Aortopulmonary Window (AP Window)
Aortopulmonary window (AP window) is a congenital heart defect characterized by a communication between the ascending aorta and the pulmonary artery in the presence of separate semilunar valves. It is a rare malformation representing less than 0.5% of the congenital heart disease and is often associated with other cardiac defects in 25-50% of the cases such as VSD, aortic arch anomalies, anomalous origin of the coronary arteries and tetralogy of Fallot. The physiology of an AP window is a left-right shunt lesion and therefore, when this malformation is isolated and large, postnatally, patients may present with pulmonary overcirculation, congestive heart failure, pulmonary hypertension and early development of pulmonary vascular disease.
Type I: The defect is more proximal located between the origin of the main pulmonary artery and the ascending aorta immediately above the sinus of Valsalva (deficient septation of the aortopulmonary trunk). These defects tend to be large, round or oval shaped.
Type II: The defect is more distal, between the ascending aorta and the origin of the right pulmonary artery (abnormal migration of the 6th aortic arch). These defects are more rare and tend to be smaller in size.
Type III: A large defect combining the other two types
References:
Gargana et. al. Aortopulmonary window- impact of associated lesions on surgical results. Arq Bras Cardiol. 2007 Apr;88(4):402-7.
Kuehn et al. Aortopulmonary window with ventricular septal defect and pulmonary atresia: prenatal diagnosis and successful early correction. Ultrasound Obstet Gynecol. 2004