Absent aortic valve: a complex anomaly.

Seven patients (four previously cited and three new cases) with absent aortic valve cusps (leaflets), a rare and underrecognized complex congenital heart defect, are discussed. All patients were male, six full-term and one premature with nonimmunologic hydrops. None underwent operation; all died within the first week of life from low cardiac output and hypoxemia. In most instances, the only remnant of the aortic valve was a nonobstructive fibrous ridge; occasionally, it was accompanied by rudimentary leaflets or sinuses of Valsalva. Absent aortic valve was associated with other significant structural malformations in all instances, including atrioventricular valve atresia, hypoplasia or dysplasia, less commonly double outlet right ventricle, abnormal pulmonary venous connection, or left ventricular endomyocardial abnormalities. Recognition of this unusual lesion is important since it is associated with other complex malformations, causes hypoxemia (for which early positive pressure ventilation is indicated), and could be possibly palliated using the right ventricle as the systemic ventricle.