Heart Failure Staging and Indications for Advanced Therapies in Adults with Congenital Heart Disease.

Heart failure (HF) is common in adults with congenital heart disease (CHD), and it is the leading cause of death in this population. Adults with CHD presenting with stage D HF have a poor prognosis, and early recognition of signs of advanced HF and referral for advanced therapies for HF offer the best survival as compared with other therapies. The indications for advanced therapies for HF outlined in this article should serve as a guide for clinicians to determine the optimal time for referral. Palliative care should be part of the multidisciplinary care model for HF in patients with CHD.

Coarctation of Aorta With Tricuspid Aortic Valve Is Not Associated With Ascending Aortic Aneurysm.

BACKGROUND: Aortic aneurysm is common in patients with coarctation of aorta (COA), but it is unclear whether the risk of aortic aneurysms is due to COA or related to the presence of other risk factors such as bicuspid aortic valve (BAV) and hypertension. OBJECTIVES: The purpose of this study was to assess the relationship among COA, BAV, and thoracic aortic aneurysms. METHODS: A total of 867 patients with COA (COA group) were matched 1:1:1 to 867 patients with isolated BAV (BAV group) and 867 patients without structural heart disease (SHD) (no-SHD group). The COA group was further subdivided into a COA+BAV subgroup (n = 304 [35%]), and COA with tricuspid aortic valve (TAV) (COA+TAV subgroup [n = 563 (65%)]). Aortic dimensions were assessed at baseline and at 3, 5, and 7 years. RESULTS: Compared with the no-SHD group, the COA+BAV subgroup had larger aortic root diameter (37 mm [Q1-Q3: 30-43 mm] vs 32 mm [Q1-Q3: 27-35 mm]; P < 0.001) and mid ascending aorta dimeter (34 mm [Q1-Q3: 29-40 mm] vs 28 mm [Q1-Q3: 24-31 mm]; P = 0.008). Similarly, the BAV group had larger aortic root diameter (37 mm [Q1-Q3: 30-42 mm] vs 32 mm [Q1-Q3: 27-35 mm]; P < 0.001), and mid ascending aorta dimeter (35 mm [Q1-Q3: 30-40 mm] vs 28 mm [Q1-Q3: 24-31 mm]; P < 0.001). Compared with the COA+TAV subgroup, the COA+BAV subgroup and BAV group were associated with larger aortic root and mid ascending aorta diameter at baseline and follow-up. The risk of acute aortic complications was low in all groups. CONCLUSIONS: These findings suggest that BAV (and not COA) was associated with ascending thoracic aorta dimensions, and that patients with COA+TAV were not at a greater risk of developing ascending aortic aneurysms as compared with patients without SHD.

Right Heart Reverse Remodeling and Prosthetic Valve Function After Transcatheter vs Surgical Pulmonary Valve Replacement.

BACKGROUND: There are limited data about postprocedural right heart reverse remodeling and long-term prosthesis durability after transcatheter pulmonary valve replacement (TPVR) and how these compare to surgical pulmonary valve replacement (SPVR). OBJECTIVES: This study sought to compare right heart reverse remodeling, pulmonary valve gradients, and prosthetic valve dysfunction after TPVR vs SPVR. METHODS: Patients with TPVR were matched 1:2 to patients with SPVR based on age, sex, body surface area, congenital heart lesion, and procedure year. Right heart indexes (right atrial [RA] reservoir strain, RA volume index, RA pressure, right ventricular [RV] global longitudinal strain, RV end-diastolic area, and RV systolic pressure) were assessed at baseline (preintervention), 1 year postintervention, and 3 years postintervention. Pulmonary valve gradients were assessed at 1, 3, 5, 7, and 9 years postintervention. RESULTS: There were 64 and 128 patients in the TPVR and SPVR groups, respectively. Among patients with TPVR, 46 (72%) and 18 (28%) received Melody (Medtronic) vs SAPIEN (Edwards Lifesciences) valves, respectively. The TPVR group had greater postprocedural improvement in RA reservoir strain and RV global longitudinal strain at 1 and 3 years. The TPVR group had a higher risk of prosthetic valve dysfunction mostly because of a higher incidence of prosthetic valve endocarditis compared to SPVR but a similar risk of pulmonary valve reintervention because some of the patients with endocarditis received medical therapy only. Both groups had similar pulmonary valve mean gradients at 9 years postintervention. CONCLUSIONS: These data suggest a more favorable right heart outcome after TPVR. However, the risk of prosthetic valve endocarditis and prosthetic valve dysfunction remains a major concern.

Hemodynamics in Adults with Systemic Right Ventricles: Differences Between Congenitally Corrected and Complete Transposition of the Great Arteries.

Despite their anatomical differences, congenitally corrected (ccTGA) and complete transposition of the great arteries (d-TGA) post-atrial switch are frequently studied together and managed similarly from a medical standpoint due to the shared systemic right ventricle (sRV). The aim was to assess differences in their underlying hemodynamics. The study is a retrospective review of 138 adults with ccTGA or d-TGA post-atrial switch undergoing cardiac catheterization at Mayo Clinic, MN between 2000 and 2021. ccTGA was categorized into isolated or complex ccTGA depending on concomitant ventricular septal defect and/or left ventricular outflow obstruction. There were 53 patients with d-TGA (91% post-Mustard procedure), 51 with complex and 34 with isolated ccTGA. Isolated ccTGA patients were older (51.8 ± 13.1 years) than those with d-TGA (37.5 ± 8.3 years) or complex ccTGA (40.8 ± 13.4 years). There were no differences in sRV or left ventricular size and function across groups. The ccTGA group more commonly had ≥ moderate tricuspid regurgitation than those with d-TGA; ≥ moderate mitral and ≥ moderate pulmonary regurgitation were most prevalent in complex ccTGA. There were no differences in sRV end-diastolic pressure (sRVEDP) or PAWP between groups. However, the ratio of PAWP:sRVEDP was higher in those with d-TGA compared to those with ccTGA. Cardiac index was higher in the d-TGA group than both groups of ccTGA patients with the latter showing higher indices of ventricular afterload. In conclusion, despite sharing a sRV, adults with d-TGA and ccTGA have substantial differences in hemodynamics and structural/valvular abnormalities. Further investigation regarding disease-specific responses to heart failure therapy in those with d-TGA and ccTGA is warranted.

Diagnostic and Prognostic Role of Left Ventricular Strain Imaging in Adults with Coarctation of aorta.

The relative diagnostic and prognostic performance of left ventricular (LV) global longitudinal strain (LVGLS) compared with LV ejection fraction (LVEF) and the role of LVGLS for detecting the early stages of LV systolic dysfunction in adults with repaired coarctation of the aorta are unknown. This study aimed to address these knowledge gaps. We used a retrospective cohort study of adults with repaired coarctation of the aorta who underwent transthoracic echocardiogram (2003 to 2020). LV systolic function was assessed using LVEF (derived from volumetric analysis) and LVGLS (derived from speckle-tracking echocardiography). Of the 795 patients (age 36 ± 14 years), the mean LVEF and LVGLS were 62 ± 11% and 21 ± 4%, respectively. The prevalence of LV systolic dysfunction was higher when assessed using LVGLS than using LVEF (20% vs 6%, p <0.001). Of 795 patients, 94 (12%) patients died, of which 75 (9%) died from cardiovascular causes. LVGLS provided more robust prognostic power in predicting the all-cause mortality than LVEF, as evidenced by a higher C-statistic (0.743, 95% confidence interval 0.730 to 0.755 vs 0.782, 95% confidence interval 0.771 to 0.792, p <0.001). Furthermore, patients with normal LVEF in the setting of reduced LVGLS had a higher risk of all-cause mortality (than patients with normal LVGLS and LVEF) and were at risk for a temporal decrease in LVEF during follow-up. These findings suggest that the use of LVGLS for risk stratification can help identify high-risk patients and provide opportunities for interventions, which would, in turn, improve clinical outcomes. Further studies are required to empirically test these postulates.

Cardiac Reverse Remodeling and Changes in Heart Failure Indices After Transcatheter Tricuspid Valve Replacement in Adults With Congenital Heart Disease.

BACKGROUND: There are limited data about changes in cardiac function (cardiac reverse remodeling) and heart failure indices after transcatheter tricuspid valve-in-valve replacement (TT-VIVR). The purpose of this study was to evaluate cardiac reverse remodeling and temporal changes in heart failure indices after TT-VIVR in adults with congenital heart disease. METHODS: Retrospective cohort study of adults with congenital heart disease that underwent TT-VIVR and had >6 months of follow-up (January 1, 2011, to April 30, 2023). Echocardiographic indices of cardiac remodeling and heart failure indices (New York Heart Association class, NT-proBNP (N-terminal pro-brain natriuretic peptide), glomerular filtration rate, and model for end-stage liver disease excluding international normalized ratio score) were assessed preintervention and at 1-, 3-, and 5-year postintervention. RESULTS: Of 39 patients (age 39 [32-46] years), 14 (36%) and 25 (64%) received Melody valve and Sapien valve prosthesis, respectively. At 1-year post-TT-VIVR, there was a temporal improvement in right atrial reservoir strain (17±8% versus 22±8%, P<0.001), right atrial volume (81 [59-108] versus 63 [48-82] mL/m2, P<0.001), right atrial pressure (12±4% versus 6±4%, P<0.001), and right ventricular global longitudinal strain (-15±7% versus -20±7%, P<0.001). Similarly, there was a temporal improvement in NT-proBNP, glomerular filtration rate, model for end-stage liver disease excluding international normalized ratio score, and New York Heart Association class. The temporal improvements in heart failure indices and valve function were maintained at 3- and 5-year post-TT-VIVR. CONCLUSIONS: Considering the significant mortality risk associated with reoperations for tricuspid valve replacement, these data suggest favorable outcomes after TT-VIVR, and support TT-VIVR as a viable alternative to surgical tricuspid valve replacement, especially in high-risk patients.

Trends in cardiac implantable electronic device utilization in adults with congenital heart disease: a US nationwide analysis.

BACKGROUND: Adults with congenital heart disease (ACHD) have increased risk of arrhythmias warranting implantation of cardiac implantable electronic devices (CIEDs), which may parallel the observed increase in survival of ACHD patients over the past few decades. We sought to characterize the trends and outcomes of CIED implantation in the inpatient ACHD population across US from 2005 to 2019. METHODS: A retrospective analysis of the Nationwide Inpatient Sample (NIS) identified 1,599,519 unique inpatient ACHD admissions (stratified as simple (85.1%), moderate (11.5%), and complex (3.4%)) using the International Classification of Diseases 9/10-CM codes. Hospitalizations for CIED implantation (pacemaker, ICD, CRT-p/CRT-d) were identified and the trends analyzed using regression analysis (2-tailed p < 0.05 was considered significant). RESULTS: A significant decrease in the hospitalizations for CIED implantation across the study period [3.3 (2.9-3.8)% in 2005 vs 2.4 (2.1-2.6)% in 2019, p < 0.001] was observed across all types of devices and CHD severities. Pacemaker implantation increased with each age decade, whereas ICD implantation rates decreased over 70 years of age. Complex ACHD patients receiving CIED were younger with a lower prevalence of age-related comorbidities, however, had a greater prevalence of atrial/ventricular tachyarrhythmias and complete heart block. The observed inpatient mortality rate was 1.2%. CONCLUSIONS: In a nationwide analysis, we report a significant decline in CIED implantation between 2005 and 2019 in ACHD patients. This may either be due to a greater proportion of hospitalizations resulting from other complications of ACHD or reflect a declining need for CIED due to advances in medical/surgical therapies. Future prospective studies are needed to elucidate this trend further.

Determinants and prognostic implications of left atrial reverse remodelling after coarctation of aorta repair in adults.

AIMS: Left atrial (LA) dysfunction and atrial fibrillation are also relatively common in adults with coarctation of aorta (COA), and the severity of LA dysfunction is associated with a higher risk of atrial fibrillation in this population. The purpose of this study was to determine whether LA function improved after COA repair (LA reverse remodelling), and the relationship between LA reverse remodelling and atrial fibrillation. METHODS AND RESULTS: Retrospective cohort study of adults undergoing COA repair (2003-20). LA reservoir strain was assessed pre intervention and 12-24 months post intervention, using speckle tracking echocardiography. Incident atrial fibrillation was assessed from COA repair to last follow-up. Of 261 adults who underwent COA repair [age 37 ± 13 years; males 148 (57%)], 124 (47%) and 137 (53%) presented with native vs. recurrent COA, respectively. Of 261 patients, 231 (82%) and 48 (18%) underwent surgical and transcatheter COA repair, respectively. The LA reservoir strain increased from 32 ± 8% (pre intervention) to 39 ± 7% (post intervention), yielding a relative increase of 21 ± 5%. Older age [ß ± standard error (SE) -0.16 ± 0.09 per 5 years, P = 0.02], higher systolic blood pressure (ß ± SE -0.12 ± 0.04 per 5 mmHg, P = 0.005), and higher residual COA mean gradient (ß ± SE -0.17 ± 0.06 per 5 mmHg, P = 0.002) post intervention were associated with less LA reverse remodelling, after adjustment for sex, hypertension diagnosis, and left ventricular indices. LA reverse remodelling (hazard ratio 0.97, 95% confidence interval 0.96-0.98 per 1% increase from pre-intervention LA function, P = 0.006) was associated with a lower risk of atrial fibrillation after adjustment for age, sex, pre-intervention LA reservoir strain, and history of atrial fibrillation. CONCLUSION: COA repair resulted in improved LA function and decreased risk for atrial fibrillation, especially in patients without residual hypertension or significant residual COA gradient.

Cardiac Catheterization in Adults with Ebstein Anomaly: Pathophysiologic Insights Regarding Surgical Repair and Prognosis.

The underlying invasive hemodynamics and physiology in Ebstein anomaly (EA) are poorly understood. Moreover, the hemodynamic impact of tricuspid valve intervention in EA has not been well studied. Retrospective cohort of 52 adults with repaired and 36 with unrepaired EA undergoing right heart catheterization at Mayo Clinic, MN between 1993 and 2021. "Repaired" EA was defined as prior tricuspid valve repair and/or replacement (83% post-tricuspid valve replacement). Repaired patients were younger than those with unrepaired EA (41.3 ± 16.0 versus 50.6 ± 15.6 years, p = 0.008) and had a lower prevalence of ≥ moderate native or prosthetic tricuspid regurgitation (67% versus 81%, p = 0.01). Right atrial (RA) pressure was higher among patients with repaired EA than in unrepaired disease [13 (11; 18) versus 10 (8; 15) mmHg; p = 0.02], but these differences were no longer present when adjusting for ≥ moderate right ventricular systolic dysfunction and ≥ moderate tricuspid regurgitation. Cardiac index (Qs) was lower among those with unrepaired EA than in repaired EA (1.9 ± 0.7 versus 2.3 ± 0.6 l/min/m2, p = 0.01), even after adjusting for similar confounders. During a follow-up of 8.6 (3.2-13.3) years, 16 (18%) patients died. Systolic pulmonary artery pressure was independently associated with all-cause mortality. In summary, higher cardiac indices were found in those with repaired EA compared to those with unrepaired disease. RA hypertension was prevalent in both groups and no differences in right filling pressures were found between groups after adjusting for potential confounders. Elevation in pulmonary pressures was independently associated with survival. The use of pulmonary vasomodulators in EA requires further investigation.

Exercise catheterization in adults post-Fontan with normal and abnormal haemodynamic criteria: Insights into normal Fontan physiology.

AIM: The normal (i.e. expected) haemodynamics in adults post-Fontan remain poorly delineated. Moreover, the definitions of elevated exercise pulmonary artery (PA) and PA wedge pressure (PAWP) for this population have not been described. METHODS AND RESULTS: Seventy-two adults post-Fontan undergoing exercise catheterization were categorized into abnormal (Group I, n = 59; defined as resting mean PA ≥14 mmHg and/or PAWP ≥12 mmHg, ΔPAWP/Δsystemic flow [Qs] >2 mmHg/L/min, and/or ΔPA/Δpulmonary flow >3 mmHg/L/min) and normal (Group II, n = 13) haemodynamics. Thirty-nine patients with non-cardiac dyspnoea (NCD) were included as controls. There was no difference in exercise arterial oxygen saturation (87% [81-92] vs. 89% [85-93], p = 0.29), while exercise PA pressure (27 [23-31] vs. 16 [14.5-19.5] mmHg, p < 0.001) and PAWP were higher (21 [18-28] vs. 12 [8-14] mmHg, p < 0.001) in Group I. At peak exercise, Group I had lower heart rate (97 [81-120] vs. 133 [112.5-147.5] bpm, p < 0.001) and Qs response (67.3 [43.8-93.1] vs. 105.9 (82-118.5) % predicted, p < 0.001) than Group II. Exercise superior vena cava pressures were higher (16 [14-22.5] vs. 5.5 [3-7.3] mmHg, p < 0.001) and arterial oxygen saturation lower (89% [85-93] vs. 97% [96-98], p < 0.001) in Group II compared to NCD, while no differences in PAWP, stroke volume index, heart rate, or Qs response were seen. If defined as two standard deviations above mean values for Group II, elevated PAWP and mean PA pressure post-Fontan would correspond to 20.6 mmHg and 25.8 mmHg, respectively. CONCLUSION: PAWP >20 mmHg and mean PA pressure >25 mmHg could be used to define elevated values during exercise in adults post-Fontan. The major discrepancy in exercise haemodynamics among Group II compared to controls appears to be the degree of systemic venous hypertension and arterial desaturation.

Systemic Atrioventricular Valve Surgery in Patients With Congenitally Corrected Transposition of the Great Vessels.

BACKGROUND: Limited data exist regarding the long-term outcomes of systemic atrioventricular valve (SAVV) intervention (morphologic tricuspid valve) in congenitally corrected transposition (ccTGA). OBJECTIVES: The goal of this study was to evaluate the mid- and long-term outcomes of SAVV surgery in ccTGA. METHODS: We performed a retrospective review of 108 ccTGA patients undergoing SAVV surgery from 1979 to 2022. The primary outcome was a composite endpoint of mortality, cardiac transplantation, or ventricular assist device implantation. The secondary outcome was long-term systemic right ventricular ejection fraction (SVEF). Cox proportional hazard and linear regression models were used to analyze survival and late SVEF data. RESULTS: The median age at surgery was 39.5 years (Q1-Q3: 28.8-51.0 years), and the median preoperative SVEF was 39% (Q1-Q3: 33.2%-45.0%). Intrinsic valve abnormality was the most common mechanism of SAVV regurgitation (76.9%). There was 1 early postoperative mortality (0.9%). Postoperative complete heart block occurred in 20 patients (18.5%). The actuarial 5-, 10-, and 20-year freedom from death or transplantation was 92.4%, 79.1%, and 62.9%. The 10- and 20-year freedom from valve reoperation was 100% and 93% for mechanical prosthesis compared with 56.6% and 15.7% for bioprosthesis (P < 0.0001). Predictors of postoperative mortality were age at operation (P = 0.01) and preoperative SVEF (P = 0.04). Preoperative SVEF (P < 0.001), complex ccTGA (P = 0.02), severe SAVV regurgitation (P = 0.04), and preoperative creatinine (P = 0.003) were predictors of late postoperative SVEF. CONCLUSIONS: SAVV surgery remains a valuable option for the treatment of patients with ccTGA, with low early mortality and satisfactory long-term outcomes, particularly in those with SVEF ≥40%. Timely referral and accurate patient selection are the keys to better long-term outcomes.

Prognostic Role of Tricuspid Annular Plane Systolic Excursion/Right Ventricular Systolic Pressure Ratio in Coarctation of Aorta.

Background: Right ventricular (RV) systolic dysfunction and pulmonary hypertension are associated with mortality in adults with coarctation of aorta (COA). The tricuspid annular plane systolic excursion/RV systolic pressure (TAPSE/RVSP) ratio is a validated noninvasive tool for the assessment of RV-pulmonary arterial (RV-PA) coupling in patients with PA hypertension, but similar data are lacking in adults with COA. The purpose of this study was to assess the relationship between the TAPSE/RVSP ratio and outcomes in this population. Methods: A retrospective cohort study of adults with repaired COA was performed. RV systolic dysfunction was defined as RV free wall strain ≥-24% at baseline, whereas new-onset RV systolic dysfunction was defined RV free wall strain ≥-24% during follow-up. Results: Of 661 patients, TAPSE, RVSP, and TAPSE/pulmonary artery systolic pressure ratio were 22 ± 6 mm, 34 ± 12 mm Hg, and 0.71 (0.48-0.89) mm/mm Hg, respectively. Of 661 patients, 152 (23%) had RV systolic dysfunction at baseline, and TAPSE/RVSP <0.43 mm/mm Hg was the optimal threshold to detect RV systolic dysfunction. TAPSE/RVSP <0.43 mm Hg was associated with RV systolic dysfunction (adjusted odds ratio: 3.11 [1.83-6.19], P = 0.004). Of 509 patients with normal RV systolic function, 42 (8%) and 36 (7%) developed new-onset RV systolic dysfunction and new-onset right heart failure, respectively, during follow-up. TAPSE/RVSP <0.43 mm/mm Hg was associated with new-onset RV systolic dysfunction (adjusted hazard ratio: 1.95 [1.46-2.77], P = 0.008) and new-onset right heart failure (adjusted hazard ratio: 0.81 [0.68-0.92], P = 0.005). Conclusions: The TAPSE/RVSP ratio can potentially be used to identify patients at risk for new-onset RV systolic dysfunction and right heart failure and provide opportunity for proactive interventions to prevent adverse outcomes.

Contexte: La dysfonction systolique du ventricule droit (VD) et l'hypertension pulmonaire sont associées à des décès chez les adultes qui présentent une coarctation de l'aorte (CA). Le rapport entre l'excursion systolique du plan de l'anneau tricuspide (TAPSE pour tricuspid annular plane systolic excursion) et la pression systolique du VD (PSVD) est une méthode non invasive pour évaluer le couplage entre le VD et l'artère pulmonaire (VD-AP), qui a été validée chez les patients atteints d'hypertension de l'AP, mais pour laquelle on ne dispose pas de données similaires chez les adultes qui présentent une CA. La présente étude visait à évaluer la relation entre le rapport TAPSE/PSVD et les résultats de santé chez cette population de patients. Méthodologie: Nous avons mené une étude de cohorte rétrospective auprès d'adultes présentant une CA corrigée. La dysfonction systolique du VD était définie comme une déformation (strain) de la paroi libre du VD (DPLVD) ≥ -24 % au début de l'étude, et une dysfonction systolique inaugurale du VD était définie comme une DPLVD ≥ -24 % détectée lors du suivi. Résultats: Pour l'ensemble des 661 patients de l'étude, les valeurs pour la TAPSE, la PSVD et le rapport TAPSE/pression systolique de l'artère pulmonaire étaient respectivement de 22 ± 6 mm, 34 ± 12 mmHg et 0,71 (0,48-0,89) mm/mmHg. Parmi ces 661 patients, 152 (23 %) présentaient initialement une dysfonction systolique du VD, et un rapport TAPSE/PSVD < 0,43 mm/mmHg constituait le seuil optimal pour la détection d'une dysfonction systolique du VD. Un rapport TAPSE/PSVD < 0,43 mm/mmHg était par ailleurs associé à une dysfonction systolique du VD (rapport de cotes ajusté de 3,11 [1,83-6,19], p = 0,004). Au cours du suivi des 509 patients qui présentaient initialement une fonction systolique normale du VD, 42 patients (8 %) ont présenté une dysfonction systolique inaugurale du VD et 36 patients (7 %) ont présenté une insuffisance cardiaque droite inaugurale. Un rapport TAPSE/PSVD < 0,43 mm/mmHg était associé avec la dysfonction systolique inaugurale du VD (rapport des risques instantanés ajusté de 1,95 [1,46-2,77], p = 0,008), et avec l'insuffisance cardiaque droite inaugurale (rapport des risques instantanés ajusté de 0,81 [0,68-0,92], p = 0,005). Conclusions: Le rapport TAPSE/PSVD pourrait permettre de repérer les patients susceptibles de présenter une dysfonction systolique inaugurale du VD ou une insuffisance cardiaque droite inaugurale, ce qui ouvre la voie à des interventions en amont visant à prévenir les résultats défavorables pour ces patients.

Impact of heart failure on reoperation in adult congenital heart disease: An innovative machine learning model.

OBJECTIVES: The study objectives were to evaluate the association between preoperative heart failure and reoperative cardiac surgical outcomes in adult congenital heart disease and to develop a risk model for postoperative morbidity/mortality. METHODS: Single-institution retrospective cohort study of adult patients with congenital heart disease undergoing reoperative cardiac surgery between January 1, 2010, and March 30, 2022. Heart failure defined clinically as preoperative diuretic use and either New York Heart Association Class II to IV or systemic ventricular ejection fraction less than 40%. Composite outcome included operative mortality, mechanical circulatory support, dialysis, unplanned noncardiac reoperation, persistent neurologic deficit, and cardiac arrest. Multivariable logistic regression and machine learning analysis using gradient boosting technology were performed. Shapley statistics determined feature influence, or impact, on model output. RESULTS: Preoperative heart failure was present in 376 of 1011 patients (37%); those patients had longer postoperative length of stay (6 [5-8] vs 5 [4-7] days, P < .001), increased postoperative mechanical circulatory support (21/376 [6%] vs 16/635 [3%], P = .015), and decreased long-term survival (84% [80%-89%] vs 90% [86%-93%]) at 10 years (P = .002). A 7-feature machine learning risk model for the composite outcome achieved higher area under the curve (0.76) than logistic regression, and ejection fraction was most influential (highest mean |Shapley value|). Additional risk factors for the composite outcome included age, number of prior cardiopulmonary bypass operations, urgent/emergency procedure, and functionally univentricular physiology. CONCLUSIONS: Heart failure is common among adult patients with congenital heart disease undergoing cardiac reoperation and associated with longer length of stay, increased postoperative mechanical circulatory support, and decreased long-term survival. Machine learning yields a novel 7-feature risk model for postoperative morbidity/mortality, in which ejection fraction was the most influential.