Comparative Effectiveness of Two Novel Anti-Migration Strategies in Fully Covered Self-Expandable Metal Stents for Biliary Strictures: A Multicenter Propensity-Matched Study

Fully covered self-expandable metal stents (FCSEMS) are used for benign and malignant biliary strictures, though stent migration and occlusion remain important limitations. A novel FCSEMS with an anchoring bump and enlarged distal flare (FCSEMS-AB) was recently introduced as an alternative anti-migration design to FCSEMS with anchoring fins (FCSEMS-AF). We compared migration and occlusion rates between these stent types.

We performed a multicenter retrospective cohort study of patients undergoing FCSEMS placement at three tertiary centers. Patients received either FCSEMS-AF (Viabil) or FCSEMS-AB (WallFlex Plus). Propensity score matching was performed to balance baseline characteristics. Logistic regression and Cox proportional hazards models were used to evaluate outcomes.

Among 228 patients, 143 received FCSEMS-AF and 85 received FCSEMS-AB. After propensity matching, 64 matched pairs were analyzed. FCSEMS-AB was associated with significantly higher odds of stent migration compared with FCSEMS-AF in both unadjusted (OR 5.00, 95% CI 1.57-15.94, p=0.007) and adjusted analyses (aOR 5.25, 95% CI 1.58-17.49, p=0.007). Time-to-event analyses similarly demonstrated increased migration risk with FCSEMS-AB (adjusted HR 6.26, 95% CI 2.01-19.55, p=0.002). FCSEMS-AB was associated with lower odds of stent occlusion in adjusted logistic regression (aOR 0.27, 95% CI 0.10-0.78, p=0.015), though this association was not statistically significant in time-to-event analysis. Mortality did not differ between groups.

FCSEMS-AB was associated with significantly higher migration risk compared with FCSEMS-AF, while demonstrating lower rates of stent occlusion. These findings highlight a trade-off between migration resistance and stent patency that may guide individualized stent selection.