An Observational Study of Dialogue about Uncertainty in Clinician-Family Counseling Conversations Following Prenatal Diagnosis of Complex Congenital Heart Disease

Objective

Families who receive a prenatal diagnosis of complex congenital heart disease (cCHD) often experience severe psychological distress and identify uncertainty as a key source of that distress. This study examined clinician-family conversations during initial fetal cardiology consultations to identify the topics of uncertainty discussed.

Methods

In this observational, qualitative study, initial fetal cardiology consultations were audio-recorded, transcribed verbatim, and coded by two independent coders. A codebook was inductively and deductively developed and applied. This content analysis focused on uncertainty-related codes and associated themes.

Results

During 19 consultations including five clinicians, 13 different cardiac diagnoses were discussed (seven with high mortality risk). Median consultation length was 37 min (IQR: 26-51), with only 11% of words spoken by families. On average, 51% of total words spoken focused on uncertainty in relation to cardiac diagnosis, etiology, comorbidities, prognosis, childbirth, therapeutics, and logistics. Family-initiated discussion on uncertainty largely focused on childbirth and pregnancy and postpartum logistics.

Conclusions

Half of dialogue within initial fetal cardiology encounters discussed uncertainty surrounding prenatally diagnosed cCHD. Parent and clinician perspectives should be gathered on the essential content and optimal delivery of uncertainty-related topics.

Innovation

This study is conceptually and methodologically innovative as one of the first to examine audio-recorded dialogue between fetal cardiology clinicians and families.

Postoperative Morbidity and Interstage Hemodynamics Following Stage I Palliation in Patients with Turner Syndrome and Hypoplastic Left Heart Syndrome

BACKGROUND

Turner syndrome (TS) is associated with left-sided cardiac lesions, including hypoplastic left heart syndrome (HLHS). Mortality as high as 80-90% has been reported following stage I single-ventricle palliation (S1P) in patients with TS and HLHS (TS + HLHS). The specific factors that relate to poor outcomes are not well understood.

METHODS

This is a single-center, retrospective cohort study that includes 197 patients with HLHS who underwent S1P between 2008 and 2022. The clinical outcomes and interstage hemodynamics of TS + HLHS patients (N = 11) were compared with HLHS without TS (TS-HLHS), (N = 186).

RESULTS

Of the 11 TS + HLHS patients, 10 underwent S1P; 4 underwent Glenn and 1 had hemodynamics considered prohibitive for Glenn; only 1 survived to Fontan palliation. Post-S1P mortality was higher in TS + HLHS (60 v 25%, p = 0.017). Following S1P, TS + HLHS had higher rates of postoperative ECMO (70 v 28%, p = 0.006), surgical necrotizing enterocolitis (20 v 3%, p = 0.007), peritoneal drain placement (70 v 31%, p = 0.012), urinary tract infection (30 v 9%, p = 0.035), and ICU readmissions (median 5 v 1, p = 0.035). Interstage hemodynamics demonstrated higher right ventricular end diastolic, (11 v 8mmHg, p = 0.033), mean pulmonary artery (20 v 13mmHg) (p = 0.002), and left atrial pressures (9 v 6mmHg, p = 0.047) in TS + HLHS.

CONCLUSION

High mortality rates are described in TS + HLHS patients following S1P. In our cohort, despite most surviving more than 30 days post-S1P, long-term survival remained poor. Interstage catheterization data suggest poor physiologic candidacy for subsequent stages of single-ventricle palliation. Understanding the clinical and hemodynamic factors related to poor outcomes in TS + HLHS will help inform management for this population.

Pseudoaneurysm of Mitral-Aortic Intervalvular Fibrosa Imitating a Rhabdomyoma in a Fetus

•P-MAIVF may present prenatally. •Location of and color flow into an atrial mass raises suspicion for P-MAIVF. •The natural history of this presentation is still uncertain.

"I Just Want You to Hear That Term": Characterizing Language Used in Fetal Cardiology Consultations

The way clinicians communicate with parents during pregnancy about congenital heart disease (CHD) can significantly influence parental understanding of and psychological response to the diagnosis. A necessary first step to improving communication used in fetal cardiology consultations is to understand and describe the language currently used, which this paper aims to do. Nineteen initial fetal cardiology consultations with parents were audio-recorded, transcribed verbatim, and coded by two independent coders. A codebook was inductively developed and applied to all transcripts. The finalized coding was used to characterize fetal cardiologists' language. We identified four discourse styles employed in fetal cardiology consultations: small talk, medical, plain, and person-centered. Plain language was used to define and emphasize the meaning of medical language. Person-centered language was used to emphasize the baby as a whole person. Each consultation included all four discourse styles, with plain and medical used most frequently. Person-centered was used less frequently and mostly occurred near the end of the encounters; whether this is the ideal balance of discourse styles is unknown. Clinicians also used person-centered language (as opposed to disease-centered language), which is recommended by medical societies. Future studies should investigate the ideal balance of discourse styles and the effects of clinician discourse styles on family outcomes, including parents' decision-making, psychological adjustment, and quality of life.

Mapping parents' journey following prenatal diagnosis of CHD: a qualitative study

OBJECTIVE

To better understand parents' accounts of their prenatal and postnatal experience after prenatal diagnosis of CHD - particularly emotional processing and coping mechanisms - to identify strategies to improve support.

METHODS

This single-centre, longitudinal qualitative study included pregnant mothers and their support persons seen in Fetal Cardiology Clinic at Vanderbilt Children's Hospital from May through August 2019 for probable complex CHD. Twenty-seven individuals from 17 families participated in 62 phone interviews during pregnancy and postpartum: 27 conducted after the initial prenatal cardiology consultation, 15 after a follow-up prenatal visit, and 20 after birth. Applied thematic analysis approach was used to code and analyse transcribed interviews. Coding and codebook revisions occurred iteratively; intercoder reliability was >80%.

RESULTS

Patients included mothers (16 [59%]), fathers (8 [30%]), and other support persons (3 [11%]). Initial fetal diagnoses included a range of moderate to severe CHD. Prenatally, parents sought to maintain hope while understanding the diagnosis; planning for the future rather than focusing on day-to-day was more common if prognoses were better. Postnatally, with confirmation of prenatal diagnoses, parents' sense of control expanded, and they desired more active engagement in clinical decision making.

CONCLUSIONS

To enhance effective communication and support, understanding how parents conceptualise hope in relation to diagnosis and how that may evolve over time is critical. Expectant parents whose child has a significant risk of mortality may demonstrate hope by focusing on positivity. As prognostic uncertainty diminishes postpartum, the parental role on the team may shift, requiring clinicians to provide different support.

A rare case of isolated right atrial enlargement and TBX5 mutation associated with Holt-Oram syndrome

Holt-Oram syndrome or atriodigital dysplasia is commonly associated with cardiac malformations, most often with defects of the muscular septum. We describe the case of a fetus referred for fetal cardiology evaluation in the setting of right atrial enlargement without tricuspid valve abnormalities with small muscular VSDs, and without other significant cardiac lesions. On serial fetal echocardiograms, isolated right atrial enlargement was persistent as was relative fetal bradycardia without apparent AV block or other signs of abnormal conduction. Limb or other anatomic abnormalities were also not visualized on prenatal scans. A postnatal diagnosis of Holt-Oram Syndrome was made. In the setting of isolated right atrial enlargement, we suggest a comprehensive sonographic search for upper limb abnormalities as well as genetic evaluation.

Prenatally diagnosed coronary artery abnormalities in hypoplastic left heart syndrome are associated with a higher probability of heart transplantation

OBJECTIVE

Coronary artery abnormalities (CA) occur in patients with hypoplastic left heart syndrome (HLHS) and may be associated with higher mortality and heart transplantation (HT). We aimed to determine whether fetuses with HLHS and prenatal CA have a higher risk of death or HT.

METHODS

We performed a retrospective review of fetal echocardiograms with HLHS from 2011 to 2018. We excluded fetuses with ventricular septal defects, elective termination, death in utero, planned postnatal non-intervention, or absent follow-up data. Presence or absence of CA was determined by review of serial fetal echocardiograms. Survival analysis was used to evaluate the relationship between prenatal CA and death or HT.

RESULTS

Of 86 patients with fetal HLHS, 11 had prenatal diagnosis of CA. Of these, six required HT and five died (one after undergoing HT); only one remains alive without HT. Of those without prenatal CA (n=75), 25 died and 7 underwent HT. Patients with prenatal diagnosis of HLHS and CA had a significantly increased likelihood of death or HT (p-value <0.05).

CONCLUSION

nPrenatal diagnosis of CA in our cohort of patients with HLHS was associated with increased risk of death or HT. These data have significance for prenatal counseling and postnatal management. This article is protected by copyright. All rights reserved.

Contemporary Outcomes in Tetralogy of Fallot With Absent Pulmonary Valve After Fetal Diagnosis

Background

Tetralogy of Fallot with absent pulmonary valve is associated with high mortality, but it remains difficult to predict outcomes prenatally. We aimed to identify risk factors for mortality in a large multicenter cohort.

Methods and Results

Fetal echocardiograms and clinical data from 19 centers over a 10‐year period were collected. Primary outcome measures included fetal demise and overall mortality. Of 100 fetuses, pregnancy termination/postnatal nonintervention was elected in 22. Of 78 with intention to treat, 7 (9%) died in utero and 21 (27%) died postnatally. With median follow‐up of 32.9 months, no deaths occurred after 13 months. Of 80 fetuses with genetic testing, 46% had chromosomal abnormalities, with 22q11.2 deletion in 35%. On last fetal echocardiogram, at a median of 34.6 weeks, left ventricular dysfunction independently predicted fetal demise (odds ratio [OR], 7.4; 95% CI 1.3, 43.0; P=0.026). Right ventricular dysfunction independently predicted overall mortality in multivariate analysis (OR, 7.9; 95% CI 2.1–30.0; P=0.002). Earlier gestational age at delivery, mediastinal shift, left ventricular/right ventricular dilation, left ventricular dysfunction, tricuspid regurgitation, and Doppler abnormalities were associated with fetal and postnatal mortality, although few tended to progress throughout gestation on serial evaluation. Pulmonary artery diameters did not correlate with outcomes.

Conclusions

Perinatal mortality in tetralogy of Fallot with absent pulmonary valve remains high, with overall survival of 64% in fetuses with intention to treat. Right ventricular dysfunction independently predicts overall mortality. Left ventricular dysfunction predicts fetal mortality and may influence prenatal management and delivery planning. Mediastinal shift may reflect secondary effects of airway obstruction and abnormal lung development and is associated with increased mortality.

Impact of Socioeconomic Status, Race and Ethnicity, and Geography on Prenatal Detection of Hypoplastic Left Heart Syndrome and Transposition of the Great Arteries

BACKGROUND

Prenatal detection (PND) has benefits for infants with hypoplastic left heart syndrome (HLHS) and transposition of the great arteries (TGA), but associations between sociodemographic and geographic factors with PND have not been sufficiently explored. This study evaluated whether socioeconomic quartile (SEQ), public insurance, race and ethnicity, rural residence, and distance of residence (distance and driving time from a cardiac surgical center) are associated with the PND or timing of PND, with a secondary aim to analyze differences between the United States and Canada.

METHODS

In this retrospective cohort study, fetuses and infants <2 months of age with HLHS or TGA admitted between 2012 and 2016 to participating Fetal Heart Society Research Collaborative institutions in the United States and Canada were included. SEQ, rural residence, and distance of residence were derived using maternal census tract from the maternal address at first visit. Subjects were assigned a SEQ z score using the neighborhood summary score or Canadian Chan index and separated into quartiles. Insurance type and self-reported race and ethnicity were obtained from medical charts. We evaluated associations among SEQ, insurance type, race and ethnicity, rural residence, and distance of residence with PND of HLHS and TGA (aggregate and individually) using bivariate analysis with adjusted associations for confounding variables and cluster analysis for centers.

RESULTS

Data on 1862 subjects (HLHS: n=1171, 92% PND; TGA: n=691, 58% PND) were submitted by 21 centers (19 in the United States). In the United States, lower SEQ was associated with lower PND in HLHS and TGA, with the strongest association in the lower SEQ of pregnancies with fetal TGA (quartile 1, 0.78 [95% CI, 0.64-0.85], quartile 2, 0.77 [95% CI, 0.64-0.93], quartile 3, 0.83 [95% CI, 0.69-1.00], quartile 4, reference). Hispanic ethnicity (relative risk, 0.85 [95% CI, 0.72-0.99]) and rural residence (relative risk, 0.78 [95% CI, 0.64-0.95]) were also associated with lower PND in TGA. Lower SEQ was associated with later PND overall; in the United States, rural residence and public insurance were also associated with later PND.

CONCLUSIONS

We demonstrate that lower SEQ, Hispanic ethnicity, and rural residence are associated with decreased PND for TGA, with lower SEQ also being associated with decreased PND for HLHS. Future work to increase PND should be considered in these specific populations.

Risk Factors for Mortality and Circulatory Outcome Among Neonates Prenatally Diagnosed With Ebstein Anomaly or Tricuspid Valve Dysplasia: A Multicenter Study

Background

In a recent multicenter study of perinatal outcome in fetuses with Ebstein anomaly or tricuspid valve dysplasia, we found that one third of live‐born patients died before hospital discharge. We sought to further describe postnatal management strategies and to define risk factors for neonatal mortality and circulatory outcome at discharge.

Methods and Results

This 23‐center, retrospective study from 2005 to 2011 included 243 fetuses with Ebstein anomaly or tricuspid valve dysplasia. Among live‐born patients, clinical and echocardiographic factors were evaluated for association with neonatal mortality and palliated versus biventricular circulation at discharge. Of 176 live‐born patients, 7 received comfort care, 11 died <24 hours after birth, and 4 had insufficient data. Among 154 remaining patients, 38 (25%) did not survive to discharge. Nearly half (46%) underwent intervention. Mortality differed by procedure; no deaths occurred in patients who underwent right ventricular exclusion. At discharge, 56% of the cohort had a biventricular circulation (13% following intervention) and 19% were palliated. Lower tricuspid regurgitation jet velocity (odds ratio [OR], 2.3 [1.1–5.0], 95% CI, per m/s; P=0.025) and lack of antegrade flow across the pulmonary valve (OR, 4.5 [1.3–14.2]; P=0.015) were associated with neonatal mortality by multivariable logistic regression. These variables, along with smaller pulmonary valve dimension, were also associated with a palliated outcome.

Conclusions

Among neonates with Ebstein anomaly or tricuspid valve dysplasia diagnosed in utero, a variety of management strategies were used across centers, with poor outcomes overall. High‐risk patients with low tricuspid regurgitation jet velocity and no antegrade pulmonary blood flow should be considered for right ventricular exclusion to optimize their chance of survival.

Uncertainty of Prenatally Diagnosed Congenital Heart Disease: A Qualitative Study

IMPORTANCE

Parents who receive a prenatal diagnosis of congenital heart disease may experience more short- and long-term stress than those who receive a postnatal diagnosis. To identify potential interventions to ameliorate that stress, the longitudinal emotional experience of parents must first be understood.

OBJECTIVE

To better understand parents' accounts of their own prenatal experience, particularly aspects they found to be stressful or challenging, and to identify strategies to improve support.

DESIGN, SETTING, AND PARTICIPANTS

This qualitative study included analysis of transcripts of audio recorded telephone interviews with pregnant mothers and their support persons, as applicable, who were referred to and seen at the Fetal Cardiology Clinic at Vanderbilt Children's Hospital from May 2019 to August 2019 with an initial likely diagnosis of complex congenital heart disease at any gestational age. Data analysis was conducted from August 2019 to November 2019.

MAIN OUTCOMES AND MEASURES

An applied thematic analysis approach was used to code and analyze professionally transcribed interviews. Coding and codebook revisions occurred iteratively; intercoder reliability was assessed and confirmed routinely. One author coded all transcripts; a second author independently reviewed one-fifth of the transcripts at fixed intervals to ensure that interrater reliability remained greater than 80%.

RESULTS

Twenty-seven individuals from 17 families participated in 42 phone interviews during pregnancy, 27 conducted at the first time point after the initial prenatal cardiology consultation and 15 at the second time point after a follow-up prenatal cardiology visit. Most interviewees were mothers (16 interviewees [59%]; median [interquartile range] age, 30.0 [27.3-34.8] years) or fathers (8 interviewees [30%)], with a few support individuals (3 interviewees [11%]) (median [interquartile range] age of family member or support individual, 30.0 [26.0-42.0] years). Initial fetal diagnoses included a range of severe congenital heart disease. Uncertainty was identified as a pervasive central theme and was related both to concrete questions on scheduling, logistics, or next steps, and long-term unknown variables concerning the definitiveness of the diagnosis or overall prognosis. Practitioners helped families through their framing of uncertainty at various time points including before, during, and after the clinic visit.

CONCLUSIONS AND RELEVANCE

Families walk an uncertain path following a fetal diagnosis of severe congenital heart disease. The challenges faced by the cardiologists caring for them overlap in many ways with those experienced by pediatric palliative care practitioners. Potential future interventions to improve parental support were identified in the areas of expectation setting before the referral visit, communication in clinic, and identity formation after the new diagnosis.

Prenatally Diagnosed Congenital Ventricular Outpouchings: An Institutional Experience and Review of the Literature

Congenital ventricular outpouchings (CVOs) are rare congenital heart defects with limited data regarding prognosis and outcomes. We aimed to describe the characteristics, outcomes and factors associated with morbidity and mortality of prenatally diagnosed CVOs using our institutional experience and a review of published cases. A total of 86 cases of prenatally diagnosed CVOs were identified, including 3 from our institution and 83 cases identified from a review of the literature. Fetal and postnatal outcomes were analyzed for each case. Pericardial effusions (44%) and ventricular dysfunction (17%) were the most common associated findings. Excluding cases that resulted in pregnancy termination, mortality was 17%, with the majority (11/13) occurring in the prenatal period. Factors associated with mortality included an outpouching located on the left ventricle, a diagnosis of hydrops fetalis, the presence of a pericardial effusion, and an earlier gestational age at diagnosis. Of those that survived to delivery, 57% remained asymptomatic without the need for intervention, and the outpouching regressed or resolved in an additional 15%. Prenatally diagnosed congenital ventricular outpouchings are a dynamic form of congenital heart disease with a high fetal mortality rate. The outcomes associated with the outpouchings appear to be the most variable in the prenatal period and the first year after birth. Serial prenatal and postnatal evaluations should be performed to evaluate for a change in the characteristics of the outpouching.

Fetuses of Mothers with Thyroid Disease May Be at Higher Risk of Developing Supraventricular Tachycardia

OBJECTIVE

Fetal tachyarrhythmias complicate 0.5% of pregnancies, with high morbidity and mortality. We hypothesized that maternal factors may predispose to fetal supraventricular tachycardia (SVT).

STUDY DESIGN

We reviewed medical records of all 124 mothers who presented to the Vanderbilt Fetal Cardiology Clinic from 2004 to 2010 for fetal arrhythmias, excluding heart block. Maternal factors were compared between 28 fetuses with SVT and a control group of 112 fetuses screened for noncardiac conditions. The proportions were analyzed using chi-square or Fisher exact test for categorical variables and Wilcoxon rank sum test for continuous variables.

RESULTS

Of maternal factors, thyroid disease was statistically significant compared with controls. Among mothers whose fetuses had SVT, 21% had thyroid disease (83% hypothyroidism) compared with 3% of controls (p < 0.001).

CONCLUSION

In this cohort, the maternal thyroid disease was more common in fetuses with SVT compared with controls (odds ratio = 9.8, 95% confidence interval 2.3-42.3), suggesting closer screening for fetal arrhythmias and SVT in mothers with thyroid disease. Also, routine screening of thyroid functions and thyroid autoantibodies may be warranted in mothers of fetuses with SVT.

Outcomes and Predictors of Perinatal Mortality in Fetuses With Ebstein Anomaly or Tricuspid Valve Dysplasia in the Current Era: A Multicenter Study

BACKGROUND

Ebstein anomaly and tricuspid valve dysplasia are rare congenital tricuspid valve malformations associated with high perinatal mortality. The literature consists of small, single-center case series spanning several decades. We performed a multicenter study to assess the outcomes and factors associated with mortality after fetal diagnosis in the current era.

METHODS AND RESULTS

Fetuses diagnosed with Ebstein anomaly and tricuspid valve dysplasia from 2005 to 2011 were included from 23 centers. The primary outcome was perinatal mortality, defined as fetal demise or death before neonatal discharge. Of 243 fetuses diagnosed at a mean gestational age of 27±6 weeks, there were 11 lost to follow-up (5%), 15 terminations (6%), and 41 demises (17%). In the live-born cohort of 176 live-born patients, 56 (32%) died before discharge, yielding an overall perinatal mortality of 45%. Independent predictors of mortality at the time of diagnosis were gestational age <32 weeks (odds ratio, 8.6; 95% confidence interval, 3.5-21.0; P<0.001), tricuspid valve annulus diameter z-score (odds ratio, 1.3; 95% confidence interval, 1.1-1.5; P<0.001), pulmonary regurgitation (odds ratio, 2.9; 95% confidence interval, 1.4-6.2; P<0.001), and a pericardial effusion (odds ratio, 2.5; 95% confidence interval, 1.1-6.0; P=0.04). Nonsurvivors were more likely to have pulmonary regurgitation at any gestational age (61% versus 34%; P<0.001), and lower gestational age and weight at birth (35 versus 37 weeks; 2.5 versus 3.0 kg; both P<0.001).

CONCLUSION

In this large, contemporary series of fetuses with Ebstein anomaly and tricuspid valve dysplasia, perinatal mortality remained high. Fetuses with pulmonary regurgitation, indicating circular shunt physiology, are a high-risk cohort and may benefit from more innovative therapeutic approaches to improve survival.

Occlusion of the left main coronary artery os by a tethered aortic valve cusp

We report a 4-month-old girl who presented with poor ventricular function and was found to have occlusion of the left main coronary artery os by a tethered aortic cusp. The patient underwent surgical delamination of the aortic valve leaflet, revealing a normal left coronary os. After operative repair, her left ventricular function improved significantly. This diagnosis should be included in the differential in all children presenting with cardiac dysfunction.

A clinical prediction model to estimate the risk for coarctation of the aorta in the presence of a patent ductus arteriosus

BACKGROUND

Diagnosing coarctation of the aorta (CoA) in the presence of a patent ductus arteriosus (PDA) may require observation until PDA closure. The aim of this study was to create a model incorporating previously published indices to estimate the probability of neonatal CoA in the presence of a PDA.

METHODS

A retrospective "investigation" cohort of 80 neonates was divided into two groups: (1) neonates with PDA and suspicion for CoA requiring observation to confirm the presence or absence of CoA and (2) neonates with PDA and confirmed diagnosis of either CoA or unobstructed aortic arch. Multivariate logistic regression was used to create the coarctation probability model (CPM), which was used to calculate a neonate's probability of CoA. The CPM was validated internally using bootstrapping and subsequently validated prospectively using a "validation" cohort of 74 neonates with PDA.

RESULTS

The CPM had an area under the receiver operating characteristic curve of 0.96 and demonstrated good clinical significance in the risk stratification of neonates with PDA and CoA. No neonate with a CPM probability of <15% had CoA after PDA closure. Neonates with CPM probability < 15% were classified at low risk, between 15% and 60% at moderate risk, and >60% at high risk for CoA.

CONCLUSIONS

On the basis of these results, the authors recommend measurement of the CPM in all neonates with PDA. Those with CPM probability < 15% no longer require observation, which could decrease observation in as many as half of neonates with unobstructed aortic arches; those with CPM probabilities between 15% and 60% require follow-up imaging, while those with CPM probabilities > 60% should be observed as inpatients until PDA closure.

A case of an infant with flail tricuspid valve due to spontaneous papillary muscle rupture: was neonatal lupus the culprit?

A 3-month-old infant presented in extremis with a flail tricuspid valve. The authors theorized that the genesis of her papillary muscle rupture was perinatal ischemia compounded by worsening pulmonary valvular stenosis leading to excessive fiber tension. Her underlying diagnosis of autoimmune-mediated heart block with endocardial fibroelastosis and prenatal glucocorticoid steroid treatment represents potentiating factors.

Pharmacokinetics and safety of intravenously administered citrulline in children undergoing congenital heart surgery: potential therapy for postoperative pulmonary hypertension

OBJECTIVE

Pulmonary hypertension may complicate surgical correction of congenital heart defects, resulting in increased morbidity and mortality. We have previously shown that plasma levels of the nitric oxide precursors citrulline and arginine drop precipitously after congenital cardiac surgery and that oral citrulline supplementation may be protective against the development of pulmonary hypertension. In this study, we assessed the safety and pharmacokinetic profile of intravenous citrulline as a potential therapy for postoperative pulmonary hypertension.

METHODS

The initial phase of this investigation was a dose-escalation study of intravenously administered citrulline in infants and children undergoing one of five congenital cardiac surgical procedures (phase 1). The primary safety outcome was a 20% drop in mean arterial blood pressure from the baseline pressure recorded after admission to the intensive care unit. Based on our previous work, the target circulating plasma citrulline trough was 80 to 100 micromol/L. Each patient was given two separate doses of citrulline: the first in the operating room immediately after initiation of cardiopulmonary bypass and the second 4 hours later in the pediatric intensive care unit. Stepwise dose escalations included 50 mg/kg, 100 mg/kg, and 150 mg/kg. After model-dependent pharmacokinetic analysis, we enrolled an additional 9 patients (phase 2) in an optimized dosing protocol that replaced the postoperative dose with a continuous infusion of citrulline at 9 mg/(kg.h) for 48 hours postoperatively.

RESULTS

The initial stepwise escalation protocol (phase 1) revealed that an intravenous citrulline dose of 150 mg/kg given after initiation of cardiopulmonary bypass yielded a trough level of in the target range of approximately 80 to 100 micromol/L 4 hours later. The postoperative dose revealed that the clearance of intravenously administered citrulline was 0.6 L/(h.kg), with a volume of distribution of 0.9 L/kg and estimated half-life of 60 minutes. Because of the short half-life, we altered the protocol to replace the postoperative dose with a continuous infusion of 9 mg/(kg.h). An additional 9 patients were studied with this continuous infusion protocol (phase 2). Mean plasma citrulline levels were maintained at approximately 125 mumol/L, with a calculated clearance of 0.52 L/(h.kg). None of the 17 patients studied had a 20% drop in mean arterial blood pressure from baseline.

CONCLUSIONS

In this first report of the use of intravenous citrulline in humans, we found citrulline to be both safe and well tolerated in infants and young children undergoing congenital cardiac surgery. Because of the rapid clearance, the optimal dosing regimen was identified as an initial bolus of 150 mg/kg given at the initiation of cardiopulmonary bypass, followed 4 hours later by a postoperative infusion of 9 mg/(kg.h) continued up to 48 hours. Using this regimen, plasma arginine, citrulline, and nitric oxide metabolite levels were well maintained. Intravenous citrulline needs to be studied further as a potential therapy for postoperative pulmonary hypertension.

Modified Norwood operation for hypoplastic left heart syndrome

BACKGROUND

We examined early results in infants with hypoplastic left heart syndrome undergoing the Norwood operation with perioperative use of inhaled nitric oxide and application of extracorporeal membrane oxygenation.

METHODS

Medical records were reviewed retrospectively.

RESULTS

Between April 1997 and March 2001, 50 infants underwent a modified Norwood operation for hypoplastic left heart syndrome. Mean age at operation was 7.5 +/- 5.7 days, and mean weight was 3.1 +/- 0.5 kg. Five infants had a delayed operation because of sepsis. The mean diameter of the ascending aorta by echocardiography was 3.6 +/- 1.8 mm. Ductal cannulation was used to establish cardiopulmonary bypass in all patients. Mean circulatory arrest time was 39.4 +/- 4.8 minutes. The size of the pulmonary-systemic shunt was 3.0 mm in 6 infants, 3.5 mm in 37, and 4.0 mm in 7. Infants with persistent hypoxia (partial pressure of oxygen < 30 mm Hg) received nitric oxide after they were weaned from cardiopulmonary bypass. Extracorporeal membrane oxygenation was initiated in 8 infants in the pediatric intensive care unit primarily for low cardiac output and in 8 in the operating room because of the inability to separate them from cardiopulmonary bypass. The 30-day mortality rate was 22% (11 of 50 patients), and the hospital mortality rate was 32% (16 of 50 patients). Mean follow-up was 17 months. Ten patients (20%) underwent stage-two repair, with one operative death. One survivor had a Fontan procedure, and 2 underwent heart transplantation, with one death.

CONCLUSIONS

Early application of extracorporeal membrane oxygenation for hemodynamic instability and selective use of nitric oxide for persistent hypoxia in the immediate postoperative period may improve survival of patients with hypoplastic left heart syndrome. Renal failure requiring hemofiltration during extracorporeal membrane oxygenation (p < 0.05) and cardiopulmonary arrest in the pediatric intensive care unit (p < 0.05) were predictors of hospital mortality.

Transesophageal echocardiography in pediatric congenital heart disease

The uses of transesophageal echocardiography have expanded dramatically over the last decade. With advances in technology, this imaging modality has become readily available for evaluation of the complex pediatric population with congenital heart disease. This article discusses the many uses of transesophageal echocardiography in this population, in the outpatient setting, in the peri-operative period, and in the cardiac catheterization laboratory.

Mutations in the cardiac transcription factor NKX2.5 affect diverse cardiac developmental pathways

Heterozygous mutations in NKX2.5, a homeobox transcription factor, were reported to cause secundum atrial septal defects and result in atrioventricular (AV) conduction block during postnatal life. To further characterize the role of NKX2.5 in cardiac morphogenesis, we sought additional mutations in groups of probands with cardiac anomalies and first-degree AV block, idiopathic AV block, or tetralogy of Fallot. We identified 7 novel mutations by sequence analysis of the NKX2.5-coding region in 26 individuals. Associated phenotypes included AV block, which was the primary manifestation of cardiac disease in nearly a quarter of affected individuals, as well as atrial septal defect and ventricular septal defect. Ventricular septal defect was associated with tetralogy of Fallot or double-outlet right ventricle in 3 individuals. Ebstein's anomaly and other tricuspid valve abnormalities were also present. Mutations in human NKX2.5 cause a variety of cardiac anomalies and may account for a clinically significant portion of tetralogy of Fallot and idiopathic AV block. The coinheritance of NKX2.5 mutations with various congenital heart defects suggests that this transcription factor contributes to diverse cardiac developmental pathways.

Low incidence of significant valvar insufficiency following retrograde aortic radiofrequency catheter ablation in young patients

The incidence of significant valvar insufficiency at late (<6 month) follow-up was retrospectively evaluated in 27 young patients (age 4. 0-18.0 years) undergoing 29 ablation procedures via the retrograde aortic approach for left-sided accessory connections in whom pre-ablation and post-ablation echocardiograms were available for review. Valvar insufficiency was graded using color flow techniques as absent, trivial, mild, moderate, or severe by blinded reviewers. Ablation was acutely successful via the retrograde approach in 25 of 29 procedures among these 27 patients. Successful ablation was ultimately achieved in all 27 patients. At baseline, 7 patients had evidence of trivial or mild mitral insufficiency, and no patient had aortic insufficiency. Three patients had evidence of impaired left ventricular systolic performance in the presence of manifest pre-excitation. At follow-up, pre-existing mitral insufficiency resolved in 5/7 patients, and persisted in 2 patients. New mitral insufficiency was evident in 3 patients, and new aortic insufficiency was transiently evident in 1 patient following ablation (all trivial). Institutional experience (mean rank 10 cases vs. 33 cases, p <.0005), and lower patient weight (29.7 vs. 56.3 kilograms, p =.01) were the only factors associated with the development of new valvar insufficiency. Valvar insufficiency could not be detected by careful auscultation in any patient and was deemed clinically insignificant in all patients. We conclude that ablation of left-sided accessory connections can be performed via the retrograde aortic approach without creating clinically significant valvar insufficiency.

Endocarditis caused by group A beta-hemolytic Streptococcus in an infant: case report and review

Acute bacterial endocarditis in the absence of underlying heart disease is rare. We report the occurrence of endocarditis caused by group A beta-hemolytic Streptococcus (GABHS), following varicella, in a 5-month-old child without heart disease. In addition to this child, seven other children with endocarditis caused by GABHS have been reported since 1966, six of whom did not have preexisting heart disease. In one of these children, GABHS endocarditis was preceded by varicella. These cases indicate that GABHS is capable of causing endocarditis in the absence of heart disease, and they provide further evidence that varicella is an important risk factor for invasive GABHS infections.

Hypoplastic left heart syndrome: anesthetic care prior to transplantation or surgical palliation

Hypoplastic left heart syndrome is the most common lethal cardiac defect in neonates. Options for treatment include cardiac transplantation and surgical palliation. When cardiac transplantation is chosen as the preferred option, a considerable delay may occur until a suitable donor is available. During this time, anesthetic care may be required for various surgical procedures. Associated anomalies seen in these infants and the anesthetic implications imposed by the abnormal cardiac anatomy are discussed.

Noninvasive assessment of myocardium at risk by Tl-201 SPECT imaging in a child with Kawasaki disease. A case report

Serial two-dimensional echocardiograms documented the formation of giant aneurysms, measuring from 0.55 to 3.1 cm in diameter, in the distribution of the left and right coronary arteries, in a 2 1/2-year-old boy with Kawasaki disease. His global left ventricular function, assessed by M-mode echocardiography, was normal, and no significant wall motion abnormalities could be detected on two-dimensinal evaluation. Cardiac catheterization showed multiple aneurysms with no evidence of stenosis. Although he had no clinical symptoms or electrocardiographic evidence of ischemia, pharmacologic stress and delayed Tl-201 SPECT images revealed prominent stress-induced myocardial ischemia in the left ventricle. A resting gated blood pool study showed hypokinesia in corresponding regions of the left ventricle. This case demonstrates the usefulness of Tl-201 myocardial SPECT imaging and resting gated blood pool studies in the management of coronary artery disease in children with Kawasaki disease.

Acute infantile cardiomyopathy as a presenting feature of mucopolysaccharidosis VI

An infant with a diagnosis of acute infantile cardiomyopathy was subsequently shown to have mucopolysaccharidosis VI. The mucopolysaccharidoses should be included in the differential diagnosis of infantile cardiomyopathy.