Aortic valvar atresia

**Definition:** A congenital cardiovascular malformation in which there is no orifice of the aortic valve.

Additional information: aortic valvar atresia will most often not be coded independently, as it is frequently included within the 'Hypoplastic left heart syndrome' code as part of this spectrum of cardiovascular malformations. However, there is a small subset of patients with aortic valve atresia who have a well developed left ventricle and mitral valve and a large ventricular septal defect (nonrestrictive or restrictive).