aortopulmonary

Aortopulmonary window (APW) is a rare congenital heart defect defined by an abnormal communication between the ascending aorta and the main pulmonary artery, creating a direct left-to-right shunt. The defect is usually located above the semilunar valves and can occur in isolation or in combination with other congenital anomalies.

Anatomy and classification: APW results from incomplete separation of the aortic and pulmonary outflow tracts during embryogenesis. The communication can vary in location relative to the semilunar valves, and is commonly described as proximal or distal variants, with several anatomical descriptions used in the literature.

Pathophysiology: The aortopulmonary communication allows systemic blood to flow into the pulmonary circulation, producing pulmonary overcirculation. The resultant left-to-right shunt can lead to congestive heart failure in infancy, pulmonary hypertension, and, if uncorrected, progressive pulmonary vascular disease.

Clinical presentation: Infants may present with tachypnea, poor feeding, failure to thrive, and recurrent respiratory infections. A heart murmur, which may be continuous or systolic, is often detected on examination, reflecting increased pulmonary flow.

Diagnosis: Transthoracic echocardiography is the primary diagnostic tool, enabling visualization of the defect and assessment of associated anomalies. Cross-sectional imaging (CT or MRI) can further delineate anatomy in complex cases. Cardiac catheterization is used selectively to evaluate hemodynamics before surgery.

Management and prognosis: The definitive treatment is surgical repair to close the defect and restore separation of the great arteries. Repair may involve direct closure or patch repair, often performed early in life. Outcomes have improved with timely surgery, though delayed repair increases the risk of pulmonary vascular disease and residual issues. Long-term follow-up is advised to monitor pulmonary and cardiac health.

See also: truncus arteriosus; patent ductus arteriosus; congenital heart defect.