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Subaortic obstruction and the Fontan operation
1Department of Pediatrics, The Hospital for Sick Children, University of Toronto Faculty of Medicine, Ontario, Canada.
Insights
Systemic outflow tract obstruction is a risk factor for poor outcomes in single ventricle heart patients undergoing the Fontan procedure. Surgical strategies like bidirectional cavopulmonary connection have effectively managed this obstruction.
Area of Science:
- Cardiology
- Pediatric Cardiology
- Congenital Heart Disease
Background:
- Systemic outflow tract obstruction (SOOTO) in single ventricle physiology is linked to myocardial hypertrophy and adverse outcomes after the Fontan procedure.
- SOOTO can be congenital or acquired, with acquired forms influenced by factors like ventricular septal defect size and prior surgeries in complex congenital heart defects.
Purpose of the Study:
- To analyze the contributing factors to acquired systemic outflow tract obstruction in patients with specific complex heart conditions.
- To evaluate the effectiveness of surgical staging in mitigating the risks associated with SOOTO in this population.
Main Methods:
- Review of clinical data and surgical histories of patients with double-inlet left ventricle, rudimentary right ventricle, and discordant ventriculoarterial connection.
- Analysis of the impact of interventions such as bidirectional cavopulmonary connection and ventricular septal defect enlargement on SOOTO.
Main Results:
- Identified ventricular septal defect size, pulmonary artery banding, and volume unloading procedures as key contributors to acquired SOOTO.
- Demonstrated that staged surgical approaches, including bidirectional cavopulmonary connection and VSD enlargement, have successfully addressed this obstructive factor.
Conclusions:
- Acquired systemic outflow tract obstruction is a significant concern in complex single ventricle heart disease.
- Staged surgical management provides an effective strategy to neutralize the negative impact of SOOTO, improving outcomes for Fontan procedure candidates.
Abstract:
Systemic outflow tract obstruction in the heart with a functional single ventricle promotes myocardial hypertrophy, and this has been shown to be an unequivocal risk factor for poor outcome at Fontan procedure. Such systemic outflow tract obstruction may be congenital or acquired. Those factors contributing to acquired systemic outflow tract obstruction in those patients with a double-inlet left ventricle, a rudimentary right ventricle, and a discordant ventriculoarterial connection include the size of the ventricular septal defect, previous pulmonary artery banding, and other volume unloading surgical procedures. Staging with a bidirectional cavopulmonary connection and construction of a proximal pulmonary artery-aortic connection or ventricular septal defect enlargement has neutralized this factor.