Results of Surgical Treatment of Congenital Heart Defects in Children with Down's Syndrome

We analyzed early and late results of surgical treatment of 100 consecutive children with Down's syndrome (DS) and congenital heart defect (CHD) who were operated on between 1990 and 1997. Fifty had common atrioventricular canal (CAVC), 24 ventricular septal defect, 8 the ostium primum atrial septal defect, 8 tetralogy of Fallot (TOF), 3 patent ductus arteriosus, 3 the ostium secundum atrial septal defect, and 4 CAVC coexisting with TOF. In 93 patients total correction was performed. The total death rate was 6%. Death in the CAVC group was 8%, but it decreased to 2.7% during the past 3 years. The children who were followed up (from 7 months to 6 years; mean, 39 months) are in NYHA class I or II. There were no reoperations. The postoperative course was complicated by pulmonary infections in 38% of patients, which converted to generalized infection in 10% and was the cause of death in 8% of patients. These results indicate that CHD in DS children can be repaired with a low death rate and low incidence of severe mitral atrioventricular valve regurgitation in the CAVC group. A high incidence of severe infections can influence the final results. Repair of CHD in infancy helps to eliminate problems connected with congestive heart failure and pulmonary hypertension.     

Pathologic Lung Function in Children and Adolescents with Congenital Heart Defects

Lung function tests (i.e., spirometry, flow volume, and body plethysmography) were performed in 213 patients (age 6–21 years, mean 11.3 years) with hemodynamically significant congenital heart defects: atrial septal defect, ventricular septal defect (VSD), tetralogy of Fallot, aortic stenosis and coarctation of the aorta. We measured lung vital capacity, total lung capacity (TLC), residual volume (RV), the percentage ratio of the latter two measurements (%RV/TLC), maximal expiratory flow rates at 25% and 50% of vital capacity, and specific airway conductance. Pulmonary restriction dominated in patients with tetralogy of Fallot; pulmonary hyperinflation was more frequent in patients with VSD and coarctation of the aorta; and obstruction of the airways was observed most frequently in patients with tetralogy of Fallot. In conclusion, we found a range of pathologic lung function parameters in patients with hemodynamically significant congenital heart defects.     

Respiratory Syncytial Virus in Patients with Congenital Heart Disease: A Contemporary Look at Epidemiology and Success of Preoperative Screening

Awareness of respiratory syncytial virus (RSV) as a serious pathogen in the child with congenital heart disease is increasing. We studied the impact of RSV lower respiratory tract disease on patients in a large academic pediatric cardiology practice. We found that RSV disease necessitating hospitalization occurs in congenital heart disease patients well into the second year of life. Although pulmonary hypertension remains a significant risk factor for morbidity in these patients, it does not appear to be as much of a factor as in the past. By implementing a nasopharyngeal RSV enzyme-linked immunoassay screening of young patients prior to cardiac surgery we found a reduction in community-acquired postoperative RSV disease. We postulate this will lead to a reduction in nosocomial disease in the postoperative care unit.     

Distribution of Symptomatic Congenital Heart Disease in Hong Kong

Racial group studies have identified differences in the occurrence of congenital heart disease (CHD) among ethnic populations. The aim of this study was to characterize the proportionate frequency and clinical profile of children with symptomatic cardiac abnormalities in Hong Kong. The hospital records of 666, mainly Southern Chinese children with symptomatic CHD, who were 4 years of age or younger and who were admitted to Grantham Hospital, Hong Kong, in 1994 and 1995 were analyzed retrospectively. Left-to-right shunting (45.0%) and pulmonary outflow obstruction (34.4%) were the most frequently diagnosed categories, followed by left ventricular outflow obstruction (8.3%), transposition of the great arteries (4.2%), conditions with intracardiac mixing (3.9%), and other cardiac lesions (4.2%). Compared with Western studies, pulmonary outflow obstruction (p < 0.0001), particularly tetralogy of Fallot and critical pulmonary stenosis, were more frequent in Chinese children. In contrast with previous reports, coarctation of the aorta (5%) does not seem to be uncommon in Chinese patients. Conversely, aortic stenosis and hypoplastic left ventricle may be rare in these children (1% vs 3% and 3–7%). Other cardiac lesions showed no consistent racial difference in the frequency of occurrence. Chinese patients with Down's syndrome had ventricular septal defect (38%) as the predominant lesion followed by atrioventricular septal defect (25%). Western studies usually report a reverse pattern for these two lesions. The mortality rate for the total cohort was 7.5%. However, of those with conditions with intracardiac mixing and left ventricular outflow tract obstruction many did not survive childhood (20% and 21%, respectively).     

Dynamic Three-Dimensional Echocardiographic Reconstruction of Congenital Cardiac Septation Defects

Dynamic three-dimensional echocardiographic reconstructions of 27 cardiac septation defects were performed in 19 sedated infants and children. Using a subxiphoid rotational scanning approach, complete visualization of the entire shape and breadth of the defect was attained in 11 of 16 ventricular septal defects and 9 of 11 atrial septal defects. This technique enabled the operator to cut slices from the three-dimensional block of echocardiographic data in order to present septation defects in a region- or lesion-oriented fashion. Poor baseline two-dimensional image quality and certain small septation defects that were readily obscured by nearby structures led to inadequate three-dimensional reconstructions. The application of dynamic three-dimensional echocardiography for assessment of cardiac septation defects uniquely provided (1) the ability to present en face views of atrial and ventricular septal defects; and (2) a means by which intracardiac anatomy can be displayed in a region- and lesion-oriented fashion for interventional and surgical planning purposes.     

Blood Flow Measurement by Magnetic Resonance Imaging in Congenital Heart Disease

Investigation of blood flow in the heart and vessels may provide insight into the function of the cardiovascular system and aid patient management decisions. Phase velocity cine magnetic resonance imaging (PVC MRI) is a powerful and accurate noninvasive technique to quantitate and analyze blood flow. This article describes the principles, performance, and potential limitations of PVC MRI measurements. Clinical applications of PVC MRI are then reviewed with an emphasis on the assessment of congenital heart disease.     

Radiofrequency Catheter Ablation of Tachycardia in Patients with Congenital Heart Disease

Patients with anomalies of the heart frequently suffer from arrhythmias that either are associated with a congenital heart defect or result from the course of the disease. For most of the bradyarrhythmias, appropriate timing of the initiation of treatment is more challenging than its eventual execution. In the case of tachycardias, technical aspects of treatment require more attention because the often imperative impact such tachycardias have on quality of life, morbidity, and mortality determine intervention timing. Increasingly, interventional electrophysiology is turned to as a potentially definitive and substrate-related treatment because of antiarrhythmic drug therapy's failure to prevent arrhythmia recurrences and the potential detrimental side effects from drug therapy seen in this particular patient population. Using the experience gained during the past 10 years in the treatment of patients with arrhythmias but without associated structural heart disease, several groups reported their results and difficulties with the application of such therapy to patients with congenital heart defects. In this report, we summarize our hospital's experience with transcatheter radiofrequency current application for treatment of various types of tachyarrhythmias in 139 children and adults with congenital heart defects, emphasizing the current limitations of such therapy and addressing the potential benefits expected from future technology. Patient ages ranged from 5 months to 76 years (mean 25.3 ± 17.7 years), including 56 children and adolescents less than 16 years of age. At least one attempt at surgical palliation or correction was made in 93 patients; the remaining 46 patients had no surgical intervention attempts. A total of 225 different tachycardias were found, 93 of which were based on a congenital arrhythmogenic substrate (e.g., an accessory pathway). Acquired substrates (e.g., scars or myocardial fibrosis) gave rise to the remaining 132 tachycardias. Radiofrequency current ablation (183 sessions) successfully treated 121 of 139 patients. Within a follow-up period of 21 months a recurrence of the intrinsically treated tachycardia was seen in 24 patients (10.7%); 13 of the 24 underwent a successful repeat session. There were no significant procedure-related complications. Young and adult patients with congenital heart disease can be safely and successfully treated for tachycardias with the use of radiofrequency current ablation. Because such treatment meets the specific needs of this patient group, early consideration for this therapy is recommended.     

Hemodynamic Abnormalities in Fetuses with Congenital Heart Disease

The purpose of this investigation was to assess left and right ventricular function, volume ejection fraction, combined stroke volume, and combined ventricular output in the human fetus with congenital heart disease compared to the normal healthy fetus. Seventy-two fetuses with a variety of in utero diagnosed congenital cardiac defects were compared with a control group of fetuses with structurally normal hearts matched for race, maternal age, and gestational age. We demonstrated significant hemodynamic changes in the fetus with congenital heart disease. There was a significant (p < 0.0001) decrease in the volume ejection fractions, biventricular stroke volume, and cardiac output in the congenital heart disease group compared to matched controls. Our findings suggest that hemodynamic abnormalities in the fetus with congenital heart disease are present before birth and we speculate that myocardial reserve may not be adequate to respond to hemodynamic stressors such as birth or heart surgery.     

Enteral Nutritional Support by Percutaneous Endoscopic Gastrostomy in Children with Congenital Heart Disease

One of the major problems of children with severe congenital heart disease (CHD) is their poor nutritional status. Among other consequences, it influences the surgical outcome. Retrospectively we present our experience with percutaneous endoscopic gastrostomy (PEG) in 15 children with CHD. This technique allows enteral nutritional support without the disadvantages related to long-term nasogastric tube feeding. Major complications were absent, and minor complications were rare both at PEG insertion, which was performed under deep sedation, and during feeding via PEG tube. In 4 of the 8 children who were followed for at least 6 months the age-matched body weight increased more than one standard deviation. In 2 other patients it increased more than 0.5 standard deviations. In 7 children the tube was removed after 2.5 to 42 months since enteral support was no longer necessary. Apart from initial reservations the parental acceptance of PEG was good. We conclude that the PEG is a safe and reliable technique to support enteral nutrition in children with severe CHD.     

Congenital Heart Disease Among 815,569 Children Born Between 1980 and 1990 and Their 15-Year Survival: A Prospective Bohemia Survival Study

The objective of this study was to ascertain the prevalence and survival rate of children born with a heart defect. A total of 816,569 children live-born between 1980 and 1990 in Bohemia (52,478 km², population 6.314 million, western Czech Republic) were followed up and those with suspected heart disease referred to a center. Echocardiography was done in all of them. All dead children were autopsied. Congenital heart disease was found in 5030 of 816,569 children (6.16 per 1000 live births). The most frequent conditions were ventricular septal defect (41.59%), atrial septal defect (8.67%), aortic (7.77%) and pulmonary (5.81%) stenoses, transposition of the great arteries (5.39%), coarctation of the aorta (5.29%) and persistent ductus arteriosus (5.07%). The first week was survived by 92.46%, the first month by 89.14%, 6 months by 82.42%, and the first year of life by 80.02%, and 77.11% (95% CI 75.91–78.31%) survived to age 15 years. The best prognosis was found in pulmonary stenosis (15-year survival 95.55%), atrial septal defect (92.04%), persistent ductus arteriosus (90.59%), ventricular septal defect (89.37%) and aortic stenosis (88.39%). The worst results were attained in hypoplastic left heart, truncus arteriosus and pulmonary atresia with intact ventricular septum. In conclusion, the prevalence of congenital heart disease was 6.16 per 1000 live births; 77.11% of patients survived to age 15 years.     

Congenital Subclavian Artery to Subclavian Vein Fistula Presenting with Congestive Heart Failure in an Infant

Contrary to acquired arteriovenous fistulas, the congenital malformations are very rare. Here we report a case of congenital arteriovenous fistula forming a communication between the right subclavian artery to subclavian vein. To our knowledge, there is no similar case in which an infant has been successfully operated on for cardiac failure.     

Pressure-Regulated Volume Control vs Volume Control Ventilation in Infants After Surgery for Congenital Heart Disease

The objective of this investigation was to compare how two modes of positive pressure ventilation affect cardiac output, airway pressures, oxygenation, and carbon dioxide removal in children with congenital heart disease in the immediate postoperative period. The investigation used a one group pretest–post-test study design and was performed in the pediatric cardiac intensive care unit in a university-affiliated children's hospital. Nine infants were enrolled immediately after repair of tetralogy of Fallot (2) or atrioventricular septal defects (7) with mean weight = 5.5 kg (4.2–7.3 kg). Children were admitted to the pediatric cardiothoracic intensive care unit after complete surgical repair of their cardiac defect and stabilized on a Siemen's Servo 300 ventilator in volume control mode (VCV1) (volume-targeted ventilation with a square flow wave pattern). Tidal volume was set at 15 cc/kg (total). Hemodynamic parameters, airway pressures and ventilator settings, and an arterial blood gas were measured. Patients were then changed to pressure-regulated volume control mode (PRVC) (volume-targeted ventilation with decelerating flow wave pattern) with the tidal volume set as before. Measurements were repeated after 30 minutes. Patients were then returned to volume control mode (VCV2) and final measurements made after 30 minutes. The measurements and results are as follows: After correction of congenital heart defects in infants, mechanical ventilation using a decelerating flow wave pattern resulted in a 19% decrease in peak inspiratory pressure without affecting hemodynamics, arterial oxygenation, or carbon dioxide removal.     

Plasma Nitric Oxide Products Correlate with Cardiac Index of Congenital Heart Disease

We wished to determine the relationship between circulating levels of nitric oxide (NO) and cardiac index (CI) in children with congenital heart diseases. We measured the plasma levels of nitrate/nitrite (NO _x ), the stable end products of NO production as well as tumor necrosis factor-α (TNF-α), atrial natriuretic peptide (ANP), and brain natriuretic peptide in relation to various parameters determined simultaneously. The plasma NO _x levels correlated negatively with CI (r=−0.541, p < 0.05). No correlation was observed between NO _x and cardiac output. TNF-α correlated with NO _x levels (r= 0.593, p < 0.005) but not with either CI or cardiac output. Plasma levels of ANP and TNF-α were higher in atrial septal defect than those in the control group (p < 0.001 and p < 0.05, respectively). Elevated plasma NO _x could explain the increased basal release of endothelial NO due to high pulmonary blood flow. Plasma NO _x correlate negatively with CI in young patients with left-to-right shunt congenital heart diseases.     

Inhalation of Low-Dose Nitric Oxide to Evaluate Pulmonary Vascular Reactivity in Children with Congenital Heart Disease

The objective of this study was to investigate the efficacy of low-dose nitric oxide (NO). The study used fifteen consecutive Japanese preoperative patients (7 males and 8 females) with congenital heart disease and pulmonary hyptertension (mean pulmonary arterial pressure >30 mmHg), 6 of these patients had Down's syndrome. Hemodynamic measurements were taken in room air, 100% oxygen, 5 and 40 parts per million NO (NO5 and NO40) by inhalation. The differences between two observations within the same group were determined by the two-tailed paired t-test. A pulmonary vascular resistance (R _p) regression curve was constructed by using linear regression analysis. The percentage change in pulmonary arterial pressure per systemic arterial pressure (P _p/P _s) with NO40 (P _p/P _s-40) exceeded that of P _p/P _s-5 (p < 0.0001). The percentage change for the R _p with NO40 (Rp-40) was larger than that for the R _p-5 (p= 0.0003). The percentage change of P _p/P _s-5 and that with oxygen were similar (p= 0.266). The relationship between R _p-5 and R _p-40 was linear. In conclusion, the effects of NO5 were equivalent to 100% oxygen but less than NO40. NO5 should initially be used to test pulmonary reactivity. If there is no response, patients should still be given NO40.     

Congenital Malformations of the Tricuspid Valve in Siblings

The occurrence of familial heart disease in association with tricuspid atresia is rare. The first reported instance of tricuspid atresia and Ebstein's anomaly in siblings is presented. The presence of these two distinct pathologic variants of tricuspid valve malformations in siblings suggests that these malformations result from a common abnormality occurring during the development of the inlet portion of the right ventricle.     

Technetium-99m Hexamethyl Propylenamine Oxime Lung Clearance in the Estimation of Pulmonary Hypertension in Congenital Heart Disease: A Preliminary Comparative Study with Cardiac Catheterization and Pathology

Thirty-six patients ranging in age from 7 months to 15 years and weighing from 5300 g to 49 kg (24 undergoing corrective surgery and 12 cases with reversed shunt and no operation) underwent technetium 99m hexamethyl propylenamine oxime (Tc-99m HMPAO) lung clearance study and the results were compared with catheterization and pathology. Patients were allocated into three groups with respect to pathological grading (Heath–Edwards' classification) and the results were correlated on the basis of pathology. In group I (grades I and II), Pearson correlation coefficient was 0.86 with pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), and Tc-99m HMPAO lung clearance (t _1/2). Pearson correlation coefficients were 0.863 and 0.88 in the second (grade III) and third group (with reversed shunt and no operation). There were statistically significant differences among the groups with respect to PAP, PVR, or t _1/2. The results of radionuclide study (t _1/2) were very well correlated within the groups with respect to hemodynamic parameters (PAP and PVR). Tc-99m HMPAO has potential as a highly sensitive indicator for detecting early and minimal microvascular lung injuries, and it may reflect accurate lung clearance and retention enabling an estimation of the state of pulmonary hypertension.     

Assessment of Cardiovascular Anatomy in Patients with Congenital Heart Disease by Magnetic Resonance Imaging

The following discussion addresses the assessment of cardiovascular anatomy in patients with congenital heart disease by magnetic resonance (MR). The focus of this review is on the techniques of performing the MR examination. In particular, individual pulse sequences are described and illustrated with their strengths and weaknesses. Imaging strategies using the described pulse sequences are proposed. The pulse sequences described are widely available on most MR scanners. Therefore, the proposed imaging strategies are clinically proven to be simple and effective ways to perform cardiac MR examination for the assessment of cardiovascular anatomy in patients with congenital heart disease. Functional imaging, such as flow analysis and ventricular function assessment, are discussed elsewhere in this issue.     

Centralization of Pediatric Heart Surgery in Sweden

In Sweden, which has a population of 8.9 million people, pediatric heart surgery was previously performed in four cities. After a long, difficult process, centralization of pediatric heart surgery to two centers was achieved in 1993. The overall 30-day mortality for open-heart surgery on infants and children of 9.5% before the centralization (1988–1991) was reduced to 1.9% in 1995–1997. A causal relationship between the mortality rates before and after the centralization is impossible to prove. Heart surgery was concentrated to the two centers with the lowest surgical mortality, and the reduction in surgical mortality was observed over a short period of time which makes it likely that the centralization of the surgical activity promoted the improved results. During the later time period the amount of more complex surgery was clearly increased compared to that performed previously.     

A Case with Weaver Syndrome Operated for Congenital Cardiac Defect

An 11-month-old Turkish female infant with Weaver syndrome together with atrial septal defect and patent ductus arteriosus which was operated successfully is reported. Weaver syndrome is a very rare disorder of unknown etiology characterized by accelerated growth of prenatal onset, advanced osseous maturation, special craniofacial features, umbilical hernia, and hoarse low-pitched cry. Congenital cardiac defect is not a usual finding. The presented case is the first reported child with Weaver syndrome in the literature operated for a congenital cardiac defect.     

The Use of High-Resolution Computed Tomography in the Evaluation of Pulmonary Hemodynamics in Patients with Congenital Heart Disease: In Pulmonary Vessels Larger Than 1 mm in Diameter

High-resolution computed tomography (HRCT) was carried out in 36 patients with congenital left-to-right shunt disease and 10 normal control subjects to assess the feasibility of CT in the evaluation of pulmonary hemodynamics. The patients had a left-to-right or a bidirectional shunt and the hemodynamic data obtained by cardiac catheterization in these patients were compared to the information obtained by CT imaging. The pulmonary/systemic blood flow (Q _p/Q _s) ratio and pulmonic/systemic resistance (R _p/R _s) ratio had a significant correlation with the pulmonary artery/bronchus (PA/Br) ratio (r= 0.54 and r=−0.37, respectively) and pulmonary vein/bronchus (PV/Br) ratio (r= 0.66 and r=−0.66, respectively), and the R _p/R _s and mean PA pressure also showed a significant correlation with the PA/PV ratio (r= 0.53 and r=−0.61, respectively) in the mid-lung field when accompanying bronchi were 4.0–5.9 mm in diameter. There was no correlation between the hemodynamic data and the size of the central and hilar PA or with the rate of PA tapering. With HRCT, it is possible to evaluate pulmonary hemodynamics in patients with congenital heart disease with a left-to-right or bidirectional shunt, particularly R _p/R _s and mean PA pressure, which have been very difficult to obtain noninvasively. The small-sized pulmonary vessel/Br ratio or the small-sized PA/PV ratio could offer very useful information, but the dimension of the central PA provided the least useful information.