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While combined heart-liver transplant (HLT) is being performed for Fontan patients, outcomes and indications remain poorly defined. We compared listing characteristics and post-transplant outcomes of Fontan patients with HLT to those with heart-only transplant (HT). We retrospectively reviewed all Fontan patients undergoing HT or HLT at our institution between 2006-2019. Pre-transplant liver disease at the time of listing, as determined by laboratory and radiology data, and MELD-XI, Child Pugh, and VAST scores, were compared between groups. The Kaplan Meier survival method was used to compare post-transplant survival and freedom from rejection (ISHLT Grade 2R+ or pAMR2+). Forty-two patients (33 HT, 9 HLT) were included. HLT patients were older, more likely to be on dual-inotrope therapy, had worse Child Pugh and VAST scores, and were more likely to have varices, ascites, splenomegaly, and cirrhosis on imaging (Table 1). While not significant, HLT patients tended to be more sensitized, had higher total bilirubin and creatinine, and lower platelet count. Over a median post-transplant follow-up of 22 (5, 62) months, overall mortality for the entire cohort was 19%; only one HLT patient died (11%) versus 7 (21%) HT patients (p=0.58, Figure 1). None of the HLT patients experienced rejection, whereas 11 (33%) HT patients had rejection (p=0.06). Despite a greater inotrope need and more severe liver disease at time of listing, patients undergoing HLT have post-transplant outcomes that are comparable, if not better, than Fontan patients with HT. There appears to be a protective effect from rejection with HLT. [ABSTRACT FROM AUTHOR]

Infectious complications are a major cause of morbidity & mortality after heart transplantation (HT). Patients who have undergone Fontan palliation may have a higher susceptibility to post HT infections given thymectomy in infancy and known depletions of T-cell subsets. This was a single-center, retrospective cohort analysis of pediatric patients undergoing HT for dilated cardiomyopathy (DCM) or failing Fontan physiology, who underwent post HT induction with anti-thymoglobulin (ATG). Repeat HTs and multi organ transplants were excluded. The primary endpoint was infection in the first 180 days post HT, defined as 1) positive blood, urine, or respiratory culture; 2) positive viral PCR (excluding CMV and EBV); 3) skin or wound infection; or 4) culture-negative infection if a full antibiotic course (≥ 5 days) was completed. Secondary endpoints included sensitivity to ATG as defined by 1) absolute lymphocyte (ALC) and CD3 counts after 5 doses; 2) the incidence of post transplant lymphoproliferative disorder (PTLD); and 3) rejection (>/= Grade 2R ACR or pAMR2) in the first 180 days post HT. From 1/2014 to 9/2019, 63 patients (30 Fontan, 33 DCM) underwent HT at a median of 15.4 (IQR 10.8, 20.1) and 11.7 (IQR 1.4, 13.6) years, respectively. The median total ATG received was 7.5 (IQR 6.7, 8.2) mg/kg vs 7.2 (IQR 4.7, 9.2) mg/kg (p=NS), respectively. The median CD3 [9 (IQR 3,14) vs 12 (IQR 6, 26); p=0.04, Figure 1A ] and lymphocyte counts [172 (IQR 98, 354) vs 427 (IQR 205, 662); p=0.02 ] after ATG were lower in Fontan vs DCM patients. 28 patients (41%) developed at least one infection within 180 days after HT, with a higher rate of infection in Fontan patients (60% vs 24%, p=0.005; Figure 1B). There was no difference in the incidence of PTLD (10% vs 0%; p=0.1) or rejection (17% vs 27%; p=0.31) between Fontan vs DCM patients, respectively. Compared to DCM patients, Fontan patients have a more pronounced suppression of CD3 counts after induction, as well as a higher risk of infection. [ABSTRACT FROM AUTHOR]

Purpose Previous studies have developed validated risk-prediction models for pediatric heart failure (HF). However, ventricular assist device (VAD) use and organ allocation practices have shifted markedly over the last decade for pediatric heart transplant (HT) candidates. We sought to develop and validate a risk-prediction model in a contemporary cohort of pediatric HF patients. Methods Children <18 years of age listed for HT in the US between 2010 and 2014 were identified using OPTN data. 2010 was chosen as the earliest date because model performance declined when earlier-era patients with higher mortality were included. A 30-day mortality risk-prediction model was developed using k-fold cross validation, and independently validated in a cohort of children listed between January 2015 and June 2017. Results The selected predictive model had 5 categorical variables: mechanical support [ECMO (Odds ratio, OR 6.3), VAD support (OR 1.3), vs no support], ventilator support (OR 2.5), cardiac diagnosis [congenital heart disease (CHD) (OR 2.3), vs. cardiomyopathy], renal dysfunction [dysfunction (OR 2.3), vs. normal], and weight categories at listing [25-50 kg (OR 2.0), 10-25 kg (OR 3.2), 5-10 kg (OR 3.7), and 0-5 kg (OR 5.6), vs. ≥50 kg]. The final model developed using the derivation cohort after internal cross-validation (N=2029; C-statistic 0.83, Hosmer-Lemeshow Goodness of Fit P=0.81) performed well in the independent validation cohort (N=1194, C-statistic 0.81, HL P=0.68), suggesting excellent prediction in a contemporary cohort of pediatric HF patients as shown in the calibration plot in Figure 1. Conclusion This heart failure risk-prediction model using 5 baseline clinical factors at the time of listing has excellent prediction characteristics for 30-day mortality in a contemporary cohort of children. The model may be useful to support decision-making surrounding referral for advanced cardiac therapies including HT and VAD support. [ABSTRACT FROM AUTHOR]

Recurrent myopericarditis, characterized by repeated episodes of pericardial and myocardial inflammation, can be a diagnostic conundrum. We present one such case ultimately found to have a desmoplakin (DSP) gene mutation. Our patient was a previously well adolescent male with a several year history of episodic chest pain and significant troponin elevation. He had mild left ventricular (LV) systolic dysfunction by echocardiography, with no ventricular dilation, pericardial effusion or valvar dysfunction. He had intermittent ventricular bigeminy. Coronary arteries were normal. Cardiac MRI revealed late gadolinium enhancement involving the anterior and lateral LV walls and interventricular septum. Myocardial biopsy revealed patchy interstitial fibrosis. Genetic testing revealed a likely pathogenic DSP mutation, c.123C>G (p.Tyr41*), predicted to cause loss of normal protein function. The variant is uncommon in the general population and several downstream nonsense variants have been associated with cardiomyopathy, supporting pathogenicity. DSP is an essential protein in desmosomes, intercellular complexes responsible for maintaining cell-cell adhesion. Desmosomal mutations can cause arrhythmogenic cardiomyopathy, in which cardiac myocytes undergo fibroadiposis resulting in ventricular dysfunction, arrhythmias and sudden death. New evidence supports that DSP mutations can cause an inflammatory phenotype distinct from typical arrhythmogenic cardiomyopathy, characterized by predominant LV involvement, recurrent episodes of myocardial injury and fibrosis preceding systolic dysfunction. Our patient fits the novel description of DSP cardiomyopathy. His management plan includes reverse remodeling agents, surveillance for arrhythmia and cardiac dysfunction, restriction from competitive sports, and cascade genetic screening. Our case highlights the role of cardiomyopathy/arrhythmia genetic panels in patients with recurrent, unexplained myocardial inflammation. [ABSTRACT FROM AUTHOR]

Previous studies suggest the use of waitlist exceptions may be lower in pediatric heart transplant (HT) candidates with low socioeconomic status. However, reports are limited to eras prior to 2016 when UNOS listing criteria revisions to standardize the exception process were implemented. We sought to determine whether there is evidence of racial or geographic disparities in utilization of waitlist exceptions during the current era. UNOS data were used to identify all US children <18 years of age at listing for isolated orthotopic HT from 2016-2022. Patients were categorized based on if initially listed by exception, creating 4 mutually exclusive categories (1A standard vs exception; 1B standard vs. exception). Center-specific variation in the use of listing exceptions was analyzed. Of 4,277 children listed since 2016, 60% were listed UNOS status 1A (53% standard vs. 7% exception), 22% status 1B (15% standard vs. 7% exception) while 19% were listed status 2. Common cardiac diagnoses among 1A and 1B exception candidates were CHD (34%), RCM (12%), HCM (9%), and HT graft failure (11%). While no racial group differential was evident in the use of 1A exceptions, Black candidates were 13% less likely than White candidates to be listed by 1B exception. Substantial center-based variation exists in the use of listing exceptions among 45 high-volume programs where 0 to 33% of patients were listed by exceptions (Figure) including 0 to 20% of patients by 1A exception. Patients listed by exception (1A and 1B) had lower waitlist mortality conferring a survival advantage. In the current era, there appears to be differential rates of listing pediatric HT candidates by 1B exception based on race, which may lead to racial disparities in outcome. Center-specific variation in the use of listing exceptions may also contribute to geographic disparities in outcome. Further research is needed to understand and address disparities in the use of exceptions by race and region. [ABSTRACT FROM AUTHOR]

Sudden cardiac arrest (SCA) is a prevailing cause of mortality after pediatric heart transplant (HT) but remains understudied. The purpose of this study was to analyze the incidence, outcomes and risk factors for SCA at our center. Retrospective review of all pediatric HT patients at our center from 1/1/2009-9/1/2021. SCA was defined as an abrupt loss of cardiac function requiring cardiopulmonary resuscitation and/or mechanical circulatory support (MCS). Events that occurred in the first post-operative week, while on MCS, or in the setting of limited resuscitative wishes were excluded. Patient characteristics and risk factors were analyzed. Of 254 transplants during the study period, 16 (6%) experienced SCA at a median of 2 (1, 4) years post-HT. Thirteen (81%) died from their initial event, 4 of those (31%) after placement on MCS. SCA accounted for 30% of the 46 deaths during this time period. Seven (44%) events occurred at home. In univariate analysis, black race, internal cardiac defibrillator, history of post-HT extracorporeal membrane oxygenation (ECMO), prior cellular rejection (ACR) episode, retransplantation, and diagnosis of allograft vasculopathy (CAV) were associated with SCA (P =0.02-0.001, Table 1). In multivariable analysis, history of post-HT ECMO retained significance. [OR 14.5, 95% CI: 3.4-62.5, P <0.001] SCA occurs relatively early after pediatric HT and is often fatal. Nearly half of events happen at home. Patients with a history of ACR, CAV, retransplant, and prior history of ECMO are at increased risk. Multicenter investigation is needed to better understand SCA, reduce occurrence and improve outcomes. [ABSTRACT FROM AUTHOR]

Studies suggest that pediatric heart transplant (HT) waitlist mortality has declined. The impact of factors like refinements to the heart allocation system, patient selection, greater ABO incompatible (ABO-I) HT and VAD support are unknown. We examined the 20-year trend in waitlist mortality to identify factors associated with declining mortality and whether allocational inefficiencies persist. All children <18 years listed for isolated HT from 1999-2020 were identified using OPTN data and grouped into 3 eras (Era 1: 1999-2006; Era 2: 2006-2016; Era 3: 2016-2020) based on when UNOS revised the heart allocation system. Cox proportional hazards modeling was used to identify factors associated with death or delisting due to deterioration. Overall 11,374 patients met inclusion criteria (3,248 in Era 1; 5,378 in Era 2; 2,748 in Era 3). Waitlist mortality declined significantly across eras (21%, 17%, 13%, P<0.001). The prevalence at listing of major risk factors for mortality declined across eras including a reduction by 47% in ECMO use (11% to 6%, P<0.001), 33% in ventilator use (27% to 18%, P<0.001), 26% in dialysis use (2.5% to 1.8%, P=0.08); in contrast VAD use at listing increased by 243% (6% to 15%, P<0.001). Infant mortality declined significantly (27% to 20%, P<0.001) with a 48% decline in mortality for blood group O patients (relative to the background decline for all blood groups) and a 69% decline in infant VAD mortality (P<0.01). In Era 3, RCM and re-transplant patients not eligible for status 1A without exception had higher mortality than 1A DCM patients on LVAD support (16% vs 5.3%, P<0.01). Pediatric HT waitlist mortality has declined significantly over the past 20 years. There is evidence to suggest that greater VAD use, revisions to organ allocation, refinements in patient selection and ABO-I transplant may all contribute. Organ allocation inefficiencies persist under the current allocation system suggesting opportunities for allocation improvement may still exist. [ABSTRACT FROM AUTHOR]

On October 18, 2018, UNOS made important revisions to the adult allocation system for heart transplant (HT). Although the revisions primarily affect the prioritization of adult HT candidates, it could impact pediatric candidates indirectly as adult candidates listed Status 1 or 2 take priority over pediatric Status 1B and 2 candidates. We sought to determine if there was any effect on donor offers, declines and waitlist outcomes for pediatric candidates in light of the adult allocation change. All children <18 listed for HT within a 2-year period before and after the adult allocation revision was implemented were identified using OPTN data. Match-run analysis was also performed to examine the offer and decline rates. The primary endpoints were candidate transplantation and mortality rates. A total of 2,397 children met the study inclusion criteria, including 1,295 children listed before and 1,102 children listed after the adult policy change. The two cohorts were similar with respect to age, weight, cardiac diagnosis, ECMO, ventilator, VAD use, and insurance status. Nationwide offers to pediatric 1A candidates increased 34% per day, though center rejection of offers also rose a similar amount (41%). Pediatric candidates listed Status 1B and 2 also received more offers with a similar rise in center rejections, though the increases were smaller than for 1A candidates. Transplantation and mortality within 30-, 60- and 90-days did not change for 1A/1B candidates perhaps owing to the concomitant rise in center rejections of offers. There was a modest but significant decline in the likelihood of 30- and 60-day transplantation for patients listed at Status 2 following the change, though the likelihood of 90-day transplantation was comparable. The 2018 changes to the adult allocation system have, if anything, resulted in an increased flow of donor offers to pediatric candidates, however transplantation rates for children listed 1A and 1B appear similar before and after the change, partly because the rise in offers was associated with a rise in offer rejections. For pediatric Status 2 candidates, transplantation was slightly lower at 30- and 60-days, but comparable at 90 days. More work is needed to reduce offer rejections to increase the transplantation rate for pediatric HT candidates. [ABSTRACT FROM AUTHOR]

Extracorporeal membrane oxygenation (ECMO) can be used to rescue patients with graft dysfunction after heart transplant (HT) and is associated with high early mortality. Less is known about long-term prognosis after post-HT ECMO. The purpose of this study was to analyze the incidence and outcomes for post-HT ECMO at a high-volume pediatric heart transplant center. Retrospective review of all patients who underwent HT at Lucile Packard Children's Hospital Stanford from 1/2009 - 9/2021. Patient characteristics and risk factors were analyzed. Early Graft Failure (EGF) was defined as ECMO cannulation within 24 hours of transplant. Late Early Graft Failure (LEGF) was defined as ECMO cannulation between 1-14 days. All other patients were classified as Late Graft Failure (LGF). Long-term graft survival was defined as survival > 12 months after first ECMO course. Of 254 transplants during the study period, 21 patients (8.3%) required ECMO following HT. Indication for ECMO was confirmed or suspected rejection in 9 (42%), primary graft dysfunction in 6 (29%), and sudden cardiac arrest in 2 (9.5%). Of the 21 patients, 13 (62%) survived their ECMO course but only 7 (33%) remain alive with a median follow-up of 3.5 years (range 0.5-11 years). In the 6 (29%) patients who survived ECMO but subsequently died, median time to death was 62 days (range 8-445 days). There were 8 patients with EGF, 3 patients with LEGF, and 10 with LGF. LGF occurred at a median of 2.7 years (range 0.7-7 years) post HT. Survival to hospital discharge was 62.5% with EGF, 0% for LEGF, and 50% for LGF. Of the 5 patients with LGF surviving to hospital discharge, 2 subsequently died, 1 was retransplanted and 2 remain alive. Long term graft survival for EGF was 50% versus 30% for LGF. Early and late post-transplant ECMO has a high in-hospital mortality rate. Patients who undergo ECMO for late graft failure have worse long-term outcomes than those who undergo ECMO for early graft failure. Rescue graft support for late early graft failure was universally unsuccessful. [ABSTRACT FROM AUTHOR]

Pediatric ventricular assist device (VAD) therapy is a rapidly changing field where devices and applications are rapidly evolving. We sought to describe some of the most recent trends in pediatric VAD use and contemporary outcomes since UNOS began collecting VAD data on all listed patients regardless of whether they survived. All children ≤21 years of age listed for isolated HT between Jan 2004 and 2019 and underwent VAD placement were identified using OPTN data. Descriptive statistics were used to characterize recent trends in VAD utilization. Waitlist survival in children with cardiomyopathy, CHD and single-ventricle heart disease were estimated using the Kaplan-Meier method. Overall, 2059 children met the study inclusion criteria of whom the median age was 11 (IQR 1, 17), median weight 38 (11,66) kg, 26% were black; 18.3 had congenital heart disease (CHD) including 5.1% with single-ventricle (SV) HD. Forty-nine percent were supported with a VAD at listing, 72% at transplant and 13% received a VAD but was not supported at listing or transplant. Overall, 64% received LVADs, 31% BIVADs, 2.5% RVADs 1.7% total artificial hearts (TAH). Implants of the Berlin Heart fell dipped sharply to 34 in 2015 after a peak of 63 but have rebounded since in the era of bivalirudin. As of 2018, the Heartware HVAD was the most commonly implanted VAD in children (N=61) followed by the Berlin Heart (N=48), CentriMag/PediMag (N=18) and Heartmate III (N=11). The fastest growing segment of VAD patients are single-ventricle patients (Figure). The total number of pediatric VADs continues to grow at a brisk pace. The most recent era has seen growth of the Heartmate III and resurgence of the Berlin Heart EXCOR, after a brief decline in 2015. Single-ventricle and Heartmate III patients represent the fastest growing segment of the VAD population. [ABSTRACT FROM AUTHOR]

The match run is the automated mechanism by which UNOS prioritizes donor hearts to waitlist candidates for heart transplant (HT) based on medical urgency. We sought to determine how well match runs perform in sequencing patients according to their medical urgency after implementation of the 2016 pediatric heart allocation revisions. OPTN data were used to identify all match runs between March 21, 2016 and June 9, 2020 for each pediatric donor heart offered through UNOS to US waitlist candidates. The rank-order of candidates on the match run was compared to the rank-order based on medical urgency alone defined as the probability of survival on the day of the match run using a risk prediction model developed and validated during the prior 6 years. Overall, 634 donors generated 2,524 unique match runs during the study period when a total of 2,608 candidates were listed for pediatric HT. The median age of donors was 5 years (Q1, Q3, 1, 13), median weight 21 (11, 54) kg with the most common cause of death natural causes (26%), non-motor vehicle accidents (MVA) (22%) and MVA (16%). The risk-prediction model for death or deterioration included 8 variables (age, weight, cardiac diagnosis and cardiac support). When the survival model was applied to the match run candidates within zone, 26% of candidates were ranked out of survival order (i.e. had a rank-reversal) (Table). Of these, 69% of rank-reversals involved candidates within the same UNOS status levels whereas 41% involved candidates spread across UNOS status levels. There is evidence to suggest that the 2016 revision to the pediatric donor heart allocation system fails to sequence waitlisted candidates according to medical urgency, which affects a substantial fraction of match runs. Misclassification of patient risk by UNOS status level and within UNOS status levels each contribute rank-reversals. Rank-ordering patients based on a continuous survival probability model could address both problems. [ABSTRACT FROM AUTHOR]

Data suggest that pediatric heart transplant (HT) centers can reduce waitlist time by expanding donor catchment vis expanded parameters including the maximal donor weight range. Contrary to donor weight ranges, little is known about the effect of increasing the donor distance (DD) range. We sought to determine whether increasing the DD range can reduce waitlist time and how well actual DD predicts ischemic time (IT). All US children <18 years listed for HT at centers with ≥20 HT since 2007 were identified using OPTN data. Center variation in maximal DD range, defined as the median value of a center's maximal DD range, was analyzed and compared to actual DD. Pearson correlation was used to examine the correlation between actual DD and IT. Cox proportional hazards analysis was used to determine whether maximal DD range is associated with waitlist time. Among 4,240 children who met study criteria, the median age was 2 (IQR 0, 11) years, weight 12 (6, 35) kg, 53% had CHD. Centers varied considerably in their maximal DD range (1000-10,000 miles); median 1500 miles (Figure A). Overall, 86% of donors originated from ≤500 miles; 97% ≤1,000 miles (Figures A & B) with sharp drop-offs at 500 and 1000 miles (Figure B). After adjusting for patient factors, maximal DD range was associated with a shorter waitlist time. The correlation between actual DD and IT is fair (R=0.69) but explains only half (R2=0.49) of the variability in IT. Pediatric HT centers vary considerably in their maximal donor distance ranges, though most donors still fall within 500-1000 miles of recipients. Increasing the maximal DD range appears is associated with a shorter waitlist time. Actual DD explains only half of the variability in IT. Further research is needed to understand the optimal regional sharing distance for organ allocation and whether contemporary navigational software could better predict IT than the linear distance to the donor hospital. [ABSTRACT FROM AUTHOR]

In June 2018, the US Food and Drug Administration approved Prograf granules for pediatric solid-organ heart transplant without a US trial. This was due to concerns over compounding errors associated with pharmacy preparation of Prograf suspension for children who cannot swallow capsules. We reviewed our early experience converting children from Prograf suspension to granules to ensure safe transition practices. All children transitioned from Prograf suspension to Prograf granules at a single center in 2019 were identified using pharmacy records. The starting dose for the transition from compounded liquid to granules was determined by using a one to one dosing conversion. The steady dose of Prograf pre and post conversion were compared, as was the time to reach a therapeutic level. Patients with modified target goals (e.g. secondary to infection) before or after conversion were excluded. Between January and September 2019, a total of 12 children were converted from Prograf suspension to Prograf granules of whom 9 met the inclusion criteria. Of these, the median age was 6.25 (IQR 4, 8) years, the median weight was 17 (15, 21) kg; 56% were female and 67% had prior congenital heart disease. Prior to conversion, the mean daily dose was 0.106 (SD 0.07) mg/kg. Following conversion, the mean daily dose was 0.112 (SD 0.08) mg/kg, a 15% increase on average. On average, 3 levels were obtained before a goal target level was achieved at a mean of 34 days after conversion. Children transitioned from Prograf suspension to granules often required a dosing change to achieve the same target level on Prograf granules. The number of dose increases outnumbered dose decreases. Increasing the frequency of monitoring tacrolimus levels after conversion may help to foreshorten the period of time outside the goal range. [ABSTRACT FROM AUTHOR]

As the use of pediatric ventricular assist devices (VAD) has increased, more children are being supported with VADs for single-ventricle heart disease (SVD). Little is known about outcomes for this rapidly growing population of advanced HF patients. We sought to examine trends in VAD use for SVD and to assess outcomes. Organ Procurement and Transplant Network (OPTN) data were used to identify all children ≤21 years who underwent VAD placement between 2004 and 2020 for SVD. Cox proportional hazard modeling was used to identify risk factors for mortality defined as death or clinical deterioration. Of 1955 children with SVD, 315 were supported with an MCS device (145 SVADs and 170 ECMO only). Of the SVADs, 142 (97%) received an SVAD alone as the primary device, 2 (1%) received BIVADs and 1 (1%) a TAH. The most common VAD brands were the Berlin Heart EXCOR (N=44, 30%), the CentriMag/PediMag (N=40, 28%), Heartware HVAD (N=35, 24%), and the CentriMag/PediMag (ZZ%) and the Heartmate III (N=8, 6%). Since 2011 (when complete VAD survival data become available), overall survival to HT was 62% of whom 58% reached transplant; 38% died or deteriorated, and 2% recovered. Survival was significantly worse compared to pediatric VAD patients supported for DCM and comparable to patients supported for 2-ventricle CHD (P=0.79) (Find). Survival to transplant was highest for adult continuous flow devices (77%) and lower for the CentriMag/PediMag system (63%) and the Berlin Heart EXCOR (63%). VAD outcomes for bridge to transplant for single-ventricle heart disease patients are similar to other forms of 2-ventricle CHD but inferior to DCM. The highest survival appears to be in patients receiving adult CF devices with room for improvement in smaller patients receiving non-dischargeable devices. [ABSTRACT FROM AUTHOR]

In June 2018, the US Food and Drug Administration approved Prograf granules for pediatric solid-organ heart transplant without a US trial. This was due to concerns over compounding errors associated with pharmacy preparation of Prograf suspension for children who cannot swallow capsules. We reviewed our early experience converting children from Prograf suspension to granules to ensure safe transition practices. All children transitioned from Prograf suspension to Prograf granules at a single center in 2019 were identified using pharmacy records. The starting dose for the transition from compounded liquid to granules was determined by using a one to one dosing conversion. The steady dose of Prograf pre and post conversion were compared, as was the time to reach a therapeutic level. Patients with modified target goals (e.g. secondary to infection) before or after conversion were excluded. Between January and September 2019, a total of 12 children were converted from Prograf suspension to Prograf granules of whom 9 met the inclusion criteria. Of these, the median age was 6.25 (IQR 4, 8) years, the median weight was 17 (15, 21) kg; 56% were female and 67% had prior congenital heart disease. Prior to conversion, the mean daily dose was 0.106 (SD 0.07) mg/kg. Following conversion, the mean daily dose was 0.112 (SD 0.08) mg/kg, a 15% increase on average. On average, 3 levels were obtained before a goal target level was achieved at a mean of 34 days after conversion. Children transitioned from Prograf suspension to granules often required a dosing change to achieve the same target level on Prograf granules. The number of dose increases outnumbered dose decreases. Increasing the frequency of monitoring tacrolimus levels after conversion may help to foreshorten the period of time outside the goal range. [ABSTRACT FROM AUTHOR]

Data suggest that pediatric heart transplant (HT) centers can reduce waitlist time by expanding donor catchment via expanded parameters including the maximal donor weight range. Contrary to donor weight ranges, little is known about the effect of increasing the donor distance (DD) range. We sought to determine whether increasing the DD range can reduce waitlist time and how well actual DD predicts ischemic time (IT). All US children <18 years listed for HT at centers with ≥20 HT since 2007 were identified using OPTN data. Center variation in maximal DD range, defined as the median value of a center's maximal DD range, was analyzed and compared to actual DD. Pearson correlation was used to examine the correlation between actual DD and IT. Cox proportional hazards analysis was used to determine whether maximal DD range is associated with waitlist time. Among 4,240 children who met study criteria, the median age was 2 (IQR 0, 11) years, weight 12 (6, 35) kg, 53% had CHD. Centers varied considerably in their maximal DD range (1000-10,000 miles); median 1500 miles (Figure A). Overall, 86% of donors originated from ≤500 miles; 97% ≤1,000 miles (Figures A & B) with sharp drop-offs at 500 and 1000 miles (Figure B). After adjusting for patient factors, maximal DD range was associated with a shorter waitlist time. The correlation between actual DD and IT is fair (R=0.69) but explains only half (R2=0.49) of the variability in IT. Pediatric HT centers vary considerably in their maximal donor distance ranges, though most donors still fall within 500-1000 miles of recipients. Increasing the maximal DD range is associated with a shorter waitlist time. Actual DD explains only half of the variability in IT. Further research is needed to understand the optimal regional sharing distance for organ allocation and whether contemporary navigational software could better predict IT than the linear distance to the donor hospital. [ABSTRACT FROM AUTHOR]

Purpose Primary graft dysfunction following heart transplantation (HT) is associated with significant morbidity and mortality. The aim of this study was to assess the incidence, risk factors, and outcomes of pediatric patients requiring extracorporeal membrane oxygenation (ECMO) support post-HT. Methods This study utilized an existing data linkage between the PHIS and SRTR databases from which pediatric HT recipients were identified (2002-2016). Post-HT ECMO support was identified by billing codes within one day of HT. Logistic regression was performed to assess risk factors for ECMO post-HT. Kaplan-Meier analyses assessed in-hospital mortality and post-discharge survival. Results A total of 2,820 patients were included with 224 (7.9%) requiring ECMO post-HT. Risk factors independently associated with the need for ECMO included age <1 year (AOR 2.2, p=0.002) or 1-5 years (AOR 2.1, p=0.003), congenital heart disease (AOR 1.5, p=0.04), re-transplant (AOR 2.3, p=0.03), ECMO support at HT (AOR 22.8, p<0.001), and VAD support at HT (AOR 2.2, p<0.001). A total of 32 (14.3%) patients died on ECMO, 1 (0.5%) was re-transplanted off ECMO, and 191 (85.3%) were decannulated (Figure). Survival to discharge dropped dramatically based on the duration of ECMO support. Survival was 89% for those with 1-3 days of support, 79.1% for 4-6 days, 63.2% for 7-9 days, and 18.8% for ≥10 days. While in-hospital mortality was greater for patients requiring ECMO (25% vs. 4%, p<0.001), there was no difference in long-term survival (median follow-up 4 years) for those who survived to hospital discharge (p=0.434). Conclusion There are identifiable risk factors associated with the need for ECMO in the post-HT period. Length of time on ECMO post-HT is strongly associated with the risk of in-hospital mortality. While patients who require ECMO post-HT demonstrate worse overall survival, those who survive to discharge have comparable outcomes to patients who did not require ECMO. [ABSTRACT FROM AUTHOR]