Cardiac troponin I, cardiac troponin-specific autoantibodies and natriuretic peptides in children with hypoplastic left heart syndrome

Quantification of ventricular stress in univentricular hearts during early childhood using age-independent zlog-NT-proBNP

BACKGROUND

Children with univentricular hearts (UVH) undergo up to three palliative surgical procedures to achieve complete circulatory separation (Fontan circulation). As a marker of cardiac wall stress, NT-proBNP is a promising tool to assess systemic ventricular load in these patients. However, different reference intervals (RI) apply to each stage, as NT-proBNP is highly age-dependent.

METHODS

Children undergoing systemic-to-pulmonary (SP) shunt placement (stage 1), bidirectional cavopulmonary shunt (BCPS, stage 2) or total cavopulmonary connection (TCPC, stage 3) between 2011 and 2021 with NT-proBNP measurement within 7 days before surgery were included. Furthermore, outpatients after TCPC with NT-proBNP measurement were enrolled. Biomarker levels were evaluated using its age-adjusted z-score ("zlog-NT-proBNP"; age-independent RI, -1.96 to +1.96), allowing comparison between different stages and revealing changes in systemic ventricular load independent of the marked physiological decline in RI with age.

RESULTS

Overall, 289 children (227 before, 62 after TCPC) met the eligibility criteria. Median time between blood sampling and surgery (SP shunt/BCPS/TCPC) was 2 [1-3] days and 3.2 [2.0-4.5] years after TCPC. Age-adjusted zlog-NT-proBNP levels were 3.47 [2.79-3.93] in children with native UVH (before SP shunt), 3.10 [1.89-3.58] at stage 1 (before BCPS), 1.08 [0.51-1.88] at stage 2 (before TCPC), and 1.09 [0.72-1.75] at stage 3 (after TCPC/Fontan completion). Consequently, BCPS revealed the strongest decrease (median - 2.02 logarithmized standard deviations, p < 0.001).

CONCLUSIONS

In children with UVH undergoing staged Fontan palliation, zlog-NT-proBNP is a highly promising tool for course assessment of systemic ventricular load, independent of the age-related decline in physiological NT-proBNP concentration.

Current state of the art in hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a complex congenital heart condition in which a neonate is born with an underdeveloped left ventricle and associated structures. Without palliative interventions, HLHS is fatal. Treatment typically includes medical management at the time of birth to maintain patency of the ductus arteriosus, followed by three palliative procedures: most commonly the Norwood procedure, bidirectional cavopulmonary shunt, and Fontan procedures. With recent advances in surgical management of HLHS patients, high survival rates are now obtained at tertiary treatment centers, though adverse neurodevelopmental outcomes remain a clinical challenge. While surgical management remains the standard of care for HLHS patients, innovative treatment strategies continue to be developing. Important for the development of new strategies for HLHS patients is an understanding of the genetic basis of this condition. Another investigational strategy being developed for HLHS patients is the injection of stem cells within the myocardium of the right ventricle. Recent innovations in tissue engineering and regenerative medicine promise to provide important tools to both understand the underlying basis of HLHS as well as provide new therapeutic strategies. In this review article, we provide an overview of HLHS, starting with a historical description and progressing through a discussion of the genetics, surgical management, post-surgical outcomes, stem cell therapy, hemodynamics and tissue engineering approaches.

High-sensitivity cardiac troponins in pediatric population

Apparently healthy children often complain of chest pain, especially after physical exercise. Cardiac biomarker levels are often measured, but the clinical relevance of these assays in children is still debated, even when a cardiac disease is present. Coronary artery disease is exceedingly rare in children, but elevated circulating levels of cardiac troponin I (cTnI) and T (cTnT) in an acute setting may help detect heart failure due to an unknown cardiac disorder, or worsening heart failure, particularly in combination with other biomarkers such as B-type natriuretic peptides. However, the interpretation of biomarkers is often challenging, especially when institutions transition from conventional cTn assays to high-sensitivity (hs-cTn) methods, as well demonstrated in the emergency setting for adult patients. From a clinical perspective, the lack of established reference values in the pediatric age is the main problem limiting the use of hs-cTn methods for the diagnosis and managements of cardiac diseases in infants, children and adolescents. This review aims to discuss the possibility to use hs-cTnI and hs-cTnT to detect cardiac disease and to explore age-related differences in biomarker levels in the pediatric age. We start from some analytical and pathophysiological considerations related to hs-cTn assays. Then, after a systematic literature search, we discuss the current evidence and possible limitations of hs-cTn assay as indicators of cardiac disease in the most frequently cardiac disease in pediatric setting.

Role of cardiac magnetic resonance strain analysis in patients with hypoplastic left heart syndrome in evaluating right ventricular (dys)function: a systematic review

OBJECTIVES

Right ventricular dysfunction predicts death in patients with hypoplastic left heart syndrome (HLHS), but differences in morphology and loading conditions make calculation of the ejection fraction (EF), a challenging measure of its function. Our goal was to evaluate how strain measurements with cardiac magnetic resonance feature tracking could be used to evaluate right ventricular function in patients with HLHS.

METHODS

A systematic search of the literature was performed by 2 independent researchers using the terms 'population', 'intervention', 'comparison', 'outcome' and 'time criteria'. PubMed and the Ovid database were searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Our review included 8 studies with 608 participants with ventricular strain values obtained using cardiac magnetic resonance feature tracking. After stage I palliation, global strain was reduced in patients after a hybrid procedure and a right ventricle-to-pulmonary artery conduit compared with a modified Blalock-Taussig shunt despite similar EFs. Global longitudinal strain did not differ between stage II and stage III (Fontan) palliation. Fontan patients had significantly impaired global longitudinal and circumferential strain compared to the left ventricular strain of the controls. Studies of Fontan patients that included patients with HLHS who were part of a cohort with a single right ventricle showed impaired global circumferential strain compared with the cohort with a single left ventricle, with controls, and over time. In this group, impaired global circumferential strain was associated with major adverse cardiac events.

CONCLUSIONS

Cardiac magnetic resonance feature tracking can be used in patients with HLHS to evaluate RV strain and demonstrate differences between surgical strategies, over time and compared with controls. It could be used alongside clinical symptoms and EF values to detect ventricular dysfunction.

Prognostic value of non-acute high sensitive troponin-T for cardiovascular morbidity and mortality in adults with congenital heart disease: A systematic review

BACKGROUND

Elevation of high-sensitivity troponin-T (hs-TnT) is linked to cardiovascular morbidity and mortality. However, its prognostic value for survival and cardiovascular events and its relation to clinical characteristics and cardiac function parameters in clinically asymptomatic adults with congenital heart disease (ACHD) needs further exploration.

METHODS

A systematic literature search was performed in PubMed and Cochrane from 2010 to May 2020 for hs-TnT as a prognostic marker in ACHD. Three independent reviewers evaluated the articles according to the Study Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies of the National Heart, Lung, and Blood Institute. Overall, eight studies with a total of 2162 ACHD patients (18-63 years) were included.

RESULTS

Hs-TnT level was elevated in 8-26% of asymptomatic ACHD. The follow-up for all-cause mortality and cardiovascular events ranged from 3.0 to 5.6 years and in 8-38% of the participants cardiac endpoints were reached. Throughout the included studies, elevated hs-TnT was found to be an independent predictor for survival and heart failure in stable ACHD. Serial hs-TnT measurement was found to be beneficial over single measurement. Hs-TnT levels were correlated with male sex, higher age, and higher New York Heart Association class and associated with several cardiac dysfunction parameters.

CONCLUSION

More scientific research investigating the prognostic value of hs-TnT in stable ACHD is needed and the clinical relevance to guide aftercare has still to be determined.

MicroRNAs as potential biomarkers in congenital heart surgery

OBJECTIVE

Pediatric congenital heart surgery (CHS) involves intracardiac, valvular, and vascular repairs. Accurate tools to aid short-term outcome prediction in pediatric CHS are lacking. Clinical scores, such as the vasoactive-inotrope score and ventilation index, are used to define outcome in clinical studies. MicroRNA-1-3p (miR-1) is expressed by both cardiomyocytes and vascular cells and is regulated by hypoxia. In adult patients, miR-1 increases in the circulation after open-heart cardiac surgery, suggesting its potential as a clinical biomarker. Thus, we investigated whether perioperative circulating miR-1 measurements can help predict post-CHS short-term outcomes in pediatric patients.

METHODS

Plasma miR-1 was retrospectively measured in a cohort of 199 consecutive pediatric CHS patients (median age 1.2 years). Samples were taken before surgery and at the end of the operation. Plasma miR-1 concentration was measured by reverse transcription-quantitative polymerase chain reaction and expressed as miR-1 copies/μL and as relative expression to spiked-in exogenous cel-miR-39.

RESULTS

Baseline plasma miR-1 did not vary across different diagnoses, increased during surgery (204-fold median relative increase, P < .001), and was associated with aortic crossclamp duration postoperatively (P < .001). Importantly, miR-1 levels at the end of the operation positively correlated with intensive care stay (P < .001), early severe cardiovascular events (P = .01), and with high vasoactive-inotrope score (P = .001) and ventilation index (P < .001), suggesting that miR-1 could accelerate the identification of patients with cardiopulmonary bypass-related ischemic complications, requiring more intensive support.

CONCLUSIONS

Our study suggests miR-1 as a novel potential circulating biomarker to predict early postoperative outcome and inform clinical management in pediatric heart surgery.

What is the Significance of Elevated Troponin I in Children and Adolescents? A Diagnostic Approach

Troponin is a marker that displays cardiac injury quickly and accurately. In adults, troponin elevation is usually associated with coronary artery disease and requires urgent cardiac catheterization. In healthy children, myocardial injury is rare and may develop due to many different causes. Therefore, troponin elevation in children and adolescents does not usually require emergency cardiac catheterization. The aim of this study is to assess the most common causes of troponin elevation in children and adolescents and to show which diagnostic tests are helpful in assessing pediatric patients with elevated troponin. Patients who had been diagnosed with troponin I elevation (> 0.06 ng/ml) at Dr. Sami Ulus Maternity, Children's Health and Disease Training and Research Hospital between 2007 and 2018 were retrospectively evaluated. Patients undergoing cardiac surgery and those with severe congenital heart disease were excluded from the study. The medical records of the patients were examined and age, gender, diagnostic tests, and diagnosis were evaluated. During the study period, the records of 972 patients were obtained. 213 patients were excluded from the study because of heart surgery, congenital heart disease, and neonatal asphyxia or sepsis. Of the remaining 759 patients, 58% were male, 42% were female, and the median age was 4 years (3 days to 17 years). The most frequent causes are myopericarditis (n: 164), drug intoxications (n: 85), carbon monoxide poisoning (n: 74), perimyocarditis (n: 65), and intensive inhalation β agonist use in acute asthma and lower respiratory tract infections (n: 70). Patients diagnosed with myocarditis and myopericarditis were admitted with a complaint of chest pain, and the diagnosis was made by history, physical examination, ECG, and echocardiographic findings. Unlike adults, troponin I elevation may be associated with many cardiac and non-cardiac pathologies in children. The most common pathologies in cardiac etiology are myopericarditis and perimyocarditis and can be diagnosed by history, physical examination, ECG, and echocardiography. Cardiac catheterization is not necessary except for rare cardiac pathologies and does not alter the prognosis.

Risk factor analysis for a complicated postoperative course after neonatal arterial switch operation: The role of troponin T

OBJECTIVE

To find risk factors for a complicated early postoperative course after arterial switch operation (ASO) in neonates with d-transposition of the great arteries (dTGA). In addition to anatomical and surgical parameters, the predictive value of early postoperative troponin T (TnT) values in correlation to the early postoperative course after ASO is analyzed.

METHODS

Seventy-nine neonates (57 (72%) male) with simple dTGA treated by ASO between 2009 and 2016 were included in the analysis. A complicated early postoperative course (30 days) was defined by one of the following criteria: (A) moderate to severe cardiac dysfunction without rhythm disturbances, (B) rhythm disturbances causing hemodynamic instability with the need for medical treatment, (C) signs for ischemia in ECG, (D) need for surgical or catheter interventional reinterventions other than diagnostic, or (E) other reasons.

RESULTS

Forty of 79 patients (51%) showed a complicated early postoperative course after ASO, with 2 patients dying after 13 and 16 days. Patients with a complicated early postoperative course had a longer PICU stay (P < .001), needed longer mechanical ventilator support (P = .001) and longer inotropic support (P = .03), and more reinterventions (surgical or catheter interventional) were necessary (P = .001). Only the presence of a VSD (P = .001) and longer surgery duration (P = .026) were associated to a complicated postoperative course. TnT values only showed a trend toward higher values in patients with a complicated postoperative course (P = .06). A secondary rise in TnT was seen in 10 patients, ranging from 11.6% to 410.2%, of whom 7 could be classified in the complicated postoperative group.

CONCLUSIONS

The postoperative course after ASO in dTGA neonates is influenced by other cardiac comorbidities like a VSD with the need for surgical treatment, influencing surgery duration. Postoperative higher TnT values reflect a longer and more vulnerable intraoperative course with limited predictive value on the early postoperative course.

Cardiac injury biomarkers in paediatric age: Are we there yet?

The aim of this article is to evaluate the clinical utility of cardiac injury biomarkers in paediatric age. In December 2015, a literature search was performed (PubMed access to MEDLINE citations; http://www.ncbi.nlm.nih.gov/PubMed/ ). The search strategy included the following medical subject headings and text terms for the key words: "cardiac injury biomarkers", "creatine kinase-MB", "myoglobin", "troponin", "children", "neonate/s", "newborn/s", "infant/s" and echocardiography. In the paediatric population, troponins show a good correlation with the extent of myocardial damage following cardiac surgery and cardiotoxic medication and can be used as predictors of subsequent cardiac recovery and mortality. Elevation of cardiac injury biomarkers may also have diagnostic value in cases when cardiac contusion or pericarditis is suspected. Cardiac injury biomarkers are very sensitive markers for the detection of myocardial injury and have been studied in healthy newborns, after tocolysis, intrauterine growth restriction, respiratory distress and asphyxia. The proportion of newborns with elevated troponin was higher than that in ill infants, children, and adolescents and in healthy adults, suggesting that myocardial injury, although clinically occult, is common in this young age group. Results suggest that significant elevation of cord troponin is an excellent early predictor of severity of hypoxic-ischaemic encephalopathy and mortality in term infants. Cardiac biomarkers may also benefit centres without on-site echocardiography with evidence showing good correlation with echo-derived markers of myocardial function. Further studies are needed to better clarify the role of cardiac biomarkers in paediatric age and their correlation with echocardiographic parameters.

Prognostic value of troponin in infants with hypoplastic left heart syndrome between Stage I and II of palliation

Background

The period between stage I and II procedure for treatment of hypoplastic left heart syndrome (HLHS) bears high mortality and morbidity.

Methods

We sought to analyze the prognostic value of Troponin T/I (Trop), a well-recognized marker for myocardial damage and heart failure, for predicting outcome in a retrospective analysis of 70 infants with HLHS at our institution between March 2001 and October 2014.

Results

Stage I procedure consisted of Norwood I operation in 35 (50%) and Hybrid-approach in 22 (31%) patients. Palliative care was chosen for 13 (19%) patients. Trop values were collected from clinical charts and were analyzed in relation to the overall outcome. Trop was significantly higher after Norwood I operation in comparison to Hybrid-approach (median 7.1 μg/l (0.7-20.9), vs 1.2 μg/l (0.3-17.9), P < 0.001). Overall mortality of treated patients was 39% (22 patients). Survival was 54% (19 patients) after Norwood and 73% (16 patients) after Hybrid-approach. Independently from the procedure used, maximal Trop and initial lactate values were significantly higher in non-survivors than in survivors, with median Trop of 9 μg/l (0.6-18.8) vs. 3.4 μg/l (0.4-20.9), P 0.007, and median lactate of 3.7 mmol/L (1.6-25) vs. 2.9 mmol/L (0.3-14.6), p 0.03. Reinterventions were required in 17 (30%) patients, 4 (11%) after Norwood and 13 (59%) after Hybrid procedure. No correlation was found between the need for reintervention and Trop levels in the interstage period.

Conclusions

Patients with HLHS have significantly higher Trop levels after Norwood procedure than after Hybrid-approach. Maximal Trop values were related to mortality, but did not correlate with the need for reinterventions.

Human neonatal thymectomy induces altered B-cell responses and autoreactivity

An association between T‐cell lymphopenia and autoimmunity has long been proposed, but it remains to be elucidated whether T‐cell lymphopenia affects B‐cell responses to autoantigens. Human neonatal thymectomy (Tx) results in a decrease in T‐cell numbers and we used this model to study the development of autoreactivity. Two cohorts of neonatally thymectomized individuals were examined, a cohort of young (1–5 years post‐Tx, n = 10–27) and older children (>10 years, n = 26), and compared to healthy age‐matched controls. T‐cell and B‐cell subsets were assessed and autoantibody profiling performed. Early post‐Tx, a decrease in T‐cell numbers (2.75 × 10⁹/L vs. 0.71 × 10⁹/L) and an increased proportion of memory T cells (19.72 vs. 57.43%) were observed. The presence of autoantibodies was correlated with an increased proportion of memory T cells in thymectomized children. No differences were seen in percentages of different B‐cell subsets between the groups. The autoantigen microarray showed a skewed autoantibody response after Tx. In the cohort of older individuals, autoantibodies were present in 62% of the thymectomized children, while they were found in only 33% of the healthy controls. Overall, our data suggest that neonatal Tx skews the autoantibody profile. Preferential expansion and preservation of Treg (regulatory T) cell stability and function, may contribute to preventing autoimmune disease development after Tx.

Cardiac Biomarkers of Low Cardiac Output Syndrome in the Postoperative Period After Congenital Heart Disease Surgery in Children

INTRODUCTION AND OBJECTIVES

To assess the predictive value of atrial natriuretic peptide, β-type natriuretic peptide, copeptin, mid-regional pro-adrenomedullin (MR-proADM) and cardiac troponin I (cTn-I) as indicators of low cardiac output syndrome in children with congenital heart disease undergoing cardiopulmonary bypass (CPB).

METHODS

After corrective surgery for congenital heart disease under CPB, 117 children (aged 10 days to 180 months) were enrolled in a prospective observational pilot study during a 2-year period. The patients were classified according to whether they developed low cardiac output syndrome. Biomarker levels were measured at 2, 12, 24, and 48 hours post-CPB. The clinical data and outcome variables were analyzed by a multiple logistic regression model.

RESULTS

Thirty-three (29%) patients developed low cardiac output syndrome (group 1) and the remaining 84 (71%) patients were included in group 2. cTn-I levels >14 ng/mL at 2hours after CPB (OR, 4.05; 95%CI, 1.29-12.64; P=.016) and MR-proADM levels>1.5 nmol/L at 24hours following CPB (OR, 15.54; 95%CI, 4.41-54.71; P<.001) were independent predictors of low cardiac output syndrome.

CONCLUSIONS

Our results suggest that cTn-I at 2hours post-CPB is, by itself, an evident independent early predictor of low cardiac output syndrome. This predictive capacity is, moreover, reinforced when cTn-I is combined with MR-proADM levels at 24hours following CPB. These 2 cardiac biomarkers would aid in therapeutic decision-making in clinical practice and would also enable clinicians to modify the type of support to be used in the pediatric intensive care unit.

Myocardial Injury in Children with Unoperated Congenital Heart Diseases

Background. Children with congenital heart diseases (CHDs) may have a risk of developing myocardial injury caused by volume and pressure overload. Objective. To evaluate the incidence of myocardial injury in children with cyanotic and acyanotic CHDs using cTnI assay and to correlate it with different hemodynamic parameters. Methods. This study included 80 children with CHDs (40 acyanotic and 40 cyanotic) as well as 40 healthy children (control group). Serum cTnI levels were measured for patients and control. Pulmonary to systemic blood flow (Qp/Qs) and pulmonary to systemic arterial pressure (Pp/Ps) ratios were measured for children with CHDs during cardiac catheterization. Results. Sixty-four out of 80 patients with CHDs had myocardial injury as evidenced by increased cTnI. Serum cTnI was significantly higher in both cyanotic and acyanotic groups compared to control group (p < 0.05). Serum cTnI level significantly correlated with oxygen saturation (SpO₂), ejection fraction (EF), Qp/Qs, and Pp/Ps ratios. Conclusion. The incidence of myocardial injury was high in children with CHDs. The use of cTnI for follow-up of children with CHDs may help early detection of myocardial injury and help early management of these cases.

Intracoronary autologous cardiac progenitor cell transfer in patients with hypoplastic left heart syndrome: the TICAP prospective phase 1 controlled trial

RATIONALE

Hypoplastic left heart syndrome (HLHS) remains a lethal congenital cardiac defect. Recent studies have suggested that intracoronary administration of autologous cardiosphere-derived cells (CDCs) may improve ventricular function.

OBJECTIVE

The aim of this study was to test whether intracoronary delivery of CDCs is feasible and safe in patients with hypoplastic left heart syndrome.

METHODS AND RESULTS

Between January 5, 2011, and January 16, 2012, 14 patients (1.8±1.5 years) were prospectively assigned to receive intracoronary infusion of autologous CDCs 33.4±8.1 days after staged procedures (n=7), followed by 7 controls with standard palliation alone. The primary end point was to assess the safety, and the secondary end point included the preliminary efficacy to verify the right ventricular ejection fraction improvements between baseline and 3 months. Manufacturing and intracoronary delivery of CDCs were feasible, and no serious adverse events were reported within the 18-month follow-up. Patients treated with CDCs showed right ventricular ejection fraction improvement from baseline to 3-month follow-up (46.9%±4.6% to 52.1%±2.4%; P=0.008). Compared with controls at 18 months, cardiac MRI analysis of CDC-treated patients showed a higher right ventricular ejection fraction (31.5%±6.8% versus 40.4%±7.6%; P=0.049), improved somatic growth (P=0.0005), reduced heart failure status (P=0.003), and lower incidence of coil occlusion for collaterals (P=0.007).

CONCLUSIONS

Intracoronary infusion of autologous CDCs seems to be feasible and safe in children with hypoplastic left heart syndrome after staged surgery. Large phase 2 trials are warranted to examine the potential effects of cardiac function improvements and the long-term benefits of clinical outcomes.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01273857.