Prospective study of accuracy and outcome of emergency ultrasound for abdominal aortic aneurysm over two years

Determination of the presence of an abdominal aortic aneurysm (AAA) is essential in the management of the symptomatic emergency department (ED) patient. Objectives: To identify whether emergency ultrasound of the abdominal aorta (EUS-AA) by emergency physicians could accurately determine the presence of AAA and guide ED disposition. Methods: This was a prospective, observational study at an urban ED with more than 100,000 annual patient visits with consecutive patients enrolled over a two-year period. All patients suspected to have AAA underwent standard ED evaluation consisting of EUS-AA, followed by a confirmatory imaging study or laparotomy. AAA was defined as any measured diameter greater than 3 cm. Demographic data, results of confirmatory testing, and patient outcome were collected by retrospective review. Results: A total of 125 patients had EUS-AA performed over a two-year period. The patient population had the following characteristics: average age 66 years, male 54%, hypertension 56%, coronary artery disease 39%, diabetes 22%, and peripheral vascular disease 14%. Confirmatory tests included radiology ultrasound, 28/125 (22%); abdominal computed tomography, 95/125 (76%); abdominal magnetic resonance imaging, 1/125 (1%); and laparotomy, 1/125 (1%). AAA was diagnosed in 29/125 (23%); of those, 27/29 patients had AAA on confirmatory testing. EUS-AA had 100% sensitivity (95% CI=89.5 to 100), 98% specificity (95% CI=92.8 to 99.8), 93% positive predictive value (27/29), and 100% negative predictive value (96/96). Admission rate for the study group overall was 70%. Immediate operative management was considered in 17 of 27 (63%) patients with AAA; ten patients were taken to the operating room. Conclusions: EUS-AA in a symptomatic population for AAA is sensitive and specific. These data suggest that the presence of AAA on EUS-AA should guide urgent consultation. Emergency physicians were able to exclude AAA regardless of disposition from the ED.