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Transesophageal echocardiography with the use of pediatric probes is nowadays commonly performed. However, in small children, insertion of a probe with a diameter of 7 mm may be traumatic or even impossible. We therefore tested a 17-element, 4 mm transverse plane probe in 136 pediatric patients, mainly in the operation room, catheterization laboratory, or the intensive care unit, and in three healthy adult volunteers. This probe was easy to insert, particularly during emergency situations, did not cause any complication in any patient, and provided satisfactory information despite the low number of elements. The use of a 4 mm transesophageal probe can improve the management of neonates with congenital heart disease in the operating room or the neonatal intensive care unit.

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Delay in development after open-heart surgery in infants has frequently been reported. Inadequate brain perfusion and oxygenation during deep hypothermic cardiopulmonary bypass (CPB) may play an important role. We investigated the effect of CPB on cerebral perfusion and oxygenation in 12 neonates and infants (age 0-11 months) undergoing open-heart surgery. Changes in cerebral blood volume (delta CBV; in ml/100 g brain tissue) and oxidation level of the intracerebral mitochondrial enzyme cytochrome aa3 (delta Cytaa3; in mumol/l) were measured with near infrared spectroscopy. Nasopharyngeal temperature (Tnas) for assessment of changes in brain temperature, and mean arterial blood pressure (MAP) were monitored continuously. CBV lowered during cooling and increased during rewarming. These changes were only related with changes in Tnas (p < 0.001; 0.07 ml.100 g-1/ degrees C). No relation was found with changes in MAP or pump flow rate of the heart-lung machine. During steady-state hypothermic CPB, changes in CBV were only related to changes in MAP (p < 0.001). The individual regression lines between delta CBV and MAP became steeper at lower absolute Tnas. Cytaa3 showed an increase shortly after the initiation of CPB in 9 patients, with a sustained decrease to baseline values in 8 patients towards the end of the CPB period. Two patients who had a circulatory arrest during CPB had a sharp decrease in delta cytaa3 after cessation of the heart-lung pump and showed no complete recovery of delta Cytaa3 to baseline at the end of the CPB period. We conclude that changes in CBV during CPB are related to changes in Tnas. During deep hypothermic steady-state CPB, changes in CBV and MAP were related to each other, suggesting lack of cerebral autoregulation. The large decrease in Cytaa3 in 2 patients with circulatory arrest suggests that this procedure compromises energy metabolism of the brain cell.

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From 1958 to 1992, 105 patients were operated for discrete (or membranous) subaortic stenosis (DSAS). Our surgical techniques changed during this period. Before 1980 DSAS was removed by a sharp excision leaving the part on the mitral valve untouched (n = 58). After 1980 blunt dissection was used to enucleate DSAS completely (n = 47). The operation for DSAS was combined with aortic valve replacement (AVR) in 7 instances. Follow-up with recent echo-Doppler studies was complete in 100 patients. Recurring or persisting DSAS led to reoperation in 17 patients. Sixteen of them had had sharp, incomplete resections. One patient from the group of complete blunt enucleations was reoperated on twice. The interval between the first operation and the first reoperation averaged 9.7 years (range: 1-33 years). Nine reoperated patients had AVR. The risk factors for AVR were older age at first operation or late reoperation. In our early experience five patients died after operation. Another three patients died following one or more reoperations. Blunt dissection never led to complete AV block. It follows the anatomical cleavage planes and always allowed for complete and safe removal of DSAS. Although the follow-up is shorter, blunt enucleation thus far has had a lower incidence of reoperation.

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OBJECTIVES: To elucidate the effect of cardiopulmonary bypass on cerebral perfusion and on the autoregulatory ability of the cerebral vascular bed of infants and young children. SETTING: Operating room. DESIGN: Prospective study. PATIENTS: Thirteen newborn infants and young children undergoing open-heart surgery. INTERVENTIONS: Cerebral blood flow velocity was monitored in the patients undergoing open-heart surgery from just before the induction of anesthesia until the discontinuation of anesthesia after completion of the surgery. MEASUREMENTS AND MAIN RESULTS: Cerebral blood flow velocity was assessed by semicontinuous measurement of temporal mean blood flow velocity in the middle cerebral artery using a range-gated, pulsed Doppler flowmeter with a transducer that was firmly attached to the left temporal region of the head. Mean arterial pressure (MAP) and nasopharyngeal temperature were continuously monitored. During hypothermic (18.4 degrees C to 31.9 degrees C) cardiopulmonary bypass, cerebral blood flow velocity decreased and showed a close relationship with nasopharyngeal temperature (p less than .0001). During steady-state cardiopulmonary bypass, cerebral blood flow velocity showed a correlation with MAP (p less than .01). The nasopharyngeal temperature influenced this relationship: at lower (absolute) nasopharyngeal temperatures, lack of cerebral autoregulation was more common. CONCLUSIONS: The finding suggests that cerebral blood flow decreases with decreasing nasopharyngeal temperature. During hypothermic cardiopulmonary bypass, cerebral autoregulation seems to be easily disturbed, especially at low nasopharyngeal temperatures.

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This report describes the experience of the Leiden University Hospital with the arterial switch operation for transposition of the great arteries, with and without ventricular septal defect, and for the Taussig-Bing-anomaly. The longest follow-up was 13 years and 9 months. Follow-up shows good results with almost all surviving patients in functional class I and with a sinus rhythm. Supravalvular pulmonary artery stenosis is noted in some of the patients but is almost always mild and does not show any tendency to progression. Insufficiency of the aortic valve is seen less frequently. Until now it has not caused great concern but, of course, follow-up is still limited.

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Between August 1985 and May 1990, 27 neonates and infants underwent combined correction of intracardiac and aortic arch anomalies through a median sternotomy. Coarctation (CoA) was combined with VSD (6), AVSD (2), Taussig-Bing (TB) heart (5), transposition of the great arteries (TGA) (1), TGA + VSD (2), congenitally corrected TGA + VSD (1) and VSD + myxoid stenotic outlet valves (1). Interrupted aortic arch (IAA) was combined with VSD (10) and TB heart (1). Two patients had IAA type B as well as CoA. Age at operation varied from 2 to 243 days with a mean age of 51 days. Twenty patients (70%) were younger than 30 days. One TGA + VSD and all TB hearts had maligned outlet septum and right ventricular outflow tract obstruction (RVOTO). Posterior outlet septum deviation and left ventricular outflow tract obstruction (LVOTO) occurred in 8 patients with malalignment VSD and IAA (7) or CoA (1). Aortic arch reconstruction was performed using extended end-to-end anastomoses. In 3 patients, arch hypoplasia necessitated patch implantation. VSDs were closed through the right atrium unless the anatomy dictated otherwise. One TB heart was reconstructed with a Kawashima procedure. All other TB hearts and all TGAs were corrected with arterial switch operation. Obstructing outlet septum was resected whenever necessary. Follow-up was complete and included echo-Doppler control. Eleven patients had postoperative heart catheterisation. Early mortality was 18.5% (5 patients). Persisting LVOTO or RVOTO was responsible. There was no late mortality. Five patients were reoperated upon: 3 for stenotic anastomoses and 2 for a subaortic membranous stenosis. Successful balloon dilatation of recoarctation was performed four times.(ABSTRACT TRUNCATED AT 250 WORDS)

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We studied the effect of vasodilation on regional myocardial blood flow and oxygen consumption of the left ventricular free wall by infusing 10 micrograms/kg/min sodium nitroprusside into 7-week-old conscious lambs with and without aortopulmonary left-to-right shunts. Resting myocardial oxygen consumption in the 13 shunt lambs was significantly higher than in the nine control lambs (989 +/- 104 [+/- SEM] vs. 432 +/- 41 mumol/min/100 g left ventricle). This was achieved by a significantly higher left ventricular myocardial blood flow (294 +/- 33 vs. 143 +/- 16 ml/min/100 g left ventricle) because the arteriovenous oxygen concentration difference across the left ventricular free wall was similar in shunt and control lambs. Infusion of nitroprusside did not significantly change myocardial oxygen consumption and regional myocardial blood flows at 10 and 50 minutes after the onset of the infusion. This occurred despite a substantial drop in aortic and left atrial pressures and stroke volume, which decreases wall stress as well as external work of the left ventricle. Heart rate, however, increased significantly. We postulate that, during infusion of nitroprusside, the potential decrease in myocardial oxygen consumption due to a decrease in wall stress and external work of the left ventricle is neutralized by the consequences of the increased heart rate. In view of this and because of its hemodynamic effects, we do not consider sodium nitroprusside useful in the treatment of circulatory congestion in patients with left-to-right shunts, normal arterial pressures, and normal systemic blood flows.

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We studied the effect on the circulation of reducing peripheral vascular resistance by infusing sodium nitroprusside into lambs of three different age groups (subgroup A, 11-26 days, subgroup B, 32-52 days, and subgroup C, 61-88 days of age) with and without an aortopulmonary left to right shunt. Infusion of 10 micrograms/kg/min nitroprusside over 2 h decreased aortic and left atrial pressures markedly and increased heart rate, whereas systemic, pulmonary, and left to right shunt blood flows hardly changed. Within 30 min after the onset of infusion, the hemodynamic variables stabilized. Aortic and left atrial pressures were still below control levels at that time. The different flows remained the same and heart rate, after an initial fall, increased again. The pattern of hemodynamic changes was not influenced by age or the presence of an aortopulmonary left to right shunt. Based on this study, we do not advocate sodium nitroprusside administration in case of a left to right shunt with normal arterial pressure and systemic blood flow.

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We studied the effect on the circulation of the catecholamines isoproterenol, dopamine, and dobutamine in chronically instrumented lambs with aortopulmonary left-to-right shunts (ages 11 to 87 days) and without shunts (ages 8 to 97 days). Infusion of 0.1 microgram/kg/min isoproterenol or 10 micrograms/kg/min dobutamine markedly increased heart rate and systemic and pulmonary blood flows, while stroke volume and the left-to-right shunt flow did not change. Since pulmonary blood flow increased and the left-to-right shunt flow did not change, the left-to-right shunt fraction decreased with the infusions of isoproterenol and dobutamine. The hemodynamic changes during the infusion of isoproterenol and dobutamine occurred immediately after the start of infusion and stabilized within a few minutes. The pattern of hemodynamic changes was not influenced by the presence of an aortopulmonary left-to-right shunt or by age. Infusion of 10 micrograms/kg/min dopamine caused only small hemodynamic changes. This study shows that heart rate and systemic blood flow in the lamb are closely related. Furthermore, it demonstrates that despite an increased systemic blood flow, left-to-right shunt flow does not change after infusion of isoproterenol and dobutamine. Any decision as to which positive inotropic agent might be preferred at an early age should await experimental work concerning the effect of these agents on the myocardial oxygen demand and on the distribution of the systemic blood flow.

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We measured myocardial blood flow (QLVFW) and O2 consumption of the left ventricular free wall (VO2, LVFW) in 13 chronically instrumented, 7-wk-old lambs with an aortopulmonary left-to-right shunt (S) and in 10 control lambs without a shunt (C). The measured VO2, LVFW was compared with the calculated values obtained by two predictive indexes, the rate-pressure product (RPP) and the pressure-work index (PWI). Measured VO2, LVFW in S lambs was significantly higher than in C lambs [983 +/- 104 (SE) vs. 475 +/- 57 mumol X min-1 X 100 g LV-1, P less than 0.001]. This was achieved by the significantly higher QLVFW (294 +/- 33 vs. 145 +/- 15 ml X min-1 X 100 g LV-1, P less than 0.002), since the arteriovenous O2 difference across the left ventricular free wall was similar in both groups of lambs. Total coronary blood flow per unit body mass in S lambs was higher than in C lambs (14.1 +/- 1.5 vs. 5.6 +/- 0.6 ml X min-1 X kg-1, P less than 0.001), not only because of the increased VO2, LVFW per unit muscle mass, but also because of the increased total heart weight (102.4 +/- 6.4 vs. 81.2 +/- 4.9 g, P less than 0.02). Correct estimation of VO2, LVFW by means of the RPP and the PWI was only possible in C lambs. In S lambs the estimated values were significantly lower than the measured ones.(ABSTRACT TRUNCATED AT 250 WORDS)

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Generalized edema resulting from severe protein-losing enteropathy occurred in three patients 12, 15, and 17 months after the Fontan operation. One patient originally had tricuspid atresia and the other two, univentricular heart disease. At operation a conduit had been inserted between the right atrium and pulmonary artery. Apart from the protein loss, the patients were in good health. The cardiac catheterization data obtained 0.8 to 2.4 years (median 1.3 years) after operation in the three patients with protein-losing enteropathy were compared with those of 18 patients in whom Fontan's operation had been performed because of tricuspid atresia (eight patients) or univentricular heart disease (10 patients). All had atriopulmonary connections. The mean right and left atrial pressures and systemic blood flows measured by dye dilution in the patients with and without protein-losing enteropathy did not differ. However, the patients with protein-losing enteropathy had a higher diastolic right atrial pressure. Since maximal antegrade flow in the superior vena cava after Fontan's operation occurs during atrial diastole, these observations suggest that an increase in diastolic right atrial pressure may result in protein-losing enteropathy because of impairment of blood flow and therefore congestion in the superior vena cava, subclavian vein, and thoracic duct.

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A retrospective study was done in 50 patients after Mustard's operation (group A) and in 204 patients after closure of a secundum atrial septal defect (group B) to analyze the postoperative dysrhythmias and to relate them to surgical factors. Forty-two percent of the patients in group A had dysrhythmias at the end of the follow-up, compared to 23% of group B patients. There was a high late mortality in group A (16%) significantly related to AF and AVJ. In group A a significant correlation was found between dysrhythmias and age at operation, use of cardioplegia, perfusion time, and the type of cannulation. In group B there was a significant relation between the location of the defect and the presence of abnormal pulmonary venous drainage. After ASD closure using hypothermia instead of cardiopulmonary bypass, the incidence of dysrhythmias was significant lower. Damage to the sinus node by cannulation and by suturing in the sinus node area is the main cause of the high incidence of dysrhythmias after atrial surgery. This high incidence should be a factor in the consideration of new types of operations.

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Up to December 1980 we performed 21 Fontan operations: 8 for tricuspid atresia and 13 for a functional monoventricle. Although palliative, the operation is currently a good method of treating tricuspid atresia. In our experience, the use of a sufficiently large atriopulmonary valved conduit assures a more satisfactory immediate postoperative hemodynamic result than the atriobulbar non-valved connection (RA-infund. tunnel). Good results can be obtained by a modified Fontan operation in patients with a monoventricle. However, with this malformation, very careful preoperative selection of patients is necessary with special regard to pulmonary vascular resistance. The connection between the right atrium and pulmonary artery was established by a valved conduit in 15 patients; no valve was incorporated in the other 6 patients. The largest prostheses gave the best immediate postoperative hemodynamic results. Two patients with monoventricle were successfully reoperated for persistent right-left shunt. The 13 patients so far followed up for at least a year show definite improvement as compared with their preoperative condition. Late complications from the valved prostheses have not been observed so far.

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