The purpose of this trial is to determine, at 3 years of life, how the neurologic and functional outcomes in infants with single ventricles are different when comparing children treated with the Hybrid strategy to the Norwood strategy.
Neurologic deficits in children with single ventricle physiology are believed to be associated with the reconstruction of the aortic arch during the initial Norwood procedure as a neonate. In the last few years, a new management strategy (the 'Hybrid' strategy) has been proposed which defers the aortic arch reconstruction to a second stage procedure at 4-6 months of age. Proponents of the Hybrid strategy assert that the avoidance of cardiopulmonary bypass and circulatory arrest in the neonatal period will avoid neurologic injury in the critical neonatal period and thereby result in superior long-term neurologic outcomes. We are testing whether the Hybrid management strategy is associated with superior neurologic outcomes or not.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
50
Norwood palliation will be performed as per current clinical practice at The Hospital for Sick Children.
Hybrid palliation will be performed as per current clinical practice at The Hospital for Sick Children. The 'Hybrid' management strategy utilizes catheter-based and non-open heart surgical procedures in the neonatal period to stabilize the neonate.10 The majority of the reconstruction is thereby deferred to 4-6 months of age, at which time the second stage procedure including an aortic arch reconstruction is performed. The third stage procedure (Fontan) is identical between Norwood and Hybrid strategies.
The Hospital for Sick Children
Toronto, Ontario, Canada
RECRUITINGNeurologic and functional outcomes
Neurodevelopmental and functional status will be assessed at 14 months of age using the Bayley Scales of Infant Development®-Third Edition (BSID-III), MacArthur Commmunicative Development Inventory/Words and Gestures (CDI) and Functional Status-II-Revised Questionnaire.
Time frame: 14 months of age
Neurologic and functional outcomes
At \~3 years of age, the Vineland Scale,the Mullen Developmental Scale, and the BASC behavioural scale will be formally assessed
Time frame: 3 years of age (during procedure 3 pre-op)
Hemodynamic Assessment
Arterial, superior vena cava and pulmonary vein pressure will be monitored via indwelling catheters. This measurement will be taken during: procedure 1 pre-op, procedure 1 post-op, procedure 2 pre-op, and procedure 2 post-op.
Time frame: Baseline and 4-6 months
Blood Sampling
Standard blood gas samples will be drawn from indwelling arterial, SVC and pulmonary vein catheters to provide oxygen saturation and lactate data. This measurement will be taken immediately after chest opening, and then postoperatively at 2 hour intervals during the first 24 hours and at 4 hour intervals during the following 48 hours after first and second stage procedures.
Time frame: Baseline and 4-6 months
Systemic Oxygen Consumption
Measurement of pre- and post-operative VO2. This measurement will be taken during: procedure 1 pre-op, procedure 1 post-op, and procedure 2 pre-op
Time frame: Baseline and 4-6 months
Cerebral Oxygen Transport Surrogate Measurements
Cerebral oxygen saturation (ScO2) will be continuously measured by Near Infrared Spectroscopy (NIRS). This measurement will be taken during: procedure 1 pre-op, procedure 1 post-op, procedure 2 pre-op, and procedure 2 post-op.
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Time frame: Baseline and 4-6 months
Cerebral Blood Flow Velocity
Transcranial Doppler sonography using the TCD through the middle cerebral artery with a 2 MHz pulse-wave ultrasound transducer will be used to measure cerebral blood flow velocity non-invasively. This measurement will be taken during: procedure 1 pre-op, procedure 1 post-op, procedure 2 pre-op, and procedure 2 post-op.
Time frame: Baseline and 4-6 months
Electroencephalograph
Locked digital video electroencephalography (DVEEG) will be used to continuously monitor ischemic injury and seizures. This will be done at the folling times: procedure 1 pre-op, procedure 1 post-op prior to discharge, and procedure 2 post-op.
Time frame: Baseline and 4-6 months
MRI scans
Brain imaging will be assessed for evidence of congenital malformations or structural abnormalities, cerebral edema, acute ischemia, intracranial hemorrhages, periventricular leukomalacia (PVL), focal tissue loss, atrophy, delays in myelin maturation and infarcts. The MRI will be done during procedure 1 post-op prior to discharge, procedure 2 post-op prior to discharge and procedure 3 pre-op.
Time frame: Baseline, 4-6 months and 2-3 years