Original research
dissection, three had a Stanford type B aortic dissection and six an intramural haematoma or penetrating ulcer. Median (IQR) time from ED attendance to confirmed AAS was 6hours (3–63; n=13); one patient was diagnosed on CT scan performed prior to their ED attendance for another indication which resulted in their ED atten- dance and is not included in the analysis of time to diagnose AAS. A second patient had a CT scan prior to ED attendance which was misreported and was only diagnosed after ED attendance followed by further scan review by radiology and is included. Of note, this is the only patient who was diagnosed with AAS who had no high- risk condition, no high-risk pain feature, no high-risk examination features and a normal chest X-ray; CT showed metastatic cancer with an incidental mural thrombus and penetrating thoracic aortic ulcer. Four patients had a diagnostic delay over 24 hours from the time of ED arrival. This included the patient diagnosed on scan re-review. Thirty-three other patients had alternative aortic pathologies (4 ruptured thoracic aortic aneurysms, 5 ruptured abdominal aortic aneurysms, 21 non-ruptured thoracic or abdominal aortic aneurysms and 3 previously known stable aortic dissection/intra- mural haematoma or penetrating ulcer). Thirty-one (94%) of these were identified in the ED. This group had a 26% (9/33) 30-day mortality. No patients in our cohort were found to have been discharged with undiagnosed AAS at 30-day follow-up. Table 4 and figure 2 detail the summary test characteristics of clinical acumen, CDTs, and D-dimer (both separately and in combination) (online supplemental table 2 also includes sensi- tivity analyses). Brackets denote the range of possible values of sensitivity and specificity if all data that is currently missing in the test scores had been observed. AUROC curve for ED clini- cian AAS likelihood rating was 0.958 (95% CI 0.933 to 0.983, n=4006) and for D-dimer was 0.658 (95% CI 0.466 to 0.850, n=644). AUROC for individual CDTs were: ADD-RS 0.674 (95% CI 0.508 to 0.839, n=4989), AORTA 0.689 (95% CI 0.527 to 0.852, n=5132), Canadian 0.818 (95% CI 0.686 to 0.951, n=5180) and Sheffield 0.628 (95% CI 0.467 to 0.788, n=5092) (online supplemental figure 3). DISCUSSION This study illustrates current real-world management of AAS in EDs, and highlights the diagnostic difficulty facing ED clinicians and the limitations of methods for selecting patients for CT. Most striking is the number of patients presenting with poten- tial AAS symptoms, who did not have AAS (99.7%). Despite the low AAS prevalence, 10% with potential AAS symptoms under- went CT and 7% underwent CTA. The median time from ED arrival to confirmed AAS diagnosis was 6 hours but ranged from just over 2 hours to almost 11 days. A third of proven patients with AAS endured a diagnostic delay over 24 hours from time of ED arrival, more than the 25% reported in the literature. 2 With mortality increasing per hour of delay, 8 there is room for improvement in the management of potential AAS in the ED. Ten per cent of patients with potential AAS symptoms under went CT chest of any type (2% of scans positive for AAS). All ED-requested CT scans diagnosing AAS were CTAs (2.9% posi- tive rate for AAS). This is comparable to previous reported figures; a North American retrospective series of patients under- going CTA for suspected AAS, reported a prevalence rate of AAS on CTA of around 3%. 24 It should be noted that 40% of all CT scans detected alternative diagnoses (201 of 503), the most common are detailed in table 2. Clinicians need to use CT selec- tively yet be comfortable deciding which patients presenting with AAS symptoms do not require further investigation with CTA.
Table 3 Clinician impression of AAS ED clinician suspicion of acute aortic syndrome (AAS) AAS/dissection a possible diagnosis according to treating clinician? Yes, 1082 (24; n=4484)
ED clinician rating as to likelihood of AAS before confirmatory testing (from 0=not likely to 10=almost definitely; n=4111)
0 1 2 3 4 5 6 7 8 9
2315 (56) 694 (17) 468 (11) 272 (7)
133 (3)
71 (2) 56 (1) 47 (1) 35 (1)
11 (0.3) 9 (0.2)
10
AAS/dissection the most likely diagnosis according to treating clinician? If AAS/dissection is NOT the most likely diagnosis according to treating clinician, then most likely diagnosis(n=4267)
Yes, 151 (3; n=4574)
Acute coronary syndrome
583 (13.7)
Musculoskeletal
455 (11) 429 (10) 399 (9)
Non-specific chest pain
Acute abdomen
Non-specific abdominal pain 292 (7) Dyspepsia/oesophageal spasm 187 (4) Pulmonary embolism 158 (4) Renal colic 130 (3) Stroke 111 (3) TIA 59 (1) Subarachnoid haemorrhage 12 (0.3) CNS infection 5 (0.1) Other 1447 (34)
Data are n (%) unless stated. CNS, central nervous system; TIA, transient ischaemic attack.
online supplemental table 1 details recruitment at each of the participating EDs. Data on ED presentations (excluding minor injuries) over 16 years of age were available for 464 of the 599 (77.5%) recruitment days (60 381 presentations; mean 130.1 presentations per day), meaning there were an estimated total at all sites of 77 949 adult major presentations during the 599 study recruitment days. The study teams identified 2037 (37%) patients prospectively and 2688 (48%) patients retrospectively through EPRs or other searches, and the method of recruitment was unknown in 823 (15%) patients. Online supplemental figure 1B details the number of patients attending hospital per hour of the day, stratified by type of recruitment). Recruitment was simi- larly distributed throughout the 24-hour period with a slightly greater proportion of prospective recruitment during ‘office’ hours (online supplemental figure 2). The median age was 55 years (IQR 37–72; n=5539); 2591 (47%) patients were men (table 1). Table 2 details the clinical findings for the enrolled study population. Pain was described as sudden onset in 743 (15%), severe or worst ever in 1547 (32%), migrating or radiating in 1752 (34%) and 1609 (31%) had hypertension in ED, indicating that CDTs using these criteria will have high rates of positivity when using a low threshold. Table 3 details the results of investigations and outcome of the study population. Physician gestalt was obtained in 4111 (74%) patients prior to confirmatory testing (ie, CT/D-dimer). AAS was considered a possibility by the clinician in 1082 (24%) patients but only 407 underwent CTA. Fourteen patients (0.3%) were confirmed to have AAS: five had a Stanford type A aortic
McLatchie R, et al . Emerg Med J 2024; 41 :136–144. doi:10.1136/emermed-2023-213266
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