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Heart failure metrics specific to the pediatric population are required to successfully implement quality improvement initiatives in children with heart failure. Medication use at the time of discharge following admission for decompensated heart failure has been identified as a potential quality metric in this population. This study aimed to report medication use at discharge in the current era for children admitted with acute decompensated heart failure. All patients

Purpose The significance of atypical infiltrates, defined as eosinophils or plasma cells on endomyocardial biopsy (EMB) after pediatric heart transplant (HTx) is not known. We hypothesize that atypical infiltrates are associated with worse post-HTx outcomes. Methods We performed a retrospective cohort study of 96 consecutive patients status-post primary HTx (age Results Atypical infiltrates were seen in 24/96 (25%) patients. Of these patients, 14/24 (58%) had 1 EMB and 10/24 (42%) had >2 EMB with atypical infiltrates. Atypical cells were abundant in 6/24 (25%), while they were a rare cell type in 18/24 (75%). The presence of atypical infiltrates on EMB was associated with higher likelihood of reaching the composite outcome compared to no atypical infiltrates (HR 6.9 [2.9-16.3], Fig 1A). Two or more EMBs with atypical infiltrates were associated with greater risk of composite outcome compared to no atypical infiltrates (HR 11.1 [4.2-29.1], Fig 1B). All patients with abundant atypical infiltrates met the composite outcome within the study period (HR 21.6 [7.7-60.2], Fig 1C, compared to no atypical infiltrates). Conclusion Atypical infiltrates on EMB are associated with increased risk of CAV, graft failure, or death after HTx. The risk is higher with increasing frequency and greater extent of atypical infiltrates on EMB. Patients with atypical infiltrates are an at-risk population that require close follow up.

Purpose The number of patients with failing single ventricle physiology is increasing, and ventricular assist device (VAD) support in this population is challenging. The purpose of this study was to describe our clinical experience with VAD for failing Glenn physiology. Methods A retrospective review of clinical outcomes was conducted in patients that underwent durable VAD placement for failing Glenn circulation between 2010 and 2020 at Texas Children's Hospital. Results Ten patients met inclusion criteria; all had a morphologic right ventricle (RV): 6 hypoplastic left heart syndrome/variant and 4 with isomerism with RV dominant atrioventricular septal defect. INTERMACS profiles were 1 in 3 patients (1 with ECMO) and 2 in 7 patients. Four patients were intubated. Age, weight, and body surface area at VAD implantation were 3.2 (0.9-10.1) years, 13.0 (7.7-22.8) kg, and 0.50 (0.36-0.90) m2, respectively. The device-strategy included HVAD in 6, Jarvik 2015 in 1, and Berlin cannula (with Berlin and/or Rotaflow pumps) in 3. Concomitant Fontan completion was performed in 5 patients (1 with fenestration), while the other 5 remained with Glenn circulation. PaO2/FiO2 ratio (median, range) on postoperative day 1 was significantly higher with Fontan completion [192 (53-336)] than without [76 (59-78), p=0.05] except a patient with Glenn circulation on ECMO. The median duration of mechanical ventilation after VAD was 2 days (range, 1 - 14). There was 1 early mortality 8 days after HVAD placement with Fontan completion due to neurologic insult intraoperatively. The remaining 9 patients (90%) were bridged to transplant at a median support duration of 3.8 (0.1-16.6) months. Five of the 6 HVAD patients were able to be discharged home prior to transplant. One patient encountered a pump thrombus requiring pump exchange and 1 patient suffered a thromboembolic stroke due to a mobile intraventricular thrombus. One patient had a subdural and subarachnoid hemorrhage 27 days after VAD implantation, with complete neurologic recovery without deficits. Conclusion This single-institutional experience suggests long term VAD support is sustainable for failing Glenn physiology with accompanying Fontan completion in selected patients. Further studies are warranted to optimize long term VAD support in this challenging population.

Purpose There are limited data reporting outcomes of children with trisomy 21 undergoing heart transplantation (HTx). This project reports the waitlist and post-HTx outcomes of children with trisomy 21. Methods This is a retrospective cohort study of children with trisomy 21 listed for or who underwent HTx at 11 centers within North America and internationally. Demographic, medical, surgical, and post-HTx outcome data were collected and described. Results Twenty-one patients with trisomy 21 were listed for HTx from 1992 through 2019 (median age 8.5y, 43% male, 52% white). High-risk or failed repair of congenital heart disease was the indication for transplant in 16 (76%) patients with atrioventricular septal defect being the most common (N=12). Other diagnoses included dilated cardiomyopathy in 4 patients (secondary to anthracyclines in 2) and myocarditis in 1 patient. A total of 18 (86%) patients survived to transplant. Of this group, support at the time of transplant included inotropes (N=10, 56%), ventricular assist device (N=7, 39%), and mechanical ventilation (N=2, 11%). No patients required post-operative extracorporeal membrane oxygenation or dialysis. All centers reported the use of standard immunosuppression without alterations secondary to trisomy 21. All transplanted patients survived to hospital discharge with a median post-HTx length of stay of 19d. With a median follow-up of 2.9y, 16 (89%) patients were alive, 5 (28%) had rejection within the 1st year post-HTx, 2 (11%) developed post-transplant lymphoproliferative disorder (PTLD), and 7 (39%) were hospitalized for infection within the 1st year post-HTx. For the two post-HTx mortalities, the causes of death were 1) coronary allograft vasculopathy at 22y post-HTx and 2) multiple episodes of rejection and PTLD at 1.5y post-HTx (Figure). Conclusion Waitlist and intermediate post-HTx outcomes are acceptable in children with trisomy 21. The presence of trisomy 21 should not be an absolute contraindication to heart transplantation in the appropriate clinical setting.

Introduction Valvular disease in pediatric donor hearts may be a relative contraindication to graft use. Outcomes following use of donor hearts with milder forms of valvular disease have not been previously reported. We describe 4 cases of pediatric heart transplantation (HTx) in which the donor heart had a bicuspid aortic valve (BAV). Case Report Of the 469 HTx performed at our center since 1985, 4 donor hearts had a BAV. All recipients were female; median age 11 years (range 0.3 to 19 years). In all cases, the BAV was not discovered until after HTx. All donors were less than 30 years old. The patients were followed for a median of 6 years (range 2 to 9 years) with all patients alive at last follow up. Two patients transferred to adult care and 2 patients are followed by our clinic. In follow up, no patient required an aortic valve intervention or had infective endocarditis. At last review, no patient had greater than mild aortic insufficiency or more than mild aortic stenosis. Three patients developed mild to moderate left ventricular hypertrophy in the first year post-transplant that improved over time. One patient experienced a peri-operative embolic stroke at time of transplant unrelated to the bicuspid aortic valve. Summary On short- and intermediate-term follow up, donor hearts with bicuspid aortic valve demonstrated acceptable graft longevity and valvular function. A functionally normal bicuspid aortic valve in a pediatric heart transplant donor should not be a contraindication to organ acceptance.

Purpose Graft failure after heart transplant (HTx) due to allograft rejection or coronary artery vasculopathy (CAV) can result in cardiogenic shock requiring mechanical circulatory support (MCS). We present our institutional experience with the Impella®, a percutaneous ventricular assist device (VAD), in HTx patients in cardiogenic shock due to graft failure. Methods This is a single center, retrospective review of HTx patients who underwent Impella implantation from 10/2014 to 4/2020. Demographics, device implant techniques, complications, and clinical outcomes were analyzed. Results There were 19 Impella implants in 11 HTx patients with median age and weight of 16 years (range 6-25) and 61 kg (range 23-124). Graft failure was due to rejection in 55% (6/11), CAV in 18% (2/11), and non-specific graft failure in 27% (3/11). Median time from HTx to Impella implant was 42 months (range 9-175). Impella devices included CP (n=11), 5.0 (n=5), 2.5 (n=1), and RP (n=2). Median length of support per implant was 5 days (range 3-21). Devices were placed via femoral (15/19) or axillary (4/19) arterial access. Seven patients received Impella support once with a single implant each. One patient required 3 distinct admissions for shock due to rejection and received Impella support each time. Three patients required 9 device implants during their course primarily for recurrence of heart failure (HF) after trial off device. Two of these received simultaneous support with CP and RP devices for biventricular HF. ECMO with Impella was required in 4 patients; 2 had Impella after ECMO for left heart decompression and 2 were placed on ECMO after Impella to augment cardiac support. Device related complications per patient included: device malfunction in 2, major bleeding requiring transfusion in 2, hemolysis in 5, extremity arterial thrombus in 2, intracardiac thrombus in 1, and transient foot drop in 3. There was no limb ischemia, stroke, infection, or increase in aortic insufficiency in the study cohort. Survival to hospital discharge was 91% (10/11). Six patients were explanted for recovery, 2 were transitioned to durable VAD, and 2 were bridged to HTx. Conclusion Impella is a promising temporary MCS option with an acceptable risk profile for adolescent and young adult HTx patients in cardiogenic shock due to graft failure with means to facilitate recovery or bridge to durable VAD or re-transplant.

Purpose Therapeutic ranges of Mycophenolic Acid (MPA) concentrations have not been established in pediatric heart transplant recipients. There are limited data supporting are under the concentration-time curve (AUC) in adult heart transplant on outcomes such as rejection, but AUC monitoring may be not be feasible in clinical practice. The purpose of our study is to evaluate the relationship between mycophenolic acid (MPA) trough levels and incidence of biopsy proven rejection and adverse effects in pediatric heart transplant patients. Methods A single-center retrospective chart review was performed on patients receiving heart transplant between Jan 2011 and Dec 2015. Patients included for analysis were ≤18 years at transplant and received maintenance immunosuppression with tacrolimus, mycophenolate, and a corticosteroid. Endomyocardial biopsy grades up to one-year post transplant and simultaneous MPA levels were recorded. Patients with acute cellular rejection scores of 2R or 3R or immunopathologic evidence of antibody mediated rejection were considered as biopsy proven acute rejection (BPAR). Leukopenia, gastrointestinal side effects, and mycophenolate dose decreases were also recorded. Results A total of 47 patients were included in the final analysis. There were no significant differences in baseline demographics between patients who had BPAR and those who did not. Overall 24% of patients had at least 1 incidence of BPAR after heart transplant. The mean MPA trough levels between the group of patients with rejection (2.4 ug/mL +/- 1.62) and those without rejection (2.46 ug/mL +/- 1.74) was not significantly different (p=0.38). Mean MPA trough levels also were also not consistent when examining rejection by time from transplant. Only examining by individual MPA trough levels on biopsy days did we observe a significantly lower MPA trough 1.6 ug/mL +/- 1.05 in those with rejection versus those without 2.5 ug/mL +/- 1.69 (p=0.02). The mean MPA level associated with a dose decrease due to an adverse effect between these two groups was not significant. Conclusion MPA trough levels may have a relationship with incidence of biopsy proven rejection or with incidence of adverse events within one-year post transplant in this population. Controlled prospective studies with are warranted to further evaluate this potential relationship.

Introduction Recognition of ventricular assist device (VAD) complications such as aortic insufficiency (AI) are important to optimize long-term management. We highlight a case of the treatment of severe AI in a pediatric continuous flow (CF) VAD patient using transcatheter aortic valve replacement (TAVR). Case Report A 9-year-old male with congenitally corrected transposition of the great arteries and pulmonary atresia underwent staged surgical palliation including a Mustard and Rastelli operation. He developed severe left ventricular (LV) dysfunction with refractory heart failure and underwent implant of a HeartWare (Medtronic, Minneapolis MN) in the morphologic LV on the right side at almost 5 years of age (weight 13.7 kg, BSA 0.64 m2). His waitlist time was prolonged due to significant allosensitization. After 4 years on support, clinical signs of congestive heart failure (CHF) developed and BNP rose (1000 pg/mL) despite optimal VAD performance. Cardiac catheterization showed severe AI and pulmonary hypertension. Mean pulmonary arterial pressure was 40 mmHg with pulmonary vascular resistance of 8.5 WUm2 that was responsive to pulmonary vasodilators. The pulmonary hypertension was attributed to the AI. To avoid a difficult redo sternotomy, TAVR was deemed the optimal way to replace his aortic valve. He underwent catheterization and a 29 mm Edwards SAPIEN 3 valve (Edwards Lifesciences, Irvine CA) was placed in the aortic valve position via right carotid artery cut down using a 21 French sheath. The VAD speed was reduced to 1800 RPM and rapid ventricular pacing allowed for stabilization during valve deployment. Post TAVR, angiography showed resolution of AI with only mild perivalvar leak around the aortic valve. After discharge, he was noted to have a transient rise in lactate dehydrogenase from baseline and increased bruising due to unclear etiology. Within 5 months of his TAVR, his diuretics were weaned with marked improvement in his BNP and resolution of his CHF. Summary AI is a significant complication of long-term CF VAD support that can lead to detrimental hemodynamics and worsening CHF. TAVR may be a reasonable therapy to mitigate AI in high-risk children.