Factors influencing the extent of contralateral iliac vein orifice overlap by iliac vein stents.

ObjectiveTo evaluate the factors influencing the extent of contralateral iliac vein orifice coverage by stents extending into the inferior vena cava (IVC) in patients with iliac vein compression syndrome (IVCS).MethodsThis retrospective study included 150 patients with IVCS who underwent unilateral stent placement between September 2018 and October 2020. Diagnosis was based on clinical symptoms, venography showing ≥50% iliac vein narrowing, and exclusion of thrombosis or external compression. Patients received either a braided Wallstent or a laser-cut Smart Control stent. Three-dimensional rotational venography was used in all cases, and intravascular ultrasound (IVUS) was performed in selected patients to guide stent sizing and placement. Postoperative imaging was used to measure stent protrusion into the IVC, iliac vein-IVC angulation, and the percentage of contralateral vein orifice obstruction. Univariate and multivariate regression analyses were conducted to identify factors associated with orifice coverage.ResultsUnivariate analysis showed that stent protrusion length, lateral angulation between the iliac vein and IVC, and stent type were significantly associated with orifice coverage (all p < .001). Age, sex, stent diameter, and anteroposterior angulation were not significant predictors. Multivariate analysis confirmed that stent protrusion length was the strongest predictor (β = 0.595, p < .001), followed by stent type (β = 0.249, p < .001) and lateral angulation (β = -0.242, p = .002), with the model explaining 76.6% of the variation in orifice coverage.ConclusionThe degree of contralateral iliac vein orifice coverage in IVCS is primarily determined by the stent's protrusion length into the IVC, the lateral angulation of the affected iliac vein relative to the IVC, and the mechanical design of the stent. These findings highlight the importance of individualized stent selection and precise deployment to minimize contralateral venous obstruction.