Right ventricle to pulmonary artery conduit improves outcome after stage I Norwood for hypoplastic left heart syndrome

Background - Diastolic run off into the pulmonary circulation and labile coronary perfusion are thought to contribute to morbidity and mortality after the Norwood procedure (NP). We compared outcomes from the use of a RV to PA conduit (RV/PA) or a modified Blalock-Taussig shunt (BTS), physiologically distinct sources of pulmonary blood flow. Methods and Results - Review of 56 consecutive patients who underwent a Norwood procedure with a RV/PA (n=36) or a BTS (n = 20) between 2000 and 2002. Median age was 4.5 days (range 1 to 40) and median weight was 3.1 kg (range 1.8 to 4.1). The RV/PA was constructed with a 5-mm conduit. Patients in the BTS group received a 4-mm shunt. Comparisons between RV/PA and BTS groups showed no difference for weight, gestational age, prenatal diagnosis, HLHS variant, associated diagnoses, ascending aortic size, ventricular function, AV valve function, and pulmonary venous obstruction. Operative survival was higher with RV/PA [33/36 (92%) versus 14/20 (70%); P=0.05]. Patients with RV/PA had less need for ventilatory manipulations to balance the Qp/Qs (1/36 v/s 8/20; P=0.001), delayed sternal closure (6/36 v/s 7/20; P=0.001), and extracorporeal support (5/36 v/s 7/20; P=0.036). RV/PA patients had more favorable postoperative hemodynamics: higher diastolic blood pressure without changes in systolic blood pressure at 1, 8, 24, 48 hours after the NP (46.3 v/s 39.5; 47.2 v/s 42.1; 46.1 v/s 37.1; and 47.1 v/s 40.2; all P = 0.001). Conclusion - RV/PA simplifies postoperative management and improves hospital survival after NP for HLHS.