May-Thurner syndrome (ECR 2019 Case of the Day)

A 18-year-old female volleyball player presented with a left swollen inferior extremity that got worse after physical efforts.

Patient underwent contrast-enhanced MRI due to suspected obstructed venous or lymphatic flow. Contrast-enhanced MRI showed compression of the left common iliac vein (LCIV) between the right common iliac artery (RCIA) and the spine. The patient undewent phlebography of the left lower extremity, which confirmed a 70%-stenosis of the LCIV, that was accurately estimated also with IVUS before treatment (Fig.1). A 3D volume-rendered CT reconstruction of the venous stenotic tract explicitly depicted the anatomical changes of May-Thurner syndrome, providing an impressive view for treatment planning (Fig.2). Due to the increasing discomfort after unsuccessful lymphatic drains, patient was considered for endovascular therapy. Stenting with a 16x9mm bare-metal stent (Wallstent, Boston Scientific, Marlborough, USA) was therefore performed. Angiography and post-procedural IVUS confirmed the successful stent placement (Fig.3).

May-Thurner syndrome is a commonly undiagnosed condition affecting up to 20-40% of the patients with deep vein thrombosis. Chronic pulsations of the right common iliac artery upon the left common iliac vein that are thought to cause the development of obstructing fibrotic scars inside the vein. Typical clinical presentation is recurrent deep venous thrombosis, leg edema, chronic pain and phlebitis. An increased incidence has been noted in women in their twenties to forties [1]. Diagnosis depends on the clinical presentation of left lower extremity pain and swelling. It’s important to underline that demonstration of a consistently narrowed iliac vein is essential. This should be demonstrated regardless of volume status and patient positioning because since fibrotic spurs are irreversible. A first imaging evaluation include Doppler ultrasound to detect DVT. Other modalities include computed tomography (CT), CT venography, magnetic resonance venography, IVUS, and conventional venography that represents the gold standard. Magnetic resonance imaging (MRI) is a useful modality as it can rule out the presence of a pelvic mass, DVT, and demonstrate the anatomy of the syndrome. Treatment for MTS involves clearing the thrombus and correcting the compression of the left iliac vein. Endovascular intervention with thrombolysis and stenting is considered the first line treatment for MTS. Catheter-directed thrombolysis could be performed, in which urokinase or tissue plasminogen activator (tPA-alteplase) is administered locally at the site of the thrombus [2]. Written informed patient consent for publication has been obtained.