Development of the pulmonary arteries after the Norwood procedure: Comparison between Blalock-Taussig shunt and right ventricular-pulmonary artery conduit

Background. The Norwood-Sano procedure for hypoplastic left heart syndrome (HLHS) has been associated with improved postoperative hemodynamics and outcome. This study compared the effect of a Blalock-Taussig shunt with right ventricular-pulmonary artery (RV-PA) conduit before bidirectional Glenn on the development of the PAs. Methods. Between January 2000 and June 2007, 42 patients with HLHS underwent bidirectional Glenn: 19 (mean age, 7 +/- 1.5 months) had a Blalock-Taussig shunt (3.5 mm in 15; and 4 mm in 4); 23 patients (mean age, 5 +/- 1 month) had RV-PA conduit (5-mm tube). Patients underwent postoperative cardiac catheterization and echocardiograms. Results. Total PA (Nakata) index was 192 +/- 10 mm(2)/m(2) in the Blalock-Taussig group and 238 +/- 18 mm(2)/m(2) in the RV-PA conduit group (p = 0.03). In the RV-PA conduit patients, the left and right PAs had comparable diameters. In the Blalock-Taussig group, the left PA was smaller than the right (p = 0.02). The mean PA pressure at the end of the operation was 14 +/- 2 mm Hg in the Blalock-Taussig group and 11 +/- 1 mm Hg in the RV-PA conduit group (p = 0.06). Persistent pleural effusion occurred in 4 Blalock-Taussig patients (21%) and in 1 (4%) with RV-PA conduit (p < 0.05). Postoperative arterial oxygen saturation was 80% +/- 2% in the RV-PA conduit group and 74% +/- 2% in the Blalock-Taussig group (p < 0.05). Conclusions. The Norwood procedure with RV-PA conduit may have favorable effects on the development of the PA due to even distribution of pulmonary blood flow.