Editor's Choice - Peri-operative Mortality and Morbidity of Complex Abdominal Aortic Aneurysm Repair in Switzerland: A Swissvasc Report.

Objective: Complex abdominal aortic aneurysms (cAAA) pose a clinical challenge. The aim of this study was to assess the 30 day mortality and morbidity rates for open aneurysm repair (OAR) and fenestrated or branched endovascular aortic repair (F/B-EVAR), and the effect of hospital volume in patients with asymptomatic cAAA in Switzerland.

Methods: Retrospective, cohort study using data from Switzerland's national registry for vascular surgery, Swissvasc, including patients treated from 1 January 2019 to 31 December 2022. All patients with asymptomatic, true, non-infected cAAA were identified. The primary outcome was 30 day mortality and morbidity rates reported using the Clavien-Dindo classification. Outcomes were compared between OAR and F/B-EVAR after propensity score weighting.

Results: Of the 461 patients identified, 333 underwent OAR and 128 underwent F/B-EVAR for cAAA. At 30 days, the overall mortality rate was 3.3% after OAR and 3.1% after F/B-EVAR (p = .76). Propensity score weighted analysis indicated similar morbidity rates for both approaches: F/B-EVAR (OR 0.69, 95% CI 0.45 - 1.05, p = .055); intestinal ischaemia (1.8% after OAR, 3.1% after F/B-EVAR, p = .47) and renal failure requiring dialysis (1.5% after OAR, 5.5% after F/B-EVAR, p = .024) were associated with highest morbidity and mortality rates. Treatment specific complications with high morbidity were abdominal compartment syndrome and lower limb compartment syndrome following F/B-EVAR. Overall treatment volume was low for most of the hospitals treating cAAA in Switzerland; outliers with increased mortality rates were identified among low volume hospitals.

Conclusion: Comparable 30 day mortality and morbidity rates were found between OAR and F/B-EVAR for cAAA in Switzerland; lack of centralisation was also highlighted. Organ specific complications driving death were renal failure, intestinal ischaemia, and limb ischaemia, specifically after F/B-EVAR. Treatment in specialised high volume centres, alongside efforts to reduce peri-procedural kidney injury and mesenteric ischaemia, offers potential to lower morbidity and mortality rates in elective cAAA treatment.