Brain MRI Injury Before and After Neonatal Cardiac Surgery With High-Flow Bypass and Maximized Oxygen Delivery Strategy

  • Dr Dean Andropoulos, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr Jill Hunter, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr David Nelson, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr Stephen Stayer, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr Ann Stark, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr Emmitt McKenzie, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr Jeffrey Heinle, Texas Children's Hospital/Baylor College of Medicine, United States
  • Dr Charles Fraser, Texas Children's Hospital/Baylor College of Medicine, United States

    • Introduction: New intraparenchymal brain injury on MRI, consisting of white matter injury (WMI), infarction, or intraparenchymal hemorrhage, is observed in 36-73% of neonates after cardiac surgery with CPB.(1-3) We performed brain MRI before and after neonatal cardiac surgery, using a high flow CPB protocol, with the hypothesis that incidence of brain injury would be reduced compared to previous studies, and to establish a baseline incidence for neuroprotection studies.

    Methods: CPB protocol included 150 ml/kg/min flows, pH stat management, hematocrit >30%, and high flow antegrade cerebral perfusion.(4) Regional brain oxygen saturation (rSO2) <50% was treated by protocol. Brain MRI was performed preoperatively, 7 days postoperatively, and at age 3-6 months.

    Results: 24 of 67 patients (36%) had new postoperative WMI, infarction, or hemorrhage, and 15% had new WMI. (Figure 1). Associations with new postoperative injury included preoperative brain injury (p<0.001), and low brain maturity score (p=0.05). 45 patients had a 3rd scan, with 27% incidence of new lesions; 58% of previous lesions partially or completely resolved.

    Discussion: Despite evidence-based strategy to maximize brain oxygen delivery, and a reduction in incidence of new injury and WMI compared to previous reports, there is a significant incidence of both pre- and postoperative MRI abnormality in this population. Some lesions resolve in the first 6 months after surgery. Novel perioperative neuroprotective strategies are needed to assess whether long term improvement in neurodevelopmental outcomes can be achieved.

    References: 1. Stroke 2007;38:736; 2.J Thorac Cardiovasc Surg 2006;131:190; 3. Circulation 2002;106[suppl I] I-109; 4.Pediatr Card Surg Annu. 2008:61