Diagnosing acute aortic syndrome: a Canadian clinical practice guideline

cute aortic syndrome (AAS) is a life-threatening emergency, accounting for 1/2000 presentations of acute chest or back pain to the emergency department. Many physicians do not consider AAS in their initial differential diagnosis, which is in part why 25% of patients with AAS are not diagnosed with the condition until 24 hours after presenting to the emergency department. rognosis is most favourable when patients are treated early, while they are clinically stable. Mortality follows a linear increase with diagnostic delay and can be as high as 2% per hour of delay. The unnecessary use of CT leads to a direct increase in health care costs but also an increase in contrast-associated complications (e.g., allergic reactions), increased length of emergency department stay or incidental findings requiring further follow-up, additional im aging and increased stress or anxiety for the patient. 17 Use of CT in a low-prevalence population can result in an increase in false-positives, which can lead to further testing, unnecessary transfer and even surgical intervention. here are 2 high-quality guidelines related to the diagnosis of AAS, from the American Heart Association (2010) and the European Society of Cardiology (2014). However, there is still considerable variation in how clinicians investigate for AAS in Canada. 17 This variation is likely multifactorial but may be a result of lack of key stakeholder involvement in the development of the guidelines or the difference in threshold for investigation within the Canadian health care system. he aims of this guideline are to update the available guideline recommendations with current evidence; include key stakeholders to allow interpretation of the evidence in context of values and preferences; and make practice recommendations that are applicable to the Canadian health care system.