Physician-researchers from the Cardiac Center at Children's Hospital of Philadelphia (CHOP) presented new findings on pediatric cardiovascular disease at the American College of Cardiology's 67th Annual Scientific Session & Expo 2018 in Orlando, Fla. Among many abstracts presented were emergency department visits in patients with congenital heart disease, social risk factors for readmission, factors predicting mortality after prolonged critical illness and more.
Modifiable Factors Predict Mortality After Prolonged Critical Illness Following Congenital Heart Surgery
Patients who suffer prolonged critical illness (PCI) after congenital heart surgery are at high risk for mortality, yet the extent to which mortality after critical illness is preventable remains unknown. The researchers aimed to determine the modifiable and non-modifiable factors predicting mortality for patients with PCI after heart surgery at hospitals in the Pediatric Cardiac Critical Care Consortium (PC4). The team performed an observational analysis of the PC4 clinical registry of all admissions to the cardiac intensive care unit (CICU) after congenital heart surgery from August 2014 to December 2016, stratified into neonates (under 28 days) and non-neonates, and defined PCI as length of stay greater than the 90th percentile. The primary outcome was death prior to discharge from CICU. Of the 13,106 surgical episodes from 23 hospitals, the final cohort was 242 neonates and 1,184 non-neonates with PCI. Of these, 57 (24 percent) neonates and 92 (8 percent) non-neonates died in the CICU. Mechanical ventilation days, cardiac arrest, renal replacement therapy and unplanned re-operation independently predicted mortality in both groups. Time to freedom of vasoactives predicted mortality in neonates, while nitric oxide use, pre-operative comorbidities and mechanical circulatory support predicted mortality in non-neonates. Prematurity, extra-cardiac and chromosomal abnormalities, and surgical complexity were not associated with mortality in either cohort. Complications and prolonged critical care therapy drive mortality after PCI more than innate patient characteristics, particularly in neonates. Aaron Dewitt et al. "Modifiable Factors Predict Mortality After Prolonged Critical Illness Following Congenital Heart Surgery" presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018. This abstract was selected as the Best Poster.
Smaller aortic isthmus size is associated with earlier surgical timing in complete common atrioventricular canal defects
Complete common atrioventricular canal (CAVC) heart defects are common, but data is limited regarding the relationship between patient-specific pre-operative characteristics and operative timing. The research team performed a retrospective, single-center review of all patients who underwent primary biventricular repair for complete CAVC defects between 2006 and 2015. Surgeons performed complete CAVC repair in 153 subjects at a mean age of 102 days. Aortic isthmus z-score on initial echocardiogram, pre-operative admission for heart failure, need for supplemental nutrition and lower birth weight were associated with earlier surgical repair. Evaluating early versus late repair, only aortic isthmus dimension was significant. Down syndrome, prematurity, use of diuretics, pre-operative atrioventricular valve regurgitation and aortic annulus size were not associated with surgical timing. Smaller aortic isthmus size, even without coarctation, is an important predictor of earlier surgical repair in complete CAVC. Although the timing of repair of CAVC is dependent on many factors, the relationship between aortic isthmus z-score and timing of surgery suggests that this measurement may be useful for providers in their initial counseling of families with regard to surgical timing. Danielle Burstein et al. "Smaller aortic isthmus size is associated with earlier surgical timing in complete common atrioventricular canal defects," presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018.
Emergency Department Visits Among Children with Congenital Heart Disease in the US
Children with congenital heart disease (CHD) presenting to the Emergency Department (ED) represent a medically complex population at increased risk for morbidity, mortality and resource utilization compared to those without CHD. The research team performed an analysis of data from the Nationwide Emergency Department Sample for 2006 to 2014. Patients age up to and including 18 years old with CHD were placed in one of three categories: simple CHD (atrial septal defect, ventricular septal defect, patent ductus arteriosus, atrioventricular canal defect); single ventricle; and other complex CHD. During the study time period, there were 41,196-48,501 annual CHD-related ED visits. Compared with non-CHD visits, those with CHD were more likely to be under one year of age, in an urban environment, in a teaching hospital and to pay with Medicaid. The most common presenting complaint was acute respiratory disease. More than 35 percent of CHD patients presenting to the ED had one or more complex chronic condition. Those with CHD were more likely to be admitted, and had higher median ED charges. Mortality was higher for CHD patients. Over nine years, there was an increase in median ED charge, while the mortality rate for CHD ED presentations decreased. This study better elucidates the number of CHD patients seen in the ED, details their medical complexity, examines risk factors for presentation to the ED and inpatient admission over time and describes temporal trends with respect to cost and mortality. Jonathan B. Edelson et al. "Emergency Department Visits Among Children with Congenital Heart Disease in the United States from 2006 to 2014," presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018
Predictive Model Identifies Patients Under Age One with a High Risk of Developing Hospital-Acquired Thrombosis
Hospital-acquired venous thrombosis (HAT) in children with congenital and acquired heart disease may be life-threatening. Children under age one are at highest risk and strategies to prevent HAT are lacking. The researchers performed a cohort study to develop a risk prediction model for HAT in babies by examining all admissions to the Cardiac Center at CHOP from September 2013 through December 2016 in infants less than one year of age during which a new HAT developed. Controls included all admissions without thrombosis in patients under one year of age for the same time period. Of the 1995 admissions, HAT developed in 83. Patients with prior thrombosis, younger age, chylothorax, single ventricle physiology, cardiac surgery, sepsis, central venous catheter and femoral catheter site were at highest risk. From this data, a risk prediction model was created with greater than 50 percent sensitivity and 97 percent specificity. Of patients identified by the model, over 50 percent went on to develop HAT. This model will inform further studies using prophylaxis with anticoagulants in infants with high risk of HAT. Therese M. Giglia, Leslie Raffini, et al. "Predictive Model for Hospital-Acquired Thrombosis in Pediatric Cardiac Patients Under One Year of Age," presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018.
Social Risk Factors Impact Hospital Readmission for Children with Congenital Heart Disease
Prolonged hospitalization and readmission for children with congenital heart disease (CHD) can increase risk for infection, impede development and increase costs. Social determinants of hospitalization and readmission are known for adult cardiac patients, but not for children with CHD, who are particularly vulnerable to the developmental impacts of hospitalization. The researchers examined records for 219 patients who underwent infant cardiac surgery with cardiopulmonary bypass. Cumulative social risk (racial/ethnic minority, Medicaid insurance, non-English speaking, maternal age at birth, regional socioeconomic status, distance from an outpatient cardiology clinic) was divided into high social risk vs low social risk, and risk of morbidity by procedure was ranked. Social risk groups did not differ on presence of genetic syndrome or single ventricle physiology. Interactions between social risk and morbidity score were identified for number of readmissions to age one and readmission days to age two. Comparisons showed that at low morbidity scores, patients with high social risk had more readmissions and greater number of readmission days than those at low social risk. High social risk also predicted significantly worse adherence to cardiology appointments and lower developmental scores. Social risk factors impact readmission rates and days for CHD patients with low risk of morbidity by procedure. Abby Demianczyk, et al. "Social Risk Factors Impact Hospital Readmission for Children with Congenital Heart Disease," presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018.
Chronotropic Response Predicts Exercise Performance in Children and Adolescents with Repaired Tetralogy of Fallot
The determinants of exercise performance in tetralogy of Fallot (TOF) are not well understood. The research team retrospectively analyzed a cross-sectional cohort of patients with TOF and evaluated the association of heart rate reserve with measures of exercise performance in a cohort of 152 patients with TOF, ages 8 to 18 years, who were studied prospectively by cardiac magnetic resonance and exercise stress test. The analysis showed that greater heart rate reserve was associated with better percent-predicted maximum oxygen consumption (%mVO2) and percent-predicted maximum work. This association remained significant after adjusting for indexed right ventricle end diastolic volume and left ventricular stroke volume. In the analysis of subjects that achieved a maximal effort on exercise testing, the only significant predictor of %mVO2 was left ventricular stroke volume. Heart rate reserve is an important contributor to exercise performance in patients with TOF during submaximal exercise, independent of right ventricle volume. Shivani M. Bhatt, et al. "Chronotropic Response Predicts Exercise Performance in Children and Adolescents with Repaired Tetralogy of Fallot," presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018.
Comparing Resource Utilization Among Pediatric Heart Transplant Indications Using a Novel, Merged Data Set
The recent UNOS-PHIS database merger enables novel analyses of inpatient management for pediatric heart transplant recipients. This study evaluated the variation in resource utilization among differing transplant indications using UNOS-PHIS data. The research team retrospectively analyzed a merged UNOS-PHIS cohort of pediatric heart transplant recipients from participating centers between 2004 and 2015. Patients were categorized as congenital heart disease (CHD), myocarditis and cardiomyopathy based on the UNOS-defined primary indication for first heart transplant. Of 2,264 pediatric heart transplants (1,106 CHD, 106 myocarditis, 1,039 cardiomyopathy), CHD recipients were younger and less likely to have a ventricular assist device at the time of transplant. Most transplants (86 percent) occurred at centers performing more than 10 pediatric heart transplants annually. Post-transplant length of stay, ICU resource utilization and mechanical ventilation were all longer in CHD than myocarditis or cardiomyopathy. Post-transplant costs were higher for CHD compared to myocarditis and cardiomyopathy, primarily driven by longer length of stay. Congenital heart disease is associated with increased resource utilization and costs during the first year post-HTx compared to cardiomyopathy and myocarditis. Danielle Burstein et al. "Comparing resource utilization among pediatric heart transplant indications using a novel, merged data set from the United Network for Organ Sharing and the Pediatric Health Information Systems (UNOS-PHIS) databases," presented at the American College of Cardiology 67th Annual Scientific Session & Expo 2018.
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