The mortality for congenital heart surgery is now so low that the focus has shifted to improving the quality of life for children after heart surgery. Neurodevelopmental deficit is the most important surgical morbidity in congenital heart disease. This review article describes both clinical and laboratory studies in this area, most of which were performed at Children's Hospital Boston over the last 15 years. An epidemic of choreoathetosis at Children's Hospital in the late 1980s was the initial stimulus for studies of neurological injury after congenital heart surgery. A high index of suspicion associated the epidemic with a change in pH strategy from the more acidotic pH stat strategy to the alpha stat strategy during cardiopulmonary bypass. A more alkaline pH like alpha stat results in a shift in the oxyhemoglobin dissociation curve to the left, i.e. tighter binding of oxygen with hemoglobin. Other potential factors that limit cerebral oxygen delivery during cardiopulmonary bypass include reduced perfusion flow rate of the cardiopulmonary bypass pump, a significant reduction in oxygen delivery secondary to hemodilution, a shift to the left of oxyhemoglobin dissociation secondary to hypothermic blood temperature, and run off from the systemic circulation to the pulmonary circulation through collaterals and bronchial vessels. In addition venous cannulation in neonates and young infants can be tenuous. The fact that young children are free of arteriosclerosis potentially makes them an ideal population for studying the effects of cardiopulmonary bypass on neurodevelopmental outcome. On the other hand the heterogeneity of congenital heart defects as well as genetic associations such as microdeletion of chromosome 22 can complicate the interpretation of clinical studies in neurodevelopmental outcome after cardiac surgery. The results of several prospective and retrospective studies of neurological and developmental outcome after pediatric cardiac surgery as well as laboratory studies have led us to the following inferences: 1) the use of circulatory arrest should be minimized; 2) pH stat strategy is preferred for infant cardiopulmonary bypass over the alpha stat strategy; 3) a higher hematocrit, e.g. 30% may be preferable to 20%; 4) a hyperoxic perfusion strategy is preferred over a normoxic strategy; and 5) postoperative fever should be strenuously avoided.

Hypertrophic cardiomyopathy is manifest by interesting pathophysiology. Understanding these mechanisms and roles of current therapeutic modalities is the key to successful treatment of symptomatic patients. There is now a diverse armamentarium of treatments, including medical therapy, pacemaker therapy, surgical therapy, and most recently catheter-based therapy. Careful advice, with emphasis on proven therapies and potential pitfalls, is crucial to facilitating the appropriate choices by patients. It is the purpose of this monograph to provide a rational approach to therapy, which must be individualized for each patient.

Atherosclerotic involvement of extracoronary arteries in patients undergoing myocardial revascularization can cause severe postoperative complications and increase postoperative mortality. When associated vascular lesions are detected preoperatively, appropriate operative approach, perfusion technique, and postoperative treatment can be planned and thus reduce the risk of perioperative stroke. In order to assess the incidence and the degree of associated vascular lesions, we performed routine preoperative echo-Doppler study of carotid vessels in all patients who were candidates for coronary artery bypass graft (CABG) between January and November 1998. Correlations between echo-Doppler findings, angiographic patterns of coronary lesions, and atherosclerotic risk factors were analyzed in all cases. Among 302 patients undergoing CABG, 186 (61.6%) had carotid disease, with a significant lesion in 31 (10.2%). Twenty-three patients (7.6%) had asymptomatic severe carotid disease. Whenever a significant carotid lesion was found, carotid endoarterectomy (CEA) was performed under local anaesthesia before CABG. A significant correlation between severity of coronary disease and incidence of severe carotid disease was found (p=0.02). Symptoms of carotid disease are not reliable as predictors of perioperative risk of stroke in patients undergoing CABG. In order to plan suitable operative approach and to prevent perioperative vascular complications, non-invasive carotid investigation should be routinely performed in such patients.