The DAShED (Diagnosis of Aortic Syndrome in the ED) Study
- Conditions
- Aortic Dissection
- Registration Number
- NCT05582967
- Lead Sponsor
- NHS Lothian
- Brief Summary
Acute aortic syndrome (AAS) is a life-threatening emergency condition affecting the upper aorta affecting \~4000 people in the (United Kingdom; UK) a year with an ED misdiagnosis rate as high as 38%. Previous research has identified several strategies combining clinical probability scoring with blood tests (D-Dimer) to rule out the condition but when applied to a large population (ED) with relatively low numbers of actual cases, these result in a high rate of computed tomographic angiography (CTA) scanning. Current guidelines reflect the uncertainty of existing evidence.
This study, the first phase of three, aims to describe the characteristics of ED attendances with possible AAS, to determine the service implications of using different diagnostic strategies and inform future research. The investigators plan to recruit all ED attendances with possible AAS over a 1-4 week period. The investigators plan a prospective and retrospective approach to data collection adopting a waived-consent strategy with endpoint measures describing the characteristics of patients presenting with possible AAS.
- Detailed Description
AAS is a life-threatening emergency condition which presents to the ED. Around 4,000 people suffer per year in the UK \[1\], many not receiving timely diagnosis and treatment. 25% of patients are not diagnosed until 24 hours after arriving in the ED due to the varied nature of presentation \[2\]. Chest pain is the most common presenting symptom of AAS (80%) although back pain (40%) and abdominal pain are not uncommon \[1\]. These symptoms account for over 2 million ED attendances per year in England \[National Health Service; NHS Digital A\&E 2021\] and are overwhelmingly due to causes other than AAS. The estimated incidence of AAS is 1 in every 980 ED attendances with atraumatic chest pain \[3\], thus creating a substantial diagnostic challenge.
Prognosis is best when patients are treated early, and mortality increases 2% per hour of delay. \[4\] The misdiagnosis rate during the initial ED visit for AAS is estimated to be between 1 in 3 to 1 in 7 AASs \[5\], leading to worse outcomes \[6,7\] whilst CTA over testing leads to diagnostic yields as low as 2-3%. \[2,8\]. CTA scanning of the aorta has high sensitivity and specificity for diagnosing AAS, but an unrestricted CT strategy will incur significant costs, has ionising radiation risks, resource implications, CT delays for non-AAS patients and the burden of 'incidentalomas'.
Clinicians therefore need to use CTA selectively but there is no validated scoring system to help this decision. Several have been proposed \[1, 9-14\] including the ADD-RS score, the Canadian clinical practice guideline Clinical Decision Aid \[13\], the AORTAs score \[14\] and the Sheffield score \[unpublished\]. D-Dimer has been suggested as a rule-out biomarker in low pre-test probability patients (95-98% sensitivity) \[15,16\] and has been incorporated into the Aortic Dissection Detection-Risk Stratification (ADD-RS) score to reduce CTA rate in low pre-test probability patients. None have been studied in truly undifferentiated ED populations, or in the UK where CTA threshold is different compared to North America. It is currently unclear whether any have sufficient sensitivity to be acceptable to clinicians, which is the most accurate, and whether they are likely to lead to CTA and D-Dimer over testing. Assessment of CTA rate and CT positivity has also not previously been studied. The Royal College of Emergency Medicine has recently released a national guideline advocating any patient with an ADD-RS score of \>=1 (no D-dimer incorporated) should have a CT aorta performed (unless other cause for symptoms identified and evidenced). The recommendation is not based on UK-validated clinical evidence, however, and clinical impacts of the recommendation are yet to be seen.
In view of these diagnostic challenges, the investigators aim in our programme of work to ultimately to assess which of the four aforementioned clinical decision tools is most effective, assess external validity, and assess clinical impact. This study (Phase 1; DAShED) will involve prospective data collection on all characteristics of four different risk scores, in addition to evaluation of patient characteristics, potential CT aorta rates with different strategies, and enrolment rates at participating sites. This will inform Phase 2, which will involve full interventional external validation study of the decision aid(s) selected in Phase 1 (including biomarker collection); the main objective being to select the score to subject to assessment of clinical impact (intervention step-wedge trial) in Phase 3.
This is an observational cohort study of all people attending the ED with symptoms of possible AAS, including new-onset chest, back or abdominal pain, syncope or symptoms related to malperfusion.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 5548
- People attending the ED with symptoms of AAS, including those with new-onset chest, back or abdominal pain, syncope or symptoms related to malperfusion.
- β₯16 years old
- No symptoms of AAS.
- <16 years old
Study & Design
- Study Type
- OBSERVATIONAL
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method Median time from hospital presentation to imaging diagnosis and median time from symptom onset to hospital presentation (hours) 30 days Median time from hospital presentation to imaging diagnosis and median time from symptom onset to hospital presentation (hours)
Enrolment rate at each participating site 30 days Number of participants during study period enrolled
Number of AAS patients not enrolled due to lack of clinical/research support 30 days Number of AAS patients not enrolled due to lack of clinical/research support
Test characteristics Aorta score 30 days Test characteristics of Aorta score (i.e. sensitivity, specificity, positive predictive value, negative predictive value)
Test characteristics of Canadian guideline score 30 days Test characteristics of Canadian guideline score (i.e. sensitivity, specificity, positive predictive value, negative predictive value)
Proportion of patients in whom the ED clinician thinks Acute Aortic Syndrome (AAS) is a possible differential who have confirmed AAS 30 days Proportion of patients in whom the ED clinician thinks Acute Aortic Syndrome (AAS) is a possible differential who have confirmed AAS
CT angiogram (CTA) ordering and positivity rate 30 days Number of CT angiograms ordered and the proportion that are positive scans
Test characteristics of Sheffield AAS decision rule 30 days Test characteristics of Sheffield AAS decision rule (i.e. sensitivity, specificity, positive predictive value, negative predictive value)
Proportion of patients in whom ED clinician considers AAS NOT a possible differential who had confirmed AAS 30 days Proportion of patients in whom ED clinician considers AAS NOT a possible differential who had confirmed AAS
Test characteristics of clinical acumen 30 days Test characteristics of clinical acumen (i.e. sensitivity, specificity, positive predictive value, negative predictive value)
Test characteristics of D-dimer 30 days Test characteristics of D-dimer (i.e. sensitivity, specificity, positive predictive value, negative predictive value)
30-day mortality in proven AAS 30 days 30-day mortality in proven AAS
Proportion of alternative diagnoses found on CTA and final hospital diagnosis 30 days Proportion of alternative diagnoses found on CTA and final hospital diagnosis
Test characteristics of ADD-RS (Aortic Dissection Detection-Risk Score) 30 days Test characteristics of Aortic Dissection Detection-Risk Score (i.e. sensitivity, specificity, positive predictive value, negative predictive value)
Number of patients not able to be enrolled with reason why not enrolled 30 days Number of patients not able to be enrolled with reason why not enrolled
- Secondary Outcome Measures
Name Time Method
Trial Locations
- Locations (25)
Luton & Dunstable University Hospital
π¬π§Luton, United Kingdom
Royal United Hospital
π¬π§Bath, United Kingdom
Bristol Royal Infirmary
π¬π§Bristol, United Kingdom
North Bristol NHS Trust
π¬π§Bristol, United Kingdom
Addenbrookes hospital
π¬π§Cambridge, United Kingdom
Frimley Health
π¬π§Frimley, United Kingdom
St Johns Hospital
π¬π§Edinburgh, United Kingdom
Royal Infirmary of Edinburgh
π¬π§Edinburgh, United Kingdom
James Paget University Hospital
π¬π§Great Yarmouth, United Kingdom
Queen Elizabeth University Hospital
π¬π§Glasgow, United Kingdom
Royal Alexandra Hospital
π¬π§Glasgow, United Kingdom
Victoria Hospital
π¬π§Kirkcaldy, United Kingdom
Lewisham and Greenwich NHS Trust
π¬π§Lewisham, United Kingdom
Harrogate
π¬π§Harrogate, United Kingdom
Raigmore
π¬π§Inverness, United Kingdom
Queen Elizabeth Hospital NHS Foundation Trust
π¬π§King's Lynn, United Kingdom
Milton Keynes Universoty Hospital NHS Foundation Trust
π¬π§Milton Keynes, United Kingdom
Wythenshawe Hospital
π¬π§Manchester, United Kingdom
Royal Oldham Hospital
π¬π§Oldham, United Kingdom
John Radcliffe Hospital
π¬π§Oxford, United Kingdom
Royal Victoria Infirmary
π¬π§Newcastle, United Kingdom
Royal Berkshire NHS Foundation Trust
π¬π§Reading, United Kingdom
Royal Glamorgan Hospital
π¬π§Pontyclun, United Kingdom
Sheffield Teaching Hospitals NHS Foundation Trust
π¬π§Sheffield, United Kingdom
Wexham Park
π¬π§Slough, United Kingdom