Neurological Injury and Cerebral Blood Flow in Single Ventricles Throughout Staged Surgical Reconstruction

Abstract

Background Single ventricle patients experience a high rate of brain injury and adverse neurodevelopmental outcome, however, the incidence of brain abnormalities throughout surgical reconstruction and its relationship with cerebral blood flow, oxygen delivery and carbon dioxide reactivity remains unknown. Methods Single ventricle patients were studied with MRI scans immediately prior to bidirectional Glenn (pre-BDG), prior to Fontan and then 3–9 months after Fontan reconstruction. Results One hundred and sixty eight consecutive subjects recruited into the project underwent 235 scans: 63 pre-BDG (mean age 4.8+1.7 months), 118 BDG (2.9+1.4 years) and 54 after Fontan (2.4+1.0 years). Non-acute ischemic white matter changes on T2 weighted imaging, focal tissue loss, and ventriculomegaly were all more commonly detected in BDG and Fontans compared to pre-BDG (P<0.05). BDG patients has significantly higher CBF than Fontan patients. The odds of discovering brain injury adjusting for surgical stage as well as 2 or more co-existing lesions within a patient all decreased (63–75% and 44% respectively) with increasing amount of cerebral blood flow (P<0.05). In general, there was no association of oxygen delivery (with the exception of ventriculomegaly in the BDG group) or carbon dioxide reactivity with neurological injury. Conclusion Significant brain abnormalities are commonly present in single ventricle patients and detection of these lesions increase as children progress through staged surgical reconstruction with multiple co-existing lesions more common earlier than later. In addition, this study demonstrated that BDG patients had greater CBF than Fontan patients and that there exists an inverse association of various indices of CBF with these brain lesions, however, CO2 reactivity, oxygen delivery (with one exception) were not associated with brain lesion development.

Imaging of complications following Fontan circulation in children — diagnosis and surveillance

“…MR findings in later life show striking deviations from normal in most people, with focal and multifocal abnormalities of different degrees. Findings show that non-acute ischemic changes such as atrophy and ventriculomegaly accumulate with staged surgical reconstruction [ 80 ]. Typically, spreading white matter abnormalities have been associated with cognitive impairment as well as gray matter abnormalities [ 81 , 82 ].…”

Oxygen saturations and neurodevelopmental outcomes in single ventricle heart disease

“…Various predictors of neurodevelopmental outcomes in SVCHD have been established, including sociodemographic variables, disease characteristics, and aspects of the child's clinical course . One such clinical characteristic hypothesized to relate to subtle brain injury and associated neurodevelopmental abnormalities is the lower blood oxygen saturations that children with SVCHD experience from the prenatal period until the time of their Fontan operation and often, beyond . Hypoxemia is hypothesized to slow the pace of brain growth, particularly with regards to white matter, during gestation in SVCHD and contribute to increased inflammation and apoptosis as the brain develops during infancy, childhood, and adolescence .…”

“…[5][6][7] One such clinical characteristic hypothesized to relate to subtle brain injury and associated neurodevelopmental abnormalities is the lower blood oxygen saturations that children with SVCHD experience from the prenatal period until the time of their Fontan operation and often, beyond. 8 Hypoxemia is hypothesized to slow the pace of brain growth, particularly with regards to white matter, during gestation in SVCHD 9,10 and contribute to increased inflammation and apoptosis as the brain develops during infancy, childhood, and adolescence. 11 While hypoxemia during the stage-I palliation perioperative period has been shown to relate to poorer neurodevelopment in SVCHD [12][13][14] the unique contribution of chronic hypoxemia to altered neurodevelopment has been understudied in SVCHD.…”

Interrelationship Between Hemodynamics, Brain Volumes, and Outcome in Hypoplastic Left Heart Syndrome

“…One recent study examined cerebral blood flow throughout staged surgical reconstruction in single ventricle patients. The authors found that a higher cerebral blood flow correlated with a lower incidence of brain abnormalities [18].…”

“…It has been shown that neonates with HLHS display delayed brain development and neurologic abnormalities even before cardiac surgery [7], which may contribute to persistent white matter maturation delay and reduction found in our study patients at two to three years. Hypoxic conditions, intracerebral hemorrhages, strokes and inflammatory episodes during staged surgical reconstruction can further delay brain maturation [18]. Two major factors predispose the developing white matter and the subcortical gray matter to injury from hypoxia-ischemia [23].…”