A stable aneurysm sac after endovascular aneurysm repair as a predictor for mortality: An in-depth analysis

The aim of the present study was to compare the long-term survival of patients with a stable aneurysm sac vs those with aneurysm sac regression after endovascular aneurysm repair (EVAR) and to identify the independent risk factors for aneurysm sac regression and mortality after EVAR.

We reviewed all the patients who had undergone EVAR from 2005 to 2018 with computed tomography angiography available at 1 year of follow-up. Aneurysm sac regression was defined as a diameter decrease of >10%. We used multivariable regression to identify the independent risk factors for sac regression. Kaplan-Meier analysis and Cox regression were performed to test the differences in 5-year mortality between a stable sac diameter and sac regression.

The inclusion criteria were met by 325 patients, with 185 in the sac regression group and 140 in the stable sac group. Multivariable logistic regression analysis showed that treatment of a ruptured aneurysm was an independent risk factor for aneurysm sac regression (hazard ratio [HR], 0.26; 95% confidence interval [CI], 0.07-0.96). Age (HR, 1.05; 95% CI, 1.01-1.09), ischemic heart disease (HR, 1.94; 95% CI, 1.13-3.31), neck thrombus (HR, 2.72; 95% CI, 1.07-6.95), and a type II endoleak (HR, 19.21; 95% CI, 7.32-50.40) were independent risk factors for a stable aneurysm sac diameter. Multivariable Cox regression showed a significantly increased risk of mortality for patients with a stable aneurysm sac after EVAR (odds ratio, 2.25; 95% CI, 1.36-3.72). No significant differences were found in cause of death between the two groups.

A stable aneurysm sac after EVAR was associated with increased mortality. Age, ischemic heart disease, neck thrombus, and a type II endoleak were independent risk factors for a stable aneurysm sac. However, a well-founded explanation for this finding is still lacking. Future research should focus on aggressive treatment of type II endoleaks and inflammatory processes as potential pathophysiologic mechanisms.