Duy T. Dao

Outcomes of Children Following a First Hospitalization for Dilated Cardiomyopathy

Background—We hypothesized that children with dilated cardiomyopathy who require hospital admission are at increased risk for death or transplantation during their first hospitalization and in the first year that follows. We also assessed the value of routine data collected during that time to predict death or the need for transplantation prior to discharge and within 1 year of admission. Methods and Results—We conducted a retrospective review of 83 pediatric patients with dilated cardiomyopathy whose initial hospitalization fell between 2004 and 2009. The mean age at hospitalization was 7 years. The majority of patients demonstrated moderate or severe left ventricular dysfunction on initial echocardiogram (80%) and/or the need for intravenous inotropes within 7 days of hospital admission (69%). Five patients (6%) died, and 15 (18%) were transplanted in the initial hospitalization. At 1 year, 11/71 (15%) had died, and 27/71 (38%) were transplanted. The overall freedom from death, transplantation, or rehospitalization at 1 year following admission was 21%. Fractional shortening, left ventricular ejection fraction, serum cholesterol, uric acid, mixed venous saturation, and atrial filling pressures were all predictive of death or transplantation during the initial hospitalization. Left ventricular ejection fraction was predictive of death or transplantation at 1 year. Conclusions—The first hospitalization for dilated cardiomyopathy marks a period of high risk for clinical decline, end stage heart failure, and the need for cardiac transplantation. Echocardiographic function and hemodynamic and serum measurements may aid in predicting outcomes. Despite medical management, most patients will be rehospitalized and/or require cardiac transplantation within 1 year of admission.

Ventricular assist devices in a contemporary pediatric cohort: Morbidity, functional recovery, and survival

BACKGROUND Limited availability of donor organs has led to the use of ventricular assist devices (VADs) to treat heart failure in pediatric patients, primarily as bridge to transplantation. How effective VAD therapy is in promoting functional recovery in children is currently not known. METHODS We report morbidity and mortality as defined by the Interagency Registry for Mechanically Assisted Circulatory Support Modified for Pediatrics (PediMACS) and the use of the Treatment Intensity Score to assess functional status for 50 VAD patients supported at a single pediatric program from 2004 to 2013. RESULTS In this cohort, 30-day survival on VAD was 98%, and 180-day survival was 83%. Stroke occurred in 11 patients (22%), with 8 (16%) resulting in persistent neurologic deficit or death. The adverse event rate was 2-fold to 3-fold higher in the first 7 days of support compared with the subsequent support period. Functional status, as measured by the Treatment Intensity Score, improved with duration of support. Successful bridge to transplantation was associated with fewer adverse events during support and greater improvement in the Treatment Intensity Score during the period of support. CONCLUSIONS Overall survival in this cohort is excellent. The risk of serious adverse events decreases over the first month of support. However, a clinically significant risk of morbidity and mortality persists for the duration of pediatric VAD support. Measures of functional status improve with duration of support and are associated with survival to transplantation.

Intravenous Fat Emulsion Formulations for the Adult and Pediatric Patient Understanding the Differences

Intravenous fat emulsions (IVFEs) provide essential fatty acids (EFAs) and are a dense source of energy in parenteral nutrition (PN). Parenterally administered lipid was introduced in the 17th century but plagued with side effects. The formulation of IVFEs later on made it a relatively safe component for administration to patients. Many ingredients are common to all IVFEs, yet the oil source(s) and its (their) percentage(s) makes them different from each other. The oil used dictates how IVFEs are metabolized and cleared from the body. The fatty acids (FAs) present in each type of oil provide unique beneficial and detrimental properties. This review provides an overview of IVFEs and discusses factors that would help clinicians choose the optimal product for their patients.

Extracorporeal membrane oxygenation in children with heart disease and genetic syndromes.

Our objective was to evaluate morbidity and mortality associated with extracorporeal membrane oxygenation (ECMO) in children with genetic syndromes and heart disease. We conducted a retrospective review of all children with heart disease and genetic syndromes receiving ECMO during the period January 2000 and March 2012 at Arkansas Children’s Hospital, Little Rock. The medical charts were reviewed to obtain the following variables: demographic information, medical and surgical history, laboratory and microbiological, information on organ dysfunction, and outcome characteristics. The outcome variables evaluated in this report included: hospital length of stay (LOS), survival to hospital discharge, and current survival. Outcome data were compared among critically ill children with and without syndromes. During the study period, there were 377 ECMO runs in 336 children with heart disease. Of these, 43 ECMO runs occurred in children with genetic syndromes whereas 334 ECMO runs occurred in children with no genetic abnormality. Children in the group with underlying genetic syndrome were older at the time of ECMO cannulation than the group with no syndrome. During the ECMO run, hospital LOS and mortality were similar in children with and without underlying genetic abnormality. Among genetically abnormal patients, renal insufficiency and need for dialysis were associated with mortality. In this group, 24 patients (56%) were discharged alive. However, only 10 patients are living to date in this cohort. ECMO can be used in children with heart disease and genetic syndromes with good results. The survival rate is high and the complication rate is low.

Variability of characteristics and outcomes following cardiopulmonary resuscitation events in diverse ICU settings in a single, tertiary care children's hospital*.

Objective: The primary objective of this study was to compare and contrast the characteristics and survival outcomes of cardiopulmonary resuscitation for “monitored” events in pediatric patients treated with chest compressions more than or equal to 1 minute in varied ICU settings. Design: Retrospective observational study. Setting: Three different specialized ICUs in a single, tertiary care, academic children’s hospital. Patients: We collected demographic information, preexisting conditions, preevent characteristics, event characteristics, and outcome data. The primary outcome measure was survival to hospital discharge. Secondary outcome measures included return of spontaneous circulation, 24-hour survival, and survival with good neurologic outcome. Interventions: None. Measurements and Main Results: Four hundred eleven patients treated with chest compressions for more than or equal to 1 minute were included in the analysis: 170 patients were located in the cardiovascular ICU, 157 patients in the neonatal ICU, and 84 patients in the PICU. Arrest durations were longer in the cardiovascular ICU than other ICUs. Use of extracorporeal cardiopulmonary resuscitation was more prevalent in the cardiovascular ICU (cardiovascular ICU, 17%; neonatal ICU, 3%; PICU, 4%). Return of spontaneous circulation, 24-hour survival, survival to hospital discharge, and good neurologic outcome were highest among neonatal ICU patients (survival to discharge, 53%) followed by cardiovascular ICU patients (survival to discharge, 46%) and PICU patients (survival to discharge, 36%). In a multivariable model controlling for patient and event characteristics, using cardiovascular ICU as reference, adjusted odds of survival in PICU were 0.33 (95% CI, 0.14–0.76; p = 0.009) and odds of survival in neonatal ICU were 0.80 (95% CI, 0.31–2.11; p = 0.65). Conclusions: Comparative analysis of pediatric patients undergoing cardiopulmonary resuscitation in three different ICU settings demonstrated a significant variation in baseline, preevent, and event characteristics. Although outcomes vary significantly among the three different ICUs, it was difficult to ascertain if this difference was due to variation in the disease process or variation in the location of the patient.

Redefining essential fatty acids in the era of novel intravenous lipid emulsions

The essentiality of fatty acids was determined by the Burrs in the 1920s. It is commonly accepted that provision of linoleic (LA) and alpha-linolenic acids (ALA) prevents and reverses essential fatty acid deficiency (EFAD). Development of alternative injectable lipid emulsions (ILE) low in LA and ALA has raised concern about their ability to prevent EFAD. This review provides biochemical evidence coupled with observations from animal and human studies that aim to characterize which fatty acids are truly essential to prevent EFAD. Retroconversion pathways and mobilization from body stores suggest that arachidonic and docosahexaenoic acids (ARA and DHA - the main derivatives of LA and ALA, respectively) also prevent EFAD. Our group first proposed the essentiality of ARA and DHA by feeding mice exclusively these fatty acids and proving that they prevent EFAD. Survival for 5 generations on this diet provides additional evidence that growth and reproductive capabilities are maintained. Moreover, the use of fish oil-based ILE, with minimal LA and ALA and abundant DHA and ARA, for treatment of intestinal failure-associated liver disease, does not result in EFAD. These findings challenge the essentiality of LA and ALA in the presence of ARA and DHA. Evidence discussed in this review supports the idea that ARA and DHA can independently fulfill dietary essential fatty acid requirements. The imminent introduction of new ILE rich in ARA and DHA in the United States highlights the importance of understanding their essentiality, especially when provision of ALA and LA is below the established daily minimum requirement.

Predictors of failure of fish-oil therapy for intestinal failure–associated liver disease in children

BACKGROUND Parenteral fish-oil (FO) therapy is a safe and effective treatment for intestinal failure-associated liver disease (IFALD). Patients whose cholestasis does not resolve with FO may progress to end-stage liver disease. OBJECTIVE We sought to identify factors associated with the failure of FO therapy in treating IFALD to guide prognostication and referral guidelines. DESIGN Prospectively collected data for patients treated with FO at Boston Childrens Hospital from 2004 to 2014 were retrospectively reviewed. Resolution of cholestasis was defined as sustained direct bilirubin (DB) <2 mg/dL, and treatment failure as liver transplantation or death while DB was >2 mg/dL as of July 2015. Demographics, laboratory values, and medical history at FO therapy initiation were compared between patients who achieved resolution of cholestasis and those who failed therapy. RESULTS Among 182 patients treated with FO, 86% achieved resolution of cholestasis and 14% failed therapy. Patients who failed therapy had median (IQR) lower birth weight [1020 g (737, 1776 g) compared with 1608 g (815, 2438 g); P = 0.03] and were older at FO initiation [20.4 wk (9.9, 38.6 wk) compared with 11.7 wk (7.3, 21.4 wk); P = 0.02] than patients whose cholestasis resolved. Patients who failed therapy had more advanced liver disease at therapy initiation than patients whose cholestasis resolved, as evidenced by lower median (IQR) γ-glutamyltransferase [54 U/L (41, 103 U/L) compared with 112 U/L (76, 168 U/L); P < 0.001], higher DB [10.4 mg/dL (7.5, 14.1 mg/dL) compared with 4.4 mg/dL (3.1, 6.6 mg/dL); P < 0.001], and a higher pediatric end-stage liver disease (PELD) score [22 (14, 25) compared with 12 (7, 15); P < 0.001]. A PELD score of ≥15, history of gastrointestinal bleeding, age at FO initiation ≥16 wk, presence of nongastrointestinal comorbidities, and mechanical ventilation at FO initiation were independent predictors of treatment failure. CONCLUSIONS Most infants with IFALD responded to FO therapy with resolution of cholestasis, and liver transplantation was rarely required. Early FO initiation once biochemical cholestasis is detected in parenteral nutrition-dependent patients is recommended. This trial was registered at clinicaltrials.gov as NCT00910104.

QRS prolongation is strongly associated with life-threatening ventricular arrhythmias in children with dilated cardiomyopathy

BACKGROUND The incidence of sudden death in children with dilated cardiomyopathy has been estimated at < 1% annually. This number, however, may underestimate the incidence of life-threatening arrhythmias. The objective of this study was to assess the incidence of and identify risk factors for life-threatening arrhythmias in children with dilated cardiomyopathy. METHODS We conducted a retrospective record review of 183 children with dilated cardiomyopathy treated at a single center between 2000 and 2011. Life-threatening arrhythmia was defined as any ventricular arrhythmia that resulted in syncope or hypotension and required medical intervention. Risk factors for life-threatening arrhythmias were identified with univariate analyses. A prediction model was constructed with multivariate logistic regression and receiver operating characteristic curves. RESULTS Nineteen patients experienced life-threatening arrhythmias, representing an annualized rate of 4.9%. Outpatient life-threatening arrhythmias occurred at a rate of 2.2% per year. Predictors of outpatient life-threatening arrhythmias were longer QRS duration (p = 0.003) and increased left ventricular posterior wall (LVPWd) thickness (p = 0.03). Only QRS duration remained significant in multivariate logistic regression (odds ratio, 1.8 for every unit increase in z-score; 95% CI, 1.01-1.9; p = 0.04). For all life-threatening arrhythmias, prolonged QRS duration was the only significant risk factor in multivariate logistic regression (odds ratio, 1.5; 95% CI, 1.1-2.2; p = 0.02). CONCLUSION In children with dilated cardiomyopathy, as QRS duration increases, so too does the risk of life-threatening arrhythmias. Life-threatening arrhythmias occurred at an annual rate of 5%, which was much higher than the previously reported rate of sudden cardiac death in this population.

A Comparison of Fish Oil Sources for Parenteral Lipid Emulsions in a Murine Model

Background: Fat emulsions are important components of parenteral nutrition (PN). Fish oil (FO) emulsions reverse cholestasis in PN-associated liver disease. There are 2 FO monographs. One is “FO; rich in omega-3 fatty acids” (NFO). The other, “omega-3 acids,” (PFO), is enriched in omega-3 fatty acids, particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The purpose of this study is to compare the effects of 20% NFO and PFO emulsions produced in the laboratory in a murine model. Methods: Emulsions were compounded containing different oils: soybean oil (SO), NFO, and two PFOs differing in percentage of fatty acids as triglycerides (PFO66 and PFO90). Chow-fed mice received saline, one of the above emulsions, or a commercial FO (OM) intravenously (2.4 g/kg/day) for 19 days. On day 19, animals were euthanized. Livers, spleens, and lungs were procured for histologic analysis. Results: OM, SO, NFO, and PFO90 were well-tolerated clinically. PFO66 resulted in tachypnea and lethargy for ~1 minute following injections. At euthanasia, PFO66 and PFO90 groups had organomegaly. Histologically, these groups had splenic and hepatic fat-laden macrophages, and lungs had scattered fat deposits. Other groups had normal organs. Conclusions: PFO emulsions present an attractive possibility for improving inflammation in PN-dependent patients by concentrating anti-inflammatory EPA and DHA. However, 20% PFO emulsions were poorly tolerated and precipitated adverse end organ sequelae, suggesting that they may not be safe. Development of novel manufacturing methods may achieve safe 20% PFO parenteral emulsions, but by established formulation methods, these emulsions were clinically suboptimal despite meeting pharmacopeial standards.

Electrocardiographic repolarization abnormalities and increased risk of life-threatening arrhythmias in children with dilated cardiomyopathy

BACKGROUND Life-threatening arrhythmia events (LTEs) occur in ~5% of children with dilated cardiomyopathy (DCM). While prolonged QRS duration has been shown to be associated with LTEs, electrocardiographic (ECG) repolarization findings have not been examined. OBJECTIVE We sought to determine the associations between ECG repolarization abnormalities and LTEs in children with DCM. METHODS A single-center retrospective review of children with DCM was performed. LTEs were defined as documented ventricular tachycardia or fibrillation requiring medical intervention. Three pediatric cardiologists, blinded to clinical events, evaluated ECGs obtained at the time of initial referral. Kaplan-Meier survival and Cox proportional hazards analyses were used to evaluate time to LTEs. RESULTS A total of 137 patients (mean age 7.8 ± 6.7 years; 75(55%) male patients) with DCM (mean ejection fraction 35% ± 16%) were included; 67 patients (49%) had a corrected JT (JTc) interval of ≥340 ms, 72 (53%) had a corrected QT (QTc) interval of ≥450 ms, and 41 (30%) had abnormal T waves. LTEs occurred in 15 patients at a median of 12 months (interquartile range 3-36 months) after the initial ECG. Patients with LTEs had a longer JTc interval (371 ± 77 ms vs 342 ± 41 ms; P = .02) and a longer QTc interval (488 ± 96 ms vs 453 ± 44 ms; P = .01). In survival analysis, a JTc interval of ≥390 ms (hazard ratio [HR] 4.07; 95% confidence interval [CI] 1.12-14.83; P = .03), a QTc interval of ≥510 ms (HR 6.95; 95% CI 1.53-31.49; P = .01), abnormal T-wave inversion (HR 11.62; 95% CI 2.75-49.00; P = .001), and ST-segment depression (HR 6.91; 95% CI 1.25-38.27; P = .03) were associated with an increased risk of LTEs, even after adjusting for QRS duration and amiodarone use. CONCLUSION Repolarization abnormalities are common in children with DCM. Certain ECG repolarization abnormalities, such as significantly prolonged JTc and QTc intervals, may be useful in identifying patients at risk of LTEs.