mTor-inhibition within the first days after pediatric heart transplantation is a potentially safe option to prevent cardiac allograft vasculopathy.

BACKGROUND: Immunosuppression after heart transplantation (HTX) with mammalian target of rapamycin (mTOR) inhibitors serves as a prophylaxis against rejection and to treat coronary vascular injury. However, there is little data on the early, preventive use of everolimus after pediatric HTX. METHODS: Retrospective study of 61 pediatric HTX patients (48 cardiomyopathy and 13 congenital heart disease), 28 females, median age 10.1 (range 0.1-17.9) years transplanted between 2008 and 2020. We analyzed survival, rejection, renal function, occurrence of lymphoproliferative disorder, and allograft vasculopathy together with adverse effects of early everolimus therapy combined with low-dose calcineurin inhibitors. RESULTS: Everolimus therapy was started at a median 3.9 (1-14) days after HTX. Median follow-up was 4.3 (range 0.5-11.8) years, cumulative 184 patient years. The estimated 1- and 5-year survival probability was 89% (CI 82%:98%) and 87% (CI 78%:97%). Four patients developed rejection (6.6%) (maximum 2R ISHLT criteria). No patient suffered from chronic renal failure. Three patients (4.9%) developed post-transplant lymphoproliferative disorder. Five patients suffered relevant wound-healing disorders after transplantation, four of them carrying relevant risk factors before HTX (mechanical circulatory support (n = 3), delayed chest closure after HTX (n = 3)). No recipient developed cardiac allograft vasculopathy. CONCLUSION: Initiating everolimus within the first 14 days after HTX seems to be well tolerated, enabling a low incidence of rejection, post-transplant lymphoproliferative disorders, renal failure, and reveals no evidence of cardiac allograft vasculopathy as well as good overall survival in pediatric heart transplant recipients.

Neurological Impact of Slower Rewarming during Bypass Surgery in Infants.

BACKGROUND: Hypothermia is a neuroprotective strategy during cardiopulmonary bypass. Rewarming entailing a rapid rise in cerebral metabolism might lead to secondary neurological sequelae. In this pilot study, we aimed to validate the hypothesis that a slower rewarming rate would lower the risk of cerebral hypoxia and seizures in infants. METHODS: This is a prospective, clinical, single-center study. Infants undergoing cardiac surgery in hypothermia were rewarmed either according to the standard (+1°C in < 5 minutes) or a slow (+1°C in > 5-8 minutes) rewarming strategy. We monitored electrocortical activity via amplitude-integrated electroencephalography (aEEG) and cerebral oxygenation by near-infrared spectroscopy during and after surgery. RESULTS: Fifteen children in the standard rewarming group (age: 13 days [5-251]) were cooled down to 26.6°C (17.2-29.8) and compared with 17 children in the slow-rewarming group (age: 9 days [4-365]) with a minimal temperature of 25.7°C (20.1-31.4). All neonates in both groups (n = 19) exhibited suppressed patterns compared with 28% of the infants > 28 days (p < 0.05). During rewarming, only 26% of the children in the slow-rewarming group revealed suppressed aEEG traces (vs. 41%; p = 0.28). Cerebral oxygenation increased by a median of 3.5% in the slow-rewarming group versus 1.5% in the standard group (p = 0.9). Our slow-rewarming group revealed no aEEG evidence of any postoperative seizures (0 vs. 20%). CONCLUSION: These results might indicate that a slower rewarming rate after hypothermia causes less suppression of electrocortical activity and higher cerebral oxygenation during rewarming, which may imply a reduced risk of postoperative seizures.

Risk Assessment of Red Cell Transfusion in Congenital Heart Disease.

BACKGROUND: The storage time of packed red blood cells (pRBC) is an indicator of change in the product's pH, potassium, and lactate levels. Blood-gas analysis is a readily available bedside tool on every intensive care ward to measure these factors prior to application, thus facilitating a calculated decision on a transfusion's quantity and duration.Our first goal is to assess the impact of storage time on pH, potassium, and lactate levels in pRBC. The influence of those parameters in the transfused children will then be evaluated. METHODS: In this retrospective study, we conducted blood-gas analyses of pRBC units before they were administered over 4 hours to neonates, infants, and children in our pediatric cardiac intensive care ward. All patients underwent regular blood-gas analyses themselves, before and after transfusion. RESULTS: We observed a highly significant correlation between the storage time of pRBC units and a drop in pH, as well as an increase in potassium and lactate of stored red cells (p< 0.0001). Median age of recipients with a complete blood-gas dataset was 0.1 (interquartile range [IQR] = 0.0-0.7) years; median pRBC storage duration was 6 (IQR = 5-8) days. Further analyses showed no statistically significant effect on children's blood gases within 4 hours after transfusion, even after stratifying for pRBC storage time ≤7 days and >7 days. CONCLUSION: Stored red blood cells show a rapid decrease in pH and increase in potassium and lactate. Slow transfusion of these units had no adverse effects on the recipients' pH, potassium, and lactate levels.

Quantitative collagen assessment in right ventricular myectomies from patients with tetralogy of Fallot.

AIMS: Patients with tetralogy of Fallot (TOF) are often affected by right ventricular fibrosis, which has been associated with arrhythmias. This study aimed to assess fibrosis distribution in right ventricular outflow tract (RVOT) myocardium of TOF patients to evaluate the utility of single histology-section analyses, and to explore the possibility of fibrosis quantification in unlabelled tissue by second harmonic generation imaging (SHGI) as an alternative to conventional histology-based assays. METHODS AND RESULTS: We quantified fibrosis in 11 TOF RVOT samples, using a tailor-made automated image analysis method on Picrosirius red-stained sections. In a subset of samples, histology- and SHGI-based fibrosis quantification approaches were compared. Fibrosis distribution was highly heterogeneous, with significant and comparable variability between and within samples. We found that, on average, 67.8 mm2 of 10 µm thick, histologically processed tissue per patient had to be analysed for accurate fibrosis quantification. SHGI provided data faster and on live tissue, additionally enabling quantification of collagen anisotropy. CONCLUSION: Given the high intra-individual heterogeneity, fibrosis quantification should not be conducted on single sections of TOF RVOT myectomies. We provide an analysis algorithm for fibrosis quantification in histological images, which enables the required extended volume analyses in these patients.

Implementing and Assessing a Standardized Protocol for Weaning Children Successfully From Extracorporeal Life Support.

Extracorporeal life support (ECLS) weaning is a complex interdisciplinary process with no clear guidelines. To assess ventricular and pulmonary function as well as hemodynamics including end-organ recovery during ECLS weaning, we developed a standardized weaning protocol. We reviewed our experience 2 years later to assess its feasibility and efficacy. In 2015 we established an inter-professional, standardized, stepwise protocol for weaning from ECLS. If the patient did not require further surgery, weaning was conducted bedside in the intensive care unit (ICU). Most of the weaning procedures are guided via echocardiography. Data acquisition began at baseline level, followed by four-step course (each step lasting 10 min), entailing flow-reduction and ending 30 min after decannulation. Moreover, data from the preprotocol era are presented. Between May 2015 and 2017, 26 consecutive patients (18 male), median age 177 days (2 days-20 years) required ECLS with median support of 4 (2-11) days. Excluding eight not weanable patients, 21 standardized weaning procedures were protocolled in the remaining 18 children. Our generally successful protocol-guided weaning rate (with at least 24-h survival) was 89%, with a discharge home rate of 58%. Practical application of the novel standard protocol seems to facilitate ECLS weaning and to improve its success rate. The protocol can be administered as part of standard bedside ICU assessment.

Long-Term Follow-Up on Health-Related Quality of Life After Mechanical Circulatory Support in Children.

OBJECTIVE: The objective of this study was to evaluate health-related quality of life in long-term survivors of mechanical circulatory support after acute cardiopulmonary failure. DESIGN: Prospective follow-up study. SETTING: Single-institutional in a center for congenital heart disease and pediatric cardiology. PATIENTS: Fifty patients who underwent 58 mechanical circulatory support therapies in our institution from 2001 to 2012. Median age was 2 (0-213) months, and median supporting time was 5 (1-234) days. Indication groups: 1) extracorporeal life support in low cardiac output: 30 cases (52%); 2) extracorporeal cardiopulmonary resuscitation: 13 cases (22%); 3) extracorporeal membrane oxygenation in acute respiratory distress syndrome: four cases (7%); and 4) ventricular assist devices: 11 cases (19%). INTERVENTIONS: Health-related quality of life was measured using standardized questionnaires according to the age group and completed by either parent proxies in children under 7 years old or the survivors themselves. MEASUREMENTS AND MAIN RESULTS: Fifty percentage of the patients were discharged home, and 22 long-term survivors (44%) were studied prospectively for health-related quality of life. Median follow-up period was 4.5 (0.3-11.3) years. Median age at follow-up was 5 (0.6-29) years old. Nineteen long-term survivors filled in the health-related quality of life questionnaires and were classified into three age groups: 0-4 years (n = 7): median health-related quality of life score, 69 (59-86) points; 4-12 years (n = 7): median health-related quality of life score, 50 (48-85) points; older than 12 years (n = 5): median health-related quality of life score, 90 (80-100) points. CONCLUSION: Long-term survivors' health-related quality of life as reported by their parents is lower than that of healthy children. However, the self-assessed health-related quality of life of the patients older than 12 years in our group is comparable to a healthy control population.

An Early Glenn Operation May be Associated with the Later Occurrence of Protein-Losing Enteropathy in Fontan Patients : Association of Early Glenn and Failing Fontan.

Protein-losing enteropathy (PLE) and plastic bronchitis (PB) are major causes of long-term mortality after Fontan operation. The objective of this study was to determine early clinical risk factors before the onset of PLE and PB. In a cohort study, 106 Fontan patients between 2005 and 2013 were examined. A median of 5.3 (1.5-8.5) years later, follow-up questionnaires were used to group the patients in a PLE or PB group (n = 14) and a non-PLE/PB group (n = 92). Prevalence of PLE was 9.4% (n = 10) and of PB 3.8% (n = 4). At follow-up, five patients (4.7%) died of PLE or PB. Median age at death was 6.2 years (IQR 10.5, 95% CI 5.3-23.4). We observed no significant group differences in gender distribution (p = 0.73), ventricular morphology (p = 0.87), surgical technique (p = 0.64), conduit fenestration (p = 0.34), age at Fontan operation (p = 0.54), and need for diuretics (p = 0.56). Hypoplastic left heart syndrome was more frequent in the PLE/PB group 50 vs. 22.8% (p = 0.03) OR 3.4 (95% CI 1.1-10.8). The modified Glenn procedure was performed at a median age of 4 months (IQR 4.0) in the PLE/PB group versus 8 months (IQR 8.0) in the non-PLE/PB group (p = 0.01). The early Glenn procedure and hypoplastic left heart syndrome may be associated with the development of PLE and PB.

Percutaneous Pulmonary Valve Implantation in the Patched Right Ventricular Outflow Tract 51 Years after Surgical Repair for Tetralogy of Fallot.

Percutaneous pulmonary valve implantation (PPVI) has become a widely practiced treatment option for patients with right ventricular outflow tract (RVOT) dysfunction. For this procedure, the Melody transcatheter pulmonary valve has become the most widely used system. On-label indications are limited to the treatment of failing circumferential conduits. However, there is growing but still limited experience with the off-label treatment of native or patched RVOTs. Here, the case is reported of a 57-year-old patient in whom redo-surgery for a dysfunctional pulmonary valve could be avoided by PPVI into the patched RVOT at 51 years after tetralogy of Fallot repair.

Progression of Aortic Regurgitation After Different Repair Techniques for Congenital Aortic Valve Stenosis.

We sought to characterize the incidence of AR progression and determine risk factors for AR progression in a consecutive series of infants and children after surgical correction of congenital aortic valvular and supravalvular stenosis. N = 30 patients underwent repair of the aortic valve for isolated congenital aortic valve stenosis (n = 14, 47 %) or combined with aortic regurgitation (AR, n = 16, 53%). N = 27 (90%) had a valvular and n = 3 patients (10%) presented with supravalvular pathology of their aortic valve. In n = 16 patients (53%) a bicuspid and in n = 2 (6%) patients, a unicuspid valve was present. Comparative survival was analyzed using the Cox model and log-rank calculations. Log-rank calculations were performed for variables reaching statistical significance in order to identify differences in survival between groups. Commissurotomy was performed in n = 20 patients, patch implantation in n = 4, cusp shaving in n = 8, cusp prolapse correction in n = 3, and cusp augmentation in n = 4 patients. In patients with combined dysfunction and preoperative AR, AR was successfully reduced by the initial procedure, and postoperatively the overall median AR grade was 1+ (range 0-2.5+, p = 0.001, for AR reduction among patients with any grade of preoperative AR). By the time of follow-up echocardiography, the median AR grade had significantly progressed toward 1.5+ (p = 0.004). At the time of mid-term follow-up at 3.2 years, none of the patients had moderate or severe AR grades >2.5+. Patients with a monocuspid aortic valve and patients who had some kind of patch implantation into their cusps or commissures or shaving of thickened cusps were more likely to present with progression of aortic regurgitation. Monocuspid aortic valve and patch implantation, as well as cusp shaving, are probably linked to AR progression. The standard procedure of commissurotomy results in an absolute rate of AR progression of 40 % over a medium-term follow-up period.

Disease severity, arrhythmogenesis, and fibrosis are related to longer action potentials in tetralogy of Fallot.

BACKGROUND: Arrhythmias may originate from surgically unaffected right ventricular (RV) regions in patients with tetralogy of Fallot (TOF). We aimed to investigate action potential (AP) remodelling and arrhythmia susceptibility in RV myocardium of patients with repaired and with unrepaired TOF, identify possible correlations with clinical phenotype and myocardial fibrosis, and compare findings with data from patients with atrial septal defect (ASD), a less severe congenital heart disease. METHODS: Intracellular AP were recorded ex vivo in RV outflow tract samples from 22 TOF and three ASD patients. Arrhythmias were provoked by superfusion with solutions containing reduced potassium and barium chloride, or isoprenaline. Myocardial fibrosis was quantified histologically and associations between clinical phenotype, AP shape, tissue arrhythmia propensity, and fibrosis were examined. RESULTS: Electrophysiological abnormalities (arrhythmias, AP duration [APD] alternans, impaired APD shortening at increased stimulation frequencies) were generally present in TOF tissue, even from infants, but rare or absent in ASD samples. More severely diseased and acyanotic patients, pronounced tissue susceptibility to arrhythmogenesis, and greater fibrosis extent were associated with longer APD. In contrast, APD was shorter in tissue from patients with pre-operative cyanosis. Increased fibrosis and repaired-TOF status were linked to tissue arrhythmia inducibility. CONCLUSIONS: Functional and structural tissue remodelling may explain arrhythmic activity in TOF patients, even at a very young age. Surprisingly, clinical acyanosis appears to be associated with more severe arrhythmogenic remodelling. Further research into the clinical drivers of structural and electrical myocardial alterations, and the relation between them, is needed to identify predictive factors for patients at risk.

Single-cell transcriptomics reveal different maturation stages and sublineage commitment of human thymic invariant natural killer T cells.

Invariant natural killer T cells are a rare, heterogeneous T-cell subset with cytotoxic and immunomodulatory properties. During thymic development, murine invariant natural killer T cells go through different maturation stages differentiating into distinct sublineages, namely, invariant natural killer T1, 2, and 17 cells. Recent reports indicate that invariant natural killer T2 cells display immature properties and give rise to other subsets, whereas invariant natural killer T1 cells seem to be terminally differentiated. Whether human invariant natural killer T cells follow a similar differentiation model is still unknown. To define the maturation stages and assess the sublineage commitment of human invariant natural killer T cells during thymic development, in this study, we performed single-cell RNA sequencing analysis on human Vα24+Vß11+ invariant natural killer T cells isolated from thymocytes. We show that these invariant natural killer T cells displayed heterogeneity, and our unsupervised analysis identified 5 clusters representing different maturation stages, from an immature profile with high expression of genes important for invariant natural killer T cell development and proliferation to a mature, fully differentiated profile with high levels of cytotoxic effector molecules. Evaluation of expression of sublineage-defining gene sets revealed mainly cells with an invariant natural killer T2 signature in the most immature cluster, whereas the more differentiated ones displayed an invariant natural killer T1 signature. Combined analysis with a publicly available single-cell RNA sequencing data set of human invariant natural killer T cells from peripheral blood suggested that the 2 main subsets exist both in thymus and in the periphery, while a third more immature one was restricted to the thymus. Our data point to the existence of different maturation stages of human thymic invariant natural killer T cells and provide evidence for sublineage commitment of invariant natural killer T cells in the human thymus.

Giant Ruptured Azygos Vein Aneurysm in a 33-Year-Old Woman.

The rupture of an azygos vein aneurysm is a very rare but catastrophic complication. Careful differential diagnosis of acute dyspnea and thoracic pain in young patients is essential for effective and early management. We present the case of a young woman with a huge, spontaneously ruptured vena azygos saccular aneurysm, successfully repaired via median sternotomy under cardiopulmonary bypass.

The Yasui procedure with a modified right ventricle-to-pulmonary artery connection utilizing autologous left atrial appendage as a free graft.

A 9-month-old girl born with an interrupted aortic arch type B, an arteria lusoria (aberrant right subclavian artery) and a multilevel left ventricular outflow tract obstruction underwent a Yasui completion after an initial interim palliation. After the Damus-Kaye-Stansel procedure was carried out and the Sano shunt had been established as a source of pulmonary flow, the reported procedure comprised closure of the ventricular septal defect and the intraventricular baffling of left ventricular outflow through a malaligned ventricular septal defect, incision and partial resection of a conal septum and establishment of a right ventricle-to-pulmonary artery connection using an autologous left atrial appendage as a free graft. This technique consisted of dissecting and harvesting the left atrial appendage, which was then used as autologous material for an interposition plasty connecting the central pulmonary artery bifurcation segment with the upper rim of the infundibulotomy. Native, autologous tissue thus comprised the backwall of the newly created right ventricle-to-pulmonary artery continuity. Porcine pericardial patch plasty was then used to complete the remaining circumference of the right ventricle-to-pulmonary artery continuity.

Model-driven survival prediction after congenital heart surgery.

OBJECTIVES: The objective of the study was to improve postoperative risk assessment in congenital heart surgery by developing a machine-learning model based on readily available peri- and postoperative parameters. METHODS: Our bicentric retrospective data analysis from January 2014 to December 2019 of established risk parameters for dismal outcome was used to train and test a model to predict postoperative survival within the first 30 days. The Freiburg training data consisted of 780 procedures; the Heidelberg test data comprised 985 procedures. STAT mortality score, age, aortic cross-clamp time and postoperative lactate values over 24 h were considered. RESULTS: Our model showed an area under the curve (AUC) of 94.86%, specificity of 89.48% and sensitivity of 85.00%, resulting in 3 false negatives and 99 false positives.The STAT mortality score and the aortic cross-clamp time each showed a statistically highly significant impact on postoperative mortality. Interestingly, a child's age was barely statistically significant. Postoperative lactate values indicated an increased mortality risk if they were either constantly at a high level or low during the first 8 h postoperatively with an increase afterwards.When considering parameters available before, at the end of and 24 h after surgery, the predictive power of the complete model achieved the highest AUC. This, compared to the already high predictive power alone (AUC 88.9%) of the STAT mortality score, translates to an error reduction of 53.5%. CONCLUSIONS: Our model predicts postoperative survival after congenital heart surgery with great accuracy. Compared with preoperative risk assessments, our postoperative risk assessment reduces prediction error by half. Heightened awareness of high-risk patients should improve preventive measures and thus patient safety.

Benefit From a Humanitarian Pediatric Congenital Heart Surgery Program Over a 10-Year Period.

Background: The charity organization Kinderherzen retten e.V. (KHR) enables humanitarian congenital heart surgery for pediatric patients from low- and middle-income countries at the University Heart Center Freiburg, Germany. The aim of this study was to assess periprocedural and mid-term outcomes of these patients for evaluation of KHR sustainability. Methods: Part one of the study comprised retrospective medical chart analyses of the periprocedural course of all KHR-treated children from 2008 to 2017, and part two a prospective evaluation of their mid-term outcome, assessed by questionnaires concerning survival, medical history, mental and physical development, and socioeconomic situation. Results: Of the 100 consecutively presented children from 20 countries (median age 3.25 years), 3 patients were not invasively treatable, 89 underwent cardiovascular surgery, and 8 received a catheter intervention only. There were no periprocedural deaths. Median postoperative duration of mechanical ventilation, intensive care stay, and total hospital stay was 7 (interquartile range [IQR] 4-21) hours, 2 (IQR 1-3) days, and 12 (IQR 10-16) days, respectively. Mid-term postoperative follow-up demonstrated a 5-year survival probability of 94.4%. The majority of patients received continued medical care in their home country (86.2% of patients), were in good mental and physical condition (96.5% and 94.7% of patients, respectively), and able to engage in age-appropriate education/employment (98.3% of patients). Conclusions: Cardiac, neurodevelopmental, and socioeconomic outcomes of patients treated via KHR was satisfactory. Thorough pre-visit evaluation and close contact with local physicians are crucial when providing this high-quality, sustainable, and viable therapeutic option for these patients.

Transposition of great arteries with left outflow tract obstruction and non-committed VSD: surgical management and late results.

OBJECTIVES: Transposition of the great arteries with ventricular septal defect (VSD) and left ventricular outflow tract obstruction (LVOTO) is a rare malformation. Our objective was to report on management and results of the cohort with non-committed VSD from a national registry for congenital heart disease. METHODS: Multicentre data were screened in the German National Registry for Congenital Heart Defects (Berlin, Germany) for repairs of transposition of the great arteries-VSD-LVOTO. A subgroup of patients with a remote/non-committed VSD was identified. End points included survival, reoperation and a composite of reoperations for LVOTO-/VSD- or baffle-related problem. RESULTS: N = 47 patients were identified treated in 14 different national centres between 1984 and 2020. The mean age was 14 (standard deviation 9) months, ranging from 7 days to 9.5 years. Nine patients (19%) were treated as neonates, 21 (45%) as infants and 17 children (36%) beyond the age of 1 year. Survival was >90% (80-100%) at 20 years. Freedom from any reoperation was 30% (10-50%) at 20 years. Freedom from the composite end point was 72% (50-90%) at 20 years. Patients after Rastelli underwent more reoperations compared to those without intraventricular baffle (freedom from reoperation 14% vs 50%, P = 0.1). The rates of the composite end point were similar when comparing Rastelli to other techniques (63% vs 83%, P = 0.32). CONCLUSIONS: The Rastelli operation yields robust results in the setting of non-committed VSD. Late results after neonatal arterial switch operation are outstanding. If LVOTO is not resectable and neonatal arterial switch operation suboptimal, interim palliation does not negatively impact outcome, patients can be safely delayed to beyond 1 year of age.

Right ventricular outflow tract reconstruction with decellularized porcine xenografts in patients with congenital heart disease.

BACKGROUND AND AIM OF THE STUDY: Decellularized xenogeneic pulmonary valves have been introduced for right ventricular outflow tract (RVOT) reconstruction in congenital heart disease. In the present study, the intermediate-term results from three institutions were analyzed. METHODS: Between January 2006 and September 2008, a total of 61 patients (median age 7 years; range: 9 days to 50 years; median body weight 21 kg; range: 1.9-140 kg) underwent RVOT reconstruction with either the Matrix P (n = 9) or Matrix P Plus (n = 52) tissue-engineered conduit. Eighteen patients underwent surgery in infancy, and 31 patients had previously undergone one or more RVOT interventions or operations. RESULTS: The valve sizes ranged from 11 to 27mm. Five patients died during the hospital stay or within three months, from non-valve-related causes; hence, the early mortality was 8.2%. No deaths occurred during the follow up period. Reoperation due to valve failure became necessary in four patients; three patients underwent RVOT interventions due to distal anastomotic stenosis, and six reinterventions were performed distal to the valve due to hypoplastic branch pulmonary arteries. Patients with valve implantation during infancy showed a composite freedom from valve-related reoperation, catheter intervention or valve dysfunction (defined as dP(max) > 40 mmHg) of 87% at one and three years postoperatively. Both, computed tomography and magnetic resonance imaging studies demonstrated normal structural features, with no evidence of calcification. CONCLUSION: The Matrix P/Matrix Plus conduit represents a viable alternative for RVOT reconstruction in patients with congenital heart disease. The intermediate-term performance of the conduits was favorable compared to that of other currently available implants.

A Rare Case of Severe Dilated Cardiomyopathy in Early Infancy.

We report the case of a 3-month-old girl presenting with end-stage dilated cardiomyopathy and therapy-resistant cardiogenic shock. A left ventricular assist device (LVAD) Berlin Heart EXCOR was implanted, her organs recovered, and she was listed for heart transplantation. Two months later, while still on the LVAD, she was diagnosed with the rare genetic Alström syndrome. Weaning was no option, and she underwent successful heart transplantation at the age of 9 months. The follow-up 15 months later revealed an uneventful transplant course in a child with Alström syndrome.

Ex Vivo Allograft Perfusion for Complex Pediatric Heart Transplant Recipients.

BACKGROUND: Pediatric heart transplant (HTx) recipients with congenital heart defects require complex concomitant surgical procedures with the risk of prolonging the allograft's ischemic time. Ex vivo allograft perfusion with the Organ Care System (OCS; Transmedics, Andover, MA) may improve survival of these challenging patients. METHODS: In this retrospective, single-center study a consecutive series of 8 children with allografts preserved using the OCS was compared with 13 children after HTx with cold storage of the donor heart from March 2018 to March 2020. RESULTS: Median recipient age in the control group was 18 months (range, 1-189) versus 155 months (range, 83-214) in the OCS group, and the baseline differences between the 2 groups were not significant. Fifty percent of the children in the OCS group had complex congenital heart defects (vs 15% of the control subjects). Median operation time during HTx in the OCS group was 616 minutes (range, 270-809) versus 329 minutes (range, 283-617). Because of the time of ex vivo allograft perfusion (265 minutes [range, 202-372]) median total ischemia time was significantly shorter in the OCS group: 78 minutes (range, 52-111) versus 222 minutes (range, 74-326). The incidence of primary graft, renal, or hepatic failure did not differ between the groups. Graft function and the occurrence of any treated rejection at follow-up revealed no significant difference between the 2 groups. One-year survival was 88% in the OCS group (vs 85%). CONCLUSIONS: Ex vivo allograft perfusion enabled complex pediatric HTx, yielding outcomes as positive as those of children whose donor hearts were stored in ice-cold solution.