The purpose of this study is to compare the liver stiffness, which can be caused by
congestion and fibrosis in pediatric patients before and after a Fontan heart operation.
A new form of ultrasound elastography (Acoustic Radiation Force Impulse, or ARFI) will
measure liver stiffness.
The Fontan repair for single ventricle congenital heart lesions consists of three stages.
This surgery has enable pediatric patients who have the repair to live into adulthood.
Stage 3 of the surgery introduces immediate congestion of blood in the liver by increasing
central venous pressure (CVP). CVP is the blood pressure within the vena cava, a major blood
vessel in the body.
Many patients later develop progressive liver fibrosis (stiffness) possibly as a result of
increased blood pressure. Liver stiffness is increased both by congestion and fibrosis.
Liver fibrosis has significant health risks and may complicate the patient's future
There are no established, noninvasive means of detecting the liver fibrosis until it becomes
severe. Acoustic radiation force impulse (ARFI) elastography, an ultrasound technique, can
measure the stiffness of the liver safely from outside the body.
The investigators hypothesize that liver stiffness will be increased by stage 3 of the Fontan
operation due to onset of liver congestion.
Using ARFI, the investigators will measure liver stiffness before and immediately after stage
3 of the Fontan operation, when congestion of blood is likely the only contributor to any
change in liver stiffness.
The investigators will follow the trend of liver stiffness at six months by repeating the
- Pediatric patients ages 0-17
- Patients presenting to the University of Michigan for evaluation just before
undergoing stage 3 of the Fontan operation
- Patients over the age of 17
- Patients who have chronic liver disease (elevation of ALT, AST, or Bilirubin greater
than two times the upper limits of normal >4 weeks)
- Patients who have evidence of liver enlargement or nodularity on prior ultrasound
- Patients who have a history of portal vein or hepatic vein thrombosis
- Patients (parents) who are unwilling to read and sign the informed consent document