ObjectivesFor neonates and infants with aortic valve pathology, the Ross procedure has historically been associated with high rates of morbidity and mortality. Data regarding long-term durability are lacking. MethodsThe international, multi-institutional Ross Collaborative included six tertiary-care centers. Infants who received a Ross operation between 1996-2016 (allowing a minimum five years of follow-up) were retrospectively identified. Serial echocardiograms were examined to study evolution in neoaortic size and function. ResultsPrimary diagnoses for the 133 patients (n=30 neonates) included isolated aortic stenosis (AS; 14%, n=19), Shone complex (14%, n=19), and AS+other (excluding Shone complex; n=95, 71%) including arch obstruction (n=55), left ventricular hypoplasia (n=9), and mitral disease (>moderate stenosis or regurgitation, n=31). At the time of Ross, median age was 96 (IQR 36-186) days and median weight was 4.4 (3.6-6.5) kg. In-hospital mortality occurred in 13/133 (10%) patients (4/30 [13%] neonates). Post-discharge mortality occurred in 10/120 (8%) patients at a median 298 days post-Ross. Post-Ross neoaortic dilatation occurred, peaking at 4-5 standard deviations above normal at 2-3 years before returning to near-baseline z-score at a median follow-up of 11.5 [6.4-17.4] years. Autograft/LVOT reintervention was required in 5/120 (4%) patients at a median 10.3 [4.1-12.8] years. Freedom from >moderate neoaortic regurgitation (AR) was 86% at 15 years. ConclusionsNeonates and infants experience excellent post-discharge survival and long-term freedom from autograft reintervention and AR following Ross. Neoaortic dilatation normalizes in this population in the long-term. Increased consideration should be given to Ross in neonates and infants with aortic valve disease.