May-Thurner Syndrome in Children

In the Pediatric Emergency Department, sometimes compression is a helpful thing (Chest Compressions, Epistaxis), and sometimes compression isn’t so good (Thoracic Outlet Syndrome, Tourniquet Syndrome, Cardiac Tamponade, Compartment Syndrome). A recent discussion with some colleagues about some interesting cases they have seen prompted me to remember this compression syndrome that I have seen a handful of times – May-Thurner Syndrome.  Don’t PRESS me for too much information, but I’ll see what I can SQUEEZE into a few short lines here:

May-Thurner Syndrome: Basics 

[Mangla, Mako, Poyyamoli, Fereydooni, Harbin]

  • Compression of the left common iliac vein (LCIV) between the right common iliac artery (RCIA) and the vertebrae, leading to thrombosis
    • There have also been reports of this being RIGHT sided as well.
    • Also known as “Cockett Syndrome” or “Iliac Vein Compression Syndrome” 
  • Occurs after the origination from the aorta and before the iliofemoral junction
  • Chronic endothelial irritation from pulsation of the overlying artery is theorized to cause “venous spurs” leading to fibrous band and clot formation.
  • It causes 2-5% of clinical DVTs, maybe even up to 49% of left sided DVTs.
    • Cadaveric studies show a higher prevalence (14-32%)
    • Female to male incidence is 2:1
    • May be asymptomatic with non-critical obstruction until a trigger, like pregnancy or surgery, causes worsening DVT.
  • Most common in 2nd and 3rd decades of life.

May-Thurner Syndrome: Presentation and Exam 

  • Unilateral swelling or leg pain [Mangla, Poyyamoli]
  • Sign/symptoms may be subtle: [Mangla, Poyyamoli]
    • Left leg tightness, mild swelling,
    • Telangiectasias, venous ulcers [Mangla, Poyyamoli]
  • Signs of chronic venous insufficiency: [Mangla, Poyyamoli]
    • Hyperpigmentation, lipodermatosclerosis, and recurrent skin ulcers
  • Three stages [Mangla, Mako]
    • Stage 1- compression without structural changes of vein. Asymptompatic.
    • Stage 2- Venous spur or fibrous connection restrict flow and increase risk for DVT and edema
    • Stage 3- Venous obstruction causing DVT, swelling, and varicose veins

May-Thurner Syndrome: Diagnosis 

[Mangla, Mako, Poyyamoli, Fereydooni ]

  • Ultrasound with Doppler
    • Most common technique used in the ED. First line evaluation.
    • Great at diagnosing DVTs
    • BUT, technically challenging to find iliac vein compression with Doppler alone
    • Not the ideal study.
  • CT Venography
    • 95% sensitivity and specificity to diagnose iliac vein compression
    • Can find other compression causes- hematoma, tumor, lympadenopathy
    • Can’t asses volume status, may overestimate degrees of compression in a dehydrated patient
  • Magnetic Resonance Venography
    • Single snapshot may not be enough to diagnose due to variable LCIV compression over time
    • Cost-prohibitive for some
  • Venography with intravascular ultrasound (IVUS)
    • Gold standard to date
    • Is invasive and now reserved for those going for endovascular treatment
  • Intravascular ultrasound (IVUS)
    • Gaining popularity and use
    • Real time evaluation of the vessel lumen
    • Can show chronicity of thrombus, helps with management decisions
    • Can localize guidewires during recanalizations
    • No contrast needed! Less contrast-related nephropathy and allergies!
  • Air Plethysmography (APG) [Mako]
    • Non-invasive method to quantify venous obstruction
    • Outflow fraction calculation

May-Thurner Syndrome: Treatment 

  • Acute thrombosis- catheter directed thrombolysis with endovascular stent placement [Mangla, Mako, Poyyamoli, Fereydooni ]
    • Vascular angioplasty isn’t good enough
    • Surgical thrombectomy is falling out of favor
      • Reserved for patients who fail endovascular methods
    • Bypass is rare but is an option.  [Mangla]
  • Anticoagulation with low molecular weight heparin, fondaparinux, or warfarin [Mangla]
    • Factor Xa inhibitors have been approved for use, but lack data for iliofemoral thrombosis.
    • Anticoagulation alone is not enough, though. The CaVenT trial and subgroup analysis of ATTRACT trial concluded that anticoagulation after catheter-directed thrombolysis was superior to anticoagulation alone. [Mangla, Poyyamoli]
    • Duration of anticoagulation is controversial and debated [Mako]

May-Thurner Syndrome: Complications 

  • Post-thrombotic syndrome– wear compression stockings!
  • Pulmonary embolism
  • Bleeding risks with anticoagulation medications
  • Rare: phlegmasia cerulea dolens– life threatening acute DVT complication with extreme swelling of the extremity with pain, cyanosis, and potentially arterial ischemia which leads to gangrene and need for amputation. [Mangla, Chaochankit]

Moral of the Morsel

  • For unilateral leg pain and swelling, you may need to look a little deeper to find your answer. The signs and symptoms may be subtle.
  • Venography with intravascular ultrasound is the gold standard for diagnosis, but CT venography has benefits.
  • Catheter directed thrombolysis, endovascular stent placement, and anticoagulation is the treatment of choice.
  • May-Thurner syndrome may be more common than you realize! Stay vigilant and consider LCIV compression!


  1. Mangla A, Hamad H. May-Thurner Syndrome. [Updated 2021 Oct 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from:
  2. Mako K, Puskas A. May-Thurner syndrome – Are we aware enough?. Vasa. 2019;48(5):381-388. doi:10.1024/0301-1526/a000775.
  3. Poyyamoli S, Mehta P, Cherian M, Anand RR, Patil SB, Kalva S, Salazar G. May-Thurner syndrome. Cardiovascular Diagnosis and Therapy. 2021;11(5):1104-1111. doi:10.21037/cdt.2020.03.07.
  4. Fereydooni A, Stern JR. Contemporary treatment of May-Thurner Syndrome. J Cardiovasc Surg 2021;62:447-55. DOI: 10.23736/S0021-9509.21.11889-0
  5. Harbin MM, Lutsey PL. May‐Thurner syndrome: History of understanding and need for defining population prevalence. Journal of Thrombosis and Haemostasis. 2020;18(3):534-542. doi:10.1111/jth.14707.
  6. Chaochankit W, Akaraborworn O. Phlegmasia Cerulea Dolens with Compartment Syndrome. Ann Vasc Dis. 2018;11(3):355-357. doi:10.3400/


Christyn Magill
Christyn Magill
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