Bizhi Wei, Caiyun Yuan, Meixiuli Li
EVAR was associated with lower 30-day mortality than OSR in observational studies of ruptured abdominal aortic aneurysm, but the certainty of evidence is very low because treatment allocation was strongly conditioned by baseline physiology and anatomy. The observed association should be interpreted as selection-sensitive, and future comparative studies require detailed physiological and anatomical adjustment.
BACKGROUND: Endovascular aneurysm repair (EVAR) is often associated with lower short-term mortality than open surgical repair (OSR) in observational studies of ruptured abdominal aortic aneurysm (rAAA), but this apparent benefit may reflect hemodynamic stability, anatomical suitability, and emergency treatment allocation. We aimed to reappraise EVAR-OSR comparisons by examining whether mortality estimates are influenced by treatment-selection bias.
METHODS: PubMed, the Cochrane Library, CNKI, and Wanfang Data were searched from inception to May 2026. Comparative rAAA studies reporting extractable mortality data were included. The primary outcome was 30-day mortality. Odds ratios (ORs) with 95% confidence intervals (CIs) were pooled using a random-effects model. Risk of bias was assessed with ROBINS-I, and an exploratory subgroup analysis examined operational treatment-selection categories. The protocol was registered in PROSPERO (CRD420261395354).
RESULTS: Nine studies were included qualitatively, and six studies involving 1,035 patients were included in the primary meta-analysis of 30-day mortality. EVAR was associated with significantly lower 30-day mortality than OSR (OR 0.59, 95% CI 0.44-0.80; P < 0.001; I2 = 0%). A sensitivity analysis additionally including two studies reporting in-hospital or other non-30-day mortality endpoints showed a consistent association (OR 0.63, 95% CI 0.51-0.77; P < 0.001; I2 = 40%). In an exploratory subgroup analysis, five studies were classified as EVAR-favored and one as unclear; no study met the relatively balanced criteria. The subgroup comparison was underpowered and was interpreted descriptively.
CONCLUSIONS: EVAR was associated with lower 30-day mortality than OSR in observational studies of ruptured abdominal aortic aneurysm, but the certainty of evidence is very low because treatment allocation was strongly conditioned by baseline physiology and anatomy. The observed association should be interpreted as selection-sensitive, and future comparative studies require detailed physiological and anatomical adjustment.