May-Thurner Syndrome (Vein Directory.org)
May-Thurner Syndrome (Cleveland Clinic)
May–Thurner Syndrome (Wikipedia)
May-Thurner Syndrome (Healthline)
May-Thurner Syndrome (National Blood Clot Alliance/StopTheClot.org)
May-Thurner Syndrome (ClotConnect.org)
Intervascular Ultrasound (MedlinePlus.gov)
Venous Occlusion Plethysmography (Medis)
Image credit: Wikimedia