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

UNLABELLED: 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.