An aortopulmonary window is a relatively rare anomaly that can occur either as an isolated defect or in association with other congenital lesions, such as ventricular septal defect, atrial septal defect, interrupted aortic arch, and tetralogy of Fallot. The defect classically occurs between the main pulmonary artery and aorta just above the level of the sinuses of Valsalva (Fig. 26-1A). Occasionally, the defect may be at the origin of the right pulmonary artery (Fig. 26-1B). Rarely, the right pulmonary artery may actually have a separate anomalous origin from the aorta (Fig. 26-1C). Many classification systems exist, but using the terms proximal, distal, total, and intermediate may be useful in planning the approach. Proximal defects have a minimal inferior rim, distal defects have little superior rim, and most of the ascending aorta is involved with a total aortopulmonary window. The intermediate form has adequate rims circumferentially, and is the type, which potentially could be closed by a transcatheter device.

Although simple ligation or division between clamps has been successfully performed in the past, closure of the defect under direct vision with the aid of cardiopulmonary bypass is now the method of choice. This prevents serious hemorrhagic complications that can occur because of the fragility of the great vessel walls, and allows precise closure of the various forms of the defect. The diagnosis is made with echocardiography, and closure of the aortopulmonary window is indicated without delay to prevent the development of pulmonary vascular disease.