May-Thurner Syndrome: An often-unrecognized cause of Lower Extremity Deep Venous Thrombosis

May-Thurner Syndrome: An often-unrecognized cause of Lower Extremity Deep Venous Thrombosis Karina Cardenas, M.D., General Surgery, East Florida GME Consortium Shaikh Hai, M.D., Marek Zalewski, M.D. Introduction.Outflow tract obstruction as a result of venous compression, is known as May-Thurner syndrome, originally described in 1957. Anatomically it is more frequently seen in the left lower extremity, where the left common iliac vein is compressed by the overlying right common Iliac artery. Extrinsic compression of the LCIV can lead to stenosis resulting in venous hypertension. Symptoms of venous stasis can include skin discoloration, pain, swelling, varicose veins and predisposition to DVT. Case Description.A 64-year-old female presented with progressively debilitating left leg discomfort, swelling and erythema for the past week. Her past medical history was significant for breast cancer, diabetes, hypertension, coronary artery disease, morbid obesity and smoking. A left leg venogram showed occlusion of the common femoral vein, external iliac vein and extending to the LCIV. She was systemically anticoagulated and mechanical thrombectomy was performed to reduce clot burden. An ultrasound assisted thrombolytic catheter was positioned distally and left for 24 hours with an Alteplase drip. However, this led to only partial recanalization of the organized thrombus on the follow-up venogram, and a coated stent was deployed in the entire LCIV, extending to the proximal left external iliac vein. Discussion.There are no universally accepted criteria to diagnose May-Thurner syndrome which is responsible for about 5% of left leg DVT. A high index of suspicion with early recognition is crucial to allow for appropriate and timely management. Endovascular thrombectomy and stenting followed by long term dual-anticoagulation, is the safest and most effective treatment to reduce complications.