What is May-Thurner syndrome (Iliac vein compression syndrome)?

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Last updated: May 28, 2025View editorial policy

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From the Guidelines

May-Thurner syndrome should be treated with anticoagulation therapy as the first line of treatment, and patients with an underlying anatomic compression syndrome amenable to intervention or surgery should have this addressed in addition to receiving anticoagulation therapy. This approach is based on the standard of care for iliofemoral venous thromboembolism (VTE) which emphasizes anticoagulation in patients without a contraindication 1. The treatment depends on symptom severity and complications, and for asymptomatic patients, regular monitoring may be sufficient. If deep vein thrombosis (DVT) has occurred, initial treatment includes anticoagulation therapy with heparin or low molecular weight heparin, followed by oral anticoagulants like warfarin, rivaroxaban, or apixaban for at least 3-6 months.

Some key points to consider in the management of May-Thurner syndrome include:

  • The use of cross-sectional imaging to assess for an underlying obstructive cause, such as a venous compression syndrome or mass 1
  • The role of ultrasound or CT in differentiating chronic from acute DVT 1
  • The potential benefits of endovascular interventions, such as catheter-directed thrombolysis, angioplasty, and stent placement, in addition to anticoagulation therapy 1
  • The importance of early diagnosis and appropriate treatment to prevent complications like post-thrombotic syndrome and pulmonary embolism

In terms of specific treatment options, anticoagulation alone is generally a first-line therapy for acute iliofemoral DVT, but patients with an obstructive iliac vein lesion may benefit from additional treatment with thrombectomy and iliac vein stenting 1. However, there is no relevant literature rigorously testing this practice against anticoagulation alone in prospective randomized controlled trials. Overall, the goal of treatment is to prevent complications and improve quality of life for patients with May-Thurner syndrome.

From the Research

Definition and Causes of May-Thurner Syndrome

  • May-Thurner syndrome (MTS) is an anatomical condition characterized by compression of the left common iliac vein by the right common iliac artery, causing venous outflow obstruction 2, 3, 4.
  • The compression of the left iliac vein between the right iliac artery anteriorly and the lumbar vertebrae posteriorly can lead to partial or complete impedance to the iliac vein outflow, resulting in deep vein thrombosis (DVT) 2, 4.

Clinical Presentations of May-Thurner Syndrome

  • Patients with MTS may remain asymptomatic or experience unilateral lower limb swelling and symptoms of DVT, such as redness and pain in the limb 2.
  • Clinical presentations can also include venous stasis ulcers, skin discoloration, and postphlebetic syndrome 4.
  • Pulmonary embolism is not a frequent association of MTS, but it can occur, even in asymptomatic patients 5.

Diagnosis and Treatment of May-Thurner Syndrome

  • Diagnosis of MTS can be made using duplex ultrasound, computer tomography venography, or magnetic resonance angiography 3, 4.
  • Treatment of MTS includes staged thrombolysis with/without prophylactic retrievable inferior vena cava filter placement, followed by angioplasty/stenting of the left iliac vein 4.
  • Anticoagulation therapy, including warfarin or novel oral anticoagulants such as rivaroxaban, may be used to prevent further complications 2, 6.
  • Endovascular treatment is preferred over anticoagulation alone, especially in otherwise fit patients presenting early, to reduce the chances of chronic venous hypertension in the lower limb 3.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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