Hybrid Palliation for Infants With Critical Left Heart Obstruction

Quick Takes

  • Of 214 patients undergoing hybrid palliation, 60% had preoperative comorbidities including prematurity, low birth weight, or concomitant genetic syndromes.
  • 12-year survival for patients undergoing hybrid palliation was 55%.
  • At 5 years after hybrid palliation, 36% had completed Fontan, 35% had died, 12% had undergone transplantation, 9% had undergone biventricular repair, and 8% had not reached any of the other endpoints.

Study Questions:

What are patient characteristics and factors associated with subsequent outcomes for infants undergoing hybrid palliation for critical left heart obstruction (CLHO)?


A prospective multicenter trial was performed of patients enrolled within the Congenital Heart Surgeon’s Society CLHO cohort between 2005 and 2019. Multivariable hazard monitoring with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan completion, transplantation, or death.


A total of 214 patients were enrolled. Preoperative comorbidities including prematurity, low birthweight, and genetic syndrome were identified in 60% of infants undergoing hybrid palliation. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had undergone biventricular repair, 36% had completed Fontan, 12% had transplantation, 35% died, and 8% were alive without meeting one of the above endpoints. Independent factors associated with death were low birthweight, concomitant genetic syndrome, cardiopulmonary bypass during hybrid palliation, ≥ moderate tricuspid valve regurgitation, and smaller ascending aortic size.


The authors concluded that mortality remains high after hybrid palliation for infants with CLHO. Hybrid palliation may facilitate biventricular repair for some infants, and for others, may serve as stabilization for intended functional univentricular palliation or primary transplantation.


At many centers, hybrid palliation for infants with critical left heart obstruction is reserved for patients with high-risk features. In this study, 60% of enrolled infants had significant comorbidities including premature, low birthweight, and presence of a genetic syndrome. The outcomes could therefore be expected to be worse than the general population undergoing single ventricle palliation. Only 36% of patients undergoing hybrid palliation ultimately underwent Fontan completion, with 55% survival at 12 years. The need for bypass at the time of hybrid palliation was a risk for death, which was likely related to restrictive interatrial communication. The primary limitation of the study is heterogeneity and inter-institutional variability in the indications for hybrid palliation as opposed to conventional surgical palliation. However, this appears to be a representative sample of patients undergoing hybrid palliation and gives good information as to the intermediate-term outcomes of this complex and challenging population.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and CHD and Pediatrics, Cardiac Surgery and Heart Failure, Congenital Heart Disease, CHD and Pediatrics and Interventions, Heart Transplant, Interventions and Structural Heart Disease

Keywords: Fontan Procedure, Heart Defects, Congenital, Heart Transplantation, Hypoplastic Left Heart Syndrome, Infant

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