Fenestrated Aortic Aneurysm Repair in Patients Treated Inside Versus Outside of Instructions for Use

Abstract

Objectives: The aim of this study was to compare outcomes of patients treated with the Cook Zenith Fenestrated (ZFEN) device for juxtarenal aortic aneurysms inside versus outside the IFU. Methods: We retrospectively reviewed our institutional ZFEN database for cases performed between 2012 and 2018, with analysis performed in 2020 in order to report midterm outcomes. The cohort was stratified based on treatment inside (IFU group) and outside (non-IFU group) the IFU for criteria involving the proximal neck: neck length 4 to 14 mm, neck diameter 19 to 31 mm, and neck angulation ≤45°. Patients with thoracoabdominal aneurysms or concurrent chimney grafting were excluded. The primary outcomes in question were mortality, type 1a endoleak, and reintervention. Univariate and multivariate analyses were performed to determine associations between adherence to IFU criteria and outcomes. Results: We identified 100 consecutive patients (19% female, mean age 73.6 years) for inclusion in this analysis. Mean follow-up was 21.6 months. Fifty-four patients (54%) were treated outside the IFU because of inadequate neck length (n=48), enlarged neck diameter (n=10), and/or excessive angulation (n=16). Eighteen patients were outside IFU for two criteria, and one patient was outside IFU for all three. Non-IFU patients were exposed to higher radiation doses (3652 vs 5445 mGy, p=0.008) and contrast volume (76 vs 95 mL, p=0.004). No difference was noted between IFU and non-IFU groups for 30-day mortality (0% vs 3.7%, p=0.18), or type 1a endoleak (0% vs 1.9%, p=0.41). Reintervention was also similar between cohorts (13% vs 27.8%, p=0.13). Being outside IFU for neck diameter or length was each borderline significant for higher reintervention on univariate analysis (p=0.05), but this was not significant on multivariate Cox proportional hazard modeling (HR 1.82 [0.53–6.25]; 2.03 [0.68–7.89]), respectively. No individual IFU deviations were associated with the primary outcomes on multivariate analysis, nor being outside IFU for multiple criteria. Conclusions: Patients with juxtarenal aortic aneurysms may be treated with the ZFEN device with moderate deviations from the IFU. While no differences were seen in mortality or proximal endoleak, larger studies are needed to examine the potential association between IFU nonadherence and reinterventions and close follow-up is warranted for all patients undergoing such repair.