A fenestration in the atrial septum may be temporarily beneficial in high–risk patients undergoing the modified Fontan operation. The venous system is decompressed into the left atrial cavities resulting in an improvement in the systemic output at the expense of a moderate arterial desaturation due to a right–to–left shunt. Two groups of patients undergoing the modified Fontan operation were compared. Those treated with the classic operation (non–fenestrated Fontan group, n=56) had lower prevalence of preoperative risk factors for the Fontan operation than those undergoing the Fontan operation with a fenestrated patch (n=91). Nevertheless, early results of mortality, repair take–down and morbidity (duration of pleuropericardial effusions) were comparable or better in the fenestrated Fontan group. By regression analysis the presence of a fenestrated patch was the major determinant in the reduction in the amount and duration of postoperative effusion. Of the early 73 survivors in the fenestrated Fontan group, fifty tolerated the closure of the fenestration, which occurred either spontaneously (five cases) or was achieved by a clamshell device during cardiac catheterization. Eleven patients failed the first attempt at fenestration closure, but this was successful at the second attempt a few months later. Coil embolization of arterial collaterals to the lung circulation and balloon dilatation of pulmonary artery stenoses were required in some cases. Other patients following the Fontan operation with a fenestrated patch showed an improvement of their ventricular function which was initially impaired. This favorable experience demonstrates the usefulness of the “fenestrated Fontan approach” in patients who are suboptimal candidates for the classic operation, provided that the preoperative risk factors are potentially reversible.

Thrombolysis was used in 13 procedures to treat eight patients with massive thrombosis of coronary aneurysms due to Kawasaki disease. The patients have now been followed for periods ranging from 2.5 years to 7.4 years subsequent to treatment. The procedures included intracoronary or intravenous infusion of urokinase and intravenous administration of tissue plasminogen activator. Thallium myocardial imaging, coronary arteriography and echocardiography were used for evaluation of the efficacy of the therapy and for follow-up studies. The latest time of treatment was 17 months after the onset of the disease. No new formation of massive thrombus was observed in any of the aneurysms. In five patients, eight of 13 procedures were judged to be successful. In the four patients with symptoms of myocardial ischemia, thrombolysis was undertaken immediately after the onset of symptoms. In the other patient, thrombolysis was attempted 36 days after the onset and produced remarkable improvement in the degree of ischemia. In the other four patients with no symptoms of ischemia, the therapy was undertaken when thrombus was detected in a coronary aneurysm. Aortocoronary bypass surgery was undertaken subsequent to the thrombolytic therapy in three patients, but proved satisfactory in only one patient. At follow-up, five patients have shown improvement in the degree of myocardial ischemia after treatment. Our results suggest that careful observation is needed to detect formations of thrombus in large coronary arteries for at least 1½ years after the onset of Kawasaki disease. Even if repeated thrombolytic therapy is required, it seems to be effective in checking the progression of ischemic heart disease.

Clinical and Doppler echocardiography were performed in 65 patients who had undergone ligation of the arterial duct between January 1978 and December 1991. Of the patients, 12 (18%) patients had residual patency as demonstrated by color Doppler, while three (4.6%) of these had continuous murmurs. There was no association between residual patency and the age at surgery, the weight at surgery or the follow-up interval.

A patient with the rare combination of an unusual form of pulmonary atresia with intact ventricular septum and a Marfan-like disease is presented. She was extremely cyanosed in childhood but improved after construction of a left peripheral shunt at the age of nine years. She deteriorated gradually after the onset of atrial fibrillation at the age of 33, the subsequent course being complicated by a stroke and, finally, by intractable heart failure and death at the age of 39.

A complex case of congenital heart disease is presented which features isomerism of the left atrial appendages combined with bronchoatrial discordance and an anteriorly placed non-interrupted inferior caval vein draining to the left-sided atrium. This combination of anomalies has, as far as we are aware, not been described before. It emphasizes the importance of direct confirmation of atrial arrangement by atrial angiography or transesophageal echocardiography.

Congenital heart disease occurs in roughly 0.7% of live-births. Approximately one-half of these defects are severe, requiring surgical correction or palliation. In a large percentage of such procedures in children, moderate or profound hypothermic cardiopulmonary bypass is employed. Because, nowadays, early correction of the defect rather than a palliative procedure is more frequently pursued, the surgeon, anesthesiologist, and perfusionist are called upon to manage younger and smaller children undergoing longer and more complex operations which necessitate longer times on bypass. Due to the particular underlying heart defect, the pathway of flow and viscosity of the blood are frequently different from those encountered in the adult with atherosclerotic coronary arterial or valvar heart disease. Thus, it is important for those caring for children undergoing cardiac surgery utilizing bypass to be well informed about its possible detrimental effects on the various organs. The purpose of this review will be to focus on the effects of bypass on flow to, and metabolism of, the organs and to highlight what is known with regard to these features in children rather than adults.

The activation of inflammatory systems as a consequence of cardiopulmonary bypass represents one possible means by which inj ury to tissues and associated dysfunction of organs may occur in the postoperative cardiac patient, both pediatric and adult. Kirklin and colleagues demonstrated in the early 1980's that complement activation occurs as a consequence of blood exposure to the extracorporeal circuit. Subsequent studies demonstrated this to be true in systems using both bubble and membrane oxygenators. The anaphylatoxin C5a and its metabolite C5a des arg are produced during activation of the complement cascade. They are potent stimulants which may induce activation of neutrophils. This activation may be manifested as changes in shape, decreased cellular deformability, and changes in adhesive and secretory function. Activation of neutrophils by these fragments of complement could contribute to neutrophilmediated damage to tissues by promoting retention of neutrophils in vascular beds and secretion of cytotoxic substances. Recent studies demonstrating the release of neutrophil granular enzymes into the plasma following cardiopulmonary bypass are evidence that activation of neutrophils is taking place in this setting.

Cardiopulmonary bypass makes a mess of homeostasis. Extracorporeal perfusion produces pulseless flow without physiologic controls, showers microemboli throughout the body, and brings blood diluted with additives to an enzymatic boil. Much of the morbidity associated with open heart surgery is due to contact of blood with the synthetic surfaces of the extracorporeal perfusion circuit. Bypass temporarily impairs function of every organ, alters concentrations of over 25 vasoactive substances within the plasma, and causes massive retention of fluid. In short, cardiopulmonary bypass makes patients sick.

Bleeding after cardiopulmonary bypass remains a significant problem for the cardiac surgeon. In addition to surgically-induced bleeding, the major cause of loss of blood is an acquired coagulopathy. Impaired function, produced either by the mechanical effect of cardiopulmonary bypass or by the influence of hemostatic activation of platelets during bypass, is the main cause of postoperative bleeding. The tendency towards bleeding in infants and neonates is additionally influenced by the type of operation, those with cyanotic heart disease demonstrating an increased tendency to bleeding. Most of the procedures are more complex than in adults, and many reoperations are necessary, particularly if primary correction is not possible. Furthermore, procedures for perfusion and cooling are mostly different from those used in adults. The operations are regularly performed using deep hypothermia or circulatory arrest, which may further impair the function of platelets. Yet the effect of low temperatures on hemostasis, with or without circulatory arrest, still remains unclear, since the immature system for coagulation in neonates may contribute to impaired hemostasis.

The current practice of cardiac surgery would be impossible without extracorporeal circulatory support. Although significant morbidity is still associated with these techniques of support, they are “tolerated” because the flexibility and practical advantages which they provide in clinical practice far outweigh the associated morbidity.

Cerebral hypothermia is the principal means of protecting the brain during cardiac surgery, permitting periods of reduced perfusion and/or circulatory arrest. For example, at 10–20°C, circulatory arrest for 45–75 minutes is tolerated in animals without subsequent behavioral or histopathologic evidence of neurologic injury. Nevertheless, clinically, die protective effect of hypothermia is far from complete. In children undergoing hypothermic circulatory arrest under equivalent conditions, coma, seizures, choreoathetosis, and developmental retardation are recognized as potential neurologic sequels, occurring widi a combined incidence of 10-30%. Neurologic complications (stroke, neuropsychologic change) also occur with distressing frequency in adults undergoing cardiac surgery, even in the absence of circulatory arrest. An improved understanding of the physiology of cerebral hypothermia during cardiopulmonary bypass and hypothermic arrest is needed to improve upon these results. This review will address current concepts and controversies regarding flow of blood to the brain and its metabolism during hypothermic cardiopulmonary bypass and their relationship to current techniques for cerebral protection.

Hypothermic circulatory arrest has been an important adjunct in pediatric cardiovascular surgery. Historically, use of hypothermia allowed the first intracardiac repair prior to the successful application of cardiopulmonary bypass and well before the advent of cardioplegic cardiac arrest. Today, the repair of many complex defectsis greatly facilitated by the use of hypothermic arrest. Despite the importance of the technique in the armamentarium of the congenital heart surgeon, the physiology of cerebral injury associated with hypothermic arrest has not been fully elucidated. To understand this physiology better, a number of investigators have focused on cerebral reperfusion after the event. In this review, we discuss findings from our own studies in the light of other available data on global and regional flow of blood to the brain following hypothermic arrest.

Over the past two decades, advances in equipment used for cardiopulmonary bypass and in operative techniques have resulted in a tremendous decrease in the mortality of patients undergoing surgical repair of congenital heart disease utilizing hypothermic circulatory arrest. Despite the widespread use of hypothermic arrest, opinion is not unanimous with regard to its safety. Previous studies which have examined neurological outcome following repair of congenital heart disease in infancy have generally agreed that when the period of arrest exceeds 60 minutes, there is increasing risk of cerebral injury.

Although the brain is the organ most sensitive to total bodily ischemia, and probably also most sensitive to the deleterious effects of cardiopulmonary bypass, it is also the most difficult organ in which to quantitate function accurately. Clinical studies allow sensitive neuropsychometric testing, as discussed elsewhere in this issue (see Wernovsky et al, p. 308). This is not possible in studies using animals. Even testing of gross neurological integrity in animals is complicated by the associated dysfunction of other organs which accompanies the insult of cardiopulmonary bypass with or without circulatory arrest on the whole body. For example, how should one evaluate an animal undergoing neurological testing which is unable to walk or eat, perhaps because of severe cardiorespiratory or gastrointestinal dysfunction following cardiopulmonary bypass and circulatory arrest. What is the contribution of neurological dysfunction to this state? Most importantly, how is the animal scored which does not survive, even though this may be a result of multiorgan dysfunction?

The dramatic reduction in surgical mortality associated with repair of congenital heart anomalies in recent decades has been accompanied by a growing recognition of adverse neurologic sequels in some of the survivors. Abnormalities of the central nervous system may be a function of coexisting cerebral abnormalities or acquired events unrelated to surgical management (such as paradoxical embolus, cerebral infection, or effects of chronic cyanosis), but insults to the central nervous system appear to occur most frequently during or immediately after surgery. In particular, techniques of support used during neonatal and infant cardiac surgery—cardiopulmonary bypass, profound hypothermia and circulatory arrest—have been implicated as important causes of cerebral injury. This paper will review the effects of bypass and deep hypothermic circulatory arrest on neurodevelopmental outcome.