Intrinsic Histological and Morphological Abnormalities of the Pediatric Thoracic Aorta in Bicuspid Aortic Valve Patients Are Predictive for Future Aortopathy

•Single-center, retrospective histopathologic experimental study•Non-dilated BAV ascending aortic wall samples (n=41), ranging from a premature to adult age, were studied for histopathological features.•The premature ascending aortic wall has a significantly thicker intimal and significantly thinner medial layer as compared to all other age categories.•After birth the intimal thickness decreases significantly.•Medial thickness increases significantly before adulthood with an increasing number of elastic lamellae and extracellular matrix accumulation.•Our results suggest that the main characteristics of a bicuspid aortic wall are already present before adulthood, albeit not before birth.