Waitlist Outcomes for Pediatric Heart Transplantation in the Current Era: An Analysis of the Pediatric Heart Transplant Society Database.

BACKGROUND: Waitlist mortality (WM) remains elevated in pediatric heart transplantation. Allocation policy is a potential tool to help improve WM. This study aims to identify patients at highest risk for WM to potentially inform future allocation policy changes. METHODS: The Pediatric Heart Transplant Society database was queried for patients <18 years of age indicated for heart transplantation between January 1, 2010 to December 31, 2021. Waitlist mortality was defined as death while awaiting transplant or removal from the waitlist due to clinical deterioration. Because WM is low after the first year, analysis was limited to the first 12 months on the heart transplant list. Kaplan-Meier analysis and log-rank testing was conducted to compare unadjusted survival between groups. Cox proportional hazard models were created to determine risk factors for WM. Subgroup analysis was performed for status 1A patients based on body surface area (BSA) at time of listing, cardiac diagnosis, and presence of mechanical circulatory support. RESULTS: In total 5974 children met study criteria of which 3928 were status 1A, 1012 were status 1B, 963 were listed status 2, and 65 were listed status 7. Because of the significant burden of WM experienced by 1A patients, further analysis was performed in only patients indicated as 1A. Within that group of patients, those with smaller size and lower eGFR had higher WM, whereas those patients without congenital heart disease or support from a ventricular assist device (VAD) at time of listing had decreased WM. In the smallest size cohort, cardiac diagnoses other than dilated cardiomyopathy were risk factors for WM. Previous cardiac surgery was a risk factor in the 0.3 to 0.7 m2 and >0.7 m2 BSA groups. VAD support was associated with lower WM other than in the single ventricle cohort, where VAD was associated with higher WM. Extracorporeal membrane oxygenation and mechanical ventilation were associated with increased risk of WM in all cohorts. CONCLUSIONS: There is significant variability in WM among status-1A patients. Potential refinements to current allocation system should factor in the increased WM risk we identified in patients supported by extracorporeal membrane oxygenation or mechanical ventilation, single ventricle congenital heart disease on VAD support and small children with congenital heart disease, restrictive cardiomyopathy, or hypertrophic cardiomyopathy.

Social Determinants of Health and Outcomes After Pediatric Ventricular Assist Device Implantation.

BACKGROUND: Limited research exists on the influence of social determinants of health (SDOH) on outcomes in pediatric patients with advanced heart failure receiving mechanical circulatory support. METHODS: Linkage of the Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) and Society of Thoracic Surgeon's Congenital Heart Surgery Database (STS-CHSD) identified pediatric patients who underwent ventricular assist device (VAD) implantation from 2012 to 2022 with available residential zip codes. Utilizing the available zip codes, each patient was assigned a Childhood Opportunity Index (COI) score. Level of childhood opportunity, race, and insurance type were used as proxies for SDOH. Major outcomes included death, transplant, alive with device, and recovery. Secondary outcomes were adverse events. Statistical analyses were performed using the Kaplan-Meier survival, competing risk analyses, and multivariable Cox proportional hazards model. RESULTS: Three hundred seventeen patients were included in the study. Childhood opportunity level and insurance status did not significantly impact morbidity or mortality after VAD implantation. White race was associated with reduced 1-year survival (71% in White vs. 87% in non-White patients, p = 0.05) and increased risk of pump thrombosis (p = 0.02). CONCLUSION: Childhood opportunity level and insurance status were not linked to morbidity and mortality in pediatric patients after VAD implantation. Notably, White race was associated with higher mortality rates. The study underscores the importance of considering SDOH in evaluating advanced therapies for pediatric heart failure and emphasizes the need for accurate socioeconomic data collection in future studies and national registries.

Efficient measurement of multiple ventricular assist device patient-reported outcomes: Creation of a 20-item profile from the MCS A-QOL study.

BACKGROUND: Patient-reported outcome (PRO) measures of distinct concepts are often put together into patient profile assessments. When brief, profile assessments can decrease respondent burden and increase measure completion rates. In this report, we describe the creation of 5 self-reported 4-item short forms and the Mechanical Circulatory Support: Measures of Adjustment and Quality of Life (MCS A-QOL) 20-item profile to assess PROs specific to adjustment and health-related quality of life (HRQOL) among patients who undergo left ventricular assist device (LVAD) implantation. METHODS: Using a cross-sectional sample of patients (n = 620) who underwent LVAD implantation at 12 U.S. sites or participated in the MyLVAD.com support group, we created 5 4-item short forms: Satisfaction with Treatment, ventricular assist device (VAD) Team Communication, Being Bothered by VAD Self-care and Limitations, Self-efficacy Regarding VAD self-care, and Stigma, which we combined into a 20-item profile. Analyses included intercorrelations among measures, Cronbach's alpha (i.e., internal consistency reliability)/score-level-specific reliability, and construct validity. RESULTS: The 620 patients were mean age = 57 years, 78% male, 70% White, and 56% on destination therapy LVADs. Intercorrelations among the 5 4-item measures were low to moderate (≤0.50), indicating they are associated yet largely distinct, and correlations with calibrated measures and 6-item short forms were ≥0.76, indicating their ability to reflect full-item bank scores. Internal consistency reliability for the 5 4-item short forms ranged from acceptable (≥0.70) to good (≥0.80). Construct validity was demonstrated for these measures. CONCLUSIONS: Our 5 4-item short forms are reliable and valid and may be used individually or together as a 20-item profile to assess adjustment and HRQOL in patients who undergo LVAD implantation.

Predicting Stroke for Pediatric Patients Supported With Ventricular Assist Devices: A Pedimacs Report.

BACKGROUND: The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs) provides detailed understanding on pediatric patients supported with ventricular assist devices (VADs). We sought to identify important variables affecting the incidence of stroke in pediatric VADs. METHODS: Between 2012 and 2022, 1463 devices in 1219 patients were reported to Pedimacs from 40 centers in patients aged <19 years at their first VAD implantation. Multiphase parametric hazard modeling was used to identify risk factors for stroke among all device types. RESULTS: Of the 1219 patients, the most common devices were implantable continuous (472 [39%]), followed by paracorporeal pulsatile (342 [28%]), and paracorporeal continuous (327 [27%]). Overall freedom from stroke at 6 months was higher in the recent era (2012-2016; 80.2% [95% CI, 77.1%-82.9%] vs 2017-2023; 87.9% [95% CI, 86.2%-89.4%], P = .009). Implantable continuous VADs had the highest freedom from stroke at 3 months (92.7%; 95% CI, 91.1%-93.9%) and 6 months (91.1%; 95% CI, 89.3%-92.6%), followed by paracorporeal pulsatile (87.0% [95% CI, 84.8%-88.9%] and 82.8% [95% CI, 79.8%-85.5%], respectively), and paracorporeal continuous (76.0% [95% CI, 71.8%-79.5%] and 69.5% [95% CI, 63.4%-74.8%], respectively) VADs. Parametric modeling identified risk factors for stoke early after implant and later. Overall, and particularly for paracorporeal pulsatile devices, early stroke risk has decreased in the most recent era (hazard ratio, 5.01). Among implantable continuous devices, cardiogenic shock was the major risk factor. For patients <10 kg, early hazard was only seen in the previous era. For congenital patients, early hazard was seen in nonimplantable device use and use of extracorporeal membrane oxygenation. CONCLUSIONS: The overall stroke rate has decreased from 20% to 15% at 6 months, with particular improvement among paracorporeal pulsatile devices. Risk factor analyses offer insights for identification of higher stroke risk subsets and further management refinements.

A comparison of quality-adjusted life years in older adults after heart transplantation versus long-term mechanical support: Findings from the SUSTAIN-IT study.

BACKGROUND: The quality-adjusted life year (QALY) measures disease burden and treatment, combining overall survival and health-related quality of life (HRQOL). We estimated QALYs in 3 groups of older patients (60-80 years) with heart failure (HF) who underwent heart transplantation (HT, with pre-transplant mechanical circulatory support [HT MCS] or HT without pre-transplant MCS [HT Non-MCS]) or long-term MCS (destination therapy). We also identified factors associated with gains in QALYs through 24 months follow-up. METHODS: Of 393 eligible patients enrolled (10/1/15-12/31/18) at 13 U.S. sites, 161 underwent HT (n = 68 HT MCS, n = 93 HT Non-MCS) and 144 underwent long-term MCS. Survival and HRQOL data were collected through 24 months. QALY health utilities were based on patient self-report of EQ-5D-3L dimensions. Mean-restricted QALYs were compared among groups using generalized linear models. RESULTS: For the entire cohort, mean age in years closest to surgery was 67 (standard deviation, SD: 4.7), 78% were male, and 83% were White. By 18 months post-surgery, sustained significant differences in adjusted average ± SD QALYs emerged across groups, with the HT Non-MCS group having the highest average QALYs (24-month window: HT Non-MCS = 22.58 ± 1.1, HT MCS = 19.53 ± 1.33, Long-term MCS = 19.49 ± 1.3, p = 0.003). At 24 months post-operatively, a lower gain in QALYs was associated with HT MCS, long-term MCS, a lower pre-operative LVEF, NYHA class III or IV before surgery, and an ischemic or other etiology of HF. CONCLUSIONS: Determination of QALYs may provide important information for policy makers and clinicians to consider regarding benefits of HT and long-term MCS as treatment options for older patients with HF.

Impact of prolonged ischemic time on pediatric heart transplantation outcomes: Improved outcomes in the most recent era.

BACKGROUND: Impacts of ischemic time (IT) on pediatric heart transplant outcomes are multifactorial. We aimed to analyze the effect of prolonged IT on graft loss after pediatric heart transplantation. We hypothesized that graft survival with prolonged IT has improved across eras. METHODS: Patients <18 years old in the Pediatric Heart Transplant Society database were included (N=6,765) and stratified by diagnosis and era (1993-2004, 2005-2009, and 2010-2019). Severe graft failure (SGF) was defined as death, retransplant, or need for mechanical circulatory support in the first 7 days post-transplant. Descriptive statistical methods were used to compare differences between patient characteristics and IT. Kaplan-Meier survival analysis compared freedom from graft loss, rejection, and infection. Multivariable analysis was performed for graft loss and SGF (hazard and logistic regression modeling, respectively). RESULTS: Diagnoses were cardiomyopathy (N = 3,246) and congenital heart disease (CHD; N = 3,305). CHD were younger, more likely to have an IT ≥4.5 hours, and more likely to require extracorporeal membrane oxygenation or mechanical ventilation at transplant (all p < 0.001). Median IT was 3.6 hours (interquartile range 2.98-4.31; range 0-10.5). IT was associated with early graft loss (HR 1.012, 95% CI 1.005-1.019), but not when analyzed only in the most recent era. IT was associated with SGF (OR 1.016 95%CI 1.003-1.030). CONCLUSIONS: Donor IT was independently associated with an increased risk of graft loss, albeit with a small effect relative to other risk factors. Graft survival with prolonged IT has improved in the most recent era but the risk of SGF persists.

Novel measures to assess ventricular assist device patient-reported outcomes: Findings from the MCS A-QOL study.

BACKGROUND: Generic and heart failure-specific measures do not capture unique aspects of living with a ventricular assist device (VAD). Using state-of-the-science psychometric measurement methods, we developed a measurement system to assess post-ventricular assist device adjustment and health-related quality of life (HRQOL). METHODS: Patients were recruited from 10/26/16-2/29/20 from 12 U.S. VAD programs. We created a dataset of participants (n = 620) enrolled before left (L)VAD implantation, with data at 3- or 6- months post-implantation (group1 [n = 154]), and participants enrolled after LVAD implantation, with data at one timepoint (group 2 [n = 466]). We constructed 5 item banks: 3 modified from existing measures and 2 new measures. Analyses included item response theory (IRT) modeling, differential item functioning tests for systematic measurement bias, and indicators of reliability and validity. RESULTS: Of 620 participants, 56% (n = 345) were implanted as destination therapy, 51% (n = 316) were <12 months post-implantation, mean age = 57.3 years, 78% (n = 485) male, 70% (n = 433) White, 58% (n = 353) married/partnered, and 58% (n = 357) with >high school education. We developed 5 new VAD item banks/measures: 6-item VAD Team Communication; 12-item Self-efficacy Regarding VAD Self-care; 11-item Being Bothered by VAD Self-care and Limitations; 7-item Satisfaction with Treatment; and 11-item Stigma. Cronbach's alpha reliability ranged from good (≥0.80) to excellent (≥0.90) for item banks/measures. All measures, except VAD Team Communication, demonstrated at least moderate correlations (≥0.30) with construct validity indicators. CONCLUSIONS: These measures meet IRT modeling assumptions and requirements; scores demonstrate reliability and validity. Use of these measures may assist VAD clinicians to inform patients about VADs as a treatment option and guide post-VAD interventions.

Assessing Donor-Recipient Size Mismatch in Pediatric Heart Transplantation: Lessons Learned From Over 7,500 Transplants.

BACKGROUND: To date, no studies have identified an optimal metric to match donor-recipient (D-R) pairs in pediatric heart transplantation (HT). OBJECTIVES: This study sought to identify size mismatch metrics that predicted graft survival post-HT. METHODS: D-R pairs undergoing HT in Pediatric Heart Transplant Society database from 1993 to 2021 were included. Effects of size mismatch by height, weight, body mass index, body surface area, predicted heart mass, and total cardiac volume (TCV) on 1- and 5-year graft survival and morbidity outcomes (rejection and cardiac allograft vasculopathy) were evaluated. Cox models with stepwise selection identified size metrics that independently predicted graft survival. RESULTS: Of 7,715 D-R pairs, 36.0% were well matched (D-R ratio: -20% to +20%) by weight, 39.0% by predicted heart mass, 50.0% by body surface area, 57.0% by body mass index, 71.0% by height, and 93.0% by TCV. Of all size metrics, only D-R mismatch by height and TCV predicted graft survival at 1 and 5 years. Effects of D-R size mismatch on graft survival were nonlinear. At both 1 and 5 years post-HT, D-R undersizing and oversizing by height led to increased graft loss, with graft loss observed more frequently with undersizing. Moderately undersized donors by height (D-R ratio: <-30%) frequently experienced rejection post-HT (P < 0.001). Assessing D-R size matching by TCV, minimal donor undersizing was protective, while oversizing up to 25% was not associated with increased graft loss. CONCLUSIONS: In pediatric HT, D-R appear most optimally matched using TCV. Only D-R size mismatch by TCV and height independently predicts graft survival. Standardizing size matching across centers may reduce donor discard.

Changing Strategy Between Bridge to Transplant and Destination LVAD Therapy After the First 3 Months: Analysis of the STS-INTERMACS Database.

BACKGROUND: Left ventricular assist devices (LVADs) have been implanted as bridge to transplantation (BTT), bridge to candidacy (BTC) or destination therapy (DT) on the basis of relative and absolute contraindications to transplantation. Multiple factors may lead to changes in the strategy of support after LVAD implantation. METHODS: Based on INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) 2012-2020 data, 11,262 patients survived to 3 months on continuous-flow LVADs with intent of BTT or DT. Preimplant characteristics and early events post-LVAD were analyzed in relation to changes in BTT or DT strategy during the next 12 months. RESULTS: Among 3216 BTT patients at 3 months, later transplant delisting or death without transplant occurred in 536 (16.7%) and was more common with age, profiles 1-2, renal dysfunction, and independently for prior cardiac surgery (HR 1.25, 95% CI 1.04-1.51; P = 0.02). Post-LVAD events of infections, gastrointestinal bleeding, stroke, and right heart failure as defined by inotropic therapy, predicted delisting and death, as did in-hospital location at 3 months (HR 1.67, 95% CI 1.20-2.33; P = 0.0024). Of 8046 patients surviving to 3 months with the intent of destination therapy, 750 (9.3%) subsequently underwent listing or transplantation, often with initial histories of acute HF (HR 1.70, 95% CI 1.27-2.27; P = 0.0012) or malnutrition-cachexia (1.73, 95% CI 1.14-2.63; P = 0.0099). Multiple gastrointestinal bleeding events (≥ 4) with LVAD increased transition from BTT to DT (HR 4.22, 95% CI 1.46-12.275; P = 0.0078) but also from DT to BTT (HR 5.17, 95% CI 1.92-13.9; P = 0.0011). CONCLUSIONS: Implant strategies change over time in relation to preimplant characteristics and adverse events post implant. Preimplant recognition of factors predicting later change in implant strategy will refine initial triage, whereas further reduction of post-LVAD complications will expand options, including eventual consideration of heart transplantation.

Primary or Delayed Repair for Complete Atrioventricular Septal Defect, Tetralogy of Fallot, and Ventricular Septal Defect: Relationship to Country Economic Status.

OBJECTIVE: Primary repair in the first six months of life is routine for tetralogy of Fallot, complete atrioventricular septal defect, and ventricular septal defect in high-income countries. The objective of this analysis was to understand the utilization and outcomes of palliative and reparative procedures in high versus middle-income countries. METHODS: The World Database of Pediatric and Congenital Heart Surgery identified patients who underwent surgery for: tetralogy of Fallot, complete atrioventricular septal defect, and ventricular septal defect. Patients were categorized as undergoing primary repair, repair after prior palliation, or palliation only. Country economic status was categorized as lower middle, upper middle, and high, defined by the World Bank. Multiple logistic regression models were utilized to identify independent predictors of hospital mortality. RESULTS: Economic categories included high (n = 571, 5.3%), upper middle (n = 5,342, 50%), and lower middle (n = 4,793, 49.7%). The proportion of patients and median age with primary repair were: tetralogy of Fallot, 88.6%, 17.7 months; complete atrioventricular septal defect, 83.4%, 7.7 months; and ventricular septal defect, 97.1%, ten months. Age at repair was younger in high income countries (P < .0001). Overall mortality after repair was lowest in high income countries. Risk factors for hospital mortality included prematurity, genetic syndromes, and urgent or emergent operations (all P < .05). CONCLUSIONS: Primary repair was selected in >90% of patients, but definitive repair was delayed in lower and upper middle income countries compared with high-income countries. Repair after prior palliation versus primary repair was not a risk factor for hospital mortality. Initial palliation continues to have a small but important role in the management of these three specific congenital heart defects.

The Society of Thoracic Surgeons Intermacs 2023 Annual Report: Focus on Magnetically Levitated Devices.

The 14th Annual Report from The Society of Thoracic Surgeons (STS) Interagency Registry for Mechanically Assisted Circulatory Support (Intermacs) describes outcomes of 27,493 patients with a continuous-flow left ventricular assist device (LVAD) from the past decade (2013-2022). In 2022, 2517 primary LVADs were implanted, of which 2512 (99.8%) were fully magnetically levitated (Mag-Lev) devices. This shift to nearly exclusive use of a Mag-Lev device led us to examine its outcomes compared with contemporary (2018-2022) and historical (2013-2017) non-Mag-Lev cohorts. Patients supported by a Mag-Lev device (n = 10,920) had a higher 1- and 5-year survival of 86% (vs 79% and 81%, P < .0001) and 64% (vs 44% and 44%, P < .0001), respectively, than those receiving non-Mag-Lev devices during the contemporary and historical eras. Over 5 years, freedom from gastrointestinal bleeding (72% vs 60%, P < .0001), stroke (87% vs 67%, P < .0001), and device malfunction/pump thrombus (83% vs 54%, P < .0001), but not device-related infection (61% vs 64%, P = .93), was higher with Mag-Lev devices compared with non-Mag-Lev support during the contemporary era. In this large primacy cohort of real-world patients with advanced heart failure, this report underscores marked improvements in short- and intermediate-term survival and reduction of adverse events with a contemporary Mag-Lev LVAD.

Three decades of collaboration through the Pediatric Heart Transplant Society Registry: A journey through registry data with a highlight on children with single ventricle anatomy.

BACKGROUND: The Pediatric Heart Transplant Society (PHTS) Registry was founded 30 years ago as a collaborative effort among like-minded providers of this novel life-saving technique for children with end-stage heart failure. In the intervening decades, the data from the Registry have provided invaluable knowledge to the field of pediatric heart transplantation. This report of the PHTS Registry provides a comprehensive look at the data, highlighting both the longevity of the registry and one unique aspect of the PHTS registry, allowing for exploration into children with single ventricle anatomy. METHODS: The PHTS database was queried from January 1, 1993 to December 31, 2019 to include pediatric (age < 18 years) patients listed for HT. For our analysis, we primarily analyzed patients by era. The early era was defined as children listed for HT from January 1, 1993 to December 31, 2004; middle era January 1, 2005 to December 31, 2009; and recent era January 1, 2010 to December 31, 2019. Outcomes after listing and transplant, including mortality and morbidities, are presented as unadjusted for risk, but compared across eras. RESULTS: Since 1993, 11 995 children were listed for heart transplant and entered into the PHTS Registry with 9755 listed during the study period. The majority of listings occurred within the most recent era. Waitlist survival improved over the decades as did posttransplant survival. Other notable changes over time include fewer patients experiencing allograft rejection or infection after transplant. Waitlist and posttransplant survival have changed dramatically in patients with single ventricle physiology and significantly differ by stage of single ventricle palliation. SUMMARY: Key points from this PHTS Registry summary and focus on patients with single ventricle congenital heart disease in particular, include the changing landscape of candidates and recipients awaiting heart transplant. There is clear improvement in waitlist and transplant outcomes for children with both cardiomyopathy and congenital heart disease alike.

Seventh Annual Society of Thoracic Surgeons Pedimacs Report.

BACKGROUND: The Pediatric Interagency Registry for Mechanical Circulatory Support (Pedimacs), supported by The Society of Thoracic Surgeons, provides detailed information on pediatric patients supported with ventricular assist devices (VADs). METHODS: From September 19, 2012, to December 31, 2022, 1463 devices in 1219 patients aged <19 years were reported to the registry from 40 North American hospitals. RESULTS: Cardiomyopathy remains the most common underlying etiology (59%), followed by congenital heart disease (26%) and myocarditis (8%). Implantable continuous devices were most common (39%) type, followed by paracorporeal pulsatile (28%) and paracorporeal continuous (27%) devices. At 6 months after VAD implantation, a favorable outcome (transplant, recovery, or alive on device) was achieved in 85% of patients, which was greatest among those on implantable continuous VADs (92%) and least for paracorporeal continuous VADs (68%), although the patient population supported on these devices is different. CONCLUSIONS: This Seventh Pedimacs Report demonstrates the continued importance of VADs in the treatment of children. With the complexity of cardiac physiologies and sizes of patients, multiple types of devices are used, including paracorporeal continuous, paracorporeal pulsatile, and implantable continuous devices. The preoperative risk factors and differences in patient populations may account for some of the differences in survival observed among these devices. This report, along with other collaborative work, continues to advance the care of this challenging and vulnerable population.

Uncertain benefit of statins in pediatric heart transplant recipients: A PHTS analysis.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a leading cause of graft failure in pediatric heart transplant recipients (HTRs). Early statin use has been shown to reduce CAV incidence and all-cause mortality in adult HTRs. We sought to evaluate the contemporary prevalence and trends of statin use in pediatric HTRs and the association between statin use with CAV development and graft failure. METHODS: Patients aged <17 years at the time of primary heart transplant who survived to ≥3 years without CAV were identified from the Pediatric Heart Transplant Society database (2001-2018). Statin use in the first 3 years posttransplant was defined as consecutive, intermediate, or absent. Kaplan-Meier survival, multivariable modeling, and propensity score-matched analyses evaluated associations between statin use and CAV incidence and graft survival, with subanalyses performed on subjects aged ≥10 years at transplant. RESULTS: Among 3,485 (of which 1,086 aged ≥10 years) HTRs, 584 (17%) received consecutive statin therapy, 647 (19%) received intermediate use, and 2,254 (65%) received no statin therapy. Statin use varied widely between sites, with increasing use in the ≥10-year-old cohort over time. By multivariate analysis, statin use was not associated with graft loss. Consecutive statin use was also not associated with graft survival or freedom from CAV development when compared to absent statin use in unmatched or propensity-matched analyses. CONCLUSIONS: While statins remain commonly utilized in pediatric HTRs, early consecutive statin therapy did not decrease CAV incidence or graft loss. The differing effects of statins on CAV development and progression in pediatric vs adult HTRs suggest differing risk and mediating factors and require further study.

Risk factors for 1-year allograft loss in pediatric heart transplant patients using machine learning: An analysis of the pediatric heart transplant society database.

BACKGROUND: Pediatric heart transplant patients are at greatest risk of allograft loss in the first year. We assessed whether machine learning could improve 1-year risk assessment using the Pediatric Heart Transplant Society database. METHODS: Patients transplanted from 2010 to 2019 were included. The primary outcome was 1-year graft loss free survival. We developed a prediction model using cross-validation, by comparing Cox regression, gradient boosting, and random forests. The modeling strategy with the best discrimination and calibration was applied to fit a final prediction model. We used Shapley additive explanation (SHAP) values to perform variable selection and to estimate effect sizes and importance of individual variables when interpreting the final prediction model. RESULTS: Cumulative incidence of graft loss or mortality was 7.6%. Random forests had favorable discrimination and calibration compared to Cox proportional hazards with a C-statistic (95% confidence interval [CI]) of 0.74 (0.72, 0.76) versus 0.71 (0.69, 0.73), and closer alignment between predicted and observed risk. SHAP values computed using the final prediction model indicated that the diagnosis of congenital heart disease (CHD) increased 1 year predicted risk of graft loss by 1.7 (i.e., from 7.6% to 9.3%), need for mechanical circulatory support increased predicted risk by 2, and single ventricle CHD increased predicted risk by 1.9. These three predictors, respectively, were also estimated to be the most important among the 15 predictors in the final model. CONCLUSIONS: Risk prediction models used to facilitate patient selection for pediatric heart transplant can be improved without loss of interpretability using machine learning.

Outcomes After Hybrid Palliation for Infants With Critical Left Heart Obstruction.

BACKGROUND: Hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) is an initial management strategy for infants with critical left heart obstruction and serves as palliation until subsequent operations are pursued. OBJECTIVES: This study sought to determine patient characteristics and factors associated with subsequent outcomes for infants who underwent hybrid palliation. METHODS: From 2005 to 2019, 214 of 1,236 prospectively enrolled infants within the Congenital Heart Surgeons' Society's critical left heart obstruction cohort underwent hybrid palliation across 24 institutions. Multivariable hazard modeling with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan procedure, transplantation, or death. RESULTS: Preoperative comorbidities (eg, prematurity, low birth weight, genetic syndrome) were identified in 70% of infants (150 of 214). Median follow-up was 7 years, ranging up to 17 years. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had biventricular repair, 36% had Fontan procedure, 12% had transplantation, 35% died without surgical endpoints, and 8% were alive without an endpoint. Factors associated with transplantation were absence of ductal stent, older age, absent interatrial communication, smaller aortic root size, larger tricuspid valve area z-score, and larger left ventricular volume. Factors associated with death were low birth weight, concomitant genetic syndrome, cardiopulmonary bypass use during hybrid palliation, moderate to severe tricuspid valve regurgitation, and smaller ascending aortic size. CONCLUSIONS: Mortality remains high after hybrid palliation for infants with critical left heart obstruction. Nonetheless, hybrid palliation may facilitate biventricular repair for some infants and for others may serve as stabilization for intended functional univentricular palliation or primary transplantation.

The Academic Impact of Congenital Heart Surgeons' Society (CHSS) Studies.

PURPOSE: We reviewed all 64 articles ever published by The Congenital Heart Surgeons' Society (CHSS) Data Center to estimate the academic impact of these peer-reviewed articles. MATERIALS AND METHODS: The Congenital Heart Surgeons' Society has performed research based on 12 Diagnostic Inception Cohorts. The first cohort (Transposition) began enrolling patients on January 1, 1985. We queried PubMed to determine the number of publications that referenced each of the 64 journal articles generated by the datasets of the 12 Diagnostic Inception Cohorts that comprise the CHSS Database. Descriptive summaries of the data were tabulated using mean with standard deviation and median with range. RESULTS: Sixty-four peer-reviewed papers have been published based on the CHSS Database. Fifty-nine peer-reviewed articles have been published based on the 12 Diagnostic Inception Cohorts, and five additional articles have been published based on Data Science. Excluding the recently established Diagnostic Inception Cohort for patients with Ebstein malformation of tricuspid valve, the number of papers published per cohort ranged from 1 for coarctation to 11 for transposition of the great arteries. The 11 articles generated from the CHSS Transposition Cohort were referenced by a total of 111 articles (median number of references per journal article = 9 [range = 0-22, mean = 10.1]). Overall, individual articles were cited by an average of 11 (mean), and a maximum of 41 PubMed-listed publications. Overall, these 64 peer-reviewed articles based on the CHSS Database were cited 692 times in PubMed-listed publications. The first CHSS peer-reviewed article was published in 1987, and during the 35 years from 1987 to 2022, inclusive, the annual number of CHSS publications has ranged from 0 to 7, with a mean of 1.8 publications per year (median = 1, mode = 1). CONCLUSION: Congenital Heart Surgeons' Society studies are widely referenced in the pediatric cardiac surgical literature, with over 10 citations per published article. These cohorts provide unique information unavailable in other sources of data. A tool to access this analysis is available at: [https://data-center.chss.org/multimedia/files/2022/CAI.pdf].

John Kirklin's Impact on the Origins of Open Heart Surgery and the Congenital Heart Surgeons' Society.

John Kirklin stands out as one of the surgeons most identifiably responsible for bringing the field of open heart surgery to clinical reality and initiating scientific pursuits in the Congenital Heart Surgeons' Society. His accomplishments are perhaps best viewed in the context of other major contributions made by researchers and fellow surgeons, which collectively positioned Kirklin and other cardiac surgery pioneers to usher in the dawn of open heart surgery and later the Congenital Heart Surgeons' Society.

Widening care gap in VAD therapy.

BACKGROUND: The removal of the HeartWare ventricular assist device (HVAD) due to pump malfunctions and inferior outcomes compared to HeartMate 3 (HM3) in adults has created a care gap for younger patients. It is unclear if the reported HVAD survival differs by age and if the initial experience with HM3 can bridge the gap. METHODS: Using the Society of Thoracic Surgeons (STS) Intermacs and Pedimacs registries, durable ventricular assist device (VAD) implants between September 2012 and December 2021 were identified. Young adults (YA) were defined as <40 years old in Intermacs. Patients were excluded if they had an isolated right VAD (RVAD) or were implanted as destination therapy (DT). Survival analysis by Kaplan-Meier (KM) and competing outcomes curves was performed, and 1-year survival is reported. RESULTS: The Intermacs cohort consisted of YA (n = 1226; HVAD 818; HM3 408) with a median age of YA of 32.07 (26.66-36.27) years and weight (wt) of 83.2 (68-104.2) kg. Most had cardiomyopathy (CM) (92.2%). The Pedimacs cohort was 668 patients (median age 9.47 [1.82-14.23] years, wt 27.2 [10-57.05] kg), and most also had CM (70.5%). Device breakdown included HVAD (n = 326), Berlin EXCOR (n = 277), and HM3 (n = 65). HVAD survival differed by age in adults, with YA fairing better than adults >40 years old (88.8% vs 79.4% at 1 year, p < 0.0001). YA survival was also better compared to Pedimacs patient (88.9% vs 83.7%, p = 0.0002), but when competing events were analyzed, mortality was similar to YA (9.2% vs 9.6%, p = 0.1) with a higher proportion of patient undergoing transplant at 1 year in Pedimacs (74% vs 31.3%, p < 0.0001). Survival by device differed between HVAD and HM3 in YA (88.8% vs 94.4%, p = 0.0025). This difference in device survival was not seen in all children (83.7% vs 87.3%, p = 0.21), including those ≥25 kg. Adverse event profiles also differed across the groups with adults seeing less adverse events with the HM3, but the same was not found (including stroke) in the pediatric cohort. Survival outcomes for patients between 10 and 25 kg were similar with the HVAD compared to the Berlin Heart EXCOR (p = 0.4290), with similarities in stroke risk. CONCLUSION: The removal of the HVAD device may result in a care gap in younger patient whose survival outcomes do not mirror that of older adults. The HM3 can fill a portion of this gap with good survival, but there remains a subset of pediatric patients that, based on initial HM3 use, will no longer have access to intracorporeal support and therefore, despite reasonable outcomes with the Berlin Heart EXCOR, will not be able to be discharged home. Lastly, it is essential that future changes to the availability of devices take into account the various patient populations that utilize the device to avoid unintended consequences of access inequality.