Stress perfusion magnetic resonance imaging to detect coronary artery lesions in children.

BACKGROUND: Stress perfusion cardiovascular magnetic resonance (CMR) is used widely in adult ischemic heart disease, but data in children is limited. We sought to evaluate feasibility, accuracy and prognostic value of stress CMR in children with suspected coronary artery disease (CAD). METHODS: Stress CMR was reviewed from two pediatric centers over 5 years using a standard pharmacologic protocol. Wall motion abnormalities, perfusion deficits and late enhancement were correlated with coronary angiogram (CAG) when available, and clinical status at 1 year follow-up for major adverse cardiovascular events (MACE; coronary revascularization, non-fatal myocardial infarction and death due to CAD) was recorded. RESULTS: Sixty-four stress perfusion CMR studies in 48 children (10.9 ± 4.8 years) using adenosine; 59 (92%) and dipyridamole; 5 (8%), were reviewed. Indications were Kawasaki disease (39%), post arterial switch operation (12.5%), post heart transplantation (12.5%), post anomalous coronary artery repair (11%), chest pain (11%), suspected myocarditis or CAD (3%), post coronary revascularization (3%), and others (8%). Twenty-six studies were performed under sedation. Of all studies performed, 66% showed no evidence of ischemia or infarction, 28% had perfusion deficits and 6% had late gadolinium enhancement (LGE) without perfusion deficit. Compared to CAG, the positive predictive value (PPV) of stress CMR was 80% with negative predictive value (NPV) of 88%. At 1 year clinical follow-up, the PPV and NPV of stress CMR to predict MACE were 78 and 98%. CONCLUSION: Stress-perfusion CMR, in combination with LGE and wall motion-analysis is a feasible and an accurate method of diagnosing CAD in children. In difficult cases, it also helps guide clinical intervention by complementing conventional CAG with functional information.

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.

Dexamethasone given to premature infants and cardiac diastolic function in early childhood.

OBJECTIVES: To determine if dexamethasone given to premature infants with bronchopulmonary dysplasia would result in cardiac diastolic dysfunction in early childhood, a topic unstudied in humans. STUDY DESIGN: We compared seven children ages 3 to 8 years born at 26 weeks' gestation and given dexamethasone for bronchopulmonary dysplasia with eight gestation-matched and age-matched control children using echocardiography to assess measures of systolic and diastolic function. All dexamethasone patients had resolved hypertrophic cardiomyopathy. RESULTS: Dexamethasone patients had the same normal τ and isovolumic relaxation time (24.9 ± 2.8 and 54.6 ± 6.3 ms) as control patients (22.1 ± 3.0 and 48.8 ± 6.7 ms). Peak A velocities were the same in dexamethasone patients as in control patients (59.5 ± 15 versus 49.4 ± 5.8 cm/s, P = .10), resulting in unchanged E:A ratios (1.89 ± 0.57 versus 2.15 ± 0.43, P = .22). Peak E velocity and E-wave deceleration times were not different. We found no significant differences in measures of systolic function (heart rate-corrected velocity of circumferential fiber shortening, wall stress, and ejection fraction). Left ventricular mass was the same between the groups confirming resolution of hypertrophic cardiomyopathy. CONCLUSIONS: These data are consistent with normal myocardial relaxation, suggesting that long-term diastolic function is reassuringly normal in children who received dexamethasone as premature infants with resolution of hypertrophic cardiomyopathy.

Repeated systematic surveillance of Kawasaki disease in Ontario from 1995 to 2006.

BACKGROUND: Rising incidences of Kawasaki disease (KD) have been reported worldwide. Reported herein are the results of 4 triennial KD surveillances conducted in Ontario. METHODS: Between 1995 and 2006 all hospitals in Ontario were asked on 4 occasions to identify all patients with discharge diagnoses of KD and report incident cases. RESULTS: The latest surveillance identified 697 new KD patients (100% response rate) for a total of 2378 KD patients through all 4 surveillances. Yearly incidence was 26.2/100,000 for <5 years old, 6.7/100,000 for 5-9 years old and 0.9/100,000 for 10-14 years old. KD incidence significantly increased from 1995 to 2006, although the increase seemed to plateau between the 3rd and 4th surveillance. There was an increase in the proportion of patients diagnosed with incomplete KD and a significant reduction in the rate of coronary artery abnormalities, possibly due to better disease recognition and treatment. Hospitals reporting <20 cases per surveillance were found to be more likely to report cases with incomplete KD. These patients were also less likely to be treated with i.v. immunoglobulin and aspirin but were more likely to be treated with antibiotics, suggesting uncertainties regarding diagnosis and management of KD patients in those centers. CONCLUSIONS: The incidence of KD in Ontario is possibly one of the highest outside of Asia and has been rising since 1995. Although the most recent surveillance demonstrated improved cardiac outcomes, treatment delays or absence thereof continue to be a problem. Effective diagnosis and prompt treatment remain critical aspects of KD management.

Should prevention of chronic kidney disease start before pregnancy?

OBJECTIVE: The objective was to evaluate whether there is a role for the prevention of future chronic kidney disease (CKD) in children by improving maternal health at conception, this review addresses: the risk of childhood obesity in the development of CKD, trends in childhood obesity and body composition in children with renal diseases, trends in pre-pregnancy BMI and its association with neonatal outcome, and the effect of pre-pregnancy body mass index (BMI) on blood pressure and body composition in the offspring. INCREASED BMI AND HYPERTENSION AS RISK FACTORS FOR CKD: It is now well established that the presence of hypertension increases the risk of CKD. Increased BMI can also increase the risk of the development of CKD indirectly, through an increase in the prevalence of hypertension, and, possibly, through a direct effect independent of hypertension. TRENDS IN CHILDHOOD OBESITY IN GENERAL, AND SPECIFICALLY AMONG CHILDREN WITH RENAL DISEASES: An unprecedented epidemic of childhood obesity has been witnessed since the 1970s. An estimated 35% of children in North America are reported to be overweight. Children with CKD have even higher BMIs. TRENDS IN PRE-PREGNANCY BMI AND ITS ASSOCIATION WITH NEONATAL OUTCOME: The average BMI of mothers delivering in a single hospital in London, Ontario, rose from 24.3 kg/m2 in 1995 to 25.1 kg/m2 in 2004, whereas the average age of conception of the first child remained unchanged at 28 years. High pre-pregnancy BMIs increased the proportion of large-for-gestational-age newborns, a high proportion of congenital anomalies including renal abnormalities, and the need for Cesarean sections. EFFECT OF PRE-PREGNANCY BMI ON BLOOD PRESSURE AND BODY COMPOSITION IN THE OFFSPRING: Among 1,915 children (mean age 8.3 +/- 5.2 years), studied at the Children's Hospital, London Health Science Centre, BMI z-score correlated significantly with systolic (Spearman r = 0.214, P < 0.0001), and diastolic blood pressure z-scores (Spearman r = 0.143, P < 0.0001). The pre-pregnancy BMI correlated with both BMI z-score (Spearman r = 0.144, P < 0.0001) and blood pressure z-score (Spearman r = 0.13, P = 0.0005) in the children. The birth weight also correlated significantly with a higher BMI z-score (Spearman r = 0.134, P < 0.0001). CONCLUSION: There are increasing trends in childhood obesity and pre-pregnancy maternal BMI. Higher pre-pregnancy BMI increases the risk for increased BMI z-score and blood pressure z-score in children. Since elevated BMI and blood pressure clearly are known risk factors of future CKD, targeting healthier weights prior to conception is likely to reduce the CKD burden in children.

Enoxaparin use in the neonatal intensive care unit: experience over 8 years.

STUDY OBJECTIVE: To evaluate the effectiveness and safety of enoxaparin therapy in a neonatal intensive care unit (NICU). DESIGN: Retrospective chart review. SETTING: Level III NICU in a Canadian academic center. PATIENTS: All neonates treated with enoxaparin while in the NICU between January 1, 1998, and June 1, 2006. MEASUREMENTS AND MAIN RESULTS: Data abstracted included patient demographics, diagnosis of thrombosis and its progression, enoxaparin dosages with corresponding antifactor Xa levels, and adverse events. Sixteen neonates (four term, 12 preterm) were treated with enoxaparin at a mean +/- SD initial subcutaneous dose of 1.41 +/- 0.15 mg/kg every 12 hours. The target therapeutic range (antifactor Xa level 0.5-1.0 U/ml) was achieved by 12 infants at a mean +/- SD dose of 1.92 +/- 0.43 mg/kg every 12 hours, after a mean of 5.6 days (range 1-15 days). Preterm infants required a higher dose (per kilogram) compared with term infants to maintain therapeutic antifactor Xa levels (mean +/- SD 1.94 +/- 0.39 vs 1.65 +/- 0.14 mg/kg every 12 hrs, p<0.001). Enoxaparin doses were more strongly correlated to antifactor Xa levels in term infants (r(2)=0.51, p<0.001) compared with preterm infants (r(2)=0.20, p<0.001). Ten (71%) of 14 thromboembolic events resolved, either partially or completely, at a mean of 39 days (range 8-61 days) of enoxaparin therapy. Nine infants (56%) experienced minor local adverse effects at the site of the indwelling subcutaneous catheter (induration, bruises, hematomas, or leakage). Systemic adverse events that were possibly related to enoxaparin therapy included osteopenia (one infant), scleral hemorrhage (one), and minor gastrointestinal tract bleeding (three) found in gastric feeding tubes. No adverse effects were associated with antifactor Xa levels greater than 1.0 U/ml. CONCLUSION: Enoxaparin may be effective in the treatment of neonatal thrombosis. An initial dosage of 1.5 mg/kg every 12 hours is likely inadequate to obtain therapeutic antifactor Xa levels rapidly and differs for term and preterm neonates. Therapeutic levels in preterm infants may be more variable, and the pharmacokinetics of this drug in preterm infants requires further evaluation. Future studies in neonates should prospectively evaluate a higher starting dose of enoxaparin to document effectiveness, acceptance, compliance with treatment guidelines, and adverse effects.

Accelerated ventricular rhythm in healthy neonates.

Accelerated ventricular rhythm is similar in rate to the original sinus rhythm. Although 19 cases have been reported in healthy neonates without congenital disease, it is seen with some regularity at tertiary care paediatric cardiac centres. Accelerated ventricular rhythm carries good prognosis, but it is frequently misdiagnosed as ventricular tachycardia and is, thus, unnecessarily treated. The present report describes a case of a neonate who was not properly diagnosed after birth and who was inappropriately treated.