Brain immaturity is associated with brain injury before and after neonatal cardiac surgery with high-flow bypass and cerebral oxygenation monitoring.
BACKGROUND
New intraparenchymal brain injury on magnetic resonance imaging is observed in 36% to 73% of neonates after cardiac surgery with cardiopulmonary bypass. Brain immaturity in this population is common. We performed brain magnetic resonance imaging before and after neonatal cardiac surgery, using a high-flow cardiopulmonary bypass protocol, hypothesizing that brain injury on magnetic resonance imaging would be associated with brain immaturity.


METHODS
Cardiopulmonary bypass protocol included 150 mL . kg(-1) . min(-1) flows, pH stat management, hematocrit > 30%, and high-flow antegrade cerebral perfusion. Regional brain oxygen saturation was monitored, with a treatment protocol for regional brain oxygen saturation < 50%. Brain magnetic resonance imaging, consisting of T1-, T2-, and diffusion-weighted imaging, and magnetic resonance spectroscopy were performed preoperatively, 7 days postoperatively, and at age 3 to 6 months.


RESULTS
Twenty-four of 67 patients (36%) had new postoperative white matter injury, infarction, or hemorrhage, and 16% had new white matter injury. Associations with preoperative brain injury included low brain maturity score (P = .002). Postoperative white matter injury was associated with single-ventricle diagnosis (P = .02), preoperative white matter injury (P < .001), and low brain maturity score (P = .05). Low brain maturity score was also associated with more severe postoperative brain injury (P = .01). Forty-five patients had a third scan, with a 27% incidence of new minor lesions, but 58% of previous lesions had partially or completely resolved.


CONCLUSIONS
We observed a significant incidence of both pre- and postoperative magnetic resonance imaging abnormality and an association with brain immaturity. Many lesions resolved in the first 6 months after surgery. Timing of delivery and surgery with bypass could affect the risk of brain injury.
Andropoulos
Dean B
DB
Department of Anesthesiology, Baylor College of Medicine, Division of Pediatric Cardiovascular Anesthesiology, Texas Children's Hospital, 6621 Fannin, WT 17417B, Houston, TX 77030, USA. dra@bcm.tmc.edu
Hunter
Jill V
JV
Nelson
David P
DP
Stayer
Stephen A
SA
Stark
Ann R
AR
McKenzie
E Dean
ED
Heinle
Jeffrey S
JS
Graves
Daniel E
DE
Fraser
Charles D
CD
D001921:Brain / Q000254:growth & development; D001927:Brain Diseases / Q000175:diagnosis / Q000209:etiology* / Q000378:metabolism; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002315:Cardiopulmonary Bypass / Q000009:adverse effects*; D006801:Humans; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000378:metabolism; D011446:Prospective Studies
D010100:Oxygen