May-Thurner Syndrome (MTS) is a vascular condition that occurs when the left iliac vein becomes compressed by the right iliac artery, restricting blood flow and increasing the risk of deep vein thrombosis (DVT), leg swelling, and chronic discomfort. Many individuals with undiagnosed leg pain, heaviness, or unexplained swelling may be suffering from this condition without realizing it. If left untreated, MTS can lead to serious complications, including the formation of dangerous blood clots in the lower extremities.
At Vascular Surgery Associates, our team of expert vascular specialists in Los Angeles and Santa Monica provides advanced diagnostic imaging and minimally invasive treatments to help restore proper blood flow and prevent long-term complications.
What is May-Thurner Syndrome?
May-Thurner Syndrome is caused by the anatomical compression of the left iliac vein by the right iliac artery, which crosses over it in the pelvis. This vein compression restricts normal blood flow, leading to chronic venous insufficiency, swelling, and clot formation in the left leg. While many people may have this anatomical variation without symptoms, others experience leg discomfort, heaviness, and DVT due to the restricted circulation.
Studies estimate that May-Thurner Syndrome affects 2-5% of the population, but it is often underdiagnosed because its symptoms can be mistaken for other venous conditions. Recognizing the warning signs and seeking expert vascular evaluation is crucial to preventing complications.
Signs & Symptoms of May-Thurner Syndrome – When to Seek Treatment
Many people with MTS go undiagnosed for years, as symptoms can be mild or mistaken for other circulatory conditions. However, persistent leg discomfort or swelling should not be ignored. Common signs of May-Thurner Syndrome include:
- Unilateral leg swelling (most often in the left leg)
- Heaviness or aching in the leg, especially after prolonged sitting or standing
- Skin discoloration or visible veins in the affected leg
- Pain or tenderness in the leg, particularly in the calf
- Recurring deep vein thrombosis (DVT)
Without treatment, May-Thurner Syndrome can increase the risk of chronic venous insufficiency, post-thrombotic syndrome, and life-threatening pulmonary embolism. Early detection and intervention can prevent complications and restore proper circulation.
What Causes Vein Compression?
May-Thurner Syndrome is primarily an anatomical condition, meaning some people are simply born with a vein structure that predisposes them to compression. However, certain factors can make symptoms worse or increase the risk of developing complications:
- Prolonged immobility (long hours of sitting or standing)
- Pregnancy and hormonal changes that increase vein pressure
- Obesity or weight gain that places added strain on pelvic blood flow
- Surgical history or trauma that affects vascular structures
- History of deep vein thrombosis (DVT) or previous blood clot formation
Women between the ages of 20 and 50 are more likely to develop symptomatic May-Thurner Syndrome due to hormonal influences, pregnancy-related vascular changes, and increased blood volume.
How is May-Thurner Syndrome Diagnosed?
Because MTS symptoms mimic other vein conditions, an accurate diagnosis is essential. At Vascular Surgery Associates, we use state-of-the-art vascular imaging to evaluate blood flow, vein compression, and clot formation.
Doppler Ultrasound
Evaluates blood circulation and detects blockages or abnormal flow patterns
CT Venography (CTV) & MR Venography (MRV)
Provide detailed imaging of the iliac vein and surrounding structures
Intravascular Ultrasound (IVUS)
Is a minimally invasive catheter-based imaging technique that provides real-time assessment of vein compression
These advanced diagnostic tools allow our specialists to confirm the severity of MTS and develop a personalized treatment plan.
Minimally Invasive Treatments for May-Thurner Syndrome
At Vascular Surgery Associates, we specialize in cutting-edge, minimally invasive procedures that restore blood flow and reduce the risk of DVT, chronic swelling, and post-thrombotic complications.
Venous Stenting – Restoring Proper Blood Flow
The most effective treatment for May-Thurner Syndrome is venous stenting, a minimally invasive procedure that opens the compressed vein and improves circulation. The procedure involves:
- A catheter-guided balloon angioplasty to widen the narrowed iliac vein
- Placement of a self-expanding stent to keep the vein open and prevent future compression
- Immediate improvement in blood flow and symptom relief
Venous stenting is performed as an outpatient procedure with minimal downtime and fast recovery, making it an excellent option for long-term symptom relief.
Catheter-Directed Thrombolysis – Treating Blood Clots Caused by MTS
If DVT has already formed, catheter-directed thrombolysis may be necessary to dissolve the clot before placing a stent. This procedure involves:
- Guided delivery of clot-dissolving medication (thrombolytics) directly into the clot
- Use of a specialized device to break up and remove the clot
- Immediate restoration of blood flow and prevention of further complications
Once the clot is resolved, venous stenting can be performed to prevent recurrence.
Frequently Asked Questions About May-Thurner Syndrome
While MTS itself is not life-threatening, it significantly increases the risk of deep vein thrombosis (DVT), which can lead to serious complications like pulmonary embolism if left untreated.
Without treatment, vein compression can worsen, leading to chronic swelling, leg ulcers, and post-thrombotic syndrome, which causes long-term discomfort and vein damage.
If you have persistent leg swelling, unexplained pain, or a history of blood clots, a vascular evaluation is recommended to determine if May-Thurner Syndrome is the cause.
Venous stents are designed to be long-lasting and prevent future vein compression, but routine follow-ups ensure proper function over time.
While stenting is the most effective treatment, maintaining a healthy weight, staying active, and wearing compression stockings can help support better vein health.
Dedicated to Excellence in Vascular Care Since 1963
Vascular Surgery Associates (VSA) has established itself as a cornerstone of vascular health in Southern California, combining decades of experience with cutting-edge treatment methods. Founded by visionary surgeons in 1963, our practice has grown from pioneering beginnings into one of the busiest and most respected vascular surgery groups in the Western United States.
Specialized May-Thurner Syndrome Treatment in Los Angeles & Santa Monica
May-Thurner Syndrome is often overlooked as a cause of leg swelling and discomfort, but early diagnosis and treatment can prevent serious complications. At Vascular Surgery Associates, our vascular specialists in Los Angeles and Santa Monica offer expert evaluation, minimally invasive treatment options, and long-term care strategies to ensure optimal circulation and symptom relief.
Contact us today to schedule a consultation and take control of your vascular health.