May-Thurner Syndrome: A Rare and Under-Appreciated Cause of Venous Thrombosis in a 18-Year-Old Healthy Female

Abstract

May-Thurner syndrome (MTS) is a rarely diagnosed vascular abnormality that typically presents in young adults. The anomaly arises from compression of the left common iliac vein between the right iliac artery anteriorly and the lumbar vertebral body posteriorly, resulting in lower extremity venous outflow obstruction and recurrent deep vein thromboses (DVTs). We report the case of a 24-year-old female with a long history of recurrent DVTs and pulmonary emboli (PE) despite full anticoagulation. A computed tomography (CT) scan revealed findings consistent with MTS, and a left common iliac vein stent was placed. However, the patient continued to have DVTs while trialing several anticoagulation therapies, including rivaroxaban, enoxaparin, and warfarin. Eventually, the patient developed arterial thrombi resulting in critical limb ischemia, necessitating a right below knee amputation (BKA). One month status-post BKA, the patient was admitted for severe BKA stump pain secondary to infection and necrosis. She underwent BKA revision, but continued to experience pain post-operatively and was found to have new right common iliac artery, external iliac artery, and common femoral artery thrombosis in the setting of continued inpatient anticoagulation therapy with enoxaparin and aspirin. The patient returned to the operating room for emergent Fogarty thrombectomy, however, this was complicated by rupture of the balloon catheter secondary to migration of the left common iliac vein stent into the right common iliac artery lumen. A stent was placed in the right common iliac artery to shift the rogue vein stent, but the patient continued to have poor distal circulation of the BKA stump and eventually underwent an above knee amputation. Dual anti-platelet therapy (DAPT) with aspirin and clopidogrel in combination with enoxaparin were used to prevent in-stent thrombosis and future formation of arterial and venous thrombi. After the initiation of DAPT and enoxaparin, her clinical course was free of any further thromboembolic events. Clinicians should consider MTS in the differential diagnosis of younger adults presenting with recurrent DVTs or other unprovoked thromboembolic events. A two-pronged strategy of DAPT and anticoagulation was employed for successful prevention of thrombotic events.

May-Thurner Syndrome: An Underdiagnosed Entity

“…5 Overall, MTS is estimated to be the cause of 2% to 5% of all deep vein thromboses, and multiple autopsy studies in randomized patients have revealed a prevalence of MTS between 14% and 32%. 6,7 A retrospective study showed 24% of patients who underwent computed tomography of the abdomen and pelvis without suspicion of vascular pathology had a high degree of compression in the iliac vein, which corresponds to the typical image that is presented in the MTS. 6 Other radiologic studies, specifically targeting patients with left lower limb thrombosis, reported an incidence of MTS of 22% to 76%.…”

“…6 Other radiologic studies, specifically targeting patients with left lower limb thrombosis, reported an incidence of MTS of 22% to 76%. More recent epidemiologic studies showed that 72% of MTS cases are diagnosed between the ages of 25 and 50, which is far from the age of the individuals included in the manuscript by Cohen et al 1,7,8 Most patients have no symptoms during their lifetime; therefore, some authors have proposed using the term "May-Thurner anatomy" in patients without hemodynamic significance and reserving the term "May-Thurner syndrome" for cases with the compromised venous flow and clinical symptoms. 6 Approximately 77% of patients with MTS develop iliofemoral deep vein thrombosis and 23% develop venous claudication, resulting in a major disease with significant costs to health systems.…”

“…The decrease in the venous lumen may exist in healthy individuals, which is why clinical correlation is important to identify patients who benefit from clinical or surgical medical treatment 5. Overall, MTS is estimated to be the cause of 2% to 5% of all deep vein thromboses, and multiple autopsy studies in randomized patients have revealed a prevalence of MTS between 14% and 32% 6,7. A retrospective study showed that 24% of patients who underwent computed tomography of the abdomen and pelvis without suspicion of vascular pathology had a high degree of compression in the iliac vein, which corresponds to the typical image that is presented in the MTS 6.…”