Stromal Cell-SLIT3/Cardiomyocyte-ROBO1 Axis Regulates Pressure Overload-Induced Cardiac Hypertrophy.

BACKGROUND: Recently shown to regulate cardiac development, the secreted axon guidance molecule SLIT3 maintains its expression in the postnatal heart. Despite its known expression in the cardiovascular system after birth, SLIT3's relevance to cardiovascular function in the postnatal state remains unknown. As such, the objectives of this study were to determine the postnatal myocardial sources of SLIT3 and to evaluate its functional role in regulating the cardiac response to pressure overload stress. METHODS: We performed in vitro studies on cardiomyocytes and myocardial tissue samples from patients and performed in vivo investigation with SLIT3 and ROBO1 (roundabout homolog 1) mutant mice undergoing transverse aortic constriction to establish the role of SLIT3-ROBO1 in adverse cardiac remodeling. RESULTS: We first found that SLIT3 transcription was increased in myocardial tissue obtained from patients with congenital heart defects that caused ventricular pressure overload. Immunostaining of hearts from WT (wild-type) and reporter mice revealed that SLIT3 is secreted by cardiac stromal cells, namely fibroblasts and vascular mural cells, within the heart. Conditioned media from cardiac fibroblasts and vascular mural cells both stimulated cardiomyocyte hypertrophy in vitro, an effect that was partially inhibited by an anti-SLIT3 antibody. Also, the N-terminal, but not the C-terminal, fragment of SLIT3 and the forced overexpression of SLIT3 stimulated cardiomyocyte hypertrophy and the transcription of hypertrophy-related genes. We next determined that ROBO1 was the most highly expressed roundabout receptor in cardiomyocytes and that ROBO1 mediated SLIT3's hypertrophic effects in vitro. In vivo, Tcf21+ fibroblast and Tbx18+ vascular mural cell-specific knockout of SLIT3 in mice resulted in decreased left ventricular hypertrophy and cardiac fibrosis after transverse aortic constriction. Furthermore, α-MHC+ cardiomyocyte-specific deletion of ROBO1 also preserved left ventricular function and abrogated hypertrophy, but not fibrosis, after transverse aortic constriction. CONCLUSIONS: Collectively, these results indicate a novel role for the SLIT3-ROBO1-signaling axis in regulating postnatal cardiomyocyte hypertrophy induced by pressure overload.

Determinants of survival following heart transplantation in adults with congenital heart disease.

BACKGROUND: Adult patients surviving with congenital heart disease (ACHD) is growing. We examine the factors associated with heart transplant outcomes in this challenging population with complex anatomy requiring redo-surgeries. METHODS: We reviewed the United Network for Organ Sharing-Standard Transplant Analysis and Research database and analyzed 35,952 heart transplants from January 1st, 2000, to September 30th, 2018. We compared transplant characteristics for ischemic cardiomyopathy (ICM) (n = 14,236), nonischemic cardiomyopathy (NICM) (n = 20,676), and ACHD (n = 1040). Mean follow-up was 6.20 ± 4.84 years. Kaplan-Meier survival curves and Cox-proportional hazards analysis were used to analyze survival data. RESULTS: Multivariable analysis confirmed that ACHD was associated greater in-hospital death compared to ICM (HR = 0.54, P < 0.001) and NICM (HR = 0.46, P < 0.001). Notable factors associated with increased mortality were history of cerebrovascular disease (HR = 1.11, P = 0.026), prior history of malignancy (HR = 1.12, P = 0.006), pre-transplant biventricular support (HR = 1.12, P = 0.069), postoperative stroke (HR = 1.47, P < 0.001) and postoperative dialysis (HR = 1.71, P < 0.001). ACHD transplants had a longer donor heart ischemic time (P < 0.001) and trend towards more deaths from primary graft dysfunction (P = 0.07). In-hospital deaths were more likely with ACHD and use of mechanical support such as use of right ventricular assist device (HR = 2.20, P = 0.049), biventricular support (HR = 1.62, P < 0.001) and extracorporeal membrane oxygenation (HR = 2.36, P < 0.001). Conditional survival after censoring hospital deaths was significantly higher in ACHD (P < 0.001). CONCLUSION: Heart transplant in ACHD is associated with a higher post-operative mortality given anatomical complexity but a better long-term conditional survival. Normothermic donor heart perfusion may improve outcomes in the ACHD population by reducing the impact of longer ischemic times.

Intrahepatic Transcriptomics Differentiate Advanced Fibrosis and Clinical Outcomes in Adults With Fontan Circulation.

BACKGROUND: The molecular mechanisms underlying Fontan-associated liver disease (FALD) remain largely unknown. OBJECTIVES: This study aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes. METHODS: This retrospective cohort study included adults with the Fontan circulation. Baseline clinical, laboratory, imaging, and hemodynamic data as well as a composite clinical outcome (CCO) were extracted from medical records. Patients were classified into early or advanced fibrosis. RNA was isolated from formalin-fixed paraffin-embedded liver biopsy samples; RNA libraries were constructed with the use of an rRNA depletion method and sequenced on an Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were performed with the use of DESeq2 and Metascape. RESULTS: A total of 106 patients (48% male, median age 31 years [IQR: 11.3 years]) were included. Those with advanced fibrosis had higher B-type natriuretic peptide levels and Fontan, mean pulmonary artery, and capillary wedge pressures. The CCO was present in 23 patients (22%) and was not predicted by advanced liver fibrosis, right ventricular morphology, presence of aortopulmonary collaterals, or Fontan pressures on multivariable analysis. Samples with advanced fibrosis had 228 upregulated genes compared with early fibrosis. Samples with the CCO had 894 upregulated genes compared with those without the CCO. A total of 136 upregulated genes were identified in both comparisons and were enriched in cellular response to cytokine stimulus or oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-ß signaling pathway, and vasculature development. CONCLUSIONS: Patients with FALD and advanced fibrosis or the CCO exhibited upregulated genes related to inflammation, congestion, and angiogenesis.

Center-Level Variation in Failure to Rescue After Pediatric Cardiac Surgery.

BACKGROUND: Although failure to rescue (FTR) is increasingly recognized as a quality metric, studies in congenital cardiac surgery remain sparse. Within a national cohort of children undergoing cardiac operations, we characterized the presence of center-level variation in FTR and hypothesized a strong association with mortality but not complications. METHODS: All children undergoing congenital cardiac operations were identified in the 2013 to 2019 Nationwide Readmissions Database. FTR was defined as in-hospital death after cardiac arrest, ventricular tachycardia/fibrillation, prolonged mechanical ventilation, pneumonia, stroke, venous thromboembolism, or sepsis, among other complications. Hierarchical models were used to generate hospital-specific, risk-adjusted rates of mortality, complications, and FTR. Centers in the highest decile of FTR were identified and compared with others. RESULTS: Of an estimated 74,070 patients, 1.9% died before discharge, at least 1 perioperative complication developed in 43.0%, and 4.1% experienced FTR. After multilevel modeling, decreasing age, nonelective admission, and increasing operative complexity were associated with greater odds of FTR. Variations in overall mortality and FTR exhibited a strong, positive relationship (r = 0.97), whereas mortality and complications had a negligible association (r = -0.02). Compared with others, patients at centers with high rates of FTR had similar distributions of age, sex, chronic conditions, and operative complexity. CONCLUSIONS: In the present study, center-level variations in mortality were more strongly explained by differences in FTR than complications. Our findings suggest the utility of FTR as a quality metric for congenital heart surgery, although further study is needed to develop a widely accepted definition and appropriate risk-adjustment models.

Long-term impact of anatomic subtype in hypoplastic left heart syndrome after Fontan completion.

BACKGROUND: Aortic atresia (AA)/mitral stenosis (MS) is a well-known risk factor for survival after Norwood; however, the effect of anatomical subtypes in those who survive surgical palliation is unknown. METHODS: We performed a retrospective single-center study of patients with classic hypoplastic left heart syndrome (HLHS) who underwent Fontan at our center between August 1989 and July 2017. Clinical outcomes, as well as ventricular and atrioventricular-valve (AVV) function, were determined for each patient, and the effects of HLHS subtype were estimated using multivariable statistical analyses. RESULTS: We included 418 patients with HLHS (AA/mitral atresia [MA] 153, AA/MS 100, aortic stenosis [AS]/MS 154, and AS/MA 11). The median follow-up period was 8.6 (interquartile range, 2.9-15.8) years. Overall transplant-free survival, cumulative incidence of AVV failure, and ventricular failure, which were defined by moderate dysfunction or greater or the necessity of surgical interventions, were 70.1%, 35.9%, and 17.9% at 20 years, respectively. Of the 3 major subtypes, AA/MS was associated with lower survival rate (AA/MA 74.6% vs AS/MS 79.1% vs AA/MS 56.1% at 17 years, P = .04). The subanalysis between AA/MA and AA/MS revealed AA/MS tended to have a greater rate of ventricular failure without a significant difference of AVV failure (AA/MA 11.2% vs AA/MS 26.2% at 17 years, P = .053). CONCLUSIONS: The survival risk of the anatomic subtype AA/MS persisted long term after Fontan completion and was likely due to a greater rate of single ventricle rather than AVV failure. These findings suggest that the abnormal pressure overload condition of the hypoplastic left ventricle created by AA/MS has a detrimental effect on single right ventricle function.

SLIT3-mediated fibroblast signaling: a promising target for antifibrotic therapies.

The SLIT family (SLIT1-3) of highly conserved glycoproteins was originally identified as ligands for the Roundabout (ROBO) family of single-pass transmembrane receptors, serving to provide repulsive axon guidance cues in the nervous system. Intriguingly, studies involving SLIT3 mutant mice suggest that SLIT3 might have crucial biological functions outside the neural context. Although these mutant mice display no noticeable neurological abnormalities, they present pronounced connective tissue defects, including congenital central diaphragmatic hernia, membranous ventricular septal defect, and osteopenia. We recently hypothesized that the phenotype observed in SLIT3-deficient mice may be tied to abnormalities in fibrillar collagen-rich connective tissue. Further research by our group indicates that both SLIT3 and its primary receptor, ROBO1, are expressed in fibrillar collagen-producing cells across various nonneural tissues. Global and constitutive SLIT3 deficiency not only reduces the synthesis and content of fibrillar collagen in various organs but also alleviates pressure overload-induced fibrosis in both the left and right ventricles. This review delves into the known phenotypes of SLIT3 mutants and the debated role of SLIT3 in vasculature and bone. Present evidence hints at SLIT3 acting as an autocrine regulator of fibrillar collagen synthesis, suggesting it as a potential antifibrotic treatment. However, the precise pathway and mechanisms through which SLIT3 regulates fibrillar collagen synthesis remain uncertain, presenting an intriguing avenue for future research.

Survival After Cardiac Transplantation in Adults With Single-Ventricle Congenital Heart Disease.

BACKGROUND: Without large-scale analyses of adults with single-ventricle congenital heart disease (CHD) undergoing heart transplantation, little evidence exists to guide listing practices and patient counseling. OBJECTIVES: This study aims to evaluate survival after heart transplantation in adults with single and biventricular CHD and compare it to that of non-CHD transplant recipients. METHODS: In this 15-year (2005-2020) retrospective analysis, outcome-blinded investigators used probability-linkage to merge the National (Nationwide) Inpatient Sample and Organ Procurement and Transplantation Network data sets. RESULTS: Of 382 adult (≥18 years of age) heart transplant recipients with CHD, 185 (48%) had single-ventricle physiology. Compared to biventricular CHD, single-ventricle patients showed significantly reduced survival at 1 (80% vs 91%; HR: 2.50; 95% CI: 1.40-4.49; P = 0.002) and 10 years (54% vs 71%; HR: 2.10; 95% CI: 1.38-3.18; P < 0.001). Among patients who survived the first post-transplantation year, biventricular CHD patients exhibited similar 10-year survival as single-ventricle patients, except for those with hypoplastic left heart syndrome (79% vs 71%; HR: 1.58; 95% CI: 0.85-2.92; P = 0.15). Additionally, biventricular CHD transplant recipients showed significantly better 10-year conditional survival compared to their non-CHD counterparts (79% vs 68%; HR: 0.73; 95% CI: 0.59-0.90; P = 0.003). CONCLUSIONS: Among adult CHD transplant recipients, single-ventricle physiology correlated with higher short-term mortality. However, 10-year conditional survival was similar for biventricular and most single-ventricle CHD patients, and notably better for biventricular CHD patients compared to non-CHD heart transplant recipients. These findings have significant implications towards patient selection and listing strategies, easing concerns related to heart transplantation in adults with CHD and destigmatizing most subtypes of single-ventricle CHD.

Intrahepatic transcriptomics differentiate advanced fibrosis and clinical outcomes in adults with the Fontan circulation.

Background: The molecular mechanisms underlying Fontan associated liver disease (FALD) remain largely unknown. We aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes. Methods: This retrospective cohort study included adults with the Fontan circulation at the Ahmanson/UCLA Adult Congenital Heart Disease Center. Clinical, laboratory, imaging and hemodynamic data prior to the liver biopsy were extracted from medical records. Patients were classified into early (F1-F2) or advanced fibrosis (F3-F4). RNA was isolated from formalin-fixed paraffin embedded liver biopsy samples; RNA libraries were constructed using rRNA depletion method and sequencing was performed on Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were carried out using DESeq2 and Metascape. Medical records were comprehensively reviewed for a composite clinical outcome which included decompensated cirrhosis, hepatocellular carcinoma, liver transplantation, protein-losing enteropathy, chronic kidney disease stage 4 or higher, or death. Results: Patients with advanced fibrosis had higher serum BNP levels and Fontan, mean pulmonary artery and capillary wedge pressures. The composite clinical outcome was present in 23 patients (22%) and was predicted by age at Fontan, right ventricular morphology and presence of aortopulmonary collaterals on multivariable analysis. Samples with advanced fibrosis had 228 up-regulated genes compared to early fibrosis. Samples with the composite clinical outcome had 894 up-regulated genes compared to those without it. A total of 136 up-regulated genes were identified in both comparisons and these genes were enriched in cellular response to cytokine stimulus, response to oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-beta signaling pathway, and vasculature development. Conclusions: Patients with FALD and advanced liver fibrosis or the composite clinical outcome exhibit up-regulated genes including pathways related to inflammation, congestion, and angiogenesis. This adds further insight into FALD pathophysiology.

Whole-Exome Sequencing Identifies Homozygote Nonsense Variants in LMOD2 Gene Causing Infantile Dilated Cardiomyopathy.

As an essential component of the sarcomere, actin thin filament stems from the Z-disk extend toward the middle of the sarcomere and overlaps with myosin thick filaments. Elongation of the cardiac thin filament is essential for normal sarcomere maturation and heart function. This process is regulated by the actin-binding proteins Leiomodins (LMODs), among which LMOD2 has recently been identified as a key regulator of thin filament elongation to reach a mature length. Few reports have implicated homozygous loss of function variants of LMOD2 in neonatal dilated cardiomyopathy (DCM) associated with thin filament shortening. We present the fifth case of DCM due to biallelic variants in the LMOD2 gene and the second case with the c.1193G>A (p.W398*) nonsense variant identified by whole-exome sequencing. The proband is a 4-month male infant of Hispanic descent with advanced heart failure. Consistent with previous reports, a myocardial biopsy exhibited remarkably short thin filaments. However, compared to other cases of identical or similar biallelic variants, the patient presented here has an unusually late onset of cardiomyopathy during infancy. Herein, we present the phenotypic and histological features of this variant, confirm the pathogenic impact on protein expression and sarcomere structure, and discuss the current knowledge of LMOD2-related cardiomyopathy.

Considerations of valvular heart disease in children with ventricular assist devices.

Ventricular assist devices have become a valuable tool in the treatment of heart failure in children. The use of ventricular assist devices has decreased mortality in children with end-stage heart failure awaiting transplant. It is not uncommon for children with end-stage heart failure associated with cardiomyopathy or congenital heart disease to have significant systemic semilunar and atrioventricular valve regurgitation, which can impact the efficiency and efficacy of hemodynamic support provided by a ventricular assist device. Therefore, implanting clinicians should carefully assess for valve abnormalities that may need repair and impact device selection and cannulation strategy to effectively support this diverse population. The purpose of this review is to provide an overview of this important and relevant topic and to discuss strategies for managing these patients.

Combined Heart-Liver vs Isolated Heart Transplantation in Adults With Congenital Heart Disease.

BACKGROUND: Despite an increasing number of adults with congenital heart disease undergoing combined heart-liver transplantation (CHLT), there is a paucity of literature analyzing posttransplant outcomes. We analyzed the incidence and outcomes of congenital heart disease patients undergoing CHLT compared with those undergoing isolated heart transplantation (HT). METHODS: This was a retrospective analysis of all adult (≥18 years) congenital heart disease patients undergoing CHLT or HT between 2000 and 2020 in the Organ Procurement and Transplantation Network database. The primary outcome was death at 30 days and 1 year after transplantation. RESULTS: Of 1214 recipients included for analysis, 92 (8%) underwent CHLT and 1122 (92%) underwent HT. Patients undergoing CHLT and HT were similar in the distribution of age, sex, and serum bilirubin. Upon adjusted analysis with HT as the reference, undergoing CHLT was associated with a similar hazard of 30-day mortality between 2000 and 2017 (hazard ratio [HR], 0.51; 95% CI, 0.12-2.08; P = .35) and 2018 and 2020 (HR, 2.32; 95% CI, 0.88-6.13; P = .09). Similarly, there was no difference in the hazard of 1-year mortality for patients undergoing CHLT between 2000 and 2017 (HR, 0.60; 95% CI, 0.22-1.63; P = .32) and 2018 and 2020 (HR, 1.52; 95% CI, 0.66-3.53; P = .33) compared with HT. CONCLUSIONS: The number of adults undergoing CHLT continues to rise. Given comparable survival outcomes between CHLT and HT, our findings demonstrate the former as a viable option for complex congenital heart disease patients with failing cavopulmonary circulation and associated liver disease. Future studies should delineate factors associated with early hepatic dysfunction to help identify congenital heart disease patients that would benefit from CHLT.

Report of the 2022 Society of Thoracic Surgeons Congenital Heart Surgery Practice Survey.

BACKGROUND: The Society of Thoracic Surgeons Workforce on Congenital Surgery performed a practice survey to analyze contemporary data. METHODS: An electronic survey was sent to congenital heart surgeons in North America. Details on demographics, training paradigm, clinical practice, and work satisfaction were queried, tabulated, and analyzed. RESULTS: Of 312 unique contacts, 201 (64.4%) responded. Of these, 178 (89%) were practicing. The median age was 52 years (interquartile range, 43, 59 years), and 157 (88%) were male. The number of female respondents increased from 12 (7%) in 2015 to 18 (11%) at present. Practice composition was predominantly mixed pediatric and adult (141; 79%), although 15 (8%) surgeons practiced exclusively pediatric surgery. Most surgeons (154; 87%) reported performing the Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery category 4 and 5 procedures. One-fourth (42; 24%) reported performing fewer than 50 pediatric cases per year, and 18 (10%) stated that their primary role was as a surgical assistant. Individual surgeon case volume was most commonly 100 to 149 total cases (29%). Although one-half (91; 51%) reported their volume as being "just right," 74 (42%) reported that their case volume was "too small." Seventy-six (43%) reported too many surgeons in their region. Of the 201 practicing surgeons, 30 (14.9%) plan retirement in the next 5 years. Most described career satisfaction, with 102 (57%) being very satisfied and 48 (27%) somewhat satisfied. CONCLUSIONS: Although most congenital heart surgeons in North America are satisfied with their careers, more than 40% believe that their caseload is inadequate and that there are too many surgeons in their region. Further analysis is warranted regarding career dissatisfaction and diversity.

Valve-sparing root replacement after the Ross procedure.

OBJECTIVES: The Ross procedure is a preferred treatment for infants and children with aortic valve disease. Progressive neoaortic root dilation and neoaortic insufficiency can occur after the Ross procedure, and because of the young age of these patients, valve-sparing aortic root replacement procedures have advantages compared with the Bentall procedure. The aim of this study is to describe our experience with different techniques of aortic valve-sparing root replacement in this unique cohort of patients. METHODS: Patients undergoing valve-sparing aortic root replacement with a history of the Ross procedure between January 2001 and March 2021 were identified. A retrospective chart review was performed, and clinical characteristics of these patients were analyzed. The results of different types of valve-sparing aortic root replacement were also compared. RESULTS: Forty-two patients who had previously undergone a Ross procedure in childhood presented for reintervention for neoaortic root or valve pathology. Seventeen of these patients were considered for valve-sparing aortic root replacement but underwent bioprosthetic or mechanical valve replacement, and 25 patients underwent successful valve-sparing aortic root replacement. Patients who underwent valve-sparing aortic root replacement received a traditional aortic root remodeling procedure with or without suture annuloplasty (Yacoub technique, group 1, n = 7), an aortic root reimplantation procedure (David technique, group 2, n = 11), or a modified root remodeling procedure that also used a geometric annuloplasty ring (group 3, n = 7). Patient demographics and comorbidities were similar between groups. Mean follow-up for these 3 cohorts was 14 years, 4 years, and 1 year, respectively. Overall survival was good, with 1 early death due to hemorrhage in group 2 and 1 death due to malignancy in group 1. Eight patients (7 in group 1; 1 in group 2) required subsequent aortic valve replacements due to neoaortic insufficiency, whereas none in group 3 have required any reintervention. Overall, patients requiring valve replacement after valve-sparing aortic root replacement had lower grades of preoperative neoaortic insufficiency and higher grades of postoperative neoaortic insufficiency. Greater than mild postoperative neoaortic insufficiency was associated with the need for subsequent neoaortic valve replacement. CONCLUSIONS: Valve-sparing aortic root replacement is safe in patients with a prior Ross procedure. Reimplantation offers superior durability compared with the traditional remodeling procedure. Greater than mild neoaortic insufficiency on postoperative echocardiogram should prompt additional attempts at valve repair. A modified remodeling procedure with geometric ring annuloplasty that is personalized to the patient's individual anatomy is safe with good short-term results, but longer follow-up is needed.

Aortic valve repair using geometric ring annuloplasty in pediatric and congenital heart disease patients.

OBJECTIVE: Existing replacement options for the aortic valve have significant drawbacks, especially in children. A geometric annuloplasty ring can help to achieve consistently successful aortic valve repair, but only limited experience with use of this device has been reported in pediatric and congenital heart disease patients. METHODS: All pediatric and adult congenital patients at our institution who underwent aortic valve repair with placement of a geometric annuloplasty ring were reviewed. The study period spanned from July 2018 to April 2022. Hemodynamic outcomes were evaluated using transthoracic echocardiography. RESULTS: The study included 36 subjects. The median age was 17.4 years (range, 8-30 years). Twenty-one subjects were younger than age 18 years. The most common primary diagnoses were neoaortic valve insufficiency or neoaortic root dilation, and congenital aortic stenosis with bicuspid or functionally unicuspid aortic valve. Of the 34 subjects with procedural success, 31 (91%) had use of additional valve repair techniques and 26 (76%) had an additional concomitant procedure performed. Operative mortality was 0% (0/33), and major complication rate was 6% (2/33). The median follow-up time was 1.9 years (maximum, 3.8 years). The mean grade of aortic insufficiency was signific antly reduced after repair, with no change in mean gradients. Freedom from reoperation over the follow-up period was 97% (33/34), and freedom from ≥3+ recurrent aortic insufficiency was 94% (32/34). CONCLUSIONS: A geometric annuloplasty ring can be used to help achieve consistently successful aortic valve repair with excellent perioperative and follow-up outcomes, even in pediatric and complex congenital heart disease patients.

Determining optimal donor heart ischemic times in adult cardiac transplantation.

OBJECTIVES: Unsupervised statistical determination of optimal allograft ischemic time (IT) on heart transplant outcomes among ABO donor heart types. METHODS: We identified 36,145 heart transplants (2000-2018) from the United Network for Organ Sharing database. Continuous and categorical variables were analyzed with parametric and nonparametric testing. Determination of IT cutoffs for survival analysis was performed using Contal and O'Quigley univariable method and Vito Muggeo multivariable segmented modeling. RESULTS: Univariable and multivariable IT threshold determination revealed a cutoff at about 3 h. The hourly increase in survival risk with ≥3 h IT is asymmetrically experienced at the early 90 days (hazard ratio [HR] = 1.29, p < .001) and up to 1-year time point (HR = 1.16, p < .001). Beyond 1 year the risk of prolonged IT is less impactful (HR = 1.04, p = .022). Longer IT was associated with more postoperative complications such as stroke (2.7% vs. 2.3, p = .042), dialysis (11.6% vs. 9.1%, p < .001) and death from primary graft dysfunction (1.8% vs. 1.2%, p < .001). O blood type donor hearts with IT ≥ 3 h has significantly increased hourly mortality risk at 90 days (HR = 1.27, p < .001), 90 days to 1 year (HR = 1.22, p < .001) and >1 year (HR = 1.05, p = .041). For non-O blood types with ≥3 h IT hourly mortality risk was increased at 90 days (HR = 1.33, p < .001), but not at 90 days to 1 year (HR = 1.09, p = .146) nor ≥1 year (HR = 1.08, p = .237). CONCLUSIONS: The donor heart IT threshold for survival determined from unbiased statistical modeling occurs at 3 h. With longer preservation times, transplantation with O donor hearts was associated with worse survival.

Autologous Cardiac Stem Cell Injection in Patients with Hypoplastic Left Heart Syndrome (CHILD Study).

Mortality in infants with hypoplastic left heart syndrome (HLHS) is strongly correlated with right ventricle (RV) dysfunction. Cell therapy has demonstrated potential improvements of RV dysfunction in animal models related to HLHS, and neonatal human derived c-kit+ cardiac-derived progenitor cells (CPCs) show superior efficacy when compared to adult human cardiac-derived CPCs (aCPCs). Neonatal CPCs (nCPCs) have yet to be investigated in humans. The CHILD trial (Autologous Cardiac Stem Cell Injection in Patients with Hypoplastic Left Heart Syndrome) is a Phase I/II trial aimed at investigating intramyocardial administration of autologous nCPCs in HLHS infants by assessing the feasibility, safety, and potential efficacy of CPC therapy. Using an open-label, multicenter design, CHILD investigates nCPC safety and feasibility in the first enrollment group (Group A/Phase I). In the second enrollment group, CHILD uses a randomized, double-blinded, multicenter design (Group B/Phase II), to assess nCPC efficacy based on RV functional and structural characteristics. The study plans to enroll 32 patients across 4 institutions: Group A will enroll 10 patients, and Group B will enroll 22 patients. CHILD will provide important insights into the therapeutic potential of nCPCs in patients with HLHS.Clinical Trial Registration https://clinicaltrials.gov/ct2/home NCT03406884, First posted January 23, 2018.

Early Outcomes of Patients Undergoing Neoaortic Valve Repair Incorporating Geometric Ring Annuloplasty.

OBJECTIVES: During congenital heart surgery, the pulmonary valve and root may be placed into the systemic position, yielding a "neoaortic" valve. With the stress of systemic pressure, the pulmonary roots can dilate, creating aneurysms and/or neoaortic insufficiency (neoAI). This report analyzes the early outcomes of patients undergoing neoaortic valve repair incorporating geometric ring annuloplasty. METHODS: Twenty-one patients underwent intended repair at six centers and formed the study cohort. Thirteen had previous Ross procedures, five had arterial switch operations, and three Fontan physiology. Average age was 21.7 ± 12.8 years (mean ± SD), 80% were male, and 11 (55%) had symptomatic heart failure. Preoperative neoAI Grade was 3.1 ± 1.1, and annular diameter was 30.7 ± 6.5 mm. RESULTS: Valve repair was accomplished in 20/21, using geometric annuloplasty rings and leaflet plication (n = 13) and/or nodular release (n = 7). Fourteen had neoaortic aneurysm replacement (13 with root remodeling). Two underwent bicuspid valve repair. Six had pulmonary conduit changes, one insertion of an artificial Nodulus Arantius, and one resection of a subaortic membrane. Ring size averaged 21.9 ± 2.3 mm, and aortic clamp time was 171 ± 54 minutes. No operative mortality or major morbidity occurred, and postoperative hospitalization was 4.3 ± 1.4 days. At discharge, neoAI grade was 0.2 ± 0.4 (P < .0001), and valve mean gradient was ≤20 mm Hg. At average 18.0 ± 9.1 months of follow-up, all patients were asymptomatic with stable valve function. CONCLUSIONS: Neoaortic aneurysms and neoAI are occasionally seen late following Ross, arterial switch, or Fontan procedures. Neoaortic valve repair using geometric ring annuloplasty, leaflet reconstruction, and root remodeling provides a patient-specific approach with favorable early outcomes.