Cerebral blood flow dynamics during cardiac surgery in infants

BACKGROUND

In this pilot study, we investigated continuous cerebral blood flow velocity measurements to explore cerebrovascular hemodynamics in infants with congenital heart disease undergoing cardiac surgery.

METHODS

A non-invasive transfontanellar cerebral Doppler monitor (NeoDoppler) was used to monitor 15 infants (aged eight days to nine months) during cardiac surgery with cardiopulmonary bypass. Numerical and visual analyses were conducted to assess trends and events in Doppler measurements together with standard monitoring equipment. The mean flow index, calculated as the moving Pearson correlation between mean arterial pressure and time averaged velocity, was utilized to evaluate dynamic autoregulation. Two levels of impaired autoregulation were defined (Mean flow index >0.3/0.45), and percentage of time above these limits were calculated.

RESULTS

High quality recordings were achieved during 90.6% of the monitoring period. There was a significant reduction in time averaged velocity in all periods of cardiopulmonary bypass. All patients showed a high percentage of time with impaired dynamic autoregulation, with Mean flow index >0.3 and 0.45: 73.71% ± 9.06% and 65.16% ± 11.27% respectively. Additionally, the system promptly detected hemodynamic events.

CONCLUSION

Continuous transfontanellar cerebral Doppler monitoring could become an additional tool in enhancing cerebral monitoring in infants during cardiac surgery.

IMPACT

This pilot study demonstrates the feasibility of continuous transfontanellar Doppler monitoring of cerebral blood flow velocities during cardiac surgery in infants. It also demonstrates a high proportion of time with impaired cerebral autoregulation during cardiac surgery based on the Mean flow index. Continuous transfontanellar Doppler could become a useful tool to improve cerebral monitoring and provide new pathophysiological insight.

Detection of severe congenital heart defects in live-born infants in Norway 2017-2020

AIM

The aims of this nationwide retrospective cohort study were to determine the time and causes of detection of severe congenital heart defects (CHDs) in live-born infants in Norway between 2017 and 2020.

METHODS

Information regarding live-born infants with severe CHDs was retrieved from national registries and medical records.

RESULTS

A total of 219 776 infants were born in Norway from 01.01.2017 to 31.12.2020. Severe CHDs were diagnosed in 442 (0.2%) infants. Of these, 376 (85%) infants were diagnosed either prenatally (n = 203, 46%) or before discharge from hospital after birth (n = 173, 39%). A total of 56 (13%) infants were discharged with undetected CHDs. Time of detection was unknown in 10 cases (2%). The most frequent undetected CHDs at discharge were coarctation of the aorta/aortic arch hypoplasia (n = 24), atrioventricular septal defect (n = 13), anomalous pulmonary venous connection (n = 5) and coronary artery anomalies (n = 4). Seven (13%) children with undetected CHD experienced circulatory collapse out of hospital.

CONCLUSION

Most infants with severe CHDs in Norway were identified prior to hospital discharge. However, some infants were discharged undiagnosed. Awareness of undetected CHDs and immediate cardiac assessment in infants with signs of circulatory failure early in life are still important.

Factors Associated With Sinoatrial Reinnervation After Heart Transplantation

Background

Factors associated with sympathetic and parasympathetic sinoatrial reinnervation after heart transplantation (HTx) are inadequately studied.

Methods

Fifty transplant recipients were examined at 7 to 12 wk (index visit), 6, 12, 24, and 36 mo after HTx. Supine rest heart rate variability in the low-frequency (LF) domain (sympathetic and parasympathetic sinoatrial reinnervation) and the high-frequency (HF) domain (parasympathetic sinoatrial reinnervation) were measured repeatedly and related to selected recipient, donor, and perisurgical characteristics. We primarily aimed to identify index visit factors that affect the sinoatrial reinnervation process. Secondarily, we examined overall associations between indices of reinnervation and repeatedly measured recipient characteristics to generate new hypotheses regarding the consequences of reinnervation.

Results

LF and HF variability increased time dependently. In multivariate modeling, a pretransplant diagnosis of nonischemic cardiomyopathy (P = 0.038) and higher index visit handgrip strength (P = 0.028) predicted improved LF variability. Recipient age, early episodes of rejection, and duration of extracorporeal circulation were not associated with indices of reinnervation. Study average handgrip strength was positively associated with LF and HF variability (respectively, P = 0.005 and P = 0.029), whereas study average C-reactive protein was negatively associated (respectively, P = 0.015 and P = 0.008).

Conclusions

Indices of both sympathetic and parasympathetic sinoatrial reinnervation increased with time after HTx. A pretransplant diagnosis of nonischemic cardiomyopathy and higher index visit handgrip strength predicted higher indices of mainly sympathetic reinnervation, whereas age, rejection episodes, and duration of extracorporeal circulation had no association. HTx recipients with higher indices of reinnervation had higher average handgrip strength, suggesting a link between reinnervation and improved frailty. The more reinnervated participants had lower average C-reactive protein, suggesting an inhibitory effect of reinnervation on inflammation, possibly through enhanced function of the inflammatory reflex. These potential effects of reinnervation may affect long-term morbidity in HTx patients and should be scrutinized in future research.

Preoperative versus postoperative survival in patients with univentricular heart: a nationwide, retrospective study of patients born in 1990-2015

OBJECTIVES

Few data exist on mortality among patients with univentricular heart (UVH) before surgery. Our aim was to explore the results of intention to perform surgery by estimating preoperative vs postoperative survival in different UVH subgroups.

DESIGN

Retrospective.

SETTING

Tertiary centre for congenital cardiology and congenital heart surgery.

PARTICIPANTS

All 595 Norwegian children with UVH born alive from 1990 to 2015, followed until 31 December 2020.

RESULTS

One quarter (151/595; 25.4%) were not operated. Among these, only two survived, and 125/149 (83.9%) died within 1 month. Reasons for not operating were that surgery was not feasible in 31.1%, preoperative complications in 25.2%, general health issues in 23.2% and parental decision in 20.5%. In total, 327/595 (55.0%) died; 283/327 (86.5%) already died during the first 2 years of life. Preoperative survival varied widely among the UVH subgroups, ranging from 40/65 (61.5%) among patients with unbalanced atrioventricular septal defect to 39/42 (92.9%) among patients with double inlet left ventricle. Postoperative survival followed a similar pattern. Postoperative survival among patients with hypoplastic left heart syndrome (HLHS) improved significantly (5-year survival, 42.5% vs 75.3% among patients born in 1990-2002 vs 2003-2015; p<0.0001), but not among non-HLHS patients (65.7% vs 72.6%; p=0.22)-among whom several subgroups had a poor prognosis similar to HLHS. A total of 291/595 patients (48.9%) had Fontan surgery CONCLUSIONS: Surgery was refrained in one quarter of the patients, among whom almost all died shortly after birth. Long-term prognosis was largely determined during the first 2 years. There was a strong concordance between preoperative and postoperative survival. HLHS survival was improved, but non-HLHS survival did not change significantly. This study demonstrates the complications and outcomes encountering newborns with UVH at all major stages of preoperative and operative treatment.

Current outcomes of live-born children with double outlet right ventricle in Norway

OBJECTIVES

This population-based, comprehensive, retrospective study presented the clinical outcomes of all children born in Norway between 2003 and 2017 with double outlet right ventricle (DORV).

METHODS

All children born with DORV between 2003 and 2017 were identified in the Oslo University Hospital registry. Patients' characteristics, interventions, complications and deaths were recorded. Echocardiographic data were reviewed for classification according to current standards. We investigated time-dependent surgical reintervention and mortality using Kaplan-Meier analyses and determinants of treatment complications, reintervention and death using regression analyses.

RESULTS

Ninety-three children with DORV represented an annual median prevalence of 1.18 per 10 000 births in Norway. Six children received palliative care. With an intention to treat, a surgical route with the primary biventricular repair was followed for 62 children, staged biventricular repair for 15 and univentricular repair for 10 children. Major complications occurred in 1.0% and 6.2% of children following catheter or surgical intervention, respectively. No significant determinants of the complications were identified. Overall survival following treatment was 91.9%, 90.8%, 89.5% and 89.5% and corresponding freedom from surgical reintervention was 88.0%, 79.0%, 74.9% and 69.4% at 1, 2, 5 and 10 years, respectively. The presence of atrioventricular septal defect predicted an increased risk of mortality (hazard ratio: 7.16) but did not increase the risk of surgical reintervention.

CONCLUSIONS

In Norway, most children receive tailored treatment for DORV with low rates of complications, surgical reinterventions and mortality. However, atrioventricular septal defect remains a potential determinant of postoperative death.

Piggyback mounting for stent and valve deployment during percutaneous pulmonary valve implantation

OBJECTIVES

We report our experience in simultaneously implanting multiple stents and valves mounted on a single balloon before and during transcatheter pulmonary valve placement.

BACKGROUND

Heterogeneity and complexity of the right ventricular outflow tract (RVOT) may complicate stent deployment when preparing a landing zone for transcatheter pulmonary valve implantation.

METHODS

Retrospective analysis of patients from Children's Hospital of Colorado, USA; and Oslo University Hospital, Norway, undergoing transcatheter pulmonary valve replacement that had at least two stents mounted on a single balloon, deployed in the RVOT.

RESULTS

Over a 42-month period, a total of 50 subjects from the two centers met inclusion criteria for the study. Subjects were predominantly male (58%), and the median age was 17 years (4-78 years). In six subjects (12%), there was need for prestenting with use of the double or triple stent piggyback technique. Forty subjects (80%) had a Melody ™ TPV implanted. In 45 cases (90%), one or more stents were mounted over the pulmonary valve using its delivery system, either the Ensemble for the Melody™ TPV or the Edwards Commander for the SAPIEN 3 THV. Thirty-seven subjects (74%) had one stent mounted and eight subjects (16%) had two stents mounted over the pulmonary valve for simultaneous deployment. No complications related to this technique were reported.

CONCLUSIONS

The piggyback technique aims to simplify and facilitate adequate conduit preparation and valve insertion by minimizing manipulation across the outflow tract and decreasing the risk of stent distortion, misalignment, and embolization.

Detection of Cerebral High-Intensity Transient Signals by NeoDoppler during Cardiac Catheterization and Cardiac Surgery in Infants

There is a risk of gaseous and solid micro-embolus formation during transcatheter cardiac interventions and surgery in children with congenital heart disease (CHD). Our aim was to study the burden of high-intensity transient signals (HITS) during these procedures in infants. We used a novel color M-mode Doppler (CMD) technique by NeoDoppler, a non-invasive ultrasound system based on plane wave transmissions for transfontanellar continuous monitoring of cerebral blood flow in infants. The system displays CMD with 24 sample volumes and a Doppler spectrogram. Infants with CHD undergoing transcatheter interventions (n = 15) and surgery (n = 13) were included. HITS were manually detected based on an "embolic signature" in the CMD with corresponding intensity increase in the Doppler spectrogram. Embolus-to-blood ratio (EBR) defined HITS size. A total of 1169 HITS with a median EBR of 9.74 dB (interquartile range [IQR]: 5.10-15.80 dB) were detected. The median number of HITS in the surgery group was 45 (IQR: 11-150), while in the transcatheter group the median number was 12 (IQR: 7-24). During cardiac surgery, the highest number of HITS per hour was seen from initiation of cardiopulmonary bypass to aortic X-clamp. In this study we detected frequent HITS and determined the feasibility of using NeoDoppler monitoring for HITS detection.

Circulatory Response to Rapid Volume Expansion and Cardiorespiratory Fitness in Fontan Circulation

The role of dysfunction of the single ventricle in Fontan failure is incompletely understood. We aimed to evaluate hemodynamic responses to preload increase in Fontan circulation, to determine whether circulatory limitations in different locations identified by experimental preload increase are associated with cardiorespiratory fitness (CRF), and to assess the impact of left versus right ventricular morphology. In 38 consecutive patients (median age = 16.6 years, 16 females), heart catheterization was supplemented with a rapid 5-mL/kg body weight volume expansion. Central venous pressure (CVP), ventricular end-diastolic pressure (VEDP), and peak systolic pressure were averaged for 15‒30 s, 45‒120 s, and 4‒6 min (steady state), respectively. CRF was assessed by peak oxygen consumption (VO_2peak) and ventilatory threshold (VT). Median CVP increased from 13 mmHg at baseline to 14.5 mmHg (p < 0.001) at steady state. CVP increased by more than 20% in eight patients. Median VEDP increased from 10 mmHg at baseline to 11.5 mmHg (p < 0.001). Ten patients had elevated VEDP at steady state, and in 21, VEDP increased more than 20%. The transpulmonary pressure difference (CVP‒VEDP) and CVP were consistently higher in patients with right ventricular morphology across repeated measurements. CVP at any stage was associated with VO_2peak and VT. VEDP after volume expansion was associated with VT. Preload challenge demonstrates the limitations beyond baseline measurements. Elevation of both CVP and VEDP are associated with impaired CRF. Transpulmonary flow limitation was more pronounced in right ventricular morphology. Ventricular dysfunction may contribute to functional impairment after Fontan operation in young adulthood.ClinicalTrials.gov identifier NCT02378857.

Unexpected death in children with severe congenital heart defects in Norway 2004-2016

AIMS

Updated knowledge on the rates and causes of death among children with severe congenital heart defects (CHDs) is needed to further improve treatment and survival. This study investigated nationwide mortality rates in children with severe CHDs with an emphasis on unexpected mortality unrelated to cardiac intervention.

METHODS AND RESULTS

Data on all pregnancies and live-born children in Norway from 2004 to 2016 were obtained from national registries, the Oslo University Hospital's Clinical Registry for CHDs and medical records. Among 2359 live-born children with severe CHDs, 234 (10%) died before 2 years of age. Of these, 109 (46%) died in palliative care, 58 (25%) died of causes related to a cardiac intervention and 67 (29%) died unexpectedly and unrelated to a cardiac intervention, either before (n=26) or following (n=41) discharge after a cardiac intervention. Comorbidity (38/67, 57%), persistent low oxygen saturation (SaO₂; <95%; 41/67, 61%), staged surgery (21/41, 51%), residual cardiac defects (22/41, 54%) and infection (36/67, 54%) were frequent in children who died unexpectedly unrelated to an intervention. Two or more of these factors were present in 62 children (93%). The medical reports at hospital discharge lacked information on follow-up in many patients who died unexpectedly.

CONCLUSIONS

The numbers of unexpected deaths unrelated to cardiac intervention in children <2 years of age without comorbidity were low in Norway. However, close follow-up is recommended for infants with comorbidities, persistent low oxygen saturation, staged surgery or residual cardiac defects, particularly when an infection occurs.

Functional evidence of low-pressure cardiopulmonary baroreceptor reinnervation 1 year after heart transplantation

PURPOSE

Heart transplantation (HTx) implies denervation of afferent neural connections. Reinnervation of low-pressure cardiopulmonary baroreceptors might impact the development and treatment of hypertension, but little is known of its occurrence. The present prospective study investigated possible afferent reinnervation of low-pressure cardiopulmonary baroreceptors during the first year after heart transplantation.

METHODS

A total of 50 heart transplant recipients (HTxRs) were included and were evaluated 7-12 weeks after transplant surgery, with follow-up 6 and 12 months later. In addition, a reference group of 50 healthy control subjects was examined once. Continuous, non-invasive recordings of cardiovascular variables were carried out at supine rest, during 15 min of 20° head-up tilt, during Valsalva maneuver and during 1 min of 30% maximal voluntary handgrip. In addition, routine clinical data including invasive measurements were used in the analyses.

RESULTS

During the first year after HTx, the heart rate (HR) response to 20° head-up tilt partly normalized, a negative relationship between resting mean right atrial pressure and HR tilt response developed, low-frequency variability of the RR interval and systolic blood pressure at supine rest increased, and the total peripheral resistance response to Valsalva maneuver became stronger.

CONCLUSION

Functional assessments suggest that afferent reinnervation of low-pressure cardiopulmonary receptors occurs during the first year after heart transplantation, partially restoring reflex-mediated responses to altered cardiac filling.

Hepatic magnetic resonance T1-mapping and extracellular volume fraction compared to shear-wave elastography in pediatric Fontan-associated liver disease

BACKGROUND

Children with Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. Reliable noninvasive monitoring techniques are lacking or under development.

OBJECTIVE

To investigate surrogate indicators of hepatic fibrosis in adolescents with Fontan circulation by evaluating hepatic magnetic resonance (MR) T1 mapping and extracellular volume fraction measurements compared to US shear-wave elastography.

MATERIALS AND METHODS

We analyzed hepatic native T1 times and extracellular volume fractions with modified Look-Locker inversion recovery. Liver stiffness was analyzed with shear-wave elastography. We compared results between 45 pediatric patients ages 16.7±0.6 years with Fontan circulation and 15 healthy controls ages 19.2±1.2 years. Measurements were correlated to clinical and hemodynamic data from cardiac catheterization.

RESULTS

MR mapping was successful in 35/45 patients, revealing higher hepatic T1 times (774±44 ms) than in controls (632±52 ms; P<0.001) and higher extracellular volume fractions (47.4±5.0%) than in controls (34.6±3.8%; P<0.001). Liver stiffness was 1.91±0.13 m/s in patients vs. 1.20±0.10 m/s in controls (P<0.001). Native T1 times correlated with central venous pressures (r=0.5, P=0.007). Native T1 was not correlated with elastography in patients (r=0.2, P=0.1) or controls (r = -0.3, P=0.3). Extracellular volume fraction was correlated with elastography in patients (r=0.5, P=0.005) but not in controls (r=0.2, P=0.6).

CONCLUSION

Increased hepatic MR relaxometry and shear-wave elastography values in adolescents with Fontan circulation suggested the presence of hepatic fibrosis or congestion. Central venous pressure was related to T1 times. Changes were detected differently with MR relaxometry and elastography; thus, these techniques should not be used interchangeably in monitoring hepatic fibrosis.

The HARMONIC project: study design for the assessment of radiation doses and associated cancer risks following cardiac fluoroscopy in childhood

The HARMONIC project (Health Effects of Cardiac Fluoroscopy and Modern Radiotherapy in Paediatrics) is a European study aiming to improve our understanding of the long-term health risks from radiation exposures in childhood and early adulthood. Here, we present the study design for the cardiac fluoroscopy component of HARMONIC. A pooled cohort of approximately 100 000 patients who underwent cardiac fluoroscopy procedures in Belgium, France, Germany, Italy, Norway, Spain or the UK, while aged under 22 years, will be established from hospital records and/or insurance claims data. Doses to individual organs will be estimated from dose indicators recorded at the time of examination, using a lookup-table-based dosimetry system produced using Monte Carlo radiation transport simulations and anatomically realistic computational phantom models. Information on beam geometry and x-ray energy spectra will be obtained from a representative sample of radiation dose structured reports. Uncertainties in dose estimates will be modelled using 2D Monte Carlo methods. The cohort will be followed up using national registries and insurance records to determine vital status and cancer incidence. Information on organ transplantation (a major risk factor for cancer development in this patient group) and/or other conditions predisposing to cancer will be obtained from national or local registries and health insurance data, depending on country. The relationship between estimated radiation dose and cancer risk will be investigated using regression modelling. Results will improve information for patients and parents and aid clinicians in managing and implementing changes to reduce radiation risks without compromising medical benefits.

Severe congenital heart defects: incidence, causes and time trends of preoperative mortality in Norway

BACKGROUND AND AIMS

Severe congenital heart defects (CHDs) still represent one of the main causes of infant death. The risk factors associated with cardiac surgery and postoperative mortality are well known. We aimed to describe the rates, causes and time trends of mortality before surgery-including termination of pregnancies and palliative care-in fetuses and children below 2 years of age with severe CHDs.

METHODS AND RESULTS

Data concerning all 789 345 pregnancies in Norway from 2004 to 2016 were retrieved from the Medical Birth Registry of Norway, the Oslo University Hospital's Clinical Registry for Congenital Heart Defects, the Norwegian Cause of Death Registry, the National Registry, Statistics Norway, autopsy reports and medical records. When including termination of pregnancy and stillbirths, the number of fetuses and children with severe CHDs that did not reach the age of 2 years was 31%. Mortality among the 2359 live-born infants with severe CHDs was 10%, of whom 58% died before surgery. Of the preoperative deaths, 81% died in a palliative care setting, and comorbidity and univentricular CHDs were common among these infants. Together, palliative care and termination of pregnancy accounted for 86% of deaths in cases of severe CHDs, and this proportion increased during the study period (annual percent changes 1.3, 95% CI 0.4 to 2.1, p<0.001), mainly due to an increased termination rate.

CONCLUSIONS

Termination of pregnancy accounted for the majority of the deaths in fetuses and children with severe CHDs. Among live-born children, most preoperative deaths occurred in a palliative care setting and were strongly related to comorbidities and/or univentricular hearts.

Autonomic cardiovascular control changes in recent heart transplant recipients lead to physiological limitations in response to orthostatic challenge and isometric exercise

PURPOSE

Heart transplantation causes denervation of the donor heart, but the consequences for cardiovascular homeostasis remain to be fully understood. The present study investigated cardiovascular autonomic control at supine rest, during orthostatic challenge and during isometric exercise in heart transplant recipients (HTxR).

METHODS

A total of 50 HTxRs were investigated 7-12 weeks after transplant surgery and compared with 50 healthy control subjects. Continuous, noninvasive recordings of cardiovascular variables were carried out at supine rest, during 15 min of 60° head-up tilt and during 1 min of 30% of maximal voluntary handgrip. Plasma and urine catecholamines were assayed, and symptoms were charted.

RESULTS

At supine rest, heart rate, blood pressures and total peripheral resistance were higher, and stroke volume and end diastolic volume were lower in the HTxR group. During tilt, heart rate, blood pressures and total peripheral resistance increased less, and stroke volume and end diastolic volume decreased less. During handgrip, heart rate and cardiac output increased less, and stroke volume and end diastolic volume decreased less. Orthostatic symptoms were similar across the groups, but the HTxRs complained more of pale and cold hands.

CONCLUSION

HTxRs are characterized by elevated blood pressures and total peripheral resistance at supine rest as well as attenuated blood pressures and total peripheral resistance responses during orthostatic challenge, possibly caused by low-pressure cardiopulmonary baroreceptor denervation. In addition, HTxRs show attenuated cardiac output response during isometric exercise due to efferent sympathetic denervation. These physiological limitations might have negative functional consequences.

Survival in patients with univentricular hearts: the impact of right versus left ventricular morphology

Objective

Patients with univentricular hearts (UVH) have high mortality despite modern treatment, and better methods to identify patients at highest risk are needed. We wanted to improve risk stratification in patients with UVH by focusing on the prognostic significance of single right versus single left ventricular morphology (SRV vs SLV).

Methods

All 395 patients with UVH operated at our centre were prospectively included from 1972 to 2016 (195 SRV, 166 SLV, 34 mixed or indeterminate ventricular morphology). Diagnoses, UVH morphology, types of all operations and time and causes of death or heart transplantation (HTX) were recorded. The primary endpoint was death or HTX.

Results

Among the 111 non-Fontan patients, 88 died (SRV 62 vs SLV 20; p<0.0001), 32 due to heart failure (SRV 23 vs SLV 5; p=0.0012). Twenty-five  years of cumulative SRV versus SLV survival among the 284 Fontan patients (41 deaths/HTX) was 66.9% vs 87.9% (p=0.0027), partly explained by more deaths/HTX due to heart failure among patients with SRV (p=0.0006). Survival in patients with SRV with and without hypoplastic left heart syndrome (HLHS) was similar. SRV versus SLV was a strong predictor of death/HTX in multivariable proportional hazards analyses (RR 3.3, 95% CI 1.6 to 6.6).

Conclusion

SRV versus SLV is a strong short-term and long-term predictor of survival among patients with UVH, mainly explained by higher rates of death/HTX due to heart failure in the SRV group. Our findings apply to patients with SRV both with and without HLHS.

Endocarditis in children and adolescents with congenital heart defects: a Norwegian nationwide register-based cohort study

OBJECTIVES

Congenital heart defects (CHD) are the most common birth defects worldwide and are an important cause of morbidity and early death. A significant number of deaths occur among patients with infections. CHDs predispose to the development of infective endocarditis (IE) and represent a risk factor for increased mortality due to IE. The aim of this study was to investigate the occurrence and outcomes of IE in children and adolescents with CHDs.

METHODS

Data on all children with CHD and IE born in Norway between 1994 and 2016 were retrieved from the Oslo University Hospital's Clinical Registry for Congenital Heart Defects. Survivors were followed through 2016, and supplementary information was retrieved from medical records.

RESULTS

In this nationwide register-based cohort study, which included all 1 357 543 live births in Norway between 1994 and 2016, the incidence of IE according to the European Society of Cardiology diagnostic criteria was 2.2 per 10 000 person-years among children and adolescents with CHDs. The incidence was stable throughout the period. Most patients with IE had severe CHDs (75%) and had undergone open chest cardiac surgery or catheter-based cardiac interventions the last year before IE. IE-related mortality among children with CHDs and IE was 8% during the follow-up period (mean 12.4 years (±5.5 years)).

CONCLUSIONS

The incidence of IE among children and adolescents with CHDs was higher than the reported incidence in the general population. IE was associated with severe CHDs and recent complex cardiac interventions, and had significant mortality.

Psychosocial and clinical outcomes of percutaneous versus surgical pulmonary valve implantation

Objective

This prospective non-randomised study was performed to compare the psychosocial function and clinical outcomes following surgical and percutaneous implantation of a pulmonary valve at 3 months and 1 year after treatment.

Methods

All patients were consecutively admitted for treatment by either method from June 2011 to October 2014. The data of 20 patients treated with the percutaneous technique and 14 patients treated with open heart surgery were compared. Psychosocial function was measured by the Achenbach System of Empirically Based Assessment (ASEBA). We used linear mixed-effect models to investigate group changes between the psychosocial function and clinical data of 34 patients with congenital pulmonary valve disease.

Results

A significant difference in favour of the percutaneous pulmonary valve implantation group was observed regarding the ASEBA scores, specifically in the Thought problems subscale at 1 year (p=0.015), Attention problems subscale at 3 months (p=0.016) and 1 year (p=0.007) after treatment. After adjustment for the right ventricle to pulmonary artery pressure gradient at 3 months, a significant change in the Attention problems subscale (p=0.038) was noted in the percutaneous group. The New York Heart Association functional score significantly improved in both groups. The measured right ventricle to pulmonary artery pressure gradient was reduced significantly in both groups at 1 year.

Conclusions

Both methods led to significant clinical improvement. Thought and attention problems such as intrusive behaviour significantly decreased only in patients who underwent the percutaneous procedure. Complications as reintervention, bleeding and arrhythmia were only observed in the open surgery group.

Out-of-hospital sudden cardiac arrest in children with congenital heart defects

AIMS

Out-of-hospital sudden cardiac arrest (SCA) is a rare but devastating event in children and adolescents. The risk is assumed to be higher in children with congenital heart defects (CHDs) than in healthy individuals. The aim of the present study was to investigate the rate of and survival after out-of-hospital cardiac arrest in children 2-18 years old with CHDs.

METHODS AND RESULTS

Data concerning all live births in Norway between 1994 and 2009 were retrieved from the Medical Birth Registry of Norway, the patient administrative systems at all hospitals in Norway, the Oslo University Hospital's Clinical Registry for Congenital Heart Defects and the Norwegian Cause of Death Registry. Survivors were followed through 2012, and supplementary information for the deceased children was retrieved from medical records at Norwegian hospitals. Among the 943 871 live births in Norway from 1994 to 2009, 11 272 (1.2%) children had a CHD. We identified 11 (0.1%) children 2-18 years old with CHDs who experienced out-of-hospital SCA. The estimated rate of out-of-hospital SCA in children 2-18 years old with CHD was 10 per 100 000 person-years. Early cardiopulmonary resuscitation was initiated in all patients. Three children survived.

CONCLUSIONS

The incidence of and survival after out-of-hospital SCA in children with CHDs were comparable to the reported rates in the general child population.

In-hospital cost comparison between percutaneous pulmonary valve implantation and surgery

OBJECTIVES: Today, both surgical and percutaneous techniques are available for pulmonary valve implantation in patients with right ventricle outflow tract obstruction or insufficiency. In this controlled, non-randomized study the hospital costs per patient of the two treatment options were identified and compared.

METHODS: During the period of June 2011 until October 2014 cost data in 20 patients treated with the percutaneous technique and 14 patients treated with open surgery were consecutively included. Two methods for cost analysis were used, a retrospective average cost estimate (overhead costs) and a direct prospective detailed cost acquisition related to each individual patient (patient-specific costs).

RESULTS: The equipment cost, particularly the stents and valve itself was by far the main cost-driving factor in the percutaneous pulmonary valve group, representing 96% of the direct costs, whereas in the open surgery group the main costs derived from the postoperative care and particularly the stay in the intensive care department. The device-related cost in this group represented 13.5% of the direct costs. Length-of-stay-related costs in the percutaneous group were mean $3885 (1618) and mean $17 848 (5060) in the open surgery group. The difference in postoperative stay between the groups was statistically significant (P≤ 0.001).

CONCLUSIONS: Given the high postoperative cost in open surgery, the percutaneous procedure could be cost saving even with a device cost of more than five times the cost of the surgical device.

Mortality and complications in 3495 children with isolated ventricular septal defects

BACKGROUND

Ventricular septal defects (VSDs) are the most common congenital heart defects (CHDs). Previous studies indicate an increased risk of endocarditis, aortic regurgitation, left ventricular outflow tract obstructions, pulmonary hypertension, arrhythmias and sudden death in patients with isolated VSDs. The present nationwide cohort study reports mortality and cardiac complications requiring hospitalisation or intervention in children with isolated VSDs.

METHODS AND RESULTS

Medical information concerning all 943 871 live births in Norway in 1994-2009 was retrieved from the Medical Birth Registry of Norway, the Cardiovascular Disease in Norway project, the Oslo University Hospital's Clinical Registry of Congenital Heart Defects and the Norwegian Cause of Death Registry. Isolated VSDs were identified in 3495 children without known chromosomal aberrations or extracardiac malformations. Surgical or catheter-based treatment of VSD was performed in 181 (5.2%) cases. Twelve (0.3%) children with VSDs died before 2013. There was no operative mortality, and no excess mortality in children with isolated VSDs compared with children without VSDs (adjusted HR 0.8 (0.5 to 1.4), p=0.48). The following conditions were recorded as possible cardiac complications of the VSDs: endocarditis in 3 children (0.9‰), aortic regurgitation in 12 children (3.4‰), left ventricular outflow tract obstructions in no children (0.0‰), pulmonary hypertension in 1 child (0.3‰) and arrhythmias in 16 children (4.6‰).

CONCLUSIONS

The entire group of children with isolated VSDs had a favourable prognosis without excess mortality. Cardiac complications requiring hospitalisation or intervention, including endocarditis, aortic regurgitation, left ventricular outflow tract obstructions, pulmonary hypertension and arrhythmias, were infrequent during childhood.

TRIAL REGISTRATION NUMBER

NCT02026557.

Cerebral Microemboli Detection and Differentiation During Transcatheter Closure of Patent Ductus Arteriosus

The aim of this prospective study was to determine the frequency and composition of cerebral microemboli in a pediatric population, during transcatheter closure of patent ductus arteriosus (PDA). Multifrequency transcranial Doppler was used to monitor cerebral blood flow velocity (CBFV) and detect microembolic signals (MES) in the middle cerebral artery in 23 patients (median age 18 months). MES were automatically identified and differentiated according to composition; gaseous or solid. The procedure was divided into five periods: Arterial catheterization; venous catheterization; ductal catheterization; angiography; device placement and release. Timing of catheter manipulations and MES were registered and compared. MES were detected in all patients. The median number of signals was 7, (minimum 1, maximum 28). Over 95 % of all MES were gaseous. 11 % were detected during device placement while 64 % were detected during angiographic studies, significantly higher than during any other period (P < 0.001). There was a moderate correlation between the number of MES and volume of contrast used, (R = 0.622, P < 0.01). There was no correlation with fluoroscopic time or duration of procedure. This is the first study to investigate the timing and composition of cerebral microemboli during PDA occlusion. Microemboli were related to specific catheter manipulations and correlated with the amount of contrast used.

Sudden unexpected death in children with congenital heart defects

AIMS

Congenital heart defects (CHDs) are the most common birth defects and are an important cause of death in children. The fear of sudden unexpected death has led to restrictions of physical activity and competitive sports. The aim of the present study was to investigate the rate of sudden unexpected deaths unrelated to surgery in children 2-18 years old with CHDs and, secondarily, to determine whether these deaths were related to cardiac disease, comorbidity, or physical activity.

METHODS AND RESULTS

To identify children with CHDs and to determine the number of deaths, data concerning all 9 43 871 live births in Norway in 1994-2009 were retrieved from the Medical Birth Registry of Norway, the Cardiovascular Disease in Norway project, the Oslo University Hospital's Clinical Registry for Congenital Heart Defects and the Norwegian Cause of Death Registry. Survivors were followed through 2012, and information for the deceased children was retrieved from medical records at Norwegian hospitals. Among 11 272 children with CHDs, we identified 19 (0.2%) children 2-18 years old who experienced sudden unexpected deaths unrelated to cardiac surgery. A cardiac cause of death was identified in seven of these cases. None of the children died during physical activity, whereas two children survived cardiac arrest during sports.

CONCLUSION

Sudden unexpected death was infrequent among children with CHDs who survived 2 years of age. Comorbidity was common among the children who died. This study indicates that sudden unexpected death in children with CHDs rarely occurs during physical activity.

Pulmonary Valve Replacement With a Bovine Pericardial Valve

Objectives:

From a population of 90 patients after pulmonary valve replacement with a biological valve (Carpentier-Edwards Perimount valve), 56 of 80 available patients were examined five years after surgery.

Background:

Pulmonary valve replacement is needed in many patients with congenital heart disease. Homografts have limited availability and predictable degeneration, and mechanical valves require anticoagulation. No superiority of one kind of pulmonary valve replacement has been shown. Biological valves that are readily available are being used and evaluated in increasing numbers.

Methods:

In this cross-sectional study, five years following surgery, data were gathered from hospital charts, echocardiography, stress echocardiography, magnetic resonance imaging, and exercise testing.

Results:

In 90 patients, there were three new valve replacements, one early cardiac death, and four late noncardiac deaths. Echocardiographic assessment of the study group showed pulmonary Doppler velocities (m/s) before, after operation, and at five-year follow-up of 2.8 ± 1.1, 1.6 ± 0.4, and 2.3 ± 0.7, respectively. The assessed insufficiencies (0-3) at the same times were 2.3 ± 1.0, 0.3 ± 0.4, and 1.1 ± 0.8. Maximal oxygen uptake increased from 65.6% ± 10.1% to 77.1% ± 18.2% of predicted and QRS width increased by 7 ± 23ms. Valve degeneration could be associated with young age but not with diagnosis or valve size.

Conclusion:

In our study, the biological valve in the pulmonary position showed excellent mid-term results with few reoperations, low gradients, and mild to moderate insufficiency. Oversizing, in contrast to young age, was not a risk factor for valve degeneration. In younger patients, this allows later percutaneous replacement, reducing the need for further surgery. However, longer follow-up is needed.

Perceived health after percutaneous pulmonary valve implantation: in-depth interviews of patients and next-of-kin

OBJECTIVE

Percutaneous pulmonary valve implantation is an alternative to open heart surgery in selected patients with pulmonary outflow tract disorder. The technique may reduce the number of open-chest surgeries in these patients. This study was conducted to understand how the patients and their next-of-kin experienced this new treatment option.

DESIGN

Qualitative explorative design with individual in-depth interviews.

SETTING

Oslo University Hospital, the only cardiac centre in Norway offering advanced surgical and interventional treatment to patient with congenital heart defects, serving the whole Norwegian population.

PARTICIPANTS

During a 2-year period a total of 10 patients, median age 17 (7-30) and 18 next-of-kin were consecutively selected for individual in-depth interviews 3-6 months after the pulmonary valve implantation. The verbatim transcripts were analysed using a phenomenological methodology.

RESULTS

Patients emphasised the importance of regaining independence and taking control of daily life shortly after the new interventional treatment. Renewed hope towards treatment options was described as 'a light in the tunnel'. Next-of-kin emphasised the importance both for the patient and their family of resuming normal life quickly after the procedure. The physical burden was experienced as minor after the minimally invasive intervention, compared to their previous experience with surgical procedures.

MAIN OUTCOME MEASURE

The importance of maintaining normality in everyday life for a good family function.

CONCLUSIONS

The repeated surgeries during infancy and adolescence of patients with congenital heart disease represent a heavy burden both for the patient and their family. All families especially emphasised the importance of resuming normal life quickly after each procedure. The novel technique of pulmonary valve implantation is thus a favourable approach because of minor interference in daily life.

Hyperoxic resuscitation after hypoxia-ischemia induces cerebral inflammation that is attenuated by tempol in a reporter mouse model with very young mice

BACKGROUND

Oxygen supplementation is still part of international resuscitation protocols for premature children. Mechanisms for tissue damage by hypoxia/ischemia in the extreme premature involve inflammation.

AIM AND METHOD

To study cerebral inflammation after hypoxia/ischemia and oxygen treatment in the premature, we measured NF-κB activity in 5-day-old transgenic reporter mice in response to experimental hypoxia/ischemia. results were correlated to cerebral histological evaluation and plasma cytokine levels. A treatment strategy with the antioxidant tempol was tested.

RESULTS

One day after hypoxia/ischemia NF-κB activation was increased compared to controls [mean difference: 10.6±4.6% (P=0.03)]. Exposure to 100% oxygen after hypoxia/ischemia further increased NF-κB activation compared to hypoxia/ischemia alone [mean difference: 15.0±5.5% (P=0.01)]. Histological changes in the brain were positively correlated with NF-κB activity (P<0.001), but we found no significant difference in tissue damage between resuscitation with air and resuscitation with pure oxygen. Administration of tempol reduced NF-κB activation [mean difference: 14.6±5.0% (P=0.01)] and the plasma level of cytokines; however, the histological damage score was not affected.

CONCLUSION

Cerebral inflammatory response after hypoxia/ischemia in a mouse model with immature brain development corresponding to human prematurity prior to 32 weeks' gestation was influenced by administration of oxygen. Tempol treatment attenuated inflammation but did not reduce the extent of histological cerebral damage.

NF-κB activity in perinatal brain during infectious and hypoxic-ischemic insults revealed by a reporter mouse

Infants suffering from infection or hypoxia-ischemia around the time of birth can develop brain damage resulting in life-long impairment such as cerebral palsy, epilepsy and cognitive disability. Inflammation appears to be an important contributor irrespective of whether the primary event is infection or hypoxia-ischemia. Activation of the transcription factor NF-κB is a hallmark of inflammation. To study perinatal brain inflammation, we developed a transgenic reporter mouse for imaging NF-κB activity in live animals and tissue samples. The reporter genes firefly luciferase and a destabilized version of enhanced GFP (dEGFP) were regulated by common NF-κB sites using a bidirectional promoter. Luciferase activity was imaged in vivo, while dEGFP was detected at cellular level in tissue sections. In newborn mice subjected to experimental models of infections or hypoxia-ischemia; luciferase signal increased in brains of live animals. In brain sections dEGFP expression, revealing NF-κB activation was observed in the endothelial cells of the blood-brain barrier in all disease models. In meningitis and hypoxia-ischemia expression of dEGFP was also induced in perivascular astrocytes. In conclusion, by using this transgenic reporter mouse in experimental models of perinatal complications, we could assess NF-κB activity in vivo and subsequently determine the cellular origin in the tissues.

[Percutaneous catheter-based implantation of artificial pulmonary valves in patients with congenital heart defects]

BACKGROUND

Percutaneous catheter-based implantation of artificial heart valves is a new technique that may supplement surgery and which may be used more in the future. We here report our first experience with implantation of artificial pulmonary valves in children with congenital heart defects.

MATERIAL AND METHODS

Eligible patients were those with symptoms of heart failure combined with stenosis and/or insufficiency in an established artificial right ventricular outflow tract. The valve was inserted through a catheter from a vein in the groin or neck. Symptoms, echocardiography, invasive measurements and angiography were assessed for evaluation of treatment effect. Our treatment results are reported for the period April 2007-September 2009.

RESULTS

Ten patients (seven men and three women, median age 17 years) were assessed. The procedure reduced pressure in the right ventricle (p = 0.008) and resolved the pulmonary insufficiency in all patients. The median time in hospital was two days. No patients had complications that were directly associated with the implantation procedure. One patient developed a pseudoaneurysm in the femoral artery, another had a short-lasting fever two days after the procedure and one patient experienced a stent fracture that required surgery 9 months after the implantation. After 6 months all patients had a reduced pressure gradient in the right ventricular outflow tract (p = 0.008), the pulmonary insufficiency had improved (p = 0.006) and they all reported improval of symptoms. These results persisted for at least 24 months for the four patients who were monitored until then.

INTERPRETATION

Percutaneous catheter-based implantation of artificial pulmonary valves improves hemodynamics in the right ventricle of selected patients with congenital heart defects. A randomized controlled study should be undertaken to provide a stronger evidence-base for usefulness of this procedure.

Reoxygenation of hypoxic mice with 100% oxygen induces brain nuclear factor-kappa B

Oxidative stress is closely related to inflammation, a pathologic process characterized by activation of the transcriptional factor nuclear factor-kappa B (NF-kappaB). We have used transgenic NF-kappaB luciferase reporter mice to assess brain NF-kappaB activity noninvasively in living mice. We have studied NF-kappaB activation in hypoxic mice reoxygenated with either 21% O2 (room air) or 100% O2. Forty-one mice exposed for 2 h to 4% oxygen and then randomized to reoxygenation with pure oxygen or room air were investigated. A control mouse was dedicated to every mouse exposed to hypoxia. In vivo luminescence originated from brain was measured from mice 2 d before hypoxia, and 3 h after reoxygenation. A change in luminescence between the mouse exposed to hypoxia and its control demonstrates an alteration in NF-kappaB activity. Because of high mortality among males, only females were included. Six female mice died. Nineteen female mice were reoxygenated with room air, 16 with pure oxygen. We observed a significantly higher luminescence in the brain of the 100% O2 group versus the 21% O2 group. Our data indicate that brain NF-kappaB activity is increased in mice subjected to 4% oxygen followed by reoxygenation with 100% oxygen. However, when reoxygenation occurs with 21% O2 (room air), no elevation in NF-kappaB activity is observed. Thus, reoxygenation with room air may induce less brain inflammation than reoxygenation with pure oxygen.

[Clinical risk index for small premature infants]

BACKGROUND

The clinical risk index for babies (CRIB) is a score given to extremely small prematures as a tool for expressing initial sickness. It was developed in order to compare results among different neonatal intensive care units (NICUs).

MATERIAL AND METHODS

The CRIB score was determined for prematures with birth weight < or = 1,000 g born at the Central Hospital in Akershus during the 1995-99 period. The results are measured as the survival rate until discharge.

RESULTS

45 babies where treated at our NICU during this five-year period. Median gestation age was 27 weeks (range: 23-32 weeks), median birth weight was 875 g (range: 475-1,000 g), median CRIB was 4 (range: 1-16). The survival rate until discharge was 89%. To validate the CRIB score as a predictor for hospital mortality, a receiver-operating curve (ROC) was constructed. The area under the ROC curve was 0.93.

INTERPRETATION

CRIB proved to be a good predictor for hospital mortality and seems a useful indicator for initial sickness.

The use of CRIB (clinical risk index for babies) score in auditing the performance of one neonatal intensive care unit

The CRIB (clinical risk index of babies) score was developed to overcome the disadvantages of birthweight-specific comparisons between neonatal units. The aims of this study were to assess the ability of CRIB score compared to birthweight and gestational age to predict hospital mortality in very low birthweight infants and to use CRIB score in auditing one unit's performance during a prolonged time period. The charts of 335 infants with birthweight < or = 1500 g born between 1980 and 1995 were reviewed retrospectively. CRIB predicted hospital mortality significantly better than birthweight and gestation and performed equally well, whether the infants were treated with synthetic surfactant or not. When adjusting for CRIB score there was a significant improvement in the unit's performance, probably owing to the introduction of surfactant. As small samples tend to be associated with wide confidence intervals, use of CRIB is recommended in comparing risk adjusted mortality in a single unit over several years, as in this study, or between large groups of neonatal units over shorter periods.