Echocardiography in the emergency assessment of acute aortic syndromes

Acute aortic syndrome (AAS) is a collective term for several life-threatening acute aortic conditions: aortic dissection, intramural haematoma (IMH), penetrating atherosclerotic ulcer, and traumatic transection. Mortality from acute ascending aortic (type A) dissection increases rapidly immediately after presentation, reaching 1-2% per hour for the first 48 h. Early surgical intervention is recommended for type A aortic dissection and has been shown to improve outcome. Transthoracic echocardiography is an extremely valuable, often overlooked, clinical tool in diagnosing and assessing AAS in the emergency setting. Although diagnostic sensitivity is suboptimal, it is very useful in assessing potential high risk features or complications, such as pericardial effusion, and diagnosing potential differential conditions. A negative transthoracic echocardiography (TTE), however, does not exclude AAS. In patients with a high risk of type A dissection or IMH (identified clinically or by TTE), the safest and most rapid 'gold standard' investigation is transoesophageal echocardiography, ideally performed with the cardiac surgical team standing by. This is of particular importance in the haemodynamically unstable patient. Transoesophageal echocardiography, helical CT, and MRI have similar diagnostic accuracy and, when there is diagnostic uncertainty or no indication for immediate intervention, should be used according to clinical need, local availability, and expertise.