Aneurysm Sac Shrinkage at 1 Year after Fenestrated-Branched Endovascular Aortic Repair of Complex Aortic Aneurysms Offers Mid-Term Survival Advantage

Abstract

To investigate the impact of 1-year changes in aneurysm sac diameter on patient survival after fenestrated-branched endovascular aortic repair (FB-EVAR) of complex abdominal (CAAA) or thoracoabdominal aortic aneurysms (TAAA). We reviewed the clinical data of patients enrolled in a prospective non-randomized study investigating FB-EVAR (2013-2022). Patients with sequential follow up computed tomography (CT) scans at baseline and 6 to 18 months after FB-EVAR were included in the analysis. Aneurysm sac diameter change was defined as the difference in maximum aortic diameter (MAD) from baseline measurements obtained in centerline of flow. Patients were classified as those with sac shrinkage (≥5mm) or failure to regress (<5mm or expansion) according to sac diameter change. Primary endpoint was all-cause mortality. Secondary endpoints were aortic-related mortality (ARM), aortic aneurysm rupture (AAR) and aorta-related secondary intervention. There were 549 patients treated by FB-EVAR. Of these, 463 patients (71% male, mean 74±8 years-old) with sequential CT imaging were investigated. Aneurysm extent was TAAA in 328 (71%) patients and CAAA in 135 (29%). Sac shrinkage occurred in 270 (58%) patients and failure to regress in 193 (42%) patients, including 19 (4%) patients with sac expansion at 1-year. Patients from both groups had similar cardiovascular risk factors, except for younger age among patients with sac shrinkage (73±8 vs. 75±8 years-old; P<.001). Median follow-up was 38 months (interquartile range, 18-51 months). Five-year survival estimate was 69%±4.1% for sac shrinkage and 46%±6.2% for failure to regress group. Survival estimates adjusted for confounders (age, chronic pulmonary obstructive disease, chronic kidney disease, congestive heart failure, and aneurysm extent) revealed a higher hazard of late mortality in patients with failure to regress (adjusted hazard ratio, 1.72; 95% confidence interval, 1.18-2.52; P=.005). Five-year cumulative incidences of ARM (1.1% vs. 3.1%, P=.30), AAR (0.6% vs. 2.6%, P=.20) and aorta-related secondary intervention (17±2.8% vs. 19±3.8%) were both comparable between the groups. 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 AAR indicate that failure to regress may serve as a surrogate marker for non-aortic-related death.