The aortic paradox: a nationwide analysis of 523,994 individual echocardiograms exploring fatal aortic dissection.

Elizabeth D Paratz; James Nadel; Julie Humphries; Stephanie Rowe; Louise Fahy; Andre La Gerche; David Prior; David Celermajer; Geoff Strange; David Playford
Abstract
Increasing aortic dilation increases the risk of aortic dissection. Nevertheless, dissection occurs at dimensions below guideline-directed cut-offs for prophylactic surgery. There is no current large-scale population imaging data assessing aortic dimensions before dissection. Patients within the National Echo Database of Australia (NEDA) were stratified according to absolute, height-indexed and body surface area (BSA)-indexed aortic dimensions. Fatal thoracic aortic dissections (ICD-10-AM code I79) were identified via linkage with the National Death Index. 524,994 individuals were assessed, comprising patients with normal aortic dimensions (n = 460,992), mild dilation (n = 53,402), moderate dilation (n = 10,029) and severe dilation (n = 572). 274,992 (52.4%) were male, with median age 64 years and median follow-up time 6.9 years. 899 fatal aortic dissections occurred (normal diameter = 610, mildly-dilated aorta = 215, moderately-dilated =53 and severely-dilated = 21). Using normal aortas as the reference population, odds of fatal dissection increased with aortic diameter (mild = OR 3.05, 95% confidence interval (CI) 2.61-3.56; moderate = OR 4.0, 95% CI 3.02-5.30; severe = OR 28.72, 95% CI 18.44-44.72). Due to the much larger number of patients without severe aortic dilation, 97.7% of fatal aortic dissections occurred in non-severely dilated aortas. Following sensitivity analysis, severe aortic dilation was responsible for at most 24.4% of fatal aortic dissections. Results were robust for absolute, height-indexed or BSA-indexed aortic measurements. Although severe aortic dilatation is associated with a near-thirty-fold increase in fatal dissection, severely dilated aortas are implicated in only 2.3-24.4% of fatal dissections. This highlights the 'aortic paradox' and limitations of current guidelines. Future studies should seek to refine risk predictors in patients without severe aortic dilation.
Journal EUROPEAN HEART JOURNAL CARDIOVASCULAR IMAGING
ISSN 2047-2412
Published 29 May 2024
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DOI 10.1093/ehjci/jeae140
Type Journal Article
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