CME Information : Clinical Examination for Acute Aortic Dissection : A Systematic Review and Meta-analysis

Objectives: Acute aortic dissection is a life-threatening condition due to a tear in the aortic wall. It is difficult to diagnose and if missed carries a significant mortality. Methods: We conducted a librarian-assisted systematic review of PubMed, MEDLINE, Embase, and the Cochrane database from 1968 to July 2016. Titles and abstracts were reviewed and data were extracted by two independent reviewers (agreement measured by kappa). Studies were combined if low clinical and statistical heterogeneity (I < 30%). Study quality was assessed using the QUADAS-2 tool. Bivariate random effects meta analyses using Revman 5 and SAS 9.3 were performed. Results: We identified 792 records: 60 were selected for full text review, nine studies with 2,400 participants were included (QUADAS-2 low risk of bias, j = 0.89 [for full-text review]). Prevalence of aortic dissection ranged from 21.9% to 76.1% (mean SD = 39.1% 17.1%). The clinical findings increasing probability of aortic dissection were 1) neurologic deficit (n = 3, specificity = 95%, positive likelihood ratio [LR+] = 4.4, 95% confidence interval [CI] = 3.3–5.7, I = 0%) and 2) hypotension (n = 4, specificity = 95%, LR+ = 2.9 95% CI = 1.8–4.6, I = 42%), and decreasing probability were the absence of a widened mediastinum (n = 4, sensitivity = 76%-95%, negative likelihood ratio [LR–] = 0.14–0.60, I = 93%) and an American Heart Association aortic dissection detection (AHA ADD) risk score < 1 (n = 1, sensitivity = 91%, LR– = 0.22, 95% CI = 0.15–0.33). Conclusions: Suspicion for acute aortic dissection should be raised with hypotension, pulse, or neurologic deficit. Conversely, a low AHA ADD score decreases suspicion. Clinical gestalt informed by highand low-risk features together with an absence of an alternative diagnosis should drive investigation for acute aortic dissection. Acute aortic dissection is a life-threatening emergency, accounting for o in 2000 presentations of acute chest/back pain. If untreated, mortality increases by 1% to 2% every hour from initial presentation and may reach a high of 40% in the acute period and 70% in 2 weeks. Emergency medicine physicians fail to diagnose aortic dissection in 38% of cases and in those they correctly identify, 25% remain undiagnosed for greater than 24 hours. Patients who are often missed include those presenting without classic features of aortic dissection (pulse deficit, widened mediastinum) or signs of an alternative diagnosis such as acute coronary syndrome (electrocardiogram evidence of ischemia, anterior chest pain) or those who appear well (walk in patients). Although 90% of aortic dissection patients present with pain, it is difficult to identify these cases when From the Department of Emergency Medicine, Ottawa Hospital Research Institute (RO), the Department of Undergraduate Medicine (HKK), and the Department of Epidemiology and Community Medicine (GW), University of Ottawa, Ottawa, Ontario; and the Cardiovascular Research Methods Centre, University of Ottawa Heart Institute (GW, JJP), Ottawa, Ontario, Canada. Received September 8, 2017; revision received November 22, 2017; accepted December 1, 2017. Presented at the Canadian Association of Emergency Physicians Scientific Annual Meeting, Quebec City, QC, Canada, May 2016. The authors have no relevant financial information or potential conflicts to disclose. Supervising Editor: Christopher R. Carpenter,MD. Address for correspondence and reprints: Dr. Robert Ohle; e-mail: Robert.ohle@gmail.com. ACADEMIC EMERGENCY MEDICINE 2018;25:398–412. 398 ISSN 1553-2712 © 2017 by the Society for Academic Emergency Medicine doi: 10.1111/acem.13360 taken in context of the vast number of other patients also presenting with acute pain from an alternative cause. The varying location of the dissection and the involvement of branch vessels give rise to a myriad of associated symptoms. Chest, back, and abdominal pain are all common emergency department (ED) complaints while aortic dissection is quite rare so choosing wisely those who require advanced testing is challenging. The most comprehensive study on clinical presentation of acute aortic dissection is the International Registry of Acute Aortic Dissection (IRAD), a multicenter research coalition founded in 1996 that continuously evaluates the management and outcomes of acute aortic dissection. This large international prospective case series presents data only on patients diagnosed with acute aortic dissection; thus it is impossible to ascertain specificity of reported clinical findings. There has been one previous systematic review by Klompas in 2002. Our objective was to conduct an updated systematic review and meta-analysis to assess the diagnostic accuracy in acute aortic dissection of history, physical, and plain radiographs compared to advanced imaging in adult patients presenting to the ED with a clinical suspicion of acute aortic dissection.