Effect of Narrow Paravisceral Aorta on Target Vessel Instability After Fenestrated-Branched Endovascular Aortic Repair

Abstract

The aim of this study was to investigate the effect of narrow paravisceral aorta (NPA) on target vessels instability (TVI) after fenestrated-branched endovascular aortic repair (F-BEVAR). We conducted a single-center retrospective study (2014-2022) on patients treated by F-BEVAR for thoracoabdominal (TAAAs) or pararenal aortic aneurysms (PRAAs). Paravisceral aorta was defined as the aortic segment limited by the diaphragmatic hiatus proximally and the emergence of lower renal artery distally and was considered “narrow” in case of minimum inner diameter <25 mm. Minimum aortic diameter, location, longitudinal extension, angulation, calcification, and thrombus thickness of NPA were evaluated at the preoperative computed tomography angiogram. Endpoints were technical success and freedom TVI (target vessel-related death, occlusion, rupture or reintervention for stenosis, endoleak, or disconnection). Kaplan-Meier estimates and Cox proportional hazards were used for analysis. Three hundred ninety-five incorporated target arteries were analyzed (110 patients; 50 TAAAs and 60 PRAAs), 214 fenestrations (54%), 102 outer branches (26%), and 79 inner branches (20%). NPA was present in 59 patients (54%), accounting for 202 target vessels (136 fenestrations, 44 inner branches, and 22 outer branches); the non-NPA group had 193 target vessels (78 fenestrations, 35 inner branches, and 80 outer branches). Overall technical success was 99% (NPA: 99%, Non-NPA: 99%; P = .879). Overall freedom from TVI at 4 years was 91% ± 5% (NPA: 90% ± 6%, non-NPA: 93% ± 6%; P = .752). After stratification by endograft design, NPA was not associated with TVI (fenestrations: hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.04-3.47; P = .442; inner branches: HR, 2.25; 95% CI, 0.47-16.25; P = .343; outer branches: HR, 1.09; 95% CI, 0.27-4.17; P = .891). The association of use of outer branches in NPA plus location at the level of the aortic zone 6 (from the origin of the celiac artery to the superior mesenteric artery), longitudinal extension >25 mm, or aortic wall moderate/severe calcifications, was cause of worsened freedom from TVI (P = .043; P = .031; and P = .045; respectively). Thrombus thickness (HR, 1.03; 95% CI, 0.93-1.13; P = .536) and angulation (HR, 1.02; 95% CI, 0.94-1.18; P = .602) of NPA were not significantly associated. NPA <20 mm was a negative predictor for bridging stents patency (HR, 1.12; 95% CI, 1.09-6.99; P = .028) with the use of fenestrations. FEVAR and BEVAR are both feasible in cases of NPA, and overall provide satisfactory target vessels durability. The use of outer branches should be avoided in cases with inner aortic diameter <25 mm at the level of the aortic zone 6, with longitudinal extension >25 mm, or moderate/severe NPA calcifications. In FEVAR, bridging stent patency may be negatively influenced by NPA<20 mm.