Thoracic Aortic Diameters and Aneurysm Prevalence in an Opportunistic Computed Tomography Screening Cohort of Adults Hospitalised with COVID-19 in Portugal: The COVID-Aorta Study.

Abstract

The aim of this study was to characterise thoracic aortic diameters across pre-defined segments in adults undergoing chest computed tomography (CT) during hospitalisation for coronavirus disease 2019 (COVID-19) in Portugal and to estimate the prevalence of thoracic aortic aneurysm (TAA) and ectasia. A retrospective cross sectional analysis of a random sample of adults hospitalised for COVID-19 between March 2020 and December 2021 who underwent chest CT as part of routine care was performed. External aortic diameters were measured at pre-defined thoracic segments using multiplanar reconstructions. Sex and age specific means and standard deviations (SD) were calculated. Median and interquartile range values are presented in the tables. TAA was defined as a segmental diameter ≥ 1.5 times the sex specific mean diameter, and ectasia as > mean + 2 SD. Prevalence estimates were calculated, and logistic regression was used to examine the association between age and TAA. Interobserver variability was assessed. A total of 763 patients were included (mean age 65 ± 18.3 years; 44.2% women). Thoracic aortic diameters progressively decreased from the arch (31 - 28 mm) to the descending thoracic aorta (27 - 23 mm). Men had larger diameters than women across all segments (mean difference 1.7 - 2.7 mm), and aortic size steadily increased with age. The overall prevalence of TAA was 1.4% (n = 11), with a similar prevalence in women (1.5%) and men (1.4%). TAA most frequently occurred in patients ≥ 75 years (2.9%). Thoracic ectasia or aneurysm was identified in 8.7% of patients, with the highest segment specific prevalence in the arch and descending thoracic aorta. Interobserver variability was minimal (< 1 mm). This study provides the first CT based thoracic aortic morphometric data in a Portuguese cohort and identified age and sex as key correlates of aortic size. Exploratory estimates of TAA and ectasia prevalence are also reported but should be cautiously interpreted given the small number of aneurysm cases.