ABSTRACT
OBJECTIVES: To evaluate the effect of fenestration configuration and fenestration gap on renal artery outcomes during fenestrated-branched endovascular aortic repair (F/BEVAR). METHODS: A retrospective multicenter analysis was performed, including patients with complex aortic aneurysms treated with F/BEVAR that incorporated at least one small fenestration to a renal artery. The renal fenestrations were divided into groups 1 (8x6 mm) and 2 (6x6 mm). Primary patency, target vessel instability (TVI), freedom from secondary interventions (SIs), occurrence of type IIIc endoleak, all related to the renal arteries, were analyzed at 30-day, 1-year, and 5-year landmarks. The fenestration gap (FG) distance was analyzed as a modifier, and clustering was addressed at the patient level. RESULTS: Seven hundred and ninety-six patients were included in this study, 71.7% male, with a mean age of 73.3±8.1 years. The mean follow-up was 30.0±20.6 months. Of the 1474 small renal fenestrations analyzed, 47.6% were 8x6, and 52.4% were 6x6mm. At the 30-day landmark, primary patency (99.9% vs 98.0%, p-value <0.001 for groups 1 and 2, respectively), freedom from TVI (99.6% vs 97.1%, p-value <0.001 for groups 1 and 2, respectively), and freedom from SI (99.8% vs 98.4%, p-value = .022 for groups 1 and 2, respectively) were higher in 8x6 compared to 6x6 fenestrations, and the incidence of AKI was similar across the groups (92.6% vs 92.7%, p-value = .953 for groups 1 and 2 respectively). The primary patency at 1 and 5 years was higher in 8x6 fenestrations (1-year: 98.8% vs 96.9%; 5-year: 97.8% vs 95.7%, for groups 1 and 2, respectively, p values = .010 and 0.021 for 1 and 5 year comparisons, respectively). The freedom from SIs was significantly higher among 6x6 fenestrations at 5 years (93.1% vs 96.4%, for groups 1 and 2, respectively, p value = .007). The groups were equally as likely to experience a type Ic endoleak (1.3 % and 1.6% for 8x6 and 6x6mm fenestrations, respectively, p = .689). The 6x6 fenestrations were associated with higher risk of kidney function deterioration (17.8%) when compared with 8x6 fenestrations (7.6%) at 5 years (p <.001). The risk of type IIIc endoleak was significantly higher among 8x6 fenestrations at 5 years (4.9% and 2% for 8x6 and 6x6 mm fenestrations, respectively, p= .005). A FG ≥5 mm negatively impacted the cumulative 5-year freedom from TVI (group 1: FG ≥5 mm = 0.714, FG <5 mm = 0.857, p<.001; group 2: FG ≥5 mm = 0.761, FG <5 mm = 0.929, p<.001) and the cumulative 5-year freedom from type IIIc endoleak (group 1: FG ≥5 mm = 0.759, FG <5 mm = 0.921, p=.034; group 2: FG ≥5 mm = 0.853, FG <5 mm = 0.979, p<.001) in both groups and the cumulative 5-year patency in group 2 (group 1: FG ≥5 mm = 0.963, FG <5 mm = 0.948, p=.572; group 2: FG ≥5 mm = 0.905, FG <5 mm = 0.938, p=.036). CONCLUSIONS: Fenestration configuration for the renal arteries impacts outcomes. The 8x6 small fenestrations have better patency at 30-days, 1 year, and 5 years, while 6x6 small fenestrations are associated with lower rates of secondary interventions, primarily due to a lower incidence of type IIIc endoleaks. Fenestration gap ≥ 5 mm at the level of the renal arteries significantly impacts the freedom from TVI, freedom from type IIIc endoleak and 5-year patency independently of the fenestration size or vessel diameter.
