Diagnosis:
There are two diagnostic goals in LPAS - firstly to identify the
retrotracheal aberrant LPA arising from the RPA and secondly to
establish the degree of airway compromise and stenosis and if they are
complete tracheal rings. The former can be reliably ascertained with
echocardiography showing the main pulmonary artery extending directly to
the right pulmonary artery, and the left pulmonary artery arising from
the right pulmonary artery (figure 4). Other intracardiac lesions may
also be identified by echocardiography.