Renal Artery Aneurysms in the Inpatient Setting

Background: The risk of rupture of renal artery aneurysms (RAAs) remains undefined. A recent paper from the Vascular Low-Frequency Disease Consortium (VLFDC) identified only 3 ruptures in 760 patients. However, over 80% of patients in the VLFDC study were treated at large academic centers, which may not reflect the pattern of care of RAAs nationwide. Thus, the purpose of this study was to evaluate the pattern of nonelective versus elective surgery requiring inpatient admission for RAAs, including nephrectomies, and their outcomes using a national database. Methods: The National Inpatient Sample (NIS) database from 2012 to 2018 was utilized. Patients with a primary diagnosis of RAAs were identified using ICD-9 and ICD-10 codes. Ruptured RAAs (rRAAs) were identified utilizing surrogate ICD codes. The primary outcome variables for this study were proportion of RAAs requiring non-elective surgery and in-hospital mortality. Results: A total of 590 inpatient admissions for RAA were identified with 554 procedures at 467 hospitals across the country. Of the 590 inpatient admissions, 380 (64.4%) admissions were deemed nonelective. There was an increasing proportion of nonelective admissions over the study period. The overall rate of nephrectomies was 7.1% (n = 42). In-hospital mortality rate for the cohort was 1.4% (n = 8) with no differences in in-hospital mortality in the elective versus nonelective setting (1.0% vs. 1.6%; P = 0.718). In the nonelective setting, patients requiring a nephrectomy (n = 23) had significantly higher rates of in-hospital mortality compared those not requiring a nephrectomy (8.7% vs. 1.1%, P = 0.045). rRAA (n = 50) patients had significantly higher in-hospital mortality compared to the remainder of the cohort (6.0% vs. 0.9%, P = 0.024). rRAA patients were also more likely to undergo a nephrectomy compared to the remainder of the cohort (16.0% vs. 6.3%, P = 0.019). Conclusions: These data demonstrate that treatment of RAAs are primarily done in the nonelective setting with a high proportion of ruptures, which could continue to rise as the threshold for repair has decreased.