Cerebral Blood Flow Following Hybrid Stage I Palliation in Infants with Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) palliation may result in altered cerebral blood flow with subsequent neurodevelopmental implications. The purpose of the study was to assess blood flow in the middle cerebral artery (MCA) and investigate the relationship with early neurodevelopmental outcomes in infants with HLHS after hybrid stage I. Transcranial Doppler (TCD) was performed to obtain peak systolic, end-diastolic, and mean velocities, as well as pulsatility index of the MCA in infants with HLHS (n = 18) at baseline and at 2, 4, and 6 months of age. Developmental assessment was performed at 6 months of age. Results of TCD and development were compared to healthy control subjects (n = 6) and normative data. Overall, peak systolic velocity (p = 0.0031), end-diastolic velocity (p < 0.0001), and mean velocity (p < 0.0001) were significantly lower and pulsatility index (p = 0.0011) significantly higher in the HLHS group compared to the control group. A significant increase in change over time was noted for peak systolic velocity (p < 0.0016) and mean velocity (p < 0.0046). There was no significant correlation between TCD variables and development scores. TCD values in 5-6 months old infants with HLHS who undergo hybrid stage I palliation had consistently lower blood flow velocities than control infants; however, pulsatility index was slightly higher. No correlation between TCD measurements and measures of cognitive, language, and motor skills were noted.