Long-Term Growth of the Neoaortic Root After Arterial Switch Operation

Background: The growth of the neoaortic root after the arterial switch operation for the transposition of the great arteries remains unclear. This study aimed to investigate the growth of the neoaortic root and identify risk factors for neoaortic root dilatation. Methods: Serial angiographic measurements of the neoaortic root for at least 10 years were evaluated in 145 patients. A total of 1,876 measurements of the sinuses of the Valsalva and the neoaortic annuli were obtained. A linear mixed effects model was used for z-score analysis, including evaluation of risk factors for neoaortic root dilatation. To assess changes in the time course of neoaortic root absolute diameters, a nonlinear mixed effects model with a growth curve model was used. Results: The growth curve revealed progressive growth of the neoaortic root during somatic growth and stabilization in adulthood without normalization. The growth rates of the sinus and annulus were 0.0046 and 0.029 z-score per year, respectively. The sinus and annulus were estimated to grow up to 47 ± 1 mm and 31 ± 1 mm, respectively. Major risk factors for neoaortic root dilatation were double-outlet right ventricle (parameter estimate [PE] = 2.1, 95% confidence interval [CI] = 1.5 to 2.7, p < 0.0001 for sinus; PE = 1.2; 95% CI = 0.7 to 1.6, p < 0.0001 for annulus) and presence of neoaortic valve insufficiency (PE = 0.9; 95% CI = 0.4 to 1.5; p < 0.001 for sinus; PE = 1.6, 95% CI = 1.2 to 2.0, p < 0.0001 for annulus). Conclusions: The risk for neoaortic root dilatation was common. Long-term surveillance is mandatory, particularly in patients with double-outlet right ventricle and neoaortic valve insufficiency.