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Dr Gregory King

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Dr Gregory King

Valve function in children with half a heart

Dr Gregory King, Murdoch Children's Research Institute

2019 Health Professional Scholarship

Years funded: 2020-2023

Atrioventricular valve regurgitation is a risk factor for poor outcomes during Fontan palliation. My recent work has shown that approximately one third of Fontan patients will experience moderate or greater regurgitation or require valve intervention by 30 years of age and this number increases to 50% by 45 years of age. I have shown that atrioventricular valve failure increases the rates of Fontan failure (death, heart transplant, Fontan re-operation, disability) over two-fold compared to patients with a competent valve. Of concern, the current surgical methods of valve repair are resulting in poor outcomes. Up to 50% of patients undergoing valve repair will have recurrent regurgitation or require a second valve operation within 5 years of their initial repair.

This is occurring as more patients are undergoing Fontan palliation and the long-term survival following Fontan continues to improve. As such, the size of the single ventricle population is expected to double over the next 20 years, with an increase in the average age of patients from 18 to 35 years. It has become clear that atrioventricular valve failure will create a large burden of morbidity and mortality in an increasing population of single ventricle adults. As it stands, valve failure appears to be the most important modifiable target to improve the long-term outcomes of these patients. My research project aims to improve our understanding of atrioventricular valve failure and to determine the optimal management strategies for patients with a functional single ventricle.

There is limited data assessing the accuracy of echocardiography in the measurement of regurgitation in single ventricle patients. I will perform a study correlating the degree of regurgitation as measured by cardiac MRI with echocardiography. I will assess the outcomes of different valve repair techniques when used for management of different aetiologies of regurgitation. This will help to determine if there are subgroups of patients with valve regurgitation that are amenable to valve repair and if there are others that should proceed directly to valve replacement. Given that valve repair after Fontan is associated with a significant peri-operative mortality, I will determine a risk stratification score for use in clinical decision-making settings to decide which patients with regurgitation after Fontan should undergo valve intervention and which should be managed conservatively.

Last updated12 July 2021