Acute aortic syndrome: nationwide study of epidemiology, management, and outcomes

Abstract

Background: Epidemiological studies on acute aortic syndrome (AAS) have relied largely on unverified administrative coding, leading to wide-ranging estimates of incidence. This study aimed to evaluate the incidence, management, and outcomes of AAS in Aotearoa New Zealand.

Methods: This was a national population-based retrospective study of patients presenting with an index admission of AAS from 2010 to 2020. Cases from the Ministry of Health National Minimum Dataset, National Mortality Collection, and the Australasian Vascular Audit were cross-verified with hospital notes. Poisson regression adjusted for sex and age was used to investigate trends over time.

Results: During the study interval, 1295 patients presented to hospital with confirmed AAS, including 790 with type A (61.0 per cent) and 505 with type B (39.0 per cent) AAS. A total of 290 patients died out of hospital between 2010 and 2018. The overall incidence of aortic dissection including out-of-hospital cases was 3.13 (95 per cent c.i. 2.96 to 3.30) per 100 000 person-years, and this increased by an average of 3 (95 per cent c.i. 1 to 6) per cent per year after adjustment for age and sex adjustment on Poisson regression, driven by increasing type A cases. Age-standardized rates of disease were higher in men, and in Māori and Pacific populations. The management strategies used, and 30-day mortality rates among patients with type A (31.9 per cent) and B (9.7 per cent) disease have remained constant over time.

Conclusion: Mortality after AAS remains high despite advances over the past decade. The disease incidence and burden are likely to continue to increase with an ageing population. There is impetus now for further work on disease prevention and the reduction of ethnic disparities.

Fig. 1

Study flow chart AVA, Australasian Vascular Audit; AAS, acute aortic syndrome; TEVAR, thoracic endovascular aortic repair; NMDS, National Minimum dataset; ED, emergency department; NZ, New Zealand; MORT, National Mortality Collection.

Fig. 2

Yearly incidence of aortic dissection over study interval Incidence of a type A and b type B acute aortic syndrome (AAS), and c out-of-hospital mortality owing to AAS over time; d incidence of all in-hospital cases of AAS until 2020 year end, and of all cases of AAS including out-of-hospital deaths until 2018 year end. Data for out-of-hospital deaths from AAS are complete to only 2018. Rates presented are age- and sex-standardized to the Aotearoa New Zealand population based on 2013 and 2018 census data, with linear interpolation. Shaded areas represents 95 per cent confidence intervals.

Fig. 3

Yearly 30-day mortality rate of in-hospital cases of acute aortic syndrome over study interval Shaded areas represents 95 per cent confidence intervals. Stratified by a type A, b type B, and c all cases.