Caseload or endovascular aortic repair is not associated with a change in 90-day mortality after surgery for ruptured abdominal aortic aneurysms in Sweden

BACKGROUND: Reports on mortality rates after ruptured abdominal aortic aneurysm (RAAA) vary. We investigated whether institutional caseload volume of abdominal aortic aneurysm (AAA) or institutional proportion of endovascular aortic repair (EVAR) for RAAA are associated with decreased 90-day mortality of RAAA in Sweden. METHODS: Retrospective, observational, nationwide, five-year, cohort study of 1040 RAAAs from Swedvasc, a prospective vascular registry including all vascular units in Sweden. Patient age, sex, heart disease, previous cardiac insufficiency, pulmonary disease, kidney disease, patient frailty, preoperative hemodynamic instability, and loss of consciousness were retrieved from different data sources and modelled versus 90-day mortality with logistic regression. Supplementary variables helped for imputation of missing values. Each patient was assigned a Hospital Caseload Value (HCV) the annual caseload volume of (intact and ruptured) AAAs at the hospital performing the operation and a Hospital EVAR proportion Value (HEV) the proportion of EVAR at the hospital performing the operation when treating RAAA. Further, institutional 90-day mortality was regressed on institutional caseload volume and proportion of EVAR for RAAA with logistic regression. RESULTS: Ninety-day mortality was 30.4 percent. Neither HCV nor HEV were associated with postoperative mortality for individual patients (HCV odds ratio (OR) 1.10, P value=0.28; HEV OR 1.04, P value=0.46) or at the institutional level (caseload volume OR=1.06, P=0.19, and proportion of EVAR use OR=1.01, P=0.46). CONCLUSIONS: Caseload of AAA or EVAR for RAAA were not associated with a change in postoperative 90-day mortality in Sweden.