Ultrasound Imaging of the Abdominal Aorta: A Comprehensive Review

Ultrasound is the imaging modality of choice for the initial evaluation of disorders that involve the abdominal aorta (AA). The diagnostic value of ultrasound resides in its ability to allow assessment of the anatomy and structure of the AA using two- dimensional, three-dimensional, and contrast-enhanced imaging. Moreover, ultrasound permits evaluation of the physiologic and hemodynamic consequences of abnormalities through Doppler interrogation of blood flow, thus enabling the identification and quantification of disorders within the AA and beyond its boundaries. The approach to ultrasound imaging of the AA varies, depending on the purpose of the study and whether it is performed in a radiology or vascular laboratory or in an echocardiography laboratory. The aim of this review is to demonstrate the usefulness of ultrasound imaging for the detection and evaluation of disorders that involve the AA, detail the abnormalities that are detected or further assessed, and outline its value for echocardiographers, sonographers, and radiologists.

My Patient Has No Blood Pressure: Have They Got an Abdominal Aortic Aneurysm? Point-Of-Care Ultrasound of the Abdominal Aorta in Hypotensive Patients

Among patients presenting to the emergency department (ED) with undifferentiated hypotension, how can point-of-care ultrasound (PoCUS) help identify abdominal aortic aneurysm (AAA) as the cause of the hypotension? Many hypotensive patients in the ED are critically ill, with only minutes available to find the cause of the hypotension and treat it before the patient decompensates. While the classic description of the presentation of a ruptured AAA is of collapse with sudden onset abdominal pain and a palpable, pulsatile abdominal mass, detection of AAA by palpation is notoriously unreliable, and many patients are unaware of their underlying condition. This life-threatening situation is made even more difficult by virtue of the fact that the patient is often too unstable to travel for traditional diagnostics such as computed tomography. This article will address the use of PoCUS for the detection of AAA in the evaluation of the hypotensive patient.

Abdominal aortic aneurysm (AAA): cost-effectiveness of screening, surveillance of intermediate-sized AAA, and management of symptomatic AAA

Physicians must make decisions about screening patients for abdominal aortic aneurysms (AAAs), monitoring or referring for surgery patients with AAAs of various sizes, and assessing patients with symptoms that may be related to AAAs. This review article analyzes the evidence for each scenario. The effectiveness and cost-effectiveness of screening for AAA is based on results from four randomized controlled trials. A cost-effectiveness analysis using a Markov model showed that ultrasound screening of white men beginning at age 65 is both effective and cost-effective in preventing AAA-related death. Such screening would have a small but real impact over a 20-year period in these men. For patients with a known AAA-which is often detected incidentally-the evidence clearly suggests periodic ultrasound surveillance for those with small AAAs (3.0-3.9 cm in diameter) and elective surgical repair for those with large AAAs (>or=5.5 cm). Two recent randomized controlled trials have shown that early surgical repair confers no survival benefit compared with periodic surveillance for patients with intermediate-sized AAAs (4.0-5.5 cm in diameter), so those patients can also be monitored. Some centers choose to increase the frequency of monitoring to every 3 to 6 months when the AAA reaches 5.0 cm. Factors to consider in assessing symptomatic patients include the high risk of life-threatening conditions, the potential increased risk of death or poor outcome with delay in diagnosis, the limitations of ultrasound in identifying whether symptoms are due to known or suspected AAA, and the timely availability of computed tomography or other imaging tests. If available, computed tomography is preferred in patients with recent or severe symptoms, since it is better at detecting retroperitoneal hemorrhage and other complications and in providing preoperative definition of the anatomy.