Residual aneurysm behavior is associated with aortic outcomes after fenestrated and branched endovascular aortic repair.

OBJECTIVE

Aneurysm behavior after fenestrated and branched endovascular aortic repair (F/B-EVAR) is a marker of treatment success and has been linked with long-term survival. This study aimed to characterize longitudinal changes in residual aneurysm sac behavior after F/B-EVAR and relate these changes to aortic outcomes.

METHODS

We retrospectively analyzed F/B-EVARs performed in 10 sponsor-investigator investigational device exemption trials (2005-2024). Serial imaging after repair was evaluated for changes in residual aneurysm sac behavior. Changes in sac behavior over time were investigated with a multistate time-to-event survival model, and the time-dependent effect of sac behavior on outcomes was analyzed with a competing risks model for aortic events and nonaortic death.

RESULTS

A total of 1932 patients met the study criteria; 1223 patients (63%) were treated for thoracoabdominal aneurysm with a median preoperative maximum aortic diameter of 61 mm (interquartile range [IQR], 57-67 mm). The median follow-up was 3.5 years (IQR, 2.3-4.6 years) with 3 surveillance imaging studies (IQR, 2-5 studies) available per patient. Endoleak occurred in 1043 patients (54%) and 343 (18%) underwent reintervention. At 1 year, the predicted probabilities of sac states were: 32% for regression (95% confidence interval [CI], 25-40), 42% stability (95% CI, 35-49), expansion 6% expansion (95% CI, 4-7), and 7% death (95% CI, 6-9); the probability of the aneurysm state not yet observed was 14% (95% CI, 10-20). The presence and absence of endoleak at any time in follow-up were associated with the risks of transition to a state of sac expansion (hazard ratio [HR], 1.3; 95% CI, 1.1-1.6; log-rank P = .003) or regression (HR, 2.1; 95% CI, 1.6-2.9; log-rank P < .0001), respectively. Aortic events, including rupture, dissection, and death, occurred in 78 patients (4%). Sac expansion demonstrated at any time after F/B-EVAR was associated with the cause-specific hazards of an aortic event (HR, 3.2; 95% CI, 1.6-6.4; log-rank P = .009), as well as nonaortic death (HR, 1.3; 95% CI, 1-1.6; log-rank P = .02). The hazard of an aortic event did not differ between states of stability and regression, but the presence of an endoleak significantly modified the hazard of aortic event with sac stability (HR, 2.2; 95% CI, 1.1-4.6; log-rank P = .04).

CONCLUSIONS

Residual aneurysm sac behavior after F/B-EVAR is dynamic and influenced by the presence of an endoleak. Sac expansion, even when occurring later in follow-up, was associated with increased hazards of both aortic events and nonaortic death. These findings underscore the importance of diligent surveillance and timely intervention for endoleaks after F/B-EVAR.