Right ventricle to pulmonary artery conduit has a favorable impact on postoperative physiology after Stage I Norwood: Preliminary results

Objective: Although significant progress has been made in the perioperative management of neonates with hypoplastic left heart syndrome (HLHS), early survival has plateaued. Moreover, low but important interstage mortality remains unsolved. With a systemic to pulmonary artery shunt, the combination of significant diastolic runoff into the pulmonary circulation, a large volume load on the single ventricle and precarious coronary perfusion result in a delicate physiologic state. In order to minimize these detrimental features, a right ventricle to pulmonary artery (RV to PA) conduit was used as the source of pulmonary blood flow in patients undergoing Stage I Norwood for HLHS. Methods: Prospective data collection in 15 consecutive patients who underwent Stage I Norwood with an RV to PA conduit. Results: Mean age at surgery was 2.5±2 days (range 1-8), mean weight was 2.9±0.3 kg (range 2.2-3.6) and mean gestational age was 37 weeks (range 35-40). Anatomic diagnosis was HLHS in all patients, aortic atresia was present in ten. Mean ascending aortic size was 2.9±0.9 mm (range 1.5-5). Two patients had moderate atrioventricular valve regurgitation and a genetic syndrome and/or congenital anomaly was present in five patients. Thirteen patients received a 5-mm polytetrafluoroethylene RV to PA conduit, and a 4-mm conduit was used in two. Mean circulatory arrest time was 55±6 min. Postoperatively, mean diastolic blood pressure at 1, 8 and 24 h were 47±7, 46±3 and 43±6 mmHg, respectively. Median time to extubation was 23 h (range 9-96) and was less than 24 h in ten patients. Median intensive care unit and hospital stay were 5 days (range 2-19) and 10 days (6-22), respectively. Early mortality was 1/15 (6%). At a mean follow-up of 10.8±3.4 months, 12 patients underwent stage II, and three patient have completed the Fontan. Conclusion: RV to PA conduit eliminated diastolic runoff into the pulmonary vascular bed resulting in a higher diastolic blood pressure. This physiology appears to be associated with a more stable postoperative course and improved hospital survival.