Trends in computed tomography aortography and acute aortic syndrome in an emergency department within Aotearoa New Zealand

Abstract

Objective Acute aortic syndrome (AAS) comprises a triad of life‐threatening aortic conditions that are difficult to diagnose because of their non‐specific clinical presentations. Contrast‐enhanced computed tomography aortography (CTA) has a high sensitivity and specificity for these conditions. However, under‐ and over‐investigation of patients with suspected AAS using CTA carries significant risk. The aim of the present study was to evaluate the diagnostic imaging practices of CTA use for patients presenting to an ED with suspected AAS. Methods All atraumatic thoracic CTAs performed on patients aged ≥15 years old with suspected AAS who presented to Auckland City Hospital between 2009 and 2019 were included. Outcomes of interest were the annual ED and population incidences of AAS, and the rate of CTAs performed. Results A total of 1646 CTAs were included. There were 135 (8.2%) cases of at least one AAS diagnosis and 220 (13.4%) cases where an alternative diagnosis was made. The population‐adjusted number of AAS diagnoses remained relatively stable over the study period, with a mean annual AAS incidence of 19.6 (95% confidence interval 9.9–33.7) per 100 000 patients, and 3.2 (95% confidence interval 1.6–5.4) per 100 000 population. The number of ED presentations increased during the study period, along with the population‐adjusted rate of CTAs performed, from approximately 150 per 100 000 patients (2009) to 350 per 100 000 patients (2019). Conclusions Thoracic CTA use for investigating suspected AAS in our ED has recently increased. However, the annual incidence of AAS did not increase over the same period, but was higher than reported in overseas institutions.

Low and intermediate risk aortic dissection detection risk score and negative D-dimer: a word of caution

“…Local experiences of catastrophic outcomes contributed to by delayed imaging led to a recent retrospective cohort study of all CTAs performed in the ED at Auckland City Hospital, between 2009-2019, for the work-up of AAS. 1 Waqanivavalagi et al observed that, during the 11-year study period, there were 135 (8.2%) cases of at least one AAS diagnosis and 220 (13.4%) cases where an alternative diagnosis was made. During the study period, thoracic CTA use for investigating suspected AAS increased.…”

“…In saying this, an ADD-RS <1 coupled with a negative D-dimer as a rule-out strategy for AAS remains to be validated. 1,10 It is also plausible that the 12 high-risk clinical features comprising the ADD-RS are not sufficiently sensitive for AAS in the New Zealand population. Bhat et al analysed the Auckland cohort of patients through an ethnic lens and observed that the age-standardised AAS incidence per 100,000 ED presentations was significantly higher in Māori (6.9) and Pacific Islanders (5.3) than patients of other ethnicities (2.3).…”