IFT07 - Clinical Impact and Determinants of Fenestration-to-Target Vessel Misalignment in Fenestrated Endovascular Aortic Repair

Objectives: To investigate the clinical impact and determinants of fenestration-to-target vessel misalignment in fenestrated endovascular aortic repair (FEVAR), using a computed tomography angiogram (CTA) post-implantation analysis.

Methods: We retrospectively reviewed single-center data on consecutive patients undergoing FEVAR (2014-2021). Two components of fenestration misalignment were measured on the first post-operative CTA (performed within 30 days): the “horizontal misalignment” (defined as the angle between the fenestration and the target vessel ostium on CTA axial cuts) (Figure 1) and the “vertical misalignment” (defined as the vertical distance along the aortic centerline between the mid-point of the fenestration and the mid-point of the target vessel at its origin). The primary endpoint was freedom from target vessel instability, defined as any target vessel-related complication leading to aneurysm rupture, death, occlusion, component separation, or reintervention. A penalized splines function was used to determine the clinical impact of misalignment on target vessel instability. Preoperative clinical and anatomical characteristics, including aneurysm diameter, aortic angulation, iliac access tortuosity index, and post-implantation bridging length (the gap distance between the endograft fenestration and the origin of the target vessel) were evaluated for their association with clinically significant misalignment, using univariate and multivariate logistic regression models.

Results: There were 50 patients (juxta/pararenal: n=39, 78%; thoracoabdominal: n=11, 22%), with 155 target arteries incorporated through a bridging stent. Mean horizontal misalignment was 10±11° and mean vertical misalignment was 1±1 mm. Freedom from target vessel instability was 87% (95%CI 81-95) at 42 months. The cutoff analysis identified an horizontal misalignment >15° as significantly associated with target vessel instability (HR 5.9, 95%CI 1.63-21.32; P=.006) (Figure 2), while vertical misalignment was not significantly associated (HR 1.21, 95%CI 0.79-1.86; P=.376). By multivariate analysis, pararenal aortic angulation (HR 1.01, 95%CI 1.00-1.01; P=.044), iliac access tortuosity index (HR 1.55, 95%CI 1.01-2.61; P=.047), bridging length >5 mm (HR 1.07, 95%CI 1.02-1.11; P=.003), and operator’s learning curve (HR 0.96, 95%CI 0.94-0.99; P=.043) were determinants of a clinically significant horizontal misalignment >15°.

Conclusions: Horizontal misalignment >15° is associated with worsened target vessels outcomes. This may occur as a result of excessive iliac access tortuosity, high pararenal aortic angulation, and bridging distance >5 mm. Operator’s experience as well as evolution of endograft’s materials and profile may be useful to improve fenestrations’ alignment. Bridging stent reinforcement or closer follow-up may be considered in case of post-implantation horizontal misalignment >15°.