Guidelines vs Practice: Surgical Versus Transcatheter Aortic Valve Replacement in Adults ≤60 Years.

BACKGROUND: Consensus guidelines recommend surgical aortic valve replacement (SAVR) over transcatheter aortic valve replacement (TAVR) in patients with severe aortic stenosis aged ≤65 years. This analysis evaluates clinical practice and outcomes of TAVR and SAVR in patients aged ≤60 years. METHODS: We identified 2360 patients aged ≤60 years, including 523 TAVR (22.2%) and 1837 SAVR (77.8%) procedures, from 2013 through 2021 using the California Department of Health Care Access and Information database. The median follow-up time was 2.4 years (interquartile range, 1.1-4.5 years) after TAVR and 4.9 years (interquartile range, 2.8-6.9 years) after SAVR. The primary outcome was 5-year survival. Secondary outcomes included cumulative incidences of reoperation, endocarditis, stroke, and heart failure readmissions with death as a competing risk, compared using propensity score matching. RESULTS: Between 2013 and 2021 TAVR rates in patients aged ≤60 years increased from 7.2% to 45.7% (annual increase of 4.7%, P < .001). Mortality at 30 days was similar for SAVR and TAVR (0.2% vs 0.4%, P = .20). In 358 propensity-matched pairs, TAVR was associated with an increased hazard of 5-year mortality (hazard ratio, 2.5; 95% CI, 1.1-3.7; P = .02). There was no significant difference in the cumulative incidences of reoperation (2.2% vs 3.8%, P = .25), stroke (1.1% vs 0.8%, P = .39), endocarditis (0.8% vs 0.4%, P = .38), and heart failure readmission (1.9% vs 1.2%, P = .10). CONCLUSIONS: TAVR use approaches SAVR use in patients aged ≤60 years in California and is associated with significantly worse 5-year survival. This may indicate a need for randomized trials to inform best practice recommendations.

The Society of Thoracic Surgeons Preoperative Beta Blocker Working Group Interim Report.

BACKGROUND: Atrial fibrillation (AF) occurs commonly after cardiac surgery and is associated with multiple adverse outcomes. Older randomized trials suggested that perioperative ß- blockade reduced postoperative AF, and The Society of Thoracic Surgeons (STS) coronary artery bypass grafting (CABG) composite measure includes ß-blocker administration preoperatively within 24 hours of surgery and at discharge. However, some more recent studies suggest preoperative ß-blockade has limited value and question its continuation as an STS quality measure. METHODS: In 2022, an STS Preoperative Beta Blocker Working Group was formed with representatives from the STS and the Society of Cardiovascular Anesthesiologists. Published randomized trials, observational studies, societal guidelines, and the current state of available data from the STS Adult Cardiac Surgery Database (ACSD) were reviewed. RESULTS: Review of existing studies reveals substantial heterogeneity or insufficient detail regarding specific ß-blockers used, timing of initiation, management of patients on chronic ß-blockade, and whether other proarrhythmic or antiarrhythmic drugs were used concurrently. Further, ß-blocker data currently collected in the STS ACSD lack sufficient granularity. CONCLUSIONS: Because a new randomized trial seems unlikely, the Working Group believes that more granular data on real-world practice would facilitate assessment of the value of preoperative ß-blockade in the current era, development of best practice recommendations, and evaluation of their continued appropriateness as an STS quality metric. STS ACSD participants have been invited to participate in a voluntary survey whose additional data, when linked to STS ACSD records, will better delineate contemporary ß-blocker practice and outcomes.

Centralized Static Ex-Vivo Lung Perfusion in the United States.

BACKGROUND: Ex-vivo lung perfusion (EVLP) may improve donor lung utilization but requires significant infrastructure and expertise. Centralized EVLP facilities may mitigate these requirements. METHODS: From the United Network for Organ Sharing database, we identified 345 adults undergoing isolated, first-time lung transplantation using donor lungs perfused by static EVLP (03/01/2018-12/31/2022). Recipients of lungs perfused at centralized EVLP facilities (n=165) were compared to recipients of lungs perfused at individual transplant centers (n=180). Propensity score matching was used to create balanced groups for comparison. RESULTS: Centralized EVLP facilities were increasingly utilized from 2018 to 2022 (35.3 vs. 55.8%, p=0.04) and were more likely used when the annual center volume of EVLP lung transplants was low. Compared to allografts placed on EVLP at individual transplant centers, those placed on EVLP at centralized facilities had longer median ischemic time (11.3 vs. 9.6 hours, p<0.001) and were less likely to come from donation after circulatory death donors (25.4 vs. 39.5%, p=0.003) or be used for double lung transplant (73.3 vs. 83.9%, p=0.02). In 102 well-matched recipients, 2-year survival was equivalent between those receiving allografts perfused at centralized facilities (77.9% [95% CI 68.0-85.1%]) versus individual transplant centers (77.7% [95% CI 67.8-84.9%], p=0.90). Multivariable Cox regression analysis also showed equivalent 2-year survival (adjusted hazard ratio 1.02, 95% CI 0.57-1.84, p=0.95). CONCLUSIONS: Transplanting lung allografts that underwent static EVLP at centralized facilities had similar outcomes compared to transplanting lungs perfused at individual transplant centers. The centralized model of clinical EVLP can potentially improve access to EVLP.

Descending Thoracic and Thoracoabdominal Aortic Aneurysm Repairs: The Society of Thoracic Surgeons Adult Cardiac Surgery Database Analysis.

BACKGROUND: Contemporary national outcomes of open and endovascular aortic repair for descending thoracic aortic aneurysms (DTAAs) and thoracoabdominal aortic aneurysms (TAAAs) are unclear. This study evaluated this issue by using The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database (ACSD). METHODS: From July 1, 2017 to June 30, 2022, study investigators identified 3522 adults who underwent planned DTAA repair (open, 328; endovascular, 1895) or TAAA repair (open, 870; endovascular, 429), after excluding ascending aorta or aortic arch aneurysms (zone 0, 1, or 2), interventions with a proximal extent in zone 0 or zone 1, juxtarenal or infrarenal aortic interventions, hybrid procedures, aortic trauma, and aortic infection. RESULTS: Most DTAA interventions (85.2%) were endovascular repairs, whereas most TAAA interventions were open repairs (66.9%). For DTAA interventions, the operative mortality, permanent stroke rate, and rate of spinal cord injury were 4.2%, 3.8%, and 2.4% for endovascular repairs and 9.2%, 8.5%, and 4.6% for open repairs, respectively (all P < .05). For TAAA interventions, the operative mortality, permanent stroke rate, and rate of spinal cord injury were 6.5%, 2.1%, and 3.0% for endovascular repairs and 11.7%, 6.0%, and 12.2% for open repairs, respectively (all P < .05). Increasing annual open TAAA repair volume was associated with lower odds of experiencing the composite of operative mortality, permanent stroke, or spinal cord injury. CONCLUSIONS: On the basis of STS ACSD data, endovascular repair was the predominant approach for treating DTAA, whereas most patients undergoing TAAA interventions had an open surgical repair. Outcome differences between open and endovascular approaches may be related to patient selection. Increasing center experience with open TAAA repair is associated with improved outcomes.

Surgical pulmonary arterioplasty at bidirectional cavopulmonary anastomosis leads to favorable pulmonary hemodynamics at final stage palliation.

Objective: Pulmonary arterioplasty (PA plasty) at bidirectional cavopulmonary anastomosis (BDCA) is associated with increased morbidity, but outcomes to final stage palliation are unknown. We sought to determine the influence of PA plasty on pulmonary artery growth and hemodyamics at Fontan. Methods: We retrospectively reviewed clinical data and outcomes for BDCA patients from 2006 to 2018. PA plasty was categorized by extent (type 1-4), as previously described. Outcomes included pulmonary artery reintervention and mortality before final palliation. Results: Five hundred eighty-eight patients underwent BDCA. One hundred seventy-nine patients (30.0%) underwent concomitant PA plasty. Five hundred seventy (97%) patients (169 [94%] PA plasty) survived to BDCA discharge. One hundred forty out of 570 survivors (25%) required PA/Glenn reintervention before final stage palliation (59 out of 169 [35%]) PA plasty; 81 out of 401 (20%) non-PA plasty; P < .001). Twelve-, 24-, and 36-month freedom from reintervention after BDCA was 80% (95% CI, 74-86%), 75% (95% CI, 69-82%), and 64% (95% CI, 57-73%) for PA plasty, and 95% (95% CI, 93-97%), 91% (95% CI, 88-94%), and 81% (95% CI, 76-85%) for non-PA plasty (P < .001). Prefinal stage mortality was 37 (6.3%) (14 out of 169 PA plasty; 23 out of 401 non-PA plasty; P = .4). Five hundred four (144 PA plasty and 360 non-PA plasty) patients reached final stage palliation (471 Fontan, 26 1.5-ventricle, and 7 2-ventricular repair). Pre-Fontan PA pressure and pulmonary vascular resistance were 10 mm Hg (range, 9-12 mm Hg) and 1.6 mm Hg (range, 1.3-1.9 mm Hg) in PA plasty and 10 mm Hg (range, 8-12 mm Hg) and 1.5 mm Hg (range, 1.3-1.9 mm Hg) in non-PA plasty patients, respectively (P = .29, .6). Fontan hospital mortality, length of stay, and morbidity were similar. Conclusions: PA plasty at BDCA does not confer additional mortality risk leading to final palliation. Despite increased pulmonary artery reintervention, there was reliable pulmonary artery growth and favorable pulmonary hemodynamics at final stage palliation.

Cardiac Surgery After Transcatheter Aortic Valve Replacement: Trends and Outcomes.

BACKGROUND: Reports of cardiac operations after transcatheter aortic valve replacement (TAVR) and early TAVR explantation are increasing. The purpose of this report is to document trends and outcomes of cardiac surgery after initial TAVR. METHODS: The Society of Thoracic Surgeons Adult Cardiac Surgery Database was queried for all adult patients undergoing cardiac surgery after a previously placed TAVR between January 2012 and March 2023. This identified an overall cohort and 2 subcohorts: nonaortic valve operations and surgical aortic valve replacement (SAVR) after previous TAVR. Cohorts were examined with descriptive statistics, trend analyses, and 30-day outcomes. RESULTS: Of 5457 patients who were identified, 2485 (45.5%) underwent non-SAVR cardiac surgery, and 2972 (54.5%) underwent SAVR. The frequency of cardiac surgery after TAVR increased 4235.3% overall and 144.6% per year throughout the study period. The incidence of operative mortality and stroke were 15.5% and 4.5%, respectively. Existing The Society of Thoracic Surgeons risk models performed poorly, because observed-to-expected mortality ratios were significantly >1.0. Among those undergoing SAVR after TAVR, increasing preoperative surgical urgency, age, dialysis, need for SAVR, and concomitant procedures were associated with increased mortality, whereas type of TAVR explant was not. CONCLUSIONS: The need for cardiac surgery, including redo SAVR after TAVR, is increasing rapidly. Risks are higher, and outcomes are worse than predicted. These data should closely inform heart team decisions if TAVR is considered at lowering age and risk profiles in the absence of longitudinal evidence.

Surgery and transcatheter intervention for degenerative mitral regurgitation in the United States.

OBJECTIVES: We evaluated practice trends and 3-year outcomes of transcatheter edge-to-edge repair (TEER) and surgical repair for degenerative mitral regurgitation in the United States. METHODS: From the Centers for Medicare and Medicaid Services data (2012-2019), 53,117 mitral valve interventions (surgery or TEER) were performed for degenerative mitral regurgitation, identified by excluding rheumatic and congenital disease, endocarditis, myocardial infarction, cardiomyopathy, and concomitant or prior coronary revascularizations. Median follow-up was 2.9 years (interquartile range, 1.2-5.1 years). End points were 3-year survival, stroke, mitral reinterventions, and heart failure readmissions. RESULTS: Volume of total annual mitral interventions did not significantly change (P = .18) between 2012 and 2019. However, surgical cases decreased by one-third, whereas TEER increased. Among 27,170 patients (52.5% men; mean age, 73.5 years) who underwent TEER (n = 7755) or surgical repair (n = 19,415), surgical patients were younger (71.8 vs 80.8 years; P < .001), with less comorbidity and frailty. In 4532 patient pairs matched for age, frailty, and comorbidity, 3-year survival after TEER was 65.9% (95% CI, 64.3%-67.6%) and 85.7% (95% CI, 84.5%-86.9%) after surgery (P < .001). Three years after TEER or surgery, stroke rates were 1.8% (95% CI, 1.5%-2.2%) and 2.0% (95% CI, 1.6%-2.4%) (P = .49); heart failure readmission rates were 17.8% (95% CI, 16.7%-18.9%) and 11.2% (95% CI, 10.3%-12.2%) (P < .001); and mitral reintervention rates were 6.1% (95% CI, 5.5%-6.9%) and 1.3% (95% CI, 1.0%-1.7%) (P < .001), respectively. CONCLUSIONS: Among Medicare beneficiaries with degenerative mitral regurgitation, an increase in TEER utilization was associated with worse survival, increased heart failure readmissions, and more mitral reinterventions. Randomized trials are needed to better inform treatment choice.

Heart transplantation in patients from socioeconomically distressed communities.

BACKGROUND: Studies examining heart transplantation disparities have focused on individual factors such as race or insurance status. We characterized the impact of a composite community socioeconomic disadvantage index on heart transplantation outcomes. METHODS: From the Scientific Registry of Transplant Recipients (SRTR), we identified 49,340 primary, isolated adult heart transplant candidates and 32,494 recipients (2005-2020). Zip code-level socioeconomic disadvantage was characterized using the Distressed Community Index (DCI: 0-most prosperous, 100-most distressed) based on education, poverty, unemployment, housing vacancies, median income, and business growth. Patients from distressed communities (DCI ≥ 80) were compared to all others. RESULTS: Patients from distressed communities were more often non-white, less educated, and had public insurance (all p < 0.01). Distressed patients were more likely to require ventricular assist devices at listing (29.4 vs 27.1%) and before transplant (44.8 vs 42.0%, both p < 0.001), and they underwent transplants at lower-volume centers (23 vs 26 cases/year, p < 0.01). Distressed patients had higher 1-year waitlist mortality or deterioration (12.3% [95% confidence interval (CI) 11.6-13.0] vs 10.9% [95% CI 10.5-11.3]) and inferior 5-year survival (75.3% [95% CI 74.0-76.5] vs 79.5% [95% CI 79.0-80.0]) (both p < 0.001). After adjustment, living in a distressed community was independently associated with an increased risk of waitlist mortality or deterioration hazard ratio (HR 1.10, 95% CI 1.02-1.18) and post-transplant mortality (HR 1.13, 95% CI 1.06-1.20). CONCLUSIONS: Patients from socioeconomically distressed communities have worse waitlist and post-transplant mortality. These findings should not be used to limit access to heart transplantation, but rather highlight the need for further studies to elucidate mechanisms underlying the impact of community-level socioeconomic disparity.

The Society of Thoracic Surgeons Adult Cardiac Surgery Database: 2023 Update on Procedure Data and Research.

The Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database is one of the largest and most comprehensive contemporary clinical databases in use. It now contains >9 million procedures from 1010 participants and 3651 active surgeons. Using audited data collection, it has provided the foundation for multiple risk models, performance metrics, health policy decisions, and a trove of research studies to improve the care of patients in need of cardiac surgical procedures. This annual report provides an update on the current status of the database and summarizes the development of new risk models and the STS Online Risk Calculator. Further, it provides insights into current practice patterns, such as the change in the demographics among patients undergoing aortic valve replacement, the use of minimally invasive techniques for valve and bypass surgery, or the adoption of surgical ablation and left atrial appendage ligation among patients with atrial fibrillation. Lastly, an overview of the research conducted using the STS Adult Cardiac Surgery Database and future directions for the database are provided.

Prospective Study of Risk Factors for Postoperative Atrial Fibrillation After Cardiac Surgery.

INTRODUCTION: To examine risk factors for new-onset postoperative atrial fibrillation (POAF) after cardiac surgery. METHODS: Patients enrolled in the Cardiothoracic Surgical Trials Network multicenter, randomized trial of rate control versus rhythm control for POAF were included. Predictors of POAF were determined using multivariable logistic regression. RESULTS: Among the 2104 patients who were enrolled preoperatively, 695 developed POAF (33.0%). Rates of POAF were 28.1% after isolated coronary artery bypass grafting (CABG), 33.7% after isolated valve repair or replacement, and 47.3% after CABG plus valve repair or replacement. Baseline characteristics associated with an increased risk of POAF identified on multivariable analysis included older age (odds ratio [OR] 1.57; 95% confidence interval [CI] 1.42-1.73, per 10 y), White race or non-Hispanic ethnicity (OR 1.52; CI: 1.11-2.07), history of heart failure (OR 1.55; CI: 1.16-2.08), and history of hypothyroidism (OR 1.42; CI 1.04-1.94). The type of cardiac procedure was associated with an increased risk of POAF with both isolated valve repair or replacement (OR 1.33, CI 1.08-1.64) and combined CABG plus valve repair or replacement (OR 1.64, CI 1.24-2.17) having increased risk of POAF compared to isolated CABG. No preoperative cardiac medication was associated with POAF. CONCLUSIONS: In this prospective cohort of patients, older age, a history of hypothyroidism, a history of heart failure, and valve repair or replacement, with or without CABG, and White non-Hispanic race were associated with an increased risk of POAF.

Limited cumulative experience with ex vivo lung perfusion is associated with inferior outcomes after lung transplantation.

OBJECTIVE: Ex vivo lung perfusion (EVLP) allows for prolonged preservation and evaluation/resuscitation of donor lungs. We evaluated the influence of center experience with EVLP on lung transplant outcomes. METHODS: We identified 9708 isolated, first-time adult lung transplants from the United Network for Organ Sharing database (March 1, 2018-March 1, 2022), 553 (5.7%) involved using donor lungs after EVLP. Using the total volume of EVLP lung transplants per center during the study period, centers were dichotomized into low- (1-15 cases) and high-volume (>15 cases) EVLP centers. RESULTS: Forty-one centers performed EVLP lung transplants, including 26 low-volume and 15 high-volume centers (median volume, 3 vs 23 cases; P < .001). Recipients at low-volume centers (n = 109) had similar baseline comorbidities compared with high-volume centers (n = 444). Low-volume centers used numerically more donation after circulatory death donors (37.6 vs 28.4%; P = .06) and more donors with Pao2/Fio2 ratio <300 (24.8 vs 9.7%; P < .001). After EVLP lung transplants, low-volume centers had worse 1-year survival (77.8% vs 87.5%; P = .007), with an adjusted hazard ratio of 1.63 (95% CI, 1.06-2.50, adjusting for recipient age, sex, diagnosis, lung allocation score, donation after circulatory death donor, donor Pao2/Fio2 ratio, and total annual lung transplant volume per center). When compared to non-EVLP lung transplants, 1-year survival of EVLP lung transplants was significantly worse at low-volume centers (adjusted hazard ratio, 2.09; 95% CI, 1.47-2.97) but similar at high-volume centers (adjusted hazard ratio, 1.14; 95% CI, 0.82-1.58). CONCLUSIONS: The use of EVLP in lung transplantation remains limited. Increasing cumulative EVLP experience is associated with improved outcomes of lung transplantation using EVLP-perfused allografts.

Coronary Artery Aneurysms, Arteriovenous Malformations, and Spontaneous Dissections-A Review of the Evidence.

BACKGROUND: Coronary artery aneurysms (CAAs), coronary arteriovenous malformations (CAVMs), and spontaneous coronary artery dissections (SCADs) are rare clinical entities, and much is unknown about their natural history, prognosis, and management. METHODS: A systematic search of MEDLINE, Embase, and Cochrane Library databases was performed in March 2023 to identify published papers related to CAAs, CAVMs, and SCADs. RESULTS: CAAs are found in 0.3% to 12% of patients undergoing angiography and are often associated with coronary atherosclerosis. They are usually asymptomatic but can be complicated by thrombosis in up to 4.8% of patients and rarely by rupture (0.2%). CAAs can be managed medically, percutaneously with stents or coil embolization, and surgically. The most common surgical procedure is ligation of the aneurysm, followed by coronary artery bypass grafting. The incidence of CAVMs is 0.1% to 0.2% in patients undergoing angiography, and they are most likely associated with congenital abnormal development of the coronary vessels. The diagnosis of CAVMs is usually incidental. Surgical or percutaneous intervention is indicated for patients with large CAVMs, which carry a potential risk of myocardial infarction. SCADs represent 1% to 4% of all acute coronary syndromes and typically affect young women. SCADs are strongly correlated with pregnancy, suggesting the role of sex hormones in their pathogenesis. Conservative management of SCAD is preferred for stable patients without signs of ischemia as spontaneous resolution is frequently reported. Unstable patients should undergo revascularization either percutaneously or with coronary artery bypass grafting. CONCLUSIONS: Further evidence regarding the management of these rare diseases is needed and can ideally be derived from multicenter collaborations.

Bicuspid aortic stenosis: National three-year outcomes of transcatheter versus surgical aortic valve replacement among Medicare beneficiaries.

OBJECTIVE: Randomized trials of transcatheter versus surgical aortic valve replacements have excluded bicuspid anatomy. We compared 3-year outcomes of transcatheter aortic valve replacement versus surgical aortic valve replacement in patients aged more than 65 years with bicuspid aortic stenosis. METHODS: The Centers for Medicare and Medicaid data were used to identify 6450 patients undergoing isolated surgical aortic valve replacement (n = 3771) or transcatheter aortic valve replacement (n = 2679) for bicuspid aortic stenosis (2012-2019). Propensity score matching with 21 baseline characteristics including frailty created 797 pairs. RESULTS: Unmatched patients undergoing transcatheter aortic valve replacement were older than patients undergoing surgical aortic valve replacement (78 vs 70 years), with more comorbidities and frailty (all P < .001). After matching, transcatheter aortic valve replacement was associated with a similar mortality risk compared with surgical aortic valve replacement within the first 6 months (hazard ratio [HR], 1.08, 95% CI, 0.67-1.69) but a higher mortality risk between 6 months and 3 years (HR, 2.16, 95% CI, 1.22-3.83). Additionally, transcatheter aortic valve replacement was associated with a lower risk of heart failure readmissions before 6 months (HR, 0.51, 95% CI, 0.31-0.87) but a higher risk between 6 months and 3 years (HR, 4.78, 95% CI, 2.21-10.36). The 3-year risks of aortic valve reintervention (HR, 1.03, 95% CI, 0.30-3.56) and stroke (HR, 1.21, 95% CI, 0.75-1.96) were similar. CONCLUSIONS: Among matched Medicare beneficiaries undergoing transcatheter aortic valve replacement or surgical aortic valve replacement for bicuspid aortic stenosis, 3-year mortality was higher after transcatheter aortic valve replacement. However, transcatheter aortic valve replacement was associated with a similar risk of mortality and a lower risk of heart failure readmissions during the first 6 months after the intervention. Randomized comparative data are needed to best inform treatment choice.

Impact of donor-recipient age-difference in adolescent heart transplantation.

INTRODUCTION: The relationship between donor age and adolescent heart transplant outcomes remains incompletely understood. We aimed to explore the effect of donor-recipient age difference on survival after adolescent heart transplantation. METHODS: The United Network for Organ Sharing database was used to identify 2,855 adolescents aged 10-17 years undergoing isolated primary heart transplantation from 1/1/2000 to 12/31/2022. The primary outcome was 10-year post-transplant survival. Multivariable Cox regression identified predictors of mortality after adjusting for donor and recipient characteristics. A restricted cubic spline assessed the non-linear association between donor-recipient age-difference and the adjusted relative mortality hazard. RESULTS: The median donor-recipient age-difference was +3 (range -13 to +47) years, and 17.7% (n = 504) of recipients had an age- difference > 10 years. Recipients with an age-difference > 10 years had a less favorable pre-transplant profile, including a higher incidence of priority status 1A (81.6%, n = 411 vs. 73.6%, n = 1730; p = .01). The 10-year survival rate was 54.6% (95% confidence interval (CI) 48.8- 60.4) among recipients with a donor-recipient age-difference > 10 years and 66.9% (95% CI: 64.4-69.4) among those with an age-difference ≤10 years. An age-difference > 10 years was an independent predictor of mortality (hazard ratio 1.43, 95% CI: 1.18-1.72, p < .001). Spline analysis demonstrated that the adjusted mortality hazard increased with increasingly positive donor-recipient age-difference and became significantly higher at an age-difference of 11 years. CONCLUSION: A donor-recipient age-difference > 11 years is independently associated with higher long-term mortality after adolescent heart transplantation. This finding may help inform acceptable donor selection practice for adolescent heart transplant candidates.

Repeat pediatric heart transplantation: A united network for organ sharing database analysis.

BACKGROUND: A history of congenital heart disease and previous transplantation are each independently associated with worse survival following pediatric heart transplantation. This study aimed to evaluate the characteristics and outcomes of children undergoing repeat heart transplantation in the United States based on the underlying diagnosis. METHODS: The United Network for Organ Sharing database was used to identify 8111 patients aged <18 years undergoing isolated heart transplantation from 2000 to 2021, including 435 (5.4%) repeat transplants. Restricted cubic spline analysis assessed the non-linear relationship between inter-transplant interval and the primary outcome of all-cause mortality or re-transplantation. Multivariable Cox regression assessed the impact of re-transplantation on the primary outcome. Median follow-up was 5.0 (interquartile range 1.9-9.9) years. RESULTS: Repeat transplant patients were older (median age 12 vs. 4 years; p < .001), and less likely to be in UNOS status 1A (66.0%, n = 287 vs. 81.0% n = 6217; p < .001) than primary transplant patients. Freedom from the primary outcome was 51.4% (95% confidence interval [CI] 45.5-57.2) among repeat transplants and 70.5% (95% CI 69.2-71.8) among primary transplants at 10 years (p < .001). Among repeat transplant patients, the relative hazard of the primary outcome became non-significant when the inter-transplant interval >3.6 years. Congenital heart disease was an independent predictor of mortality among primary (HR 1.8, 95% CI 1.6-1.9) but not repeat transplant (HR 1.1, 95% CI .8-1.6) patients. CONCLUSIONS: Long-term outcomes remain poor for patients undergoing repeat heart transplantation, particularly those with an inter-transplant interval <3.6 years. Underlying diagnosis does not impact outcomes after repeat transplantation, after accounting for other risk factors.