Mechanical Ventilation and Outcomes of Children Who Undergo Ventricular Assist Device Placement: 2014-2020 Linked Analysis From the Advanced Cardiac Therapies Improving Outcomes Network and Pediatric Cardiac Critical Care Consortium Registries.

OBJECTIVES: Placement of a ventricular assist device (VAD) improves outcomes in children with advanced heart failure, but adverse events remain important consequences. Preoperative mechanical ventilation (MV) increases mortality, but it is unknown what impact prolonged postoperative MV has. DESIGN: Advanced Cardiac Therapies Improving Outcomes Network (ACTION) and Pediatric Cardiac Critical Care Consortium (PC4) registries were used to identify and link children with initial VAD placement admitted to the cardiac ICU (CICU) from August 2014 to July 2020. Demographics, cardiac diagnosis, preoperative and postoperative CICU courses, and outcomes were compiled. Univariable and multivariable statistics assessed association of patient factors with prolonged postoperative MV. Multivariable logistic regression sought independent associations with outcomes. SETTING: Thirty-five pediatric CICUs across the United States and Canada. PATIENTS: Children on VADs included in both registries. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two hundred forty-eight ACTION subjects were linked to a matching patient in PC4. Median (interquartile) age 7.7 years (1.5-15.5 yr), weight 21.3 kg (9.1-58 kg), and 56% male. Primary diagnosis was congenital heart disease (CHD) in 35%. Pre-VAD explanatory variables independently associated with prolonged postoperative MV included: age (incidence rate ratio [IRR], 0.95; 95% CI, 0.93-0.96; p < 0.01); preoperative MV within 48 hours (IRR, 2.76; 95% CI, 1.59-4.79; p < 0.01), 2-7 days (IRR, 1.82; 95% CI, 1.15-2.89; p = 0.011), and greater than 7 days before VAD implant (IRR, 2.35; 95% CI, 1.62-3.4; p < 0.01); and CHD (IRR, 1.96; 95% CI, 1.48-2.59; p < 0.01). Each additional day of postoperative MV was associated with greater odds of mortality (odds ratio [OR], 1.09 per day; p < 0.01) in the full cohort. We identified an associated greater odds of mortality in the 102 patients with intracorporeal devices (OR, 1.24; 95% CI, 1.04-1.48; p = 0.014), but not paracorporeal devices (77 patients; OR, 1.04; 95% CI, 0.99-1.09; p = 0.115). CONCLUSIONS: Prolonged MV after VAD placement is associated with greater odds of mortality in intracorporeal devices, which may indicate inadequacy of cardiopulmonary support in this group. This linkage provides a platform for future analyses in this population.

Achieving Consensus: Severity-Graded Definitions of Fontan-Associated Complications to Characterize Fontan Circulatory Failure.

BACKGROUND: Fontan physiology leads to chronic changes in other organ systems that may affect long-term survival and the success of heart transplantation. Inadequate assessment and treatment of the extra-cardiac effects of Fontan may contribute to poor outcomes. Severity-graded/ordinal consensus definitions of Fontan complications are lacking, which limits understanding of how Fontan-specific morbidity affects patients' outcomes. METHODS AND RESULTS: A panel of Fontan patient and physiology experts, including pediatric, adult congenital, heart failure, and critical-care cardiology as well as pediatric nephrology, hepatology and psychology, convened to develop definitions of Fontan complications. Definitions were created by using a severity-graded ordinal scale: grade 1, mild; grade 2, moderate; grade 3, severe; grade 4, disabling or life threatening. Following definition creation, a second panel of 21 experts in Fontan circulatory failure used a modified Delphi methodology to modify and vote on definitions until consensus (> 90% agreement without recommended further modification) was reached on final definitions. After 3 rounds of modifications and voting, consensus agreement was achieved on all Fontan-specific definitions. The defined complications and morbidities of Fontan include: anatomic Fontan pathway obstruction, cyanosis, systemic venous abnormalities resulting from venous insufficiency, atrial arrhythmia, ventricular arrhythmia, bradycardia, chronic pleural effusions, chronic ascites, protein-losing enteropathy, plastic bronchitis, hemoptysis and pulmonary hemorrhage, sleep apnea, Fontan-associated liver disease, portal and hepatic variceal disease, acute kidney injury affecting clinical treatment, polycythemia, thrombotic disease, recurrent or severe bacterial infection, skin atrophy, adrenal insufficiency, physical impact of previous stroke, mood/behavior disorder, and neurodevelopmental disorder. CONCLUSION: Consensus and severity-graded definitions of Fontan-specific cardiac and extra-cardiac complications were achieved and are available for use in research. They will allow future robust analyses of Fontan patient outcomes.

Multicenter Study of Survival Benefit of Cardiac Resynchronization Therapy in Pediatric and Congenital Heart Disease.

BACKGROUND: Evidence for the efficacy of cardiac resynchronization therapy (CRT) in pediatric and congenital heart disease (CHD) has been limited to surrogate outcomes. OBJECTIVES: This study aimed to assess the impact of CRT upon the risk of transplantation or death in a retrospective, high-risk, controlled cohort at 5 quaternary referral centers. METHODS: Both CRT patients and control patients were <21 years of age or had CHD; had systemic ventricular ejection fraction <45%; symptomatic heart failure; and significant electrical dyssynchrony (QRS duration z score >3 or single-site ventricular pacing >40%) at enrollment. Patients with CRT were matched with control patients via 1:1 propensity score matching. CRT patients were enrolled at CRT implantation; control patients were enrolled at the outpatient clinical encounter where inclusion criteria were first met. The primary endpoint was transplantation or death. RESULTS: In total, 324 control patients and 167 CRT recipients were identified. Mean follow-up was 4.2 ± 3.7 years. Upon propensity score matching, 139 closely matched pairs were identified (20 baseline indices). Of the 139 matched pairs, 52 (37.0%) control patients and 31 (22.0%) CRT recipients reached the primary endpoint. On both unadjusted and multivariable Cox regression analysis, the risk reduction associated with CRT for the primary endpoint was significant (HR: 0.40; 95% CI: 0.25-0.64; P < 0.001; and HR: 0.44; 95% CI: 0.28-0.71; P = 0.001, respectively). On longitudinal assessment, the CRT group had significantly improved systemic ventricular ejection fraction (P < 0.001) and shorter QRS duration (P = 0.015), sustained to 5 years. CONCLUSIONS: In pediatric and CHD patients with symptomatic systolic heart failure and electrical dyssynchrony, CRT was associated with improved heart transplantation-free survival.

Reducing donor acceptance practice variation - Learnings from a discussion forum.

PURPOSE: Although waitlist mortality is unacceptably high, nearly half of donor heart offers are rejected by pediatric heart transplant centers. The Advanced Cardiac Therapy Improving Outcome Network (ACTION) and Pediatric Heart Transplant Society (PHTS) convened a multi-institutional donor decision discussion forum (DDDF) aimed at assessing donor acceptance practices and reducing practice variation. METHODS: A 1-h-long virtual DDDF for providers across North America, the United Kingdom, and Brazil was held monthly. Each session typically included two case presentations posing a real-world donor decision challenge. Attendees were polled before the presenting center's decision was revealed. Group discussion followed, including a review of relevant literature and PHTS data. Metrics of participation, participant agreement with presenting center decisions, and impact on future decision-making were collected and analyzed. RESULTS: Over 2 years, 41 cases were discussed. Approximately 50 clinicians attended each call. Risk factors influencing decision-making included donor quality (10), size discrepancy (8), and COVID-19 (8). Donor characteristics influenced 63% of decisions, recipient factors 35%. Participants agreed with the decision made by the presenting center only 49% of the time. Post-presentation discussion resulted in 25% of participants changing their original decision. Survey conducted reported that 50% respondents changed their donor acceptance practices. CONCLUSION: DDDF identified significant variation in pediatric donor decision-making among centers. DDDF may be an effective format to reduce practice variation, provide education to decision-makers, and ultimately increase donor utilization.

Successful implementation of telehealth visits in the paediatric heart failure and heart transplant population.

The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) and Pediatric Heart Transplant Society (PHTS) convened a working group at the beginning of 2020 during the COVID-19 pandemic, with the aim of using telehealth as an alternative medium to provide quality care to a high-acuity paediatric population receiving advanced cardiac therapies. An algorithm was developed to determine appropriateness, educational handouts were developed for both patients and providers, and post-visit surveys were collected. Telehealth was found to be a viable modality for health care delivery in the paediatric heart failure and transplant population and has promising application in the continuity of follow-up, medication titration, and patient education/counselling domains.

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.

Widening care gap in VAD therapy.

BACKGROUND: The removal of the HeartWare ventricular assist device (HVAD) due to pump malfunctions and inferior outcomes compared to HeartMate 3 (HM3) in adults has created a care gap for younger patients. It is unclear if the reported HVAD survival differs by age and if the initial experience with HM3 can bridge the gap. METHODS: Using the Society of Thoracic Surgeons (STS) Intermacs and Pedimacs registries, durable ventricular assist device (VAD) implants between September 2012 and December 2021 were identified. Young adults (YA) were defined as <40 years old in Intermacs. Patients were excluded if they had an isolated right VAD (RVAD) or were implanted as destination therapy (DT). Survival analysis by Kaplan-Meier (KM) and competing outcomes curves was performed, and 1-year survival is reported. RESULTS: The Intermacs cohort consisted of YA (n = 1226; HVAD 818; HM3 408) with a median age of YA of 32.07 (26.66-36.27) years and weight (wt) of 83.2 (68-104.2) kg. Most had cardiomyopathy (CM) (92.2%). The Pedimacs cohort was 668 patients (median age 9.47 [1.82-14.23] years, wt 27.2 [10-57.05] kg), and most also had CM (70.5%). Device breakdown included HVAD (n = 326), Berlin EXCOR (n = 277), and HM3 (n = 65). HVAD survival differed by age in adults, with YA fairing better than adults >40 years old (88.8% vs 79.4% at 1 year, p < 0.0001). YA survival was also better compared to Pedimacs patient (88.9% vs 83.7%, p = 0.0002), but when competing events were analyzed, mortality was similar to YA (9.2% vs 9.6%, p = 0.1) with a higher proportion of patient undergoing transplant at 1 year in Pedimacs (74% vs 31.3%, p < 0.0001). Survival by device differed between HVAD and HM3 in YA (88.8% vs 94.4%, p = 0.0025). This difference in device survival was not seen in all children (83.7% vs 87.3%, p = 0.21), including those ≥25 kg. Adverse event profiles also differed across the groups with adults seeing less adverse events with the HM3, but the same was not found (including stroke) in the pediatric cohort. Survival outcomes for patients between 10 and 25 kg were similar with the HVAD compared to the Berlin Heart EXCOR (p = 0.4290), with similarities in stroke risk. CONCLUSION: The removal of the HVAD device may result in a care gap in younger patient whose survival outcomes do not mirror that of older adults. The HM3 can fill a portion of this gap with good survival, but there remains a subset of pediatric patients that, based on initial HM3 use, will no longer have access to intracorporeal support and therefore, despite reasonable outcomes with the Berlin Heart EXCOR, will not be able to be discharged home. Lastly, it is essential that future changes to the availability of devices take into account the various patient populations that utilize the device to avoid unintended consequences of access inequality.

Differences in Quality of Life in Children Across the Spectrum of Congenital Heart Disease.

OBJECTIVE: To create complexity groups based upon a patient's cardiac medical history and to test for group differences in health-related quality of life (HRQOL). METHODS: Patients 8-18 years with congenital heart disease (CHD) and parent-proxies from the Pediatric Cardiac Quality of Life Inventory (PCQLI) Testing Study were included. Outcome variables included PCQLI Total, Disease Impact, and Psychosocial Impact scores. Using a patient's medical history (cardiac, neurologic, psychological, and cognitive diagnosis), latent class analysis (LCA) was used to create CHD complexity groups. Covariates included demographics and burden of illness (number of: school weeks missed, physician visits in the past year, and daily medications). Generalized estimation equations tested for differences in burden of illness and patient and parent-proxy PCQLI scores. RESULTS: Using 1482 CHD patients (60% male; 84% white; age 12.3 ± 3.0 years), latent class analysis (LCA) estimates showed 4 distinct CHD complexity groups (Mild, Moderate 1, Moderate 2, and Severe). Increasing CHD complexity was associated with increased risk of learning disorders, seizures, mental health problems, and history of stroke. Greater CHD complexity was associated with greater burden of illness (P < .01) and lower patient- and parent-reported PCQLI scores (P < .001). CONCLUSIONS: LCA identified 4 congenital heart disease (CHD) complexity groupings. Increasing CHD complexity was associated with higher burden of illness and worse patient- and parent-reported HRQOL.

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.

Taking ACTION: A Prognostic Tool for Pediatric Ventricular Assist Device Mortality.

We sought to develop a contemporary risk assessment tool for use in pediatric ventricular assist device (VAD) candidates to estimate risk for mortality on the device using readily available preimplantation clinical data. Training and testing datasets were created from Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry data on patients supported with a VAD from 2012 to 2021. Potential risk factors for mortality were assessed and incorporated into a simplified risk prediction model utilizing an open-source, gradient-boosted decision tree machine learning library, known as random forest. Predictive performance was assessed by the area under the receiver operating characteristic curve in the testing dataset. Nine significant risk factors were included in the final predictive model which demonstrated excellent discrimination with an area under the curve of 0.95. In addition to providing a framework for establishing pediatric-specific risk profiles, our model can help inform team expectations, guide optimal patient selection, and ultimately improve patient outcomes.

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.

Patient and parent-reported outcomes in paediatric ventricular assist device support: a multi-center ACTION learning network feasibility and pilot experience.

BACKGROUND: Patient- and proxy-reported outcomes (PROs) are an important indicator of healthcare quality and can be used to inform treatment. Despite the widescale use of PROs in adult cardiology, they are underutilised in paediatric cardiac care. This study describes a six-center feasibility and pilot experience implementing PROs in the paediatric and young adult ventricular assist device population. METHODS: The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) is a collaborative learning network comprised of 55 centres focused on improving clinical outcomes and the patient/family experience for children with heart failure and those supported by ventricular assist devices. The development of ACTION's PRO programme via engagement with patient and parent stakeholders is described. Pilot feasibility, patient/parent and clinician feedback, and initial PRO findings of patients and families receiving paediatric ventricular assist support across six centres are detailed. RESULTS: Thirty of the thirty-five eligible patients (85.7%) were enrolled in the PRO programme during the pilot study period. Clinicians and participating patients/parents reported positive experiences with the PRO pilot programme. The most common symptoms reported by patients/parents in the first month post-implant period included limitations in activities, dressing change distress, and post-operative pain. Poor sleep, dressing change distress, sadness, and fatigue were the most common symptoms endorsed >30 days post-implant. Parental sadness and worry were notable throughout the entirety of the post-implant experience. CONCLUSIONS: This multi-center ACTION learning network-based PRO programme demonstrated initial success in this six-center pilot study experience and yields important next steps for larger-scale PRO collection, research, and clinical intervention.

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.

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.

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.

Global best practices consensus: Long-term management of patients with hybrid centrifugal flow left ventricular assist device support.

OBJECTIVES: Six months after withdrawal of the HeartWare HVAD System (HVAD; Medtronic) from sale, approximately 4000 patients continue ongoing support with this device. In light of the diminishing experience, this global consensus document summarizes key management recommendations. METHODS: International experts with experience in the management of patients with ongoing HVAD support were invited to summarize key aspects of patient and pump management and highlight differences in the current HeartMate 3 (Abbott Laboratories) ventricular assist device. Clinicians from high-implanting HVAD sites reviewed current literature and reported experience to generate a consensus statement. RESULTS: Specific guidelines to assist in the management of ongoing HVAD patients are developed. Key management protocols and helpful techniques developed from experienced clinicians are combined into a short guideline document. As experience with HeartMate 3 increases, key differences in approach to management are highlighted, where appropriate. CONCLUSIONS: With decreasing worldwide experience in the ongoing management of HVAD-supported patients, this consensus guideline provides a summary of best practice techniques from international centers. Differences in HeartMate 3 management are highlighted.

Decreased Risk of Strokes in Children with Ventricular Assist Devices Within ACTION.

We sought to characterize strokes in children with ventricular assist devices. Of 407 patients in the ACTION registry (4/1/18-5/3/2021), 45 (11%) experienced 52 strokes (45 ischemic and 7 hemorrhagic). Median time to stroke was 23.5 days and 19/52 (37%) occurred ≤ 10 days. Stroke rate was 0.09 and 0.63 strokes per patient-year for implantable continuous and paracorporeal devices, respectively. Patients with stroke were younger, more likely to have congenital heart disease and have been on extracorporeal membrane oxygenation at time of VAD. Based on these data, ACTION is now focused on decreasing strokes in these higher-risk patients with particular attention to the peri-implant period.

A Mechanistic Lumped Parameter Model of the Berlin Heart EXCOR to Analyze Device Performance and Physiologic Interactions.

PURPOSE: The Berlin Heart EXCOR (BH) is the only FDA-approved, extracorporeal pulsatile ventricular assist device (VAD) for infants and children with heart failure. Clinicians control four settings on the device-systolic and diastolic drive pressures, device pump rate, and systolic time as a percentage of the pump cycle. However, interactions between BH pneumatics and the native circulation remain poorly understood. Thus, establishing appropriate device size and settings can be challenging on a patient-to-patient basis. METHODS: In this study we develop a novel lumped parameter network based on simplified device mechanics. We perform parametric studies to characterize device behavior, study interactions between the left ventricle (LV) and BH across different device settings, and develop patient-specific simulations. We then simulate the impact of changing device parameters for each of three patients. RESULTS: Increasing systolic pressure and systolic time increased device output. We identified previously unobserved cycle-to-cycle variations in LV-BH interactions that may impact patient health. Patient-specific simulations demonstrated the model's ability to replicate BH performance, captured trends in LV behavior after device implantation, and emphasized the importance of device rate and volume in optimizing BH efficiency. CONCLUSION: We present a novel, mechanistic model that can be readily adjusted to study a wide range of device settings and clinical scenarios. Physiologic interactions between the BH and the native LV produced large variability in cardiac loading. Our findings showed that operating the BH at a device rate greater than the patient's native heart decreases variability in physiological interactions between the BH and LV, increasing cardiac offloading while maintaining cardiac output. Device rates that are close to the resting heart rate may result in unfavorable cardiac loading conditions. Our work demonstrates the utility of our model to investigate BH performance for patient-specific physiologies.

Adverse Events Associated with Cardiac Catheterization in Children Supported with Ventricular Assist Devices.

Children on ventricular assist device (VAD) support can present several unique challenges, including small patient size, univentricular or biventricular congenital heart disease (1V- or 2V-CHD) and need for biventricular VAD (BiVAD) support. While cardiac catheterization can provide valuable information, it is an invasive procedure with inherent risks. We sought to evaluate the safety of catheterization in pediatric patients on VAD support. We performed a retrospective review of patients on VAD support who underwent catheterization at Lucile Packard Children's Hospital between January 1, 2014 and September 1, 2019. Using definitions adapted from Pedimacs, adverse events (AEs) after catheterization were identified, including arrhythmia; major bleeding or acute kidney injury within 24 hours; respiratory failure persisting at 24 hours; and stroke, pericardial effusion, device malfunction, bacteremia or death within 7 days. AEs were categorized as related or unrelated to catheterization. Sixty procedures were performed on 39 patients. Underlying diagnoses were dilated cardiomyopathy (48%), 1V-CHD (35%), 2V-CHD (8%), and other (8%). Devices were implantable continuous flow (72%), paracorporeal pulsatile (18%) and paracorporeal continuous flow (10%). Catheterizations were performed on patients in the ICU (60%), on inotropic support (42%), with deteriorating clinical status (37%) and on BiVAD support (12%). There were 9 AEs possibly related to catheterization including 6 episodes of respiratory failure, 2 major bleeding events, and 1 procedural arrhythmia. AE occurrence was associated with ICU status ( P = 0.01), BiVAD support ( P = 0.04) and procedural indication to evaluate worsening clinical status ( P = 0.04). Despite high medical acuity, catheterization can be performed with an acceptable AE profile in children on VAD support.

Hemodynamic Predictors of Renal Function After Pediatric Left Ventricular Assist Device Implantation.

Although renal function often improves after pediatric left ventricular assist device (LVAD) implantation, recovery is inconsistent. We aimed to identify hemodynamic parameters associated with improved renal function after pediatric LVAD placement. A single-center retrospective cohort study was conducted in patients less than 21 years who underwent LVAD placement between June 2004 and December 2015. The relationship between hemodynamic parameters and estimated glomerular filtration rate (eGFR) was assessed using univariate and multivariate modeling. Among 54 patients, higher preoperative central venous pressure (CVP) was associated with eGFR improvement after implantation (p = 0.012). However, 48 hours postimplantation, an increase in CVP from baseline was associated with eGFR decline over time (p = 0.01). In subgroup analysis, these associations were significant only for those with normal pre-ventricular assist device renal function (p = 0.026). In patients with preexisting renal dysfunction, higher absolute CVP values 48 and 72 hours after implantation predicted better renal outcome (p = 0.005). Our results illustrate a complex relationship between ventricular function, volume status, and renal function. Additionally, they highlight the challenge of using CVP to guide management of renal dysfunction in pediatric heart failure. Better methods for evaluating right heart function and volume status are needed to improve our understanding of how hemodynamics impact renal function in this population.