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(HealthNewsDigest.com) – DALLAS, April 25, 2012 — A new monitoring method and blood test may provide early warnings when a child’s brain isn’t getting enough blood during heart surgery, according to new research presented during the American Heart
Association’s Emerging Science Series webinar.
Brain injury occurs in 30 percent to 70 percent of infants and children
undergoing repair of congenital heart defects. A congenital heart defect is a heart abnormality present at birth. Out of 1,000 live births in the United States, about 8 babies will have some kind of heart defect.
Previously, there has been no way to detect brain injury during surgery
as it happens. This research was a multi-center observational pilot
study to evaluate the feasibility of new monitoring strategies in a
high-risk population of children with congenital heart disease.
Unlike other organs, the brain can automatically adjust blood vessel
size to keep blood flow constant when blood pressure changes.
Researchers developed the “hemoglobin volume index,” a non-invasive
monitoring technique to assess changes in the brain arteries. This monitoring technique allowed them to determine the lowest pressure before automatic adjustment was compromised.
Researchers compared patient blood pressures with blood levels of glial fibrillary acidic protein (GFAP), an indicator of brain damage.
In 61 children (aged one week to 17 years) undergoing heart repair
surgery, researchers found that:
— A lower limit of pressure autoregulation or LLA could be identified in
85 percent of the children and varied widely between patients; meaning
that 85 percent are at risk of brain hypoperfusion.
— Both the hemoglobin volume index and GFAP became abnormal when the
childrens’ heart and lung function was taken over by cardiopulmonary
bypass during surgery, with the worst readings during rewarming,
indicating the period of highest risk for the child undergoing heart
surgery;
— The more time spent below LLA was associated with some increase in GFAP,
suggesting a link between periods of decreased blood flow autoregulation
and decreased brain blood flow and brain injury.
“Because the autoregulatory changes occurred almost concurrently with
signs of brain injury, we may have a real-time measure where we can
detect when injury is occurring and modify how we are managing the
patients, for example being more aggressive with controlling blood
pressure,” said R. Blaine Easley, M.D., lead author and associate
professor in anesthesiology and pediatrics at Baylor college of
Medicine in Houston.
The next step is a multi-center study that will correlate intra-operative test results with MRI changes and neurodevelopmental outcomes in the 18 months after surgery.
Co-authors are Jacky Jennings, Ph.D., M.D.; Kathleen Kibler, B.S.;
Kenneth M. Brady, M.D.; Brittany Serratos, B.S.; Dean B. Andropoulos,
M.D.; Marissa Brunetti, M.D.; Eugenie Heitmiller, M.D.; Jennifer K.
Lee, M.D.; Michael Smith, B.S.; Pratima Dulloor, B.S.; Bradley S.
Marino, M.D., M.P.P.; James Spaeth, M.D.; and Allen D. Everett, M.D.
Author disclosures are on the manuscript.
The study is funded in part by an American Heart Association clinical
research program grant from the Southwest affiliate.
For more about congenital heart defects visit
heart.org/congenitalheartdefects.
Statements and conclusions of study authors published in American Heart
Association scientific journals or presented at American Heart
Association conferences are solely those of the study authors and do
not necessarily reflect the association’s policy or position. The
association makes no representation or guarantee as to their accuracy
or reliability. The association receives funding primarily from
individuals; foundations and corporations (including pharmaceutical,
device manufacturers and other companies) also make donations and fund
specific association programs and events. The association has strict
policies to prevent these relationships from influencing the science
content. Revenues from pharmaceutical and device corporations are
available at www.heart.org/corporatefunding.
NR12 — 1063 (ESS/Easley)
Additional resources are available on the right column of this link:
http://newsroom.heart.org/pr/aha/_prv-new-tests-monitor-brain-health-23
2270.aspx
heart.org and strokeassociation.org
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