Active versus restrictive ligation strategy for patent ductus arteriosus - A retrospective two-center study of extremely preterm infants born between 22 + 0 and 25 + 6 weeks of gestational age

BACKGROUND

Patent ductus arteriosus (PDA) in premature infants is associated with adverse clinical outcomes. Mode and timing of treatment are still controversial. Data are limited in the most extremely premature infants <26 weeks of gestational age (GA), where clinical problems are most significant and patients are most vulnerable.

AIMS

To investigate whether different approaches to surgical closure of PDA in two large Swedish centers has an impact on clinical outcomes including mortality in extremely preterm infants born <26 weeks GA.

STUDY DESIGN

Retrospective, two-center, cohort study.

SUBJECTS

Infants born at 22+0-25+6 weeks GA between 2010 and 2016 at Uppsala University Children's Hospital (UUCH; n = 228) and Queen Silvia Children's Hospital Gothenburg (QSCHG; n = 220).

MAIN OUTCOME MEASURES

Survival, bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP).

RESULTS

Surgical closure of PDA was more common and performed earlier at QSCHG (50 % vs 16 %; median age 11 vs 44 days; p < 0.01). Survival was similar in both centres. There was a higher incidence of severe BPD and longer duration of mechanical ventilation at UUCH (p < 0.01). There was a higher incidence of ROP, IVH and sepsis at QSCH (p < 0.05, p < 0.01 and p < 0.01). A sub-group analysis matching all surgically treated infants at QSCHG with infants at UUCH with the same GA showed similar results as the total cohort.

CONCLUSION

Earlier and higher rate of surgical PDA closure in this cohort of extremely preterms born <26 weeks GA did not impact mortality but was associated with lower rates of severe BPD and higher rates of severe ROP.

Screening for Critical Congenital Heart Defects in Sweden

OBJECTIVES

Early diagnosis of critical congenital heart defects (CCHD) improves survival. We evaluated the relative contributions of prenatal ultrasound, neonatal pulse oximetry screening (POS), and neonatal physical examination (NPE) to the early detection (before discharge) of CCHD in the context of increasing prenatal detection, and POS being a national standard since 2013.

METHODS

Retrospective, nationwide population-based study. All full-term live-born infants with CCHD in Sweden between 2014 and 2019 were included. CCHD was defined as a congenital heart defect requiring surgery or catheter-based intervention or resulting in death within 28 days of birth.

RESULTS

Of 630 infants, 89% were diagnosed before discharge or death, 42% prenatally, 11% from early symptoms, 23% by POS, and 14% from NPE after a negative POS. Four (0.6%) died undiagnosed before discharge and 64/630 (10%) were discharged undiagnosed, with 24/64 being readmitted with circulatory failure and causing 1 preoperative death. Coarctation was the most prevalent CCHD (N = 184), 25% of whom were detected prenatally (12% by POS and 29% by NPE). Two died undiagnosed before discharge and 30% were discharged undiagnosed. Transposition was the second most common defect (N = 150) and 43% were detected prenatally (33% by POS, 1 by NPE) and 2 died undiagnosed before POS. None was discharged undiagnosed.

CONCLUSIONS

POS and NPE remain important for the early detection of CCHD complementing prenatal ultrasound screening. Nevertheless, 1 in 10 with CCHD leaves the hospital without a diagnosis, with coarctation being the predominant lesion. Future research on CCHD screening should have a particular focus on this cardiac defect.

Impact of Left Ventricular Morphology on Adverse Outcomes Following Stage 1 Palliation for Hypoplastic Left Heart Syndrome: 20 Years of National Data From Sweden

Background

Hypoplastic left heart syndrome is associated with significant morbidity and mortality. We aimed to assess the influence of left ventricular morphology and choice of shunt on adverse outcome in patients with hypoplastic left heart syndrome and stage 1 palliation.

Methods and Results

This was a retrospective analysis of patients with hypoplastic left heart syndrome with stage 1 palliation between 1999 and 2018 in Sweden. Patients (n=167) were grouped based on the anatomic subtypes aortic‐mitral atresia, aortic atresia‐mitral stenosis (AA‐MS), and aortic‐mitral stenosis. The left ventricular phenotypes including globular left ventricle (Glob‐LV), miniaturized and slit‐like left ventricle (LV), and the incidence of major adverse events (MAEs) including mortality were assessed. The overall mortality and MAEs were 31% and 41%, respectively. AA‐MS (35%) was associated with both mortality (all other subtypes versus AA‐MS: interstage‐I: hazard ratio [HR], 2.7; P =0.006; overall: HR, 2.2; P =0.005) and MAEs (HR, 2.4; P =0.0009). Glob‐LV (57%), noticed in all patients with AA‐MS, 61% of patients with aortic stenosis‐mitral stenosis, and 19% of patients with aortic atresia‐mitral atresia, was associated with both mortality (all other left ventricular phenotypes versus Glob‐LV: interstage‐I: HR, 4.5; P =0.004; overall: HR, 3.4; P =0.0007) and MAEs (HR, 2.7; P =0.0007). There was no difference in mortality and MAEs between patients with AA‐MS and without AA‐MS with Glob‐LV ( P >0.15). Patients with AA‐MS (35%) or Glob‐LV (38%) palliated with a Blalock‐Taussig shunt had higher overall mortality compared with those palliated with Sano shunts, irrespective of the stage 1 palliation year (AA‐MS: HR, 2.6; P =0.04; Glob‐ LV: HR, 2.1; P =0.03).

Conclusions

Glob‐LV and AA‐MS are independent morphological risk factors for adverse short‐ and long‐ term outcome, especially if a Blalock‐Taussig shunt is used as part of stage 1 palliation. These findings are important for the clinical management of patients with hypoplastic left heart syndrome.

Prenatal detection of congenital heart disease - results of a Swedish screening program 2013-2017

Background

This report evaluates results of a screening program on prenatal detection of congenital heart defects in a geographical cohort of western Sweden between January 1st, 2013 and June 31st, 2017. During the study period 88,230 children were born in VGR.

Methods

Retrospective data on pregnant women from the Västra Götaland region that were referred to fetal cardiologists in Gothenburg were retrieved. To determine prenatal detection rate, all neonates who underwent surgery or catheter intervention for a critical congenital heart defect born between January 1st, 2014 and December 31st, 2016 were included. The four-chamber view was implemented into the routine scan in 2009 and implementation of the ISUOG guidelines, including the outflow tracts, started in the region in 2015.

Results

113 fetuses received a prenatal diagnosis of a major congenital heart defect. 89% of these were referred because of a suspected cardiac malformation and 88% were diagnosed before 22 completed weeks. 59% of the patients diagnosed before 22 completed weeks opted for termination of pregnancy. During 2014–2016, 61 fetuses had a prenatal diagnosis of a critical congenital heart defect and a further 47 were diagnosed after birth, hence 56% were diagnosed prenatally, 82% for those which had a combination with an extracardiac abnormality and/or chromosomal aberration compared to 50% if an isolated critical congenital heart defect was diagnosed. For single ventricle cardiac defects such as hypoplastic left heart syndrome, double inlet left ventricle and tricuspid atresia, the detection rate was 100%. The detection rate for transposition of the great arteries and coarctation of the aorta was 9 and 18% respectively.

Conclusions

56% of all fetuses with a critical congenital heart defect were diagnosed prenatally during 2014–2016 and approximately 53% of all major congenital heart defects 2013–2017 as compared to 13.8% in 2009 in the same region. An increased focus towards the fetal heart in the routine scan improved the prenatal detection rate of major congenital heart defects. The detection of congenital heart defects affecting the four-chamber view seems sufficient, but more training is needed to improve the quality of the examination of the outflow tracts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04028-5.

Low false-positive rate of perfusion index as a screening tool for neonatal aortic coarctation

Aim

Adding perfusion index (PI) to pulse oximetry screening (POS) may increase neonatal detection of CoA (aortic coarctation). A cut‐off <0.7% has been suggested but is associated with a high rate of false positives. We aimed to evaluate the specificity of PI when using repeated instead of single measurements.

Methods

A pilot study was conducted in 50 neonates. PI was recorded in right hand and a foot by pulse oximeter. If PI was <0.7%, the measurement was immediately repeated up to 3 times. If all three measurements were <0.7% in hand and/or foot the screen was positive and echocardiography was performed. There were 3/50 false‐positive screens. The protocol was therefore modified requiring 30 min intervals between measurements.

Results

An additional 463 neonates were included using the modified protocol at a median age of 18 h. There were no false positives. The only neonate with CoA had a negative screen (PI hand 1.2% and foot 0.8%). The measurement required on average an extra 3 min and 30 s compared with POS only.

Conclusion

The false‐positive rate of PI was reduced by using repeated PI measurements. The sensitivity for CoA using this protocol should be evaluated in large‐scale prospective studies.

Low risk of necrotising enterocolitis in enterally fed neonates with critical heart disease: an observational study

OBJECTIVE

We aimed to investigate the frequency of necrotising enterocolitis (NEC) in infants with critical congenital heart disease (CCHD) hypothesising that preoperative enteral feeding does not increase the risk of NEC.

BACKGROUND

When NEC affects term infants, underlying risk factors such as asphyxia, sepsis or CCHD are often found. Due to fear of NEC development in infants with CCHD great caution is practised in many countries to defer preoperative enteral feeding, but in Sweden this is routinely provided.

DESIGN, SETTING AND PATIENTS

An observational study of all infants born with CCHD who were admitted to Queen Silvia Children's Hospital in Gothenburg between 2010 and 2017. The International Classification of Diseases 10th Revision diagnosis code of NEC was used to identify NEC cases in this group. Infants described as 'fully fed' or who were fed at least 45 mL/kg/day before cardiac surgery were identified.

MAIN OUTCOME MEASURES

NEC in infants with CCHD in relation to preoperative enteral feeding.

RESULTS

There were 458 infants with CCHD admitted during the study period. 408/458 were born at term and 361/458 required prostaglandin E1 before surgery. In total, 444/458 infants (97%) were fully fed or fed at least 45 mL/kg daily before cardiac surgery. Four of 458 infants developed NEC (0.9%). All four had other risk factors for NEC.

CONCLUSIONS

This study showed a low risk of NEC in term infants fed enterally before cardiac surgery. We speculate that preoperative enteral feeding of neonates with CCHD does not increase the risk of NEC development.

Echocardiographic Predictors of Recoarctation After Surgical Repair: A Swedish National Study

BACKGROUND

After surgical repair of aortic coarctation (CoA) there is a risk for restenosis (reCoA), particularly in the first year of life. This study aimed to identify reCoA risk factors by analyzing postoperative predischarge echocardiograms.

METHODS

This was a retrospective analysis of echocardiograms of children born operated on for CoA in Sweden in 2011 to 2017.

RESULTS

A total of 253 children were included. Median age at surgery was 10 days; median follow-up was 4.6 years. Risk for restenosis occurred in 34 patients (13%; 74% by 6 months and 91% by 12 months). We generated 2 reCoA risk models applying aortic dimensions and the respective Z-scores combined with surgical and demographic factors. We defined reCoA risk categories as low (≤10%), moderate (11% to 29%), moderate to high (30% to 49%), or high (≥50%). Patients with either isthmus of 3.3 mm or less (1- and 5-year event-free survival of 38% and 32%, respectively) or isthmus Z-score of -2.8 or less with a weight at surgery of less than 4.4 kg (1- and 5-year event free survival of 21% and 16%, respectively) were at highest risk for reCoA. Conversely, patients at low risk had isthmus greater than 3.7 mm and distal aortic arch greater than 3.5mm (1- and 5-year event free survival of 97% and 97%, respectively), and isthmus and proximal aortic arch Z-score greater than -2.8 or operative weight greater than 4.4 kg with an isthmus Z-score of -2.8 or less (1- and 5-year event-free survival of 97% and 97%, respectively).

CONCLUSIONS

Risk for reCoA can be predicted based on postoperative predischarge echocardiographic variables combined with surgical and demographic factors. We suggest tailoring follow-up intervals individually according to the predicted reCoA risk.

Changing Epidemiology of Hypoplastic Left Heart Syndrome: Results of a National Swedish Cohort Study

Background Norwood surgery provides a palliative surgical option for hypoplastic left heart syndrome and has been available in Sweden since 1993. The practice of prenatal ultrasound screening was gradually implemented in the same era, resulting in an increased prenatal detection rate. Our primary aims were to study changes in the incidence of live births, prenatal detection rate, and the termination of pregnancies over time. The secondary aims were to study the proportion of live-borns undergoing surgery and to identify factors that influenced whether surgery was or was not performed. Methods and Results Neonates with hypoplastic left heart syndrome with aortic atresia born 1990-2010 were identified through national databases, surgical files, and medical records. The fetal incidence was estimated from the period when prenatal screening was rudimentary. The study period was divided into the presurgical, early surgical, and late surgical periods. The incidence was calculated as the overall yearly incidence for each time period and sex separately. Factors influencing whether surgery was performed were analyzed using Cox-logistic regression. The incidence at live birth decreased from 15.4 to 8.4 per 100 000. The prenatal detection rate increased from 27% to 63%, and terminations increased from 19% to 56%. The odds of having surgery was higher in the late period and higher in the group with prenatal diagnosis. Conclusions We observed a decrease in incidence of live-borns with hypoplastic left heart syndrome aortic atresia. There was in increase in prenatal detection rate and an increase in termination of pregnancy. The proportion of live-borns who underwent surgery increased between time periods.

Fetal hemodynamic response to aortic valvuloplasty and postnatal outcome: a European multicenter study

OBJECTIVE

Fetal aortic stenosis may progress to hypoplastic left heart syndrome. Fetal valvuloplasty (FV) has been proposed to improve left heart hemodynamics and maintain biventricular (BV) circulation. The aim of this study was to assess FV efficacy by comparing survival and postnatal circulation between fetuses that underwent FV and those that did not.

METHODS

This was a retrospective multicenter study of fetuses with aortic stenosis that underwent FV between 2005 and 2012, compared with contemporaneously enrolled natural history (NH) cases sharing similar characteristics at presentation but not undergoing FV. Main outcome measures were overall survival, BV-circulation survival and survival after birth. Secondary outcomes were hemodynamic change and left heart growth. A propensity score model was created including 54/67 FV and 60/147 NH fetuses. Analyses were performed using logistic, Cox or linear regression models with inverse probability of treatment weighting (IPTW) restricted to fetuses with a propensity score of 0.14-0.9, to create a final cohort for analysis of 42 FV and 29 NH cases.

RESULTS

FV was technically successful in 59/67 fetuses at a median age of 26 (21-34) weeks. There were 7/72 (10%) procedure-related losses, and 22/53 (42%) FV babies were delivered at < 37 weeks. IPTW demonstrated improved survival of liveborn infants following FV (hazard ratio, 0.38; 95% CI, 0.23-0.64; P = 0.0001), after adjusting for circulation and postnatal surgical center. Similar proportions had BV circulation (36% for the FV cohort and 38% for the NH cohort) and survival was similar between final circulations. Successful FV cases showed improved hemodynamic response and less deterioration of left heart growth compared with NH cases (P ≤ 0.01).

CONCLUSIONS

We report improvements in fetal hemodynamics and preservation of left heart growth following successful FV compared with NH. While the proportion of those achieving a BV circulation outcome was similar in both cohorts, FV survivors showed improved survival independent of final circulation to 10 years' follow-up. However, FV is associated with a 10% procedure-related loss and increased prematurity compared with the NH cohort, and therefore the risk-to-benefit ratio remains uncertain. We recommend a carefully designed trial incorporating appropriate and integrated fetal and postnatal management strategies to account for center-specific practices, so that the benefits achieved by fetal therapy vs surgical strategy can be demonstrated clearly. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Natural history of 107 cases of fetal aortic stenosis from a European multicenter retrospective study

OBJECTIVES

Fetal aortic valvuloplasty (FV) aims to prevent fetal aortic valve stenosis progressing into hypoplastic left heart syndrome (HLHS), which results in postnatal univentricular (UV) circulation. Despite increasing numbers of FVs performed worldwide, the natural history of the disease in fetal life remains poorly defined. The primary aim of this study was to describe the natural history of fetal aortic stenosis, and a secondary aim was to test previously published criteria designed to identify cases of emerging HLHS with the potential for a biventricular (BV) outcome after FV.

METHODS

From a European multicenter retrospective study of 214 fetuses with aortic stenosis (2005-2012), 107 fetuses in ongoing pregnancies that did not undergo FV were included in this study and their natural history was reported. We examined longitudinal changes in Z-scores of aortic and mitral valve and left ventricular dimensions and documented direction of flow across the foramen ovale and aortic arch, and mitral valve inflow pattern and any gestational changes. Data were used to identify fetuses satisfying the Boston criteria for emerging HLHS and estimate the proportion of these that would have been ideal FV candidates. We applied the threshold score whereby a score of 1 was assigned to fetuses for each Z-score meeting the following criteria: left ventricular length and width > 0; mitral valve diameter > -2; aortic valve diameter > -3.5; and pressure gradient across either the mitral or aortic valve > 20 mmHg. We compared the predicted circulation with known survival and final postnatal circulation (BV, UV or conversion from BV to UV).

RESULTS

Among the 107 ongoing pregnancies there were eight spontaneous fetal deaths and 99 livebirths. Five were lost to follow-up, five had comfort care and four had mild aortic stenosis not requiring intervention. There was intention-to-treat in these 85 newborns but five died prior to surgery, before circulation could be determined, and thus 80 underwent postnatal procedures with 44 BV, 29 UV and seven BV-to-UV circulatory outcomes. Of newborns with intention-to-treat, 69/85 (81%) survived ≥ 30 days. Survival at median 6 years was superior in cases with BV circulation (P = 0.041). Those with a postnatal UV circulation showed a trend towards smaller aortic valve diameters at first scan than did the BV cohort (P = 0.076), but aortic valve growth velocities were similar in both cohorts to term. In contrast, the mitral valve diameter was significantly smaller at first scan in those with postnatal UV outcomes (P = 0.004) and its growth velocity (P = 0.008), in common with the left ventricular inlet length (P = 0.004) and width (P = 0.002), were reduced significantly by term in fetuses with UV compared with BV outcome. Fetal data, recorded before 30 completed gestational weeks, from 70 treated neonates were evaluated to identify emerging HLHS. Forty-four had moderate or severe left ventricular depression and 38 of these had retrograde flow in the aortic arch and two had left-to-right flow at atrial level and reversed a-waves in the pulmonary veins. Thus 40 neonates met the criteria for emerging HLHS and BV circulation was documented in 13 (33%). Of these 40 cases, 12 (30%) had a threshold score of 4 or 5, of which five (42%) had BV circulation without fetal intervention.

CONCLUSIONS

The natural history in our cohort of fetuses with aortic stenosis and known outcomes shows that a substantial proportion of fetuses meeting the criteria for emerging HLHS, with or without favorable selection criteria for FV, had a sustained BV circulation without fetal intervention. This indicates that further work is needed to refine the selection criteria to offer appropriate therapy to fetuses with aortic stenosis. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Persistent reduced myocardial deformation in neonates after CoA repair

INTRODUCTION

Surgical repair of coarctation of the aorta (CoA) is a safe procedure in children, however the condition is known for its potential recurrence and other related complications. The available evidence shows abnormal intrinsic properties of the aorta in CoA, thus suggesting additional effect, even after CoA repair, on left ventricular (LV) function. Accordingly, we sought to obtain a better understanding of LV myocardial mechanics in very early-corrected CoA using two-dimensional STE.

METHODS AND RESULTS

We retrospectively studied 21 patients with corrected CoA at a median age of 9 (2-53) days at three time points: 1) just before intervention, 2) at short-term follow-up and 3) at medium-term follow-up after intervention and compared them with normal values. Speckle tracking analysis was conducted via vendor independent software, Tomtec. After intervention, LV function significantly improved (from -12.8±3.9 to -16.7±1.7; p<0.001), however normal values were not reached even at medium term follow-up (-18.3±1.7 vs. -20±1.6; p=0.002). Medium term longitudinal strain correlated with pre intervention EF (r=0.58, p=0.006). Moreover, medium term subnormal values were more frequently associated with bicuspid aortic valve (33.3% vs. 66.6%; p<0.05).

CONCLUSION

LV myocardial function in neonates with CoA can be feasibly evaluated and followed up by speckle tracking echocardiography. LV subendocardial dysfunction however, remains in early infancy coarctation long after repair. Long-term follow-up through adulthood using myocardial deformation measurements should shed light on the natural history and consequences of this anomaly.

Foetal tachyarrhythmia treatment remains challenging even if the vast majority of cases have a favourable outcome

AIM

The optimal treatment for foetal tachyarrhythmia remains controversial, and this study aimed to fill this gap in the knowledge.

METHODS

We retrospectively reviewed all cases of foetal tachyarrhythmia diagnosed at two tertiary foetal cardiology centres in Sweden from 1990 to 2012.

RESULTS

Of the 153 cases, 28% had atrial flutter (AF), 63% had atrioventricular reentrant tachycardia (AVRT) and 9% had other mechanisms. Hydrops was present in 45, less frequently in AF than in AVRT. Transplacental treatment was commenced in 99 and the rhythm normalised in two-thirds, without any significant difference in cardioversion rates between AF and AVRT cases or nonhydropic and hydropic foetuses. Sotalol treatment had a higher cardioversion rate than digoxin in AVRT (63% versus 33%, p < 0.05) but not in AF (57% versus 56%). Two or more drugs were used in 38%. Neonatal survival was 100% in nonhydropic and 84% in hydropic cases. After a median of eight years, 11/134 patients still had arrhythmias, one had died due to arrhythmia and another had undergone cardiac transplantation.

CONCLUSION

Transplacental treatment was frequently insufficient to obtain cardioversion in nonhydropic and hydropic foetuses, but all nonhydropic cases had favourable outcomes. Larger prospective studies are needed to optimise the treatment of cases with hydrops.

Parent's experiences of counselling and their need for support following a prenatal diagnosis of congenital heart disease--a qualitative study in a Swedish context

BACKGROUND

Prenatal screening for foetal cardiac abnormalities has been increasingly practiced in Sweden during the last 25 years. A prenatal diagnosis may have medical benefits but may also cause sustained parental psychological distress. The aim of this study was to explore pregnant women's, and their partner's, experiences of counselling and need for support during continued pregnancy following a prenatal diagnosis of a cardiac defect. A second aim was to use this information to propose a structured follow-up programme for continued support after the first counselling.

METHOD

DESIGN

Qualitative study, using interviews performed 5-9 weeks after a prenatal diagnosis of congenital heart disease.

SETTING

A tertiary foetal cardiology unit in Sweden Sample: Six pregnant women and their 6 partners, consecutively recruited after a prenatal diagnosis of an isolated and significant cardiac defect.

DATA ANALYSIS

Qualitative content analysis.

RESULTS

The analysis resulted in three themes. 1/ Counselling and making a decision--the importance of knowledge and understanding: Short waiting time for specialist evaluation together with clear and straightforward information was essential. Parents called for written information together with a high-quality website with relevant information about congenital heart disease. 2/ Continued support during pregnancy: Continued and easy access to health care professionals, including a paediatric specialist nurse, throughout pregnancy, was important. Contact with couples with similar experiences and social media were also considered valuable sources of support. 3/ Next step--the near future: Practical and economical issues during the postnatal hospital stay and the initial period following the hospital stay were common concerns.

CONCLUSIONS

The following aspects should be considered in a structured follow up program during pregnancy after a prenatal diagnosis of CHD; written information, access to a safe web-site with information of high quality in their native language, support from parents with similar experiences and continued contact with a specialist liaison nurse with experience of paediatric cardiology.

Late Diagnosis of Coarctation Despite Prenatal Ultrasound and Postnatal Pulse Oximetry

OBJECTIVES

To determine what contribution prenatal ultrasound screening and neonatal pulse oximetry screening (POS) make to the timely diagnosis of neonatal coarctation of the aorta (CoA).

METHODS

We identified infants and fetuses diagnosed with isolated CoA in our referral area between 2003 and 2012 who died without surgery, underwent surgical repair before 2 months of age, or were terminated after a prenatal diagnosis. Clinical data were collected from hospital charts.

RESULTS

Only 3 of the 90 cases were diagnosed prenatally. Two of the 3 were born alive and in 1 case the couple opted for termination of pregnancy. Nineteen of the remaining 87 cases were born in units that used POS (hand and foot) and 4 of 19 screened positive. Of the remaining 83 cases, 46 were discharged undiagnosed (7 after nondiagnostic echocardiography), including 9 with a murmur and weak femoral pulses and 8 with a murmur and normal pulses. One was diagnosed postmortem after dying at home, and 22 of the remaining 45 discharged infants were in circulatory failure on readmission. Five of the patients who were not discharged died without surgery and undiagnosed CoA was the most probable cause of death in 2 of these patients.

CONCLUSIONS

The contribution of prenatal ultrasound screening and postnatal POS to the timely diagnosis of CoA was low. Careful physical examination of all newborns therefore continues to play a fundamental role in detecting this life-threatening cardiac defect, and better screening methods need to be developed.

Pulse oximetry screening and prenatal diagnosis play complementary roles in reducing risks in simple transposition of the great arteries

AIM

This study quantified the contribution of pulse oximetry screening to an early diagnosis of simple transposition. We also estimated the proportion of neonates with this life-threatening cardiac defect who could benefit from prenatal diagnosis, even when pulse oximetry screening had been implemented.

METHODS

This population-based, retrospective, cohort study of cases born from 2003 to 2013 used data from surgical files, the Swedish Causes of Death Registry and the National Forensic Medicine database. The main outcome measures were early postnatal circulatory instability, pre-operative death, neurological morbidity and risk of discharge before diagnosis.

RESULTS

We identified 89 cases, including three diagnosed prenatally. Hospitals using pulse oximetry screening diagnosed all 31 neonates before discharge, including seven as a result of screening, but 10 of 55 infants in the nonscreening hospitals were discharged undiagnosed (p = 0.017). Prenatal diagnosis could have decreased the risk of early circulatory instability, pre-operative death or neurological morbidity in 12 of the 72 infants born in referring hospitals (17%). There was one pre-operative death and no postoperative deaths at a mean follow-up of 4.7 years.

CONCLUSION

Pulse oximetry screening minimised the risk of discharging infants with transposition, but prenatal diagnosis would have been necessary to avoid early circulatory instability in 17% of cases.

Fetal aortic valvuloplasty: investigating institutional bias in surgical decision-making

OBJECTIVES

Fetal aortic valvuloplasty may prevent the progression of aortic stenosis to hypoplastic left heart syndrome and allow biventricular rather than univentricular postnatal treatment. This study aimed to investigate whether blinded simulation of a multidisciplinary team approach aids interpretation of multicenter data to uncover institutional bias in postnatal decision-making following fetal cardiac intervention for aortic stenosis.

METHODS

The study included 109 cases of prenatally diagnosed aortic stenosis from 13 European countries, of which 32 had undergone fetal cardiac intervention. The multidisciplinary team, blinded to fetal cardiac intervention, institutional location and postnatal treatment, retrospectively assigned a surgical pathway (biventricular or univentricular) based on a review of recorded postnatal imaging and clinical characteristics. The team's decisions were the numerical consensus of silent voting, with case review when a decision was split. Funnel plots showing concordance between the multidisciplinary team and the local team's surgical choice (first pathway) and with outcome (final pathway) were created.

RESULTS

In 105 cases the multidisciplinary team reached a consensus decision regarding the surgical pathway, with no decision in four cases because the available imaging records were inadequate. Blinded multidisciplinary team consensus for the first pathway matched the decision of the surgical center in 93/105 (89%) cases, with no difference in agreement between those that had undergone successful fetal cardiac intervention (n = 32) and no (n = 74) or unsuccessful (n = 3) valvuloplasty (no fetal cardiac intervention) (κ = 0.73 (95% CI, 0.38-1.00) vs 0.74 (95% CI, 0.51-0.96)). However, funnel plots comparing multidisciplinary team individual decisions with those of the local teams displayed more discordance (meaning biventricular-univentricular conversion) for the final surgical pathway following fetal cardiac intervention than they did for cases without such intervention (36/74 vs 34/130; P = 0.002), and identified one outlying center.

CONCLUSIONS

The use of a blinded multidisciplinary team to simulate decision-making and presentation of data in funnel plots may assist in the interpretation of data submitted to multicenter studies and permit the identification of outliers for further investigation. In the case of aortic stenosis, a high level of agreement was observed between the multidisciplinary team and the surgical centers, but one outlying center was identified.

Nordic pulse oximetry screening--implementation status and proposal for uniform guidelines

Aim

Pulse oximetry screening of newborn infants increases early detection of critical congenital heart disease and minimises the risk of circulatory collapse before surgery. This study provides an update on the implementation of pulse oximetry screening in the Nordic countries and proposes standardised guidelines.

Methods

A questionnaire exploring pulse oximetry screening, clinical examination routines and availability of echocardiography was distributed to all 157 delivery units in the Nordic countries in June 2013.

Results

We received responses from 156 of the 157 delivery units, and 116 (74%) were using pulse oximetry screening by September 2013. Preductal and postductal screening were both used in 59 of 116 units (51%), with just postductal screening in 51 of 116 (44%) and just preductal screening alone in 6 of 116 (5%). Screening was performed before 24 h in 105 of 116 units (91%). The implementation of screening was highest in Finland (29/30, 97%), Sweden (42/46, 91%) and Norway (43/48, 90%) and lowest in Denmark (2/24, 8%) and Iceland (0/8 units).

Conclusion

In Sweden, Norway and Finland, the implementation of pulse oximetry screening is currently the highest in the world and coverage will be close to 100% in 2014. We propose uniform Nordic guidelines using preductal and postductal screening before 24 h of age.

Total anomalous pulmonary venous connection: impact of prenatal diagnosis

OBJECTIVES

To investigate whether prenatal screening is effective in the detection of total anomalous pulmonary venous connection (TAPVC) and to identify common prenatal features.

METHODS

This was a retrospective collaborative study involving 19 pediatric cardiac centers in the UK, Ireland and Sweden. Cases with TAPVC born between January 1, 1998 and December 31, 2004, and prenatally diagnosed cases whose estimated dates of delivery were within this time frame, were identified. Cases with functionally univentricular circulation or atrial isomerism were excluded. All available data and stored images were reviewed.

RESULTS

Four-hundred and twenty-four cases with TAPVC were identified prenatally or postnatally, of whom eight (1.9%) had a prenatal diagnosis of TAPVC. Median gestational age at fetal diagnosis was 26 + 6 (range, 22 + 4 to 32 + 0) weeks. Six further fetuses with TAPVC had an abnormality diagnosed on prenatal ultrasound, but not the TAPVC. This included other congenital heart defects (four cases) and isolated pleural effusion (two cases). Seventeen (4.0%) of the 422 liveborn infants had a first-degree relative with congenital heart disease; and six of 17 had a sibling with TAPVC. Two died in utero. Of the liveborn infants diagnosed prenatally with TAPVC, none required urgent intervention for pulmonary venous obstruction and all were alive and well at a median of 2.3 (range, 1.0-7.0) years after surgical repair.

CONCLUSION

Prenatal diagnosis of TAPVC is infrequent using current screening methods. Where there is a family history of TAPVC, specialized fetal echocardiography at 20 and 28 weeks' gestation may be indicated.

A population-based investigation of the autoantibody profile in mothers of children with atrioventricular block

The objective of the study was to investigate the antigen specificity and occurrence of individual autoantibodies in mothers of children diagnosed with atrioventricular (AV) block in a nation-wide setting. Patients with AV block detected before 15 years of age were identified using national quality registries as well as a network of pediatric and adult cardiologists and rheumatologists at the six university hospitals in Sweden. Patients with gross heart malformations, surgically or infectiously induced blocks were excluded. Blood samples were obtained from the mothers and maternal autoantibody profile, including the occurrence of antibodies against Ro52, Ro60, La, SmB, SmD, RNP-70k, RNP-A, RNP-C, CENP-C, Scl-70, Jo-1, ribosomal RNP and histones was investigated in 193 mothers of children with AV block by immunoblotting and ELISA. Autoantibody reactivity was detected in 48% (93/193) of the mothers of children with AV block. In autoantibody-positive mothers, the vast majority, 95% (88/93), had antibodies against Ro52, while 63% (59/93) had autoantibodies to Ro60 and 58% (54/93) had autoantibodies to La. In addition, 13% (12/93) of the autoantibody-positive mothers had antibodies to other investigated antigens besides Ro52, Ro60 and La, and of these anti-histone antibodies were most commonly represented, detected in 8% (7/93) of the mothers. In conclusion, this Swedish population-based study confirms that maternal autoantibodies may associate with heart block in the child. Further, our data demonstrate a dominant role of Ro52 antibodies in association with AV block.

Isolated Atrioventricular Block in the Fetus

Background—

Isolated complete atrioventricular block in the fetus is a rare but potentially lethal condition in which the effect of steroid treatment on outcome is unclear. The objective of this work was to study risk factors associated with death and the influence of steroid treatment on outcome.

Methods and Results—

We studied 175 fetuses diagnosed with second- or third-degree atrioventricular block (2000–2007) retrospectively in a multinational, multicenter setting. In 80% of 162 pregnancies with documented antibody status, atrioventricular block was associated with maternal anti-Ro/SSA antibodies. Sixty-seven cases (38%) were treated with fluorinated corticosteroids for a median of 10 weeks (1–21 weeks). Ninety-one percent were alive at birth, and survival in the neonatal period was 93%, similar in steroid-treated and untreated fetuses, regardless of degree of block and/or presence of anti-Ro/SSA. Variables associated with death were gestational age <20 weeks, ventricular rate ≤50 bpm, fetal hydrops, and impaired left ventricular function at diagnosis. The presence of ≥1 of these variables was associated with a 10-fold increase in mortality before birth and a 6-fold increase in the neonatal period independently of treatment. Except for a lower gestational age at diagnosis in treated than untreated (23.4±2.9 versus 24.9±4.9 weeks; P =0.02), risk factors were distributed equally between treatment groups. Two-thirds of survivors had a pacemaker by 1 year of age; 8 children developed cardiomyopathy.

Conclusions—

Risk factors associated with a poor outcome were gestation <20 weeks, ventricular rate ≤50 bpm, hydrops, and impaired left ventricular function. No significant effect of treatment with fluorinated corticosteroids was seen.

Development of heart block in children of SSA/SSB-autoantibody-positive women is associated with maternal age and displays a season-of-birth pattern

OBJECTIVE

Congenital heart block may develop in the fetuses of Ro/SSA-positive and La/SSB-positive mothers. Recurrence rates of only 10-20% despite persisting maternal antibodies indicate that additional factors are critical for the establishment of heart block. The authors investigated the influence of other maternal and fetal factors on heart block development in a Swedish population-based cohort.

METHODS

The influence of fetal gender, maternal age, parity and time of birth on heart block development was analysed in 145 families, including Ro/La-positive (n=190) and Ro/La-negative (n=165) pregnancies.

RESULTS

There was a recurrence rate of 12.1% in Ro/La-positive women, and no recurrence in Ro/La-negative women. Fetal gender and parity did not influence the development of heart block in either group. Maternal age in Ro/La-positive pregnancies with a child affected by heart block was, however, significantly higher than in pregnancies resulting in babies without heart block (p<0.05).Seasonal timing of pregnancy influenced the outcome. Gestational susceptibility weeks 18-24 occurring during January-March correlated with a higher proportion of children with heart block and lower vitamin D levels during the same period in a representative sample of Swedish women and a corresponding higher proportion of children with heart block born in the summer (p<0.02). Maternal age or seasonal timing of pregnancy did not affect the outcome in Ro/La-negative pregnancies.

CONCLUSION

This study identifies maternal age and seasonal timing of pregnancy as novel risk factors for heart block development in children of Ro/La-positive women. These observations may be useful for counselling when pregnancy is considered.

Impact of pulse oximetry screening on the detection of duct dependent congenital heart disease: a Swedish prospective screening study in 39,821 newborns

OBJECTIVE

To evaluate the use of pulse oximetry to screen for early detection of life threatening congenital heart disease.

DESIGN

Prospective screening study with a new generation pulse oximeter before discharge from well baby nurseries in West Götaland. Cohort study comparing the detection rate of duct dependent circulation in West Götaland with that in other regions not using pulse oximetry screening. Deaths at home with undetected duct dependent circulation were included.

SETTING

All 5 maternity units in West Götaland and the supraregional referral centre for neonatal cardiac surgery.

PARTICIPANTS

39,821 screened babies born between 1 July 2004 and 31 March 2007. Total duct dependent circulation cohorts: West Götaland n=60, other referring regions n=100.

MAIN OUTCOME MEASURES

Sensitivity, specificity, positive and negative predictive values, and likelihood ratio for pulse oximetry screening and for neonatal physical examination alone.

RESULTS

In West Götaland 29 babies in well baby nurseries had duct dependent circulation undetected before neonatal discharge examination. In 13 cases, pulse oximetry showed oxygen saturations <or=90%, and (in accordance with protocol) clinical staff were immediately told of the results. Of the remaining 16 cases, physical examination alone detected 10 (63%). Combining physical examination with pulse oximetry screening had a sensitivity of 24/29 (82.8% (95% CI 64.2% to 95.2%)) and detected 100% of the babies with duct dependent lung circulation. Five cases were missed (all with aortic arch obstruction). False positive rate with pulse oximetry was substantially lower than that with physical examination alone (69/39 821 (0.17%) v 729/38 413 (1.90%), P<0.0001), and 31/69 of the "false positive" cases with pulse oximetry had other pathology. Thus, referral of all cases with positive oximetry results for echocardiography resulted in only 2.3 echocardiograms with normal cardiac findings for every true positive case of duct dependent circulation. In the cohort study, the risk of leaving hospital with undiagnosed duct dependent circulation was 28/100 (28%) in other referring regions versus 5/60 (8%) in West Götaland (P=0.0025, relative risk 3.36 (95% CI 1.37 to 8.24)). In the other referring regions 11/25 (44%) of babies with transposition of the great arteries left hospital undiagnosed versus 0/18 in West Götaland (P=0.0010), and severe acidosis at diagnosis was more common (33/100 (33%) v 7/60 (12%), P=0.0025, relative risk 2.8 (1.3 to 6.0)). Excluding premature babies and Norwood surgery, babies discharged without diagnosis had higher mortality than those diagnosed in hospital (4/27 (18%) v 1/110 (0.9%), P=0.0054). No baby died from undiagnosed duct dependent circulation in West Götaland versus five babies from the other referring regions.

CONCLUSION

Introducing pulse oximetry screening before discharge improved total detection rate of duct dependent circulation to 92%. Such screening seems cost neutral in the short term, but the probable prevention of neurological morbidity and reduced need for preoperative neonatal intensive care suggest that such screening will be cost effective long term.

Morphological and Physiological Predictors of Fetal Aortic Coarctation

Background— Prenatal diagnosis of aortic coarctation suffers from high false-negative rates at screening and poor specificity.

Methods and Results— This retrospective study tested the applicability of published aortic arch and ductal Z scores (measured just before the descending aorta in the 3-vessel and tracheal view) and their ratio on 200 consecutive normal controls at a median of 22±0 gestational weeks (range, 15±4 to 38±4 weeks). Second, this study tested the ability of serial Z scores to distinguish fetuses with coarctation within a cohort with ventricular and/or great arterial disproportion detected at screening or fetal echocardiography. Third, it evaluated the diagnostic significance of associated cardiac lesions, coarctation shelf, and isthmal flow disturbance. We studied 44 fetuses with suspected coarctation at 24±0 weeks (range, 17±3 to 37±4 weeks). Receiver-operating characteristic curves were created. Logistic regression tested the association between z scores, additional cardiac diagnoses, and coarctation. Good separation was found of isthmal Z scores for cases requiring surgery from controls and false-positive cases, and receiver-operating characteristic curves showed an excellent area under the curve for isthmal Z score (0.963) and isthmal-to-ductal ratio (0.969). Serial isthmal Z scores improved to >−2 in suspected cases with normal outcomes; those requiring surveillance or surgery remained <−2. Minor lesions did not increase the diagnostic specificity of coarctation, but isthmal flow disturbance increased the odds ratio of true coarctation versus arch hypoplasia 16-fold.

Conclusions— Isthmal Z scores and isthmal-to-ductal ratio are sensitive indicators of fetal coarctation. Serial measurements and abnormal isthmal flow patterns improve diagnostic specificity and may reduce false positives.

Z-scores of the fetal aortic isthmus and duct: an aid to assessing arch hypoplasia

OBJECTIVE

Prenatal diagnosis of isolated coarctation of the aorta suffers from high false positive and false negative rates. The aim of our study was to develop Z-scores for the aortic isthmus in normal fetuses as a reference for fetuses with suspected coarctation.

METHODS

The aortic isthmal diameter, immediately proximal to the insertion of the arterial duct, was measured prospectively in the transverse (three vessel and trachea) and sagittal views in 221 normal fetuses at 18 to 37 weeks' gestation. The ductal diameter was measured immediately before it entered the descending aorta in the same view. All measurements were repeated three times by a single investigator and averaged. A second investigator re-measured the images of 50 cases to assess interobserver variability. Z-scores were created relating isthmal and ductal diameters to femur length and gestational age. The ratio between the isthmal and ductal diameters was calculated.

RESULTS

The formula used to calculate Z-scores for the three diameters was: [ln(measured isthmal diameter) - (m ln(femur length or gestational age) + c)]/root MSE, where c is the intercept, m is a multiplier and MSE is the mean squared error. The ratio between isthmal and ductal diameters was close to a constant value of 1 (95% CI 0.97-1.01), regardless of the value of femur length or gestational age.

CONCLUSION

We have defined Z-scores for the fetal aortic isthmus and arterial duct measured in the three vessels and trachea view and for the isthmus in the sagittal plane. In suspected coarctation, these Z-scores and the isthmal to ductal ratio may help in longitudinal assessment of the aortic arch and aid in the prenatal diagnosis of coarctation.

Quality of life in children with hypoplastic left heart syndrome

AIM

To measure quality of life in children with hypoplastic left heart syndrome and their families.

METHODS

A questionnaire exploring socioeconomic status, structure and function of networks and psychological well-being was completed by the families of all 18 patients older than 2 years (age range 2.7-10.6). The results were compared with those of 180 healthy Swedish children matched for age and sex.

RESULTS

There were no significant differences between the groups in any of the aspects of socioeconomic status. Study group parents had not more available time for their child (p < 0.05) and more separations/divorces (p < 0.01). The patients had lower self-esteem (p < 0.05), more psychosomatic symptoms (p < 0.01) [corrected] and lower peer acceptance (p < 0.01) than control children.

CONCLUSION

With regard to psychological well-being, quality of life was significantly lower in children with hypoplastic left heart syndrome than in healthy controls.

Results of staged palliation for hypoplastic left heart syndrome: a complete population-based series

AIM

To study the outcome of staged palliation for classic hypoplastic left heart syndrome.

METHODS

Retrospective chart review. Risk factors for mortality were analysed using Cox's proportional hazard regression modelling.

RESULTS

From 1993 to 2004, 55 infants underwent Norwood stage I procedure at a median age of 8 d (range 1-19 d). Hospital survival was 39/55 (71%), and there were six late deaths (before stage II). Birthweight, circulatory arrest time and cardiopulmonary bypass time were independent risk factors for stage I hospital mortality (p=0.029, p=0.001 and p=0.003, respectively). Poor right ventricular function prior to stage I was a significant predictor for interstage mortality (p=0.02). Thirty-two patients underwent bidirectional cavopulmonary anastomosis, at a median age of 6.5 mo (range 2.0-9.5 mo), with seven late deaths. Two patients had a heart transplant after stage II. Total cavopulmonary connection (TCPC) was performed in 13 patients, at a median age of 33 mo (range 21-45 mo), without mortality. Kaplan-Meier survival was 58%, 52% and 45% at 6, 12 and 48 mo, respectively.

CONCLUSION

Low birthweight, long time on circulatory arrest and cardiopulmonary bypass were risk factors for stage I mortality. Poor right ventricular function was detrimental to intermediate outcome.

Failure to diagnose critical heart malformations in newborns before discharge--an increasing problem?

AIM

To determine what proportion of newborns with critical heart defects are discharged undiagnosed from the maternity ward.

METHODS

Data were retrieved retrospectively for infants born in our referral area from 1993 to 2001 and undergoing surgical or catheter-based intervention before 2 mo of age because of critical heart defects.

RESULTS

259 full-term infants had critical heart defects. Duct-dependent systemic circulation was present in 129, duct-dependent pulmonary circulation in 106, and 24 infants were not duct dependent but critically ill. In 51 infants (20%) the heart defect was not suspected before discharge from the maternity ward. Such late detection occurred more often in infants with duct-dependent systemic circulation (30%) and in children with defects that were not duct dependent (38%) than in children with duct-dependent pulmonary circulation (4%) (p<0.001). The proportion detected after discharge from the maternity ward increased from 13% in 1993-1995 and 21% in 1996-1998 to 26% in 1999-2001 (p<0.05).

CONCLUSION

Many infants with critical congenital heart defects are not diagnosed before discharge from the neonatal maternity ward. The proportion discharged undiagnosed has increased. Neonatal screening fails mainly in children with duct-dependent systemic circulation.

Perinatal management, counselling and outcome of fetuses with congenital heart disease

Prenatal treatment options for fetal heart disease are still limited but pharmacological treatment of fetal tachyarrhythmias is usually effective. Prenatal catheter interventions are likely to be an option in selected fetal cardiac defects in the future. Delivery should be at a tertiary care centre if the need for immediate neonatal transport is anticipated. When a cardiac problem is diagnosed in a fetus, the parents should be counselled by a paediatric cardiologist specialized in fetal cardiology in close co-operation with the obstetric team. The rate of termination is influenced by gestational age at diagnosis, the severity of the heart defect and the presence of associated malformations. In fetuses with isolated cardiac malformations who are in sinus rhythm with good myocardial function and no or trivial atrioventricular valve regurgitation, the risk of spontaneous intra-uterine death is low. Prenatal echocardiography has the potential to improve postnatal survival in infants with critical heart defects, especially those with duct-dependent systemic or pulmonary circulations.

Screening for duct-dependant congenital heart disease with pulse oximetry: a critical evaluation of strategies to maximize sensitivity

AIM

To evaluate the feasibility of detecting duct-dependent congenital heart disease before hospital discharge by using pulse oximetry.

DESIGN

Case-control study.

SETTING

A supra-regional referral centre for paediatric cardiac surgery in Sweden.

PATIENTS

200 normal term newborns with echocardiographically normal hearts (median age 1.0 d) and 66 infants with critical congenital heart disease (CCHD; median age 3 d).

METHODS

Pulse oximetry was performed in the right hand and one foot using a new-generation pulse oximeter (NGoxi) and a conventional-technology oximeter (CToxi).

RESULTS

With the NGoxi, normal newborns showed a median postductal saturation of 99% (range 94-100%); intra-observer variability showed a mean difference of 0% (SD 1.3%), and inter-observer variability was 0% (SD 1.5%). The CToxi recorded a significantly greater proportion of postductal values below 95% (41% vs 1%) in the normal newborns compared with NGoxi (p<0.0001). The CCHD group showed a median postductal saturation of 90% (45-99%) with the NGoxi. Analysis of distributions suggested a screening cut-off of <95%; however, this still gave 7/66 false-negative patients, all with aortic arch obstruction. Best sensitivity was obtained by adding one further criterion: saturation of <95% in both hand and foot or a difference of >+/-3% between hand and foot. These combined criteria gave a sensitivity of 98.5%, specificity of 96.0%, positive predictive value of 89.0% and negative predictive value of 99.5%.

CONCLUSION

Systematic screening for CCHD with high accuracy requires a new-generation oximeter, and comparison of saturation values from the right hand and one foot substantially improves the detection of CCHD.

[Limited value of prenatal risk group screening for heart abnormalities. Time for a general screening?]

544 fetuses at increased risk of cardiac malformations were examined by echocardiography from gestational week 14 to 40 (median 21), during the period January 1989-March 2002. A heart defect was diagnosed in 70 fetuses. Three false positive diagnoses and eight false negative diagnoses occurred (sensitivity 89 % and specificity 99 %). Seven were terminated (three with trisomy, two with concomitant diaphragmatic hernia and two with single ventricles) and eight died in utero. 22 of 52 liveborn infants died during the neonatal period. Fetal arrhythmia was diagnosed in 30 cases of which eight died prenatally. This risk group screening identified only 3.3 % of all infants with heart defects born during the study period. The ambition to diagnose a greater proportion prenatally would require a general screening program. In order to guarantee a high quality of specialized fetal cardiology service, referrals should be centralized to only a few units in the country.

Bubble contrast echocardiography in detecting pulmonary arteriovenous malformations after modified Fontan operations

The development of pulmonary arteriovenous malformations is a well-known complication after Fontan operations, and may result in significant morbidity due to increasing arterial desaturation. We compared the use of bubble contrast echocardiography and pulmonary angiography in detecting such malformations. We also examined which anatomical and haemodynamic variables were associated with their development. Our study includes 20 patients who had undergone modified Fontan procedures, 10 with atriopulmonary and 10 with total cavopulmonary connections, in Gothenburg between 1980 and 1991. All patients underwent cardiac catheterisation and pulmonary angiography. Bubble contrast echocardiography was performed at the same time, with injection of agitated polygelin colloid solution (Haemaccel, Hoechst) into the right and left pulmonary arteries, respectively. Transoesophageal echocardiography was used to detect the appearance of bubble contrast in the pulmonary venous atrium. The aim was also to evaluate the role of hepatic venous blood. Of the 20 patients, 9 (45%) had a positive contrast echocardiography study, compared with only 2 (10%) detected by pulmonary angiography. Patients with positive contrast echocardiography had a significantly lower arterial oxygen saturation than those with negative studies, both at rest (88% vs 95%, p < 0.01) and during exercise testing (78% vs 89%, p = 0.01). Bubble contrast echocardiography is much more sensitive in detecting pulmonary arteriovenous malformations than pulmonary angiography. By injecting echo contrast into the right and left pulmonary arteries, the method can be made highly selective. Pulmonary arteriovenous malformations develop much more frequently in patients with the Fontan circulation than previously reported.

Transient reduction of human left ventricular mass in carnitine depletion induced by antibiotics containing pivalic acid

OBJECTIVE

To study the effect of induced carnitine depletion on myocardial structure and function.

SUBJECTS AND DESIGN

7 healthy adult volunteers given 1200 mg pivmecillinam per day for 7-8 weeks were studied by echocardiography before and after 7-8 weeks of treatment and a 15 months follow up after the treatment period.

SETTING

Teaching hospital.

MAIN OUTCOME MEASURES

Carnitine concentration in serum, urine, and muscle and echocardiographic measurements.

RESULTS

After 7-8 weeks of treatment the median free serum carnitine concentration was reduced to 7% and the median total muscle carnitine concentration to 46% of the pretreatment levels. The median diastolic interventricular septum thickness decreased by 14% (mean 26%, P = 0.028) and the median left ventricular mass by 10% (mean 20%, P = 0.018). Fifteen months later these dimensions had increased but not completely returned to pretreatment values.

CONCLUSIONS

Extended treatment with pivalic acid containing antibiotics causes carnitine depletion which may lead to changes in cardiac structure.

Transventricular dilation for critical aortic stenosis in neonates

Critical aortic stenosis (CAOS) is not compatible with life when the ductus arteriosus closes. We have treated 11 consecutive cases with isolated CAOS. Symptom presentation was in the early neonatal period and diagnosis was made noninvasively at a mean age of 4 days. All were operated on with transventricular dilation (TVD) at a mean age of 4.7 days. There was no early mortality. There were two late deaths due to fibroelastosis. Both had the smallest aortic anulus diameter (5 mm). Two other patients had aortic root replacement, one at the age of 6.5 weeks due to intractable heart failure, and the other at the age of 3 months due to increasing gradient. In these two cases elective surgery was made possible by a successful TVD in the early neonatal period. TVD in this material was not associated with any early mortality, which makes this procedure a good alternative in the treatment of CAOS.

The influence of epidural blockade and pethidine administered during delivery on neonatal myocardial performance

The aim of the present study was to investigate whether obstetric analgesia with an epidural blockade (Marcaine, bupivacaine hydrochloride, 141.5 +/- 56.8 mg) and pethidine (95.0 +/- 30.7 mg) influenced neonatal myocardial function following vaginal delivery. Left ventricular output and other left ventricular function indices were measured 5.6 +/- 4.3 h postpartum with Doppler and M-mode echocardiography in a group of healthy, full-term, appropriate-for-gestational-age infants (n = 10) whose mothers had received both bupivacaine and pethidine during delivery, and in a similar group of newborn infants (n = 10) whose mothers had received only nitrous oxide/oxygen analgesia. In 7 of the 10 infants in each groups, a second assessment of myocardial function was performed 21.7 +/- 4.6 h post partum. There were no significant differences in any of the variables used to assess left ventricular function at either of the measurement points between the group of infants whose mothers had received bupivacaine/pethidine during delivery, and the group of infants whose mothers had received nitrous oxide/oxygen analgesia only.

Effect of subclavian flap angioplasty on growth and circulation of the left front leg in pigs

The effect of subclavian flap angioplasty on the growth of the left front limb and on its collateral circulation was studied in 11 pigs. The left subclavian artery and its first branch, the costocervical trunk, were divided while the remaining three branches--the deep cervical, the vertebral and the internal thoracic artery--were preserved. Postoperative angiographies (5 pigs) showed that the blood supply to the left front limb was maintained through these three branches, which acted as collaterals, supplying blood in retrograde fashion. The left vertebral artery was seen to be the predominant collateral already on postoperative day 1. Four months later the diameter of the left vertebral artery had increased more than that of the contralateral (right) vertebral artery. Eight months postoperatively the size of both front legs (6 pigs) was the same. No signs of cerebral disturbance were seen. The clinical implications of the findings are discussed.

Effects of left-to-right ductus shunting on left ventricular output and cerebral blood flow velocity in 3-day-old preterm infants with and without severe lung disease

The effects of early left-to-right ductus shunting on left ventricular output (LVO) and cerebral blood flow velocity (CBV) were investigated in 3-day-old preterm infants by means of two-dimensional Doppler and M-mode echocardiography. Nineteen infants required mechanical ventilation because of severe lung disease (group A), and 19 had mild or no lung disease (group B). Six infants in each group had predetermined Doppler and M-mode criteria of a hemodynamically significant left-to-right ductus shunt (hsPDA). In group A the LVO was similar in infants with and without hsPDA, but those with hsPDA had lower mean arterial pressure (p = 0.006) and lower mean systolic-diastolic CBV (p = 0.001) than those without hsPDA. In group B the presence of hsPDA was associated with a higher LVO (p = 0.002), whereas neither mean arterial pressure nor mean systolic-diastolic CBV differed significantly in infants with and without hsPDA. In infants without hsPDA, those in group A had higher LVO (p = 0.012), lower mean arterial pressure (p = 0.003), and lower estimated systemic vascular resistance (p = 0.004) than those in group B. These results indicate that severely ill preterm infants receiving mechanical ventilation are less able than spontaneously breathing infants to defend systemic pressures and cerebral perfusion through an increase of LVO when a large ductus shunt develops. Possible reasons include an elevated baseline LVO, caused by systemic vasodilation, and hence a low preload reserve.

Prevention of symptomatic patent ductus arteriosus with a single dose of indomethacin

To determine the efficacy of indomethacin to prevent the occurrence of symptomatic patent ductus arteriosus (PDA), a randomized clinical trial was conducted involving 32 preterm infants weighing 750 to 1500 g at birth who had hyaline membrane disease. By random assignment, 15 infants were given a single dose of indomethacin, 0.2 mg/kg intravenously, 24 hours after birth. Seventeen infants composed a control group for which indomethacin was reserved as treatment for symptomatic PDA. Birth weight, gestational age, male/female ratio, black/white ratio, and severity of disease were similar for both groups. Only one of the 14 survivors who received prophylactic indomethacin had symptomatic PDA, compared with nine of the 16 survivors in the control group (P = 0.007). There was no difference between the groups in development of bronchopulmonary dysplasia, duration of time endotracheal intubation, was required, duration in oxygen, duration to reach full feedings and regain birth weight, and duration of hospital stay. There was no difference between the two groups in incidence of intraventricular hemorrhage, and none developed necrotizing enterocolitis. These results indicate that the use of prophylactic indomethacin is beneficial in prevention of symptomatic PDA; the lack of differences in pulmonary sequelae or other complications may have been related to a population sample size not large enough to impart sufficient statistical power.

Prediction of symptomatic patent ductus arteriosus in preterm infants using Doppler and M-mode echocardiography

To investigate whether the development of symptomatic patent ductus arteriosus could be predicted, 26 preterm infants dependent on mechanical ventilation were examined daily with Doppler and M-mode echocardiography until 3 days after birth. The presence or absence of a hemodynamically significant ductus shunt, as judged from echocardiographic criteria, was tested for predictive power in terms of sensitivity, specificity and total error rate. Out of the 26 infants 13 developed symptomatic patent ductus arteriosus at a median age of 5 days (range 2-8). These 13 infants developed echocardiographic evidence of a large shunt at a median age of 2 days (range 1-3). The sensitivity of prediction was 18, 46 and 100% at 1, 2 and 3 days after birth. The specificity was 80, 92 and 85% and the total error rate was 52, 32 and 8%. Thus, accurate prediction was possible 3 days after birth.

Neonatal surgery for coarctation of the aorta. The Gothenburg experience

Thirty-four neonates (weights 0.97-4.47 kg) were operated on for coarctation of the aorta. They included five premature infants with birth weight less than or equal to 2.1 kg. All 34 were symptomatic, 31 severely so. Coarctation was "simple" in 12 cases and "complex" in 22; 12 with ventricular septal defect and 10 with more complex malformations. The mean age at operation was 11 days. Subclavian flap aortoplasty was used in 27 cases, a lusoric artery in two, and combined end-to-end anastomosis and flap repair in five. The main pulmonary artery was banded in 13 of the 22 complex coarctation syndromes. Absorbable suture was used in the last 22 cases. There was one early postoperative death. Serious ischaemic complications (bowel or limb gangrene) arose in four patients who were in severe heart failure preoperatively. During follow-up averaging 1.9 years there were two recurrences of coarctation. Resection with end-to-end anastomosis combined with subclavian flap aortoplasty when there is bulging ductal tissue or long, narrow isthmus and use of absorbable vascular suture may further lower the incidence of recurrent coarctation.

Doppler determination of cardiac output in infants and children: comparison with simultaneous thermodilution

Ten children, aged six weeks to 13 years, without intracardiac shunts or lesions that could cause turbulent flow in the ascending aorta or aortic regurgitation, underwent cardiac catheterization, including cardiac output measurements by thermodilution. Simultaneously with each of six consecutive thermodilution injections, mean and maximal blood velocities in the ascending aorta were measured by pulsed Doppler echocardiography from the suprasternal notch. Aortic root and aortic orifice diameters were measured with M-mode and cross-sectional echocardiography. One patient had to be excluded from the analysis because of inadequate Doppler recordings. The best agreement with the results of the thermodilution was observed when internal systolic aortic root diameter was combined with mean velocity (r = 0.97, y = 0.90x + 0.28, SEE = 0.31 liters/min). When cardiac output was normalized for body size, there was still a good correlation between the results of these two methods.

Effect of epidermal growth factor on lung liquid secretion in fetal sheep

Fetal lung liquid secretion depends on active transport of chloride ions. Chloride secretion in the stomach is inhibited by epidermal growth factor (EGF). For this reason, the effect of EGF on lung liquid secretion was measured using the impermeant-tracer technique in chronically-prepared fetal sheep. Infusion of EGF over 4 h resulted in decreased lung liquid secretion (from 4.2 +/- 0.6 to 1.7 +/- 0.8 ml/h, P = 0.02) and significant dose related tachycardia. During the infusion, plasma epinephrine levels increased from 27 +/- 5 to 67 +/- 13 pg/ml (P = 0.05) and norepinephrine levels increased from 257 +/- 31 to 544 +/- 69 pg/ml (P = 0.01). Since it is known that beta-adrenergic agonists inhibit lung liquid secretion, subsequent studies were performed with beta-adrenergic blockade using propranolol. Infusion of EGF and propranolol resulted in a significant decrease in lung liquid secretion (from 8.9 +/- 2.1 to 3.0 +/- 1.1 ml/h, P = 0.03). Infusion of propranolol alone had no demonstrable effect on lung liquid secretion. It is concluded that acute EGF infusion increases heart rate and stimulates catecholamine secretion in fetal sheep. EGF also inhibits lung liquid secretion, an effect which appears to be independent of a possible indirect catecholamine effect.

Single Doppler detection of left to right shunt through the ductus arteriosus

Forty-two infants and children were examined with unguided continuous and pulsed Doppler echocardiography before and/or after surgical closure of ductus arteriosus or in connection with cardiac catheterization. Presence or absence of diastolic reverse flow in the main pulmonary artery was evaluated for sensitivity and specificity to detect left to right ductus shunt. Diastolic reverse flow was detected in 15 of 16 patients with such a shunt and in 3 of 38 patients without a left to right ductus shunt. This corresponds to 94% sensitivity and 92% specificity. It is concluded that the accuracy of a single Doppler system in diagnosing patent ductus arteriosus is comparable to the results obtained with a Doppler interfaced to M-mode or cross-sectional echocardiography.

Estimation of stroke volume using Doppler echocardiography and left ventricular echocardiographic dimensions in infants and children

To evaluate the accuracy of noninvasive determination of stroke volume in infants and children, 28 patients (age range 4 weeks to 19 years) were studied. Stroke volume was calculated according to Teichholtz from M-mode echocardiographic tracings of left ventricular dimensions in 8 subjects. Agreement with thermodilution performed within 60 min of echocardiography was good (r = 0.995, y = 0.91x + 1.59, SEE = 1.8 ml). Since stroke volume correlated to body size we corrected for (height)3. After this correction there was still good agreement to thermodilution (r = 0.88, y = 1.29x-7.13, SEE = 7.1 ml/H3). M-mode echocardiography was then used as a reference method for evaluating two different Doppler methods in the remaining 20 subjects. Continuous wave Doppler stroke distance, calculated from the mean velocity, was combined with aortic root area (Method I), and stroke distance calculated from maximum velocity was combined with the aortic interleaflet area (Method II). Good agreement was found with Method I (r = 0.95, y = 1.01x-0.14, SEE = 8.1 ml) and Method II (r = 0.95, y = 1.04x-1.14, SEE = 8.4 ml). However, when stroke volume was normalized for (height)3, Method I was found to be superior to Method II.

Recurrence of symptomatic patent ductus arteriosus in extremely premature infants, treated with indomethacin

The administration of a single intravenous injection of indomethacin was followed by a major constrictive effect on the ductus in 36 of 42 very-low-birth-weight (less than or equal to 1000 gm) infants with symptomatic patent ductus arteriosus (PDA). In 26 of the 36 responders, the effect was sustained; symptomatic PDA recurred in the remaining 10. Infants who experienced a recurrence of symptomatic PDA had lower birth weights and had received indomethacin at an earlier postnatal age than did infants with a sustained effect. These results may be explained by differences in the production and clearance of prostaglandins or in the sensitivity of the ductus to prostaglandin effects between infants with a recurrence and infants with sustained constriction of PDA.