Comparison of hemodynamics between Norwood procedure and systemic-to-pulmonary artery shunt for single right ventricle patients

Abstract

Despite that surgical outcomes of patients with hypoplastic left heart syndrome have improved, one of the problems remaining is the high interstage mortality after a stage I Norwood procedure. The purpose of this study was to determine the hemodynamic characteristics of hypoplastic left heart syndrome after a Norwood procedure. We examined the perioperative hemodynamic differences of the staged operation between the first stage of the Norwood procedure and systemic pulmonary shunt for single right ventricle patients. Data from 39 patients who underwent a Norwood procedure (right ventricle to pulmonary artery conduit: 19, Blalock-Taussig shunt, 20) were analyzed. There were nine early and seven interstage deaths. Bidirectional cavopulmonary shunt was performed in 15 patients and the Fontan procedure in 9 (group H). We defined the control group as 26 patients who underwent the first stage of a systemic pulmonary shunt for a single ventricle. Bidirectional cavopulmonary shunt was performed in 14 patients and the Fontan procedure in 8 (group C). We compared the perioperative hemodynamics of the staged operation between the two groups. Cardiothoracic ratio and single ventricular diastolic dimension before bidirectional cavopulmonary shunt were acutely increased in group H (P=0.02, <0.001). There was no significant difference between the two different types of Norwood procedures. The pulmonary artery index for the right heart bypass operation was lower in group H than in group C (P<0.001). Oxygen saturation before bidirectional cavopulmonary shunt in group H decreased (P<0.001) and thus was lower than that in group C (P=0.003). Mortality and the postoperative clinical parameters of the right heart bypass operation were not different between the two groups. Patients with hypoplastic left heart syndrome showed hemodynamic instability of acutely increased cardiothoracic ratio, and single ventricular diastolic dimension despite decreased oxygen saturation interstage after stage I of a Norwood procedure. This suggests that this hemodynamic characteristics in hypoplastic left heart syndrome correlates with the higher mortality before second stage palliation than in found with single right ventricle patients.