The Use of Impella 5.5 Reduces Pulmonary Vascular Resistance as Bridge to Heart Transplant in a Pediatric Patient.

This case report explores the successful use of the Impella 5.5 (Abiomed Inc., Danvers, MA) device in a 22 kg, 0.89 body surface area (BSA) pediatric patient with longstanding dilated cardiomyopathy and elevated pulmonary vascular resistance. The article details the device selection, management, and outcome demonstrating the feasibility and potential benefits of the Impella 5.5 as a device within the pediatric population.

Outcomes Of Heart Transplantation In Children With Previously Palliated Hypoplastic Left Heart Syndrome.

OBJECTIVES: Paediatric heart transplantation in children who fail multistage palliation for hypoplastic left heart syndrome is associated with challenges related to immune, clinical, or anatomic risk factors. We review current outcomes and risk factors for survival following heart transplantation in this challenging patient population. METHODS: The United Network for Organ Sharing transplantation database was merged with Paediatric Health Information System database to identify children who received heart transplantation following prior palliation for hypoplastic left heart syndrome. Multivariable Cox analysis of outcomes and factors affecting survival was performed. RESULTS: Our cohort included 849 children between 2009-21. Median age was 1044 days (interquartile range 108-3535) and median weight was 13 kg (interquartile range 7-26). Overall survival at 10 years following heart transplantation was 71%, with the majority of death being peri-operative. On multivariable analysis, risk factors for survival included black race (HR = 1.630, p = 0.0253), blood type other than B (HR = 2.564, p = 0.0052), and male donor gender (HR = 1.367, p = 0.0483). Recipient age, the use of ventricular assist device or extracorporeal membrane oxygenation were not significantly associated with survival. 24 patients underwent retransplantation and 10-year freedom from retransplantation was 98%. Rejection prior to hospital discharge and within one year from transplantation was 20% and 24%, respectively, with infants having lower rejection rates. CONCLUSIONS: Compared to existing literature, the number of children with prior hypoplastic left heart syndrome palliation who receive heart transplantation has increased in the current era. Survival following transplantation in this patient population is acceptable. The majority of death is perioperative. Efforts to properly support these patients prior to transplantation might decrease early mortality and improve overall survival.

Trends and outcomes of heart transplantation in adults with congenital heart disease.

OBJECTIVES: Heart transplantation for adult congenital heart disease is complicated and associated with challenging pretransplant support, long waiting and high early post-transplant mortality. We explored if surgical and medical advances and allocation system changes have affected outcomes. METHODS: From United Network for Organ Sharing database, adults with congenital heart disease listed for heart transplantation were queried. To explore practice and outcome trends, patients were divided into 4 eras (eras 1-3: nearly 3 equal periods from 1992 to 2018, era 4: after 2018, corresponding with new allocation system). Univariate and multivariable analysis was performed to evaluate outcomes. RESULTS: A total of 2737 patients were listed. There was gradual increase in listed and transplanted patients, along with significant increase in use of mechanical support, simultaneous kidney and liver transplantation. While proportion of transplanted remained constant, there was decrease in proportion delisted/died after listing (P = 0.01) and waiting list duration (P = 0.01), especially in era 4. Thirty-day post-transplant mortality remains high; however, it has significantly improved starting era 3 (P = 0.01). Current survival at 1-year and 5-years is 85% and 65%, with improvement mainly related to decreased early death. On multivariable analysis, factors associated with survival were lower glomerular filtration rate (hazard ratio = 0.99, P = 0.042), bilirubin (hazard ratio = 1.17, P<0.001) and mechanical ventilation (hazard ratio = 2.3, P=0.004). CONCLUSIONS: Heart transplantation in adults with congenital heart disease is increasing, along with added complexity, higher usage of pretransplant mechanical support and simultaneous organ transplantation. Despite that, more complex patients do not experience worse outcomes. Early mortality improved but remains high. New donor allocation system allowed shorter waiting time and higher proportion transplanted without altering early mortality.

Associated Factors and Impact of Persistent Renal Dysfunction in Pediatric Heart Transplantation.

BACKGROUND: We evaluated the impact of significant renal dysfunction (SRD) on listing and pediatric heart transplantation (PHT) outcomes. METHODS: The United Network of Organ Sharing registry was queried. Our cohort included 11,625 children listed for PHT (2000-2020). At listing, 1494 (13%) had SRD, defined as an estimated glomerular filtration rate of <45 mL/min/1.73 m2 and/or dialysis requirement. Characteristics of children with and without SRD were compared. SRD impact on outcomes was examined. Factors associated with waiting list mortality, persistent SRD at PHT, and post-PHT survival with and without simultaneous heart-kidney transplantation were assessed. RESULTS: Compared with children with an estimated glomerular filtration rate >45 mL/min/1.73 m2, those with SRD had higher waiting list death (37% vs 14%, P < .01) and lower transplantation rate (51% vs 71%, P < .01). On multivariable analysis, SRD was associated with waiting list death (hazard ratio, 3.016; P < .0001). Among 767 children with SRD who received PHT, 361 (47%) had persistent SRD at the time of PHT. On multivariable analysis, factors associated with persistent SRD were older age (odds ratio [OR], 1.147 per year; 95% CI, 1.046-1.258 per year; P = .0035), bilirubin (OR, 1.127 per 1-mg/dL; 95% CI, 1.061-1.197 per 1-mg/dL; P < .0001), dialysis (OR, 1.839; 95% CI, 1.017-3.326; P = .0115), mechanical ventilation (OR, 1.972; 95% CI, 1.336-2.911; P = .0006), extracorporeal membrane oxygenation (OR, 1.747; 95% CI, 1.074-2.842; P = .0247), and not using a ventricular assist device (VAD) (OR, 0.498 [VAD use]; 95% CI, 0.277-0.895 VAD use; P = .0198). Post-PHT survival was 72%, 70%, and 56% (P < .01) at 8 years for PHT alone with improved renal function, simultaneous heart-kidney transplantation (n = 69), and PHT alone with persistent SRD, respectively. CONCLUSIONS: SRD is associated with high waiting list death and decreased transplantation rate. Timely proper pre-PHT support with VAD could enhance kidney recovery. Simultaneous heart-kidney transplantation neutralized persistent SRD effect on survival and might be considered in high-risk patients such as those on dialysis, mechanical ventilation, or extracorporeal membrane oxygenation support.

Increasing donor-recipient weight mismatch in infant heart transplantation is associated with shorter waitlist duration and no increased morbidity or mortality.

OBJECTIVES: Infants awaiting paediatric heart transplantation (PHT) experience long waitlist duration and high mortality due to donor shortage. Using the United Network for Organ Sharing database, we explored if increasing donor-recipient weight ratio (DRWR) >2.0 (recommended cutoff) was associated with adverse outcomes. METHODS: Between 2007 and 2020, 1392 infants received PHT. We divided cohort into 3 groups: A (DRWR ≤1.0, n = 239, 17%), B (DRWR 1.0-2.0, n = 947, 68%), C (DRWR >2.0, n = 206, 15%). Group characteristics and PHT outcomes were analysed. RESULTS: DRWR ranged between 0.5 and 4.1. Underlying pathology (congenital versus cardiomyopathy), gender, race, renal function and mechanical circulatory support were comparable between groups. Group C patients were more likely to be ventilated, to receive ABO blood group (ABO)-incompatible heart and to have longer donor ischaemic time. Waitlist duration was significantly shorter for group C (33 vs 50 days, P < 0.1). Early outcomes for groups A, B and C were the following (respectively): operative death (6%, 4%, 3%, P = 0.29), primary graft dysfunction (5%, 3%, 3%, P = 0.30), renal failure (10%, 7%, 7%, P = 0.42) and stroke (3%, 4%, 1%, P = 0.36). The DRWR group was not associated with operative death in either congenital (odds ratio (OR) = 0.819, 95% confidence interval (CI) = 0.523-1.282) or cardiomyopathy (OR = 1.221, 95% CI = 0.780-1.912) patients and only significant factor was pre-PHT extracorporeal membrane oxygenation (OR = 4.400, 95% CI = 2.761-7.010). Additionally, survival at 1 year (87%, 87%, 85%, P = 0.80) and 5 years (76%, 78%, 77%, P = 0.80) was comparable between the DRWR groups. CONCLUSIONS: Infants who received PHT with DRWR >2.0, up to 4.1, experienced shorter waitlist duration with no demonstrable increase in peri-transplant complications, operative or late mortality. Historic practice to avoid DRWR > 2.0 due to complications (e.g. hypertension-related stroke, graft dysfunction, death) is not currently supported in infants and stretching DRWR acceptance criteria would decrease PHT waitlist duration and potentially improve waitlist complications and mortality.

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.

Cardiovascular health in pediatric heart transplant patients.

BACKGROUND: Ideal "cardiovascular health" (CVH)-optimal diet, exercise, nonsmoking, BMI, BP, lipids, and glucose-is associated with healthy longevity in adults. Pediatric heart transplant (HT) patients may be at risk for suboptimal CVH. METHODS: Single-center retrospective study of HT patients 2003-2014 who survived 1 year post-transplant. Five CVH metrics were collected at listing, 1, 3 and 5 years post-transplant (diet and exercise were unavailable). CVH was scored by summing individual metrics: ideal = 2, intermediate = 1, and poor = 0 points; total scores of 8-10 points were considered high (favorable). CVH was compared between HT patients and the US pediatric population (GP) utilizing NHANES 2007-2016. Logistic regression was performed to examine the association of CVH 1 year post-transplant with a composite adverse outcome (death, re-listing, coronary vasculopathy, or chronic kidney disease) 3 years post-transplant. RESULTS: We included 110 HT patients (median age at HT: 6 years [range 0.1-21]) and 19,081 NHANES participants. CVH scores among HT patients were generally high at listing (75%), 1 (74%), 3 (87%) and 5 (76%) years post-transplant and similar to GP, but some metrics (e.g., glucose) were worse among HT patients. Among HT patients, CVH was poorer with older age and non-Caucasian race/ethnicity. Per 1-point higher CVH score, the demographic-adjusted OR for adverse outcomes was 0.95 (95% CI, 0.7-1.4). CONCLUSIONS: HT patients had generally favorable CVH, but some metrics were unfavorable and CVH varied by age and race/ethnicity. No significant association was detected between CVH and adverse outcomes in this small sample, but study in a larger sample is warranted.

Modified Microvascular Plug as a Flow Restrictor in Hypoplastic Left Heart Syndrome with Dysplastic Tricuspid and Pulmonary Valves.

While the Norwood operation is the most common palliative surgery for neonates with hypoplastic left heart syndrome (HLHS), initial hybrid strategy aiming to restrict pulmonary blood flow and maintain systemic output is necessary when Norwood is contraindicated or at high risk. The traditional mainstay of initial hybrid palliation is surgical pulmonary artery branch banding (PABB) plus interventional ductal stenting. We present a case of a transcatheter approach for pulmonary flow restriction (PFR) that was accomplished by modifying a Medtronic microvascular plug (MVP)™. The patient is a 2.4 kg neonate diagnosed with HLHS, dysplastic tricuspid and pulmonary valves with pulmonary stenosis, tricuspid stenosis, and regurgitation. He was not considered a candidate for surgical intervention. He started developing sequelae of unbalanced pulmonary and systemic blood flow; therefore, he underwent placement of transcatheter PFR as alternative to PABB. He underwent successful orthotopic heart transplant 104 days after index procedure. This case demonstrates the significant complexity that can occur in patients with HLHS and abnormal right sided valves. Additionally, it is another example that transcatheter branch pulmonary artery flow restriction can be a safe and feasible alternative to PABB as initial palliation strategy. It may benefit patients in whom primary Norwood procedure would have increased risks or who will undergo primary transplant.

Pediatric waitlist and heart transplant outcomes in patients with syndromic anomalies.

PURPOSE: We sought to determine whether the presence of a systemic SA with potential complicating factors affects waitlist and post-HT outcomes in pediatric patients. METHODS: This is a single-center retrospective review of pediatric patients listed for HT between January 1, 2009, and July 1, 2018. Patients were selected based on the presence of any underlying syndromes, which included chromosomal anomalies, skeletal myopathies, connective tissue disorders, mitochondrial disease,and other systemic disorders. Waitlist and post-HT outcomes were compared to those without SA. RESULTS: A total of 243 patients were listed for HT, of which 21 (9%) patients had associated SA. Of those, 16 (76%) survived to transplant, 3 (14%) died while on the waitlist, 1 (5%) improved and was removed from the waitlist, and 1 (5%) patient is currently listed. Waitlist survival was not different between those with/without an associated syndrome (P = 1.0). Among those who survived to HT, there was no difference in listing days (70 vs 90, P = .8), survival to hospital discharge [14 (93%) vs 150 (95%), P = .6], post-HT intubation days (2 vs 2 days, P = .6), or post-HT hospital length of stay (18 vs 18 days, P = .8). Overall survival during the study period post-HT was not different between groups (P = .8). CONCLUSION: A SA was present in 9% of pediatric patients wait-listed for HT, but was not associated with an increased waitlist mortality or post-HT hospital morbidity or long-term survival. For several anomalies, HT is safe and feasible.