Incidence and risk factors for interval aortic events during staged fenestrated-branched endovascular aortic repair

Objective: Staged endovascular repair of complex aortic aneurysms with first-stage thoracic endovascular aortic repair may decrease the risk of spinal cord ischemia (SCI) associated with fenestrated-branched endovascular aortic repair (FB-EVAR) of thoracoabdominal aortic aneurysms or optimize the proximal landing zone in the cases requiring total aortic arch repair. However, a limitation of multistaged procedures is the risk of interval aortic events (IAEs) including mortality from a ruptured aneurysm. We aim to identify the incidence of and risk factors associated with IAEs during staged FB-EVAR. Methods: This was a single-center, retrospective review of patients who underwent planned staged FB-EVAR from 2013 to 2021. Clinical and procedural details were reviewed. End points were the incidence of and risk factors associated with IAEs (defined as rupture, symptoms, and unexplained death) and outcomes in patients with or without IAEs. Results: Of 591 planned FB-EVAR patients, 142 underwent first-stage repairs. Twenty-two did not have a planned second stage because of frailty, preference, severe comorbidities, or complications after the first stage and were excluded. The remaining 120 patients (mean age: 73 ± 6 years, 51% female) were planned for second-stage completion FB-EVAR and comprised our cohort. The incidence of IAEs was 13% (16 of 120). This included confirmed rupture in 6 patients, possible rupture in 4, symptomatic presentation in 4, and early unexplained interval death with possible rupture in 2. The median time to IAEs was 17 days (range: 2-101 days), and the median time to uncomplicated completion repairs was 82 days (interquartile range: 30-147 days). Age, sex, and comorbidities were similar between the groups. There were no differences in familial aortic disease, genetically triggered aneurysms, aneurysm extent, or presence of chronic dissection. Patients with IAEs had significantly larger aneurysm diameters than those without IAEs (76.6 vs 66.5 mm, P ≤ .001). This difference persisted with indexing for body surface area (aortic size index: 3.9 vs 3.5 cm/m², P = .04) and height (aortic height index: 4.5 vs 3.9 cm/m, P ≤ .001). IAE mortality was 69% (11 of 16) compared with no perioperative deaths for those with uncomplicated completion repairs. Conclusions: The incidence of IAEs was 13% in patients planned for staged FB-EVAR. This represented a notable morbidity, including rupture, which must be balanced with SCI and landing zone optimization when planning repair. Larger aneurysms, especially when adjusted for body surface area, are associated with IAEs. Minimizing time between stages vs single-stage repairs for larger (>7 cm) complex aortic aneurysms in patients with reasonable SCI risk should be considered when planning repair.