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

Abstract

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. 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. 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 mm2/m2 vs RVPA, 267±95 mm2/m2, p=0.2). After stage 2 palliation, oxygen saturation trended higher in the RVPA (81%±5%) vs MBT cohort (77%±8%, p<0.08). The Norwood operation using a RVPA nonvalved conduit is associated with improved branch PA growth.