Steven A. Webber

Influence of bidirectional superior cavopulmonary anastomosis on pulmonary arterial growth.

Right-sided BSCA provides for satisfactory pulmonary arterial growth in infants and children with complex congenital heart defects, and it could enhance the growth of a small right pulmonary artery. The growth of the left pulmonary artery, particularly in younger patients, needs close attention to confirm the safe role of BSCA in long-term palliation.

Double-blind placebo-controlled trial of corticosteroids in children with postpericardiotomy syndrome

SummaryThe objective of this study was to assess the efficacy of corticosteroids in hastening the recovery of children with postpericardiotomy syndrome, using a randomized double-blind placebo-controlled trial in a tertiary care referral center for pediatric cardiology and cardiac surgery. Twenty-one children, 6 months of age or older (mean age 3.9 years) with postpericardiotomy syndrome following open or closed heart surgery were administered either prednisone 2 mg/kg/day reducing to zero over 14 days (n=12) or placebo (n=9). Progress was monitored by daily clinical assessment and alternate day cross-sectional echocardiograms. The primary measures of efficacy were the number of patients in remission at 72 h and at 1 week. No difference in remission rates were found at 72 h, but at 1 week significantly more children treated with prednisone were in remission (placebo 3/9; prednisone 10/12,p=0.03). A trend to faster resolution of all symptoms and signs was seen in the prednisone-treated group but this was not associated with earlier hospital discharge. Enlargement of pericardial effusion was seen in two children treated with steroids. No complications of treatment were encountered. Prednisone hastens the recovery of children with postopericardiotomy syndrome. Pericardial effusions may increase in size despite the use of corticosteroids.

Myocardial Contractility in Premature Neonates With and Without Patent Ductus Arteriosus

Controversy exists as to whether a hemodynamically significant left-to-right shunt due to a patent ductus arteriosus (PDA) affects ventricular contractility. Load-dependent indices such as ejection fraction and shortening fraction have traditionally been used to assess contractility, but the relationship between the rate-corrected velocity of fiber shortening (MVCFc) and wall stress may be more suitable, as it is a preload-independent, afterload-adjusted method of assessing ventricular contractility. Age-related differences have been established for these variables in normal adults and children and it has been recommended for use in the premature neonate. The study was performed to assess left ventricular contractility in premature neonates with a significant left-to-right shunt due to a PDA. Using echocardiography, we measured the relationship of MVCFc to stress at peak systole (SPS) in two groups of premature infants. Group 1 consisted of 15 controls (680–1495 g, 25–32 weeks’ gestation), and Group 2 of 15 neonates with hemodynamically significant PDA (840–1635 g, 26–33 weeks’ gestation). In both groups, MVCFc was linearly and inversely related to SPS (p < 0.001). The regression equations were as follows: Group 1, MVCFc = −0.0153SPS + 1.70 (R2 = 0.68); and Group 2, MVCF = − 0.019SPS + 1.89 (R2 = 0.76). There was no significant difference in the relationship between the two groups, but their slopes were significantly steeper and had a higher Y-intercept than the relationship we previously reported for older children. This preliminary study establishes the normal MVCFc/SPS relationship in the premature neonate (25–33 weeks’ gestation) and suggests that premature infants function at a higher resting contractile state than older children. A hemodynamically significant PDA has no effect on contractility. These data will be useful in assessing left ventricular contractility in premature neonates with other types of ventricular loading and noncardiac stress.

Univentricular atrioventricular connection with subaortic stenosis: A staged surgical approach

A staged surgical approach was developed for the management of hearts with univentricular atrioventricular connection (double-inlet left ventricle or tricuspid atresia) and discordant ventriculoarterial connection with anatomical substrate for the development of subaortic stenosis. This consisted of initial palliation with pulmonary artery banding, followed by early elective relief of subaortic obstruction using a proximal pulmonary artery to ascending aorta anastomosis in infancy. Pulmonary blood flow was maintained at this time by creating a bidirectional superior cavopulmonary anastomosis. Over an 18-month period, 5 children, including 4 seen in the first week of life with aortic arch obstruction, were palliated with this approach. All patients survived operation and are asymptomatic with transcutaneous oxygen saturations of 80% to 85%. Completion of cavopulmonary repair is planned at 2 years of age. Although some authors have considered pulmonary artery banding contraindicated in these infants, the current staged approach offers an attractive alternative to the construction of a pulmonary artery to aorta anastomosis in the neonatal period.

Autoantibody production after cardiopulmonary bypass with special reference to postpericardiotomy syndrome

A prospective study of children undergoing open heart surgery with cardiopulmonary bypass showed that many of them produced autoantibodies. No association was found between these antibodies, including anticardiolipin antibodies, and the occurrence of postpericardiotomy syndrome.

Aortico-left ventricular tunnel associated with critical aortic stenosis in the newborn

SummaryAortico-left ventricular tunnel is a rare congenital malformation. A unique case of critical aortic stenosis in a neonate accompanying aortico-left ventricular tunnel is described. Successful surgical correction was performed without invasive studies following echocardiographic recognition of the defect.

Pulsed wave and color doppler findings in congenital pulmonary vein stenosis

SummaryA premature infant presented at 8 weeks of age with respiratory failure and pulmonary hypertension. Two-dimensional echocardiography was not diagnostic but color flow imaging and pulsed Doppler examination revealed turbulent and continuous pulmonary venous flow. Differing patterns of disturbed flow suggested varying severity of obstruction in individual pulmonary veins. The Doppler findings are compared to the angiographic and autopsy data.

Prognosis in asplenia syndrome—a population-based review

The prognosis for the fetus or neonate with asplenia syndrome is unknown as population-based data are unavailable. Factors influencing survival in this syndrome were, therefore, assessed for the province of British Columbia by retrospective review of all cases diagnosed between 1970 and 1990. Particular attention was paid to the prognostic influence of palliative surgery, sepsis, extracardiac malformations, gastrointestinal disease, arrhythmias and sudden death. We identified 43 cases of asplenia syndrome, of which 40 were live-born (incidence 1/22,000 live‐births). Only one spontaneous death was noted during fetal life amongst approximately 5,000 fetal autopsies. Five cases had been diagnosed by fetal echocardiography, two of these pregnancies being terminated. Of the live-born infants, 28 (70%) underwent active management of their cardiac anomalies and of these, 14 are alive. Since 1980, 26 systemic-to‐pulmonary shunts have been constructed in 17 children with two operative deaths. Three children have had successful Fontan or bidirectional Glenn procedures. Systemic sepsis occurred in three children with no deaths. Three neonates underwent surgery for obstruction of the upper gastrointestinal tract without complication. Late sudden death occurred in four children with systemic-to-pulmonary shunts, none of whom had documented arrhythmias. Major extracardiac malformations were present in nine cases (21%), these contributing to death in two. Overall survival for all live-born infants is 35%. Sepsis and palliative surgery are no longer the major causes of death in asplenia syndrome, the current challenges being prevention of sudden death and the complexity of surgical repair of the cardiac malformations.

Diagnosis and outcome of dilated cardiomyopathy in the fetus

To identify the echocardiographic features and natural history of dilated cardiomyopathy in fetal life, we reviewed records of all fetal echocardiograms over the 10 year period 1980–1989 to identify cases of dilated cardiomyopathy without left ventricular outflow obstruction and conducted a retrospective review of the fetal echocardiograms and clinical course of those fetuses with dilated cardiomyopathy. In addition, all fetal losses, perinatal deaths and live-born infants presenting with dilated cardiomyopathy in the first seven days of life were identified from the British Columbia Pediatric Cardiovascular Pathology Registry and from inpatient records. The pathological findings and outcome for this group were also reviewed. Marked left ventricular dilatation and dysfunction without left ventricular outflow obstruction was diagnosed in five of 1,158 fetuses undergoing feta lechocardiography. These five fetuses were correctly distinguished from two others with critical aortic stenosis and severe left ventricular dysfunction. Two of the five fetuses had additional right ventricular dysfunction and dilatation and developed hydrops, while the remaining three with isolated severe left ventricular dysfunction did not and showed normal somatic growth. All fetuses were live-born with spontaneous labour occurring in four of five cases at a mean gestational age of 36.5 weeks. Four of the five infants died, with three deaths occurring in the first week of life. During the same 10 year period, two of 2450 autopsied stillbirths (both hydropic) were diagnosed with dilated cardiomyopathy. An additional 15 neonates (including the five identified by fetal echocardiography) were diagnosed in the first week of life with dilated cardiomyopathy, congenital myocarditis or endocardial fibroelastosis. Four were hydropic (all with associated right ventricular dysfunction). Only three of the 15 survive. Fetal echocardiography can accurately distinguish dilated cardiomyopathy from left ventricular outflow obstruction. In the absence of right-sided disease or premature closure of the oval fossa, severe left ventricular dysfunction is well tolerated in utero. The prognosis for fetal dilated cardiomyopathy is very poor.

Short- and long-term variability of echocardiographic stress-velocity indexes of cardiac function in a pediatric population

This study determined the short- and long-term variability of stress-velocity relationships at end systole and peak systole. A prospective study during the short term (0 to 15 and 0 to 30 minutes) and long term (0 to 1 and 0 to 12 months) was performed calculating variability by the limits of agreement method. The study was performed in a tertiary-care pediatric echocardiographic laboratory. Twenty-five normal children underwent repeat testing as described. Standard blood pressure, carotid pulse tracing, and M-echocardiography of the left ventricle was performed at the intervals described. The rate-corrected mean velocity of fiber shortening (MVCFC), echocardiographic stress at end systole (SES), and echocardiographic stress at peak systole (SPS) were calculated for all recordings. The slopes of MVCFC-SES and MVCFC-SPS were determined by regression and plotted. With these slopes, the second and third stress values were normalized to the first stress value for the short and long term. The differences in normalized MVCFC and MVCFC (delta MVCFC) for 15 to 0 minutes, 30 to 0 months, 1 to 0 month, and 12 to 1 month were obtained for both SES and SPS, and 95% limits of agreement were estimated. The mean delta MVCFC for SES and SPS for the short and long term were not different from 0 or each other, indicating no bias. The 95% limits of agreement of delta MVCFCs (i.e., variability for SES at 15 to 0 minutes, 30 to 0 minutes, 1 to 0 month, and 12 to 0 month) were +/- 0.18, +/- 0.24, +/- 0.34, and +/- 0.27, respectively, and for SPS +/- 0.18, +/- 0.24, +/- 0.33, and +/- 0.28. Variability showed an increasing trend with time but was significant only from 15 to 0 minutes and 1 to 0 month (p = 0.006). This study has established short- and long-term variability in the stress-velocity relationship that is essential for monitoring acute and chronic changes in ventricular contractility in an individual patient.