Cardiac clinical trials

Brain Vascular Reactivity to Hypothermic Circulatory Arrest With Antegrade Cerebral Perfusion During Aortic Arch Surgery

Many neonates and infants who undergo complex cardiac surgery are affected by neurological developmental delays. Whilst catastrophic events are immediately identifiable from clinical examination or by macro changes on MRI or CT scans, smaller changes are often not immediately visible or detected. This is an observational pilot study examining brain vascular reaction to hypothermic circulatory arrest with antegrade cerebral perfusion and neuro-protection techniques during aortic arch surgery in neonates and infants. A combination of duplex ultrasound and transcranial doppler will be used to record in-depth information on the cerebrovascular changes that occur during the entire length of the surgical procedure and during the early postoperative period. The proposed techniques and equipment are non-invasive and are in use clinically to evaluate brain perfusion in a similar age group. During aortic arch surgery, the patient's body and brain temperature is reduced to values between 18 and 24 degrees centigrade in order to decrease metabolic demand that provides a form of metabolic protection. However, there is no consensus within the clinical community regarding the optimal temperature at which to perform surgery. Moreover, in order to improve cerebral perfusion, the brain is perfused via the right internal carotid artery with cold blood. At Alder Hey Children Hospital, this surgery is undertaken by the three surgeons but, due to clinical preference, differs in relation to the temperature at which surgery is undertaken. This provides the opportunity to observe the impact of different temperatures on cerebral vascular reactivity in neonates and young infants The arguments for future comparisons and a larger randomised study will be made based on the information gained from this observational study.