RS13 - A Population-Based Approach to Abdominal Aortic Aneurysm Surveillance is Associated with Guideline Concordant Care

Objectives: The majority of abdominal aortic aneurysms (AAAs) detected incidentally or through targeted screening are small and require surveillance, while larger AAAs may require vascular surgery (VS) evaluation and intervention. However, prior studies have reported poor follow-up for AAA patients, particularly those with small AAAs, and large-scale surveillance program outcomes are unreported in U.S.-based health systems. This study describes an established AAA surveillance program and examines its impact on concordance with surveillance guidelines.

Methods: Patients for this descriptive study came from a prospective AAA surveillance program established in 2003, within a large integrated health system. The nucleus of the program was a nurse-managed registry embedded in the electronic health record, which was alerted for new AAA diagnoses and relevant radiology studies to complement standard primary care provider driven care (Figure). Radiology reporting of AAAs was standardized and included recommendations for surveillance imaging or VS referral. Timely imaging or referral was ensured by program oversight and communication with clinical stakeholders. The cohort consisted of registry patients who had an AAA (infrarenal aorta ≥ 3.0 cm) identified between May 24, 2012 and October 25, 2016 with follow-up through 2020. Cohort patients were assessed for guideline-concordant care within the study period, which was defined as receiving surveillance imaging, VS clinic appointment, or surgical repair using diameter-specific time intervals.

Results: Among the cohort of 6,524 patients, the mean age was 75.0 years, 81.0% were male, and 73.2% were current or former smokers. 3,107 (47.6%) had AAAs 3.0-3.4 cm and only 151 (2.0%) had aneurysms larger than 5.5 cm at baseline (Table). Within the health system’s recommended diameter-specific surveillance intervals, 85.4% of the cohort had follow-up (imaging surveillance, VS clinic visits, or AAA repair) concordant with institutional guidelines, which ranged from 82.1% among patients with AAAs 3.0-3.4cm to 90.9% among patients with AAAs 4.0-5.4cm. Among patients with AAAs 3.0-3.4 cm, 80.8% received imaging surveillance within 2 ½ years. Among patients with AAAs 4.0-5.4 cm, 88.4% received imaging surveillance within 1 1/3 years, and 11.6% underwent surgery within that time.

Conclusions: A dedicated surveillance program that leverages structured radiology reporting and electronic health record integration is associated with excellent AAA surveillance and follow-up. This effort can enhance AAA awareness, streamline processes for clinical stakeholders and mitigate the consequences of failure to receive adequate and timely follow-up. Targeted AAA screening can then exist in combination with such a surveillance program to more effectively reduce the morbidity and mortality of this condition.