Children's Hospital of Wisconsin
Michael J. Danduran, Exercise Physiologist & Primary Investigator
Herma Heart Center
Milwaukee, WI
Research project: Near Infrared Spectroscopy (NIRS) as a Marker of Cerebral Perfusion in
Patients with and without Fenestration Following Surgical Fontan Palliation
Funding granted: $17,500
The goal of this investigation is to assess the regional cerebral saturation patterns in
patients with Fontan palliation during exercise with the focus of determining the impact of a
fenestration on cerebral perfusion patterns. This information may significantly impact the
clinical management of these patients and provide an enhanced understanding of the
physiologic coping mechanisms associated with stress allowing for improved participation
guidelines for recreational activities and an enhanced quality of life.
Patient’s who have a heart anatomy that consist of a single ventricle following a Fontan
repair will be asked to participate in this study. The investigators hope to identify how
oxygen gets delivered throughout the body, including the brain, muscles, and vital organs
allowing for an assessment of the heart’s ability to compensate during times of increased
work, which has been shown to decrease in this group of patients.
Exercise is a great tool for imposing stress to the human body. The work associated with
exercise causes the heart to beat faster, the lungs to work harder and the muscles to
contract more forcibly resulting in blood flow patterns that are very different than when a
body is at rest. These changes result in physical fatigue and in some cases exhaustion
leading to a person’s desire to stop what they are doing. The lungs, heart, and muscle work
in a continuous fashion to supply oxygen rich blood to and from the body while continuously
protecting the brain with enough oxygen. In a normal system, supply does not always meet
demand and in patients with imperfect anatomy such as congenital heart disease the
challenge is even greater. Patients with single ventricle anatomy must find ways to
compensate for limitations and the significance of these complications may result in altered
blood flow patterns throughout the body, the most important of which may be altered
oxygen flow to the brain.
The ability to measure the oxygen trends to the body and the brain can easily be made
through a machine called a Near Infrared Spectroscopy. It is non-invasive and it works
through a small 1x2 inch sticker placed on the patient while they walk on the treadmill.
These stickers have a red light that shines into the skin in the shape of a rainbow going
from one side of the sticker to the other. This light is absorbed into the body and using
mathematical formulas tells the investigators how much oxygen is in that tissue. For
parents of children with a congenital heart disease this is similar to the pulse oximeter (ET
light) that is used frequently during routine clinic visits but bigger.
The data that is obtained from the exercise test, in addition to the blood flow patterns
determined using the stickers described above, will provide the investigators with additional
information as to how patients with single ventricle anatomy accomplish and tolerate
stressful situations. More importantly, a focus on how the brain maintains its oxygen levels
would allow us a better understanding of the consequences of the different variations of the
Fontan repair. These differences include the presence of a small hole called a fenestration
that allows for blood that has lower oxygen levels to mix with oxygen rich blood. Finally, the
results of this investigation will provide the clinicians with valuable information that may
benefit the long-term management of patients with a single ventricle.
