Self-expandable versus balloon-expandable bridging stents in off-the-shelf inner branch repair: Midterm results from the ItaliaN Branched Registry of E-nside EnDograft Registry

Objective: To compare the outcomes of self-expandable (S-EXP) and balloon-expandable (B-EXP) bridging stents used with the E-nside off-the-shelf inner-branch endograft for thoracoabdominal and complex abdominal aortic aneurysm repair within the ItaliaN Branched Registry of E-nside EnDograft registry. Methods: All patients enrolled in the ItaliaN Branched Registry of E-nside EnDograft registry between January 2021 and December 2024 were analyzed. Clinical, anatomical, and procedural data were collected for all target vessels (TVs). The most frequently used S-EXP and B-EXP bridging stents were identified and compared. The primary endpoint was target-vessel instability (TVI), defined as a composite of occlusion, significant stenosis, type IC/IIIB/IIIC endoleak, kinking, disconnection, rupture, or TV-related mortality. Secondary endpoints included technical success and reintervention rates. Results: A total of 581 TVs from 148 patients were analyzed: 423 (72.8%) were bridged with B-EXP and 158 (27.2%) with S-EXP stents. Overall technical success was 99.5%. During a mean follow-up of 22.1 ± 12.3 months, TVI occurred in 40/581 vessels (6.9%), with a lower incidence in the S-EXP group (3.2%) compared with the B-EXP group (8.3%; P = .03). However, this association did not remain statistically significant at multivariable analysis, which identified only renal TVs (odds ratio, 1.87; 95% confidence interval, 1.05-3.82; P = .045) and pre-existing TV stenosis (odds ratio, 1.93; 95% confidence interval, 1.13-4.11; P = .047) as independent predictors of TVI. Conclusions: Inner-branch endovascular repair with the E-nside endograft achieved high technical success and favorable midterm outcomes. A lower crude rate of TVI was observed with S-EXP stents; however, this association did not remain significant after multivariable adjustment. Renal TVs and pre-existing stenosis were identified as the main predictors of instability.