Neurologic sequelae of open-heart surgery in children. An 'irritating question'

As pediatric cardiac surgical techniques have improved in recent years, mortality rates have dropped and attention has turned to residual morbidity, especially neurologic sequelae. Although the majority of children undergoing open-heart surgery for correction of congenital heart defects apparently emerge with no adverse consequences, a small percentage suffer permanent neurologic injury (seizures, motor disorders). Another small and not well-defined population may be left with disorders of higher cortical function, such as mental retardation or learning disabilities. A survey of six major pediatric cardiac surgery units in North America was undertaken in 1988-1989 to ascertain current approaches to the detection and management of neurologic sequelae of pediatric open-heart surgery. All units reported seeing a small but definite incidence of postoperative neurologic symptoms, including alterations of consciousness, seizures, and localized abnormalities such as hemiparesis or delayed choreoathetoid syndromes. Postoperative neuroimaging procedures have shown a disturbing incidence of hypoxic-ischemic encephalopathy, unsuspected cerebral atrophy, and subdural hematomas. Pathogenesis may include factors related to preoperative brain anomalies and/or hypoxic insults, altered cerebral blood flow and metabolism during hypothermic cardiopulmonary bypass with or without total circulatory arrest, embolization, and low cardiac output states postoperatively. Further studies are needed to examine the mechanisms of injury and to develop techniques to minimize the occurrence of these sequelae, as they may be associated with life-long neurologic disability and reduced quality of life.