Original research
Table 1 Baseline characteristics of study population including history, past medical history, and physical examination findings of study population Demographics Median time in hours (IQR) from symptom onset to hospital presentation (n=4784) 12 (4–50) Male sex (n=5547) 2591 (47) Mean age (SD; must be 16 or over; n=5539) 55 (21) Median age (IQR; must be 16 or over; n=5539) 55 (37–72) History of presenting episode Chest pain 2903 (54; n=5422) Back pain 1211 (23; n=5301) Abdominal pain 2023 (38; n=5360) Syncope 665 (13; n=5258) Malperfusion/symptoms related to perfusion deficit 543 (11; n=5120) Neurology: paraparesis, hemiparesis/acute confusion (can be transient) 399 (8; n=5226) Pain severe intensity or worst ever 1547 (32; n=4865) Pain thunderclap/abrupt onset (including worst when awoke) 743 (15; n=4884) Pain tearing or ripping 124 (3; n=4810) Pain migrating or radiating 1752 (34; n=5086) Pregnant (if female) 81 (3; n=2535) Recent significant trauma/high speed deceleration injury 69 (1; n=5074) Recent recreational drugs including cocaine or other sympathomimetics 72 (2; n=4683) Medical history Known Marfan syndrome/connective tissue disease/giant cell arteritis 26 (0.5; n=4999) Known or family history of aortic dissection/syndrome/disease/coarctation 70 (2; n=2979) Known aortic valve disease (eg, bicuspid/dilated aortic root) 107 (2; n=4869) Recent aortic manipulation/instrumentation (within last year) 32 (1; n=4993) Known thoracic aortic aneurysm 19 (0.4; n=4987) Known abdominal aortic aneurysm 52 (1; n=4992) Physical examination findings Pulse deficit (ie, absence of one or more upper limb or femoral pulse) 49 (1; n=3400) Systolic BP differential (>20 mm Hg at any time during ED stay) 115 (5; n=2196) Focal neurological deficit 240 (5; n=5060) New aortic regurgitation murmur (ie, not previously documented) 10 (0.2; n=4806) Hypotension (SBP<90 mm Hg) or shock or pericardial effusion 143 (3; n=5192) Hypertension (SBP>140 and DBP>90) documented at any point during ED stay 1609 (31; n=5162)
Table 2 Results of investigations and outcome of study population Investigations D-dimer performed 716 (13; n=5431)
D-dimer raised (>own hospital upper limit of normal; no result available in 41)
272 (40; n=675)
CXR performed in ED
2255 (41; n=5461)
If so; abnormal mediastinum (no result available in 40)
77 (4; n=1956)
CT (any type) chest performed Of these, was this a CTA?
540 (10; n=5446) 407 (78; n=525) 5 (3–9; n=510)
Median (IQR) time from ED attendance to CT (hours) CT positive for AAS (type A/B aortic dissection, intramural haematoma or penetrating ulcer)?
12 (2; n=506)*
Alternative diagnoses found on CT/CTA 201 (40; n=503) Top five alternative diagnoses found on CT/CTA (n) Pulmonary embolism
27
LRTI/pneumonia
26 21
Aortic aneurysm (thoracic or abdominal) - non-ruptured Acute coronary syndrome including STEMI and NSTEMI
15
Cholecystitis
8
Inpatient/30-day discharge diagnoses Number with confirmed acute aortic syndrome (AAS)
14 (0.25; type A aortic dissection=5, type B aortic dissection=3, intramural haematoma/penetrating ulcer=6)
Median (IQR) time from ED attendance to confirmed AAS
6 (IQR 3–63; n=13) hours
Location of patient when AAS confirmed (n=12)
ED 11 (92) Ward 1 (8)
30-day mortality after AAS confirmed (n=12) Patients who have confirmed AAS in whom the ED clinician thinks AAS is a possible differential Patients who had confirmed AAS in whom clinician considers AAS is NOT a possible differential Patients who had confirmed AAS in whom the ED clinician thinks AAS is the most likely diagnosis ED clinician rating as to likelihood of AAS before confirmatory testing in patients with confirmed AAS (n=5353)
5 (42%; 80% CI 22% to 64%)
10 (1.0%; 80% CI 0.6% to 1.5%; n=1046)
Data are n (%) unless stated. N=5548 unless stated. DBP, diastolic BP; SBP, systolic BP.
2 (0.06%; 80% CI 0.02% to 0.16%; n=3319)
in the performance indices. We therefore calculated the perfor- mance indices according to three methods: (1) missing data was excluded and only valid data was analysed, (2) all missing data in the numerator was assumed to take a value of 0 (indicating a negative result); and (3) all missing data in the numerator was assumed to take a value of 1 (indicating a positive result). Thus, we were able to assess the dependence of each performance index on our assumptions about the missing data. Receiver operating characteristic (ROC) curve analysis was performed for the clinical decision tools (and clinical acumen, ie, ED clinician rating as to likelihood of AAS before confirmatory testing) based on their raw ordinal scores, excluding any missing data. The area under the ROC (AUROC) curve was calculated for each decision tool with 95% CIs. SPSS V.27 (IBM Corp. Released 2020. IBM SPSS Statistics for Windows, V.27.0. Armonk, New York, USA: IBM Corp) was used to produce the graphs, and R software V.4.2.1. was used to calculate the exact 80% CIs. 23 All other analyses, including descriptive analyses were performed using SAS software V.9.4 (SAS Institute, Cary, North Carolina, USA). RESULTS Between 26 September 2022 and 30 November 2022, 5548 patients presented to 27 EDs during their recruitment window, with symptoms potentially attributable to AAS (online supple- mental figure 1A). Figure 1 details participant recruitment and
5 (3.4%; 80% CI 1.7% to 6.2%; n=147)
ED clinician rating as to likelihood of AAS before confirmatory testing
Number with confirmed AAS
0 1 2 3 4 5 6 7 8 9
0 0 0 2 1 2 1 1 2 0 2
10
Number with confirmed AAS in patients in whom AAS a possible diagnosis according to treating clinician
No AAS Confirmed AAS
AAS not possible 3317
2
AAS possible
1036
10
Unknown
986
2
Data are n (%) unless stated. N=5548 unless stated. *Two patients were diagnosed on CT scans performed for another indication prior to attending ED and are not included here. One CT scan then resulted in the ED attendance. The other CT had been misreported and was only diagnosed on review. The two CT scans showed one subacute type B dissection flap, and for the other, a mural thoracic aorta thrombus and penetrating ulcer. CTA, CT aorta angiogram; LRTI, lower respiratory tract infection; NSTEMI, non-STEMI; STEMI, ST elevation myocardial infarction.
McLatchie R, et al . Emerg Med J 2024; 41 :136–144. doi:10.1136/emermed-2023-213266
139
Powered by FlippingBook