Analysis of Target Vessel Instability in Fenestrated Endovascular Repair (f-EVAR) in Thoraco-Abdominal Aortic Pathologies.

Objective: The aim of this study was to evaluate the influence of target vessel anatomy and post-stenting geometry on the outcome of fenestrated endovascular aortic repair (f-EVAR). Methods: A retrospective review of data from a single center was conducted, including all consecutive fenestrated endovascular aortic repairs (f-EVARs) performed between September 2018 and December 2023 for thoraco-abdominal aortic aneurysms (TAAAs) and complex abdominal aortic aneurysms (cAAAs). The analysis focused on the correlation of target vessel instability to target vessel anatomy and geometry after stenting. The primary endpoint was the cumulative incidence of target vessel instability. Secondary endpoints were the 30-day and follow-up re-interventions. Results: A total of 136 patients underwent f-EVAR with 481 stented target vessels. A total of ten target vessel instabilities occurred including three in visceral and seven instabilities in renal vessels. The cumulative incidence of target vessel instability with death as the competing risk was 1.4%, 1.8% and 3.4% at 1, 2 and 3 years, respectively. In renal target vessels (260/481), a diameter ≤ 4 mm (OR 1.21, 95% CI 1.035-1.274, p = 0.009) and an aortic protrusion ≥ 5.75 mm (OR 8.21, 95% CI 3.150-12-23, p = 0.027) was associated with an increased target vessel instability. In visceral target vessels (221/481), instability was significantly associated with a preoperative tortuosity index ≥ 1.25 (HR 15.19, CI 95% 2.50-17.47, p = 0.045) and an oversizing ratio of ≥1.25 (HR 7.739, CI % 4.756-12.878, p = 0.049). Conclusions: f-EVAR showed favorable mid-term results concerning target vessel instability in the current cohort. A diameter of ≤4 mm and an aortic protrusion of ≥5.75 mm in the renal target vessels as well as a preoperative tortuosity index and an oversizing of the bridging stent of ≥1.25 in the visceral target vessels should be avoided.