Aneurysm Volumes After Endovascular Repair of Ruptured vs Intact Aortic Aneurysms: A Retrospective Observational Study

Purpose: To compare changes in abdominal aortic aneurysm (AAA) sac volume between endovascular aneurysm repairs (EVAR) performed for ruptured (rEVAR) vs intact (iEVAR) AAAs and to determine the impact of early volume shrinkage on future complications. Materials and Methods: A retrospective analysis was performed of all patients undergoing standard infrarenal EVAR from 2002 to 2016 at a tertiary referral institution. Only patients with degenerative AAAs and with 30-day and 1-year computed tomography angiography (CTA) imaging were included. Early sac shrinkage was defined as a volume sac reduction >10% between the first (<30-day) and the 1-year CTA. The primary endpoint was to compare AAA sac volume changes between patients undergoing rEVAR (n=51; mean age 71.0±8.5 years; 46 men) vs iEVAR (n=393; mean age 72.3±7.5 years; 350 men). Results are reported as the mean difference with the interquartile range (IQR Q1, Q3). The secondary endpoint was freedom from aneurysm-related complications after 1 year as determined by regression analysis; the results are presented as the hazard ratio (HR) and 95% confidence interval (CI). Results: At baseline, the rEVAR group had larger aneurysms (p<0.001) and shorter (p<0.001) and more angulated (p=0.028) necks. Aneurysm sac volume decreased more in the rEVAR group during the first year [−26.3% (IQR −38.8%, −12.5%)] vs the iEVAR group [−11.9% (IQR −27.5%, 0); p<0.001]. However, after the first year, the change in sac volume was similar between the groups [−3.8% (IQR −32.9%, 31.9%) for rEVAR and −1.5% (IQR −20.9%, 13.6%) for iEVAR, p=0.74]. Endoleak occurrence during follow-up was similar between the groups. In the overall population, patients with early sac shrinkage had a lower incidence of complications after the 1-year examination (adjusted HR 0.59, 95% CI 0.39 to 0.89, p=0.01). Conclusion: EVAR patients treated for rupture have more pronounced aneurysm sac shrinkage compared with iEVAR patients during the first year after EVAR. Patients presenting with early shrinkage are less likely to encounter late complications. These parameters may be considered when tailoring surveillance protocols.