Aneurysm Sac Shrinkage at 1 Year after Fenestrated-branched Endovascular Aortic Repair of Complex Aortic Aneurysms Offers Midterm Survival Advantage

To investigate the impact of early changes in aneurysm sac diameter on patient survival after fenestrated-branched endovascular repair (FB-EVAR) for complex abdominal aortic aneurysms (CAAAs) or thoracoabdominal aortic aneurysms (TAAAs). We reviewed the clinical data of patients enrolled in a prospective nonrandomized study investigating FB-EVAR (2013-2022). Aneurysm sac diameters were measured from computed tomography scans preoperatively and during follow-up. Maximum aortic diameter at 1 year (6-18 months) was compared with the early postoperative measure computed tomography angiography (≤30 days). Patients were classified according to early sac dynamic into sac shrinkage (≥5 mm) or failure to regress (<5 mm or expansion). Primary end point was all-cause survival, and secondary end points were cumulative incidences of aortic-related mortality (ARM), aneurysm rupture and aorta-related secondary intervention. There were 549 patients treated by FB-EVAR. Of these, 463 patients (84%; 71% males; mean age, 74 ± 8 years) had >1-year of follow-up (135 CAAAs, 328 TAAAs). Sac shrinkage at 1 year was observed in 270 patients (58%), sac expansion accounted for 4% of the entire cohort, with no significant difference between patients with CAAAs and TAAAs (P > .05). Patients from both groups had similar cardiovascular risk factors, except for younger age among patients with sac shrinkage (73 ± 8 years vs 75 ± 8 years; P < .001). Median follow-up was 38 months (range, 18-51 months). Survival estimates adjusted for confounders (age, chronic pulmonary disease, heart failure, dialysis, and aneurysm extent) revealed a higher hazard of late mortality in failure to regress patients (adjusted hazard ratio, 1.73; 95% confidence interval, 1.18-2.53; P = .005). Cumulative incidences of ARM (1.1% vs 1.4%; P = .30) and aneurysm rupture (0.6% vs 0.8%; P = .20) at 4 years were both comparable in patients with and without sac shrinkage. The sac behavior at 1 year had no predictive value for aorta-related secondary intervention (hazard ratio, 3.84; 95% confidence interval 0.35-42.46; P = .259). The temporal trend of sac dynamic in both group is presented in the Figure. Aneurysm sac shrinkage at 1 year is frequent after FB-EVAR and is associated with improved patient survival, while sac enlargement affects only a minority of patients. The low incidences of ARM and aneurysm rupture indicate that failure to regress is a surrogate marker for nonaortic causes of death.