Ultrasound diagnosis of pulmonary sling with proximal stenosis of left pulmonary artery and patent arterial duct

Authors discuss methods of echocardiographic diagnosis of the pulmonary sling with stenosis and hypoplasia of the left pulmonary artery and patent arterial duct with massive left-to-right shunt, based on a case of the newborn with resistant to treatment heart failure, with initial diagnosis of patent ductus arteriosus, referred to surgical treatment. The optimal echocardiographic views permitting establish diagnosis of the pulmonary sling were suggested. The special attention was paid to high parasternal and suprasternal views visualizing vessels of the upper mediastinum as well as characteristic differences between the normal and pathologic picture. The typical features of the echocardiogram suggesting pulmonary sling, like the lack of the left pulmonary artery in its expected position, and the abnormal branching pattern of the right pulmonary artery were indicated. The greatest diagnostic difficulties in visualization of the abnormal route of the left pulmonary artery were related to the presence of air-containing tissues, like lungs and central airways between the ultrasound probe and area of interest. The other was the masking influence of the large patent arterial duct, that may mimic the left pulmonary artery arising from the pulmonary trunk. The other entities requiring differentiation with sling, like aplasia of the left lung, the direct or indirect aortic origin of the left pulmonary artery, were discussed. The role of other visualization technics, like computed 3D tomography, and magnetic nuclear resonance, as well as direct visualization of central airways with bronchoscopy in establishing precise diagnosis were stressed.