Endovenous Intervention of May-Thurner Syndrome with Thrombus beyond Iliac Vein Stenosis

PURPOSE: With the increase in the incidence of venous thrombosis, interest in May-Thurner syndrome (MTS) accompanying iliac vein compression has increased. Some patients with MTS have inferior vena cava thrombosis or thrombosis beyond iliac vein stenosis (TBIVS). This study aimed to identify the characteristics of MTS with TBIVS including pulmonary embolism (PE) and post-thrombotic syndrome (PTS) compared to those of MTS without TBIVS. MATERIALS AND METHODS: Thirty-five patients with deep vein thrombosis associated with MTS were treated between March 2012 and February 2016. Demographic data, medical history, computed tomography findings (iliac vein size of stenosis and stenotic ratio compared with the other side), and clinical outcomes (preoperative PE and PTS) were retrospectively collected and reviewed by dividing into groups with or without TBIVS. RESULTS: Eight of the 35 patients with MTS had TBIVS. The group with TBIVS had a statistically significantly greater iliac vein size (P<0.001) and ratio (P=0.001). PE was more prevalent in the group with TBIVS (63% vs. 15%, P=0.007). However, no statistically significant intergroup difference in PTS prevalence was found. CONCLUSION: The presence of mild iliac vein stenosis in MTS can be used to predict TBIVS and the requirement for more attention to PE.