RS10 - Primary Saccular Abdominal Aortic Aneurysms: Natural History and Contemporary Management

Objectives: Saccular abdominal aortic aneurysms (sAAAs) are often repaired based upon morphology alone due to their unknown rupture risk. There is limited data documenting the natural history of these aneurysms, and as a result, there is no consensus for selective interventions in these patients. This study sought to ascertain the natural history of sAAAs, and thus define their appropriate management strategy.

Methods: A single institution’s medical record system was queried to identify all patients with sAAAs. Computed tomography images were available in this population from the years 2000 to 2021. Primary end points included change in size over time, rupture, presence of symptoms, and intervention.

Results: 2497 infrarenal abdominal aortic aneurysms were identified. Of these, 2424 were fusiform in morphology (97.1%) and 73 were saccular in morphology (2.92%). 12 sAAAs were repaired (16.4%). 100% of repairs were endovascular. 1 was repaired for symptoms (8.3%), 4 were repaired for diameter >5.0 cm (33.3%), and 7 were repaired for morphology alone (58.3%). 28.8% of sAAAs evaluated by vascular surgeons were not repaired at the time of this analysis. 54.8% of sAAAs had never been referred to a vascular surgeon.

There was a median surveillance time of 4.0 years for untreated sAAAs vs 6.5 years for treated sAAAs. There was a mean growth rate of 0.93 mm/year for untreated sAAAs (95% CI 0.64-1.22) vs 0.63 mm/year for treated sAAAs (95% CI 0.28-0.99) during surveillance. The mean growth rate of sAAAs during surveillance in both groups combined was 0.87 mm/year (95% CI 0.62-1.12).

When growth rate was compared with initial sAAA diameter upon discovery, there was no significant correlation, with an R2 value of 0.0002.

100% of subjects treated for sAAA were living at the time of this analysis. There was a 36% all-cause mortality in the untreated group with a mean duration of sAAA discovery to death of 4.8 years. None of the deaths in the untreated group were related to aortic pathology. Additionally, no ruptures were identified in the sAAA group.

Conclusions: SAAA is a distinct abdominal aortic entity with a benign course and rare risk of rupture. The current practice of repair regardless of size may not be justified.