Growth of the Neo-Aortic Root and Prognosis of Transposition of the Great Arteries

Neo-aortic root dilatation can lead to significant late morbidity after the arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA). We sought to examine the growth of the neo-aortic root in d-TGA. A single-center, retrospective cohort study of patients that underwent the ASO from 07/1981-09/2022 was performed. Morphology was categorized as d-TGA with intact ventricular septum (d-TGA-IVS), d-TGA with ventricular septal defect (d-TGA-VSD), and double-outlet right ventricle-TGA type (DORV-TGA). Echocardiographically-determined diameters and derived z-scores were measured at the annulus, sinus of Valsalva (SoV), and sinotubular junction (STJ) immediately before the ASO and throughout follow-up. Trends in root dimensions over time were assessed using linear mixed-effects models. The association between intrinsic morphology and the composite of moderate-severe aortic regurgitation (AR) and neo-aortic valve or root reintervention was evaluated with uni- and multivariable Cox proportional hazards models. Of 1359 patients that underwent the ASO, 593 (44%), 666 (49%), and 100 (7%) patients had d-TGA-IVS, d-TGA-VSD, and DORV-TGA, respectively. Each patient underwent a median of 5 (IQR 3-10) echocardiograms over a median follow-up of 8.6 years (range 0.1-39.3 years). At 30 years, DORV-TGA patients demonstrated greater annular (p<0.001), SoV (p=0.039), and STJ (p=0.041) dilatation relative to d-TGA-IVS patients. On multivariable analysis, intrinsic anatomy, older age at ASO, at least mild AR at baseline, and high-risk root dilatation were associated with moderate-severe AR and neo-aortic valve or root reintervention at late follow-up (all p<0.05). Longitudinal surveillance of the neo-aortic root is warranted long after the ASO.