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Aortopulmonary Window


Lee B. Beerman

, MD, Children's Hospital of Pittsburgh of the University of Pittsburgh School of Medicine

Reviewed/Revised Apr 2023

Aortopulmonary window is an abnormal connection between the aorta and the main pulmonary artery, which causes a large left-to-right shunt. Symptoms and signs are due to heart failure Heart failure Congenital heart disease is the most common congenital anomaly, occurring in almost 1% of live births ( 1). Among birth defects, congenital heart disease is the leading cause of infant mortality... read more Heart failure , including tachypnea, poor feeding, and diaphoresis. Diagnosis is by physical examination findings, ECG, and imaging. Treatment is with surgical repair.

Aortopulmonary window is very rare and accounts for < 0.6% of all cardiac malformations. The abnormal connection can be isolated or occur with other cardiovascular abnormalities, such as atrial septal defect Atrial Septal Defect (ASD) An atrial septal defect (ASD) is an opening in the interatrial septum, causing a left-to-right shunt and volume overload of the right atrium and right ventricle. Children are rarely symptomatic... read more , ventricular septal defect Ventricular Septal Defect (VSD) A ventricular septal defect (VSD) is an opening in the interventricular septum, causing a shunt between ventricles. Large defects result in a significant left-to-right shunt and cause dyspnea... read more Ventricular Septal Defect (VSD) , coarctation of the aorta Coarctation of the Aorta Coarctation of the aorta is a localized narrowing of the aortic lumen that results in upper-extremity hypertension, left ventricular hypertrophy, and, if severe, malperfusion of the abdominal... read more , interrupted aortic arch, or tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot consists of 4 features: a large ventricular septal defect, right ventricular outflow tract obstruction and pulmonic valve stenosis, right ventricular hypertrophy, and over-riding... read more Tetralogy of Fallot . The defect results from incomplete septation of the truncus arteriosus during fetal cardiac development. The size of the direct aortic to pulmonary artery connection varies and may extend from just above the coronary sinuses to the proximal right pulmonary artery.

Pathophysiology of Aortopulmonary Window

Large left-to-right shunts cause excess pulmonary blood flow and left ventricular volume overload and also lead to lower lung compliance and higher airway resistance. The amount of left-to-right shunting leading to pulmonary overcirculation is dependent on both the size of the defect and the pulmonary vascular resistance.

Some degree of pulmonary hypertension is almost always present. The degree is determined by the size of the defect between the aorta and pulmonary artery. If the aortopulmonary connection is large, pulmonary hypertension Pulmonary Hypertension Pulmonary hypertension is increased pressure in the pulmonary circulation. It has many secondary causes; some cases are idiopathic. In pulmonary hypertension, pulmonary vessels may become constricted... read more equal to systemic pressure will be present.

Recurrent respiratory infections may occur.

If the defect is unrepaired, the high pressure and large left-to-right shunt results in pulmonary vascular disease and Eisenmenger syndrome eventually develops.

Symptoms and Signs of Aortopulmonary Window

In patients with an isolated aortopulmonary window, examination findings depend on the size of the defect and the pulmonary vascular resistance (PVR). Generally the cardiac examination reveals a parasternal lift from right ventricular overload, a loud single second heart sound (S2) resulting from pulmonary hypertension, and increased peripheral pulses.

With a large defect, the PVR may remain elevated in the first weeks or months of life, and the amount of pulmonary overcirculation is modest. The modest overcirculation results in a relatively soft basal systolic ejection murmur without a diastolic component and a loud single S2. As the PVR drops during the first months, the left-to-right shunting of blood into the lungs progressively increases, the systolic murmur becomes louder and longer and may extend into diastole, becoming a continuous murmur.

If the defect is large and unrepaired, Eisenmenger syndrome Eisenmenger Syndrome Eisenmenger syndrome is a complication of uncorrected large intracardiac or aortic to pulmonary artery left-to-right shunts. Increased pulmonary resistance may develop over time, eventually... read more eventually occurs over years with reversal of the shunt. The clinical findings may then only reveal a parasternal lift from right ventricular hypertrophy, a loud single S2 from pulmonary hypertension, absence of any murmur, and cyanosis.

Diagnosis of Aortopulmonary Window

  • Chest x-ray and ECG

  • Echocardiography and sometimes CT or MR angiography

Diagnosis is by physical examination findings, ECG, and imaging. The ECG demonstrates right ventricular hypertrophy or biventricular hypertrophy. The chest x-ray shows cardiomegaly, a large main pulmonary artery segment, and increased pulmonary vascular marking.

Echocardiography usually demonstrates the defect, but the absence of the wall between the aorta and main pulmonary artery and proximal right pulmonary artery may be relatively subtle, and the etiology of the pulmonary hypertension may initially be obscure. When findings of pulmonary hypertension are noted without an obvious intracardiac defect, the proximal great vessels should be scanned to look for a defect between the aorta and main pulmonary artery near the pulmonary artery bifurcation and proximal right pulmonary artery.

MR or CT imaging clearly defines the presence and extent of the defect. Cardiac angiography is rarely necessary, but in some instances may be helpful in clarifying the degree of shunting and pulmonary hypertension.

Treatment of Aortopulmonary Window

  • Surgical repair

Surgical repair of aortopulmonary window should be done as soon as possible after diagnosis. In rare cases, the defect may be small enough and not in proximity to the aortic valve, allowing consideration of transcatheter closure.

Key Points

More Information

The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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