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 and 2021. The median age was 1044 days (interquartile range 108-3535), and the median weight was 13 kg (interquartile range 7-26). Overall survival at 10 years following heart transplantation was 71%, with most of the death being perioperative. On multivariable analysis, risk factors for survival included Black race (hazard ratio = 1.630, P = 0.0253), blood type other than B (hazard ratio = 2.564, P = 0.0052) and male donor gender (hazard ratio = 1.367, P = 0.0483). Recipient age, the use of ventricular assist device or extracorporeal membrane oxygenation were not significantly associated with survival. Twenty-four patients underwent retransplantation, and 10-year freedom from retransplantation was 98%. Rejection before hospital discharge and within 1 year from transplantation was 20% and 24%, respectively, with infants having lower rejection rates. CONCLUSIONS: Compared with 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. Most of the death is perioperative. Efforts to properly support these patients before transplantation might decrease early mortality and improve overall survival.

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 transplants in children with heterotaxy syndrome.

OBJECTIVES: End-stage congenital heart disease (CHD) in children with heterotaxy syndrome might necessitate a heart transplant (HTx). An HTx in heterotaxy patients can be associated with several technical (e.g. redo, systemic/pulmonary-venous/situs anomalies, pulmonary artery reconstruction) and extra-cardiac (e.g. ciliary dyskinesia, infections, gastrointestinal) challenges. Our goal was to determine if heterotaxy syndrome is associated with increased early or late transplant risks. METHODS: The United Network for Organ Sharing transplant database was merged with the Paediatric Health Information System administrative database to identify children with heterotaxy who received an HTx. Characteristics and outcomes were compared between children with heterotaxy and contemporaneous non-heterotaxy congenital and non-congenital cardiomyopathy control groups. RESULTS: After we merged the databases, we divided our cohort of 1122 patients into 3 groups: the heterotaxy (n = 143), group the non-heterotaxy congenital (n = 428) group and the cardiomyopathy (n = 551) group. There were differences in the characteristics between the 3 groups, with the heterotaxy group being comparable to the non-heterotaxy congenital group. The waiting list duration was longer for the heterotaxy than for the non-heterotaxy congenital and cardiomyopathy groups (91 vs 63 vs 56 days, P < 0.001). Early post-transplant complications were similar for all groups except for operative mortality, which was 1% for the cardiomyopathy and 4% for the heterotaxy and non-heterotaxy congenital groups (P < 0.001). The post-transplant hospital stay was shorter for the cardiomyopathy (57 days) compared to the non-heterotaxy congenital (99 days) and heterotaxy (89 days) groups (P < 0.001). Whereas rejection prior to discharge was comparable between the heterotaxy and the CHD groups, it was higher at 1 year for the heterotaxy (22%) than for the non-heterotaxy congenital (19%) and cardiomyopathy (13%) groups (P < 0.001). Survival at 5 years was superior for the cardiomyopathy (87%) compared to the heterotaxy (69%) and non-heterotaxy congenital groups (78%) (P < 0.001). For the heterotaxy group, no risk factors affecting survival were identified on multivariable analysis. CONCLUSIONS: Regardless of the complexity, an HTx in selected children with heterotaxy is associated with good mid-term outcomes. Despite early results that are comparable to those of other patients with CHD, the increasing rejection rate at 1 year and the relatively accelerated attrition at mid-term warrant further follow-up. Due to database limitations in defining morphologic and surgical details, further work is warranted to delineate anatomical and surgical variables that could affect 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.

A novel approach to retrograde autologous priming for infant, pediatric and adult populations undergoing congenital heart surgery.

INTRODUCTION: Retrograde Autologous Priming (RAP) of cardiopulmonary bypass (CPB) circuits is an effective way to reduce prime volume, commonly through the transfer of prime into separate reservoirs or circuit manipulation. We describe a simple and safe technique for RAP without the need for any circuit modifications or manipulations. METHODS: For this technique, a separate roller pump for ultrafiltration (UF) is used. After adequate heparinization and arterial cannulation, the UF pump is initiated slowly, removing prime through the effluent of the UF, replacing with the patient's blood from the aortic cannula. Once the arterial line and UF circuit are autologous primed, the arterial head displaces reservoir crystalloid toward the UF circuit at a flow rate equal to the UF pump, displacing the crystalloid prime with blood from the UF circuit, autologous priming the boot and oxygenator with blood, crystalloid again being removed by the effluent. After venous cannulation, the venous line prime is replaced with autologous blood, the crystalloid removed by the effluent of the UF circuit via the arterial head. During RAP, if the patient becomes hypovolemic, either autologous volume is transfused back to the patient, or CPB is initiated, without the need for circuitry modifications. RESULTS: The patient population in this sample consisted of 63 patients ranging between 6.1 kg and 115.6 kg. The smaller the patient, the less blood volume available for RAP and therefore the less prime volume able to be removed. Overall percent removal increases as our patients size increases compared to total circuit volume. CONCLUSION: This RAP technique is a safe and effective way to achieve a standardized asanguinous prime for many regardless of patient or circuit size in the absence of contraindications such as low starting hematocrit, emergency surgery or physiologic instability. Most importantly, this potentially reduces the amount of hemodilution patients see from CPB initiation and therefore the lowest nadir hematocrit and consequently the amount of required homologous blood products needed during surgery.

Normalizing Anti-Thrombin III for heparin management during routine cardiopulmonary bypass for congenital cardiothoracic surgery: A single institution practice review.

INTRODUCTION: Over the past decade, there has been an increase in the use of recombinant Anti-Thrombin III (AT-III) administration during neonatal and pediatric short- and long-term mechanical support for the replacement of acquired deficiencies. Recombinant AT-III (Thrombate) administration is an FDA licensed drug indicated primarily for patients with hereditary deficiency to treat and prevent thromboembolism and secondarily to prevent peri-operative and peri-partum thromboembolism. Herein we propose further use of Thrombate for primary AT-III deficiency of the newborn as well as for acquired dilution and consumption secondary to cardiopulmonary bypass (CPB). METHODOLOGY: All patients undergoing CPB obtain a preoperative AT-III level. Patients with identified deficiencies are normalized in the OR using recombinant AT-III as a patient load, in the CPB prime, or both. Patient baseline Heparin Dose Response (HDR) is assessed using the Heparin Management System (HMS) before being exposed to AT-III. If a patient load of AT-III is given, a second HDR is obtained and this AT-III Corrected HDR is used as the primary goal during CPB. Once CPB is initiated, an AT-III level is obtained with the first patient blood analysis. A subtherapeutic level results in an additional dose of AT-III. During the rewarm period, a final AT-III level is obtained and AT-III treated once again if subtherapeutic. A retrospective, matched analysis review of practice analyzing two groups, a Study Group (Repeat HDR, May 2022 onward) and Matched Group (Without Repeat HDR, July 2019 to April 2022), for age (D), weight (Kg) and operation was conducted. The focus of the study was to determine any change in heparin sensitivity identified post AT-III patient bolus load in the HDR (U/mL), Slope (U/mL/s), ACT (s), and total amount of heparin on CPB (U) and protamine (mg) used in each group. RESULTS: No significance was seen in Baseline AT-III (%), post heparin load HDR (U/mL), first CPB ACT (s), first CPB HDR (U/mL), or total CPB heparin (u/Kg) between the two groups. Statistical significance was seen in Baseline ACT (s), Baseline HDR (U/mL), Baseline Slope (U/mL/s), Post Heparin Load ACT (s), first CPB AT-III (%), and Protamine (mg/Kg) (p < .05). No statistical significance was seen in the Study Intragroup between pre versus post AT-III patient load baseline sample in ACT (s), however significance was seen in HDR (U/mL) and Slope (U/mL/s) (p < .05). CONCLUSION: Implementation of AT-III monitoring and therapy before and during CPB in conjunction with the HMS allows patients to maintain a steady state of anticoagulation with overall less need for excessive heparin replacement and potentially thrombin activation. The result is obtaining a steady state of anticoagulation, a reduced fluctuation in the heparin and ACT levels and a potential for lower co-morbidities associated with prolonged CPB times.

Prevalence of Branch Pulmonary Artery Reintervention Following the Arterial Switch Operation.

BACKGROUND: The arterial switch operation (ASO) is the preferred surgical procedure used to correct dextro-transposition of the great arteries. A known complication of the ASO is branch pulmonary arteries (PAs) stenosis, which may require reintervention. Our goal is to determine the frequency of reintervention after the ASO and any factors associated with reintervention. METHODS: This was a single center, retrospective study of infants who underwent the ASO from June 6, 2011 to February 21, 2021. The primary outcome was the prevalence of reintervention on the PAs following the ASO. RESULTS: Sixty-eight infants were analyzed; 9 (13%) patients had 10 reinterventions. The mean age at time of the ASO was 6.52 ± 6.63 days; weight was 3.34 ± 0.57 kg. Those with a reintervention had a longer bypass time (P = .047). Mean age at reintervention was 0.80 ± 0.72 years; mean time from the ASO to reintervention was 0.799 ± 0.717 years. Six surgical procedures, two stent placements, and four balloon angioplasties were performed on a total of 13 branch PAs. There was no increased risk for reintervention on the right versus left PA. After reintervention, there was an improvement in the minimal PA diameter and echo gradient. There were no adverse events or mortality related to the reintervention. Mean follow-up was 6.17 ± 2.94 years. CONCLUSION: The prevalence of branch PA reintervention following the ASO in our cohort was 13%. There is an association between longer cardiopulmonary bypass time and reintervention. After reintervention, there was an increase in PA diameter and a decrease in echo gradient.

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.

Myocardial bridge in a child with cardiac arrest and ventricular fibrillation: a bridge over troubled water?

Resuscitated cardiac arrest in a child triggers a comprehensive workup to identify an aetiology and direct management. The presence of a myocardial bridge does not automatically imply causation. Careful determination of the haemodynamic significance of the myocardial bridge is critical to avoid an unnecessary sternotomy and to provide appropriate treatment.

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.

Pediatric mechanical circulatory support - a review.

The history of mechanical circulatory support began in 1953, as the first heart-lung machine enabled surgeons to perform complex open heart surgery. Heart failure is more prevalent in adults than pediatric patients which has led to the development of devices for adults with end-stage heart failure at a faster pace. Pediatric mechanical circulatory support has been derived from adult durable devices and subsequently applied in the adolescent population. The application of adult devices in children is inherently problematic due to size mismatch, especially in smaller patients. There has been an increasing interest in developing durable pumps that are appropriate for children for several reasons, with the primary factor being the number of children with end-stage heart failure far exceeding the number of potential donors. Mechanical circulatory support (MCS) for children can be divided into short-term temporary support and long-term durable support. The goal of this review is to discuss the devices available for the pediatric population and review the options for support in complex patients including single-ventricle anatomy, biventricular support, and total artificial heart options. We will also briefly discuss the Pumps for Kids, Infants, and Neonates (PumpKIN) Trial and MCS registries, including the Advanced Cardiac Therapies Improving Outcomes Network (ACTION).

Left Main Coronary Artery Ostial Stenosis in a Pediatric Patient With Sudden Cardiac Arrest.

Pediatric resuscitated sudden cardiac arrest may result from diverse conditions and, therefore, warrants a comprehensive work-up. Although rare, coronary artery abnormalities must be ruled out in these patients. We describe a case with congenital left main coronary artery ostial stenosis diagnosed using advanced imaging techniques. (Level of Difficulty: Advanced.).

Norwood Operation With Partial Left Ventriculectomy for Neonatal Dilated Cardiomyopathy.

The combination of severe fetal mitral regurgitation diagnosed in utero, aortic stenosis, left ventricular dilatation, and dysfunction is associated with extremely poor prognosis. We report a neonate who underwent Norwood operation and left ventricular exclusion using partial left ventriculotomy and Alfieri mitral valve stitch. Left ventricular exclusion eliminated right ventricular compression and allowed survival and progression to subsequent second-stage palliation.

ABO-Incompatible Heart Transplant in Infants: A UNOS Database Review.

BACKGROUND: ABO-incompatible (ABOi) heart transplantation (HT) in infants has been used to reduce waiting list time and mortality with outcomes comparable to ABO compatible (ABOc). We sought to assess trends in ABOi listing and transplantation for infants within the United Network for Organ Sharing registry and to evaluate its influence on outcomes. METHODS: We reviewed infants listed for HT in the United Network for Organ Sharing registry (2007-2018). We compared demographic and clinical characteristics, waiting list duration, graft survival, and 1-year freedom from rejection between patients listed for ABOi and ABOc. Cochran-Armitage trend test, univariate nonparametric statistical methods, and Kaplan-Meier curves were used to analyze the data. RESULTS: During the study period, 2787 patients were listed for HT, 53% of whom were listed for ABOi. Median waiting list time for patients in blood group O receiving an ABOi transplant was significantly shorter (P < .0001). Among the 1862 patients who received HT, 15% were ABOi. The incidence of ABOi HT also increased over time. The pretransplant anti-A and anti-B titers in the ABOi group did not significantly affect outcomes. There was no difference in the incidence of rejection in the first year after transplant and no significant difference in posttransplant survival CONCLUSIONS: The number of infants listed and transplanted as ABOi has gradually increased over the past decade, with a significantly decreased waiting list time for ABOi transplants in blood group O. At 1 year after transplant, rejection was comparable between the ABOi and ABOc groups and there was no significant difference in survival.

Unusual Case of Common Arterial Trunk With Atresia of the Right Pulmonary Artery and Aortopulmonary Collaterals.

We describe a two-year-old African girl with late diagnosis of unusual case of common arterial trunk with two separate pulmonary artery branch origins from the ascending aorta, hypoplastic right pulmonary artery that becomes atretic and reconstitutes at hilum, and three aortopulmonary collaterals providing right lung blood supply. She underwent single-stage intracardiac repair and unifocalization of collaterals.