Iliac Vein Compression Syndrome (IVCS): An Overlooked Clinical Entity

Abstract

INTRODUCTION: We report a case of May-Thurner syndrome leading to extensive left lower extremity deep venous thrombosis (DVT). CASE PRESENTATION: A 39 year-old-male developed acute left leg pain and swelling after several long plane flights. He was diagnosed with an acute lower extremity DVT extending from the left external iliac vein through the left posterior tibialis vein and was started on IV unfractionated heparin. Due to extensive left leg pain and swelling, the patient was referred to vascular surgery for further management. The patient underwent catheter-directed thrombolysis and mechanical thrombectomy. After clearance of clot, venography demonstrated significant left common iliac vein stenosis, consistent with a diagnosis of May-Thurner Syndrome. Balloon angioplasty and stenting of the site were performed with 0% residual stenosis. Post-procedure, the patientaTMs lower extremity edema and pain markedly improved. Hypercoagulable work-up revealed protein C deficiency. The patient was discharged on warfarin with a recommendation for life-long anticoagulation. DISCUSSION: May-Thurner syndrome, or IVCS, has been described as compression of the left common iliac vein between the overlying right common iliac artery and the underlying vertebral body. The predilection for left lower extremity DVT was first reported by Virchow. A century later, May and Thurner described intraluminal spurs within the compressed left iliac vein that were hypothesized to predispose to left iliofemoral DVT formation. In fact, this anatomic pattern is seen in approximately 2-3% of normal adults, and, when associated with DVT, is often complicated by clot recurrence and/or post-phlebitic syndrome. Despite its prevalence, IVCS has often been overlooked as a cause of extensive DVT, and only recently with the use of endovascular therapies is it being diagnosed with increasing frequency. Unfortunately ultrasound of the lower extremities, and even CT venography, may not demonstrate the vascular compression. Magnetic resonance venography or endovascular venography are preferred methods of diagnosis, but these tests are not routinely ordered as part of a workup for lower extremity DVT. A randomized controlled trial by Plate et al demonstrated that in these patients, leg swelling and ulcers were nearly twice as common when patients were treated with anticoagulation alone versus anticoagulation plus surgical intervention. CONCLUSIONS: In patients with extensive left iliofemoral DVT, one should consider an anatomic cause such as IVCS, as medical management alone may not suffice.