RESUMO
OBJECTIVE: This single centre, retrospective study (2014 - 2022) on juxta-, pararenal, or thoraco-abdominal aortic aneurysms treated by fenestrated endovascular aortic repair (FEVAR) was conducted to investigate the clinical impact and determinants of fenestration to target vessel misalignment in FEVAR. METHODS: Pre-operative supracoeliac, pararenal, and infrarenal aortic angles were measured on three dimensional computed tomography angiography (CTA) reconstructions. Two components of misalignment were measured on the first post-operative CTA: horizontal misalignment (angle between the fenestration and the target vessel ostium on perpendicular CTA cuts) and vertical misalignment (vertical distance between the fenestration and the target vessel at its origin). Endpoints were freedom from target vessel instability (TVI) and alignment change over time. RESULTS: Of 65 patients treated by FEVAR, 60 (202 target arteries) with juxta-, pararenal (80%), or thoraco-abdominal aortic aneurysm (20%) were included. Mean horizontal misalignment was 9 ± 12° (median 5°; IQR 0 - 16) and mean vertical misalignment was 0.7 ± 1 mm (median 0 mm, IQR 0 - 1). Freedom from TVI was 92% (95% CI 88 - 98) at 36 months. Horizontal misalignment > 15° was significantly associated with TVI (HR 5.19; 95% CI 1.54 - 17.48; p = .008); vertical misalignment did not significantly impact TVI (HR 0.99; 95% CI 0.56 - 1.73; p = .97). By multivariable analysis, pararenal aortic angle (OR 1.01 per increased degree of angulation; 95% CI 1.00 - 1.02; p = .044), bridging distance > 5 mm (OR 1.07; 95% CI 1.02 - 1.11; p = .003), and use of higher profile endografts in tortuous iliac access (OR 7.55; 95% CI 4.55 - 1.11; p = .003) were associated with clinically significant misalignment. Bridging distance > 5 mm (OR 2.00; 95% CI 1.02 - 11.29; p = .044), degree of baseline misalignment (OR 1.04; 95% CI 1.01 - 1.08; p = .036), and persistence of any primary endoleak for > 6 months (OR 5.85; 95% CI 1.23 - 29.1; p = .023) were associated with misalignment increase during follow up. CONCLUSION: Horizontal misalignment > 15° is associated with worsened target vessel outcomes. This may occur as a result of excessive iliac access tortuosity, high pararenal aortic angulation, and bridging distance > 5 mm.
RESUMO
OBJECTIVE: To investigate geometrical determinants of target vessels instability in fenestrated endovascular aneurysm repair (FEVAR), using a computed tomography angiogram postimplantation analysis. METHODS: We retrospectively reviewed single-center data on consecutive patients undergoing FEVAR (2014-2021). The geometrical analysis consisted in the assessment of bridging stent lengths and diameters, stent conformation, and graft misalignment. Bridging stent length was categorized in three components: protrusion length (PL) into the main endograft, bridging length (BL) between the fenestration and the origin of the target vessel, and sealing length (SL) of apposition in the target vessel. The conformation was measured as the flare ratio (the ratio of maximum to minimum bridging stent diameter within the PL). Horizontal misalignment was measured as the angle between the fenestration and the target vessel ostium on computed tomography angiography axial cuts. The primary end point was freedom from target vessel instability; secondary end points were target vessels primary patency and freedom from related endoleaks. Time-dependent outcomes were estimated as Kaplan-Meier curves; Cox proportional hazards were used to identify the predictors of target vessel instability. RESULTS: There were 46 patients (juxta/pararenal: n = 34 [74%]; thoracoabdominal: n = 11 [26%]), with 147 target arteries incorporated through a bridging stent. Freedom from target vessel instability was 87% (95% confidence interval [CI], 80-94) at 42 months. Primary patency was 98% (95% CI, 96-100) and freedom from endoleak was 85% (95% CI, 76-93). PL (hazard ratio [HR], 1.08; 95% CI, 0.22-5.28; P = .923), sealing length (HR, 0.95; 95% CI, 0.87-1.03; P = .238), and flare ratio (HR, 4.66; 95% CI, 0.57-37.7; P = .149) were not associated with target vessel instability. By multivariate analysis, a BL of more than 5 mm (HR, 4.98; 95% CI, 1.13-21.85; P = .033) was significantly associated with instability. Patients with a BL 5 mm or more had a significantly greater degree of horizontal misalignment (21 ± 12° vs 9 ± 13°; P = .011). CONCLUSIONS: An optimal geometrical conformation between the bridging stent and the main endograft at the level of target vessels is warranted to improve the midterm outcomes of FEVAR. A BL of more than 5 mm was associated with a greater risk of target vessel instability, likely as a result of a less accurate endograft alignment. The sizing and planning of FEVAR should be performed to maintain a BL of less than 5 mm.