Replacement of the aortic valve with cryopreserved aortic valve allograft: considerations and techniques in children

Normal structure and function of the aortic valve requires not only the basic three-cusp architecture but also the dynamic action and shape of the aortic sinuses and correct diameter relationships at the left ventricular outlet and at the aortic sinus rim. Congenital malformation of the aortic valve implies abnormality of the aortic cusps and, additionally, there may be deformity of the aortic sinuses or the subvalvular left ventricular outflow tract or the supravalvular aorta. Aortic valve replacement in children using an aortic valve allograft often requires enlargement of the left ventricular outflow tract or restoration of aortic sinus configuration. Careful consideration of the malformations of the aortic root and planning of reconstructive operation is required lest the malformation be recreated in the allograft valve replacement. Even the best execution of known aortic root reconstructive or left ventricular outflow tract enlarging operations has limitations in restoration of normal structure and compliance of the aortic root. Consequently, there remain many unknown factors that could affect late results of aortic valve allograft operations in children compared to those results observed in adult patients.