ABSTRACT
Objective@#May-Thurner syndrome (MTS) is a condition, in which the left common iliac vein is compressed by the right common iliac artery and spine, resulting in an increased risk of deep vein thrombosis (DVT). This study examined the clinical features of MTS and relationship of MTS with a pulmonary embolism (PE) in acute DVT patients. @*Methods@#This study was a retrospective observational study using the electronic medical records of patients with acute DVT in 2018. Acute DVT patients were divided into the MTS group (n=18, 23.1%) and non-MTS group (n=60, 76.9%) according to the presence of MTS. The following items were compared: demographic data, risk factors of DVT, vital signs, laboratory results, involvement site of vein, incidence of PE, and severity of PE. @*Results@#The presence of risk factors was similar in the two groups. All MTS patients had DVT in the left lower extremity. The ilio-femoral DVT (21.7% vs. 77.8%, P<0.001) and mixed DVT (both ilio-femoral and femoro-popliteal, 10.0% vs. 44.4%; P=0.002) were observed more frequently in the MTS group. The incidence of PE was higher in the non-MTS group (65.0%) than in the MTS group (33.3%) (P=0.017). On the other hand, the severity of PE assessed with main pulmonary artery involvement or hemodynamic instability, and right ventricular dysfunction did not show a significant difference between the two groups. @*Conclusion@#DVT could develop with the presence of risk factors in MTS patients. DVT patients with MTS might reduce the risk of developing PE compared to those without MTS, but the severity of PE was similar in the two groups.