Results of Palliation With an Initial Modified Blalock-Taussig Shunt in Neonates With Single Ventricle Anomalies Associated With Restrictive Pulmonary Blood Flow

Abstract

We report our current-era results after placement of a modified Blalock-Taussig shunt (mBTS) as the first surgery in the multistage palliation strategy of neonates born with single ventricle (SV) anomalies associated with restrictive pulmonary blood flow. Between 2002 and 2012, 174 neonates with SV underwent mBTS. Competing risks analysis modeled events after mBTS (death or transplantation, transition to Glenn) and subsequently after Glenn (death or transplantation, transition to Fontan) and examined risk factors affecting outcomes. Competing risks analysis showed that 2 years after mBTS 27% of patients had died or received transplantation and 73% had undergone Glenn. Five years after Glenn, 6% had died, 73% had undergone Fontan, and 21% were alive awaiting Fontan. Overall survival 8 years after mBTS was 68%. On multivariable analysis, risk factors for mortality were increased shunt size to weight ratio (hazard ratio [HR]:1.2 per 0.1 ratio increase [1.0 to 1.4], p = 0.015), postoperative extracorporeal membrane oxygenation (HR: 4.0 [2.2 to 7.4], p < 0.001), chromosomal and extracardiac malformations (HR: 2.5 [1.3 to 5.0], p = 0.008), cardiopulmonary bypass use (HR: 2.5 [1.3 to 4.5], p = 0.004), and underlying pulmonary atresia with intact ventricular septum (PAIVS) or atrial isomerism (HR: 2.1 [1.1 to 4.2], p = 0.035). Palliation outcomes with mBTS in SV patients trail behind the generally improved results of congenital heart surgery. Several anatomic and patient-related factors continue to affect survival. Mortality is high in low weight neonates in whom a balance between overcirculation due to large shunt and low pulmonary blood flow and risk of occlusion due to small shunt is difficult to attain. Patients with chromosomal and extracardiac malformations, atrial isomerism, and PAIVS continue to be the most challenging and are associated with higher hospital and interstage mortality.