Preoperative cerebral blood flow is diminished in neonates with severe congenital heart defects.
OBJECTIVE
Impaired neurodevelopmental outcome represents a major morbidity for survivors of infant heart surgery for congenital heart defects. Previous studies in these neonates have reported preoperative microcephaly, periventricular leukomalacia, and other findings. The hypothesis of this study is that preoperative cerebral blood flow is substantially diminished and might relate to preoperative neurologic conditions.


METHODS
Preoperative brain magnetic resonance imaging was performed. Cerebral blood flow measurements in infants with congenital heart defects were obtained by using a novel noninvasive magnetic resonance imaging technique, pulsed arterial spin-label perfusion magnetic resonance imaging. Cerebral blood flow was measured before the operation under standard ventilation and repeated after increased carbon dioxide.


RESULTS
A total of 25 term infants were studied. The average age at the time of the operation was 4.4 +/- 4.6 days. Congenital heart defects varied widely. Microcephaly occurred in 24% (6/25). Baseline cerebral blood flow was 19.7 +/- 9.2 mL . 100 g -1 . min -1 (8.0-42.2 mL . 100 g -1 . min -1 ). Five patients had cerebral blood flow measurements of less than 10 mL . 100 g -1 . min -1 . Mean hypercarbic cerebral blood flow increased to 40.1 +/- 20.3 mL . 100 g -1 . min -1 (11.4-94.0 mL . 100 g -1 . min -1 , P < .001). Pairwise analyses found that low hemoglobin levels were associated with higher baseline cerebral blood flow values ( P = .04). Periventricular leukomalacia occurred in 28% (7/25) and was associated with decreased baseline cerebral blood flow values ( P = .05) and a smaller change in cerebral blood flow with hypercarbia ( P = .003).


CONCLUSIONS
Structural brain abnormalities are common in these neonates before surgical intervention. Preoperative cerebral blood flow for this cohort was low and drastically reduced in some patients. Low cerebral blood flow values were associated with periventricular leukomalacia. Carbon dioxide reactivity was preserved but might be compromised by some aspects of the cardiac anatomy. The full spectrum of cerebral blood flow measurements with this technique in congenital heart defects and their long-term significance require continued investigation.
Licht
Daniel J
DJ
Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Wood Building 6th Floor, 34th & Civic Center Boulevard, Philadelphia, PA 19104, USA. licht@email.chop.edu
Wang
Jiongjiong
J
Silvestre
David W
DW
Nicolson
Susan C
SC
Montenegro
Lisa M
LM
Wernovsky
Gil
G
Tabbutt
Sarah
S
Durning
Suzanne M
SM
Shera
David M
DM
Gaynor
J William
JW
Spray
Thomas L
TL
Clancy
Robert R
RR
Zimmerman
Robert A
RA
Detre
John A
JA
D001921:Brain / Q000098:blood supply / Q000503:physiopathology*; D005260:Female; D006330:Heart Defects, Congenital / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D006935:Hypercapnia / Q000150:complications; D007231:Infant, Newborn; D007969:Leukomalacia, Periventricular / Q000150:complications; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D010100:Oxygen / Q000097:blood; D012039:Regional Blood Flow
D010100:Oxygen