Background: Bicuspid aortic valve (BAV) is the most prevalent congenital heart defect affecting 1% to 2% of the population. It is associated with ascending aorta dilatation. Valve morphology, aortic stenosis (AS), and aortic insufficiency (AI) have been proposed as potential risk factors; however, evaluating their role is difficult, as these factors are inherently related. The aim of this study was to determine whether BAV morphology and dysfunction are independent determinants for ascending aorta dilatation in pediatric patients.
Methods: A multicenter, retrospective, cross-sectional study of pediatric BAV patients followed since 2004 was performed. Imaging data were assessed for BAV morphology, severity of AS and AI, history of coarctation, and aortic dimensions. Associations were determined using multivariable regression analysis. A subset of patients undergoing aortic interventions (balloon dilation or Ross) were assessed longitudinally.
Results: Data were obtained from 2122 patients (68% male; median age 10.2 years). Fifty percent of patients had ascending aorta dilatation. Right and noncoronary cusp fusion, increasing AS and AI, and older age were independently associated with ascending aorta dilatation. A history of coarctation was associated with less ascending aorta dilatation. In patients with neither AS nor AI, 37% had ascending aorta dilatation (4% severe). No complications related to aortic dilatation occurred in this cohort. Aortic Z scores were determined, and a Z-score calculator was created for this population.
Conclusions: In this large pediatric cohort of patients with BAV, valve morphology, AS, and AI are independently associated with ascending aorta dilatation, suggesting that hemodynamic factors influence aortopathy. However, even in BAVs with no AS or AI, there is significant ascending aorta dilatation independent of valve morphology. Interventions that led to changes in degree of AI and AS did not seem to influence change in aortic dimensions. The current BAV cohort can be used as a reference group for expected changes in aortic dimensions during childhood.
Keywords: bicuspid aortic valve; dilatation; hemodynamics; phenotype; risk factors.