Characterization of the Rate of Aortic Dilation in Young Patients with Thoracic Aortic Aneurysm

Longitudinal changes in aortic diameters of young patients with thoracic aortic aneurysm (TAA) have not been completely described, particularly over long periods of follow-up. This retrospective study sought to characterize the rates of proximal aortic dilation in young patients, identify risk factors for TAA progression, and evaluate the predictive utility of early echocardiographic follow-up. Inclusion criteria were: (1) TAA or TAA-predisposing genetic diagnosis, (2) age < 25 years at first echocardiogram, and (3) minimum of 5 years of echocardiographic follow-up. Proximal aortic diameters were measured by echocardiography and Z-scores calculated to index for body surface area. TAA severity was classified as no TAA (Z-score < 2), mild (Z-score 2 to 4), or at least moderate (Z-score > 4). Among 141 included patients, mean age at first echocardiogram was 7.3 ± 3.5 years. Mean follow-up duration was 9.8 ± 3.5 years. Fifty five patients had a genetic syndrome, and 38 of the non-syndromic patients had bicuspid aortic valve (BAV). The rate of aortic dilation was significantly higher at the ascending aorta than other aortic segments. BAV and age > 10 years at first echocardiogram were associated with increased rate of ascending aorta dilation. At the ascending aorta, over 25% of patients had categorical increase in TAA severity between first and last echocardiograms, and such patients demonstrated higher rate of dilation within their first 2 years of follow-up. These longitudinal findings highlight progressive ascending aorta dilation in young patients, which may worsen around adolescence. This may help determine timing of follow-up and target ages for clinical trials.