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

Cardiovascular Risk in Childhood Cancer Survivors

Cancer is a prominent cause of death worldwide in the pediatric population. Since childhood cancer is not possible to prevent, it is essential to focus on a prompt and correct diagnosis followed by effective, evidence-based therapy with individualized supportive care. Given the enhancement of childhood cancer management over the past decades, survival rate has significantly improved, thus leading to the progression of several late effects, including metabolic derangements. These metabolic imbalances are associated with the underlying disease and the cancer treatments. As a result, the metabolic state may contribute to a high risk of cardiovascular morbidity and premature mortality among childhood cancer survivors. This review aims to summarize the potential pathophysiological mechanisms linked to the risk of diabetes and metabolic syndrome and screening recommendations. Further investigations are needed to clarify the underlying mechanisms of such metabolic abnormalities and to improve long-term cardiometabolic survival among these patients.

Paediatric cardio-oncology: epidemiology, screening, prevention, and treatment

With 5-year survival of children with cancer exceeding 80% in developed countries, premature cardiovascular disease is now a major cause of early morbidity and mortality. In addition to the acute and chronic cardiotoxic effects of anthracyclines, related chemotherapeutics, and radiation, a growing number of new molecular targeted agents may also have detrimental effects on the cardiovascular system. Survivors of childhood cancer also may have earlier development of conventional cardiovascular risk factors such as hypertension, dyslipidaemia, and diabetes, which further increase their risk of serious cardiovascular disease. This review will examine the epidemiology of acute and chronic cardiotoxicity relevant to paediatric cancer patients, including genetic risk factors. We will also provide an overview of current screening recommendations, including the evidence regarding both imaging (e.g. echocardiography and magnetic resonance imaging) and blood-based biomarkers. Various primary and secondary prevention strategies will also be discussed, primarily in relation to anthracycline-related cardiomyopathy. Finally, we review the available evidence related to the management of systolic and diastolic dysfunction in paediatric cancer patients and childhood cancer survivors.

Reimagining What We Measure in Atherosclerosis-a "Phenotype Stack"

The term phenotype is so commonly used that we often assume that we each mean the same thing. The general definition, the set of observable characteristics of an individual resulting from the interaction of their genotype with the environment, is often left to the eye of the beholder. Whether applied to the multiple levels of biological phenomena or the intact human being, our ability to characterize, classify, and analyze phenotype has been limited by measurement deficits, computing limitations, and a culture that avoids the generalizable. With the advent of modern technology, there is the potential for a revolution in phenotyping, which incorporates old and new in structured ways to dramatically advance basic understanding of biology and behavior and to lead to major improvements in clinical care and public health. This revolution in how we think about phenotypes will require a radical change in the scale at which biomedicine operates with significant changes in the unit of action, which will have far-reaching implications for how care, translation, and discovery are implemented.

Exact Bayesian p-values for a test of independence in a 2 × 2 contingency table with missing data

Altham (Altham PME. Exact Bayesian analysis of a 2 × 2 contingency table, and Fisher's "exact" significance test. J R Stat Soc B 1969; 31: 261-269) showed that a one-sided p-value from Fisher's exact test of independence in a 2 × 2 contingency table is equal to the posterior probability of negative association in the 2 × 2 contingency table under a Bayesian analysis using an improper prior. We derive an extension of Fisher's exact test p-value in the presence of missing data, assuming the missing data mechanism is ignorable (i.e., missing at random or completely at random). Further, we propose Bayesian p-values for a test of independence in a 2 × 2 contingency table with missing data using alternative priors; we also present results from a simulation study exploring the Type I error rate and power of the proposed exact test p-values. An example, using data on the association between blood pressure and a cardiac enzyme, is presented to illustrate the methods.

Cardiovascular disease in survivors of childhood cancer

PURPOSE OF REVIEW

We review the cardiotoxic chemotherapeutic agents, the clinical and subclinical presentations and progression of their cardiotoxicity, and the management of the subsequent cardiovascular disease in survivors of childhood cancer. We discuss various preventive measures, especially the cardioprotectant, dexrazoxane, whose use with anthracycline chemotherapy, including doxorubicin, is based on strong evidence. Most treatment recommendations for this unique population are based on expert opinion, not on empirical evidence.

RECENT FINDINGS

As patients with childhood cancers live longer, morbidity from the cardiac side effects of chemotherapy is increasing. Treatment-related cardiac damage is irreversible and often progressive. It is imperative that such damage be prevented with strategies such as limiting the cumulative anthracycline dose, the use of anthracycline structural analogues and the use of cardioprotective agents.

SUMMARY

A deeper understanding of the mechanisms of their cardiotoxicity reveals that there is no 'safe' dose of anthracyclines. However, certain risk factors, such as higher lifetime anthracycline cumulative doses, higher anthracycline dose rates, female sex, longer follow-up, younger age at anthracycline treatment and cardiac irradiation, are associated with more severe cardiotoxicity. We advocate the use of dexrazoxane to limit the cardiotoxic effects of anthracycline chemotherapy.

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.

The Safety of Ingested Caffeine: A Comprehensive Review

Caffeine is the most widely consumed psychoactive drug in the world. Natural sources of caffeine include coffee, tea, and chocolate. Synthetic caffeine is also added to products to promote arousal, alertness, energy, and elevated mood. Over the past decade, the introduction of new caffeine-containing food products, as well as changes in consumption patterns of the more traditional sources of caffeine, has increased scrutiny by health authorities and regulatory bodies about the overall consumption of caffeine and its potential cumulative effects on behavior and physiology. Of particular concern is the rate of caffeine intake among populations potentially vulnerable to the negative effects of caffeine consumption: pregnant and lactating women, children and adolescents, young adults, and people with underlying heart or other health conditions, such as mental illness. Here, we review the research into the safety and safe doses of ingested caffeine in healthy and in vulnerable populations. We report that, for healthy adults, caffeine consumption is relatively safe, but that for some vulnerable populations, caffeine consumption could be harmful, including impairments in cardiovascular function, sleep, and substance use. We also identified several gaps in the literature on which we based recommendations for the future of caffeine research.

Diagnosis and Diagnostic Modalities in Pediatric Patients with Elevated Troponin

Care of adults with coronary artery disease focuses on troponins to rapidly move patients to catheterization. Troponins are increasingly drawn in children, but emergent catheterization may not be indicted. We sought to establish etiologies of troponin elevation and ascertain the yield of diagnostic tests, in this population. Retrospective review of patients from January 1, 2002, to December 31, 2011, who had any elevated troponin during the study period. Patients were excluded for recent cardiac surgery, "significant" congenital heart disease, if they were neonates in the NICU or were on ECMO. Twenty-four patients made up our study group: 17/24 (71 %) had myocarditis or cardiomyopathy. Three had coronary-related diagnoses: 1 ALCAPA and 2 Kawasaki syndrome. The most useful testing for making or confirming the diagnoses included ECG, CXR and ECHO. Fourteen had right heart catheterization which was useful in 10/14. Nine had MRI which was useful in 7/9 (all five cases of suspected myocarditis). Left heart catheterization was completed in 10/24 cases, but in no case made or changed the diagnosis. This study confirms that children with elevated troponins differ from adults. The most common cause is myocarditis or cardiomyopathy, whereas coronary-related ischemia is rare. Diagnosis with ECG, CXR and ECHO is typically adequate. Focused use of right heart catheterization and MRI may be useful. In pediatric patients with elevated troponins, left heart catheterization and coronary angiography should be reserved for a highly selective group, and adult "door-to-balloon time" protocols should not be applied routinely.

Cardiac biomarkers in HIV-exposed uninfected children

OBJECTIVES

To evaluate associations of cardiac biomarkers with in-utero antiretroviral drug exposures and cardiac function/structure measured by echocardiograms in HIV-exposed but uninfected (HEU) children.

DESIGN AND METHODS

We analyzed the association of three cardiac biomarkers (cardiac troponin T, cTnT; high sensitivity C-reactive protein, hsCRP; and N-terminal pro-brain natriuretic peptide, NT-proBNP) with prenatal antiretroviral drug exposures, maternal-child characteristics, and echocardiographic parameters.

RESULTS

Among 338 HEU children (mean age 4.3 years), 51% had at least one elevated cardiac biomarker. Maternal tobacco use was associated with elevated NT-proBNP [adjusted odds ratio (aOR) 2.28, P=0.02]. Maternal alcohol and abacavir use were associated with elevated cTnT levels (aOR 3.56, P=0.01 and aOR 2.33, P=0.04, respectively). Among 94 children with paired echocardiogram-biomarker measurements, cTnT measurements were correlated with increased left-ventricular thickness-to-dimension ratio (r=0.21, P=0.04); and elevated cTnT was associated with higher mean left-ventricular end-diastolic (LVED) posterior wall thickness (P=0.04). hsCRP measurements were negatively correlated with septal thickness (r=-0.22, P=0.03) and elevated hsCRP was associated with lower mean left-ventricular contractility Z-scores (P=0.04). NT-proBNP measurements were correlated with increased LVED dimension (r=0.20, P=0.05) and elevated NT-proBNP was associated with lower mean end-systolic septal thickness (P=0.03).

CONCLUSION

Our findings suggest that cardiac biomarkers may help identify HEU children who require further cardiac evaluation including echocardiography. Potential cardiac effects of prenatal abacavir exposure in this population need further investigation.

Health effects of energy drinks on children, adolescents, and young adults

OBJECTIVE

To review the effects, adverse consequences, and extent of energy drink consumption among children, adolescents, and young adults.

METHODS

We searched PubMed and Google using "energy drink," "sports drink," "guarana," "caffeine," "taurine," "ADHD," "diabetes," "children," "adolescents," "insulin," "eating disorders," and "poison control center" to identify articles related to energy drinks. Manufacturer Web sites were reviewed for product information.

RESULTS

According to self-report surveys, energy drinks are consumed by 30% to 50% of adolescents and young adults. Frequently containing high and unregulated amounts of caffeine, these drinks have been reported in association with serious adverse effects, especially in children, adolescents, and young adults with seizures, diabetes, cardiac abnormalities, or mood and behavioral disorders or those who take certain medications. Of the 5448 US caffeine overdoses reported in 2007, 46% occurred in those younger than 19 years. Several countries and states have debated or restricted energy drink sales and advertising.

CONCLUSIONS

Energy drinks have no therapeutic benefit, and many ingredients are understudied and not regulated. The known and unknown pharmacology of agents included in such drinks, combined with reports of toxicity, raises concern for potentially serious adverse effects in association with energy drink use. In the short-term, pediatricians need to be aware of the possible effects of energy drinks in vulnerable populations and screen for consumption to educate families. Long-term research should aim to understand the effects in at-risk populations. Toxicity surveillance should be improved, and regulations of energy drink sales and consumption should be based on appropriate research.

Cardiovascular effects in childhood cancer survivors treated with anthracyclines

Anthracyclines are commonly used to treat childhood leukemias and lymphomas, as well as other malignancies, leading to a growing population of long-term childhood cancer survivors. However, their use is limited by cardiotoxicity, increasing survivors' vulnerability to treatment-related complications that can markedly affect their quality of life. Survivors are more likely to suffer from heart failure, coronary artery disease, and cerebrovascular accidents compared to the general population. The specific mechanisms of anthracycline cardiotoxicity are complex and remain unclear. Hence, determining the factors that may increase susceptibility to cardiotoxicity is of great importance, as is monitoring patients during and after treatment. Additionally, treatment and prevention options, such as limiting cumulative dosage, liposomal anthracyclines, and dexrazoxane, continue to be explored. Here, we review the cardiovascular complications associated with the use of anthracyclines in treating malignancies in children and discuss methods for preventing, screening, and treating such complications in childhood cancer survivors.

Cardiac troponin-I as a screening tool for myocarditis in children hospitalized for viral infection

AIM

The incidence of myocarditis in children is uncertain because patients with minor symptoms can remain undiagnosed. We hypothesized that screening all children who are hospitalized for an acute infection with troponin-I (TnI) would reveal myocarditis cases and performed a prospective screening study.

METHODS

Between October 2005 and July 2008, a blood sample for TnI measurement was taken every time a sample for C-reactive protein measurement was drawn. If TnI value was above the screening limit (0.06 microg/L), electrocardiogram (ECG) and cardiac ultrasound were performed. TnI measurements were repeated until at normal level.

RESULTS

Altogether, 1009 children were screened during the 33 months. TnI was above the screening limit (0.06 microg/L) in six children. None of them had any signs of myocarditis in ECG or cardiac ultrasound. Five of those six children were younger than 30 days. All had a respiratory infection as a cause for hospitalization, three of which was caused by RSV. In four children, all younger than 30 days, TnI levels remained high (>0.37 microg/L) for two months, but decreased after that to normal levels.

CONCLUSION

The incidence of myocarditis during viral infections is low and a routine TnI screening for asymptomatic myocarditis is not useful.

Frequency of elevations in markers of cardiomyocyte damage in otherwise healthy newborns

Myocardial damage in infancy is a risk factor for eventual cardiac disease. Given that myocardial stress is greatest during the perinatal period and that the neonatal period is when most pediatric heart failure occurs, the aim of this study was to determine whether even otherwise healthy neonates might have subclinical myocardial damage and, if so, what characteristics might identify them. Umbilical cord and neonatal serum samples from 32 normal neonates were assayed for biomarkers of myocardial injury. No neonate had clinical evidence of cardiac or other abnormalities. Serum cardiac troponin T was elevated in 19 of 25 cords (76%) and in 16 of 17 neonates (94%); levels indicating myocardial infarction (> or =0.2 ng/ml) were found in 2 patients (1 umbilical cord and 1 neonatal sample). Creatine kinase-MB was elevated in 6 of 16 cords (38%) and in 8 of 15 neonates (53%). Cardiac troponin I was elevated in 11% and 17% of samples, myoglobin in 4% and 17%, and high-sensitivity C-reactive protein in 9% and 40%. Measures of myocardial injury were associated with longer hospitalization (r = 0.50, p = 0.04), non-Caucasian race (p = 0.012), lower birth weights (p = 0.014), positive maternal cervical cultures (r = 0.41, p = 0.046), and elevated high-sensitivity C-reactive protein (r = 0.66, p = 0.005). In conclusion, clinically occult myocardial injury appears to occur in some healthy newborns, although whether it is pathologic or not remains to be determined.