Case Report
An eight months old male child weighing 4.5 Kg presented with complains of breathlessness, repeated respiratory tract infections and failure to thrive. The child was malnourished and had tachycardia and tachyopnea. He had mild cyanosis with an oxygen saturation of 85% on room air. An ejection systolic murmur was heard over the pulmonary area on auscultation. Chest radiogram revealed cardiomegaly and differential pulmonary vascularity with features of increased pulmonary blood flow on the right lung field. The electrocardiogram suggested bi-ventricular hypertrophy. Echocardiogram examination revealed anomalous origin of right pulmonary artery (AORPA) from ascending aorta and hypoplastic pulmonary annulus. The main pulmonary artery (MPA) continued as left pulmonary artery. The interatrial septum was intact and there was a large mal-aligned ventricular septal defect. The obstruction in the right ventricular outflow tract was predominantly deemed to be valvular. A decision to disconnect right pulmonary artery (RPA) from aorta and create pulmonary confluence, close the VSD and enlarge the pulmonary outflow was made.
Surgical approach was median sternotomy. During intra-operative inspection, the pulmonary annulus was found to be severely hypoplastic and a large coronary artery was found crossing the pulmonary annulus. (Figure 1) It was a branch from right coronary artery crossing the right ventricular outflow tract and running parallel to the inter-ventricular groove as an accessory left anterior descending artery (LAD). Pulmonary arteries were extensively mobilised upto the lobar branches.. Cardiopulmonary bypass was initiated after aorto-bicaval cannulation. RPA was snared immediately prior to initiation of CPB. The ligamentum ductus was divided. Del Nido’s Cardioplegia at 30ml/ Kg was administered to achieve cardiac arrest. RPA was disconnected from the side of aorta. Defect in the aorta was sutured primarily in two layers. RPA was anastomosed to MPA directly and pulmonary confluence was created. The ventricular septal defect (VSD) was routed to aorta using bovine pericardial patch. MPA was opened longitudinally without cutting across the pulmonary annulus in order to preserve the anomalous coronary artery. A tri-leaflet valved conduit was created using bovine pericardium (St. Jude Medical) and 0.1 mm Polytetrafluoroethylene (Gore-Tex, WL Gore and Associates Inc, Flagstaff, Ariz). The valve leaflets are created with 0.1mm PTFE membrane which is sutured to a sheet of bovine pericardium. The bovine pericardial sheet is rolled into a tube to make the valved conduit. The internal diameter of the conduit was 12mm and it was interposed between the right ventricle and MPA. (Figure 2) The native right ventricular outflow tract was also preserved making a double barrel right ventricle outflow tract. The postoperative course was uneventful. The child was weaned from mechanical ventilation and extubated after 48 hours and was discharged on sixth postoperative day. The child is asymptomatic at 36 months after surgery. The native pulmonary valve has grown from 6 mm to 8 mm in diameter and the RV to PA conduit is functioning well with mild regurgitation.