Impact of center volume on outcomes after ventricular assist device implantation in pediatric patients: An analysis of the STS-Pedimacs database.

BACKGROUND: To date, no pediatric studies have highlighted the impact of center's ventricular assist device (VAD) volumes on post implant outcomes. METHODS: Children (age <19) enrolled in Pedimacs undergoing initial left ventricular assist device implantation from 2012 to 2020 were included. Center volume was analyzed as a continuous and categorical variable. For categorical analysis, center volumes were divided as: low volume (1-15 implants), medium volume (15-30 implants), and high volume (>30 implants) during our study period. Patient characteristics and outcomes were compared by center's VAD volumes. RESULTS: Of 44 centers, 16 (36.4%) were low, 11 (25%) were medium, and 17 (38.6%) were high-volume centers. Children at high-volume centers were least likely intubated, sedated, or paralyzed, and most likely ambulating preimplant (p < 0.05 for all). Center's VAD volumes were not a significant risk factor for mortality post implant when treated as a continuous or a categorical variable (p > 0.05). Compared to low volume, children at high-volume centers had fewer early neurological events. Compared to medium volume, those at high-volume centers had fewer late bleeding events (p < 0.05 for all). There were no significant differences in survival after an adverse event by hospital volumes (p > 0.05). CONCLUSIONS: Although hospital volume does not affect post-VAD implant mortality, pediatric centers with higher VAD volumes have fewer patients intubated, sedated, paralyzed pre implant, and have lower adverse events. Failure to rescue was not significantly different between low, medium, and high-volume VAD centers.

Considerations for Advanced Heart Failure Consultation in Individuals With Fontan Circulation: Recommendations From ACTION.

Individuals with Fontan circulation are at risk of late mortality from both cardiac and noncardiac causes. Despite the known risk of mortality, referral indications for advanced heart failure care vary between centers, and many individuals die from Fontan circulation-related complications either after late consideration for advanced heart failure therapies or having never seen a heart failure specialist. There is a critical need for guidelines to direct appropriately timed referral for advanced heart failure consultation. The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) Fontan Committee has developed recommended thresholds for advanced heart failure referral to guide primary cardiologists. These recommendations are divided into 4 categories of clinical Fontan circulatory dysfunction including (1) cardiac/systemic ventricular dysfunction, (2) Fontan pathway dysfunction, (3) lymphatic dysfunction, and (4) extracardiac dysfunction.

Initial multicenter experience with ventricular assist devices in children and young adults with muscular dystrophy: An ACTION registry analysis.

PURPOSE: Cardiac disease results in significant morbidity and mortality in patients with muscular dystrophy (MD). Single centers have reported their ventricular assist device (VAD) experience in specific MDs and in limited numbers. This study sought to describe the outcomes associated with VAD therapy in an unselected population across multiple centers. METHODS: We examined outcomes of patients with MD and dilated cardiomyopathy implanted with a VAD at Advanced Cardiac Therapies Improving Outcomes Network (ACTION) centers from 9/2012 to 9/2020. RESULTS: A total of 19 VADs were implanted in 18 patients across 12 sites. The majority of patients had dystrophinopathy (66%) and the median age at implant was 17.2 years (range 11.7-29.5). Eleven patients were non-ambulatory (61%) and 6 (33%) were on respiratory support pre-VAD. Five (28%) patients were implanted as a bridge to transplant, 4 of whom survived to transplant. Of 13 patients implanted as bridge to decision or destination therapy, 77% were alive at 1 year and 69% at 2 years. The overall frequencies of positive outcome (transplanted or alive on device) at 1 year and 2 years were 84% and 78%, respectively. Two patients suffered a stroke, 2 developed sepsis, 1 required tracheostomy, and 1 experienced severe right heart failure requiring right-sided VAD. CONCLUSIONS: This study demonstrates the potential utility of VAD therapies in patients with muscular dystrophy. Further research is needed to further improve outcomes and better determine which patients may benefit most from VAD therapy in terms of survival and quality of life.

Prolonged hospital length of stay after pediatric heart transplantation: A machine learning and logistic regression predictive model from the Pediatric Heart Transplant Society.

BACKGROUND: Heart transplantation (HT) is the gold standard for managing end-stage heart failure. Multiple quality metrics, including length of stay (LOS), have been used in solid organ transplantation. However, limited data are available regarding trends and factors influencing LOS after pediatric HT. We hypothesized that various donor, peri-transplant and recipient factors affect LOS after pediatric HT. METHODS: We analyzed patients <18years at time of HT from January 2005 to December 2018 in the Pediatric Heart Transplant Society database, and examined LOS trends, defined prolonged LOS (PLOS = LOS>30days after HT), identified factors associated with PLOS and assessed outcomes. RESULTS: Of 4827 patients undergoing HT, 4414 patients were discharged and included for analysis. Overall median LOS was 19days[13,34]. Median LOS was longer in patients with congenital heart disease(CHD = 25days[15,43] than with cardiomyopathy(CM = 17days[12,27] across all ages. Median LOS in age <1year was 26-days[16,45.5] and in age >10year was 16days[11,26]. PLOS was seen in 1313 patients(30%). Patients with PLOS were younger, smaller and had longer CPB times. There was no difference in utilization of VAD at HT between groups, however, ECMO use at listing(8.45% vs 2.93%,p < 0.05) and HT was higher in the PLOS group(9.22% vs 1.58%,p < 0.05). PLOS was more common in patients with previous surgery, CHD, single ventricle physiology, recipient history of cardiac arrest or CPR, end organ dysfunction, lower GFR, use of mechanical ventilation at HT and Status 1A at HT. CONCLUSION: We present novel findings of LOS distribution and define PLOS after pediatric HT, providing a quality metric for individual programs to utilize and study in their practice.

SARS-CoV-2 Antibody Serology Testing in a 3-Month-Old Organ Donor: A Case Report and Review of Available Literature.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a highly prevalent infectious disease. Currently, organs are not being transplanted from donors who are SARS-CoV-2 positive. It remains unclear as to how to differentiate active from recovered patients. We report our recent experience of a 3-month-old deceased organ donor who died as the result of an anoxic brain injury after a cardiopulmonary arrest (presumed sudden infant death syndrome). The child was born to a mother presumed to have coronavirus disease 2019. The donor tested negative for SARS-CoV-2 reverse transcriptase-polymerase chain reaction and positive for SARS-CoV-2 immunoglobulin A antibodies. We suspect this is the first known report of its kind and noteworthy for the organ donation and transplantation community.

Right heart failure considerations in pediatric ventricular assist devices.

Right heart failure (RHF) is a vexing problem in children after left ventricular assist device (LVAD) implantation that can negatively impact transplant candidacy and survival. Anticipation, prevention, early identification and appropriate medical and device management of RHF are important to successful LVAD outcomes. However, there is limited pediatric evidence to guide practice. This pediatric-focused review summarizes the relevant literature and describes the harmonized approach to RHF from the Advanced Cardiac Therapies Improving Outcomes Network (ACTION). This review seeks to improve RHF outcomes through the sharing of best practices and experience across the pediatric VAD community.

Heart Failure After Cavopulmonary Connection: Conversion to Biventricular Circulatory Support.

Mechanical support of patients with superior cavopulmonary connection is challenging; multiple factors contribute to failure: elevated pulmonary vascular resistance, aortopulmonary collateral flow, venovenous collaterals, ventricular dysfunction, and atrioventricular valve regurgitation. We report 2 cases of conversion from a single ventricle circulation to biventricular mechanical support by reestablishing caval continuity. Both patients have demonstrated recovery of end-organ function and participation in rehabilitation. This method of support results in improved systemic venous pressures and pulmonary blood flow compared with systemic mechanical circulatory support with a cavopulmonary connection and transfers some of the complexity of the transplant to the ventricular assist device implant.

Utilization and Outcomes of Children Treated with Direct Thrombin Inhibitors on Paracorporeal Ventricular Assist Device Support.

Thrombotic and bleeding complications have historically been major causes of morbidity and mortality in pediatric ventricular assist device (VAD) support. Standard anticoagulation with unfractionated heparin is fraught with problems related to its heterogeneous biochemical composition and unpredictable pharmacokinetics. We sought to describe the utilization and outcomes in children with paracorporeal VAD support who are treated with direct thrombin inhibitors (DTIs) antithrombosis therapy. Retrospective multicenter review of all pediatric patients (aged <19 years) treated with a DTI (bivalirudin or argatroban) on paracorporeal VAD support, examining bleeding and thrombotic adverse events. From May 2012 to 2018, 43 children (21 females) at 10 centers in North America, median age 9.5 months (0.1-215 months) weighing 8.6 kg (2.8-150 kg), were implanted with paracorporeal VADs and treated with a DTI. Diagnoses included cardiomyopathy 40% (n = 17), congenital heart disease 37% (n = 16; single ventricle n = 5), graft vasculopathy 9% (n = 4), and other 14% (n = 6). First device implanted included Berlin Heart EXCOR 49% (n = 21), paracorporeal continuous flow device 44% (n = 19), and combination of devices in 7% (n = 3). Adverse events on DTI therapy included; major bleeding in 16% (n = 7) (2.6 events per 1,000 patient days of support on DTI), and stroke 12% (n = 5) (1.7 events per 1,000 patient days of support on DTI). Overall survival to transplantation (n = 30) or explantation (n = 8) was 88%. This is the largest multicenter experience of DTI use for anticoagulation therapy in pediatric VAD support. Outcomes are encouraging with lower major bleeding and stroke event rate than that reported in literature using other anticoagulation agents in pediatric VAD support.

The Creation of a Pediatric Health Care Learning Network: The ACTION Quality Improvement Collaborative.

Improving the outcomes of pediatric patients with congenital heart disease with end-stage heart failure depends on the collaboration of all stakeholders; this includes providers, patients and families, and industry representatives. Because of the rarity of this condition and the heterogeneity of heart failure etiologies that occur at pediatric centers, learnings must be shared between institutions and all disciplines to move the field forward. To foster collaboration, excel discovery, and bring data to the bedside, a new, collaborative quality improvement science network-ACTION (Advanced Cardiac Therapies Improving Outcomes Network)-was developed to meet the needs of the field. Existing gaps in care and the methods of improvement that will be used are described, along with the mission and vision, utility of real-world data for regulatory purposes, and the organizational structure of ACTION is described.

Early experience with the HeartMate 3 continuous-flow ventricular assist device in pediatric patients and patients with congenital heart disease: A multicenter registry analysis.

BACKGROUND: The HeartMate 3 ventricular assist device (VAD) is a newer centrifugal continuous-flow VAD used for bridge-to-transplant and destination therapy in adults. However, there is limited experience regarding its use in children and adults with complex congenital heart disease (CHD). METHODS: The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) is a multicenter learning network comprised of pediatric hospitals implanting VADs in children and adults with complex CHD. We examined the outcomes of patients undergoing HeartMate 3 implantation at an ACTION center between December 2017 and September 2019. RESULTS: The HeartMate 3 was implanted in 35 patients at 9 ACTION centers, with a median age of 15.7 (8.8-47.3) years, median weight of 65.7 (19.1-114.1) kg, and median body surface area (BSA) of 1.74 (0.78-2.36) m2. Of the cohort, 14 patients (40%) weighed <60 kg. Diagnoses included dilated cardiomyopathy (63%), dilated cardiomyopathy in neuromuscular disease (20%), and CHD (17%). Of those with CHD, most had a Fontan circulation. With a median 78 days of follow-up, there was 1 death on device (97% survival); 20 out of 35 (57%) underwent transplantation with no post-transplantation mortality. There were no episodes of stroke or pump thrombosis. CONCLUSIONS: Use of the HeartMate 3 in ACTION centers was associated with a low incidence of mortality and adverse events. Patients as small as 19 kg (BSA 0.78 m2) were successfully implanted and supported, indicating that this device may be appropriate for older children and small adults.

Third Annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) Report: Preimplant Characteristics and Outcomes.

BACKGROUND: The influence of ventricular assist device (VAD) use in the care of children with end-stage heart failure is growing rapidly through increasing numbers, new devices, expanding indications, and improving outcomes. Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), a National Institutes of Health-sponsored United States database, provides a platform to understand this emerging population. METHODS: Between September 19, 2012, and December 31, 2017, 30 hospitals implanted 508 devices in 423 patients aged younger than 19 years. This past year was one of evolution for the database as its management was transitioned to The Society of Thoracic Surgery; therefore, this report does not include data from institutions not under contract by August 1, 2018. RESULTS: Of the 423 patients, the diagnosis was cardiomyopathy in 261 (62%), myocarditis in 48 (11%), other in 28 (7%), and congenital heart disease (CHD) in 86 (20%), with 52 of these patients having single-ventricle physiology. The two most common support strategies included left VAD in 342 (81%) and biventricular assist device in 64 (15%). Positive outcome (alive on device or bridge to transplantation/recovery) was 80% at 6 months (overall mortality of 20%). The patient cohort for implantable continuous-flow (IC) pumps (n = 197; age at implant, 13.4 ± 3.8 years; 19% Interagency Registry for Mechanically Assisted Circulatory Support [Intermacs] profile 1, 21% intubated at implant, and 12% with CHD) was significantly different from the paracorporeal continuous-flow (PC) pump cohort (n = 79; age, 3.9 ± 5.2 years; 49% Intermacs profile 1, 86% intubated at implant, and 38% with CHD) and the paracorporeal pulsatile (PP) pump cohort (n = 121; age, 3.3 ± 3.9 years; 41% Intermacs profile 1, 77% intubated at implant, and 21% with CHD). Consistent with their cohort composition, device type positive outcomes at 6 months were PC, 63%; PP, 77%; and IC, 92%. Parametric hazard modeling showed an early hazard for death was associated with Intermacs profile 1, biventricular assist device, percutaneous devices, PC devices, small-volume institutions, low age, and low weight, whereas a constant hazard was associated with intubation and liver dysfunction at time of implant. CONCLUSIONS: IC VADs are the most common VAD type placed in children. The positive outcomes for the IC VADs exceed 90% at 6 months, which may represent our field's maturation in both patient selection and timing of implantation. The PP/PC devices are currently limited to supporting our most challenging patients, those weighing less than 20 kg and those with CHD. The introduction of new devices and our communities' commitment to shared learning and improvement will lead to more pediatric lives saved by VAD support and will also focus on improving the quality of life of children supported with VADs.

Post-transplant outcomes in pediatric ventricular assist device patients: A PediMACS-Pediatric Heart Transplant Study linkage analysis.

BACKGROUND: Pediatric ventricular assist device (VAD) support as bridge to transplant has improved waitlist survival, but the effects of pre-implant status and VAD-related events on post-transplant outcomes have not been assessed. This study is a linkage analysis between the PediMACS and Pediatric Heart Transplant Study databases to determine the effects of VAD course on post-transplant outcomes. METHODS: Database linkage between October 1, 2012 and December 31, 2015 identified 147 transplanted VAD patients, the primary study group. The comparison cohort was composed of 630 PHTS patients without pre-transplant VAD support. The primary outcome was post-transplant survival, with secondary outcomes of post-transplant length of stay, freedom from infection and freedom from rejection. RESULTS: At implant, the VAD cohort was INTERMACS Profile 1 in 33 (23%), Profile 2 in 89 (63%) and Profile 3 in 14 (10%) patients. The VAD cohort was older, larger, and less likely to have congenital heart disease (p < 0.0001). However, they had greater requirements for inotrope and ventilator support and increased liver and renal dysfunction (p < 0.0001), both of which normalized at transplant after device support. Importantly, there were no differences in 1-year post-transplant survival (96% vs 93%, p = 0.3), freedom from infection (81% vs 79%, p = 0.9) or freedom from rejection (71% vs 74%, p = 0.87) between cohorts. CONCLUSIONS: Pediatric VAD patients have post-transplant outcomes equal to that of medically supported patients, despite greater pre-implant illness severity. Post-transplant survival, hospital length of stay, infection and rejection were not affected by patient acuity at VAD implantation or VAD-related complications. Therefore, VAD as bridge to transplant mitigates severity of illness in children.

Second annual Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) report: Pre-implant characteristics and outcomes.

BACKGROUND: Expanded use of pediatric ventricular assist devices (VADs) has decreased mortality in children awaiting heart transplantation. Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), a National Heart, Lung, and Blood Institute-sponsored North American database, provides a platform to understand this emerging population. METHODS: Between September 2012 and September 2016, patients aged younger than 19 years who underwent VAD implantation were enrolled in Pedimacs. FDA approved durable devices as well as temporary support devices were included. The second annual report updates the current Pedimacs data. Patients implanted with temporary devices are included in Pedimacs and this analysis includes this group of paracorporeal continuous flow VADs. RESULTS: Over the 4 years, 42 hospitals implanted 432 devices in 364 patients less than 19 yrs of age. Diagnoses included cardiomyopathy in 223 (61%), myocarditis in 41 (11%), and congenital heart disease in 77 (21%), of which 48 had single-ventricle physiology. At implant, 87% were at Intermacs patient profile 1 or 2. The age distribution of children (59% male) supported on VAD included 69 (19%) aged younger than 1 year, 66 (18%) aged 1 to 6 years, 56 (15%) aged 6 to 10 years, and 173 (48%) aged 11 to 19 years. Median follow-up was 2.2 months (range, 1 day to 41.5 months). Median (interquartile) age at implant was 1.7 (0.3-10.0) years for paracorporeal continuous-flow pumps (n = 60), 1.7 (0.4-5.3) years for paracorporeal pulsatile pumps (n = 105), and 15.0 (11.3-16.9) years for implantable continuous-flow pumps (n = 174). Support strategies included LVAD in 293 (80%), biventricular device in 55 (15%), and total artificial heart in 8 (2%). Nearly 50% of patients underwent transplantation within 6 months, with overall mortality of 19%. Adverse event burden continues to be high. CONCLUSIONS: Pedimacs constitutes the largest longitudinal pediatric VAD registry. Preimplant data across centers will be helpful at creating shared protocols with which to improve outcomes. Adverse events continue to be the major challenge, especially among the young critically ill children with complex congenital disease.

Use of a highly sensitive assay for cardiac troponin T and N-terminal pro-brain natriuretic peptide to diagnose acute rejection in pediatric cardiac transplant recipients.

BACKGROUND: Biomarkers have been proposed to augment or replace endomyocardial biopsy (EMB) to diagnose acute transplant rejection (AR). A new, highly sensitive assay for troponin T detects levels of cardiac troponin T (cTnT) 10- to 100-fold lower than standard assays but has not been investigated in transplant patients. N-terminal pro-brain natriuretic peptide (NT-proBNP) has not been evaluated in pediatric transplant patients. The purpose of this pilot study was to evaluate the association of cTnT and NT-proBNP with AR in pediatric cardiac transplant patients. METHODS: Plasma was obtained at the time of EMB from pediatric patients ≥ 1 year old. N-terminal pro-brain natriuretic peptide was measured in fresh plasma at the time of biopsy, and cTnT was measured from frozen, stored samples using the highly sensitive assay for troponin T. Biomarker data were correlated with EMB results. Cellular AR was defined as an International Society for Heart and Lung Transplantation biopsy score of grade ≥ 2R. RESULTS: Fifty-three blood samples were obtained from 42 patients (mean age 11 years). Seven episodes of AR occurred in 5 patients. Biopsies with vs without AR were associated with higher cTnT (median [interquartile range {IQR}] 66 [45-139] vs 7 [2-13] pg/mL, P = .001) and NT-proBNP (median [IQR] 11,169 [280-23,317] vs 334 [160-650] pg/mL, P < .01). After successful treatment of AR in 5 patients, cTnT fell markedly (median [IQR] 53.5 [44.8-66.5] to 10.7 [1.5-16.4], P = .05). CONCLUSION: In this pilot study, we found marked elevation of cTnT and NT-proBNP among children with AR. Moreover, reduction in cTnT levels after treatment paralleled improvement in EMB results. If these findings are confirmed in larger prospective studies, monitoring with these biomarkers may obviate surveillance EMB.