03:27 PM Abstract No. 96 Prevalence of May-Thurner variants in patients with symptomatic May-Thurner syndrome

Abstract

May-Thurner syndrome (MTS) is typically characterized by the compression of the left common iliac vein (LCIV) between the right common iliac artery (RCIA) and the fifth vertebra. Various types of May-Thurner variants (MTV) have been sporadically documented in case reports. This study aimed to identify the prevalence of MTV among the subset of symptomatic MTS. Single-center data of 173 consecutive patients presented with symptomatic MTS were reviewed from October 2004 to April 2018. MTS was diagnosed by computed tomographic venography. MTV was defined as (i) compression of the LCIV by other structures than the RCIA or (ii) compression of other pelvic veins than the LCIV. MTV was categorized as (i) LCIV compression group if the LCIV is compressed by other structures than the RCIA and (ii) non-LCIV compression group if the LCIV is not involved. Ten MTV were identified (5.8%), including 5 LCIV compression (category 1) and 5 non-LCIV compression (category 2). Patients’ median age was 76 years (range, 51-94 years), male/female: 1/1, median follow-up was 388 days (range, 12-4694 days). All patients presented with deep vein thrombosis of the corresponding limbs. In category 1, the LCIVs were compressed by the left common iliac artery (LCIA) (n=2), huge myoma (n=1), LCIA aneurysm (n=1) and RCIA aneurysm (n=1). In category 2, the right common iliac veins (RCIVs) were compressed by RCIA (n=4) and L5 osteophyte (n=1). Inferior vena cava filters were inserted in 4 patients. Endovascular management with balloon angioplasty and stent insertion were performed in 6 patients, 3 of each category. One patient underwent endovascular aneurysm repair for RCIA aneurysm. The rest 3 patients received conservative treatment due to advanced age and comorbidities. Follow-up images were available for 6 patients and all of them had patent venous outflow. This study brings attention to the relatively high variant of symptomatic MTS population. Vigilance of different anatomical MTV is essential for correct diagnosis and treatment. Endovascular management is safe and effective and should tailor the lesion anatomy.