Outcomes Following Iliac Vein Stenting for Non-Thrombotic Iliac Vein Lesions—A Narrative Review Based on Large Sample Studies

<i>Objective:</i> May-Thurner syndrome typically refers to symptoms and signs arising from the compression of the left common iliac vein by the right common iliac artery. However, such clinical manifestations can occur in the setting of compression of the right common iliac vein and/or either external iliac vein. Given this scenario, the more appropriate term for the condition would be non-thrombotic iliac vein lesion(s) [NIVL]. The goal of this review of large sample size studies is to evaluate outcomes following stenting for chronic iliofemoral venous obstruction (CIVO) due to NIVL, including clinical, quality-of-life, and stent-related outcomes. Additionally, where evidence gaps or controversies exist, expert opinion has been offered for guidance. <i>Methods:</i> A review of the literature was undertaken to determine the role of stenting for NIVL. Appropriate search terms were used to search PubMed, Cochrane Central Register of Controlled Trials, and EMBASE. Studies were only included if they had a sample size of at least 100 limbs that underwent stenting for NIVL and had at least 12 months of follow-up. Additionally, every study needed to have at least one metric of objective clinical evaluation [Venous clinical severity score (VCSS)] and/or a quality-of-life (QoL) measure (generic or venous disease-specific). <i>Results:</i> A total of six studies met the eligibility criteria and included 1404 limbs that underwent stenting for NIVL. All except three studies had a combination of PTS and NIVL limbs, with all six studies having at least 100 limbs that underwent stenting for NIVL. Follow-up varied from 12 to 50 months post-stenting. Improvements in VCSS and quality-of-life measures were noted post-stenting. Additional outcome measures, like grade of swelling or visual analog scale pain score, when utilized, also demonstrated improvement. Recurrence-free ulcer healing rates of 63% to 82% were observed. Good long-term stent primary stent patencies (74-98%) were also reported, irrespective of stent type. <i>Conclusions:</i> This review notes that good outcomes can be expected following stenting for CIVO due to NIVL. Gaps, however, exist with regard to patient selection, peri/post-procedural antithrombotic strategies, and long-term follow-up in this context. A CEAP clinical class-based algorithm is provided to help with patient selection in addition to guidance on antithrombotic therapy and follow-up. Further study of these areas is merited.