Morphological Analysis of Healthy Aortic Arch

This study aimed to describe an arch morphology protocol in a healthy population, and to assess the impact of age and sex.

A retrospective morphology evaluation was conducted in a population with no personal history of thoracic aorta surgery or pathology, through computed tomography (CT) imaging analysis, using a standardised protocol. Based on centreline three dimensional coordinates, a single investigator calculated a series of parameters in the arch zones and in the total arch, using Matlab scripts. These were categorized as: (i) morphometric data: diameter, length and aortic angle of each zone, total arch angle, and length; (ii) geometric data: tortuosity index (TI), arch width, assimilated curvature radius (CR_i), and attachment zone angles. Student or Mann-Whitney tests were used to compare parameter means. Their variability with age and sex was assessed through univariate and multivariate regression analysis.

CT images from 123 subjects (mean ± SD age 53 ± 19 years) were reviewed. Significant correlation between age and morphology was found. The aorta expanded homogeneously and stretched heterogeneously with age because of posterior arch elongation. TI decrease, CR_i, and attachment zone angle increase were also observed with aging. Age remained significantly associated with these morphological parameters, independently of body surface area and hypertension. Sex also affected morphology: longer total arch length and higher CR_arch in men; lower zone 3 attachment angle in women CONCLUSION: Using mathematical algorithms, and with a view to improving endovascular arch treatment, this study provides a standardised arch morphology protocol and objectively identifies both age related evolution and sex related variation in the different zones.