When to stop: Optimizing abdominal aortic aneurysm surveillance in the elderly.

Abstract

Many older adults with asymptomatic abdominal aortic aneurysms (AAAs) smaller than the recommended intervention diameter may not benefit from lifelong surveillance. This study aimed to identify subgroups with a low likelihood of AAA progression to the intervention diameter relative to death based on age, comorbidities, and aneurysm size. We used the multicenter, aneurysm registry data of an integrated health system from 2007 to 2024. Patients aged 65 years or older were included, and comorbidities were stratified using an internally validated risk index. The AAA size at the first scan was determined through ultrasound or cross-sectional imaging. Quantile regression with time-to-event analysis was utilized. The composite event included death, progression to the intervention size (5 cm in women, 5.5 cm in men), or AAA intervention. Both the time to the first event and the probability that the first event was death, rather than aneurysm progression, were determined across ages and aneurysm sizes for those with a median comorbidity score. A >90% probability of death as the first event was the cutoff for surveillance cessation. This analysis was replicated for hypertensive smokers or never smokers at the 20th and 80th percentile comorbidity scores. A total of 10,629 patients meeting the inclusion criteria were identified. The median age was 74 years; 80.3% were male. The median starting aneurysm size for both genders was 3.5 cm. The 10-year mortality rate was 62%. In unadjusted analyses, among women, the following percentages of AAA of certain sizes reached operable size before death: 14.6% of aneurysms with sizes of 2.7 to 3.4 cm, 39.3% with sizes of 3.5 to 4 cm, 60% with sizes of 4 to 4.5 cm, and 79% with sizes of 4.5 to 5 cm. For men, the percentages were as follows: 7.9% of aneurysms with sizes of 2.7 to 3.4 cm, 59.1% with sizes of 3.5 to 4 cm, 47.5% with sizes of 4 to 4.5 cm, and 73.6% with sizes of >5 cm. In the model, women older than 85 years with aneurysms smaller than 3.5 cm had a ≥90% probability that their first event was death and not progression to the intervention threshold; this was true for men aged >80 years with aneurysms smaller than 3.5 cm. In patients with higher comorbidity burdens (80th percentile comorbidity score, current or former smokers), there was a ≥90% probability of death before reaching the operative size for men aged 75 years and older with AAA sizes of 2.7 to 3.4 cm, men aged 85 years or older with AAA sizes of <4 cm, and women aged 85 years or older with AAA sizes of 2.7 to 3.4 cm. Surveillance can cease for women aged 85 years or older or men aged 80 years or older with aneurysms smaller than 3.5 cm because the probability of death before aneurysm progression is >90%. Factoring in comorbidity burdens in addition to age and aortic diameter facilitates patient-specific recommendations to optimize surveillance.