Heart failure after the Norwood procedure: An analysis of the Single Ventricle Reconstruction Trial

Prolonged Inotrope Use After Surgery for Congenital Heart Disease: A Common Occurrence with a High Burden of Mortality

Outcomes in patients requiring prolonged inotropes (PI) following surgery for congenital heart disease (CHD) have not been well studied. We aimed to describe the burden of PI use in the immediate postoperative period after CHD surgery and identify risk factors for in-hospital mortality. We conducted a retrospective cohort study using the Pediatric Health Information System® (PHIS) database. Patients 0-18 years with CHD who underwent cardiovascular surgery from 2010 to 2020 were included. Patients who received inotropic medications for > 7 consecutive days after surgery were in the PI group and all others in the control group. Patients who died before 7 days were excluded. Multivariable mixed-effect logistic regression was used to examine risk factors for in-hospital mortality. There were 110,271 patients from 48 centers included, 10,292 in the PI group and 99,979 in the control group. In-hospital mortality was significantly higher in the PI group (24.9% vs. 4.6%, p < 0.001). Ventricular assist device use was rare (1.6%). After adjustment, odds of in-hospital mortality in the PI group was 3.5 (95% CI 3.3-3.8) times higher than in controls. Independent risk factors for in-hospital mortality were age, non-White race, class of CHD, number of complex chronic conditions, preoperative inotrope, preoperative extracorporeal membrane oxygenation, sepsis, stroke, renal failure, number of inotropes at 7 days, and discharge year (p < 0.01 for all). Postoperative PI use in CHD is common and carries a considerable burden of mortality. Additional work is needed to understand which risk factors are modifiable and which patients may benefit from reintervention or advanced heart failure therapies.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Evaluation and Management of Chronic Heart Failure in Children and Adolescents With Congenital Heart Disease: A Scientific Statement From the American Heart Association

With continued medical and surgical advancements, most children and adolescents with congenital heart disease are expected to survive to adulthood. Chronic heart failure is increasingly being recognized as a major contributor to ongoing morbidity and mortality in this population as it ages, and treatment strategies to prevent and treat heart failure in the pediatric population are needed. In addition to primary myocardial dysfunction, anatomical and pathophysiological abnormalities specific to various congenital heart disease lesions contribute to the development of heart failure and affect potential strategies commonly used to treat adult patients with heart failure. This scientific statement highlights the significant knowledge gaps in understanding the epidemiology, pathophysiology, staging, and outcomes of chronic heart failure in children and adolescents with congenital heart disease not amenable to catheter-based or surgical interventions. Efforts to harmonize the definitions, staging, follow-up, and approach to heart failure in children with congenital heart disease are critical to enable the conduct of rigorous scientific studies to advance our understanding of the actual burden of heart failure in this population and to allow the development of evidence-based heart failure therapies that can improve outcomes for this high-risk cohort.

Morphology of the native ascending aorta after the Norwood procedure for aortic atresia: impact on survival and right ventricular dysfunction

OBJECTIVES

Our goal was to evaluate the impact of variable morphology of the native ascending aorta after the Norwood I procedure in patients with hypoplastic left heart syndrome/aortic atresia on long-term survival and systemic right ventricular dysfunction.

METHODS

Of 151 survivors of the Norwood procedure for hypoplastic left heart syndrome/aortic atresia at our institution between January 2001 and December 2020, we included patients with available and measurable aortograms prior to stage II palliation. The diameter of the native ascending aorta, the length of the native ascending aorta and the angle between the native ascending aorta and the proximal pulmonary artery were measured. We investigated the impact of these morphologic parameters on mortality and on right ventricular dysfunction (defined as at least moderate).

RESULTS

Angiograms were available for 78 patients. The median diameter of the native ascending aorta was 3.2 mm (2.6-3.7), the median length of the native ascending aorta was 15.4 mm (13.3-17.9) and the median angle between the native ascending aorta and the proximal pulmonary artery was 44° (35°-51°). During the median follow-up of 6.5 years, 8 (10%) patients died and systemic right ventricular dysfunction occurred in 19 patients (24%). No significant association between aortic morphology and mortality could be detected. Right ventricular function was negatively affected by a larger angle between the native ascending aorta and the proximal pulmonary artery [odds ratio 1.07 (1.01-1.14), P = 0.02].

CONCLUSIONS

In survivors of the Norwood procedure for hypoplastic left heart syndrome/aortic atresia with available angiograms, no significant association between native aortic morphology and mortality could be demonstrated after stage II palliation, within the scope of this limited study. A larger anastomosis angle between the native ascending aorta and the proximal pulmonary artery emerged as a risk factor for right ventricular dysfunction.

Single Ventricular Assist Device Care and Outcomes for Failed Stage I Palliation: A Single-Center Decade of Experience

Single ventricular assist device (SVAD) use before and after stage I palliation (S1P) is increasing with limited data on outcomes. To address this knowledge gap, we conducted a single-center retrospective review to assess pre- and post-SVAD clinical status, complications, and outcomes. We leveraged a granular, longitudinal, local database that captures end-organ support, procedural interventions, hematologic events, laboratory data, and antithrombotic strategy. We identified 25 patients between 2013 and 2023 implanted at median age of 53 days (interquartile range [IQR] = 16-130); 80% had systemic right ventricles and underwent S1P. Median SVAD days were 54 (IQR = 29-86), and 40% were implanted directly from ECMO. Compared to preimplant, there was a significant reduction in inotrope use ( p = 0.013) and improved weight gain ( p = 0.008) post-SVAD. Complications were frequent including bleeding (80%), stroke (40%), acute kidney injury (AKI) (40%), infection (36%), and unanticipated catheterization (56%). Patients with in-hospital mortality had significantly more bleeding complications ( p = 0.02) and were more likely to have had Blalock-Thomas-Taussig shunts pre-SVAD ( p = 0.028). Survival to 1 year postexplant was 40% and included three recovered and explanted patients. At 1 year posttransplant, all survivors have technology dependence or neurologic injury. This study highlights the clinical outcomes and ongoing support required for successful SVAD use in failed single-ventricle physiology before or after S1P.

Multiscale insights into postnatal aortic development

Despite its vital importance for establishing proper cardiovascular function, the process through which the vasculature develops and matures postnatally remains poorly understood. From a clinical perspective, an ability to mechanistically model the developmental time course in arteries and veins, as well as to predict how various pathologies and therapeutic interventions alter the affected vessels, promises to improve treatment strategies and long-term clinical outcomes, particularly in pediatric patients suffering from congenital heart defects. In the present study, we conducted a multiscale investigation into the postnatal development of the murine thoracic aorta, examining key allometric relations as well as relationships between in vivo mechanical stresses, collagen and elastin expression, and the gradual accumulation of load-bearing constituents within the aortic wall. Our findings suggest that the production of fibrillar collagens in the developing aorta associates strongly with the ratio of circumferential stresses between systole and diastole, hence emphasizing the importance of a pulsatile mechanobiological stimulus. Moreover, rates of collagen turnover and elastic fiber compaction can be inferred directly by synthesizing transcriptional data and quantitative histological measurements of evolving collagen and elastin content. Consistent with previous studies, we also observed that wall shear stresses acting on the aorta are similar at birth and in maturity, supporting the hypothesis that at least some stress targets are established early in development and maintained thereafter, thus providing a possible homeostatic basis to guide future experiments and inform future predictive modeling.

School age and adolescent heart failure following the Norwood procedure

BACKGROUND

Heart failure results in significant morbidity and mortality for young children with hypoplastic left heart syndrome (HLHS) following the Norwood procedure. The trajectory in later childhood is not well described.

METHODS

We studied the outcome into adolescence of participants enrolled in the Single Ventricle Reconstruction trial who underwent the Fontan procedure or survived to 6 years without having undergone Fontan procedure. The primary outcome was heart failure events, defined as heart transplant listing or death attributable to heart failure. Symptomatic heart failure for participants surviving 10 or more years was also assessed utilizing the Pediatric Quality of Life Inventory (PedsQL).

RESULTS

Of the 345 participants who underwent a Fontan operation or survived to 6 years without Fontan, 25 (7.2%) had a heart failure event before the age of 12 years. Among these, 21 were listed for heart transplant, and 4 died from heart failure. Nineteen participants underwent heart transplant, all of whom survived to age 12 years. Factors associated with a heart failure event included longer Norwood hospital length of stay, aortic atresia, and no Fontan operation by age 6 years. Assessment of heart failure symptoms at 12 years of age revealed that 24 (12.2%) of 196 PedsQL respondents "often" or "almost always" had difficulty walking more than one block.

CONCLUSIONS

Heart failure events occur in over 5% of children with palliated HLHS between preschool age and adolescence. Outcomes for children listed for transplant are excellent. However, a substantial portion of palliated HLHS children have significant symptoms of heart failure at 12 years of age.

Combined ventricular dysfunction and atrioventricular valve regurgitation after the Norwood procedure are associated with attrition prior to superior cavopulmonary connection

Background

Infants with hypoplastic left heart syndrome (HLHS) or a variant are at risk of ventricular dysfunction (VD) and atrioventricular valve regurgitation (AVVR) prior to superior cavopulmonary connection (SCPC). Although the impact of these complications in isolation has been described, their effect in combination on attrition is poorly defined.

Methods

A retrospective observational study of patients with HLHS or variants undergoing a Norwood procedure between 2008 and 2020 at a single center was performed. VD and AVVR were defined as moderate or severe when seen on 2 sequential echocardiograms outside the perioperative period. Attrition was defined as death, listing for heart transplant, or unsuitability for SCPC or transplant. Descriptive statistics and regression models were used for analysis.

Results

A total of 397 patients were included, of whom 75% had HLHS and 57% had received a Blalock-Thomas-Taussig shunt. Isolated VD occurred in 9% of patients, AVVR occurred in 13%, and both occurred in 6%. Attrition prior to SCPC occurred in 19% of the overall cohort, in 52% of patients with combined VD and AVVR (odds ratio [OR], 5.2; 95% confidence interval [CI], 2.3-12.0; P < .01), 26% of those with VD (OR, 1.5; 95% CI, 0.7-3.3; P = .32), 25% of those with AVVR (OR, 1.5; 95% CI, 0.7-2.9; P = .27), and 15% in those with neither (OR, 0.3; 95% CI, 0.2-0.6; P < .01). Other factors associated with attrition included prematurity, total bypass time at Norwood, and extracorporeal membrane oxygenation after Norwood, whereas later year of Norwood was protective (P < .01 for all).

Conclusions

The presence of combined VD and AVVR markedly increases the likelihood of attrition prior to SCPC, identifying a high-risk group.

Tricuspid Valve Repair Can Restore the Prognosis of Patients with Hypoplastic Left Heart Syndrome and Tricuspid Valve Regurgitation: A Meta-analysis

To date, evidence supporting the efficacy of tricuspid valve (TV) repair in interrupting the progression of systemic right ventricular (RV) adverse remodeling in hypoplastic left heart syndrome (HLHS) is conflicting. We conducted a systematic review and meta-analysis of scientific literature to assess the impact of TV repair in effectively modifying the prognosis of patients with HLHS. We conducted a systematic review of PubMed, Web of Science, and Scopus databases. A random-effect meta-analysis was performed and transplant-free survival, freedom from TV regurgitation, and TV reoperation data were reconstructed using the published Kaplan-Meier curves. Nine studies were included, comprising 203 HLHS patients undergoing TV repair and 323 HLHS controls. The estimated transplant-free survival at 1, 5, and 10 years of follow-up was 75.5% [95% confidence interval (CI) = 67.6-84.3%], 63.6% [95% CI = 54.6-73.9%], and 61.9% [95% CI = 52.7-72.6%], respectively. Transplant-free survival was comparable to HLHS peers without TV regurgitation (p = 0.59). Five-year freedom from recurrence of TV regurgitation and freedom from TV reoperation was 57% [95% CI = 46.7-69.7%] and 63.6% [95% CI = 54.5-74.3%], respectively. Younger age and TV repair at the time of Norwood operation increased the risk of TV regurgitation recurrence and the need for TV reoperation. Our meta-analysis supports the efficacy of TV repair in favorably modifying the prognosis of patients with HLHS and TV regurgitation, reestablishing a medium-term transplant-free survival which is comparable to HLHS peers. However, durability of surgery and long-term fate of TV and RV performance are still unclear.

Expanding heart transplantation in 2022 and beyond

PURPOSE OF REVIEW

Despite advances in the technology of mechanical circulatory support, the need for heart transplantation continues to grow. The longevity of heart transplants continues to be superior to mechanical solutions, though the short-term differences are shrinking. In this review, we cover three timely developments and summarize the recent literature.

RECENT FINDINGS

After stagnant rates of heart transplant activity for some years, recently, transplant volume has increased. The developments that have ignited interest have been the use of hepatitis C infected donors, which can now be safely transplanted with the advent of curative oral regimens, and the worldwide use of donors following withdrawal of life support as opposed to traditional brain death donors. In addition, the recent experience of human cardiac xenotransplantation has been very exciting, and though it is not of clinical utility yet, it holds the promise for a virtually unlimited supply of organs at some time in the future.

SUMMARY

Much work remains to be done, but together, all three of these developments are exciting and important to be aware of in the future. Each will contribute to additional donors for human heart transplantation and hopefully will alleviate suffering and death on the waiting list.

Ability of the Right Ventricle to Serve as a Systemic Ventricle in Response to the Volume Overload at the Neonatal Stage

BACKGROUND

In children with hypoplastic left heart syndrome (HLHS), volume overload (VO) is inevitable, and the right ventricle (RV) pumps blood into the systemic circulation. Understanding the molecular differences and their different responses to VO between the RV and left ventricle (LV) at the neonatal and highly plastic stages may improve the long-term management of children with HLHS.

METHODS AND RESULTS

A neonatal rat ventricular VO model was established by the creation of a fistula between the inferior vena cava and the abdominal aorta on postnatal day 1 (P1) and confirmed by echocardiographic and histopathological analyses. Transcriptomic analysis demonstrated that some of the major differences between a normal neonatal RV and LV were associated with the thyroid hormone and insulin signaling pathways. Under the influence of VO, the levels of insulin receptors and thyroid hormone receptors were significantly increased in the LV but decreased in the RV. The transcriptomic analysis also demonstrated that under the influence of VO, the top two common enriched pathways between the RV and LV were the insulin and thyroid hormone signaling pathways, whereas the RV-specific enriched pathways were primarily associated with lipid metabolism and arrhythmogenic right ventricular cardiomyopathy (ARVC); further, the LV-specific enriched pathways were primarily associated with nucleic acid metabolism and microRNAs in cancer.

CONCLUSIONS

Insulin and thyroid hormones may play critical roles in the differences between a neonatal RV and LV as well as their common responses to VO. Regarding the isolated responses to VO, the RV favors an ARVC change and the LV favors a reduction in microRNAs in cancer. The current study suggests that insulin, thyroid hormone, and cancer-associated microRNAs are potential therapeutic targets that should be explored by basic science studies to improve the function of the RV to match that of the LV.

Ventricular Assist Device Outcomes in Infants and Children With Stage 1 Single Ventricle Palliation

Data on ventricular assist device (VAD) outcomes in infants with stage 1 single ventricle (SV) palliation are limited. We examined the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry for outcomes of pre/poststage 1 SV patients undergoing VAD implantation between March 2018 and October 2020. Data are collected from 32 centers and major adverse events undergo central adjudication. During the study period, 30 stage 1 SV patients underwent VAD implant with median age of 0.9 months (range 0.1-25) and weight 3.7 kg (2.4-17). Preimplant illness severity was high: ventilator support (90%), ECMO (30%), prior cerebral vascular accident (CVA, 23%), and dialysis (13%). Devices used included paracorporeal pulsatile (50%), paracorporeal continuous-flow (37%), and multiple devices (13%). Median support duration was 56 days (range 3-246). A positive clinical outcome (transplanted or weaned) was attained in 63% (63% transplanted, 37% mortality, 0% weaned). VAD adverse events included: major infection (43%), neurologic dysfunction (any = 30%; CVA = 20%), major bleeding (17%), renal dysfunction (13%), and device malfunction (3%). In conclusion, stage 1 SV patients undergoing VAD support have high preimplant illness severity and complexity, as well as significant morbidity and mortality postimplant. A variety of devices and strategies are employed by centers to support this challenging population.

Relation of Right Atrial Strain to Mortality in Infants With Single Right Ventricles

We explored associations of surveillance testing in infants with single right ventricle (sRV) physiology with clinical outcomes. This prospective, single-center study included patients with sRV who had initial palliative surgery (September 2019 to December 2020). Echocardiograms and B-type naturetic peptide (BNP) obtained as a pair within 24 hours as part of clinical care were included. The primary outcome was death/heart transplant. Secondary outcomes included interstage duration of milrinone use, hospital length of stay, and no digoxin use. sRV functional assessment (subjective grade, fractional area change, tricuspid annular plane systolic excursion, global longitudinal strain, right atrial strain [RAS]) was performed offline. Associations between echocardiography, BNP, and clinical outcomes were determined. Of 26 subjects (47 encounters), 20 had hypoplastic left heart syndrome (77%). Median age at data collection was 50 days (interquartile range 26 to 90). In most encounters (73%), sRV function was subjectively normal. Median BNP was 332 pg/ml (interquartile range 160 to 1,085). A total of 5 patients (19%) met the primary outcome and had lower RAS (14.1 vs 21.3, p = 0.038), but all other parameters were similar to transplant-free survivors. RAS (16.1%, 0.83) had the highest area under curve, followed by global longitudinal strain (-14.4%, 0.77). Higher RAS was associated with fewer days on milrinone (coefficient -1.37, 95% confidence interval [CI] -2.54 to -0.20, p = 0.02) and higher odds of digoxin use (odds ratio 1.09, 95% CI 1.01 to 1.18, p = 0.047). Higher BNP was only associated with a lower odds of digoxin use (odds ratio 0.69, 95% CI 0.5 to 0.96, p = 0.03). In conclusion, RAS is a potentially important imaging marker in infants with sRV and merits further investigation in larger studies.

Association Between Digoxin Use and Cardiac Function in Infants With Single-Ventricle Congenital Heart Disease During the Interstage Period

OBJECTIVES

To examine the association between digoxin use and cardiac function assessed by echocardiographic indices in infants with single-ventricle (SV) congenital heart disease (CHD) during the interstage period.

DESIGN

Retrospective cohort study.

SETTING

Fifteen North American hospitals.

PATIENTS

Infants discharged home following stage 1 palliation (S1P) and prior to stage 2 palliation (S2P). Infants with no post-S1P and pre-S2P echocardiograms were excluded.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 373 eligible infants who met inclusion criteria, 140 (37.5%) were discharged home on digoxin. In multivariable linear and logistic regressions, we found that compared with infants discharged home without digoxin, those discharged with digoxin had a smaller increase in end-systolic volume (β = -8.17 [95% CI, -15.59 to -0.74]; p = 0.03) and area (β = -1.27 [-2.45 to -0.09]; p = 0.04), as well as a smaller decrease in ejection fraction (β = 3.38 [0.47-6.29]; p = 0.02) and fractional area change (β = 2.27 [0.14-4.41]; p = 0.04) during the interstage period.

CONCLUSIONS

Digoxin may partially mitigate the expected decrease in cardiac function during the interstage period through its positive inotropic effects. Prospective clinical trials are needed to establish the pharmacokinetics, safety, and efficacy of digoxin use in SV CHD.

Surgical Strategies in Single Ventricle Management of Neonates and Infants

No area of congenital heart disease has undergone greater change and innovation than Single Ventricle management over the past 20 years. Surgical and catheter lab interventions have transformed outcomes such that in some subgroups more than 80% of these patients can survive into adulthood. Driven by parallel development in diagnostic imaging and cardiac intensive care, surgical management is focused on the neonatal period as the key time to creating a balanced circulation and limiting pulmonary blood-flow. Different configurations of the circulation including new types of surgical shunts and the role of 'hybrid' circulations provide greater options and better physiology. This overview will focus on these changes in surgical management and timing but also look at the exciting areas of regenerative therapies to improve ventricular function, and the concept of ventricular rehabilitation to achieve biventricular circulations in certain groups of patients. The importance of early (neonatal) intervention and multidisciplinary approach to management is emphasised, as well as looking beyond simply survival but also improving neurodevelopmental outcomes.

Long-Term Risk of Heart Failure-Related Death and Heart Transplant After Congenital Heart Surgery in Childhood (from the Pediatric Cardiac Care Consortium)

We aimed to describe the longitudinal risk of advanced heart failure (HF) leading to death, heart transplantation, or ventricular assist device (VAD) placement after congenital heart surgery (CHS) and how it varies across the spectrum of congenital heart disease. We linked the records of patients who underwent first CHS in the Pediatric Cardiac Care Consortium between 1982 and 2003 with the United States National Death Index and Organ Procurement and Transplantation Network databases. Primary outcome was time from CHS discharge to HF-related death, heart transplant, or VAD placement, analyzed with proportional hazards models accounting for competing mortality. In 35,610 patients who survived a first CHS, there were 799 HF deaths, transplants, or VADs over a median of 23 years (interquartile range, 19 to 27). Cumulative incidence at 25 years was 2.3% (95% confidence interval [CI] 2.1% to 2.4%). Compared to mild 2-ventricle defects, the adjusted subhazard ratio for moderate and severe 2-ventricle defects was 3.21 (95% CI 2.28 to 4.52) and 9.46 (95% CI 6.71 to 13.3), respectively, and for single-ventricle defects 31.8 (95% CI 22.2 to 45.6). Systemic right ventricle carried the highest risk 2 years after CHS (subhazard ratio 2.76 [95% CI 2.08 to 3.68]). All groups had higher rates of HF-related death compared with the general population (cause-specific standardized mortality ratio 56.1 [95% CI 51.0 to 61.2]). In conclusion, the risk of advanced HF leading to death, transplantation, or VAD was high across the spectrum of congenital heart disease. While severe defects carry the highest risk, those with mild disease are still at greater risk than the general population.

Systemic ventricular assist device support of the Fontan circulation yields promising outcomes: An analysis of The Society of Thoracic Surgeons Pedimacs and Intermacs Databases

BACKGROUND

Outcomes of ventricular assist device (VAD) support in patients with Fontan circulatory failure (or failing Fontan physiology) are largely unknown.

METHODS

We conducted a retrospective analysis of patients with a Fontan circulation who underwent VAD implant in the Society of Thoracic Surgeons Pedimacs and Intermacs Databases from September 19, 2012, to December 31, 2019.

RESULTS

We identified 55 Fontan patients who had undergone VAD implant with a median age at implantation of 10.2 years (interquartile range, 6.4-16.9 years) and weight, 26.8 kg (interquartile range, 17.7-53.8 years). More VADs were implanted in 2018-2019 than in 2012-2017 (28 vs 27; P = .01). The later era had higher pre-VAD glomerular filtration rate (101.1 ± 48.5 vs 71.2 ± 34.9; P = .02); there was no difference in Interagency Registry for Mechanically Assisted Circulatory Support profile (P = .69). Kaplan-Meier survival on device was 76% at 6 months with no difference by era. Competing outcomes demonstrated a positive outcome of 81% (alive on VAD, transplanted, or recovered) at 6 months, with 58% of mortality occurring during month 1. Median length of support was 3.8 months (interquartile range, 0.6-6.9 months). Five patients were supported for >1 year with no added mortality; the longest support time was 4 years, 7 months. Adverse event rates included pump thrombosis incidence of 4% (3.3 out of 100 patient-months), stroke 5.5% (1.4 out of 100 patient-months), gastrointestinal bleeding of 7% (2.6 out of 100 patient-months), and nongastrointestinal bleeding of 9% (2.3 out of 100 patient-months).

CONCLUSIONS

This is the largest reported analysis of systemic VAD support of Fontan patients. VAD support of the Fontan circulation is becoming more frequent. This analysis demonstrates that VAD use in this growing population can yield promising outcomes.

Pathways to Clinical Cardiac Xenotransplantation

Heart transplantation is the only long-lasting lifesaving option for patients with terminal cardiac failure. The number of available human organs is however far below the actual need, resulting in substantial mortality of patients while waiting for a human heart. Mechanical assist devices are used to support cardiac function but are associated with a high risk of severe complications and poor quality of life for the patients. Consistent success in orthotopic transplantation of genetically modified pig hearts into baboons indicates that cardiac xenotransplantation may become a clinically applicable option for heart failure patients who cannot get a human heart transplant. In this overview, we project potential paths to clinical cardiac xenotransplantation, including the choice of genetically modified source pigs; associated requirements of microbiological, including virological, safety; optimized matching of source pig and recipient; and specific treatments of the donor heart after explantation and of the recipients. Moreover, selection of patients and the regulatory framework will be discussed.

Unique Challenges of Randomised Controlled Trials in Pediatric Cardiology

Pediatric cardiology has evolved over time with reductions in childhood mortality due to congenital heart disease. Surgical innovation drove early changes in care. Increasingly, the need for more robust evidence provided by randomised controlled trials (RCTs) has been recognised. Although the number of RCTs has increased, there remains a relative paucity of truly impactful trials in the field. However, those trials that have changed practice have demonstrated the potential and importance of this work. Examples include the PRIMACORP trial, which established the safety and efficacy of milrinone after cardiac surgery, and the Single Ventricle Reconstruction trial, which was the first multicentre pediatric cardiac surgical RCT. The successful conduct and important findings emanating from these trials serve as beacons as clinicians strive to improve the evidence base in this field. The establishment of national and international networks such as the Pediatric Heart Network and the Canadian Pediatric Cardiology Research Network provide a strong foundation for future collaborative work. Despite this progress, there remain important challenges to designing and executing RCTs in pediatric cardiology. These include issues of greater disease and patient heterogeneity and increased costs. The use of innovative study designs and analytic methods and the establishment of core outcome measures have the potential to overcome some of the issues related to the smaller patient numbers compared with adult disciplines. As pediatric cardiologists look to the future, it is imperative that we work together to derive the maximum benefit from the considerable efforts directed toward conducting impactful clinical trials in pediatric cardiology.

The Genetically Engineered Heart as a Bridge to Allotransplantation in Infants Just Around the Corner?

BACKGROUND

Mortality for infants on the heart transplant wait list remains unacceptably high, and available mechanical circulatory support is suboptimal. Our goal is to demonstrate the feasibility of utilizing genetically engineered pig (GEP) heart as a bridge to allotransplantation by transplantation of a GEP heart in a baboon.

METHODS

Four baboons underwent orthotopic cardiac transplantation from GEP donors. All donor pigs had galactosyl-1,3-galactose knocked out. Two donor pigs had human complement regulatory CD55 transgene and the other 2 had human complement regulatory CD46 and thrombomodulin. Induction immunosuppression included thymoglobulin, and Anti-CD20. Maintenance immunosuppression was Rapamycin, AntiCD-40 and methylprednisolone. One donor heart was preserved with University of Wisconsin (UW) solution and the other three with del Nido solution.

RESULTS

All baboons weaned from cardiopulmonary bypass. B217 received a donor heart preserved with UW. Ventricular arrhythmias and depressed cardiac function resulted in early death. All recipients of del Nido preserved hearts easily weaned from cardiopulmonary bypass with minimal inotropic support. B15416 and B1917 survived for 90 days and 241 days respectively. Histopathology in B15416 revealed no significant myocardial rejection but cellular infiltrate around Purkinje fibers. Histopathology in B1917 was consistent with severe rejection. B37367 had uneventful transplant but developed significant respiratory distress with a cardiac arrest.

CONCLUSIONS

Survival of B15416 and B1917 demonstrates the feasibility of pursuing additional research to document the ability to bridge an infant to cardiac allotransplant with a GEP heart.

Rehabilitation in Pediatric Heart Failure and Heart Transplant

Survival of pediatric patients with heart failure has improved due to medical and surgical advances over the past decades. The complexity of pediatric heart transplant patients has increased as medical and surgical management for patients with congenital heart disease continues to improve. Quality of life in patients with heart failure and transplant might be affected by the impact on functional status that heart failure, heart failure complications or treatment might have. Functional areas affected might be motor, exercise capacity, feeding, speech and/or cognition. The goal of rehabilitation is to enhance and restore functional ability and quality of life to those with physical impairments or disabilities. Some of these rehabilitation interventions such as exercise training have been extensively evaluated in adults with heart failure. Literature in the pediatric population is limited yet promising. The use of additional rehabilitation interventions geared toward specific complications experienced by patients with heart failure or heart transplant are potentially helpful. The use of individualized multidisciplinary rehabilitation program that includes medical management, rehabilitation equipment and the use of physical, occupational, speech and feeding therapies can help improve the quality of life of patients with heart failure and transplant.

A milestone in congenital cardiac surgery: Four decades of the Norwood procedure

Hypoplastic left heart syndrome (HLHS) was first described by Lev in 1952, but it was not until 1958 that it received a name from Noonan and Nadas. For the next several decades, the defect was considered untreatable. In 1979, William Norwood and his colleagues from Boston initiated a program to evaluate staged surgical management for infants with HLHS. The Norwood operation has became a milestone in the effective palliation for neonates born with HLHS. Today, the Norwood procedure is the first step of a three-stage heart surgery aimed at creating a new circulatory pathway (i.e., the Fontan pathway).

Biofabrication in Congenital Cardiac Surgery: A Plea from the Operating Theatre, Promise from Science

Despite significant advances in numerous fields of biofabrication, clinical application of biomaterials combined with bioactive molecules and/or cells largely remains a promise in an individualized patient settings. Three-dimensional (3D) printing and bioprinting evolved as promising techniques used for tissue-engineering, so that several kinds of tissue can now be printed in layers or as defined structures for replacement and/or reconstruction in regenerative medicine and surgery. Besides technological, practical, ethical and legal challenges to solve, there is also a gap between the research labs and the patients' bedside. Congenital and pediatric cardiac surgery mostly deal with reconstructive patient-scenarios when defects are closed, various segments of the heart are connected, valves are implanted. Currently available biomaterials lack the potential of growth and conduits, valves derange over time surrendering patients to reoperations. Availability of viable, growing biomaterials could cancel reoperations that could entail significant public health benefit and improved quality-of-life. Congenital cardiac surgery is uniquely suited for closing the gap in translational research, rapid application of new techniques, and collaboration between interdisciplinary teams. This article provides a succinct review of the state-of-the art clinical practice and biofabrication strategies used in congenital and pediatric cardiac surgery, and highlights the need and avenues for translational research and collaboration.

Global Leadership in Paediatric and Congenital Cardiac Care: "Following the 'Golden Rule' in multicentre collaborations - an interview with Jane W. Newburger, MD"

Dr. Jane Newburger is the focus of our first in a planned series of interviews in Cardiology in the Young entitled, "Global Leadership in Paediatric and Congenital Cardiac Care". Dr. Newburger was born in Manhattan, New York, United States of America. She was raised in the Bronx for her first six years of life, at which point her family moved to Yonkers, New York, where she spent the rest of her childhood. She then attended Bryn Mawr College where she majored in psychology. Dr. Newburger subsequently attended Harvard Medical School, graduating in 1974. She did her internship and residency in paediatrics at Boston Children's Hospital in 1974-1976, followed by her fellowship at Boston Children's Hospital in 1976-1979. She received her Masters in Public Health at the Harvard School of Public Health in 1980.Dr. Newburger has spent her entire career as a paediatric cardiologist at Boston Children's Hospital and Harvard Medical School, where she was appointed a Professor of Pediatrics in 1999 and has held the position as Commonwealth Professor of Pediatrics since 2008. She has established herself as a leading clinical scientist within the field of paediatric cardiology, with expertise in leadership of multicentre and multidisciplinary research, including the building of collaborative groups. She has been continuously funded by the National Institute of Health since 1982, and amongst other areas has led the field in the areas of neurodevelopmental outcomes in congenital heart disease, improved methods of vital organ support, and management of Kawasaki disease. This article presents our interview with Dr. Newburger, an interview that covers her path towards becoming a clinical scientist, her interests spanning four decades of hard work, and her strategies to design and lead successful multicentre studies.

Epidemiology and Outcomes of Acute Decompensated Heart Failure in Children

BACKGROUND

Acute decompensated heart failure (ADHF) is a highly morbid condition among adults. Little is known about outcomes in children with ADHF. We analyzed the Pediatric Cardiac Critical Care Consortium registry to determine the epidemiology, contemporary treatments, and predictors of mortality in critically ill children with ADHF.

METHODS

Cardiac intensive care unit (CICU) patients ≤18 years of age meeting Pediatric Cardiac Critical Care Consortium criteria for ADHF were included. ADHF was defined as systolic or diastolic dysfunction requiring continuous vasoactive or diuretic infusion, respiratory support, or mechanical circulatory support. Demographics, diagnosis, therapies, complications, and mortality are described for the cohort. Predictors of CICU mortality were identified using logistic regression.

RESULTS

Among 26 294 consecutive admissions (23 centers), 1494 (6%) met criteria for analysis. Median age was 0.93 years (interquartile range, 0.1-9.3 years). Patients with congenital heart disease (CHD) comprised 57% of the cohort. Common therapies included the following: vasoactive infusions (88%), central venous catheters (86%), mechanical ventilation (59%), and high flow nasal cannula (46%). Common complications were arrhythmias (19%), cardiac arrest (10%), sepsis (7%), and acute renal failure requiring dialysis (3%). Median length of CICU stay was 7.9 days (interquartile range, 3-18 days) and the CICU readmission rate was 22%. Overall, CICU mortality was 15% although higher for patients with CHD versus non-CHD (19% versus 11%; P<0.001). Independent risk factors associated with CICU mortality included age <30 days, CHD, vasoactive infusions, ventricular tachycardia, mechanical ventilation, sepsis, pulmonary hypertension, extracorporeal membrane oxygenation, and cardiac arrest.

CONCLUSIONS

ADHF in children is characterized by comorbidities, high mortality rates, and frequent readmission, especially among patients with CHD. Opportunities exist to determine best practices around appropriate use of mechanical support, cardiac arrest prevention, and optimal heart transplantation candidacy to improve outcomes for these patients.

Ventricular Assist Device Therapy and Fontan: A Story of Supply and Demand

The last 10 years have seen an increase in the number of Fontan patients with heart failure. There has been a coincident rapid evolution in the field of pediatric and congenital heart disease ventricular assist device therapy. Herein, we describe the existing body of literature regarding the use of ventricular assist device therapy in the Fontan circulation as well as the current approach to clinical decision-making and device implantation within the field.

Impact of Initial Shunt Type on Echocardiographic Indices in Children After Single Right Ventricle Palliations

Background Heart size and function in children with single right ventricle (RV) anomalies may be influenced by shunt type at the Norwood procedure. We sought to identify shunt-related differences during early childhood after staged surgical palliations using echocardiography. Methods We compared echocardiographic indices of RV, neoaortic, and tricuspid valve size and function at 14 months, pre-Fontan, and 6 years in 241 subjects randomized to a Norwood procedure using either the modified Blalock-Taussig shunt or RV-to-pulmonary-artery shunt. Results At 6 years, the shunt groups did not differ significantly in any measure except for increased indexed neoaortic area in the modified Blalock-Taussig shunt. RV ejection fraction improved between pre-Fontan and 6 years in the RV-to-pulmonary artery shunt group but was stable in the modified Blalock-Taussig shunt group. For the entire cohort, RV diastolic and systolic size and functional indices were improved at 6 years compared with earlier measurements, and indexed tricuspid and neoaortic annular area decreased from 14 months to 6 years. The prevalence of ≥moderate tricuspid and neoaortic regurgitation was uncommon and did not vary by group or time period. Diminished RV ejection fraction at the 14-month study was predictive of late death/transplant; the hazard of late death/transplant when RV ejection fraction was <40% was tripled (hazard ratio, 3.18; 95% CI, 1.41-7.17). Conclusions By 6 years after staged palliation, shunt type has not impacted RV size and function, and RV and valvar size and function show beneficial remodeling. Poor RV systolic function at 14 months predicts worse late survival independent of the initial shunt type. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT00115934.

[Current surgical options and outcomes for newborns with hypoplastic left heart syndrome]

Since the first successful palliation was performed by Norwood et al. in 1983, there have been substantial changes in diagnosis, management, and outcomes of hypoplastic left heart syndrome, Survival for stage 1 palliation has increased to 90% in many centres, with patients potentially surviving into adulthood. However, the associated morbidity and mortality remain substantial. Although the principles of staged surgical palliation of hypoplastic left heart syndrome are well established, there is significant variability in surgical procedure and management between centres, and several controversial aspects remain unresolved. In this review, we summarize the current surgical and management options for newborns with hypoplastic left heart syndrome and their outcomes.

Hypoplastic left heart syndrome: From bedside to bench and back

Hypoplastic Left Heart Syndrome (HLHS) is a complex Congenital Heart Disease (CHD) that was almost universally fatal until the advent of the Norwood operation in 1981. Children with HLHS who largely succumbed to the disease within the first year of life, are now surviving to adulthood. However, this survival is associated with multiple comorbidities and HLHS infants have a higher mortality rate as compared to other non-HLHS single ventricle patients. In this review we (a) discuss current clinical challenges associated in the care of HLHS patients, (b) explore the use of systems biology in understanding the molecular framework of this disease, (c) evaluate induced pluripotent stem cells as a translational model to understand molecular mechanisms and manipulate them to improve outcomes, and (d) investigate cell therapy, gene therapy, and tissue engineering as a potential tool to regenerate hypoplastic cardiac structures and improve outcomes.

Postoperative heart failure after stage 1 palliative surgery for single ventricle cardiac disease

Outcomes for patients with single ventricle congenital heart disease (SV-CHD) continue to improve over time. However, the prognosis for patients who develop heart failure immediately after surgery is poorly understood. We conducted a single-center, retrospective cohort study of patients with SV-CHD, who suffered postoperative heart failure. Of 1038 cardiac surgeries performed on 621 SV-CHD patients between 2004 and 2010, 125 patients met inclusion criteria, including non-septatable anatomy, stage 1 surgery, and verified low cardiac output or heart failure state per STS definition. Overall survival was 73.2% at 2 months, 64.9% at 1 year, 60.5% at 2 years, and 54.6% at 4 years. Inotrope dependence beyond 7 days post-op yielded 45% 2-year survival versus 68% for those who weaned from inotropes within 7 days (p = 0.02). Atrioventricular valve regurgitation (AVVR) influenced survival, and patients who developed renal failure or required ECMO fared poorly, even when they survived their hospitalization. Patients with postoperative heart failure and low cardiac output syndrome constitute a high-risk population beyond the term of the initial hospitalization and have an overall mid-term survival of 55% at 4 years. Wean from inotropic therapy is not completely reassuring in this population, as they have ongoing elevated risk of cardiac failure and death in the medium term. Ventricular dysfunction, AVVR, renal failure, and need for ECMO are all important prognostic factors for mid-term mortality. Inotrope dependence for > 7 days has important implications reaching beyond the hospitalization.

Outcomes and factors associated with early mortality in pediatric and neonatal patients requiring extracorporeal membrane oxygenation for heart and lung failure

BACKGROUND

Mortality and morbidity after surgical repair for complex congenital heart defects and severe cardiopulmonary failure on extracorporeal membrane oxygenation (ECMO) support remain high despite significant advances in medical management and technological improvements. We report on outcomes and factors after using ECMO in our surgical pediatric population including short- and long-term survival.

METHODS

A total of 45 neonatal and pediatric patients were identified who needed ECMO in our department between January 2008 and December 2016. In 41 cases (91%) a vaECMO (ECLS) was implemented, whereas 4 patients (9%) received vvECMO treatment for respiratory failure. In 33 cases vaECMO was implanted following cardiac surgery for congenital heart disease (CHD), whereas in 8 patients ECMO was utilized by means of extracorporeal cardiopulmonary resuscitation (eCPR) following refractory cardiac arrest. The primary endpoint of the present study was survival to discharge and long-term survival free from neurological impairments. Univariate and bivariate analysis was performed to address predictors for outcome. Kaplan-Meier survival analysis was used to address mid- and long-term survival.

RESULTS

Median [IQR] duration of ECMO support was 3 [2, 5] days (range, 1-17 days). Median age at ECMO implantation was 128 [14, 1,813] days, median weight of patients was 5.4 [3.3, 12] kg. Totally 10 patients included in this study were diagnosed with concomitant genetic conditions. A total of 20 (44%) patients were successfully weaned off ECMO (survived >24 h after ECMO explantation), whereas 15 (33%) of them survived to discharge. Single ventricle (SV) repair was performed in 14, biventricular repair in 19 patients. Neonates (<30 days of age), female patients, patients with genetic conditions, SV repair patients, and eCPR patient cohort showed lower odds of survival on ECMO. Failed myocardial recovery (P=0.001), profound circulatory failure despite a high dose of catecholamines (P<0.001), neurological impairment pre-ECMO and post-ECMO (P=0.04 and P<0.001, respectively), and severe pulmonary failure despite high respiratory pressure settings were most common mortality reasons.

CONCLUSIONS

ECMO provides efficient therapy opportunities for life-threatening conditions. Nevertheless, neonates and pediatric patients who underwent ECMO were at high risk for cerebrovascular events and poor survival. Appropriate patient selection using predictors of outcome reducing complications might improve outcomes of this patient cohort.

Serial Strain Analysis Identifies Hypoplastic Left Heart Syndrome Infants at Risk for Cardiac Morbidity and Mortality: A Pilot Study

BACKGROUND

Validated, objective measures of right ventricular (RV) function assessment in hypoplastic left heart syndrome (HLHS) are needed. In other populations, speckle-tracking echocardiography-derived strain is a sensitive measure that outperforms conventional parameters of RV function. We hypothesized that speckle-tracking echocardiography-derived measures of RV function would be worse in patients with HLHS who have a poor cardiac outcome.

METHODS

Prospective serial echocardiography was performed in 35 infants with HLHS during the first 6 months of life. Patients not undergoing staged palliation or with other variants of single RV were excluded. Traditional RV measurements and strain analysis were performed from standard apical and basal views. The primary outcome of cardiac death, heart transplantation, or persistent ≥ moderate RV dysfunction was examined using Cox regression analysis, and receiver operating characteristic curve analyses were performed to derive cutoff values.

RESULTS

At median follow-up of 10.9 months (interquartile range 5.6, 15.2), eight patients reached the outcome and demonstrated worse RV strain measures compared with those without the outcome. A post-Norwood global longitudinal strain (GLS) of > -16% (area under the curve [AUC] = 0.76; P = .04) and pre-Glenn GLS > -13% (AUC, 0.98; P ≤ .01) were highly sensitive and specific for poor outcome. Other thresholds included post-Norwood GLS rate (GLSr) > -1.15 %/s (AUC, 0.78; P = .03), pre-Glenn GLSr = -0.85%/sec (AUC, 0.89; P < .01), post-Glenn circumferential strain rate > -0.85%/sec (AUC, 0.92; P < .01), and GLSr > -0.85%/sec (AUC, 0.84; P = .02).

CONCLUSIONS

Strain analysis may help identify at-risk HLHS infants. In this pilot study, interstage strain indices were worse in infants with HLHS who had a poor cardiac outcome.

The Case for Cardiac Xenotransplantation in Neonates: Is Now the Time to Reconsider Xenotransplantation for Hypoplastic Left Heart Syndrome?

Neonatal cardiac transplantation for hypoplastic left heart syndrome (HLHS) is associated with excellent long-term survival compared to older recipients. However, heart transplantation for neonates is greatly limited by the critical shortage of donor hearts, and by the associated mortality of the long pre-transplant waiting period. This led to the development of staged surgical palliation as the first-line surgical therapy for HLHS. Recent advances in genetic engineering and xenotransplantation have provided the potential to replicate the excellent results of neonatal cardiac allotransplantation while eliminating wait-list-associated mortality through genetically modified pig-to-human neonatal cardiac xenotransplantation. The elimination of the major pig antigens in addition to the immature B-cell response in neonates allows for the potential to induce B-cell tolerance. Additionally, the relatively mature neonatal T-cell response could be reduced by thymectomy at the time of operation combined with donor-specific pig thymus transplantation to "reprogram" the host's T-cells to recognize the xenograft as host tissue. In light of the recent significantly increased graft survival of genetically-engineered pig-to-baboon cardiac xenotransplantation, we propose that now is the time to consider devoting research to advance the potential clinical application of cardiac xenotransplantation as a treatment option for patients with HLHS. Employing cardiac xenotransplantation could revolutionize therapy for complex congenital heart defects and open a new chapter in the field of pediatric cardiac transplantation.