Cardiac troponin I in pediatrics: normal values and potential use in the assessment of cardiac injury

Fifteen-minute consultation on excluding cardiac causes of chest pain

Chest pain can be an extremely worrying symptom for children and parents, but is typically benign and rarely cardiac in origin. It can become problematic for paediatricians in acute care balancing parental expectations and not missing sinister causes. In addition, ordering unnecessary tests can be expensive, can lead to a prolonged hospital stay and unnecessary referrals to clinics. The aim of this review is to give an overview of the common causes of chest pain in children and how to identify cardiac causes using case vignettes.

Electrocardiography in Children Hospitalized for COVID-19 and Not Suffering from Multisystem Inflammatory Syndrome in Children (MIS-C): An Observational Study

The risk of cardiac involvement with electrophysiological abnormalities during COVID-19 infection has been reported in adults but remains poorly studied in children. Our aim was to determine the frequency of cardiac involvement and the necessity of routine cardiac evaluation in children hospitalized for COVID-19. This observational study included 127 children, with a median (IQR) age of 2 (0.83-6.0) years, who were hospitalized for COVID-19 between 1 January 2021 and 31 August 2022, 62 (48.8%) of whom were males. Each patient underwent an ECG on admission and discharge as well as a laboratory assessment. A comparison between patients with COVID-19 and healthy controls showed significantly higher HR (p < 0.0001) and lower PR values (p = 0.02) in the first group. No arrhythmias or other electrocardiographic abnormalities were detected during hospitalization. The median levels of troponin, NT-proBNP, ferritin, and D-dimer were significantly higher in children aged <2 years, but they fell within the normal range for their age. Our results indicate that a detectable cardiac involvement is very rare in children hospitalized for COVID-19 and not suffering from Multisystem Inflammatory Syndrome in Children (MIS-C) and suggest that routine electrocardiographic assessment is not mandatory in these patients in the absence of cardiac symptoms/signs.

High-Sensitivity Troponin T Testing for Pediatric Patients in the Emergency Department

Debate exists on the usefulness of high-sensitivity cardiac troponin (hs-cTn) testing in pediatric patients due to the perceived low incidence of myocardial injury and lack of data concerning its efficacy. We evaluated the contribution of an increased hs-cTnT above the 99th percentile upper-reference limit (URL) to clinical diagnoses made in pediatric patients presenting to the emergency department (ED). Retrospective cohort study including patients aged 0-18 years presenting to the ED from 2018 to 2020 where hs-cTnT was measured. Sex-specific 99th percentile URLs of 15 and 10 ng/L for males and females, respectively, were used, with concentrations above these thresholds considered indicative of myocardial injury. Overall, 356 patients were identified in whom hs-cTnT concentrations were measured during ED clinical evaluation. Hs-cTnT was increased above the 99th percentile on presentation in 36 patients (10.1%). Twelve patients (3.4%) had a clinical cardiac diagnosis made. Hs-cTnT was increased in 6 of these (50.0%). Serial hs-cTnT from 106 patients with an initial hs-cTnT < 99th percentile was subsequently elevated in 5 (4.6%); none of whom had a final clinical cardiac diagnosis. Hs-cTnT has high specificity, but low sensitivity when used as a screening tool for myocardial injury when the gold standard is mostly clinical assessment. In present practice, however, they do not appear to track well with clinical diagnoses. Further studies are needed to more clearly define the role of hs-cTnT in this patient population.

Cardiovascular magnetic resonance imaging in children after recovery from symptomatic COVID-19 or MIS-C: a prospective study

BACKGROUND

Cardiac evaluations, including cardiovascular magnetic resonance (CMR) imaging and biomarker results, are needed in children during mid-term recovery after infection with SARS-CoV-2. The incidence of CMR abnormalities 1-3 months after recovery is over 50% in older adults and has ranged between 1 and 15% in college athletes. Abnormal cardiac biomarkers are common in adults, even during recovery.

METHODS

We performed CMR imaging in a prospectively-recruited pediatric cohort recovered from COVID-19 and multisystem inflammatory syndrome in children (MIS-C). We obtained CMR data and serum biomarkers. We compared these results to age-matched control patients, imaged prior to the SARS-CoV-2 pandemic.

RESULTS

CMR was performed in 17 children (13.9 years, all ≤ 18 years) and 29 age-matched control patients without SARS-CoV-2 infection. Cases were recruited with symptomatic COVID-19 (11/17, 65%) or MIS-C (6/17, 35%) and studied an average of 2 months after diagnosis. All COVID-19 patients had been symptomatic with fever (73%), vomiting/diarrhea (64%), or breathing difficulty (55%) during infection. Left ventricular and right ventricular ejection fractions were indistinguishable between cases and controls (p = 0.66 and 0.70, respectively). Mean native global T1, global T2 values and segmental T2 maximum values were also not statistically different from control patients (p ≥ 0.06 for each). NT-proBNP and troponin levels were normal in all children.

CONCLUSIONS

Children prospectively recruited following SARS-CoV-2 infection had normal CMR and cardiac biomarker evaluations during mid-term recovery. Trial Registration Not applicable.

Big Tests in Little People

Can laboratory tests that are routinely used in adult patients also be used in pediatric patients? Does the current literature support the routine use of troponin, brain natriuretic peptide, D-dimer, and lactate in children? Adult problems such as acute coronary syndrome and pulmonary embolism are rare in pediatrics, and there is a paucity of literature on how blood tests commonly used to help diagnose these conditions in adults play a role in the diagnosis and management of children. This article presents the literature about 4 common blood tests and examines the clinical applications of each.

Evaluation of conventional troponin I testing for the detection of myocardial dysfunction in children

Objectives

Troponin is a marker of myocardial injury but is not well studied in children. Our primary objective was to ascertain the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of conventional troponin I for the detection of acute myocardial dysfunction in previously healthy children. Our secondary objective was to identify clinical predictors of myocardial dysfunction in the setting of elevated troponin.

Study Design

This was a retrospective chart review in a single, paediatric, tertiary care centre of troponin tests performed in all admitted children over a 4-year period. Demographics, symptoms, signs, chest x-ray, ECG, and echocardiogram abnormalities were documented. Myocardial dysfunction was presumed to be absent when the patient had a normal cardiac assessment, with or without echocardiography, and did not re-present.

Results

From January 2014 through December 2017, 566 patients had troponin tested as a screen for myocardial injury. Troponin was positive in 38 of 566 cases (6.7%). Myocardial dysfunction was detected in 9 of 566 cases (1.6%). Troponin was elevated in six of nine cases of myocardial dysfunction. The sensitivity of conventional troponin I for detecting acute myocardial dysfunction was 66% (95% confidence interval [CI] 30 to 93%). The specificity was 94% (95% CI 92 to 96%). PPV was 16% (95% CI 6 to 31%) and NPV 99% (95% CI 98 to 100%). An abnormal ECG was more prevalent in patients with a true positive versus a false-positive troponin result (P=0.03).

Conclusion

Troponin testing identified few cases of myocardial dysfunction. We found the test to have only 66% sensitivity. Troponin testing as a screen for myocardial injury in children has limited utility.

Laboratory Markers in the Management of Pediatric Polytrauma: Current Role and Areas of Future Research

Severe trauma is the most common cause of mortality in children and is associated with a high socioeconomic burden. The most frequently injured organs in children are the head and thorax, followed by the extremities and by abdominal injuries. The efficient and early assessment and management of these injuries is essential to improve patients' outcome. Physical examination as well as imaging techniques like ultrasound, X-ray and computer tomography are crucial for a valid early diagnosis. Furthermore, laboratory analyses constitute additional helpful tools for the detection and monitoring of pediatric injuries. Specific inflammatory markers correlate with post-traumatic complications, including the development of multiple organ failure. Other laboratory parameters, including lactate concentration, coagulation parameters and markers of organ injury, represent further clinical tools to identify trauma-induced disorders. In this review, we outline and evaluate specific biomarkers for inflammation, acid-base balance, blood coagulation and organ damage following pediatric polytrauma. The early use of relevant laboratory markers may assist decision making on imaging tools, thus contributing to minimize radiation-induced long-term consequences, while improving the outcome of children with multiple trauma.

Levosimendan treatment in a child with treatment-resistant left ventricular systolic dysfunction after scorpion sting

Background:

Scorpion stings are common in countries dominated by rural and coastal settlements with temperate climate. Scorpion stings are usually harmless and can be seen in local findings, but in some cases, systemic, neurotoxic, and cardiotoxic findings can be seen.

Case report:

A 3 year 7 month old girl was referred to pediatric emergency care 2 h after yellow scorpion (species of Leiurus abdullahbayrami) sting. In our case, cardiac function insufficiently progressed in spite of the standard inotropic and milrinone treatment. On the third day of hospitalization, levosimendan was initiated with good clinical effect.

Conclusion:

In the literature, the use of levosimendan in pediatric patients has been limited to those with low cardiac output syndrome after cardiovascular surgery. The use of levosimendan in children with scorpion sting has been previously reported only in Banille et al.’s study. Scorpion antivenom should be administered intravenously as soon as possible in cases of systemic findings that develop after scorpion stings. This report suggests that levosimendan is temporally associated with improvement in patients who have severe cardiac dysfunction due to scorpion sting and refractory to current treatment.

The Prognostic Value of Troponin in Pediatric Polytrauma

Introduction: Severe trauma accounts for a great number of deaths among children and adolescents. The diagnostic value of troponin serum levels of severely injured patients has been reported for adults, but data on pediatric polytrauma (PT) are scarce. Therefore, we conducted a retrospective monocentered study analyzing the prognostic value of troponin T (TnT) in pediatric trauma patients at the time point of hospital admission. Methods: Data of 88 polytraumatized pediatric patients admitted to the emergency room of the University Hospital of Ulm, Germany, between 2007 and 2016 were analyzed retrospectively. The data source was the written and digital patient records. Interleukin-6 (IL-6), creatine kinase activity (CK activity), and lactate and TnT levels were measured by a certified clinical diagnostic laboratory; and patients were stratified for the Injury Severity Score (ISS). The prognostic value for lung contusion, organ dysfunction, and fatal outcome was statistically explored. The study was approved by the independent ethical committee of the University of Ulm (#44/18). Results: TnT levels were significantly increased in patients after severe PT compared with mild or moderate trauma severity as assessed by ISS values. Patients with TnT levels above the cutoff showed significantly increased levels of IL-6 and CK activity and a significantly prolonged stay in the intensive care unit. However, TnT levels did not correlate with absolute ISS values. TnT levels were significantly increased in patients with chest trauma and lung contusion. The incidence of lung contusion was associated with elevation of TnT. So was the onset of organ dysfunction, defined as a Sequential Organ Failure Assessment (SOFA) score ≥ 2 and fatal outcome, with a significant enhancement of plasma levels in children with organ dysfunction and in non-survivors. Conclusion: These descriptive data suggest that evaluation of TnT on admission of multiply injured children may help in predicting severity of injury and mortality in the clinical course after trauma and thus may be a useful addition to established prognostic parameters in the future.

Neonatal Myocardial Perfusion in Right Ventricle Dependent Coronary Circulation: Clinical Surrogates and Role of Troponin-I in Postoperative Management Following Systemic-to-Pulmonary Shunt Physiology

Right ventricle dependent coronary circulation (RVDCC) in pulmonary atresia with intact ventricular septum (PA/IVS) is associated with significant mortality risk in the immediate post-operative period following the initial stage of surgical palliation. Prognosis remains guarded during the interstage period towards conversion to the superior cavopulmonary shunt physiology. Current literature is scarce regarding this specific patient population. Cardiac troponin-I is widely used as a marker of coronary ischemia in adults, but its use for routine monitoring of neonatal myocardial tissue injury due to supply/demand perfusion mismatch is, yet to be determined. We sought to evaluate the clinical correlation of cTnl perioperative use in a PA/IVS RVDCC case and assess its interplay with established clinical, echocardiographic, and laboratory variables in guiding a real-time (dynamic) management strategy following systemic-to-pulmonary shunt palliation.

Postoperative Serum Troponin Trends in Infants Undergoing Cardiac Surgery

Troponin-I (TN-I) levels are elevated following pediatric cardiac surgery with speculation that particular patterns may have prognostic significance. There is lack of procedure-specific data regarding postoperative TN-I levels in infants undergoing cardiac surgery. We hypothesized that TN-I elevation varies with type of surgery and persistent elevation predicts poor prognosis. We prospectively measured serial TN-I levels (preoperatively, 4, 8, 12, 24, and 48 hours postoperatively) in 90 infants (age < 1 year) undergoing cardiac surgery: off cardiopulmonary bypass (CPB) (n = 15), on CPB (n = 43), and on CPB with ventricular incision (CPB with ventricular incision; n = 32). All patients had undetectable baseline TN-I levels. The area under the curve of TN-I levels over the 48-hour period was significantly different among the surgical groups (P < 0.002), and highest in patients with CPB with ventricular incision. Generally, TN-I levels peaked by 4 hours after surgery and returned to near-normal levels within 48 hours. A persistent TN-I rise beyond 8 hours after surgery was a strong predictor of postoperative hypoperfusion injury (defined as a composite endpoint of end-organ injury resulting from inadequate perfusion, odds ratio 21.5; P = 0.001) and mortality (30% in those with persistently high TN-I, compared with 3.5% in the remaining patients; P < 0.001), independent of patient age, anatomy and/or complexity of surgery, and level of postoperative support. Our data provide benchmark values for TN-I levels following cardiac surgery in infants. Extent of TN-I elevation correlates with type of surgery. Persistent TN-I elevation beyond 8 hours after surgery is strongly associated with postoperative hypoperfusion injury and mortality.

Cardiac and inflammatory biomarkers in perinatally HIV-infected and HIV-exposed uninfected children

OBJECTIVES

To compare distributions of serum cardiac and inflammatory biomarkers between perinatally HIV-infected (PHIV) and perinatally HIV-exposed uninfected (PHEU) children, to evaluate their associations with echocardiographic measures, and among PHIV youth, with antiretroviral therapy (ART) and HIV disease severity measures.

DESIGN

Cross-sectional analysis of temporally paired serum samples for biomarkers and echocardiograms in a prospective multicenter cohort study of PHIV and PHEU youth.

METHODS

Serum samples were analyzed among 402 youth in the PHACS Adolescent Master Protocol (AMP) for high-sensitivity cardiac troponin-T (hs-cTnT, a cardiomyocyte injury marker), N-terminal-pro-brain natriuretic peptide (NT-proBNP, a myocardial stress marker), and inflammatory markers [high-sensitivity C-reactive protein, interleukin (IL)-1, IL-6, IL-8, IL-10, IL-18, tumor necrosis factor-α (TNF-α), and soluble TNF receptor II (sTNF-RII)]. Echocardiograms were centrally measured and parameters converted to z cores to account for differences in age and body size.

RESULTS

Compared with PHEU (N = 156), PHIV youth (N = 246) more often had detectable hs-cTnT and higher levels of sTNF-RII and IL-18. Higher inflammatory biomarkers were generally associated with higher left ventricular (LV) wall stress and lower LV function and LV mass in the two groups. Among PHIV youth, the biomarkers were more strongly associated with current rather than historical immunologic and virologic status.

CONCLUSION

PHEU and PHIV have modest, significant differences in serum levels of specific inflammatory and active myocardial injury biomarkers. Higher biomarker levels were associated with lower LV mass and shifts in LV structure. Further study is warranted on the longitudinal role of cardiac and inflammatory biomarkers for targeting interventions among PHIV and PHEU youth.

Diagnostic role of strain imaging in atypical myocarditis by echocardiography and cardiac MRI

BACKGROUND

The diagnosis of myocarditis presenting as isolated acute chest pain with elevated troponins but normal systolic function is challenging with significant drawbacks even for the gold-standard endomyocardial biopsy.

OBJECTIVE

This study aimed to evaluate the diagnostic role of strain imaging by echocardiography and cardiac MRI in these patients.

MATERIALS AND METHODS

This was a retrospective review of children with cardiac MRI for acute chest pain with elevated troponins compared to normal controls. Echocardiographic fractional shortening, ejection fraction, speckle-tracking-derived peak longitudinal, radial, and circumferential strain were compared to cardiac MRI ejection fraction, T2 imaging, late gadolinium enhancement, speckle-tracking-derived peak longitudinal strain, radial strain, and circumferential strain.

RESULTS

Group 1 included 10 subjects diagnosed with myocarditis, 9 (90%) males with a median age of 15.5 years (range: 14-17 years) compared with 10 age-matched controls in group 2. All subjects in group 1 had late gadolinium enhancement consistent with myocarditis and troponin ranged from 2.5 to >30 ng/ml. Electrocardiogram changes included ST segment elevation in 6 and abnormal Q waves in 1. Qualitative echocardiographic function was normal in both groups and mean fractional shortening was similar (35±6% in group 1 vs. 34±4% in group 2, P=0.70). Left ventricle ejection fraction by cardiac MRI, however, was lower in group 1 (52±9%) compared to group 2 at (59±4%) (P=0.03). Cardiac MRI derived strain was lower in group 1 vs. group 2 for speckle-tracking-derived peak longitudinal strain (-12.8±2.8% vs. -17.1±1.5%, P=0.001), circumferential strain (-12.3±3.8% vs. -15.8±1.2%, P=0.020) and radial strain (13.6±3.7% vs. 17.2±3.2%, P=0.040). Echocardiography derived strain was also lower in group 1 vs. group 2 for speckle-tracking-derived peak longitudinal strain (-15.6±3.9% vs. -20.8±2.2%, P<0.002), circumferential strain (-16±3% vs. -19.8±1.9%, P<0.003) and radial strain (17.3±6.1% vs. 24.8±6.3%, P=0.010).

CONCLUSION

In previously asymptomatic children, myocarditis can present with symptoms of acute chest pain suspicious for coronary ischemia. Cardiac MRI and echocardiographic strain imaging are noninvasive, radiation-free tests of immense diagnostic utility in these situations. Long-term studies are needed to assess prognostic significance of these findings.

Assessment of Myocardial Function and Injury by Echocardiography and Cardiac Biomarkers in African Children With Severe Plasmodium falciparum Malaria

OBJECTIVES

Perturbed hemodynamic function complicates severe malaria. The Fluid Expansion as Supportive Therapy trial demonstrated that fluid resuscitation, involving children with severe malaria, was associated with increased mortality, primarily due to cardiovascular collapse, suggesting that myocardial dysfunction may have a role. The aim of this study was to characterize cardiac function in children with severe malaria.

DESIGN

A prospective observational study with clinical, laboratory, and echocardiographic data collected at presentation (T0) and 24 hours (T1) in children with severe malaria. Cardiac index and ejection fraction were calculated at T0 and T1. Cardiac troponin I and brain natriuretic peptide were measured at T0. We compared clinical and echocardiographic variables in children with and without severe malarial anemia (hemoglobin < 5 mg/dL) at T0 and T1.

SETTING

Mbale Regional Referral Hospital.

PATIENTS

Children 3 months to 12 years old with severe falciparum malaria.

INTERVENTIONS

Usual care.

MEASUREMENTS AND MAIN RESULTS

We enrolled 104 children, median age 23.3 months, including 61 children with severe malarial anemia. Cardiac troponin I levels were elevated (> 0.1 ng/mL) in n equals to 50, (48%), and median brain natriuretic peptide was within normal range (69.1 pg/mL; interquartile range, 48.4-90.8). At T0, median Cardiac index was significantly higher in the severe malarial anemia versus nonsevere malarial anemia group (6.89 vs 5.28 L/min/m) (p = 0.001), which normalized in both groups at T1 (5.60 vs 5.13 L/min/m) (p = 0.452). Cardiac index negatively correlated with hemoglobin, r equals to -0.380 (p < 0.001). Four patients (3.8%) had evidence of depressed cardiac systolic function (ejection fraction < 45%). Overall, six children died, none developed pulmonary edema, biventricular failure, or required diuretic treatment.

CONCLUSIONS

Elevation of cardiac index, due to increased stroke volume, in severe malaria is a physiologic response to circulatory compromise and correlates with anemia. Following whole blood transfusion and antimalarial therapy, cardiac index in severe malarial anemia returns to normal. The majority (> 96%) of children with severe malaria have preserved myocardial systolic function. Although there is evidence for myocardial injury (elevated cardiac troponin I), this does not correlate with cardiac dysfunction.

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.

Interventricular Septal Pseudoaneurysm After Blunt Chest Trauma in a 6 Year Old: An Illustrative Case and Review

Motor vehicle accident is the most common cause of blunt cardiac injury (BCI) in children (85.3%) due to the height of the child in relation to proper restraints and the compliant pediatric rib cage (J Trauma. 1996;40:200-202). Trauma to the chest wall may lead to injury of the myocardium, resulting in myocardial contusion, ventricular septal defect (VSD), ventricular free wall rupture, or valve compromise (J Trauma. 1996;40; 200-202; Heart Lung. 2012;41:200-202; J Inj Violence Res. 2012;4:98-100). There are several proposed mechanisms for the formation of VSD after blunt chest trauma including rupture of ischemic myocardium related to the initial trauma and reopening of a spontaneously closed congenital VSD. Also, chest trauma during isovolumetric contraction of the ventricles may generate enough intraventricular force to cause myocardial rupture (J Trauma. 1996;40:200-202; J Inj Violence Res. 2012;4:98-100; Korean J Pediatr. 2011;54:86-89; Ann Thorac Surg. 2012;94:1714-1716; J Emerg Trauma Shock. 2012;5:184-187). Previous case reports highlight the formation of a true VSD after BCI and the requirement of emergent repair (J Emerg Trauma Shock. 2012;5:184-187; Am Heart J. 1996;131:1039-1041; Korean Circ J. 2011;41:625-628; Ann Thorac Surg 2013;96:297-298; Kardiol Pol. 2013;71:992; Chin Med J. 2013;126:1592-1593). Reported is a case of a 6-year-old girl who developed an interventricular septal pseudoaneurysm after a motor vehicle accident of pedestrian versus car. On the day of presentation, she developed bradycardia after emergent surgical repair for abdominal trauma that required cardiopulmonary resuscitation including 5 minutes of chest compressions. At the time of resuscitation, an emergent transthoracic echocardiogram noted an interventricular pseudoaneurysm. She has been followed with serial transthoracic echocardiograms and has not required surgical intervention. We discuss the risk factors, prevalence, and diagnostic studies and recommended treatment options for structural heart disease after BCI.

Admission Plasma Troponin I Is Associated With Mortality in Pediatric Intensive Care

OBJECTIVES

Assessment of whether admission plasma troponin I level is associated with mortality or requirement for vasoactive drugs in pediatric intensive care.

DESIGN

Retrospective cohort study.

SETTING

Single centre, tertiary referral general PICU, without a cardiac surgical program.

PATIENTS

Three hundred and nineteen patients 0-18 years old in two cohorts. Cohort 1 was admitted between January 2009 and September 2012 and the cohort 2 between April 2014 and April 2015.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma troponin I was measured in patients in cohort 1 only if the attending physician ordered the test due to clinical concern regarding myocardial injury. The second cohort had plasma troponin I routinely measured at admission. The primary outcome was death during PICU admission, and the secondary outcome was maximum inotrope requirement during PICU stay, measured by Vasoactive Inotrope Score. Plasma troponin I was a discriminator for mortality in both cohorts (area under the receiver-operating characteristic curve of 0.73 and 0.86 in cohorts 1 and 2, respectively). In an adjusted analysis using Cox regression, accounting for Pediatric Index of Mortality 2 risk of mortality and age, elevated plasma troponin I was significantly associated with death in both cohorts (hazard ratio, 4.99; p = 0.033; hazard ratio, 10.5; p = 0.026 in cohorts 1 and 2, respectively). Elevated plasma troponin I was only associated with increased Vasoactive Inotrope Score following multivariate analysis in the cohort 2.

CONCLUSIONS

Detectable plasma troponin I at admission to PICU is independently associated with death. The utility of troponin I as a stratification biomarker requires further evaluation.

Anesthesia for Pediatric Chest Trauma

Thoracic trauma in children is the second most frequent cause of death in the pediatric population. The majority of these children will have multisystem injuries. Management of these patients starts with the primary survey, resuscitation, and secondary survey as described in Advanced Trauma Life Support training. Most children with thoracic injuries can be observed or treated nonoperatively. The majority of children who do need surgery will need exploratory laparotomy and may have significant blood loss. The anesthesiologist needs to be prepared to manage a patient with severe underlying respiratory derangements, ongoing blood loss, and /or cardiac dysfunction. Moreover, one-lung ventilation may be necessary for optimal surgical exposure, which will present considerable challenges.

Proteomics of pediatric heart failure: from traditional biomarkers to new discovery strategies

Heart failure in children is a complex clinical syndrome with multiple aetiologies. The underlying disorders that lead to heart failure in children differ significantly from those in adults. Some clinical biomarkers for heart failure status and prognosis appear to be useful in both age groups. This review outlines the use and the present status of biomarkers for heart failure in paediatric cardiology. Furthermore, clinical scenarios in which development of new biomarkers might address management or prognosis are discussed. Finally, strategies for proteomic discovery of novel biomarkers and application to practice are described.

Blunt cardiac injury in critically ill trauma patients: a single centre experience

PURPOSE

This study describes the incidence and outcomes of blunt cardiac injury (BCI) in a single trauma intensive care unit (TICU), together with the spectrum of thoracic injuries and cardiac abnormalities seen in BCI.

METHODS

We performed a retrospective observational study of 169 patients with blunt thoracic trauma admitted from January 2010 to April 2013. BCI was diagnosed using an elevated serum troponin in the presence of either clinical, ECG or transthoracic echocardiography (TTE) abnormalities in keeping with BCI. The mechanism of injury, associated thoracic injuries and TTE findings in these patients are reported.

RESULTS

The incidence of BCI among patients with blunt thoracic trauma was 50% (n=84). BCI patients had higher injury severity scores (ISS) (median 37 [IQR 29-47]; p=0.001) and higher admission serum lactate levels (median 3.55 [IQR 2.4-6.2], p=0.008). In patients with BCI, the median serum TnI level was 2823ng/L (IQR 1353-6833), with the highest measurement of 64950ng/L. TTEs were performed on 38 (45%) patients with BCI, of whom 30 (79%) had abnormalities. Patients with BCI had a higher mortality (32% vs. 16%; p=0.028) and trended towards a longer length of stay (17.0 days [standard deviation (SD) 13.5] vs. 13.6 days [SD 12.0]; p=0.084).

CONCLUSIONS

BCI was associated with an increased mortality and a trend towards a longer length of stay in this study. It is a clinically relevant diagnosis which requires a high index of suspicion. Screening of high risk patients with significant blunt thoracic trauma for BCI with serum troponins should be routine practise. Patients diagnosed with BCI should undergo more advanced imaging such as TTE or TOE to exclude significant cardiac structural injury.

Chest pain in two athletic male adolescents mimicking myocardial infarction

Acute chest pain with elevated troponin and CK-MB levels and focal ST elevation on electrocardiogram is considered to be myocardial infarction unless proven otherwise. The cardiac enzymes can be elevated in other etiologies of chest pain including myopericarditis, pulmonary embolism, acute rheumatic fever, and trauma. Therefore, patients presenting with chest pain and elevated cardiac enzymes should be carefully evaluated for other etiologies after ruling out acute coronary process. We report 2 male adolescents with myopericarditis who presented to the emergency department with chest pain and elevated cardiac enzymes.

Elevated troponin levels in previously healthy children: value of diagnostic modalities and the importance of a drug screen

BACKGROUND

Myocardial injury in previously healthy children is rare, with a wide range of aetiologies. It is increasingly being identified on the basis of elevated troponin levels during routine evaluation of cardiorespiratory symptoms. Establishing the aetiology remains challenging because of the lack of an accepted work-up algorithm. Our objective was to delineate the contribution of diagnostic modalities and troponin patterns towards the final diagnosis.

METHODS

A retrospective chart review of previously healthy patients admitted to the Pediatric Cardiology Service with myocardial injury was carried out. Data analysed included echocardiograms, electrocardiograms, cardiac catheterisations, magnetic resonance imaging, drug screen tests, troponin values, and final diagnosis.

RESULTS

A total of 32 patients were identified. The diagnoses were: myocarditis in 16 patients, vasospasm due to drug use in seven, myopericarditis in six, anomalous coronary artery origins in two, and Prinzmetal's angina in one patient. The electrocardiograms were abnormal in 27 of the 32 patients (84%), echocardiograms in 18 of the 32 patients (56%), cardiac magnetic resonance imaging in two of the four patients (50%), urine drug screen in five of the 25 patients (20%), and cardiac catheterisations in two of the 15 patients (13%).

CONCLUSIONS

Myocarditis is the most common aetiology of myocardial injury in children. Clinical history remains the basic screening tool; drug screens help identify coronary vasospasms secondary to drug use (22% of our cohort). Patients with anomalous coronaries had exertional symptoms. Initial troponin levels and progression were not diagnostic or prognostic. Catheterisation is of limited value and did not change management. Magnetic resonance imaging with gadolinium enhancement is probably the most useful test when initial evaluation is not diagnostic.

The influence of age on serum concentrations of cardiac troponin I: results in rats, monkeys, and commercial sera

Cardiac troponins serve as serum biomarkers of myocardial injury. The current study examined the influence of age on serum concentrations of cardiac troponin I (cTnI). An ultrasensitive immunoassay was used to monitor cTnI concentrations in Sprague-Dawley (SD) rats and Erythrocebus patas monkeys of different ages. The mean cTnI concentrations were highest in 10-day-old rats compared to 25-, 40-, and 80-day-old SD rats. Cardiomyocyte remodeling was apparent in hearts from 10-day-old SD rats as evident by hypercellularity, irregularly shaped nuclei, and moderate numbers of myocytes undergoing mitosis and apoptosis. The mean concentration of cTnI in 5 newborn monkeys was considerably higher than that of three 1-year-old monkeys. Evidence of cardiomyocyte remodeling was also observed in these newborn hearts (loss of myofibrils and cytoplasmic vacuolation). Commercial animal serum samples were also analyzed. The concentrations of cTnI detected in fetal equine and porcine serum were considerably higher than that found in adult equine and porcine serum samples Likewise, fetal bovine serum had higher cTnI concentrations (>2,400 pg/ml) than did adult caprine and laprine samples (2.5-2.7 pg/ml). The present study found age-related differences in cTnI concentrations, with higher levels occurring at younger ages. This effect was consistent across several animal species.

Diastolic hypotension is an unrecognized risk factor for β-agonist-associated myocardial injury in children with asthma

OBJECTIVES

Tachycardia and diastolic hypotension have been associated with β-2 agonist use. In the setting of β-agonist-induced chronotropy and inotropy, diastolic hypotension may limit myocardial blood flow. We hypothesized that diastolic hypotension is associated with β-agonist use and that diastolic hypotension and tachycardia are associated with biochemical evidence of myocardial injury in children with asthma.

DESIGN

Two patient cohorts were collected. The first, consisting of patients transported for respiratory distress having received at least 10 mg of albuterol, was studied for development of tachycardia and hypotension. The second, consisting of patients who had troponin measured during treatment for status asthmaticus with continuous albuterol, was studied for factors associated with elevated troponin. Exclusion criteria for both cohorts included age younger than 2 years old, sepsis, pneumothorax, cardiac disease, and antihypertensive use. Albuterol dose, other medications, and vital signs were collected. Diastolic and systolic hypotension were defined as an average value below the fifth percentile for age and tachycardia as average heart rate above the 98th percentile for age.

PATIENTS

Ninety of 1,390 children transported for respiratory distress and 64 of 767 children with status asthmaticus met inclusion criteria.

MEASUREMENTS AND MAIN RESULTS

Diastolic hypotension occurred in 56% and 98% of the first and second cohorts, respectively; tachycardia occurred in 94% and 95% of the first and second cohorts, respectively. Diastolic hypotension and tachycardia had a weak linear correlation with albuterol dose (p = 0.02 and p = 0.005, respectively). Thirty-six percent had troponin > 0.1 ng/mL (range, 0-12.6). In multivariate analysis, interaction between diastolic hypotension and tachycardia alone was associated with elevated troponin (p = 0.02).

CONCLUSIONS

Diastolic hypotension and tachycardia are dose-dependent side effects of high-dose albuterol. In high-risk patients with status asthmaticus treated with albuterol, diastolic hypotension and tachycardia are associated with biochemical evidence of myocardial injury. Diastolic hypotension, especially combined with tachycardia, could be a reversible risk factor for myocardial injury related to β-agonist use.

Management of chest trauma in children

Chest trauma in children is caused by high-energy blows, due in general to traffic accidents, that involve several other body regions. They occur mainly in the first decade of life and can be penetrating but are more often non-penetrating. Rib fractures and lung contusions, sometimes associated with pneumothorax or haemothorax, are the more usual injuries, but tracheobronchial rupture, cardiac, oesophageal or diaphragmatic injuries may also occur. These injuries are treated with supportive respiratory and haemodynamic measures, drainage of air or blood from the pleural space and, at times, surgical repair of the injured organ(s). Ruptures of the airway may be difficult to treat and occasionally require suture, anastomosis or resection. Oesophageal injuries can be treated conservatively with antibiotics, drainage and parenteral nutrition. Diaphragmatic tears should be repaired operatively. Overall mortality ranges from 6 to 20%. Mortality is high but this is mainly due to the associated presence of extra-thoracic trauma, and particularly to head injuries.

Prognostic value of troponins in sepsis: a meta-analysis

RATIONALE

The role of biomarkers such as troponin in risk stratification of sepsis is still debated. The aim of this meta-analysis is to assess the relation between troponin elevation in sepsis and mortality.

METHODS

All observational studies from Embase, Medline and those manually searched up to September 2010 were included. Studies identified were those which reported on patients with a diagnosis of sepsis and if a 2 × 2 table could be constructed based on troponins and death. We pooled the relative risk (RR) and odds-ratio (OR) using the inverse variance method in studies that conducted univariate and multivariable (adjusted) analysis.

MAIN RESULTS

Thirteen studies encompassing 1,227 patients were included. The prevalence of elevated troponin was 61 % ([95 %] CI 58-64 %). Elevated troponin was significantly associated with all-cause mortality (RR 1.91; CI 1.63-2.24), with homogeneity across studies. In adjusted analysis (four studies comprising 791 patients) according to prognostic scores, elevated troponin was associated with an increased risk of death (OR 1.92; CI 1.35-2.74). The area under the ROC curve was 0.68 (CI 0.63-0.71). Pooled sensitivity and specificity were 77 % (CI 61-88) and 47 % (CI 30-64) with heterogeneity across studies. It corresponded to positive and negative likelihood ratios of 1.50 (95 % CI: 1.20-1.90) and 0.49 (CI 0.38-0.64), respectively.

CONCLUSIONS

Elevated troponin identifies a subset of patients with sepsis at higher risk of death. Further studies are needed to define the precise role of troponins and their optimal cut-offs.

Serum troponin-I as an indicator of clinically significant myocardial injury in paediatric trauma patients

Myocardial injury is a cause of mortality in paediatric trauma, but it is often difficult to diagnose. The objectives of this pilot study were to (1) determine the prevalence of elevated cardiac troponin I (TnI) in paediatric trauma patients and (2) to determine whether elevated TnI correlates with clinically significant myocardial injury, defined as abnormalities on echocardiogram (ECHO) and/or electrocardiograms (ECG). To this end, we investigated a convenient sample size of 59 paediatric trauma patients with an Injury Severity Score (ISS)>12. TnI and creatine kinase-MB (CK-MB) were measured on admission, at then at regular intervals until TnI had normalized. Patients with elevated TnI levels had an ECHO performed within 24h of admission and underwent daily ECGs until TnI normalized. Elevated serum TnI was found in n=16/59 (27%; 95% CI: 18-40%) patients and was associated with elevated CK-MB in all cases. Abnormal ECHOs were seen in 4/16 patients with elevated TnI, but peak TnI values did not correlate with abnormalities on ECHO (p=0.23). Only 1 patient had a clinically significant, albeit mild, decrease in cardiac function. All ECGs were normal. Patients with elevated TnI were more likely to be intubated (p=0.04), to have higher Injury Severity Scores (p=0.02), required more resuscitation fluid (p=0.001), and to have thoracic injuries (p<0.001). Our data indicates that the prevalence of elevated TnI in paediatric trauma patients is 27%; and whilst elevated TnI reflects overall trauma severity, it is frequently elevated without a clinically significance myocardial injury. Hence, large scale studies are required to determine if an elevated threshold TnI value can be identified to accurately diagnose severe myocardial injury in paediatric trauma.

Use and misuse of serum troponin assays in pediatric practice

Cardiac troponin (cTn) is instrumental in screening and diagnosing myocardial ischemia in adults. However, the role of cTn screening in the pediatric population is less clear. The purpose of this study was to evaluate the current clinical practice, diagnostic and prognostic value, and resource utilization associated with cTn assays in the pediatric population. A multicenter, retrospective review of all cTn assays performed on patients aged ≤18 years from January 2003 to December 2010 in the Intermountain Healthcare system was conducted. Data collected included patient demographics, location, presenting symptoms, provisional and discharge diagnoses, additional tests, clinical outcomes (hospitalization days, ventilation, and death), and patient charges. During the study period, cTn assays were performed on 3,497 pediatric patients. The most common presenting diagnoses were chest pain (40%), trauma (11%), and poisoning or drug overdose (9%). Irrespective of diagnosis, elevated cTn was associated with an increased rate of hospitalization, ventilation, and death. Overall, 12% of patients had elevated cTn. Of the patients with chest pain, 4% had elevated cTn, 53% of whom were diagnosed with myopericarditis. In the myopericarditis group, 66% presented with fever, and 98% had abnormal electrocardiographic findings. For patients presenting with chest pain, approximately $162,000 was spent per positive result. In conclusion, cTn screening has strong prognostic value in pediatric patients, even in noncardiac diagnoses such as trauma or drug overdose. However, cTn screening in pediatric patients with chest pain provides minimal benefits and is associated with increased resource utilization, unless patients have constitutional symptoms, such as fever and/or electrocardiographic abnormalities.

The evaluation of diagnostic role of cardiac troponin T (cTnT) in newborns with heart defects

Heart diseases are a significant cause of morbidity and mortality in newborns. Diagnostic methods are often not sufficient or, in many cases, cannot be used. There is a great advance in medical knowledge concerning biomarkers in the diagnosis of circulatory system in adult patients. Among them, cardiac troponins play the main role. In current literature, there is not enough data concerning the possibility of using them in neonatal cardiac diagnostics. Aim of the Study. To evaluate diagnostic usefulness of cTnT in correlation with other markers of circulatory failure and myocardial damage in newborns with heart defects. Patients and Methods. The study involved 83 newborns up to 46 weeks of postmenstrual age. The exclusion criteria were severe perinatal asphyxia and presence of severe noncardiac diseases. Patients were divided into 2 main groups: group I—54 patients with congenital heart defects (CHDs), and group II (control)—29 healthy neonates. All patients underwent detailed examination of circulatory system. Cardiac troponin T (cTnT) concentrations were evaluated by Roche CARDIAC T Quantitive test. Results. Performed studies revealed that cTnT levels in newborns with heart pathology were significantly higher than in healthy ones. However, cTnT concentrations in patients with CHD did not correlate with clinical symptoms of heart failure, nor with echocardiographic markers of LV function. Type of heart defect did not influence cTnT levels as well. Only hemodynamic significance evaluated by echocardiography influenced the cTnT levels with statistical significance. Conclusions. (1) Statistically significant differences in cTnT levels between newborns with heart defects and healthy subjects were shown. (2) CTnT levels in newborns with heart defects refer only to hemodynamic significance of the defect.

Use of troponin as a screen for chest pain in the pediatric emergency department

Troponin levels are commonly employed in the assessment of adults presenting with chest pain or concern for coronary ischemia. However, the utility of troponin measurements in children is not well defined. The purpose of this study was to review the use and clinical yield of serum troponin assay in a large pediatric emergency department (ED). We identified all patients <22 years of age, not previously known to have cardiac disease, who presented with chest pain and whose troponin levels were evaluated in our pediatric ED during a 7-year period. Test results were correlated to patient factors, such as chief complaint, cardiac history, diagnostic workup, and discharge diagnoses. Of the 212 study patients who presented with chest pain, troponin levels were increased (≥ 0.1 ng/ml) in 37 (17%) subjects. The disposition for these 37 subjects included transfer to adult facility (n = 6), admission to our pediatric inpatient service (n = 27), and discharge to home from the ED (n = 10). Only one subject had an acute myocardial infarction. For those with increased troponin level, 18 of 37 (48%) cases were attributed to a primary cardiac diagnosis with the most common discharge diagnosis of myocarditis or pericarditis. In the pediatric ED setting, selective use of troponin assay may be a useful test in the management of patients with chest pain. Most cases of increased troponin level related to chest pain represent myocarditis, often mild and self-resolving. Given the low likelihood that acute coronary syndrome is the etiology of chest pain, immediate transfer to an adult facility for the majority of patients with increase of troponin does not appear warranted.

Dexamethasone pretreatment provides antiinflammatory and myocardial protection in neonatal arterial switch operation

BACKGROUND

This prospective double-blinded randomized study tested the hypothesis that preoperative treatment with dexamethasone would attenuate inflammatory priming of the myocardium, reduce the systemic inflammatory reaction upon cardiac operation, and provide organ protection in neonates.

METHODS

Twenty neonates (age, 8 to 21 days) with transposition of the great arteries scheduled for arterial switch operation were included. Nine received dexamethasone (1 mg/kg body weight) 4 hours before cardiopulmonary bypass, and 11 received natrium chloride. We studied intramyocardial messenger RNA expression of interleukin (IL)-6, IL-8, IL-1β, and tumor necrosis factor-α (TNF-α), as well as IL-10 and expression of TNF-α on protein level in right atrial tissue taken before institution of CPB. We measured plasma levels of IL-6, IL-10, lipopolysaccharide binding protein, and cardiac troponin T. Cytokine expression was related to postoperative outcome.

RESULTS

Pretreatment with dexamethasone led to a significant decrease in myocardial expression of IL-6, IL-8, IL-1β, and TNF-α messenger RNA and to a decrease in protein synthesis of TNF-α. Plasma concentrations of IL-6 were significantly lower and those of IL-10 significantly higher in pretreated patients. This was associated with lower cardiac troponin T values and lower dobutamine requirement. Levels of lipopolysaccharide binding protein were significantly higher postoperatively in pretreated neonates.

CONCLUSIONS

Dexamethasone administration before arterial switch operation leads to a shift in the myocardial and systemic cytokine expression profile in neonates with transposition of the great arteries, with downregulation of proinflammatory and upregulation of antiinflammatory cytokines. Lower myocardial cell damage and lower catecholamine requirement suggest myocardial protection in treated patients.

A meta-analysis of the biomarkers associated with coronary artery lesions secondary to Kawasaki disease in Chinese children

The biomarkers associated with coronary artery lesions (CAL) secondary to Kawasaki disease (KD) in Chinese children were investigated by using Meta-analysis. We searched documents published from January 1997 to December 2009 from medical electronic databases. According to inclusion and exclusion criteria, eligible full-text papers were identified. We conducted a comprehensive quantitative analysis by using Stata10.0 statistical software package to assess the heterogeneity among the documents, calculated the summary effect and analyze publication bias and sensitivity. A total of 92 documents and 16 biomarkers were identified. All documents were case-control studies, and included 2398 patients in CAL group and 5932 patients in non-CAL (NCAL) group. The Meta-analysis showed that the levels of platelet count, platelet hematocrit (PCT), neutrophils count, platelet distribution width (PDW), mean platelet volume (MPV), erythrocyte sedimentation rate (ESR), cardiac troponin I (cTnI), and endothelin-1 (ET-1) in CAL group were significantly higher than those in NCAL group, and serum albumin (Alb) and hemoglobin (Hb) levels were significantly lower in CAL group (all P<0.05). White blood cell (WBC) count, serum sodium, matrix metalloproteinase 9 (MMP-9), total cholesterol (TC), hematocrit (HCT) and CD3+T lymphocytes percentage had no statistically significant difference between the two groups. In conclusion, our results indicated that the 10 biomarkers including platelet count, neutrophils count, PCT, PDW, MPV, ESR, cTnI, ET-1, Alb and Hb were associated with CAL, and may be involved in the pathogenesis of CAL. The biomarkers of WBC count, serum sodium, MMP-9, TC, HCT, and CD3+T lymphocytes percentage bore no relationship with the development of CAL among Chinese children with KD.

Elevated cardiac troponin I level in cases of thoracic nonaccidental trauma

BACKGROUND

Injury patterns in nonaccidental trauma (NAT) often include injury to the chest. However, signs and symptoms of cardiac insult are often nonspecific and may be missed. Evaluation with serum cardiac troponin I (CTnI), a specific indicator of myocardial injury, could improve the comprehensive evaluation of patients with suspected NAT.

OBJECTIVE

The objective of this study was to describe the patient characteristics and results of CTnI testing in children with thoracic NAT.

METHODS

Children presenting to the emergency department were included if CTnI was obtained and they had at least one of the following: history of blunt trauma to the chest, bruising or abrasions to the chest, or fractures of the ribs, sternum, or clavicles. A serum CTnI level above 0.04 ng/mL was considered elevated.

RESULTS

Ten patients (6 males) with an age range from 2 months to 4 years (mean [SD], 20 [20] months) were identified during the 17-month study period. All patients were evaluated with NAT. Cardiac troponin I level was elevated in 7 (70%) of 10 patients with levels between 2 and 50 times the upper limit of normal.

CONCLUSIONS

This report is the first to document elevation of CTnI levels in cases of thoracic NAT. The elevation of the level of this specific biomarker may be indicative of sufficient chest trauma to result in the heart being injured, independent of the presence of cardiac decompensation or shock from other causes. Prospective evaluation of the forensic and clinical use of CTnI in this population is warranted.

Biomonitors of cardiac injury and performance: B-type natriuretic peptide and troponin as monitors of hemodynamics and oxygen transport balance

Serum biomarkers, such as B-type natriuretic peptide and troponin, are frequently measured in the cardiac intensive care unit. A review of the evidence supporting monitoring of these biomarkers is presented.

DESIGN

A search of MEDLINE, PubMed, and the Cochrane Database was conducted to find literature regarding the use of B-type natriuretic peptide and troponin in the cardiac intensive care setting. Adult and pediatric data were considered.

RESULTS AND CONCLUSION

Both B-type natriuretic peptide and troponin have demonstrated utility in the intensive care setting but there is no conclusive evidence at this time that either biomarker can be used to guide inpatient management of children with cardiac disease. Although B-type natriuretic peptide and troponin concentrations can alert clinicians to myocardial stress, injury, or hemodynamic alterations, the levels can also be elevated in a variety of clinical scenarios, including sepsis. Observational studies have demonstrated that perioperative measurement of these biomarkers can predict postoperative mortality and complications.

RECOMMENDATION AND LEVEL OF EVIDENCE

(class IIb, level of evidence B): The use of B-type natriuretic peptide and/or troponin measurements in the evaluation of hemodynamics and postoperative outcome in pediatric cardiac patients may be beneficial.

Early pleural effusions related to the myocardial injury after open-heart surgery for congenital heart disease

OBJECTIVES

The degree of effusion immediately after cardiopulmonary bypass (CPB) can vary and may reflect several factors including the degree of myocardial injury. We compared the degree of pleural effusions after CPB to the overall myocardial injury as determined by serum cardiac troponin I (cTnI) levels after elective repair of a variety of congenital heart defects, including univentricular surgeries via cavopulmonary shunts.

METHODS

Serum was collected pre-CPB, post-CPB, and daily after that and cTnI level measured. The postoperative pleural effusion was measured each day until the chest tube was removed. Results. The 21 study patients were of average age of 5.5 years (+/-5.6). The duration of chest-tube drainage after open-heart surgery was 4.3 days (+/-3.5) and the amount was 2.4 mL/kg/hour (+/-2.9). For the biventricular repairs, cTnI levels on the postoperative day (POD) 1 best correlated with amount of effusion (n = 16, r = 0.5, P = 0.02) and the average (POD 0-3) cTnI levels with the total duration (n = 16, r = 0.4, P = 0.01) and also the amount (n = 16, r = 0.5, P = 0.02) of effusions. For the cavopulmonary shunts, the post-CBP cTnI level best correlated with the duration (n = 5, r = 0.8, P = 0.02) and amount (n = 5, r = 0.9, P = 0.02) of effusions. A cTnI level on the first postoperative day >or=15 microg/L was associated with effusions >2 days (sensitivity of 81% and specificity of 80%).

CONCLUSION

We found that higher the cTnI released, especially >or=15 microg/L, longer the duration and greater the amount of early pleural effusions for a variety of congenital heart surgeries including cavopulmonary shunts. A number of factors may lead to excessive pleural effusions and the degree of myocardial injury may be one of them.

Clinical myocarditis masquerading as acute coronary syndrome

We report a series of children with clinical myocarditis presenting with chest pain and elevated cardiac troponin I mimicking coronary syndrome. Our series illustrates the complementary role the magnetic resonance imaging and computed tomographic angiography can play in the evaluation of these patients. Elevated cardiac troponin I levels were found to be related to the extent of myocardial involvement, but did not necessarily indicate poor prognosis in children with myocarditis.

The role of biomarkers in the early detection of anthracycline-induced cardiotoxicity in children: a review of the literature

Anthracycline-induced cardiotoxicity can cause serious health problems for an increasing number of children surviving childhood malignancies. Early detection of cardiac failure is critically important for the prevention and management of anthracycline-induced cardiotoxicity. The aim of this research was to determine the role of biomarkers in the early detection of anthracycline-induced cardiotoxicity in children. A literature review is presented of studies regarding the use of the biomarkers B-type natriuretic peptide (BNP), N-terminal pro-BNP (NT-pro-BNP), cardiac troponin T (cTnT), and cardiac troponin I (cTnI) in relation with anthracycline-induced cardiotoxicity in children. Six of 14 studies in children showed a significant relation between elevated biomarkers BNP, NT-pro-BNP, and cTnT and cardiac dysfunction. Six studies, although small, suggest that BNP, NT-pro-BNP, and cTnT might be useful markers in the early detection of anthracycline-induced cardiotoxicity.

Paediatric chest trauma (part 2) — Hidden Injuries

Chest trauma is the second greatest cause of mortality from trauma, a leading cause of death in children over the age of one. Prompt diagnosis can be difficult as the underlying thoracic injuries are often disproportionately severe compared to the visible surface injury and symptoms may not appear for several hours. Diagnosis are easily underestimated, delayed or missed. This is the second of a 2 part article reviewing Paediatric chest trauma and its current management. The injuries are usefully classified into 6 lethal injuries that need excluding in the primary survey and 6 hidden injuries that must be considered in the secondary survey. The 6 lethal injuries are covered in the first part of this article along with biomechanics and mechanisms of injury. This article looks in depth at the 6 hidden injuries, along with a review of chest trauma in non-accidental injury.

Myocardial infarction in healthy adolescents

OBJECTIVE

Chest pain in children and adolescents is a frequent cause for office or emergency department visits. However, it is unclear whether myocardial infarction occurs in children with no anatomic abnormality presenting with chest pain.

METHODS

Clinical history, electrocardiography, echocardiography, and cardiac enzyme levels were evaluated in patients presenting to the emergency department over a period of 11 years (June 1995 to May 2006). Patients in whom findings were suggestive of acute myocardial infarction, in addition, underwent drug screening, serum lipid profile, and hypercoagulability workup and, when myocardial infarction was diagnosed, heart catheterization with coronary angiography.

RESULTS

Nine patients (8 boys; age range: 12-20 years; mean: 15.5 years) met established criteria for myocardial infarction. Abnormal electrocardiograms were found in 8 patients (6 with ST elevation and 2 with nonspecific ST-T abnormalities), abnormal cardiac enzyme levels in all, and echocardiographic abnormalities in 3. Cardiac dysrhythmias were found in 4 patients, 3 with nonsustained ventricular tachycardia. Drug abuse, lipid profile, and hypercoagulability studies were negative in all. Left ventricular focal hypokinesia was seen by echocardiogram or angiography in 5 patients and abnormal coronary anatomy in none. Cardiac function normalized in 8 patients. One patient had a persistent focal inferior hypokinesis. Calcium channel blocker therapy was initiated in all of the patients with no recurrence of anginal chest pain on follow-up. One patient complained of chest pain distinct from anginal pain.

CONCLUSIONS

Myocardial infarction can occur in adolescents with normal coronary arterial anatomy. Adolescents who present for emergency care with typical chest pain need electrocardiographic and cardiac enzyme workups. Those with results that are suggestive of acute infarction require additional workup. Coronary vasodilation therapy seems helpful, but given the lack of coronary thrombosis in these patients, thrombolytic therapy seems unwarranted. Long-term follow-up is necessary, and adjustments in therapy may be required with time.

A personal history of markers of myocyte injury [myocardial infarction]

BACKGROUND

The measurement of proteins in blood to reflect damage to the heart is one of the most successful examples of easily measured biomarkers identifying a serious major health problem. The concept of using a blood test to reflect organ or cell injury requires a substance that is very abundant in the target cell, has a means of reaching blood, a reasonable half-life in blood, and ideally a specific form reflective only of the target cell in tissue. The myocyte's major role is contraction so proteins involved in contraction or the energy to support it should be good candidate markers.

CONCLUSIONS

All the various biomarkers that have been used to detect cardiac damage are involved in contraction or energy metabolism, but the markers evolved empirically starting with transaminases in the 1950s leading to troponins in the 1990s. This history is reviewed with reflections on my experiences with developing assays for CK-MB and Troponin I.

Myocardial injury in infants ventilated on the paediatric intensive care unit: a case control study

Introduction

Cardiac troponin T (cTnT) has been used to assess prevalence of myocardial injury in critically ill children. The majority of studies investigated patients undergoing cardiac surgery. Myocardial injury has been associated with increased mortality. Our objectives were to investigate whether cTnT levels are elevated in infants without congenital heart disease admitted to the paediatric intensive care unit (PICU) and whether levels are associated with increased disease severity.

Methods

We measured cTnT in consecutive infants (<12 months old) without congenital heart disease admitted to the PICU and healthy infants. The Paediatric Index of Mortality (PIM) score was determined in patients on the PICU.

Results

We recruited 107 infants: 47 infants admitted to the PICU and 60 healthy controls. Controls were, with a median (interquartile range (IQR)) age of 20 (12 to 34) weeks, significantly older than cases, with a median age of 6.5 (0.3 to 20.6) weeks. CTnT levels were, with a median (IQR) of 18 (10 to 60) pg/ml, significantly higher in admissions to the PICU than in controls, with a median level of 10 (10 to 10) pg/ml (95th centile of 20 pg/ml) (p < 0.001). There was a significant positive correlation (r = 0.41, p = 0.004) between PIM score and cTnT levels. Admissions under one month old had higher cTnT levels than older patients (p = 0.013) but the PIM score was not significantly different between them. When corrected for age and weight the correlation of PIM and cTnT was no longer significant.

Conclusion

Infants on the PICU in the neonatal period have higher cTnT levels compared to older infants despite not having more severe disease.

Cardiac troponin I serum concentrations in newborns: A study and review of the literature

BACKGROUND

Serum cardiac troponin I (cTnI) is a specific marker of cardiac injury. The use of cTnI in neonates, especially in relation to perinatal asphyxia has not been extensively examined. We defined the range of normal values of cTnI in newborns, and study factors that may influence these concentrations.

METHODS

Serum cTnI concentrations were measured on the third day of life in 179 normal newborns: 157 were term (after 37 weeks, mean: 39.7+/-1.1, range: 37-42) and 22 were premature infants (mean: 32.6+/-2.9, range: 27-36 weeks).

RESULTS

Mean cTnI for the term infants was 0.63+/-0.58 ng/ml (median: 0.50, range: 0.00-4.30). The concentration of 1.80 ng/ml, can serve as the upper limit of normal values. There was a borderline significant trend for higher cTnI in preterm infants. The number of newborns with cTnI>1.80 ng/ml was significantly higher after delivery by caesarean section, compared to vaginal delivery (14.6% vs. 2.9%, p<0.02). No other significant associations were found between cTnI and perinatal or neonatal parameters.

CONCLUSIONS

Normal reference values for cTnI in healthy term newborns were defined, but need to be addressed with caution due to the wide range of normal values.

Frequency of clinically unsuspected myocardial injury at a children's hospital

BACKGROUND

Ill children are at risk but rarely screened for myocardial injury. The frequency of such injury in ill children is unknown. Elevated levels of plasma cardiac troponin I (cTnI) can detect subclinical myocardial injury.

METHODS

We measured cTnI levels from 283 Children's Hospital, Boston patients (median age 2.10 years, range 0.13-22.4 years) seen in an outpatient or emergency clinic without clinically apparent cardiac disease. We took > or = 0.5 ng/mL as an indication of myocardial injury. We also measured plasma creatine kinase-MB, total creatine kinase, and myoglobin, and performed a chart review.

RESULTS

Fifteen (7.8%) of the 193 acutely ill children and 4 (4.4%) of the 90 well children had an elevated cTnI level (P = .44). Within the acutely ill group, the children with elevated cTnI were younger and had lower mean hemoglobin and hematocrit levels. Cardiac troponin I levels correlated with creatine kinase-MB (r = 0.22; P < .001) but not with creatine kinase or myoglobin. The 4 children with cTnI > 0.89 ng/mL, who also had plasma cardiac troponin T measured, showed cardiac troponin T elevations that were consistent with unstable angina levels in adults. Four children had high-level cTnI elevations (> 2 ng/mL) consistent with acute myocardial infarction levels in adults.

CONCLUSIONS

Elevated cTnI levels occur in children without clinically apparent cardiac disease and can be at adult unstable angina or acute myocardial infarction levels. Prospective studies to determine the clinical significance of these findings and their relationship to the development of cardiomyopathy are warranted.

Cardiac troponin I as a predictor of mortality for pediatric submersion injuries requiring out-of-hospital cardiopulmonary resuscitation

BACKGROUND

It is difficult to predict ultimate survivors to hospital discharge in children who are successfully resuscitated after a cardiorespiratory arrest associated with a submersion injury. Serum measurements of organ injury or dysfunction may serve as a surrogate marker of the degree of hypoxic injury. We designed a prospective study whose purpose was to assess the predictive value for outcome of serum cardiac troponin I measurements after submersion injury and cardiorespiratory arrest.

METHODS

This is a prospective, observational study of children admitted to a postintensive care unit after experiencing an out-of-hospital cardiorespiratory arrest associated with a submersion event. Cardiac troponin I measurements were examined upon admission to the postoperative intensive care unit after successful emergency department resuscitation.

RESULTS

Nine patients were admitted, and 2 patients (22%) survived to hospital discharge. The area under the receiver operating characteristic curve is 0.786 (95% confidence interval, 0.481-1.0). This suggests that cardiac troponin I has a moderate degree of discriminatory power in selecting children who did not survive to hospital discharge.