A prospective multicenter feasibility study of a miniaturized implantable continuous flow ventricular assist device in smaller children with heart failure

BACKGROUND

There is no FDA-approved left ventricular assist device (LVAD) for smaller children permitting routine hospital discharge. Smaller children supported with LVADs typically remain hospitalized for months awaiting heart transplant-a major burden for families and a challenge for hospitals. We describe the initial outcomes of the Jarvik 2015, a miniaturized implantable continuous flow LVAD, in the NHLBI-funded Pumps for Kids, Infants, and Neonates (PumpKIN) study, for bridge-to-heart transplant.

METHODS

Children weighing 8 to 30 kg with severe systolic heart failure and failing optimal medical therapy were recruited at 7 centers in the United States. Patients with severe right heart failure and single-ventricle congenital heart disease were excluded. The primary feasibility endpoint was survival to 30 days without severe stroke or non-operational device failure.

RESULTS

Of 7 children implanted, the median age was 2.2 (range 0.7, 7.1) years, median weight 10 (8.2 to 20.7) kilograms; 86% had dilated cardiomyopathy; 29% were INTERMACS profile 1. The median duration of Jarvik 2015 support was 149 (range 5 to 188) days where all 7 children survived including 5 to heart transplant, 1 to recovery, and 1 to conversion to a paracorporeal device. One patient experienced an ischemic stroke on day 53 of device support in the setting of myocardial recovery. One patient required ECMO support for intractable ventricular arrhythmias and was eventually transplanted from paracorporeal biventricular VAD support. The median pump speed was 1600 RPM with power ranging from 1-4 Watts. The median plasma free hemoglobin was 19, 30, 19 and 30 mg/dL at 7, 30, 90 and 180 days or time of explant, respectively. All patients reached the primary feasibility endpoint. Patient-reported outcomes with the device were favorable with respect to participation in a full range of activities. Due to financial issues with the manufacturer, the study was suspended after consent of the eighth patient.

CONCLUSION

The Jarvik 2015 LVAD appears to hold important promise as an implantable continuous flow device for smaller children that may support hospital discharge. The FDA has approved the device to proceed to a 22-subject pivotal trial. Whether this device will survive to commercialization remains unclear because of the financial challenges faced by industry seeking to develop pediatric medical devices. (Supported by NIH/NHLBI HHS Contract N268201200001I, clinicaltrials.gov 02954497).

Contemporary Care and Outcomes of Critically-ill Children With Clinically Diagnosed Myocarditis

PURPOSE

To describe contemporary management and outcomes in children with myocarditis who are admitted to a cardiac intensive care unit (CICU) and to identify the characteristics associated with mortality.

METHODS

All patients in the Pediatric Cardiac Critical Care Consortium (PC4) registry between August 2014 and June 2021 who were diagnosed with myocarditis were included. Univariable analyses and multivariable logistic regression evaluated the factors associated with in-hospital mortality.

RESULTS

There were 847 CICU admissions for myocarditis in 51 centers. The median age was 12 years (IQR 2.7-16). In-hospital mortality occurred in 53 patients (6.3%), and 60 (7.1%) had cardiac arrest during admission. Mechanical ventilation was required in 339 patients (40%), and mechanical circulatory support (MCS) in 177 (21%); extracorporeal membrane oxygenation (ECMO)-only in 142 (16.7%), ECMO-to-ventricular assist device (VAD) in 20 (2.4%), extracorporeal cardiac resuscitation in 43 (5%), and VAD-only in 15 (1.8%) patients. MCS was associated with in-hospital mortality; 20.3% receiving MCS died compared to 2.5% without MCS (P < 0.001). Mortality rates were similar in ECMO-only, ECMO-to-VAD and VAD-only groups. The median time from CICU admission to ECMO was 2.0 hours (IQR 0-9.4) and to VAD, it was 9.9 days (IQR 6.3-16.8). Time to MCS was not associated with mortality. In multivariable modeling of patients' characteristics, smaller body surface area (BSA) and low eGFR were independently associated with mortality, and after including critical therapies, mechanical ventilation and ECMO were independent predictors of mortality.

CONCLUSION

This contemporary cohort of children admitted to CICUs with myocarditis commonly received high-resource therapies; however, most patients survived to hospital discharge and rarely received VAD. Smaller patient size, acute kidney injury and receipt of mechanical ventilation or ECMO were independently associated with mortality.

An integrated program to expand donor utilization in pediatric heart transplantation: Case report of successful transplant with multiple donor risk factors

BACKGROUND

Pediatric heart transplantation (HT) continues to be limited by the shortage of donor organs, distance constraints, and the number of potential donor offers that are declined due to the presence of multiple risk factors.

METHODS

We report a case of successful pediatric HT in which multiple risk factors were mitigated through a combination of innovative donor utilization improvement strategies.

RESULTS

An 11-year-old, 25-kilogram child with cardiomyopathy and pulmonary hypertension, on chronic milrinone therapy and anticoagulated with apixaban, was transplanted with a heart from a Hepatitis C virus positive donor and an increased donor-to-recipient weight ratio. Due to extended geographic distance, an extracorporeal heart preservation system (TransMedics™ OCS Heart) was used for procurement. No significant bleeding was observed post-operatively, and she was discharged by post-operative day 15 with normal biventricular systolic function. Post-transplant Hepatitis C virus seroconversion was successfully treated.

CONCLUSIONS

Heart transplantation in donors with multiple risk factor can be achieved with an integrative team approach and should be taken into consideration when evaluating marginal donors in order to expand the current limited donor pool in pediatric patients.

Weight Matching in Infant Heart Transplantation: A National Registry Analysis

BACKGROUND

Infants account for a significant proportion of pediatric heart transplantation but also suffer from a high waitlist mortality. Donor oversizing by weight-based criteria is common practice in transplantation and is prevalent in this group. We sought to analyze the impact of oversizing on outcomes in infants.

METHODS

Infant heart transplantations reported to the United Network for Organ Sharing from January 1994 to September 2019 were retrospectively analyzed. 2384 heart transplantation recipients were divided into quintiles (Q1-Q5) on the basis of donor-to-recipient weight ratio (DRWR). Multivariate Cox regression was used to estimate the effect of DRWR. The primary end point was graft survival at 1 year.

RESULTS

The median DRWR for each quintile was 0.90 (0.37-1.04), 1.17 (1.04-1.29), 1.43 (1.29-1.57), 1.74 (1.58-1.97), and 2.28 (1.97-5.00). Pairwise comparisons showed improved survival for Q3 and Q4 over each of the bottom 2 quintiles and the top quintile. Regression analyses found that Q3 and Q4 were protective against graft failure compared with the bottom 2 quintiles. There was no difference in hazard among the top 3 quintiles. Significant covariates included primary diagnosis, ischemia time, serum bilirubin level, transplantation year, mechanical ventilation at transplantation, and extracorporeal membrane oxygenation at transplantation. Sex, female-to-male transplantation, and mechanical circulatory support at transplantation were not significant in univariate analyses.

CONCLUSIONS

Modest oversizing by DRWR (1.29-1.97) is associated with increased survival and lower risk in infant heart transplantation. Additional investigation is needed to establish best practices for size matching in this population.

Pulmonary Vasodilator Therapy in Pediatric Patients on Ventricular Assist Device Support: A Single-Center Experience and Proposal for Use

Pediatric precapillary pulmonary hypertension can develop in response to systemic atrial hypertension. Systemic atrial decompression following ventricular assist device (VAD) implantation may not sufficiently lower pulmonary vascular resistance (PVR) to consider heart transplant candidacy. Prostacyclins have been used in adult VAD patients with success, but pediatric data on safety and efficacy in this population are limited. We sought to describe our center's experience to show its safety and to present our current protocol for perioperative use. We reviewed our use of prostacyclin therapy in pediatric patients on VAD support with high PVR from 2016 to 2021. Of the 17 patients who met inclusion, 12 survived to transplant and 1 is alive with VAD in situ . All patients survived posttransplant. With continuous intravenous (IV) epoprostenol or treprostinil therapy, there were no bleeding complications or worsening of end-organ function. A significant reduction was observed in vasoactive inotropic scores by 49% in the first 24 hours post-prostacyclin initiation. The proportion of patients surviving to transplant in this high-risk cohort is favorable. In conclusion, prostacyclins may be safe to use in patients with elevated PVR as part of their VAD and transplant course and may provide a transplant option in those otherwise not candidates.

Expanding use of the HeartMate 3 ventricular assist device in pediatric and adult patients within the Advanced Cardiac Therapies Improving Outcomes Network (ACTION)

BACKGROUND

We report current outcomes in patients supported with the HeartMate 3 (HM3) ventricular assist device in a multicenter learning network.

METHODS

The Advanced Cardiac Therapies Improving Outcomes Network database was queried for HM3 implants between 12/2017 and 5/2022. Clinical characteristics, postimplant course, and adverse events were collected. Patients were stratified according to body surface area (BSA) (<1.4 m2, 1.4-1.8 m2, and >1.8 m2) at device implantation.

RESULTS

During the study period, 170 patients were implanted with the HM3 at participating network centers, with median age 15.3years; 27.1% were female. Median BSA was 1.68 m2; the smallest patient was 0.73 m2 (17.7 kg). Most (71.8%) had a diagnosis of dilated cardiomyopathy. With a median support time of 102.5days, 61.2% underwent transplantation, 22.9% remained supported on device, 7.6% died, and 2.4% underwent device explantation for recovery; the remainder had transferred to another institution or transitioned to a different device type. The most common adverse events included major bleeding (20.8%) and driveline infection (12.9%); ischemic and hemorrhagic stroke were encountered in 6.5% and 1.2% of patients, respectively. Patients with BSA <1.4 m2 had a higher incidence of infection, renal dysfunction, and ischemic stroke.

CONCLUSIONS

In this updated cohort of predominantly pediatric patients supported with the HM3 ventricular assist device, outcomes are excellent with <8% mortality on device. Device-related adverse events including stroke, infection, and renal dysfunction were more commonly seen in smaller patients, highlighting opportunities for improvements in care.

The Fontan immunophenotype and post-transplant outcomes in children: A multi-institutional study

BACKGROUND

Patients after Fontan palliation represent a growing pediatric population requiring heart transplant (HTx) and often have lymphopenia (L) and/or hypogammaglobinemia that may be exacerbated by protein-losing enteropathy (PLE, P). The post-HTx effects of this altered immune phenotype are not well studied.

METHODS

In this study of the Pediatric Heart Transplant Society Registry, 106 Fontan patients who underwent HTx between 2005 and 2018 were analyzed. The impact of lymphopenia and PLE on graft survival, infection, rejection, and malignancy was analyzed at 1 and 5 years post-HTx.

RESULTS

The following combinations of lymphopenia and PLE were noted: +L+P, n = 37; +L-P, n = 23; -L+P, n = 10; and -L-P, n = 36. Graft survival between the groups was similar within the first year after transplant (+L+P: 86%, +L-P: 86%, -L+P: 87%, -L-P: 89%, p = .9). Freedom from first infection post-HTx was greatest among -L-P patients compared to patients with either PLE, lymphopenia, or both; with a 22.1% infection incidence in the -L-P group and 41.4% in all others. These patients had a significantly lower infection rate in the first year after HTx (+L+P: 1.03, +L-P: 1, -L+P: 1.3, -L-P: 0.3 infections/year, p < .001) and were similar to a non-single ventricle CHD control group (0.4 infections/year). Neither freedom from rejection nor freedom from malignancy 1 and 5 years post-HTx, differed among the groups.

CONCLUSIONS

Fontan patients with altered immunophenotype, with lymphopenia and/or PLE, are at increased risk of infection post-HTx, although have similar early survival and freedom from rejection and malignancy. These data may encourage alternative immunosuppression strategies and enhanced monitoring for this growing subset of patients.

Evaluating predicted heart mass in adolescent heart transplantation

BACKGROUND

Predicted Heart Mass (PHM) has emerged as an attractive size matching metric in adult cardiac transplantation. However, since PHM was derived from a healthy adult cohort, its generalizability to the pediatric population is unclear. We hypothesize that PHM can be extended to older adolescents, and potentially broaden the donor pool available to this group.

METHODS

The United Network for Organ Sharing database was retrospectively analyzed for patients aged 13 to 18 undergoing heart transplantation. Recipients were divided into quintiles (Q1-Q5) based on donor-to-recipient predicted heart mass ratios (PHMR). Primary end-point was graft survival at 5 years.

RESULTS

Two thousand sixty-one adolescent heart transplant recipients between January 1994 and September 2019 were retrospectively analyzed. The median PHMR's for each quintile was 0.84 (0.59-0.92), 0.97 (0.92-1.02), 1.08 (1.02-1.14), 1.21 (1.14-1.30), and 1.44 (1.30-2.31). Kaplan-Meier survival curves demonstrated comparable survival across all quintiles of PHMR (p = 0.9). Multivariate Cox regression showed no significant difference in graft failure of the outer quintiles when compared to the middle quintile (Q1: 1.04 HR, p = 0.80; Q2: 1.02 HR, p = 0.89; Q4: 1.19 HR, p = 0.28; Q5: 1.02 HR, p = 0.89). Significant covariates included transplant year (HR: 0.95, p < 0.0001), serum bilirubin (HR: 1.04, p = 0.0004), ECMO at transplantation (HR: 2.85, p < 0.0001), and underlying diagnosis of dilated cardiomyopathy (vs congenital heart disease, HR: 0.66, p = 0.0004).

CONCLUSIONS

Matching by PHM is not associated with survival or risk in adolescent heart transplant recipients. Our results underscore the ongoing need to develop an improved size-matching method in pediatric heart transplantation.

Fatal nocardiosis infection in a pediatric patient with an immunodeficiency after heart re-transplantation

BACKGROUND

Nocardia infections are rare opportunistic infections in SOT recipients, with few reported pediatric cases. Pediatric patients with single ventricle congenital heart defects requiring HT may be more susceptible to opportunistic infections due to a decreased T-cell repertoire from early thymectomy and potential immunodeficiencies related to their congenital heart disease. Other risk factors in SOT recipients include the use of immunosuppressive medications and the development of persistent lymphopenia, delayed count recovery and/or lymphocyte dysfunction.

METHODS

We report the case of a patient with hypoplastic left heart syndrome who underwent neonatal congenital heart surgery (with thymectomy) prior to palliative surgery and 2 HTs.

RESULTS

After developing respiratory and neurological symptoms, the patient was found to be positive for Nocardia farcinica by BAL culture and cerebrospinal fluid PCR. Immune cell phenotyping demonstrated an attenuated T and B-cell repertoire. Despite antibiotic and immunoglobulin therapy, his symptoms worsened and he was subsequently discharged with hospice care.

CONCLUSION

Pediatric patients with a history of congenital heart defects who undergo neonatal thymectomy prior to heart transplantation and a long-term history of immunosuppression should undergo routine immune system profiling to evaluate for T- and B-cell deficiency as risk factors for opportunistic infection. Such patients could benefit from long-term therapy with TMP/SMX for optimal antimicrobial prophylaxis, with desensitization as needed for allergies. Disseminated nocardiosis should be considered when evaluating acutely ill SOT recipients, especially those with persistent lymphopenia and known or suspected secondary immunodeficiencies.

Characteristics and Outcomes of Pediatric Patients With a Ventricular Assist Device Presenting to the Emergency Department

OBJECTIVES

A growing number of children receive support from left ventricular assist devices (LVADs) in the outpatient setting. Unexpected complications of LVAD support occur that require emergent management, and no studies examine how pediatric LVAD patients present to the emergency department (ED). The goals of this study were (1) to describe frequency of visits, clinical characteristics, adverse events, and outcomes of LVAD-supported children treated in ED settings and (2) to evaluate for associations between specified patient outcomes and ED care location.

METHODS

This was a retrospective cohort study of children in a single-center outpatient VAD program who presented to several EDs during a 10-year period. We defined adverse events according to the Advanced Cardiac Therapies Improving Outcomes Network registry guidelines. Secondary analysis evaluated for associations between specified patient outcomes (adverse events, hospitalizations, intensive care unit admissions) and ED care location (institutional vs other ED).

RESULTS

Of 104 subjects with LVAD implantations during the study period, 30 (28.8%) transitioned to outpatient care. Among subjects in the outpatient VAD program, 24 (80%) of 30 had 54 visits to various EDs over 141.9 patient-months. The median age at time of ED visit was 13.5 years (range, 7.2-17.9 years). The median number of visits per subject was 1 (range, 0-6). The most common complaints on arrival to the ED were vomiting or abdominal pain (16.7%), fever (15.3%), and headache (13.9%). Seventeen adverse events occurred during 14 (25.9%) of 54 ED visits. The most common adverse events were major infection (33.3%) and right heart failure (16.7%). Hospital admission resulted from 41 (75.9%) of 54 ED visits, including 17 (41.5%) of 41 to a cardiovascular intensive care unit. Care at a nonspecialty ED was associated with a higher rate of hospitalization (93.8% vs 68.4%, P = 0.049). During the study period, 4 subjects (13.3%) died, including 1 patient on destination therapy, 1 with multisystem organ failure due to cardiogenic shock, and 2 with hemorrhagic stroke. No patient died while in the ED.

CONCLUSIONS

Among subjects in a single outpatient pediatric VAD program presenting to the ED, the most common complaints were abdominal pain/vomiting, fever, and headache. The most common adverse events were major infection and right heart failure. Subjects had a high rate of ED utilization and hospital admission.

Expanded cardiovascular phenotype of Myhre syndrome includes tetralogy of Fallot suggesting a role for SMAD4 in human neural crest defects

Tetralogy of Fallot (ToF) can be associated with a wide range of extracardiac anomalies, with an underlying etiology identified in approximately 10% of cases. Individuals affected with Myhre syndrome due to recurrent SMAD4 mutations frequently have cardiovascular anomalies, including congenital heart defects. In addition to two patients in the literature with ToF, we describe five additional individuals with Myhre syndrome and classic ToF, ToF with pulmonary atresia and multiple aorto-pulmonary collaterals, and ToF with absent pulmonary valve. Aorta hypoplasia was documented in one patient and suspected in another two. In half of these individuals, postoperative cardiac dysfunction was thought to be more severe than classic postoperative ToF repair. There may be an increase in right ventricular pressure, and right ventricular dysfunction due to free pulmonic regurgitation. Noncardiac developmental abnormalities in our series and the literature, including corectopia, heterochromia iridis, and congenital miosis suggest an underlying defect of neural crest cell migration in Myhre syndrome. We advise clinicians that Myhre syndrome should be considered in the genetic evaluation of a child with ToF, short stature, unusual facial features, and developmental delay, as these children may be at risk for increased postoperative morbidity. Additional research is needed to investigate the hypothesis that postoperative hemodynamics in these patients may be consistent with restrictive myocardial physiology.

Clinical and hemodynamic characteristics of the pediatric failing Fontan

AIM

To describe the clinical and hemodynamic characteristics of Fontan failure in children listed for heart transplant.

METHODS

In a nested study of the Pediatric Heart Transplant Society, 16 centers contributed information on Fontan patients listed for heart transplant between 2005and 2013. Patients were classified into four mutually exclusive phenotypes: Fontan with abnormal lymphatics (FAL), Fontan with reduced systolic function (FRF), Fontan with preserved systolic function (FPF), and Fontan with "normal" hearts (FNH). Primary outcome was waitlist and post-transplant mortality.

RESULTS

177 children listed for transplant were followed over a median 13 (IQR 4-31) months, 84 (47%) were FAL, 57 (32%) FRF, 22 (12%) FNH, and 14 (8%) FPF. Hemodynamic characteristics differed between the 4 groups: Fontan pressure (FP) was most elevated with FPF (median 22, IQR 18-23, mmHg) and lowest with FAL (16, 14-20, mmHg); cardiac index (CI) was lowest with FRF (2.8, 2.3-3.4, L/min/m²). In the entire cohort, 66% had FP >15 mmHg, 21% had FP >20 mmHg, and 10% had CI <2.2 L/min/m². FRF had the highest risk of waitlist mortality (21%) and FNH had the highest risk of post-transplant mortality (36%).

CONCLUSIONS

Elevated Fontan pressure is more common than low cardiac output in pediatric failing Fontan patients listed for transplant. Subtle hemodynamic differences exist between the various phenotypes of pediatric Fontan failure. Waitlist and post-transplant mortality risks differ by phenotype.

Berlin Heart EXCOR and ACTION post-approval surveillance study report

BACKGROUND

The Berlin Heart EXCOR Pediatric (EXCOR) ventricular assist device (VAD) was introduced in North America nearly 2 decades ago. The EXCOR was approved under Humanitarian Device Exemption status in 2011 and received post-market approval (PMA) in 2017 from Food and Drug Administration. Since the initial approval, the field of pediatric mechanical circulatory support has changed, specifically with regard to available devices, anticoagulation strategies, and the types of patients supported. This report summarizes the outcomes of patients supported with EXCOR from the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry. These data were part of the PMA surveillance study (PSS) required by the Food and Drug Administration.

METHODS

ACTION is a learning collaborative of over 40 pediatric heart failure programs worldwide, which collects data for all VAD implantations as one of its initiatives. All patients in North America with EXCOR implants reported to ACTION from 2018 to 2020 (n = 72) who had met an outcome were included in the EXCOR PSS group. This was compared with a historical, previously reported Berlin Heart EXCOR study group (Berlin Heart study [BHS] group, n = 320, 2007‒2014).

RESULTS

Patients in the PSS group were younger, were smaller in weight/body surface area, were more likely to have congenital heart disease, and were less likely to receive a bi-VAD than those in the BHS group. Patients in the PSS group were less likely to be in Interagency Registry for Mechanically Assisted Circulatory Support Profile 1 and were supported for a longer duration. The primary anticoagulation therapy for 92% of patients in the PSS group was bivalirudin. Success, defined as being transplanted, being weaned for recovery, or being alive on a device at 180 days after implantation, was 86% in the PSS group compared with 76% in the BHS group. Incidence of stroke was reduced by 44% and the frequency of pump exchange by 40% in the PSS group compared with those in the BHS group. Similarly, all other adverse events, including major bleeding, were reduced in the PSS group.

CONCLUSIONS

The PSS data, collected through ACTION, highlight the improvement in outcomes for patients supported with EXCOR compared with the outcomes in a historical cohort. These findings may be the result of changes in patient care practices over time and collaborative learning.

A Quality Bundle to Support High-Risk Pediatric Ventricular Assist Device Implantation

Pediatric ventricular assist device (VAD) implantation outcomes are increasingly promising for children with dilated cardiomyopathy and advanced decompensated heart failure (ADHF). VAD placement in patients with clinical features such as complex congenital cardiac anatomy, small body size, or major comorbidities remains problematic. These comorbidities have been traditionally prohibitive for VAD consideration leaving these children as a treatment-orphaned population. Here we describe the quality bundle surrounding these patients with ADHF considered high risk for VAD implantation at our institution. Over a 7-year period, a quality bundle aimed at the peri-operative care for children with high-risk features undergoing VAD implantation was incrementally implemented at a tertiary children's hospital. Patients were considered high risk if they were neonates (< 30 days), had single-ventricle physiology, non-dilated cardiomyopathy, biventricular dysfunction, or significant comorbidities. The quality improvement bundle evolved to include (1) structured team-based peri-operative evaluation, (2) weekly VAD rounds addressing post-operative device performance, (3) standardized anticoagulation strategies, and (4) a multidisciplinary system for management challenges. These measures aimed to improve communication, standardize management, allow for ongoing process improvement, and incorporate principles of a high-reliability organization. Between January 2010 and December 2017, 98 patients underwent VAD implantation, 48 (49%) of which had high-risk comorbidities and a resultant cohort survival-to-transplant rate of 65%. We report on the evolution of a quality improvement program to expand the scope of VAD implantation to patients with high-risk clinical profiles. This quality bundle can serve as a template for future large-scale collaborations to improve outcomes in these treatment-orphaned subgroups.

Long-term surveillance biopsy: Is it necessary after pediatric heart transplant?

Due to limited and conflicting data in pediatric patients, long-term routine surveillance endomyocardial biopsy (RSB) in pediatric heart transplant (HT) remains controversial. We sought to characterize the rate of positive RSB and determine factors associated with RSB-detected rejection. Records of patients transplanted at a single institution from 1995 to 2015 with >2 year of post-HT biopsy data were reviewed for RSB-detected rejections occurring >2 year post-HT. We illustrated the trajectory of significant rejections (ISHLT Grade ≥3A/2R) among total RSB performed over time and used multivariable logistic regression to model the association between time and risk of rejection. We estimated Kaplan-Meier freedom from rejection rates by patient characteristics and used the log-rank test to assess differences in rejection probabilities. We identified the best-fitting Cox proportional hazards regression model. In 140 patients, 86% did not have any episodes of significant RSB-detected rejection >2 year post-HT. The overall empirical rate of RSB-detected rejection >2 year post-HT was 2.9/100 patient-years. The percentage of rejection among 815 RSB was 2.6% and remained stable over time. Years since transplant remained unassociated with rejection risk after adjusting for patient characteristics (OR = 0.98; 95% CI 0.78-1.23; P = 0.86). Older age at HT was the only factor that remained significantly associated with risk of RSB-detected rejection under multivariable Cox analysis (P = 0.008). Most pediatric patients did not have RSB-detected rejection beyond 2 years post-HT, and the majority of those who did were older at time of HT. Indiscriminate long-term RSB in pediatric heart transplant should be reconsidered given the low rate of detected rejection.

Haemodynamic profiles of children with end-stage heart failure

Aims

To evaluate associations between haemodynamic profiles and symptoms, end-organ function and outcome in children listed for heart transplantation.

Methods and results

Children <18 years listed for heart transplant between 1993 and 2013 with cardiac catheterization data [pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), and cardiac index (CI)] in the Pediatric Heart Transplant Study database were included. Outcomes were New York Heart Association (NYHA)/Ross classification, renal and hepatic dysfunction, and death or clinical deterioration while on waitlist. Among 1059 children analysed, median age was 6.9 years and 46% had dilated cardiomyopathy. Overall, 58% had congestion (PCWP >15 mmHg), 28% had severe congestion (PCWP >22 mmHg), and 22% low cardiac output (CI < 2.2 L/min/m2). Twenty-one per cent met the primary outcome of death (9%) or clinical deterioration (12%). In multivariable analysis, worse NYHA/Ross classification was associated with increased PCWP [odds ratio (OR) 1.03, 95% confidence interval (95% CI) 1.01-1.07, P = 0.01], renal dysfunction with increased RAP (OR 1.04, 95% CI 1.01-1.08, P = 0.007), and hepatic dysfunction with both increased PCWP (OR 1.03, 95% CI 1.01-1.06, P < 0.001) and increased RAP (OR 1.09, 95% CI 1.06-1.12, P < 0.001). There were no associations with low output. Death or clinical deterioration was associated with severe congestion (OR 1.6, 95% CI 1.2-2.2, P = 0.002), but not with CI alone. However, children with both low output and severe congestion were at highest risk (OR 1.9, 95% CI 1.1-3.5, P = 0.03).

Conclusion

Congestion is more common than low cardiac output in children with end-stage heart failure and correlates with NYHA/Ross classification and end-organ dysfunction. Children with both congestion and low output have the highest risk of death or clinical deterioration.

The End-of-Life Experience of Pediatric Heart Transplant Recipients

CONTEXT

Despite advances in therapies, many pediatric heart transplant (Htx) recipients will die prematurely. We characterized the circumstances surrounding death in this cohort, including location of death and interventions performed in the final 24 hours.

METHODS

We reviewed all patients who underwent Htx at Lucile Packard Children's Hospital, Stanford, survived hospital discharge, and subsequently died between July 19, 2007 and September 13, 2015. The primary outcome studied was location of death, characterized as inpatient, outpatient, or emergency department. Circumstances of death (withdrawal of life-sustaining treatment, death during resuscitation, or death without resuscitation with/without do not resuscitate) and interventions performed in the last 24 hours of life were also analyzed.

RESULTS

Twenty-three patients met the entry criteria. The median age at death was 12 (range 2-20) years, and the median time between transplant and death was 2.8 (range 0.8-11) years. Four (17%) died at home, and three (13%) died in the emergency department. Sixteen (70%) patients died in the hospital, 14 of 16 (88%) of whom died in an intensive care unit. Five of 23 (22%) patients experienced attempted resuscitation. Interventions performed in the last 24 hours of life included intubation (74%), mechanical support (30%), and dialysis (22%). Most patients had a recent outpatient clinical encounter with normal graft function within 60 days of dying.

CONCLUSIONS/LESSONS LEARNED

Death in children after Htx often occurs in the inpatient setting, particularly the intensive care unit. Medical interventions, including attempted resuscitation, are common at the end of life. Given the difficulty in anticipating life-threatening events, earlier discussions with patients regarding end-of-life wishes are appropriate, even in those with normal graft function.

Functional status of United States children supported with a left ventricular assist device at heart transplantation

BACKGROUND

As survival with pediatric left ventricular assist devices (LVADs) has improved, decisions regarding the optimal support strategy may depend more on quality of life and functional status (FS) rather than mortality alone. Limited data are available regarding the FS of children supported with LVADs. We sought to compare the FS of children supported with LVADs vs vasoactive infusions to inform decision making around support strategies.

METHODS

Organ Procurement and Transplant Network data were used to identify all United States children aged between 1 and 21 years at heart transplant (HT) between 2006 and 2015 for dilated cardiomyopathy and supported with an LVAD or vasoactive infusions alone at HT. FS was measured using the 10-point Karnofsky and Lansky scale.

RESULTS

Of 701 children who met the inclusion criteria, 430 (61%) were supported with vasoactive infusions, and 271 (39%) were supported with an LVAD at HT. Children in the LVAD group had higher median FS scores at HT than children in the vasoactive infusion group (6 vs 5, p < 0.001) but lower FS scores at listing (4 vs 6, p < 0.001). The effect persisted regardless of patient location at HT (home, hospital, intensive care) or device type. Discharge by HT occurred in 46% of children in the LVAD group compared with 26% of children in the vasoactive infusion cohort (p = 0.001). Stroke was reported at HT in 3% of children in the LVAD cohort and in 1% in the vasoactive infusion cohort (p = 0.04).

CONCLUSIONS

Among children with dilated cardiomyopathy undergoing HT, children supported with LVADs at HT have higher FS than children supported with vasoactive infusions at HT, regardless of device type or hospitalization status. Children supported with LVADs at HT were more likely to be discharged from the hospital but had a higher prevalence of stroke at HT.

Si nanowire-gold nanoparticles heterostructures for surface enhanced Raman spectroscopy

Here, we present a method for the fabrication of silicon (Si) nanowires and Si nanowire-gold nanoparticles (AuNPs) heterostructures for surface-enhanced Raman scattering (SERS) effect. Branched Si nanowires were grown in atmospheric pressure chemical vapor deposition (CVD) process. Further decoration of these nanowires was achieved by a galvanic deposition of gold followed by annealing procedure. This resulted in Si nanowires-AuNPs heterostructures with controlled size and inter-particle spacing. Furthermore, the fabricated heterostructures were studied for Raman signal enhancement of the low concentration (∼10-6 M) dye (Rhodamine 6G, R6G). It was observed that heterostructuring of SiNWs with AuNPs led to improvement of R6G signals as compared to AuNPs dispersed on flat Si substrate.

Growth of silicon nanowires-based heterostructures and their plasmonic modeling

Complex nanoscale architectures based on gold nanoparticles (AuNPs) can result in spatially-resolved plasmonics. Herein, we demonstrate the growth of silicon nanowires (SiNWs), heterostructures of SiNWs decorated with AuNPs, and SiNWs decorated with graphene shells encapsulated gold nanoparticles (GNPs). The fabrication approach combined CVD growth of nanowires and graphene with direct nucleation of AuNPs. The plasmonic or optical properties of SiNWs and their complex heterostructures were simulated using discrete dipole approximation method. Extinction efficiency spectra peak for SiNW significantly red-shifted (from 512 nm to 597 nm or 674 nm) after decoration with AuNPs, irrespective of the incident wave vector. Finally, SiNW decorated with GNPs resulted in incident wave vector-dependent extinction efficiency peak. For this case, wave vector aligned with the nanowire axial direction showed a broad peak at ∼535 nm. However, significant scattering and no peak was observed when aligned in radial direction of the SiNWs. Such spatially-resolved and tunable plasmonic or optical properties of nanoscale heterostructures hold strong potential for optical sensor and devices.