175. ACHD: Single Ventricle Circulation and Fontan Palliation with Dr. Yuli Kim

CardioNerds (Amit Goyal and Daniel Ambinder), ACHD series co-chair Dr. Daniel Clark (Vanderbilt University), and ACHD FIT lead Dr. Danielle Massarella (Toronto University Health Network) join ACHD expert Dr. Yuli Kim (Associated Professor of Medicine & Pediatrics at the University of Pennsylvania), to discuss single ventricular heart disease and Fontan palliation. They cover the varied anatomical conditions that can require 3-step surgical palliation culminating in the Fontan circulation, which is characterized by passive pulmonary blood flow, high venous pressures, and low cardiac output. Audio editing by Dr. Gurleen Kaur (Director of the CardioNerds Internship and CardioNerds Academy Fellow). 

The CardioNerds Adult Congenital Heart Disease (ACHD) series provides a comprehensive curriculum to dive deep into the labyrinthine world of congenital heart disease with the aim of empowering every CardioNerd to help improve the lives of people living with congenital heart disease. This series is multi-institutional collaborative project made possible by contributions of stellar fellow leads and expert faculty from several programs, led by series co-chairs, Dr. Josh Saef, Dr. Agnes Koczo, and Dr. Dan Clark.

The CardioNerds Adult Congenital Heart Disease Series is developed in collaboration with the Adult Congenital Heart Association, The CHiP Network, and Heart University. See more

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Pearls • Notes • References • Guest Profiles • Production Team

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Pearls

There are various forms of unpalliated ‘single ventricle’ congenital heart disease. The three main hemodynamic issues that need to be addressed in any form are unbalanced flow, pulmonary over-circulation, and blood mixing. 

The Fontan palliation is a series of operations for congenital heart disease patients in whom biventricular repair is not feasible. 

In the completed Fontan circulation, systemic venous blood is surgically routed directly to the lungs, effectively bypassing the heart, and creating passive pulmonary blood flow. 

The hallmarks of the Fontan circulation (and Fontan failure) are elevated central venous pressure and low cardiac output. 

Patients with Fontan circulation may experience significant morbidity in the long term from both cardiac and non-cardiac sequelae, and require lifelong specialist care. 

Show notes

1. Why do some patients require Fontan palliation? 

Many different types of anatomies may ultimately require single ventricular palliation via the Fontan procedure due to inadequate biventricular function to support both pulmonary and systemic circulations. Some examples include Tricuspid Atresia (hypoplastic RV), Double Inlet Left Ventricle (DILV; hypoplastic RV), Hypoplastic Left Heart Syndrome (HLHS; hypoplastic LV), and atrioventricular septal defects (AVSD; either RV or LV may be inadequate based on “commitment” of the common AV valve). The Fontan procedure was first described in 1971; at this time, mortality of single ventricular patients exceeded 90% in the first year of life. 

2. What are the stages of Fontan palliation? 

Effective pulmonary blood flow/balancing flow to the pulmonary and systemic circulations: for many conditions, this involves retrograde pulmonary blood flow from a systemic -> PA shunt (i.e. Blalock-Taussig-Thomas “BTT” shunt in which the subclavian artery is turned down and anastomosed to the pulmonary artery). In infants, the pulmonary vascular resistance (PVR) is high perinatally and gradually lowers over the first 3 months of life to adult levels with exposure to the atmosphere’s natural pulmonary vasodilator: oxygen. Thus, in the first 3 months of life babies have an intri...