Lower extremity woven and nonwoven venous stent morphology and luminal changes.

Objective: Venous stents are a common treatment modality for obstructive venous disease. Venous stents differentiate themselves by either a woven or braided structure, open or closed cell arrangement or based on material composition (elgiloy vs nitinol). Changes in the morphology of venous stents over time may contribute to restenosis or thrombosis. Woven elgiloy stents are prone to proximal and distal edge deformation compared with dedicated venous stents, which offer increased radial force at stent edges. The objective of this study is to describe luminal morphological changes among various venous stents and between woven to nonwoven venous stent configuration, over time.

Methods: A retrospective review at a single institution between January 2014 and June 2021 identified patients treated with venous stents. Patients with iliac and/or femoral venous stents with intraoperative intravascular ultrasound and a postoperative computed tomography scan were included in the study. Cross-sectional diameters measurements were taken at proximal, middle, and distal portions of each stent from intravascular ultrasound examination at the time of initial stenting and compared with the cross-sectional diameter measurements taken from computed tomography imaging at follow-up. A paired t test was used to compare the luminal change with a D'Agostino-Pearson test used for normality.

Results: Fifty-four stents distributed among 38 patients were identified. The mean time to follow-up was 17.5 months. Stents were placed in the common iliac vein (n = 37, 68.5%), external iliac vein (n = 14, 25.9%), and common femoral vein (n = 3, 5.6%). Implanted stents included the Boston Scientific Wallstent (n = 23, 42.6%), Bard Venovo (n = 3, 5.6%), Boston Scientific Vici (n = 23, 42.6%), and Medtronic Abre (n = 5, 9.3%). The mean luminal loss was measured at 2.12 mm proximally (95% confidence interval [CI], 1.64-2.60; P<.001), 1.29 mm at the mid-stent (95% CI, 0.83-1.74, P<.001), and 1.56 mm distally (95% CI, 0.99-2.12; P<.001). There was no significant difference in luminal changes between woven and nonwoven stents at proximal (P = .374), middle (P = .179), and distal (P = .609) stent measurements.

Conclusions: This study reports morphological changes within venous stents and between woven and nonwoven venous stents. Our findings demonstrate that the edge-stent luminal decrease traditionally attributed to woven configurations also occurs with the newer nonwoven stents. Additional factors such as anatomical location, pelvic curvature, and other external forces may be accountable for this change rather than geometrical configuration of the stent.