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In adult patients, mechanical circulatory support (MCS) devices are part of the standard of care for heart failure. There are several options available that clinicians may use to provide support for their patients and thus the choice of devices can be tailored to their individual needs. Unfortunately, this is not the case for pediatric patients with heart failure, where the options for MCS modalities are far more limited because of size constraints and regulatory hurdles. Furthermore, the pathophysiology of heart failure in children is not identical to that of adults; thus, the device selection and configuration require different considerations. Management of pediatric patients on MCS requires a highly specialized team of pediatric professionals. The nurse caring for a child on MCS is an active participant in all aspects of the patient's care and must have an in-depth understanding of the patient's underlying physiology, the circulatory physiology of the MCS system, the reason for mechanical support, and the goal of support. [ABSTRACT FROM AUTHOR]

Objectives: For neonates and infants with aortic valve pathology, the Ross procedure historically has been associated with high rates of morbidity and mortality. Data regarding long-term durability are lacking., Methods: The international, multi-institutional Ross Collaborative included 6 tertiary care centers. Infants who underwent a Ross operation between 1996 and 2016 (allowing a minimum 5 years of follow-up) were retrospectively identified. Serial echocardiograms were examined to study evolution in neoaortic size and function., Results: Primary diagnoses for the 133 patients (n = 30 neonates) included isolated aortic stenosis (14%, n = 19), Shone complex (14%, n = 19), and aortic stenosis plus other (excluding Shone complex; n = 95, 71%), including arch obstruction (n = 55), left ventricular hypoplasia (n = 9), and mitral disease (moderate or greater stenosis or regurgitation, n = 31). At the time of the Ross procedure, median age was 96 days (interquartile range, 36-186), and median weight was 4.4 kg (3.6-6.5). In-hospital mortality occurred in 13 of 133 patients (10%) (4/30 [13%] neonates). Postdischarge mortality occurred in 10 of 120 patients (8%) at a median of 298 days post-Ross. Post-Ross neoaortic dilatation occurred, peaking at 4 to 5 SDs above normal at 2 to 3 years before returning to near-baseline z-score at a median follow-up of 11.5 [6.4-17.4] years. Autograft/left ventricular outflow tract reintervention was required in 5 of 120 patients (4%) at a median of 10.3 [4.1-12.8] years. Freedom from moderate or greater neoaortic regurgitation was 86% at 15 years., Conclusions: Neonates and infants experience excellent postdischarge survival and long-term freedom from autograft reintervention and aortic regurgitation after the Ross. Neoaortic dilatation normalizes in this population in the long-term. Increased consideration should be given to Ross in neonates and infants with aortic valve disease., Competing Interests: Conflict of Interest Statement The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (Copyright © 2024 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Pulmonary hypertension in children often progresses despite optimal therapy. This document provides an evidence-based clinical practice guideline for the management of children with progressive pulmonary hypertension despite optimal therapy., Methods: A multidisciplinary panel identified pertinent questions regarding the management of children with pulmonary hypertension that has progressed despite optimal therapy, conducted systematic reviews of the relevant literature, and applied the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to develop clinical recommendations., Results: After reviewing the research evidence, the panel considered the balance of desirable (benefits) and undesirable (harms and burdens) effects of the interventions in each proposed question. Valuation of our main outcomes was also considered, along with resources required, equity, acceptability, and feasibility. Recommendations were developed for or against interventional strategies specific to children with pulmonary hypertension that has progressed despite optimal therapy., Conclusions: Although there is a growing population of children with pulmonary hypertension, there is a striking lack of empirical evidence regarding management of those whose disease has progressed despite optimal pharmacotherapy. The panel formulated and provided the rationale for clinical recommendations for or against interventional strategies based on this limited empirical evidence, coupled with expert opinion, to aid clinicians in the management of these complex pediatric patients. In addition, we identified important areas for future research.

Background: Understanding of the hemostatic and complement alterations associated with cardiopulmonary bypass (CPB) in pediatric patients and the impact of these alterations on outcome is limited., Objectives: The present study prospectively characterized these alterations and their association with postoperative outcomes in pediatric CPB., Methods: All patients aged <21 years undergoing CPB at the authors' institution between 2020 and 2021 who weighed >3 kg, were >36 weeks gestational age, and had no known prothrombotic or hemorrhagic disorders were eligible. Blood samples were analyzed for multiple hemostatic and complement biomarkers pre-, intra-, and 24 hours post-CPB. Biomarker levels were compared to clinical outcomes, including chest tube output (CTO)., Results: Fifty consecutive patients were enrolled. CPB resulted in multiple significant alterations in hemostatic and complement components. Lower platelet counts (<80 × 10 9 platelets/L) at CPB termination were associated with increased postoperative CTO (P = .003). Lower factor (F)VIII levels (<60 IU/dL) at the end of CPB were associated with a longer hospital stay (P < .001) and increased postoperative CTO (P < .001). Patients undergoing staged single ventricle reconstruction were more likely to have lower platelet counts at CPB termination (P = .009) and higher CTO postoperatively (P = .001) than patients undergoing other types of surgical repair. These differences were not due to different preoperative platelet counts, increased incidences of circulatory arrest, or longer CPB times., Conclusion: These data suggest that intraoperative alterations in hemostatic system components may predict postoperative outcomes in pediatric CPB. Further study is needed to determine if interventions targeting platelets or FVIII could improve outcomes in pediatric CPB., Competing Interests: Declaration of competing interests K.T., S.J.H., J.S.T., J.A.R., E.M., M.G.B., L.R., B.F., B.K.S., A.L., C.S., M.K., D.L.S.M., and J.S.P. have no disclosures. The authors report that S. J. has performed consultancy for the following companies that is unrelated to the work presented here: Omeros, Sobi, and Alexion., (Copyright © 2024 International Society on Thrombosis and Haemostasis. Published by Elsevier Inc. All rights reserved.)

Competing Interests: Conflict of Interest Statement Dr Morales is a consultant for Abbott, Azyio, Berlin Heart, CorMatrix, Peca, Syncardia, and Xeltis, and a principal investigator for Food and Drug Administration trials sponsored by Peca, and Xeltis. All other authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

Adverse events (AEs) experienced by children and adults with congenital heart disease (CHD) on ventricular assist devices (VADs) are sometimes unique to these populations. The Advanced Cardiac Therapies Improving Outcomes Network (ACTION) and the Academic Research Consortium (ARC) aimed to harmonize definitions of pediatric and CHD AEs for use in clinical trials, registries, and regulatory evaluation. Data from the ACTION registry and adjudication committee were used to adapt general mechanical circulatory support ARC definitions. This ACTION-ARC international expert panel of trialists, clinicians, patients, families, statisticians, biomedical engineers, device developers, and regulatory agencies drafted and iterated definitions harmonized to ACTION data and existing literature during sessions conducted between December 2022 and May 2023, followed by dissemination across clinical/research audiences and professional organizations and further revision. Both email-linked, internet-based surveys and in-person discussions were used as a modified Delphi process. Nineteen AE types were identified and defined, including seven new event types and six event types that were deleted and will no longer be collected, achieving consensus. ACTION-ARC paired rigorous development with methodical stakeholder involvement and dissemination to define pediatric VAD AEs to facilitate assimilation of data across future clinical trials and evaluation of devices for VAD-supported children and adults with CHD., Competing Interests: Disclosure: A.L. is a consultant for Bayer, Abbott, Abiomed, Berlin Heart, and Syncardia and is the primary investigator for the Berlin ACTIVE driver trial. I.A. is a consultant for Abbott, Abiomed, Bivacor, and Berlin Heart. P.M.A.A. is Treasurer of the Board of Directors of the Extracorporeal Life Support Organization (ELSO) and immediate past-chair of PediECMO, a research collaborative between ELSO and the Pediatric Acute Lung Injury and Sepsis Investigators. P. Alexander’s institution received funding from the National Institutes of Health (NICHD R13HD104432) and the U.S. Department of Defense (U.S. DoD PRMRP Clinical Trial Award #W81XWH2210301). R.P.B. reports grants from the National Institutes of Health (NIH) R01 HL153519 and is a member of the Extracorporeal Life Support Organization (ELSO) Board of Directors. S.B. is a full-time employee of Abiomed, Inc. a part of Johnson and Johnson. K.B. is an Abbott employee. J.C. receives an unrestricted education grant—from Abbott and is a medical monitor for Pumpkin Trial. R.R.D. is a paid consultant for Abbott, Inc. and Abiomed, Inc. R.L.K. is an employee at Abbott, Inc. R.K. is an employee at Berlin Heart Inc. M.K. is involved in Grants & Consulting for Medtronic, Abbott Vascular, Johnson & Johnson, Boston Scientific, and Getinge. J.L. is a consultant for Abbott. D.L.S.M. is a consultant for Abbott Inc., Syncardia Inc., and Berlin Heart Inc. R.A.N. uses Berlin Heart of North America travel funds to attend the annual user’s group meeting. F.D.P. is a non-compensated ad-hoc scientific advisor for Abbott, BrioHealth Solutions, FineHeart, and Medtronic, a non-compensated medical monitor for Abiomed, a member—Data Safety Monitoring Board for Carmat, receives grant funding from the National Heart, Lung, and Blood Institute and the Agency for Healthcare Research and Quality, and receives partial salary support from Blue Cross/Blue Shield of Michigan as Associate Director of the Michigan Society of Thoracic and Cardiovascular Surgeons Quality Collaborative. D.M.P. is on the Data Safety Monitoring Board for the Berlin Active Driver Trial. D.R. is associated with ACTION, DSMB for Parexel (unrelated to topic of AE manuscript), and Medicolegal consultation (unrelated to topic of AE manuscript). J.W.R. is a consultant for American Regent, AskBio, BioMarin, Bayer, Merck, Bristol Myers Squibb, and Enzyvant. E.S. reports institutional contracts for which he receives no direct compensation with Boston Scientific, Cardiawave, Edwards Lifesciences, Medtronic, Shanghai Microport Medical Co. Ltd., NVT GmBH, Pie Medical Imaging, Siemens Healthcare GmBH. M.E.S. is involved in a Medtronic educational contract, Octapharma advisory panel, and NIH DSMB for PumpKIN trial (completed). J.M.T. is a Berlin Heart CEC member. C.V. is on the Merck scientific advisory committee and a consultant for Abiomed. C.R.V. is a consultant for PTC therapeutics (previous), Antisense (current), and Capricor (current). The other authors have no conflicts of interest to report., (Copyright © ASAIO 2024.)

Background: With significant advancements in fetal cardiac imaging, patients with complex congenital heart disease (CHD) carrying a high risk for postnatal demise are now being diagnosed earlier. We sought to assess an interdisciplinary strategy for delivering these children in an operating room (OR) adjacent to a cardiac OR for immediate surgery or stabilization. Methods: All children prenatally diagnosed with CHD at risk for immediate postnatal hemodynamic instability and cardiogenic shock who were delivered in the operating room (OR) between 2012 and 2023 in which the senior author was consulted were included. Results: Eight patients were identified. Six (75%) patients were operated on day-of-life zero, all requiring obstructed total anomalous pulmonary venous return (TAPVR) repair. Of these six patients, 2 (33%) required a simultaneous Norwood procedure, 2 (33%) required pulmonary artery unifocalization and modified Blalock-Taussig-Thomas shunt, and 2 (33%) patients had repair of obstructed mixed TAPVR. The remaining 2 patients potentially planned for immediate surgery had nonimmune hydrops fetalis and went into cardiogenic shock at 12 and 72 hours postnatally, requiring a novel Norwood procedure with left-ventricular exclusion for severe aortic/mitral valve insufficiency. The median ventilation and inpatient durations were 19 [IQR: 11-26] days and 41 [IQR: 32-128] days, respectively. Three(38%) patients required one or more in-hospital reoperations. Subsequent staged procedures included Glenn (n = 5), Fontan (n = 3), biventricular repair (n = 2), ventricular assist device placement (n = 1), and heart transplant (n = 1). Median follow-up was 5.7 [IQR:1.3-7.8] years. The five-year postoperative survival was 88% (n = 7/8). Conclusion: While children with these diagnoses have historically had poor survival, the strategy of birth in the OR adjacent to a cardiac OR where emergent surgery is planned is a potentially promising strategy with excellent clinical outcomes. However, this is a high-resource strategy whose feasibility in any program requires thoughtful assessment., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Morales is a consultant for Abbott, Inc., Azyio, Inc., Berlin Heart, Inc., CorMatrix, Inc., Peca, Inc., Syncardia, Inc., and Xeltis, Inc. Dr Ashfaq is a consultant for PyrAmes, Inc.

Background: Partial heart transplantation (PHT) is a novel procedure for children in need of a growing valve replacement option. One challenge is identifying suitable donor valves. Semilunar heart valves from patients receiving a retransplant may be a source, however their functionality and growth potential especially at the time of retransplant are unknown. We aimed to assess growth and function of these valves., Methods: Data from patients undergoing a retransplant at a single institution were analyzed. Echocardiograms were compared following the primary transplant and immediately before retransplant to assess growth and valve function., Results: Thirteen patients were included. Recipient and donor ages at the primary transplant were median (range): 2 years (0-13) and 3 years (0-40), respectively. The median time to retransplant was 11 years (2-21). There was an overall growth across all semilunar valve measurements; aortic valve annulus diameter (mean increase ± standard deviation): 0.2 ± 0.12 cm, aortic root: 0.29 ± 0.16 cm, and pulmonary valve annulus: 0.5 ± 0.34 cm; all p < 0.05. The growth rate of valves was higher in younger patients and showed a better correlation with graft age relative to recipient age: aortic valve annulus growth R 2 : 0.61 (graft age) versus 0.54 (recipient age); aortic root R 2 : 0.73 versus 0.57; pulmonary valve annulus R 2 : 0.94 versus 0.86. No patients had clinically significant regurgitation or stenosis on the latest echocardiogram. All except one patient's measurement had valve Z-scores within ±2 at retransplant., Conclusion: Explanted hearts from patients undergoing retransplantation could be considered an additional source of semilunar valves for PHT. Valves from these hearts were found to function normally and grew in proportion with the recipient's body. Valves from younger donors/recipients demonstrated a more rapid growth rate., (© 2025 Wiley Periodicals LLC.)

Background: Elevated renin has been shown to predict poor response to standard vasoactive therapies and is associated with poor outcomes in adults. Similarly, elevated renin was associated with mortality in children with septic shock. Renin concentration profiles after pediatric cardiac surgery are unknown. The purpose of this study was to characterize renin kinetics after pediatric cardiac surgery., Methods: Single-center retrospective study of infants who underwent cardiac surgery with cardiopulmonary bypass (CPB) utilizing serum samples obtained in the perioperative period to measure plasma renin concentrations (pg/mL). Time points included pre-bypass and 1, 4, and 24 h after initiation of CPB., Results: Fifty patients (65% male) with a median age 5 months (interquartile range (IQR) 3.5, 6.5) were included. Renin concentrations peaked 4 h after CPB. There was a significant difference in preoperative and 4 h post-CPB renin concentration (4 h post-CPB vs preoperative: mean difference 100.6, 95% confidence interval (CI) 48.9-152.4, P  < .001). Median renin concentration at 24 h after CPB was lower than the preoperative baseline., Conclusions: We describe renin kinetics in infants after CPB. Future studies based on these data can now be performed to evaluate the associations of elevated renin concentrations with adverse outcomes., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Competing Interests: Conflict of Interest Statement Dr Morales is a consultant for Abbott Laboratories, Azyio Biologics, Berlin Heart, CorMatrix Cardiovascular, Peca Labs, Syncardia Systems, and Xeltis, and a principal investigator for Food and Drug Administration trials sponsored by Peca Labs and Xeltis. All other authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

Objective: Donation after circulatory death (DCD) lung transplantation has increased, but there is limited data in children. We sought to characterize the international experience of pediatric DCD lung transplant (LT) in comparison to donation after brain death (DBD) to address extreme donor organ shortages in children needing LT., Methods: Using the International Society for Heart and Lung Transplantation (ISHLT) Thoracic Organ Transplant Registry, 1453 children (<18yo) LT recipients from January 2004 to June 2018 were identified: 34 (3%) were DCD and 1419 (97%) were DBD recipients. Post-transplant outcomes were compared between groups. Propensity score method was used to derive matched cohorts and were compared between groups., Results: DCD and DBD recipients were of similar age, with cystic fibrosis being the most frequent indication for LT in both groups (64.5% vs. 57.5%, respectively). Kaplan-Meier analysis demonstrated similar survival between DCD and DBD cohorts, whereas propensity score-matched recipients also identified similar post-transplant survival in both groups (P=0.098). Secondary analysis found that DCD LT recipients had a longer post-transplant length of hospital stay (unmatched cohorts: 36.5d vs. 20d, p=0.022; matched cohort: 26d vs. 19d, p=0.016), and shorter time to acute cellular rejection (ACR) (unmatched cohorts: 248d vs. 560d, p=0.039; matched cohorts: 248d vs. 1650d,p=0.059)., Conclusions: Due to DCD being a key contributor to the increasing number of lung transplants being performed worldwide, the results of this analysis support this organ donation approach in children requiring LT, which would increase access to donor organs. The identification of a potential shorter time to ACR needs further exploration as more DCD pediatric LTs are performed.

Background: There is an increasing prevalence of durable mechanical circulatory supported patients in both the in-and-out of hospital communities. The scientific literature regarding the approach to patients supported by durable mechanical circulatory devices who suffer acutely impaired perfusion has not been well explored., Methods: The International Liaison Committee on Resuscitation Advanced, Basic, and Pediatric Life Support Task Forces conducted a scoping review of the literature using a population, context, and concept framework., Results: A total of 32 publications that included patients who were receiving durable mechanical circulatory support and required acute resuscitation were identified. Most of the identified studies were case reports or small case series. Of these, 11 (34.4%) included patients who received chest compressions. A number of studies reported upon delays in the application of chest compressions resulting from complexity due to the expected pulselessness in some patients with continuous flow left-ventricular assist devices as well as from concern regarding potential dislodgement of the mechanical circulatory support device. Three observational studies identified worse outcomes in durable mechanical circulatory support receiving patients with cardiac arrest and acutely impaired perfusion who received chest compressions as compared to those who did not, however those studies were at high risk of bias. Of 226 patients across 11 studies and two published scientific abstracts who sustained cardiac arrest while supported by durable MCS and underwent chest compressions, there were no reported instances of device dislodgement and 71 (31.4%) patients had favorable outcomes., Conclusions: There is a scarcity of evidence to inform the resuscitation of patients with durable mechanical circulatory support (MCS) experiencing acute impairment in perfusion and cardiac arrest. Reports indicate that delays in resuscitation often stem from rescuers' uncertainty about the safety of administering chest compressions. Notably, no instances of device dislodgement have been documented following chest compressions, suggesting that the risk of harm from timely CPR in these patients is minimal., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: ‘All ILCOR task force members complete annual conflict of interest disclosures, and conflict of interest was managed per ILCOR guidelines. All authors external to ILCOR completed a conflicts of interest disclosure.’, (Copyright © 2024 Elsevier B.V. All rights reserved.)

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., Competing Interests: Disclosures Joseph Rossano reports a relationship with Bayer Corporation that includes: consulting or advisory; with Merck & Co Inc that includes: consulting or advisory; with Cytokinetics Inc that includes: consulting or advisory; with Bristol-Myers Squibb Co that includes: consulting or advisory; and with American Regent Inc that includes: consulting or advisory. James Kirklin reports a relationship with The Society of Thoracic Surgeons that includes: employment. David Morales reports a relationship with Abbott that includes: consulting or advisory; with Azyio that includes: consulting or advisor; with Xeltis BV that includes: consulting or advisory; with Berlin Heart GmbH that includes: consulting or advisory; with CorMatrix Cardiovascular Inc that includes: consulting or advisory; and with SynCardia Systems LLC that includes: consulting or advisory. The other authors have no conflicts of interest to disclose., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Stroke affects surgical decision making and outcomes of neonatal cardiac surgery (CHS). We sought to assess the burden of stroke in this population from a large multicenter database., Methods: We analyzed neonates undergoing CHS with cardiopulmonary bypass from the Pediatric Health Information System database (2004-2022). The cohort was divided into the stroke group, which included preoperative/postoperative ischemic, hemorrhagic subtypes, and grade III to IV intraventricular hemorrhages, and compared in-hospital and follow-up outcomes to a nonstroke group., Results: A perioperative stroke occurred in 800 of 14,228 neonates (5.6%). The stroke group was more likely to have hypoplastic left heart syndrome (HLHS; 30.5% vs 20.7%), born preterm (19.4% vs 11.7%), low birth weight (17.8% vs 11.9%), and require extracorporeal membrane oxygenation (ECMO; 48.8% vs 13.8%; all P < .001). Outcomes comparing stroke vs no stroke were mortality, 33.1% vs 8.9%; nonhome discharge, 12.5% vs 6.9%; length of stay, 41 vs 24 days; and hospitalization costs, $354,521 vs $180,489 (all, P < .05). Stroke increased the odds of mortality by 2-fold (odds ratio, 2.20; 95% CI, 1.75-2.77; P < .001) after adjusting for ECMO, prematurity among other significant factors. On follow-up, the stroke group had a higher incidence of hydrocephalus (9.5% vs 1.3%), cerebral palsy (6.2% vs 1.3%), and autism spectrum disorder (7.1% vs 3.5%), and survivors of the index admission had higher 1- and 5-year mortality (5.3% and 11.3% vs 3.3% and 5.9%, respectively; all P < .05)., Conclusions: Neonatal CHS patients born prematurely, diagnosed with HLHS, or those requiring ECMO are disproportionately affected by stroke. The occurrence of stroke is marked by significantly higher mortality. Future research should seek to identify factors leading to stroke to increase rescue after stroke and for improvement of long-term outcomes., Competing Interests: Disclosures Awais Asfaq reports a relationship with PyrAmes as a primary investigator. David Morales reports consulting or advisory relationships with Abbott Vascular, Aziyo, Xeltis BV, Berlin Heart, and SynCardia Systems. The other authors have no conflicts of interest to disclose., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

After Fontan operation, decreased venous capacitance and venoconstriction are adaptive mechanisms to maintain venous return and cardiac output. The consequent higher venous pressure may adversely impact end-organ function, exercise capacity and result in worse clinical outcomes. This pilot study evaluated the safety and effect of isosorbide dinitrate (ISDN), a venodilator, on exercise capacity, peripheral venous pressure (PVP), and liver stiffness in patients with Fontan circulation. In this prospective single-arm trial, 15 individuals with Fontan circulation were evaluated at baseline and after 4 weeks of therapeutic treatment with ISDN. Primary aims were to assess the safety of ISDN and the effect on maximal exercise. We also aimed to evaluate the effect of ISDN on ultrasound-assessed liver stiffness, markers of submaximal exercise, and PVP at rest and peak exercise. Repeated measures t-tests were used to assess change in variables of interest in response to ISDN. Mean age was 23.5 ± 9.2 years (range 11.2-39.0 years), and 10/15 (67%) were male. There was no statistically significant change in peak VO 2 (1401 ± 428 to 1428 ± 436 mL/min, p = 0.128), but VO 2 at the anaerobic threshold increased (1087 ± 313 to 1115 ± 302 mL/min, p = 0.03). ISDN was also associated with a lower peak exercise PVP (22.5 ± 4.5 to 20.6 ± 3.0 mmHg, p = 0.015). Liver stiffness was lower with ISDN, though the difference was not statistically significant (2.3 ± 0.4 to 2.1 ± 0.5 m/s, p = 0.079). Of the patients completing the trial, mild headache was common (67%), but there were no major adverse events. Treatment with ISDN for 4 weeks is well-tolerated in patients with a Fontan circulation. ISDN is associated with an increase in VO 2 at anaerobic threshold, lower peak PVP, and a trend toward lower liver stiffness. Larger, longer duration studies will be necessary to define the impact of ISDN on clinical outcomes in the Fontan circulation.Clinical Trial Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT04297241., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Extracorporeal membrane oxygenation (ECMO) is often associated with disturbances in acid/base status that can be triggered by the underlying pathology or the ECMO circuit itself. Extracorporeal membrane oxygenation is known to cause hypocapnia, but the impact of reduced partial pressure of carbon dioxide (pCO 2 ) on biomarkers of tissue perfusion during veno-arterial (VA)-ECMO has not been evaluated. To study the impact of low pCO 2 on perfusion indices in VA-ECMO, we placed Sprague-Dawley rats on an established VA-ECMO circuit using either an oxygen/carbon dioxide mixture (O 2 95%, CO 2 5%) or 100% O 2 delivered through the oxygenator (n = 5 per cohort). Animals receiving 100% O 2 developed a significant VA CO 2 difference (pCO 2 gap) and rising blood lactate levels that were inversely proportional to the decrease in pCO 2 values. In contrast, pCO 2 gap and lactate levels remained similar to pre-ECMO baseline levels in animals receiving the O 2 /CO 2 mixture. More importantly, there was no significant difference in venous oxygen saturation (SvO 2 ) between the two groups, suggesting that elevated blood lactate levels observed in the rats receiving 100% O 2 were a response to oxygenator induced hypocapnia and alkaline pH rather than reduced perfusion or underlying tissue hypoxia. These findings have implications in clinical and experimental extracorporeal support contexts., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2024.)

Background: Children who undergo cardiac surgery may require postcardiotomy extracorporeal membrane oxygenation (ECMO). Although morbidities are considerable, our understanding of outcome determinants is limited. We evaluated associations between patient and perioperative factors with outcomes., Methods: The Society of Thoracic Surgeons Congenital Heart Surgery Database was queried for patients aged <18 years old who underwent postcardiotomy ECMO from January 2016 through June 2021. The primary outcome was survival to hospital discharge. The secondary outcome was survival without neurologic injury. Logistic regression for binary outcomes and competing risk analysis for survival were used to identify the most important predictors. Variables were selected by stepwise procedure using entry level P = .35. Those with P ≤ .1 were kept in the final model., Results: Postcardiotomy ECMO was used to support 3181 patients during the same hospitalization as cardiac surgery: (A) intraoperative initiation of ECMO, n = 1206; (B) early postoperative (≤48 hours), n = 936; and (C) late postoperative (>48 hours), n = 1039. The most common primary procedure of the index operation was the Norwood procedure. Of those with intraoperative ECMO, 57% survived to discharge vs 59% with early postoperative ECMO and 42% late postoperative ECMO (χ 2 (2)  = 64, P < .0001, V = 0.14). In all groups, postoperative septicemia, cardiac arrest, and new neurologic injury had the strongest association with mortality, whereas postoperative reintubation and unplanned noncardiac reoperation were associated with higher survival., Conclusions: Multiple risk factors impact survival in children who undergo cardiac surgery and postcardiotomy ECMO. ECMO initiated >48 hours after surgery is associated with the poorest outcomes. This is the first step in creating a predictive tool to educate clinicians and families regarding expectations in this high-risk population., Competing Interests: Disclosures Farhan Zafar reports a relationship with TransMedics Inc that includes: employment. David S. Cooper reports a relationship with Mallinckrodt LLC that includes: consulting or advisory and with Prolacta Bioscience Inc that includes: speaking and lecture fees. Ravi Thiagarajan reports a relationship with Extracorporeal Life Support Organization that includes: speaking and lecture fees and with the Society of Critical Care Medicine that includes: speaking and lecture fees. Jeffrey P. Jacobs reports a relationship with American Academy of Dermatology that includes: consulting or advisory and with SpecialtyCare that includes: consulting or advisory. Iki Adachi reports a relationship with Nipro Corporation that includes: speaking and lecture fees. Katsuhide Maeda reports a relationship with Abbott that includes: consulting or advisory and with Peca Labs that includes: consulting or advisory. David L.S. Morales reports a relationship with Abbott that includes: consulting or advisory; with Peca Labs that includes: consulting or advisory; with Berlin Heart that includes: consulting or advisory; and with SynCardia Systems LLC that includes: consulting or advisory. The other authors have no conflicts of interest to disclose., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Data on concomitant cardiac surgery (CCS) performed during pediatric lung transplantation (LTx) is limited. Therefore, we conducted a multi-institutional analysis to identify the incidence and outcomes of CCS in pediatric (< 18 years) LTx recipients by merging data (2004-2023) from the United Network for Organ Sharing (UNOS) and Pediatric Health Information System (PHIS) databases. Of the total of 596 pediatric LTx recipients, 87 (15%) underwent CCS. The majority of these cardiac surgeries were atrial septal defect (ASD) closure (90%) followed by aortic arch/descending aortic repair (3%), atrial repair (3%), ventricular septal defect closure (2%), patent ductus arteriosus ligation (2%), and tricuspid valve repair (2%). The median age at LTx was 3 years (IQR: 0-12). Pulmonary hypertension (PHT) was the predominant indication for LTx (54%). Survival to discharge was 94% and 5-years survival was 64%. Our findings indicate CCS in children undergoing LTx has acceptable outcomes., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Patients with heterotaxy syndrome and congenital heart disease (CHD) experience inferior cardiac surgical outcomes. Heart transplantation outcomes are understudied, however, particularly compared to non-CHD patients. Data from UNOS and PHIS were used to identify 4803 children (< 18 years) undergoing first-time heart transplant between 2003 and 2022 with diagnoses of heterotaxy (n = 278), other-CHD (n = 2236), and non-CHD cardiomyopathy (n = 2289). Heterotaxy patients were older (median 5 yr) and heavier (median 17 kg) at transplant than other-CHD (median 2 yr and 12 kg), and younger and lighter than cardiomyopathy (median 7 yr and 24 kg) (all p < 0.001). UNOS status 1A/1 at listing was not different between groups (65-67%; p = 0.683). At transplant, heterotaxy and other-CHD patients had similar rates of renal dysfunction (12 and 17%), inotropes (10% and 11%), and ventilator-dependence (19 and 18%). Compared to cardiomyopathy, heterotaxy patients had comparable renal dysfunction (9%, p = 0.058) and inotropes (46%, p = 0.097) but more hepatic dysfunction (17%, p < 0.001) and ventilator-dependence (12%, p = 0.003). Rates of ventricular assist device (VAD) were: heterotaxy-10%, other-CHD-11% (p = 0.839 vs. heterotaxy), cardiomyopathy-37% (p < 0.001 vs. heterotaxy). The 1-year incidence of acute rejection post-transplant was comparable between heterotaxy and others (p > 0.05). While overall post-transplant survival was significantly worse for heterotaxy than others (p < 0.05 vs. both), conditional 1-year survival was comparable (p > 0.3 vs. both). Children with heterotaxy syndrome experience inferior post-heart transplant survival, although early mortality appears to influence this trend, with 1-year survivors having equivalent outcomes. Given similar pre-transplant clinical status to others, heterotaxy patients are potentially under risk-stratified. Increased VAD utilization and pre-transplant end-organ function optimization may portend improved outcomes., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Pediatric lung transplantation represents a treatment option for children with advanced lung disease or pulmonary vascular disorders who are deemed an appropriate candidate. Pediatric flexible bronchoscopy is an important and evolving field that is highly relevant in the pediatric lung transplant population. It is thus important to advance our knowledge to better understand how care for children after lung transplant can be maximally optimized using pediatric bronchoscopy. Our goals are to continually improve procedural skills when performing bronchoscopy and to decrease the complication rate while acquiring adequate samples for diagnostic evaluation. Attainment of these goals is critical since allograft assessment by bronchoscopic biopsy is required for histological diagnosis of acute cellular rejection and is an important contributor to establishing chronic lung allograft dysfunction, a common complication after lung transplant. Flexible bronchoscopy with bronchoalveolar lavage and transbronchial lung biopsy plays a key role in lung transplant graft assessment. In this article, we discuss the application of bronchoscopy in pediatric lung transplant evaluation including historical approaches, our experience, and future directions not only in bronchoscopy but also in the evolving pediatric lung transplantation field. Pediatric flexible bronchoscopy has become a vital modality for diagnosing lung transplant complications in children as well as assessing therapeutic responses. Herein, we review the value of flexible bronchoscopy in the management of children after lung transplant and discuss the application of novel techniques to improve care for this complex pediatric patient population and we provide a brief update about new diagnostic techniques applied in the growing lung transplantation field., (© 2024 The Authors. Pediatric Transplantation published by Wiley Periodicals LLC.)

Objective: Ventricular assist devices (VADs) and inotropes are feasible modalities to bridge children to heart transplant (HT) in outpatient settings. However, it is unclear which modality yields superior clinical status at HT and posttransplant survival., Methods: The United Network for Organ Sharing was used to identify patients aged 18 years or younger, weighing >25 kg, from 2012 to 2022 who were outpatients at HT (n = 835). Patients were grouped by bridging modality at HT: VAD (n = 235 [28%]), inotropes (n = 176 [21%]), or neither (no support) (n = 424 [50%])., Results: VAD patients were of similar age (P = .260) but heavier (P = .007) and more likely to have dilated cardiomyopathy (P < .001) than their inotrope counterparts. VAD patients had similar clinical status at HT but superior functional status (performance scale >70%) (59% vs 31%) (P < .001). Overall posttransplant survival in VAD patients (1-year and 5-year survival, 97% and 88%, respectively) was comparable to patients with no support (93% and 87%, respectively) (P = .090) and those on inotropes (98% and 83%, respectively) (P = .089). One-year conditional survival was superior for VAD vs inotrope (2-year and 6-year survival, 96% and 91%, respectively vs 97% and 79%, respectively) (P = .030) and 5-year conditional survival for VAD patients was superior to inotrope (7-year and 10-year survival, 100% and 100%, respectively vs 100% and 88%, respectively) (P = .022) and no support (100% and 83%, respectively) (P = .011)., Conclusions: Consistent with prior studies, short-term outcomes for pediatric patients bridged to HT in the outpatient setting with VAD or inotropes is excellent. However, compared with outpatients bridged to HT on inotropes, outpatient VAD support allowed for better functional status at HT and superior late posttransplant survival., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Junctional ectopic tachycardia (JET) complicates congenital heart surgery in 2% to 8.3% of cases. JET is associated with postoperative morbidity in single-center studies. We used the Pediatric Cardiac Critical Care Consortium data registry to provide a multicenter epidemiologic description of treated JET., Methods: This is a retrospective study (February 2019-August 2022) of patients with treated JET. Inclusion criteria were (1) <12 months old at the index operation, and (2) treated for JET <72 hours after surgery. Diagnosis was defined by receiving treatment (pacing, cooling, and medications). A multilevel logistic regression analysis with hospital random effect identified JET risk factors. Impact of JET on outcomes was estimated by margins/attributable risk analysis using previous risk-adjustment models., Results: Among 24,073 patients from 63 centers, 1436 (6.0%) were treated for JET with significant center variability (0% to 17.9%). Median time to onset was 3.4 hours, with 34% present on admission. Median duration was 2 days (interquartile range, 1-4 days). Tetralogy of Fallot, atrioventricular canal, and ventricular septal defect repair represented >50% of JET. Patient characteristics independently associated with JET included neonatal age, Asian race, cardiopulmonary bypass time, open sternum, and early postoperative inotropic agents. JET was associated with increased risk-adjusted durations of mechanical ventilation (incidence rate ratio, 1.6; 95% CI, 1.5-1.7) and intensive care unit length of stay (incidence rate ratio, 1.3; 95% CI, 1.2-1.3), but not mortality., Conclusions: JET is treated in 6% of patients with substantial center variability. JET contributes to increased use of postoperative resources. High center variability warrants further study to identify potential modifiable factors that could serve as targets for improvement efforts to ameliorate deleterious outcomes., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: Many pediatric Fontan patients require heart transplant, but this cohort is understudied given the difficulty in identifying these patients in national registries. We sought to characterize survival post-transplant in a large cohort of pediatric patients undergoing the Fontan., Methods: The United Network for Organ Sharing and Pediatric Health Information System were used to identify Fontan heart transplant recipients aged less than 18 years (n = 241) between 2005 and 2022. Decompensation was defined as the presence of extracorporeal membrane oxygenation, ventilation, hepatic/renal dysfunction, paralytics, or total parenteral nutrition at transplant., Results: Median age at transplant was 9 (interquartile range, 5-12) years. Median waitlist time was 107 (37-229) days. Median volume across 32 center was 8 (3-11) cases. Approximately half (n = 107, 45%) of recipients had 1A/1 initial listing status. Sixty-four patients (28%) were functionally impaired at transplant, 10 patients (4%) were ventilated, and 18 patients (8%) had ventricular assist device support. Fifty-nine patients (25%) had hepatic dysfunction, and 15 patients (6%) had renal dysfunction. Twenty-one patients (9%) were dependent on total parenteral nutrition. Median postoperative stay was 24 (14-46) days, and in-hospital mortality was 7%. Kaplan-Meier analysis showed 1- and 5-year survivals of 89% (95% CI, 85-94) and 74% (95% CI, 81-86), respectively. Kaplan-Meier of Fontan patients without decompensation (n = 154) at transplant demonstrated 1- and 5-year survivals of 93% (95% CI, 88-97) and 88% (95% CI, 82-94), respectively. In-hospital mortality was higher in decompensated patients (11% vs 4%, P = .023). Multivariable analysis showed that decompensation predicted worse post-transplant survival (hazard ratio, 2.47; 95% CI, 1.16-5.22; P = .018), whereas older age at transplant predicted superior post-transplant survival (hazard ratio, 0.89/year; 95% CI, 0.80-0.98; P = .019)., Conclusions: Pediatric Fontan post-transplant outcomes are promising, although early mortality remains high. For nondecompensated pediatric patients at transplant without end-organ disease (>63% of cohort), early mortality is circumvented and post-transplant survival is excellent and similar to all pediatric transplantation., Competing Interests: Conflict of Interest Statement D.L.S.M. is a consultant for Abbott, Inc, Azyio, Inc, Berlin Heart, Inc, CorMatrix, Inc, Peca, Inc, Syncardia, Inc, and Xeltis, Inc, and serves as a principal investigator for Food and Drug Administration trials sponsored by Peca, Inc, and Xeltis, Inc. F.Z. has a financial relationship (employment) with TransMedics, Inc. All other authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Associations between social determinants of health (SDOH) and adverse outcomes for children with congenital heart disease (CHD) are starting to be recognized; however, such links remain understudied. We examined the relationship between community-level material deprivation on mortality, readmission, and length of stay (LOS) for children undergoing surgery for CHD. We performed a retrospective cohort study of patients who underwent cardiac surgery at our institution from 2015 to 2018. A community-level deprivation index (DI), a marker of community material deprivation, was generated to contextualize the lived experience of children with CHD. Generalized mixed-effects models were used to assess links between the DI and outcomes of mortality, readmission, and LOS following cardiac surgery. The DI and components were scaled to provide mean differences for a one standard deviation (SD) increase in deprivation. We identified 1,187 unique patients with surgical admissions. The median LOS was 11 days, with an overall mortality rate of 4.6% and readmission rate of 7.6%. The DI ranged from 0.08 to 0.85 with a mean of 0.37 (SD 0.12). The DI was associated with increased LOS for patients with more complex heart disease (STAT 3, 4, and 5), which persisted after adjusting for factors that could prolong LOS (all p < 0.05). The DI approached but did not meet a significant association with mortality (p = 0.0528); it was not associated with readmission (p = 0.36). Community-level deprivation is associated with increased LOS for patients undergoing cardiac surgery. Future work to identify the specific health-related social needs contributing to LOS and identify targets for intervention is needed., (© 2024. The Author(s).)

Congenital heart disease (CHD) is a well-established risk factor for inferior waitlist and post-heart transplant survival in children. Differences in outcomes between CHD subgroups are understudied. The present study compared outcomes for palliated hypoplastic left heart syndrome (HLHS) patients to other non-single ventricle CHD (non-SVCHD) and non-CHD patients. United Network for Organ Sharing was used to identify children (age < 18) listed for heart transplant in the United States between 2016 and 2021. CHD sub-diagnoses were only available for United Network for Organ Sharing status 1a after 2015, thereby defining the cohort. Waitlist outcomes were studied using competing-risk time-to-event analysis for transplantation, mortality/decompensation, and alive-on-waitlist. Multivariable Cox proportional hazards regression analyses were used to identify factors associated with inferior post-transplant survival. Patients included: palliated-HLHS (n = 477), non-SVCHD (n = 686), and non-CHD (n = 1261). At listing, Palliated-HLHS patients were older than non-SVCHD (median 2-year [IQR 0-8] vs median 0-year [0-3], respectively) and younger than non-CHD (median 7-year [0-14]) (P < 0.001 vs both), and were more likely to be white (P < 0.01 vs both). Upon time-to-event analysis, rates of waitlist mortality/decompensation rates were greater among non-SVCHD than palliated-HLHS. Post-transplant survival was comparable between palliated-HLHS and non-SVCHD (P = 0.920) but worse compared to non-CHD (P < 0.001). Both palliated-HLHS (HR 2.40 [95% CI 1.68-3.42]) and non-SVSCHD (2.04 [1.39-2.99]) were independently associated with post-transplant mortality. Palliated-HLHS patients with heart failure experience significantly worse post-transplant outcomes than non-CHD but, compared to other CHD patients, experience superior waitlist and comparable post-transplant survival. While a high-risk cohort, HLHS patients can achieve gratifying waitlist and post-transplant survival., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objectives: Ventricular assist devices (VADs) are associated with a mortality benefit in children. Database-driven analyses have associated VADs with reduction of modifiable risk factors (MRFs), but validation with institutional data is required. The authors studied MRF reduction on VAD and the influence of persistent MRFs on survival after heart transplant., Methods: All patients at the authors' institution requiring a VAD at transplant (2011-2022) were retrospectively identified. MRFs included renal dysfunction (estimated glomerular filtration rate <60 mL/min/1.73 m 2 ), hepatic dysfunction (total bilirubin ≥1.2 mg/dL), total parenteral nutrition dependence, sedatives, paralytics, inotropes, and mechanical ventilation., Results: Thirty-nine patients were identified. At time of VAD implantation, 18 patients had ≥3 MRFs, 21 had 1 to 2 MRFs, and 0 had 0 MRFs. At time of transplant, 6 patients had ≥3 MRFs, 17 had 1 to 2 MRFs, and 16 had 0 MRFs. Hospital mortality occurred in 50% (3 out of 6) patients with ≥3 MRFs at transplant vs 0% of patients with 1 to 2 and 0 MRFs (P = .01 for ≥3 vs 1-2 and 0 MRFs). MRFs independently associated with hospital mortality included paralytics (1.76 [range, 1.32-2.30]), ventilator (1.59 [range, 1.28-1.97]), total parenteral nutrition dependence (1.49 [range, 1.07-2.07]), and renal dysfunction (1.31 [range, 1.02-1.67]). Two late mortalities occurred (3.6 and 5.7 y), both in patients with 1 to 2 MRFs at transplant. Overall posttransplant survival was significantly worse for ≥3 versus 0 MRFs (P = .006) but comparable between other cohorts (P > .1)., Conclusions: VADs are associated with MRF reduction in children, yet those with persistent MRFs at transplant experience a high burden of mortality. Transplanting VAD patients with ≥3 MRFs may not be prudent. Time should be given on VAD support to achieve aggressive pre-transplant optimization of MRFs., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: To assess rates of cardiac surgery and the clinical and demographic features that influence surgical vs nonsurgical treatment of congenital heart disease (CHD) in patients with trisomy 13 (T13) and trisomy 18 (T18) in the United States., Study Design: A retrospective study was performed using the Pediatric Health Information System. All hospital admissions of children (<18 years of age) with T13 and T18 in the United States were identified from 2003 through 2022. International Classifications of Disease (ICD) codes were used to identify presence of CHD, extracardiac comorbidities/malformations, and performance of cardiac surgery., Results: Seven thousand one hundred thirteen patients were identified. CHD was present in 62% (1625/2610) of patients with T13 and 73% (3288/4503) of patients with T18. The most common CHD morphologies were isolated atrial/ventricular septal defects (T13 40%, T18 42%) and aortic hypoplasia/coarctation (T13 21%, T18 23%). Single-ventricle morphologies comprised 6% (100/1625) of the T13 and 5% (167/3288) of the T18 CHD cohorts. Surgery was performed in 12% of patients with T13 plus CHD and 17% of patients with T18 plus CHD. For all cardiac diagnoses, <50% of patients received surgery. Nonsurgical patients were more likely to be born prematurely (P < .05 for T13 and T18). The number of extracardiac comorbidities was similar between surgical/nonsurgical patients with T13 (median 2 vs 2, P = .215) and greater in surgical vs nonsurgical patients with T18 (median 3 vs 2, P < .001). Hospital mortality was <10% for both surgical cohorts., Conclusions: Patients with T13 or T18 and CHD receive surgical palliation, but at a low prevalence (≤17%) nationally. Given operative mortality <10%, opportunity exists perhaps for quality improvement in the performance of cardiac surgery for these vulnerable patient populations., Competing Interests: Declaration of Competing Interest The authors report no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Total Cardiac Volume (TCV)-based size matching using Computed Tomography (CT) is a novel technique to compare donor and recipient heart size in pediatric heart transplant that may increase overall utilization of available grafts. TCV requires manual segmentation, which limits its widespread use due to time and specialized software and training needed for segmentation. This study aims to determine the accuracy of a Deep Learning (DL) approach using 3-dimensional Convolutional Neural Networks (3D-CNN) to calculate TCV, with the clinical aim of enabling fast and accurate TCV use at all transplant centers. Ground truth TCV was segmented on CT scans of subjects aged 0-30 years, identified retrospectively. Ground truth segmentation masks were used to train and test a custom 3D-CNN model consisting of a DenseNet architecture in combination with residual blocks of ResNet architecture. The model was trained on a cohort of 270 subjects and a validation cohort of 44 subjects (36 normal, 8 heart disease retained for model testing). The average Dice similarity coefficient of the validation cohort was 0.94 ± 0.03 (range 0.84-0.97). The mean absolute percent error of TCV estimation was 5.5%. There is no significant association between model accuracy and subject age, weight, or height. DL-TCV was on average more accurate for normal hearts than those listed for transplant (mean absolute percent error 4.5 ± 3.9 vs. 10.5 ± 8.5, p = 0.08). A deep learning-based 3D-CNN model can provide accurate automatic measurement of TCV from CT images. This initial study is limited as a single-center study, though future multicenter studies may enable generalizable and more accurate TCV measurement by inclusion of more diverse cardiac pathology and increasing the training data., (© 2024. The Author(s).)

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., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The study objective was to determine if intraoperative peritoneal catheter placement is associated with improved outcomes in neonates undergoing high-risk cardiac surgery with cardiopulmonary bypass., Methods: This propensity score-matched retrospective study used data from 22 academic pediatric cardiac intensive care units. Consecutive neonates undergoing Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 3 to 5 cardiac surgery with cardiopulmonary bypass at centers participating in the NEonatal and Pediatric Heart Renal Outcomes Network collaborative were studied to determine the association of the use of an intraoperative placed peritoneal catheter for dialysis or passive drainage with clinical outcomes, including the duration of mechanical ventilation., Results: Among 1490 eligible neonates in the NEonatal and Pediatric Heart Renal Outcomes Network dataset, a propensity-matched analysis was used to compare 395 patients with peritoneal catheter placement with 628 patients without peritoneal catheter placement. Time to extubation and most clinical outcomes were similar. Postoperative length of stay was 5 days longer in the peritoneal catheter placement cohort (17 vs 22 days, P  = .001). There was a 50% higher incidence of moderate to severe acute kidney injury in the no-peritoneal catheter cohort (12% vs 18%, P  = .02). Subgroup analyses between specific treatments and in highest risk patients yielded similar associations., Conclusions: This study does not demonstrate improved outcomes among neonates with placement of a peritoneal catheter during cardiac surgery. Outcomes were similar apart from longer hospital stay in the peritoneal catheter cohort. The no-peritoneal catheter cohort had a 50% higher incidence of moderate to severe acute kidney injury (12% vs 18%). This analysis does not support indiscriminate peritoneal catheter use, although it may support the utility for postoperative fluid removal among neonates at risk for acute kidney injury. A multicenter controlled trial may better elucidate peritoneal catheter effects., Competing Interests: The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (© 2024 The Author(s).)

Background: Recently, several centers in the United States have begun performing donation after circulatory death (DCD) heart transplants (HTs) in adults. We sought to characterize the recent use of DCD HT, waitlist time, and outcomes compared to donation after brain death (DBD)., Methods: Using the United Network for Organ Sharing database, 10,402 adult (aged >18 years) HT recipients from January 2019 to June 2022 were identified: 425 (4%) were DCD and 9,977 (96%) were DBD recipients. Posttransplant outcomes in matched and unmatched cohorts and waitlist times were compared between groups., Results: DCD and DBD recipients had similar age (57 years for both, p = 0.791). DCD recipients were more likely White (67% vs 60%, p = 0.002), on left ventricular assist device (LVAD; 40% vs 32%, p < 0.001), and listed as status 4 to 6 (60% vs 24%, p < 0.001); however, less likely to require inotropes (22% vs 40%, p < 0.001) and preoperative extracorporeal membrane oxygenation (0.9% vs 6%, p < 0.001). DCD donors were younger (29 vs 32 years, p < 0.001) and had less renal dysfunction (15% vs 39%, p < 0.001), diabetes (1.9% vs 3.8%, p = 0.050), or hypertension (9.9% vs 16%, p = 0.001). In matched and unmatched cohorts, early survival was similar (p = 0.22). Adjusted waitlist time was shorter in DCD group (21 vs 31 days, p < 0.001) compared to DBD cohort and 5-fold shorter (DCD: 22 days vs DBD: 115 days, p < 0.001) for candidates in status 4 to 6, which was 60% of DCD cohort., Conclusions: The community is using DCD mostly for those recipients who are expected to have extended waitlist times (e.g., durable LVADs, status >4). DCD recipients had similar posttransplant early survival and shorter adjusted waitlist time compared to DBD group. Given this early success, efforts should be made to expand the donor pool using DCD, especially for traditionally disadvantaged recipients on the waitlist., (Copyright © 2023 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: In pediatric heart transplantation, surgeons historically avoided donors requiring cardiopulmonary resuscitation (CPR), despite evidence that donor CPR does not change posttransplant survival (PTS). This study sought to determine whether CPR duration affects PTS., Methods: All potential brain-dead donors aged <40 years from 2001 to 2021 consented for heart procurement were identified in the United Network for Organ Sharing database (n = 54,671). Organ acceptance was compared by CPR administration and duration. All recipients aged <18 years with donor CPR data were then identified (n = 5680). Survival analyses were conducted using increasing CPR duration as a cut point to identify the shortest duration beyond which PTS worsened. Additional analyses were performed with multivariable and cubic spline regression., Results: Fifty-one percent of donors (28,012 of 54,671) received CPR. Donor acceptance was lower after CPR (54% vs 66%; P < .001) and across successive quartiles of CPR duration (P < .001). Of the transplant recipients, 48% (2753 of 5680) belonged to the no-CPR group, and 52% (2927 of 5680) belonged to the CPR group. Kaplan-Meier analyses of CPR duration attained significance at 55 minutes, after which PTS worsened (11.1 years vs 9.2 years; P = .025). There was no survival difference between the CPR ≤55 minutes group and the no-CPR group (11.1 years vs 11.2 years; P = .571). A cubic spline regression model confirmed that PTS worsened at more than 55 minutes of CPR. A Cox regression demonstrated that CPR >55 minutes predicted worsened PTS relative to no CPR (HR, 1.51; P = .007) but CPR ≤55 minutes did not (HR, 1.01; P = .864)., Conclusions: Donor CPR decreases organ acceptance for transplantation; however, shorter durations (≤55 minutes) had equivalent PTS when controlling for other risk factors., (Copyright © 2024 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: With rates of potential donor heart discard as high as 66% nationally, quality improvement efforts must seek to optimize donor utilization. Whether the timing of donor brain death declaration (BDD) influences organ acceptance is understudied. The authors sought to characterize the impacts of time between donor hospital admission and BDD on heart utilization and posttransplant outcomes., Methods: All potential heart donors and recipients in the United Network for Organ Sharing database were identified (2006-2021). Admission-to-BDD cohorts were: 1 to 2 d (n = 52 469), 3 to 4 d (n = 44 033), 5 to 7 d (n = 24 509), and 8 to 10 d (n = 8576). Donor clinical characteristics were compared between cohorts, and donor acceptance was assessed using multivariable binary logistic regression. Recipient posttransplant survival was assessed with the Kaplan-Meier method., Results: Donor demographics and comorbidity profiles (diabetes and hypertension) were comparable across cohorts. Anoxia/overdose deaths were more common (10% > 21% > 24% > 18%, respectively) and cardiopulmonary resuscitation requirements were higher (37% > 52% > 58% > 47%) when BDD occurred longer after admission. Renal dysfunction (44% > 44% > 35% > 29%) and inotrope requirements (52% > 25% > 36% > 29%) were lower in the later BDD cohorts. Proportions of hepatic dysfunction (18%-21%) and left ventricular ejection fraction <50% (13%-16%) were clinically equivalent. Donor acceptance differed by admission-to-BDD cohort (36% [1-2 d], 34% [3-4 d], 30% [5-7 d], and 28% [8-10 d]). Admission-to-BDD >4 d was independently associated with lower odds of acceptance on multivariable analysis (odds ratio 0.79, P  < 0.001). Recipients experienced equivalent posttransplant survival for all donor admission-to-BDD cohorts ( P  = 0.999 adults and P  = 0.260 pediatrics)., Conclusions: Heart donors with later BDD were disproportionately discarded despite similar-to-favorable overall clinical profiles, resulting in nearly 3000 fewer transplants during the study. Increased utilization of donors with later BDD and "high-risk" characteristics (eg, anoxia/overdose, cardiopulmonary resuscitation requirement) can improve rates of transplantation without compromising outcomes., Competing Interests: F.Z. is a transplant procurement surgeon for TransMedics Inc. The other authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Pulmonary vascular disease (PVD) represents an important clinical indication for lung transplant (LTx) in infants, children, and adolescents. There is limited information on LTx outcomes in these patients. We explored LTx volumes and post-LTx survival in children with PVD compared to other diagnoses. The UNOS Registry was queried from 1989 to 2020 to identify first-time pediatric LTx recipients (< 18 yo). PVD was categorized as idiopathic pulmonary arterial hypertension (IPAH) and non-idiopathic arterial hypertension (non-IPAH) and compared to all other patients as other diagnoses. Univariate and multivariate regression models were performed. 984 pediatric LTx patients (593 before 2010 and 391 during/after 2010) were identified, of which 145 (14.7%) had PVD. There has been no significant change in annual rate of all LTxs over comparative eras. However, there has been a decrease in rate of LTxs for PVD patients. Children with PVD had similar survival to other LTx groups in the early era (p = 0.2) and the latter era (p = 0.9). Univariate Cox models, showed that LTx in patients with PVD was associated with a significantly less risk of mortality for children aged 6-11 years compared to younger and older cohorts (HR = 0.4 [0.17-0.98]; p = 0.045), whereas multivariate analysis showed a trend toward higher mortality in 11-17-year-olds (HR = 1.54 [0.97-2.45]; p = 0.06). For PVD patients, oxygen supplementation and ventilator support at LTx were associated with worse post-transplant survival (p = 0.029 and p = 0.01). There has been a decrease in LTx volume for pediatric patients with PVD in the modern era. Post-LTx outcomes for children with PVD are similar to those of other diagnoses in both eras, with children aged 6-11 years having the best survival. Given these findings, LTx should be considered for this patient population., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Objective: To characterize national experience with surgical aortic valve repair in pediatric patients., Methods: Patients in the Pediatric Health Information System database aged 17 years or younger with International Statistical Classification of Diseases and Related Health Problems codes for open aortic valve repair from 2003 to 2022 were included (n = 5582). Outcomes of reintervention during index admission (repeat repair, n = 54; replacement, n = 48; and endovascular intervention, n = 1), readmission (n = 2176), and in-hospital mortality (n = 178) were compared. A logistic regression was performed for in-hospital mortality., Results: One-quarter (26%) of patients were infants. The majority (61%) were boys. Heart failure was present in 16% of patients, congenital heart disease in 73%, and rheumatic disease in 4%. Valve disease was insufficiency in 22% of patients, stenosis in 29%, and mixed in 15%. The highest quartile of centers by volume (median, 101 cases; interquartile range, 55-155 cases) performed half (n = 2768) of cases. Infants had the highest prevalence of reintervention (3%; P < .001), readmission (53%; P < .001), and in-hospital mortality (10%; P < .001). Previously hospitalized patients (median, 6 days; interquartile range, 4-13 days) were at higher risk for reintervention (4%; P < .001), readmission (55%; P < .001), and in-hospital mortality (11%; P < .001), as were patients with heart failure (reintervention [6%; P < .001], readmission [42%; P = .050], and in-hospital mortality [10%; P < .001]). Stenosis was associated with reduced reintervention (1%; P < .001) and readmission (35%; P = .002). The median number of readmissions was 1 (range, 0-6) and time to readmission was 28 days (interquartile range, 7-125 days). A regression of in-hospital mortality identified heart failure (odds ratio, 3.05; 95% CI, 1.59-5.49), inpatient status (odds ratio, 2.40; 95% CI, 1.19-4.82), and infancy (odds ratio, 5.70; 95% CI, 2.60-12.46) as significant., Conclusions: The Pediatric Health Information System cohort demonstrated success with aortic valve repair; however, early mortality remains high in infants, hospitalized patients, and patients with heart failure., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

The demand for organs for lung transplantation (LTx) continues to outweigh supply. However, nearly 75% of donor lungs are never transplanted. LTx offer acceptance practices and the effects on waitlist/post-transplant outcomes by candidate clinical acuity are understudied. UNOS was used to identify all LTx candidates, donors, and offers from 2005 to 2019. Candidates were grouped by Lung Allocation Score (LAS; applicable post-2005, ages ≥12 years): LAS<40, 40-60, 61-80, and >80. Offer acceptance patterns, waitlist death/decompensation, and post-transplant survival (PTS) were compared. "Acceptable organ offers" were those from donors whose organs were accepted for transplantation. Approximately 3 million offers to 34,531 candidates were reviewed. Median waitlist durations were: 9 days-(LAS>80), 17 days-(LAS 61-80), 42 days-(LAS 40-60), 125 days-(LAS<40) (P < 0.001 between all). Per waitlist-day, offer rates were: total offers - 0.8/day-(LAS>80), 0.7/day-(LAS 61-80), 0.6/day-(LAS 40-60), 0.4/day-(LAS<40); acceptable offers - 0.34/day-(LAS>80), 0.32/day-(LAS 61-80), 0.24/day-(LAS 40-60), 0.15/day-(LAS<40) (both P < 0.001 between all LAS). Among patients who experienced waitlist mortality/decompensation, ≥1 acceptable offer was declined in 92% (3939/4270) of patients - 78% for LAS >80, 88% for LAS 61-80, 93% for LAS 40-60, and 96% for LAS <40. Thirty-day waitlist mortality/decompensation rates were: 46%-(LAS>80), 24%-(LAS 61-80), 5%-(LAS 40-60), <1%-(LAS<40) (P < 0.001 between all). PTS was equivalent between patients for whom the first/second offer vs later offers were accepted (all LAS P > 0.4). The first offers that LTx candidates receive (including acceptable organs) are declined for nearly all candidates. Healthier candidates can afford offer selectivity but more ill patients (LAS>60) cannot, experiencing exceedingly high 30-day waitlist mortality., (Copyright © 2022 Elsevier Inc. All rights reserved.)

In the US, the first pediatric donation after circulatory death (DCD) thoracic transplant was done in 2004; however, ethical controversy led to minimal utilization of these donors. The present study was performed to characterize the current state of pediatric DCD heart and lung transplantation (HTx, LTx). Children (<18 year old) who underwent HTx or LTx using DCD donors from June 2004 to June 2022 were identified in the United Network for Organ Sharing registry. A total of 14 DCD recipients were identified: 7 (50%) HTx and 7 (50%) LTx. Donor and recipient demographics are described in Table 1. One and 5-year post-transplant survival were as follows: HTx recipients (64% for each) and LTx recipients (86%, 55%). Although often discussed, the national experience with DCD donors for pediatric HTx and LTx remains limited and not being practiced consistently by any pediatric program. Given the critical organ shortage, DCD use in the field of pediatric thoracic transplantation should be strongly considered., (Copyright © 2023 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Rationale: Organ size matching is an important determinant of successful allocation and outcomes in lung transplantation. While computed tomography (CT) is the gold standard, it is rarely used in an organ-donor context, and chest X-ray (CXR) may offer a practical and accurate solution in estimating lung volumes for donor and recipient size matching. We compared CXR lung measurements to CT-measured lung volumes and traditional estimates of lung volume in the same subjects., Methods: Our retrospective study analyzed clinically obtained CXR and CT lung images of 250 subjects without evidence of lung disease (mean age 9.9 ± 7.8 years; 129 M/121F). From CT, each lung was semi-automatically segmented and total lung volumes were quantified. From anterior-posterior CXR view, each lung was manually segmented and areas were measured. Lung lengths from the apices to the mid-basal regions of each lung were measured from CXR. Quantified CT lung volumes were compared to the corresponding CXR lung lengths, CXR lung areas, height, weight, and predicted total lung capacity (pTLC)., Results: There are strong and significant correlations between CT volumes and CXR lung areas in the right lung (R 2  = .89, p < .0001), left lung (R 2  = .87, p < .0001), and combined lungs (R 2  = .89, p < .0001). Similar correlations were seen between CT volumes and CXR measured lung lengths in the right lung (R 2  = .79, p < .0001) and left lung (R 2  = .81, p < .0001). This correlation between anatomical lung volume (CT) and CXR was stronger than lung-volume correlation to height (R 2  = .66, p < .0001), weight (R 2  = .43, p < .0001), or pTLC (R 2  = .66, p < .0001)., Conclusion: CXR measures correlate much more strongly with true lung volumes than height, weight, or pTLC. The ability to obtain efficient and more accurate lung volume via CXR has the potential to change our current listing practices of using height as a surrogate for lung size, with a case example provided., (© 2023 Wiley Periodicals LLC.)

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., (Copyright © 2023 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this study was to assess post-transplantation outcomes in recipients with increased pulmonary vascular resistance (PVR) in relation to donor size., Methods: The United Network for Organ Sharing database was used to identify patients ages 0 to 18 years at time of listing who underwent transplantation from 2010 to 2019 and for whom cardiac catheterization and donor-recipient weight ratio data were available. Patients were divided according to listing PVR into <3, 3 to 6, and >6 Wood units. Donor-recipient weight ratio was categorized as undersized (≤0.80), midsize (0.81-1.2), and oversized (>1.2). Subgroup analysis was done with an additional supersized group (>2.0)., Results: Fourteen hundred ninety-one patients met study criteria. Median age was 10 (interquartile range, 3-15) years and 45% were female. Four percent of heart transplantation cases used undersized, 45% used midsize, and 51% used oversized organs. More patients with PVR >6 were received an oversized organ transplant compared with patients with PVR <3; 59% (148/252) versus 48% (430/894); P = .003. There was no difference in survival among organ size groups regardless of PVR; this includes patients with PVR >6 at listing who received an oversized organ transplant versus an undersized (P = .359) or midsized (P = .956) organ. In subgroup analysis, even in patients who received a supersized organ transplant, there was no survival difference noted regardless of PVR., Conclusions: Despite a persistent practice pattern to transplant oversized organs in high-PVR patients, there remains no difference in post-transplantation survival among these patients and those who received smaller organ transplants. Therefore, transplants in patients with high PVR should not be delayed by waiting for larger donors., (Copyright © 2022 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Objective: Several human studies have associated nitric oxide administration via the cardiopulmonary bypass circuit with decreased incidence of cardiopulmonary bypass-associated acute kidney injury, but histopathologic and serologic evidence of nitric oxide efficacy for acute kidney injury attenuation are lacking., Methods: By using a survival ovine model (72 hours), acute kidney injury was induced by implementing low-flow cardiopulmonary bypass for 2 hours, followed by full-flow cardiopulmonary bypass for 2 hours. The nitric oxide cohort (n = 6) received exogenous nitric oxide through the cardiopulmonary bypass circuit via the oxygenator, and the control group (n = 5) received no nitric oxide. Serial serologic biomarkers and renal histopathology were obtained., Results: Baseline characteristics (age, weight) and intraoperative parameters (cardiopulmonary bypass time, urine output, heart rate, arterial pH, and lactate) were equivalent (P > .10) between groups. Postoperatively, urine output, heart rate, respiratory rate, and peripheral arterial saturation were equivalent (P > .10) between groups. Post-cardiopulmonary bypass creatinine elevations from baseline were significantly greater in the control group versus the nitric oxide group at 16, 24, and 48 hours (all P < .05). Histopathologic evidence of moderate/severe acute kidney injury (epithelial necrosis, tubular slough, cast formation, glomerular edema) occurred in 60% (3/5) of the control group versus 0% (0/6) of the nitric oxide group. Cortical tubular epithelial cilia lengthening (a sensitive sign of cellular injury) was significantly greater in the control group than in the nitric oxide group (P = .012)., Conclusions: In a survival ovine cardiopulmonary bypass model, nitric oxide administered with cardiopulmonary bypass demonstrated serologic and histologic evidence of renal protection from acute kidney injury. These results provide insight into 1 potential mechanism for cardiopulmonary bypass-associated acute kidney injury and supports continued study of nitric oxide via cardiopulmonary bypass circuit for prevention of acute kidney injury., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)