Precocious Rupture of Abdominal Aortic Aneurysms Below Size Criteria for Repair: Risk Factors and Outcomes.

Background: Practice guidelines recommend elective repair for abdominal aortic aneurysms (AAAs) ≥ 5.5 cm in men and ≥ 5 cm in women to prevent rupture; however, some rupture at smaller diameters. We identify risk factors for rupture AAA (rAAA) below this threshold and compare outcomes following rAAA repair above/below size criteria.

Methods: The Vascular Quality Initiative (2013-2019) was queried for patients undergoing repair for rAAA and stratified based on diameter into small and large cohorts [Small: < 5.5 cm (men), < 5.0 cm (women)]. Univariate analysis was performed, and Kaplan-Meier analysis compared overall survival, aneurysm-related mortality, and reintervention at 12 months.

Results: Five thousand one hundred sixty two rAAA were identified. Small rAAA patients [n = 588] were more likely to have hypertension (81.3% vs. 77.0%, P < 0.02), diabetes (18.2% vs. 14.9%, P < 0.04), and end-stage renal disease (2.9% vs. 0.9%, P < 0.01) and be on optimal medical therapy (32.1% vs. 26.8%, P < 0.01). Women were more likely to rupture at smaller diameters compared to men (P < 0.01). Small rAAA patients were more likely to undergo endovascular aortic repair (EVAR) (70.2% vs. 56.0%, P < 0.01) and had lower in-hospital mortality (17.7% vs. 27.7%, P < 0.01) and fewer perioperative complications across all categories. At 12 months, small rAAA patients had better overall survival, freedom from aneurysm-related mortality, and freedom from reintervention, largely driven by EVAR approach.

Conclusions: More than 11% of patients presenting with ruptured AAA were below the recommended size threshold for repair, and they tended to be younger, non-White, and have hypertension, diabetes, and/or renal failure. Patients with small rAAA experienced lower in-hospital morbidity and mortality and improved 1-year survival, and EVAR was associated with better outcomes than open repair. However, women more frequently rupture at smaller diameters compared to men. Given contemporary elective outcomes for women, a randomized controlled trial for EVAR versus surveillance at a sex-specific size threshold is needed.