Hrev_master Abstract Acute Aortic Syndrome (AAS) is a life-threatening condition associated with high diagnostic uncertainty. This results in an unacceptable number of missed cases, which contributes to its high mortality. We designed and distributed a survey to Emergency Departments (EDs) across the United Kingdom to establish the standard practice for investigation and diagnosis of AAS across the UK. 56 EDs across the UK responded. The majority of these did not have a formal work-up pathway for AAS. The estimated CT scanning rates and missed cases of AAS were highly variable between departments. This suggests variation in practice and diag- nostic uncertainty. Given its time sensitive nature, the need for a more standardised diagnostic pathway for AAS in EDs is evident. This may aid clinicians rule out AAS more safely and reduce the number of missed cases, which would in turn reduce the high mor- bidity and mortality associated with AAS. Introduction Acute Aortic Syndrome (AAS) is a life-threatening condition plagued with diagnostic uncertainty.1 It constitutes Acute Aortic Dissection (AAD), intramural haematoma and penetrating aortic ulcer.2,3 The European Society of Cardiology definition also adds in aortic rupture and ruptured abdominal aortic aneurysms as part of the full scope of AAS.3 AAS accounts for 1 in 980 atraumatic chest pain attendances to the Emergency Department (ED).4 Up to 38% cases are missed during first ED presentation, and up to 25% are not diagnosed until 24 hours after ED presentation.5 This is concerning, considering mortality rises by up to 2% per hour delay in diagnosis.2,5 Lack of key clinical features and investigations sug- gesting other diagnoses are some of the reasons that AAS is missed.1,6 The Aortic Dissection Detection Risk Score (ADD-RS)7 and the Canadian Clinical Practice Guideline (CCPG)5 are two of the decision-making tools available to clinicians which can aid progression to the definitive investigation (Computed Tomography Angiography; CTA). D-Dimer has also been shown to be potential- ly discriminatory.8 Survey We reached out to 177 Type 1 EDs (which provide a 24-hour consultant-led service with full resuscitation facilities) across the Emergency Care Journal 2022; volume 18:10758 Correspondence: Aakash Gupta, Emergency Medicine Research Group Edinburgh (EMERGE), Department of Emergency Medicine, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA, UK. Tel.: +447586243990 E-mail: aakash95gupta@gmail.com Key words: Aortic dissection; diagnostic accuracy; aorta; emergency; diagnosis. Contributions: MJR, RM and SW conceived the study, AG prepared the manuscript and all authors contributed substantially to its revision. MJR takes responsibility for the paper as a whole. Conflicts of interest: All authors declare that they have no competing interests. Funding: MJR is supported by an NHS Research Scotland Career Researcher Clinician award. Availability of data and materials: Data can be made available at request. Ethical approval and consent to participate: No ethical approval was required as this was a healthcare survey and no patient identifiable data was collected. Informed consent: Survey participants were fully informed about the study on the survey landing page prior to completing the full survey, and thereafter consent was assumed for all those going on to complete and submit the survey. Received for publication: 24 July 2022. Revision received: 6 September 2022. Accepted for publication: 13 October 2022. This work is licensed under a Creative Commons Attribution 4.0 License (by-nc 4.0). ©Copyright: the Author(s), 2022 Licensee PAGEPress, Italy Emergency Care Journal 2022; 18:10758 doi:10.4081/ecj.2022.10758 Publisher's note: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organiza- tions, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its man- ufacturer is not guaranteed or endorsed by the publisher. [Emergency Care Journal 2022; 18:10758] [page 55] A sinister needle in an enormous haystack: A clinician survey regarding Acute Aortic Syndrome diagnostic practice in United Kingdom Emergency Departments Rachel McLatchie,1 Aakash Gupta,1 Sarah Wilson,2 Matthew J. Reed,1,3 Aortic Dissection Diagnosis in ED Research Group 1Emergency Medicine Research Group Edinburgh (EMERGE), Department of Emergency Medicine, Royal Infirmary of Edinburgh, Edinburgh; 2Emergency Department, Wexham Park Hospital, Frimley Health NHS Foundation Trust, Slough; 3Acute Care Group, Usher Institute of Population Health Sciences and Informatics, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, UK United Kingdom (UK) to determine standard practice for investi- gation and diagnosis of AAS. A survey was designed and sent out to lead ED consultants across the UK using an existing WhatsApp group, asking for a response on behalf of their ED. After a reminder and following a two-week window, the survey was opened to other ED clinicians via Twitter for a further 2 weeks, asking for a response on behalf of their ED. Responses were col- lated and analysed and duplicate responses excluded. Results Sixty-eight responses were received. Of these, 11 were exclud- ed due to site duplication (the first chronological response was used) and one did not state the ED site. This left 56 responses rep- resentative of 56 EDs across the UK with all four UK nations rep- resented. Of the responding EDs, 12 (21%) managed type A AADs on site while 44 (79%) did not. 30 (54%) managed type B AADs on site while 26 (46%) did not. Only 7 (12%) responding EDs had a formal AAS work-up pathway and 49 (88%) did not (Figure 1). One ED (2%) routinely used CCPG, 10 (18%) used the ADD-RS score, and 45 (80%) did not use any decision-making tools as stan- dard practice (Figure 2). Most EDs (31; 55%) do not use D-dimer to aid decision making for AAS. 10 (18%) use D-dimer as part of a clinical decision-making tool and 15 (27%) use D-dimer outwith a clinical decision-making tool. Median estimated scanning rate for AAS was 1.7 (range 0.1-6.9; n=29) per 1000 ED attendances. A median 5% of CT scans performed for AAS were positive for AAS (IQR 1-7%; n=27) with 95% being normal or showing other findings. Only 4 EDs were able to provide data on known missed cases. These varied from 0, 2 and 3-5 missed cases in the last 10 years to 3 missed cases in the last year. Conclusions This survey has demonstrated variation in approach to this diagnostic challenge across UK EDs, with indication that no diag- nostic algorithm has been widely adopted into practice. Only 1 in 8 EDs have a formal pathway to work-up a potential diagnosis of AAS and only 1 in 5 EDs use a clinical decision-making tool to help guide investigation. D-dimer is considered to have an impor- tant (yet unstandardised) role. Estimates of scan rates and missed cases show a large range suggesting diagnostic uncertainty and variable clinical practice. In such a time-critical condition, the need for standardised practice is clear. This could allow risk strat- ification of presentations to ED with common symptoms such as chest, abdominal or back pain, aiding clinicians to decide how far to investigate for AAS and also when it is safe to rule it out. This may help reduce the number of missed cases and improve morbid- ity and mortality due to AAS. References 1. Masoero M, Leotta G, Vischia F, Sechi A. Transient global amnesia: an atypical presentation of acute aortic dissection. Emerg Care J 2013;9:11. 2. Vignaraja V, Thapar A, Dindyal S. Acute aortic syndrome. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022. 3. Erbel R, Aboyans V, Boileau C, et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases: document cov- ering acute and chronic aortic diseases of the thoracic and abdominal aorta of the adult. The task force for the diagnosis and treatment of aortic diseases of the European Society of Cardiology (ESC). Eur Heart J 2014;35:2873–926. 4. Alter SM, Eskin B, Allegra JR. Diagnosis of aortic dissection in emergency department patients is rare. West J Emerg Med 2015;16:629-31. 5. Ohle R, Yan JW, Yadav K, et al. Diagnosing acute aortic syn- drome: a Canadian clinical practice guideline. CMAJ 2020;192:E832–43. 6. Levy D, Goyal A, Grigorova Y, et al. Aortic dissection. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022. 7. Nazerian P, Mueller C, De Matos Soeiro A, et al. Diagnostic accuracy of the aortic dissection detection risk score plus D- dimer for acute aortic syndromes the ADvISED prospective multicenter study. Circulation 2018;137:250–8. 8. Yao J, Bai T, Yang B, Sun L. The diagnostic value of D-dimer in acute aortic dissection: a meta-analysis. J Cardiothorac Surg 2021;16:343. Brief Report Figure 1. Response chart: Does your emergency department have a formal pathway for work-up of potential acute aortic syn- drome? Figure 2. Response chart: Does your department routinely use any of these decision-making tools in your consideration of inves- tigations for acute aortic syndrome? [page 56] [Emergency Care Journal 2022; 18:10758]