Discussion
APVS includes rudimentary, dysplastic, or absent pulmonary valve leaflets, dilated main pulmonary artery with or without dilation of its branches, to-and-fro flow at the site of the absent pulmonary valve, and systolic pressure gradient across the narrowed pulmonary valve1. APVS is a rare variant of ToF, which accounts for approximately 3–6% of patients with ToF 2.
L-TGA is also rare, with a published incidence ranging from 0.02 to 0.07 per 1000 births 3. The most common anatomic cardiac abnormalities with L-TGA include ventricular septal defect, pulmonary stenosis, and abnormalities of the tricuspid valve 3.
A dilated pulmonary artery with APVS can compress the tracheobronchial tree and the esophagus, which is a significant indicator of poor postnatal prognosis 4. One study showed that complete repair with a valved conduit and reduction pulmonary arterioplasty can help improve tracheomalacia 5. Although most patients might require pulmonary arterioplasty, it is still controversial whether a pulmonary valve or a valved/unvalved conduit should be inserted and how the degree of size reduction of the pulmonary artery should be determined. The standard medical therapy for tracheomalacia is positive-pressure ventilation with or without a tracheostomy5. We performed anatomical left ventricle to pulmonary artery shunt with a bicuspid conduit made of polytetrafluoroethylene, which has excellent biocompatibility and low antigenicity6. Our patient required tracheostomy and positive pressure ventilation from birth till the age of one year. The anatomical left ventricle instead of the right ejected blood to the pulmonary artery directly because of cTGA. This, along with aortic valve stenosis, could lead to pulmonary over circulation and dilate the pulmonary artery easily. Therefore, the complex of APVS, cTGA, and aortic stenosis might cause pulmonary artery dilation and tracheomalacia more easily than APVS with TOF.