Title
Multimodal Approach to the Treatment of Complex Iliocaval Thromboses Presenting as Bilateral Pulmonary Emboli in a Patient with May-Thurner Syndrome Introduction
May-Thurner syndrome (MTS) results from compression of the iliocaval venous system by the arterial system against a vertebral body. This anatomic variant is often asymptomatic, but it becomes clinically significant when it causes venous thrombosis. This is a case of iliocaval thromboses resulting in bilateral pulmonary emboli in a young patient with May-Thurner syndrome.
Clinical Case
A 21 year old morbidly obese female with chronic NuvaRing use and family history of homocysteinemia presented with left lower extremity pain and dyspnea. Physical examination revealed hypotension, tachypnea, tachycardia, and left lower extremity swelling and discoloration consistent with phlegmasia cerulea dolens. Chest CT angiography revealed bilateral pulmonary emboli with right ventricular strain (RV:LV ratio 1.37:1). Venous doppler revealed extensive acute deep vein thromboses in the left lower extremity. Right heart catheterization revealed near-normal pressures with normal cardiac output and index. Pulmonary angiogram revealed segmental filling defect in the right middle pulmonary artery with oligemia in the right middle and right lower lobes. Because the patient was dyspneic, the decision was made to perform EKOS catheter-directed thrombolysis of the right pulmonary artery. The patient's lower extremity swelling persisted and prevented her from bearing weight, so ascending venography was performed, revealing extensive thrombus from the left popliteal vein to the distal inferior vena cava (IVC). A Cook IVC filter was placed to prevent embolization. The Inari FlowTriever Retrieval/Aspiration System was placed into the left popliteal vein, and thrombectomy was performed twice, with extensive thrombus removal. Venography then revealed persistent thrombus, some of which had embolized but was successfully caught by the IVC filter. An EKOS catheter with tPA infusion was then placed from the distal IVC past the IVC filter to the left popliteal vein. Repeat venography on the following day revealed significantly improved flow with residual thrombus in the common femoral vein, which was removed using the Indigo CAT8 device. Intravascular ultrasound (IVUS) confirmed compression at the ostium of the left common femoral vein (area 31.6 mm
2), consistent with May-Thurner syndrome. An 18 x 90 mm wall stent was placed, improved the area to 113 mm
2. The patient was started on clopidogrel and warfarin. Since hospital discharge, she had significant improvement in her left lower extremity swelling and was ambulating without difficulty. The IVC filter was removed 4 months later without any complications. Repeat venography confirmed complete resolution of the thrombus.
Discussion
May-Thurner Syndrome (MTS) accounts for 5% of symptomatic lower extremity DVTs and should therefore be considered as a differential diagnosis when a patient presents with acute DVT. Ascending venography with intravascular ultrasound is the gold standard for definitive diagnosis and treatment of MTS. In this case, due to the complexity of the thromboses, treatment required the use of multiple modalities including IVC filter placement, EKOS catheter-directed thrombolysis, and mechanical thrombectomy using the Inari FlowTriever and Indigo CAT8 device.