A Comparison of the Modified Blalock-Taussig Shunt With the Right Ventricle-to-Pulmonary Artery Conduit

Background. This study compared the modified Blalock-Taussig (MBT) shunt with the right ventricle-to-pulmonary artery (RVPA) conduit with respect to outcome and PA growth. Methods. PA growth was assessed in 19 MBT patients and in 15 RVPA patients before stage 2 palliation for hypoplastic left heart syndrome. The RVPA was done with a ringed Gore-Tex tube (W. L. Gore and Assoc, Flagstaff, AZ) at each anastomosis. Results. The two cohorts had similar pre-Glenn demographic and hemodynamic data. No patient required transcatheter or surgical intervention on the shunt or PAs after stage 1 palliation. The branch PA growth was better in RVPA (McGoon ratio: MBT, 1.5 +/- 0.2 vs RVPA, 2.0 +/- 0.6; p < 0.003) and was significantly more balanced (right-to-left PA area ratio: MBT, 1.5 +/- 0.5 vs RVPA, 0.9 +/- 0.6; p = 0.002). The Nakata index trended higher in RVPA (MBT, 242A +/- 90 mm(2)/m(2) vs RVPA, 267 +/- 95 mm(2)/ m(2), p = 0.2). After stage 2 palliation, oxygen saturation trended higher in the RVPA (81% +/- 5%) vs MBT cohort (77% +/- 8%, p < 0.08). Conclusions. The Norwood operation using a RVPA nonvalved conduit is associated with improved branch PA growth. (Ann Thorac Surg 2011; 91: 1479-85) (C) 2011 by The Society of Thoracic Surgeons