Factors Influencing Sex Specific Outcomes after Complex Endovascular Aortic Aneurysm Repair: Insights from a National...

The association between female sex and death after aortic aneurysm repair has been widely identified after both elective and emergency aortic surgery. Increasing evidence exists that this is also valid after complex endovascular aortic repair (EVAR). Additionally, an increase in annual hospital volume has been shown to improve results and reduce the mortality rate after complex endovascular aorticrepair (cEVAR). The aim of this study was to evaluate the nationwide peri-operative outcomes of patients who underwent cEVAR within a mandatory quality registry, to assess the effect of sex differences on outcomes and the influence of annual hospital volume on these differences.

All patients prospectively registered in the Dutch Surgical Aneurysm Audit who underwent cEVAR between January 2016 and January 2022 were included. The primary outcome was peri-operative death. Secondary outcomes were peri-operative complications including length of stay and the association between female sex and both these outcomes. Furthermore, the effect on mortality differences and hospital volume was assessed to evaluate the influence of hospital volume on mortality among women after cEVAR.

A total of 1 150 patients were included: 857 patients undergoing fenestrated EVAR (74.5%) and 293 patients undergoing branched EVAR (25.5%); 925 were male (80.4%) and 225 were female (19.6%). The overall peri-operative mortality rate was 4.7% (n = 54); 3.8% (n = 35) for men vs. 8.4% (n = 19) for women (odds ratio 2.40, 95% confidence interval 1.25 - 4.51; p = .007). Post-operative complications occurred more frequently in women 40.0% (n = 90) compared with men 30.3% (n = 280) (p = .006). Length of hospital stay was significantly increased in women compared with men (four vs. five days, respectively; p < .001). The mortality rate among women after cEVAR in low volume hospitals (fewer than ten annual procedures) was significantly higher than high volume centres; 14.6% vs. 7.1% (odds ratio 2.13, 95% confidence interval 1.12 - 3.99; p = .019). After adjustment for known confounding factors, both sex and hospital volume were significantly associated with mortality in the multivariable analysis. Formal interaction testing between annual hospital volume, female sex, and mortality confirmed the observation (Wald χ² = 6.40; p = .041) that low volume was significantly associated with mortality, especially in women.

Real world mandatory quality registry data provide a robust overview on sex specific differences and peri-operative outcomes following complex EVAR in The Netherlands. Women are at risk of impaired survival and worse peri-operative outcomes compared with men after cEVAR. Furthermore, this study identified a protective effect of hospital volume on this association up to 20 cases per year. Patients should be treated in high volume centres to improve survival and to mitigate the sex disadvantage after cEVAR.