May-Thurner Syndrome (MTS)

May-Thurner Syndrome (MTS), or iliac vein compression syndrome, is an anatomical variant characterized by the compression of the left common iliac vein between the right common iliac artery and the fifth lumbar vertebra. While often asymptomatic, it can predispose individuals to left lower extremity deep vein thrombosis (DVT), chronic venous insufficiency, and pelvic congestion syndrome due to chronic pulsatile compression, intimal hyperplasia, and subsequent venous outflow obstruction.

At Stanford Children's Health, the Pediatric Interventional Radiology team offers comprehensive expertise in the diagnosis and endovascular management of MTS in pediatric and adolescent populations. Utilizing state-of-the-art imaging modalities, including advanced venography and intravascular ultrasound (IVUS), our specialists precisely delineate the degree and location of venous compression and associated thrombus. Treatment strategies often involve catheter-directed thrombolysis for acute DVT, followed by percutaneous transluminal angioplasty and stent placement to relieve the underlying venous outflow obstruction. Our multidisciplinary approach ensures optimal patient outcomes, emphasizing minimally invasive techniques to reduce morbidity and facilitate rapid recovery in this young patient cohort.

Example: 17-year-old female who presented with acute deep vein thrombosis (DVT) of left lower extremity.

US of the popliteal vein shown here shows no flow. The thrombus extended to the pelvis. Below the knee was not imaged.
 

	CT Venogram from outside institution without definite findings of May-Thurner syndrome
	Venogram of the calf from the left posterior tibial vein (PTV) shows complete occlusion of the PTV with collateral flow into the peroneal vein and tibio-peroneal trunk, which both contain nonocclusive thrombus.
	After accessing the right internal jugular vein, venography of the pelvis shows the upper extent of the thrombus in the common iliac vein.

	Venography 48 hours later shows extensive residual thrombus, despite significant symptomatic improvement. tPA dose reduced by 50% due to low fibrinogen (<100) and lysis was continued
	Follow-up imaging 2 months later: May-Thurner (left common iliac vein compression) syndrome
	Stent deployment: Venovo 14 mm x 60 mm
	Post-stenting venoplasty: Conquest  14 mm x 6 cm

Post-procedure: started on therapeutic lovenox then converted to Xarelto at 6 weeks

IR RN telephone call 1.5 weeks later:

• Leg swelling-resolved by 80% since procedure
• Calf swelling- resolved by 80% since procedure
• Returned to school and  regular normal activities