Comparison of shunt types in the Norwood procedure for single-ventricle lesions

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.

Association between weight-for-length percentile and ICU length of stay in patients with a single ventricle undergoing bidirectional Glenn repair: A retrospective cohort study

BACKGROUND

Poor weight gain has been identified as an independent risk factor for increased surgical morbidity and mortality for patients with single-ventricle physiology undergoing staged surgical palliation. Conversely, excessive weight gain has also emerged as an independent risk factor predicting increased morbidity and mortality in a single-center study. Given this novel single-center concept, we investigated the impact of excessive weight on patients with single-ventricle physiology undergoing bidirectional Glenn palliation in a multicenter study model.

METHODS

Patients from the Pediatric Heart Network Single Ventricle Reconstruction Trial (n = 387) were analyzed in a retrospective cohort study examining the independent effect of weight percentile on intensive care unit (ICU) length of stay (LOS) and ventilator days. Locally estimated scatterplot smoothing (LOESS) regression was used to plot weight-for-length (WFL) percentiles by ICU LOS and ventilator days. Unadjusted and adjusted ordinal regression was used to model ICU LOS and ventilator days.

RESULTS

Scatterplots and LOESS regression curves demonstrated increasing ICU LOS and ventilator days for increasing WFL percentiles. Unadjusted ordinal regression analysis of ICU LOS demonstrated a trend of increasing ICU LOS for increasing WFL percentiles that was not statistically significant (P = 0.11). A similar trend was demonstrated in adjusted ordinal regression that was not statistically significant (P = 0.48). Unadjusted and adjusted ordinal regression analysis of ventilator days did not reach statistical significance (P = 0.07).

CONCLUSION

Excessive weight gain has a clinically relevant but not statistically significant association with increased ICU LOS and ventilator days for those patients in the >90th WFL percentile for age.

Valved Sano conduit improves immediate outcomes following Norwood operation compared with nonvalved Sano conduit

OBJECTIVE

Use of a valved Sano during the Norwood procedure has been reported previously, but its impact on clinical outcomes needs to be further elucidated. We assessed the impact of the valved Sano compared with the nonvalved Sano after the Norwood procedure in patients with hypoplastic left heart syndrome.

METHODS

We retrospectively reviewed 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a valved Sano conduit using a femoral venous homograft and 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a nonvalved Sano conduit between 2013 and 2022. Primary outcomes were end-organ function postoperatively and ventricular function over time. Secondary outcomes were cardiac events, all-cause mortality, and Sano and pulmonary artery reinterventions at discharge, interstage, and pre-Glenn time points.

RESULTS

Postoperatively, the valved Sano group had significantly lower peak and postoperative day 1 lactate levels (P = .033 and P = .025, respectively), shorter time to diuresis (P = .043), and shorter time to enteral feeds (P = .038). The valved Sano group had significantly fewer pulmonary artery reinterventions until the Glenn operation (n = 1 vs 8; P = .044). The valved Sano group showed significant improvement in ventricular function from the immediate postoperative period to discharge (P < .001). From preoperative to pre-Glenn time points, analysis of ventricular function showed sustained ventricular function within the valved Sano group, but a significant reduction of ventricular function in the nonvalved Sano group (P = .003). Pre-Glenn echocardiograms showed competent conduit valves in two-thirds of the valved Sano group (n = 16; 67%).

CONCLUSIONS

The valved Sano is associated with improved multi-organ recovery postoperatively, better ventricular function recovery, and fewer pulmonary artery reinterventions until the Glenn procedure.

Outcome after extracorporeal membrane oxygenation therapy in Norwood patients before the bidirectional Glenn operation

OBJECTIVES

Patients after the Norwood procedure are prone to postoperative instability. Extracorporeal membrane oxygenation (ECMO) can help to overcome short-term organ failure. This retrospective single-centre study examines ECMO weaning, hospital discharge and long-term survival after ECMO therapy between Norwood and bidirectional Glenn palliation as well as risk factors for mortality.

METHODS

In our institution, over 450 Norwood procedures have been performed. Since the introduction of ECMO therapy, 306 Norwood operations took place between 2007 and 2022, involving ECMO in 59 cases before bidirectional Glenn. In 48.3% of cases, ECMO was initiated intraoperatively post-Norwood. Patient outcomes were tracked and mortality risk factors were analysed using uni- and multivariable testing.

RESULTS

ECMO therapy after Norwood (median duration: 5 days; range 0-17 days) saw 31.0% installed under CPR. Weaning was achieved in 46 children (78.0%), with 55.9% discharged home after a median of 45 (36-66) days. Late death occurred in 3 patients after 27, 234 and 1541 days. Currently, 30 children are in a median 4.8 year (3.4-7.7) follow-up. At the time of inquiry, 1 patient awaits bidirectional Glenn, 6 are at stage II palliation, Fontan was completed in 22 and 1 was lost to follow-up post-Norwood. Risk factor analysis revealed dialysis (P < 0.001), cerebral lesions (P = 0.026), longer ECMO duration (P = 0.002), cardiac indication and lower body weight (P = 0.038) as mortality-increasing factors. The 10-year mortality probability after ECMO therapy was 48.5% (95% CI 36.5-62.9%).

CONCLUSIONS

ECMO therapy in critically ill patients after the Norwood operation may significantly improve survival of a patient cohort otherwise forfeited and give the opportunity for successful future-stage operations.

Precision in Norwood Shunt Sizing: Single Ventricle Reconstruction Trial Public Dataset Analysis

BACKGROUND

Morbidity and mortality after the Norwood procedure remains high. Shunt size selection is not standardized and the impact of shunt size on outcomes is poorly understood. The Single Ventricle Reconstruction trial randomized infants to modified Blalock-Taussig-Thomas shunt (MBTTS) or right ventricle-to-pulmonary artery shunt at the Norwood procedure. We assessed shunt size distribution and its association with postoperative outcomes.

METHODS

We included 544 patients, excluding 5 with ambiguous shunt crossover data. Normalized shunt diameter 1 and 2 were calculated as shunt diameter divided by patient's weight and body surface area, respectively. The primary outcome was 30-day mortality after Norwood. Secondary outcomes were intensive care and total length of stay, and survival to Glenn procedure. Logistic and ordinal regression models evaluated the association of normalized shunt diameter with outcomes.

RESULTS

Thirty-day mortality after Norwood was 11.4% (n = 62), survival to Glenn procedure was 72.6% (n = 395), median length of stay was 14.0 (interquartile range, 9.0-27.7) days and 24.0 (interquartile range, 16.0-41.0) days in the intensive care and total, respectively. Normalized shunt diameters exhibited variation in both shunt types but were not associated with 30-day mortality. Right ventricle-to-pulmonary artery shunt size was not associated with secondary outcomes. However, a MBTTS diameter ≥1.5 mm/kg predicted longer Norwood (odds ratio, 4.89; 95% CI, 1.41-16.90) and intensive care (odds ratio, 4.11; 95% CI, 1.25-13.49]) duration.

CONCLUSIONS

Shunt size selection was variable. Right ventricle-to-pulmonary artery shunt had a wider size range seen with favorable outcomes compared with MBTTS. A MBTTS either too large or too small is associated with worse postoperative outcomes. Refining shunt sizing practices can improve surgical outcomes after the Norwood procedure.

Surgical Modulation of Pulmonary Artery Shear Stress: A Patient-Specific CFD Analysis of the Norwood Procedure

PURPOSR

This study created 3D CFD models of the Norwood procedure for hypoplastic left heart syndrome (HLHS) using standard angiography and echocardiogram data to investigate the impact of shunt characteristics on pulmonary artery (PA) hemodynamics. Leveraging routine clinical data offers advantages such as availability and cost-effectiveness without subjecting patients to additional invasive procedures.

METHODS

Patient-specific geometries of the intrathoracic arteries of two Norwood patients were generated from biplane cineangiograms. "Virtual surgery" was then performed to simulate the hemodynamics of alternative PA shunt configurations, including shunt type (modified Blalock-Thomas-Taussig shunt (mBTTS) vs. right ventricle-to-pulmonary artery shunt (RVPAS)), shunt diameter, and pulmonary artery anastomosis angle. Left-right pulmonary flow differential, Qp/Qs, time-averaged wall shear stress (TAWSS), and oscillatory shear index (OSI) were evaluated.

RESULTS

There was strong agreement between clinically measured data and CFD model output throughout the patient-specific models. Geometries with a RVPAS tended toward more balanced left-right pulmonary flow, lower Qp/Qs, and greater TAWSS and OSI than models with a mBTTS. For both shunt types, larger shunts resulted in a higher Qp/Qs and higher TAWSS, with minimal effect on OSI. Low TAWSS areas correlated with regions of low flow and changing the PA-shunt anastomosis angle to face toward low TAWSS regions increased TAWSS.

CONCLUSION

Excellent correlation between clinically measured and CFD model data shows that 3D CFD models of HLHS Norwood can be developed using standard angiography and echocardiographic data. The CFD analysis also revealed consistent changes in PA TAWSS, flow differential, and OSI as a function of shunt characteristics.

Hybrid Interventions in Congenital Heart Disease: A Review of Current Practice and Rationale for Use

BACKGROUND

Hybrid interventions have become a common option in the management for a variety of patients with congenital heart disease. In this review, we discuss the data that have driven decision making about hybrid interventions to date.

METHODS

The existing literature on various hybrid approaches was reviewed and summarized. In addition, the key tenants to creating a successful hybrid program within a congenital heart center are elucidated.

RESULTS

Hybrid strategies for single-ventricle patients, pulmonary atresia with intact ventricular septum, branch pulmonary artery stenosis, and muscular ventricular septal defect closure have important benefits and limitations compared with traditional approaches.

CONCLUSION

A growing body of evidence supports the use of hybrid interventions in congenital heart disease. But important questions remain regarding improved survival and other long-term outcomes, such as neurocognition, that might impact widespread adoption as a primary treatment strategy.

Myocardial protection in paediatric cardiac surgery: building an evidence-based strategy

Cardioplegia is fundamental to the surgical repair of congenital heart defects by protecting the heart against ischaemia/reperfusion injury, characterised by low cardiac output and troponin release in the early postoperative period. The immature myocardium exhibits structural, physiological and metabolic differences from the adult heart, with a greater sensitivity to calcium overload-mediated injury during reperfusion. Del Nido cardioplegia was designed specifically to protect the immature heart, is widely used in North America and may provide better myocardial protection in children; however, it has not been commercially available in the UK, where most centres use St Thomas' blood cardioplegia. There are no phase 3 clinical trials in children to support one solution over another and this lack of evidence, combined with variations in practice, suggests the presence of clinical equipoise. The best cardioplegia solution for use in children, and the impact of age and other clinical factors remain unknown. In this Hunterian lecture, I propose an evidence-based strategy to improve myocardial protection during cardiac surgery in children through: (1) conducting multicentre clinical trials of established techniques; (2) improving our knowledge of ischaemia/reperfusion injury in the setting of cardioplegic arrest; (3) applying this to drive innovation, moving beyond current cardioplegia solutions; (4) empowering personalised medicine, through combining clinical and genomic data, including ethnic diversity; and (5) understanding the impact of cardioplegic arrest on the late outcomes that matter to patients and their families.

Acute kidney injury in hypoplastic left heart syndrome patients following the comprehensive stage two palliation

BACKGROUND

An alternative surgical approach for hypoplastic left heart syndrome is the Hybrid pathway, which delays the risk of acute kidney injury outside of the newborn period. We sought to determine the incidence, and associated morbidity, of acute kidney injury after the comprehensive stage 2 and the cumulative incidence after the first two operations in the Hybrid pathway.

DESIGN

A single centre, retrospective study was conducted of hypoplastic left heart patients completing the second-stage palliation in the Hybrid pathway from 2009 to 2018. Acute kidney injury was defined utilising Kidney Diseases Improving Global Outcomes criteria. Perioperative and post-operative characteristics were analysed.

RESULTS

Sixty-one patients were included in the study cohort. The incidence of acute kidney injury was 63.9%, with 36.1% developing severe injury. Cumulatively after the Hybrid Stage 1 and comprehensive stage 2 procedures, 69% developed acute kidney injury with 36% developing severe injury. The presence of post-operative acute kidney injury was not associated with an increase in 30-day mortality (acute kidney injury 7.7% versus none 9.1%; p = > 0.9). There was a significantly longer median duration of intubation among those with acute kidney injury (acute kidney injury 32 (8, 155) hours vs. no injury 9 (0, 94) hours; p = 0.018).

CONCLUSIONS

Acute kidney injury after the comprehensive stage two procedure is common and accounts for most of the kidney injury in the first two operations of the Hybrid pathway. No difference in mortality was detected between those with acute kidney injury and those without, although there may be an increase in morbidity.

Population Pharmacokinetics of Caffeine in Neonates with Congenital Heart Disease and Associations with Acute Kidney Injury

Cardiac surgery-associated acute kidney injury (CS-AKI) occurs in approximately 65% of neonates undergoing cardiac surgery on cardiopulmonary bypass and contributes to morbidity and mortality. Caffeine may reduce CS-AKI by counteracting adenosine receptor upregulation after bypass, but pharmacokinetics (PK) in this population are unknown. The goal of our analysis is to address knowledge gaps in age-, disease-, and bypass-related effects on caffeine disposition and explore preliminary associations between caffeine exposure and CS-AKI using population PK modeling techniques and an opportunistic, electronic health record-integrated trial design. We prospectively enrolled neonates receiving preoperative caffeine per standard of care and collected PK samples. We retrospectively identified neonates without caffeine exposure undergoing surgery on bypass as a control cohort. We followed US Food and Drug Administration guidance for population PK model development using NONMEM. Effects of clinical covariates on PK parameters were evaluated. We simulated perioperative exposures and used multivariable logistic regression to evaluate the association between caffeine exposure and CS-AKI. Twenty-seven neonates were included in model development. A 1-compartment model with bypass time as a covariate on clearance and volume of distribution best fit the data. Twenty-three neonates with caffeine exposure and 109 controls were included in the exposure-response analysis. Over half of neonates developed CS-AKI. On multivariable analysis, there were no significant differences between CS-AKI with and without caffeine exposure. Neonates with single-ventricle heart disease without CS-AKI had consistently higher simulated caffeine exposures. Our results highlight areas for further study to better understand disease- and bypass-specific effects on drug disposition and identify populations where caffeine may be beneficial.

Treatment of hypoplastic left heart syndrome: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

This meta-analysis aimed to consolidate existing data from randomised controlled trials on hypoplastic left heart syndrome.

METHODS

Hypoplastic left heart syndrome specific randomised controlled trials published between January 2005 and September 2021 in MEDLINE, EMBASE, and Cochrane databases were included. Regardless of clinical outcomes, we included all randomised controlled trials about hypoplastic left heart syndrome and categorised them according to their results. Two reviewers independently assessed for eligibility, relevance, and data extraction. The primary outcome was mortality after Norwood surgery. Study quality and heterogeneity were assessed. A random-effects model was used for analysis.

RESULTS

Of the 33 included randomised controlled trials, 21 compared right ventricle-to-pulmonary artery shunt and modified Blalock-Taussig-Thomas shunt during the Norwood procedure, and 12 regarded medication, surgical strategy, cardiopulmonary bypass tactics, and ICU management. Survival rates up to 1 year were superior in the right ventricle-to-pulmonary artery shunt group; this difference began to disappear at 3 years and remained unchanged until 6 years. The right ventricle-to-pulmonary artery shunt group had a significantly higher reintervention rate from the interstage to the 6-year follow-up period. Right ventricular function was better in the modified Blalock-Taussig-Thomas shunt group 1-3 years after the Norwood procedure, but its superiority diminished in the 6-year follow-up. Randomised controlled trials regarding medical treatment, surgical strategy during cardiopulmonary bypass, and ICU management yielded insignificant results.

CONCLUSIONS

Although right ventricle-to-pulmonary artery shunt appeared to be superior in the early period, the two shunts applied during the Norwood procedure demonstrated comparable long-term prognosis despite high reintervention rates in right ventricle-to-pulmonary artery shunt due to pulmonary artery stenosis. For medical/perioperative management of hypoplastic left heart syndrome, further randomised controlled trials are needed to deliver specific evidence-based recommendations.

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.

Longitudinal analysis of systemic ventricular function and atrioventricular valve function after the Norwood procedure

OBJECTIVES

To evaluate longitudinal systemic ventricular function and atrioventricular valve regurgitation in patients after the neonatal Norwood procedure.

METHODS

Serial postoperative echocardiographic images before Fontan completion were assessed in neonates who underwent the Norwood procedure between 2001 and 2020. Ventricular function and atrioventricular valve regurgitation were compared between patients with modified Blalock-Taussig shunt and right ventricle to pulmonary artery conduit.

RESULTS

A total of 335 patients were identified including 273 hypoplastic left heart syndrome and 62 of its variants. Median age at Norwood was 8 (7-12) days. Modified Blalock-Taussig shunt was performed in 171 patients and the right ventricle to pulmonary artery conduit in 164 patients. Longitudinal ventricular function and atrioventricular valve regurgitation were evaluated using a total of 4352 echocardiograms. After the Norwood procedure, ventricular function was initially worse (1-30 days) but thereafter better (30 days to stage II) in the right ventricle to pulmonary artery conduit group (P < 0.001). After stage II, the ventricular function was inferior in the right ventricle to the pulmonary artery conduit group (P < 0.001). Atrioventricular valve regurgitation between the Norwood procedure and stage II was more frequent in the modified Blalock-Taussig shunt group (P < 0.001). After stage II, there was no significant difference in atrioventricular valve regurgitation between the groups (P = 0.171).

CONCLUSIONS

The effect of shunt type on haemodynamics after the Norwood procedure seems to vary according to the stage of palliation. After the Norwood, the modified Blalock-Taussig shunt is associated with poorer ventricular function and worse atrioventricular valve regurgitation compared to right ventricle to pulmonary artery conduit. Whereas, after stage II, modified Blalock-Taussig shunt is associated with better ventricular function and comparable atrioventricular valve regurgitation, compared to the right ventricle to pulmonary artery conduit.

Using machine learning to predict five-year transplant-free survival among infants with hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a congenital malformation commonly treated with palliative surgery and is associated with significant morbidity and mortality. Risk stratification models have often relied upon traditional survival analyses or outcomes data failing to extend beyond infancy. Individualized prediction of transplant-free survival (TFS) employing machine learning (ML) based analyses of outcomes beyond infancy may provide further valuable insight for families and healthcare providers along the course of a staged palliation. Data from both the Pediatric Heart Network (PHN) Single Ventricle Reconstruction (SVR) trial and Extension study (SVR II), which extended cohort follow up for five years was used to develop ML-driven models predicting TFS. Models incrementally incorporated features corresponding to successive phases of care, from pre-Stage 1 palliation (S1P) through the stage 2 palliation (S2P) hospitalization. Models trained with features from Pre-S1P, S1P operation, and S1P hospitalization all demonstrated time-dependent area under the curves (td-AUC) beyond 0.70 through 5 years following S1P, with a model incorporating features through S1P hospitalization demonstrating particularly robust performance (td-AUC 0.838 (95% CI 0.836-0.840)). Machine learning may offer a clinically useful alternative means of providing individualized survival probability predictions, years following the staged surgical palliation of hypoplastic left heart syndrome.

From Surgical to Total Transcatheter Stage I Palliation: Exploring Evidence and Perspectives

Neonates with single ventricle physiology and ductal-dependent systemic circulation, such as those with hypoplastic left heart syndrome, undergo palliation in the first days of life. Over the past decades, variations on the traditional Stage 1 palliation, also known as Norwood operation, have emerged. These include the hybrid palliation and the total transcatheter approach. Here, we review the current evidence and data on different Stage 1 approaches, with a focus on their advantages, challenges, and future perspectives. Overall, although controversy remains regarding the superiority or inferiority of one approach to another, outcomes after the Norwood and the hybrid palliation have improved over time. However, both procedures still represent high-risk approaches that entail exposure to sternotomy, surgery, and potential cardiopulmonary bypass. The total transcatheter Stage 1 palliation spares patients the surgical and cardiopulmonary bypass insults and has proven to be an effective strategy to bridge even high-risk infants to a later palliative surgery, complete repair, or transplant. As the most recently proposed approach, data are still limited but promising. Future studies will be needed to better define the advantages, challenges, outcomes, and overall potential of this novel approach.

Association Between Remote Monitoring and Interstage Morbidity and Death in Patients With Single-Ventricle Heart Disease Across Socioeconomic Groups

BACKGROUND

Despite improvements in survival over time, the mortality rate for infants with single-ventricle heart disease remains high. Infants of low socioeconomic status (SES) are particularly vulnerable. We sought to determine whether use of a novel remote monitoring program, the Cardiac High Acuity Monitoring Program, mitigates differences in outcomes by SES.

METHODS AND RESULTS

Within the Cardiac High Acuity Monitoring Program, we identified 610 infants across 11 centers from 2014 to 2021. All enrolled families had access to a mobile application allowing for near-instantaneous transfer of patient information to the care team. Patients were divided into SES tertiles on the basis of 6 variables relating to SES. Hierarchical logistic regression, adjusted for potential confounding characteristics, was used to determine the association between SES and death or transplant listing during the interstage period. Of 610 infants, 39 (6.4%) died or were listed for transplant. In unadjusted analysis, the rate of reaching the primary outcome between SES tertiles was similar (P=0.24). Even after multivariable adjustment, the odds of death or transplant listing were no different for those in the middle (odds ratio, 1.7 [95% CI, 0.73-3.94) or highest (odds ratio, 0.997 [95% CI, 0.30, 3.36]) SES tertile compared with patients in the lowest (overall P value 0.4).

CONCLUSIONS

In a large multicenter cohort of infants with single-ventricle heart disease enrolled in a digital remote monitoring program during the interstage period, we found no difference in outcomes based on SES. Our study suggests that this novel technology could help mitigate differences in outcomes for this fragile population of patients.

Bilateral pulmonary artery banding in higher risk neonates with hypoplastic left heart syndrome

Objectives

Limited data on performing bilateral pulmonary artery banding (BPAB) before stage 1 Norwood procedure suggest that some patients may benefit through the postponement of the major cardiopulmonary bypass procedure. The objective of this study was to evaluate the effectiveness of BPAB in the surgical management of high-risk patients with hypoplastic left heart syndrome (HLHS).

Methods

A retrospective review of all high-risk neonates with HLHS who underwent BPAB at our institution was performed. No patients, including those with intact or highly restrictive atrial septum (IAS), were excluded.

Results

Between October 2015 and April 2021, 49 neonates with HLHS (including 6 with IAS) underwent BPAB, 40 of whom progressed to the Norwood procedure. Risk factors for not progressing to the Norwood procedure after BPAP include low birth weight (P = .043), the presence of multiple extracardiac anomalies (P = .005), and the presence of genetic disorders (P = .028). Operative mortality was 7.5% (3/40). IAS was associated with operative mortality (P = .022).

Conclusions

The strategy of BPAB prestage 1 Norwood procedure was successful in identifying at-risk patients and improving Norwood survival. Although not all patients will need this hybrid approach, a significant number can be expected to benefit from this tactic. These results support the need for a substantial hybrid strategy, in addition to a primary stage 1 Norwood surgical strategy, in the management of HLHS.

Pre-Glenn aorto-pulmonary collaterals in single-ventricle patients

BACKGROUND

In single-ventricle patients undergoing staged-bidirectional Glenn, 36-59% have aorto-pulmonary collateral flow, but risk factors and clinical outcomes are unknown. We hypothesise that shunt type and catheter haemodynamics may predict pre-bidirectional Glenn aorto-pulmonary collateral burden, which may predict death/transplantation, pulmonary artery or aorto-pulmonary collateral intervention.

METHODS

Retrospective cohort study of patients undergoing a Norwood procedure for single-ventricle anatomy. Covariates included clinical and haemodynamic characteristics up to/including pre-bidirectional Glenn catheterisation and aorto-pulmonary collateral burden at pre-bidirectional Glenn catheterisation. Multivariable models used to evaluate relationships between risk factors and outcomes.

RESULTS

From January 2011 to March 2016, 104 patients underwent Norwood intervention. Male sex (odds ratio 3.36, 95% confidence interval 1.17-11.4), age at pre-bidirectional Glenn assessment (2.12, 1.33-3.39 per month), and pulmonary to systemic flow ratio (1.23, 1.08-1.41 per 0.1 unit) were associated with aorto-pulmonary collateral burden. Aorto-pulmonary collateral burden was not associated with death/transplantation (hazard ratio 1.19, 95% confidence interval 0.37-3.85), pulmonary artery (sub-hazard ratio 1.38, 0.32-2.61), or aorto-pulmonary collateral interventions (sub-hazard ratio 1.11, 0.21-5.76). Longer post-Norwood length of stay was associated with greater risk of death/transplantation (hazard ratio 1.22 per week, 95% confidence interval 1.08-1.38), but lower risk of aorto-pulmonary collateral intervention (sub-hazard ratio 0.86 per week, 95% confidence interval 0.75-0.98). Time to pre-bidirectional Glenn catheterisation was associated with lower risk of pulmonary artery (sub-hazard ratio 0.80 per month, 95% confidence interval 0.65-0.98) and aorto-pulmonary collateral intervention (sub-hazard ratio 0.79, 0.63-0.99). Probability of moderate/severe aorto-pulmonary collateral burden increased with left-to-right shunt (22.5% at <1.0, 57.6% at >1.4) and the age at pre-bidirectional Glenn catheterisation (10.6% at <2 months, 56.9% at >5 months).

CONCLUSIONS

Aorto-pulmonary collateral burden is common after Norwood procedure and increases as age at bidirectional Glenn increases. As expected, higher pulmonary to systemic flow ratio is a marker for greater aorto-pulmonary collateral burden pre-bi-directional Glenn; aorto-pulmonary collateral burden does not confer risk of death/transplantation or pulmonary artery intervention.

Utility of the NEONATE Score at an Institution that Routinely Performs the Hybrid Procedure for Hypoplastic Left Heart Syndrome

NEONATE score > 17 has been proposed as a risk factor for interstage mortality/cardiac transplant (IM/T) for patients with single ventricle physiology. Hybrid procedure is assigned 6 points, the highest possible score for that surgical variable. Most centers reserve the hybrid procedure for high-risk patients. Goal of this study was to evaluate the NEONATE score at a center that routinely performs the hybrid procedure. Retrospective chart review of patients undergoing the hybrid procedure was performed (2008-2021). Demographics and variables used for the NEONATE score were collected. Maximization of Youden's J Statistic used to determine cohort-specific optimal threshold for patients undergoing comprehensive Stage II procedure (H-CSII) versus those with IM/T (H-IM/T). Total of 120 patients met inclusion criteria (H-CSII = 105, H-IM/T = 15). Gestational age was median 39 weeks (IQR 38, 39) and birth weight was 3.18 kg (2.91, 3.57). No patient was discharged with opiates or required post-operative extracorporeal circulatory support. Optimal threshold, as selected by maximizing Youden's J Statistic, was 22. Score > 22 had a positive predictive value of 0.33 (95% CI 0.12-0.62), negative predictive values of 0.90 (95% CI 0.83-0.95), and accuracy of 0.83 (95% CI 0.75-0.90) for IM/T. At a center that routinely performs the hybrid procedure, value of > 22 had the highest accuracy. This suggests that the hybrid procedure is not necessarily intrinsically a risk-factor for IM/T, but rather patient selection for the hybrid procedure may play a larger role at centers that do not routinely perform this procedure.

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.

Novel Dosing and Monitoring of Aspirin in Infants With Systemic-to-Pulmonary Artery Shunt Physiology: the SOPRANO Study

OBJECTIVES

Provision of pulmonary blood flow with a systemic-to-pulmonary artery shunt is essential in some patients with cyanotic congenital heart disease. Traditionally, aspirin (ASA) has been used to prevent thrombosis. We evaluated ASA dosing with 2 separate antiplatelet monitoring tests for accuracy and reliability.

METHODS

This is a retrospective, pre-post intervention single center study. Two cohorts were evaluated; the pre-intervention group used thromboelastography platelet mapping (TPM) and post-intervention used VerifyNow aspirin reactivity unit (ARU) monitoring. The primary endpoint was to compare therapeutic effect of TPM and ARU with regard to platelet inhibition. Inadequate platelet inhibition was defined as TPM <50% inhibition and ARU >550.

RESULTS

Data from 49 patients were analyzed: 25 in the TPM group and 24 in the ARU group. Baseline characteristics were similar amongst the cohorts. The TPM group had significantly more patients with inadequate platelet inhibition (14 [56%] vs 2 [8%]; p = 0.0006) and required escalation with additional thromboprophylaxis (15 [60%] vs 5 [21%]). There was no difference in shunt thrombosis (1 [2%] vs 0 [0%]; p = 0.32), cyanosis requiring early re-intervention (9 [36%] vs 14 [58%]; p = 0.11), or bleeding (15 [60%] vs 14 [58%]; p = 0.66).

CONCLUSION

With similar cohorts and the same ASA-dosing nomogram, ARU monitoring resulted in a reduced need for escalation of care and concomitant thromboprophylaxis with no difference in adverse outcomes. Our study suggests ARU monitoring compared with TPM may be a more reliable therapeutic platelet inhibition test for determining ASA sensitivity in children with congenital heart disease requiring systemic-to-pulmonary artery shunt.

Center-level factors associated with shorter length of stay following stage 1 palliation: An analysis of the national pediatric cardiology quality improvement collaborative registry

BACKGROUND

Stage 1 single ventricle palliation (S1P) has the longest length of stay (LOS) of all benchmark congenital heart operations. Center-level factors contributing to prolonged hospitalization are poorly defined.

METHODS

We analyzed data from infants status post S1P included in the National Pediatric Cardiology Quality Improvement Collaborative Phase II registry. Our primary outcome was patient-level LOS with days alive and out of hospital before stage 2 palliation (S2P) used as a balancing measure. We compared patient and center-level characteristics across quartiles for median center LOS, and used multivariable regression to calculate center-level factors associated with LOS after adjusting for case mix.

RESULTS

Of 2,510 infants (65 sites), 2037 (47 sites) met study criteria (61% male, 61% white, 72% hypoplastic left heart syndrome). There was wide intercenter variation in LOS (first quartile centers: median 28 days [IQR 19, 46]; fourth quartile: 62 days [35, 95], P < .001). Mortality prior to S2P did not differ across quartiles. Shorter LOS correlated with more pre-S2P days alive and out of hospital, after accounting for readmissions (correlation coefficient -0.48, P < .001). In multivariable analysis, increased use of Norwood with a right ventricle to pulmonary artery conduit (aOR 2.65 [1.1, 6.37]), shorter bypass time (aOR 0.99 per minute [0.98,1.0]), fewer additional cardiac operations (aOR 0.46 [0.22, 0.93]), and increased use of NG tubes rather than G tubes (aOR 7.03 [1.95, 25.42]) were all associated with shorter LOS centers.

CONCLUSIONS

Modifiable center-level practices may be targets to standardize practice and reduce overall LOS across centers.

Prevalence and associated factors of post-traumatic stress disorder in parents whose infants have single ventricle heart disease

INTRODUCTION

Post-traumatic stress disorder occurs in parents of infants with CHD, contributing to psychological distress with detrimental effects on family functioning and well-being. We sought to determine the prevalence and factors associated with post-traumatic stress disorder symptoms in parents whose infants underwent staged palliation for single ventricle heart disease.

MATERIALS AND METHODS

A large longitudinal multi-centre cohort study evaluated 215 mothers and fathers for symptoms of post-traumatic stress disorder at three timepoints, including post-Norwood, post-Stage II, and a final study timepoint when the child reached approximately 16 months of age, using the self-report questionnaire Impact of Event Scale - Revised.

RESULTS

The prevalence of probable post-traumatic stress disorder post-Norwood surgery was 50% of mothers and 39% of fathers, decreasing to 27% of mothers and 24% of fathers by final follow-up. Intrusive symptoms such as flashbacks and nightmares and hyperarousal symptoms such as poor concentration, irritability, and sudden physical symptoms of racing heart and difficulty breathing were particularly elevated in parents. Higher levels of anxiety, reduced coping, and decreased satisfaction with parenting were significantly associated with symptoms of post-traumatic stress disorder in parents. Demographic and clinical variables such as parent education, pre-natal diagnosis, medical complications, and length of hospital stay(s) were not significantly associated with symptoms of post-traumatic stress disorder.

DISCUSSION

Parents whose infants underwent staged palliation for single ventricle heart disease often reported symptoms of post-traumatic stress disorder. Symptoms persisted over time and routine screening might help identify parents at-risk and prompt referral to appropriate supports.

Improving Outcomes for Infants After Cardiopulmonary Bypass Surgery for Congenital Heart Disease: A Commentary on Recent Randomized Controlled Trials

The recent NITRIC and STRESS trials demonstrate opportunities to perform pragmatic large randomized trials in congenital heart disease. We discuss lessons learnt from these trials which can inform future trial design and conduct in the field of pediatric heart surgery.

Longitudinal Follow-Up of Children With HLHS and Association Between Norwood Shunt Type and Long-Term Outcomes: The SVR III Study

OBJECTIVE

In the SVR trial (Single Ventricle Reconstruction), newborns with hypoplastic left heart syndrome were randomly assigned to receive a modified Blalock-Taussig-Thomas shunt (mBTTS) or a right ventricle-to-pulmonary artery shunt (RVPAS) at Norwood operation. Transplant-free survival was superior in the RVPAS group at 1 year, but no longer differed by treatment group at 6 years; both treatment groups had accumulated important morbidities. In the third follow-up of this cohort (SVRIII [Long-Term Outcomes of Children With Hypoplastic Left Heart Syndrome and the Impact of Norwood Shunt Type]), we measured longitudinal outcomes and their risk factors through 12 years of age.

METHODS

Annual medical history was collected through record review and telephone interviews. Cardiac magnetic resonance imaging (CMR), echocardiogram, and cycle ergometry cardiopulmonary exercise tests were performed at 10 through 14 years of age among participants with Fontan physiology. Differences in transplant-free survival and complication rates (eg, arrhythmias or protein-losing enteropathy) were identified through 12 years of age. The primary study outcome was right ventricular ejection fraction (RVEF) by CMR, and primary analyses were according to shunt type received. Multivariable linear and Cox regression models were created for RVEF by CMR and post-Fontan transplant-free survival.

RESULTS

Among 549 participants enrolled in SVR, 237 of 313 (76%; 60.7% male) transplant-free survivors (mBTTS, 105 of 147; RVPAS, 129 of 161; both, 3 of 5) participated in SVRIII. RVEF by CMR was similar in the shunt groups (RVPAS, 51±9.6 [n=90], and mBTTS, 52±7.4 [n=75]; P=0.43). The RVPAS and mBTTS groups did not differ in transplant-free survival by 12 years of age (163 of 277 [59%] versus 144 of 267 [54%], respectively; P=0.11), percentage predicted peak Vo2 for age and sex (74±18% [n=91] versus 72±18% [n=84]; P=0.71), or percentage predicted work rate for size and sex (65±20% versus 64±19%; P=0.65). The RVPAS versus mBTTS group had a higher cumulative incidence of protein-losing enteropathy (5% versus 2%; P=0.04) and of catheter interventions (14 versus 10 per 100 patient-years; P=0.01), but had similar rates of other complications.

CONCLUSIONS

By 12 years after the Norwood operation, shunt type has minimal association with RVEF, peak Vo2, complication rates, and transplant-free survival. RVEF is preserved among the subgroup of survivors who underwent CMR assessment. Low transplant-free survival, poor exercise performance, and accruing morbidities highlight the need for innovative strategies to improve long-term outcomes in patients with hypoplastic left heart syndrome.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT0245531.

Hypoplastic Left Heart Syndrome: Signaling & Molecular Perspectives, and the Road Ahead

Hypoplastic left heart syndrome (HLHS) is a lethal congenital heart disease (CHD) affecting 8-25 per 100,000 neonates globally. Clinical interventions, primarily surgical, have improved the life expectancy of the affected subjects substantially over the years. However, the etiological basis of HLHS remains fundamentally unclear to this day. Based upon the existing paradigm of studies, HLHS exhibits a multifactorial mode of etiology mediated by a complicated course of genetic and signaling cascade. This review presents a detailed outline of the HLHS phenotype, the prenatal and postnatal risks, and the signaling and molecular mechanisms driving HLHS pathogenesis. The review discusses the potential limitations and future perspectives of studies that can be undertaken to address the existing scientific gap. Mechanistic studies to explain HLHS etiology will potentially elucidate novel druggable targets and empower the development of therapeutic regimens against HLHS in the future.

Long-term outcomes of tricuspid valve intervention during stage 2 palliation in patients with a single right ventricle

OBJECTIVES

In patients with single ventricle physiology and a systemic right ventricle, tricuspid valve regurgitation increases the risk of adverse outcomes, and tricuspid valve intervention at the time of staged palliation further increases that risk in the postoperative period. However, long-term outcomes of valve intervention in patients with significant regurgitation during stage 2 palliation have not been established. The purpose of this study is to evaluate the long-term outcomes after tricuspid valve intervention during stage 2 palliation in patients with right ventricular dominant circulation in a multicenter study.

METHODS

The study was performed using the Single Ventricle Reconstruction Trial and Single Ventricle Reconstruction Follow-up 2 Trial datasets. Survival analysis was performed to describe the association among valve regurgitation, intervention, and long-term survival. Cox proportional hazards modeling was used to estimate the longitudinal association of tricuspid intervention and transplant-free survival.

RESULTS

Patients with tricuspid regurgitation at stage 1 or 2 had worse transplant-free survival (hazard ratio, 1.61; 95% confidence interval, 1.12-2.32; hazard ratio, 2.3; 95% confidence interval 1.39-3.82). Those with regurgitation who underwent concomitant valve intervention at stage 2 were significantly more likely to die or undergo heart transplantation compared with those with regurgitation who did not (hazard ratio, 2.93; confidence interval, 2.16-3.99). Patients with tricuspid regurgitation at the time of the Fontan had favorable outcomes regardless of valve intervention.

CONCLUSIONS

The risks associated with tricuspid regurgitation in patients with single ventricle physiology do not appear to be mitigated by valve intervention at the time of stage 2 palliation. Patients who underwent valve intervention for tricuspid regurgitation at stage 2 had significantly worse survival compared with patients with tricuspid regurgitation who did not.

Cardiac arrest and cardiopulmonary resuscitation in pediatric patients with cardiac disease: a narrative review

Children with cardiac disease are at a higher risk of cardiac arrest as compared to healthy children. Delivering adequate cardiopulmonary resuscitation (CPR) can be challenging due to anatomic characteristics, risk profiles, and physiologies. We aimed to review the physiological aspects of resuscitation in different cardiac physiologies, summarize the current recommendations, provide un update of current literature, and highlight knowledge gaps to guide research efforts. We specifically reviewed current knowledge on resuscitation strategies for high-risk categories of patients including patients with single-ventricle physiology, right-sided lesions, right ventricle restrictive physiology, left-sided lesions, myocarditis, cardiomyopathy, pulmonary arterial hypertension, and arrhythmias. Cardiac arrest occurs in about 1% of hospitalized children with cardiac disease, and in 5% of those admitted to an intensive care unit. Mortality after cardiac arrest in this population remains high, ranging from 30 to 65%. The neurologic outcome varies widely among studies, with a favorable neurologic outcome at discharge observed in 64%-95% of the survivors. Risk factors for cardiac arrest and associated mortality include younger age, lower weight, prematurity, genetic syndrome, single-ventricle physiology, arrhythmias, pulmonary arterial hypertension, comorbidities, mechanical ventilation preceding cardiac arrest, surgical complexity, higher vasoactive-inotropic score, and factors related to resources and institutional characteristics. Recent data suggest that Extracorporeal membrane oxygenation CPR (ECPR) may be a valid strategy in centers with expertise. Overall, knowledge on resuscitation strategies based on physiology remains limited, with a crucial need for further research in this field. Collaborative and interprofessional studies are highly needed to improve care and outcomes for this high-risk population. What is Known: • Children with cardiac disease are at high risk of cardiac arrest, and cardiopulmonary resuscitation may be challenging due to unique characteristics and different physiologies. • Mortality after cardiac arrest remains high and neurologic outcomes suboptimal. What is New: • We reviewed the unique resuscitation challenges, current knowledge, and recommendations for different cardiac physiologies. • We highlighted knowledge gaps to guide research efforts aimed to improve care and outcomes in this high-risk population.

Cardiac Magnetic Resonance Imaging to Determine Single Ventricle Function in a Pediatric Population is Feasible in a Large Trial Setting: Experience from the Single Ventricle Reconstruction Trial Longitudinal Follow up

The Single Ventricle Reconstruction (SVR) Trial was a randomized prospective trial designed to determine survival advantage of the modified Blalock-Taussig-Thomas shunt (BTTS) vs the right ventricle to pulmonary artery conduit (RVPAS) for patients with hypoplastic left heart syndrome. The primary aim of the long-term follow-up (SVRIII) was to determine the impact of shunt type on RV function. In this work, we describe the use of CMR in a large cohort follow up from the SVR Trial as a focused study of single ventricle function. The SVRIII protocol included short axis steady-state free precession imaging to assess single ventricle systolic function and flow quantification. There were 313 eligible SVRIII participants and 237 enrolled, ages ranging from 10 to 12.5 years. 177/237 (75%) participants underwent CMR. The most common reasons for not undergoing CMR exam were requirement for anesthesia (n = 14) or ICD/pacemaker (n = 11). A total of 168/177 (94%) CMR studies were diagnostic for RVEF. Median exam time was 54 [IQR 40-74] minutes, cine function exam time 20 [IQR 14-27] minutes, and flow quantification time 18 [IQR 12-25] minutes. There were 69/177 (39%) studies noted to have intra-thoracic artifacts, most common being susceptibility artifact from intra-thoracic metal. Not all artifacts resulted in non-diagnostic exams. These data describe the use and limitations of CMR for the assessment of cardiac function in a prospective trial setting in a grade-school-aged pediatric population with congenital heart disease. Many of the limitations are expected to decrease with the continued advancement of CMR technology.

Predictors of Human Milk Feeding and Direct Breastfeeding for Infants with Single Ventricle Congenital Heart Disease: Machine Learning Analysis of the National Pediatric Cardiology Quality Improvement Collaborative Registry

OBJECTIVE

To identify factors that support or limit human milk (HM) feeding and direct breastfeeding (BF) for infants with single ventricle congenital heart disease at neonatal stage 1 palliation (S1P) discharge and at stage 2 palliation (S2P) (∼4-6 months old).

STUDY DESIGN

Analysis of the National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC) registry (2016-2021; 67 sites). Primary outcomes were any HM, exclusive HM, and any direct BF at S1P discharge and at S2P. The main analysis involved multiple phases of elastic net logistic regression on imputed data to identify important predictors.

RESULTS

For 1944 infants, the strongest predictor domain areas included preoperative feeding, demographics/social determinants of health, feeding route, clinical course, and site. Significant findings included: preoperative BF was associated with any HM at S1P discharge (OR = 2.02, 95% CI = 1.74-3.44) and any BF at S2P (OR = 2.29, 95% CI = 1.38-3.80); private/self-insurance was associated with any HM at S1P discharge (OR = 1.91, 95% CI = 1.58-2.47); and Black/African-American infants had lower odds of any HM at S1P discharge (OR = 0.54, 95% CI = 0.38-0.65) and at S2P (0.57, 0.30-0.86). Adjusted odds of HM/BF practices varied among NPC-QIC sites.

CONCLUSIONS

Preoperative feeding practices predict later HM and BF for infants with single ventricle congenital heart disease; therefore, family-centered interventions focused on HM/BF during the S1P preoperative time are needed. These interventions should include evidence-based strategies to address implicit bias and seek to minimize disparities related to social determinants of health. Future research is needed to identify supportive practices common to high-performing NPC-QIC sites.

Genetic and clinical variables act synergistically to impact neurodevelopmental outcomes in children with single ventricle heart disease

BACKGROUND

Recent large-scale sequencing efforts have shed light on the genetic contribution to the etiology of congenital heart defects (CHD); however, the relative impact of genetics on clinical outcomes remains less understood. Outcomes analyses using genetics are complicated by the intrinsic severity of the CHD lesion and interactions with conditionally dependent clinical variables.

METHODS

Bayesian Networks were applied to describe the intertwined relationships between clinical variables, demography, and genetics in a cohort of children with single ventricle CHD.

RESULTS

As isolated variables, a damaging genetic variant in a gene related to abnormal heart morphology and prolonged ventilator support following stage I palliative surgery increase the probability of having a low Mental Developmental Index (MDI) score at 14 months of age by 1.9- and 5.8-fold, respectively. However, in combination, these variables act synergistically to further increase the probability of a low MDI score by 10-fold. The absence of a damaging variant in a known syndromic CHD gene and a shorter post-operative ventilator support increase the probability of a normal MDI score 1.7- and 2.4-fold, respectively, but in combination increase the probability of a good outcome by 59-fold.

CONCLUSIONS

Our analyses suggest a modest genetic contribution to neurodevelopmental outcomes as isolated variables, similar to known clinical predictors. By contrast, genetic, demographic, and clinical variables interact synergistically to markedly impact clinical outcomes. These findings underscore the importance of capturing and quantifying the impact of damaging genomic variants in the context of multiple, conditionally dependent variables, such as pre- and post-operative factors, and demography.

A complicated Glenn procedure: risk factors and association with adverse long-term neurodevelopmental and functional outcomes

OBJECTIVES

To determine potentially modifiable risk factors for a complicated Glenn procedure (cGP) and whether a cGP predicted adverse neurodevelopmental and functional outcomes. A cGP was defined as post-operative death, heart transplant, extracorporeal life support, Glenn takedown, or prolonged ventilation.

METHODS

All 169 patients having a Glenn procedure from 2012 to 2017 were included. Neurodevelopmental assessments were performed at age 2 years in consenting survivors (n = 156/159 survivors). The Bayley Scales of Infant and Toddler Development-3rd Edition (Bayley-III) and the Adaptive Behavior Assessment System-2nd Edition (ABAS-II) were administered. Adaptive functional outcomes were determined by the General Adaptive Composite (GAC) score from the ABAS-II. Predictors of outcomes were determined using univariate and multiple variable linear or Cox regressions.

RESULTS

Of patients who had a Glenn procedure, 10/169 (6%) died by 2 years of age and 27/169 (16%) had a cGP. Variables statistically significantly associated with a cGP were the inotrope score on post-operative day 1 (HR 1.04, 95%CI 1.01, 1.06; p = 0.010) and use of inhaled nitric oxide post-operatively (HR 7.31, 95%CI 3.19, 16.76; p < 0.001). A cGP was independently statistically significantly associated with adverse Bayley-III Cognitive (ES -10.60, 95%CI -17.09, -4.11; p = 0.002) and Language (ES -11.43, 95%CI -19.25, -3.60; p = 0.004) scores and adverse GAC score (ES -14.89, 95%CI -22.86, -6.92; p < 0.001).

CONCLUSIONS

Higher inotrope score and inhaled nitric oxide used post-operatively were associated with a cGP. A cGP was independently associated with adverse 2-year neurodevelopmental and functional outcomes. Whether early recognition and intervention for risk of a cGP can prevent adverse outcomes warrants study.

Textbook outcome for the Norwood operation-an informative quality metric in congenital heart surgery

Objectives

To develop a more holistic measure of center performance than operative mortality, we created a composite "textbook outcome" for the Norwood operation using several postoperative end points. We hypothesized that achieving the textbook outcome would have a positive prognostic and financial impact.

Methods

This was a single-center retrospective study of primary Norwood operations from 2005 to 2021. Through interdisciplinary clinician consensus, textbook outcome was defined as freedom from operative mortality, open or catheter-based reintervention, 30-day readmission, extracorporeal membrane oxygenation, cardiac arrest, reintubation, length of stay >75%ile from Society of Thoracic Surgeons data report (66 days), and mechanical ventilation duration >75%ile (10 days). Multivariable logistic regression and Cox proportional hazards modeling were used to determine predictive factors for textbook outcome achievement and association of the outcome with long-term survival, respectively.

Results

Overall, 30% (58/196) of patients met the textbook outcome. Common reasons for failure to attain textbook outcome were prolonged ventilation (68/138, 49%) and reintubation (63/138, 46%). In multivariable analysis, greater weight (odds ratio [OR], 2.11; 95% confidence interval [CI], 1.17-3.95; P = .02) was associated with achieving the textbook outcome whereas preoperative shock (OR, 0.36; 95% CI, 0.13-0.87; P = .03) and longer bypass time (OR, 0.99; 95% CI, 0.98-1.00; P = .002) were negatively associated. Patients who met the outcome incurred fewer hospital costs ($152,430 [141,798-177,983] vs $269,070 [212,451-372,693], P < .001), and after adjusting for patient factors, achieving textbook outcome was independently associated with decreased risk of all-cause mortality (hazard ratio, 0.45; 95% CI, 0.22-0.89; P = .02).

Conclusions

Outcomes continue to improve within congenital heart surgery, making operative mortality a less-sensitive metric. The Norwood textbook outcome may represent a balanced measure of a successful episode of care.

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.

Risk factors for mortality in patients with hypoplastic left heart syndrome after the Norwood procedure

OBJECTIVES

Several studies have reported mortality risk factors associated with hypoplastic left heart syndrome (HLHS). However, these data are ambiguous and mainly focused on the independent effects of these factors. We examined both the independent and the cumulative effects of preoperative risk factors for poor outcome in patients undergoing the Norwood procedure. Moreover, we studied the risk factors associated with prolonged initial hospital stays in these patients.

METHODS

We performed a retrospective national 18-year observational study of preoperative risk factors for 1 year, as well as total follow-up mortality or need for transplant in patients with HLHS (N = 99) born in Finland between 1 January 2004 and 31 December 2021.

RESULTS

Overall, one-year survival was 85.6%. In a multivariable analysis, having a major extracardiac anomaly and being small for gestational age were significant predictors of one-year mortality or the need for a transplant. Aortic atresia was a predictor of total follow-up mortality. An analysis of the cumulative effect indicated that the presence of 2 risk factors was associated with higher mortality.

CONCLUSIONS

HLHS remains the defect with the highest procedural risks for mortality in paediatric cardiac surgery. From a prognostic point of view, recognition of independent preoperative risk factors as well as the cumulative effect of risk factors for mortality is essential.The results of this study were presented orally at the 55th Annual Meeting of the Association for European Paediatric and Congenital Cardiology, Geneva, Switzerland, 28 May 2022.

Machine Learning to Predict Interstage Mortality Following Single Ventricle Palliation: A NPC-QIC Database Analysis

There is high risk of mortality between stage I and stage II palliation of single ventricle heart disease. This study aimed to leverage advanced machine learning algorithms to optimize risk-prediction models and identify features most predictive of interstage mortality. This study utilized retrospective data from the National Pediatric Cardiology Quality Improvement Collaborative and included all patients who underwent stage I palliation and survived to hospital discharge (2008-2019). Multiple machine learning models were evaluated, including logistic regression, random forest, gradient boosting trees, extreme gradient boost trees, and light gradient boosting machines. A total of 3267 patients were included with 208 (6.4%) interstage deaths. Machine learning models were trained on 180 clinical features. Digoxin use at discharge was the most influential factor resulting in a lower risk of interstage mortality (p < 0.0001). Stage I surgery with Blalock-Taussig-Thomas shunt portended higher risk than Sano conduit (7.8% vs 4.4%, p = 0.0002). Non-modifiable risk factors identified with increased risk of interstage mortality included female sex, lower gestational age, and lower birth weight. Post-operative risk factors included the requirement of unplanned catheterization and more severe atrioventricular valve insufficiency at discharge. Light gradient boosting machines demonstrated the best performance with an area under the receiver operative characteristic curve of 0.642. Advanced machine learning algorithms highlight a number of modifiable and non-modifiable risk factors for interstage mortality following stage I palliation. However, model performance remains modest, suggesting the presence of unmeasured confounders that contribute to interstage risk.

Preoperative versus postoperative survival in patients with univentricular heart: a nationwide, retrospective study of patients born in 1990-2015

OBJECTIVES

Few data exist on mortality among patients with univentricular heart (UVH) before surgery. Our aim was to explore the results of intention to perform surgery by estimating preoperative vs postoperative survival in different UVH subgroups.

DESIGN

Retrospective.

SETTING

Tertiary centre for congenital cardiology and congenital heart surgery.

PARTICIPANTS

All 595 Norwegian children with UVH born alive from 1990 to 2015, followed until 31 December 2020.

RESULTS

One quarter (151/595; 25.4%) were not operated. Among these, only two survived, and 125/149 (83.9%) died within 1 month. Reasons for not operating were that surgery was not feasible in 31.1%, preoperative complications in 25.2%, general health issues in 23.2% and parental decision in 20.5%. In total, 327/595 (55.0%) died; 283/327 (86.5%) already died during the first 2 years of life. Preoperative survival varied widely among the UVH subgroups, ranging from 40/65 (61.5%) among patients with unbalanced atrioventricular septal defect to 39/42 (92.9%) among patients with double inlet left ventricle. Postoperative survival followed a similar pattern. Postoperative survival among patients with hypoplastic left heart syndrome (HLHS) improved significantly (5-year survival, 42.5% vs 75.3% among patients born in 1990-2002 vs 2003-2015; p<0.0001), but not among non-HLHS patients (65.7% vs 72.6%; p=0.22)-among whom several subgroups had a poor prognosis similar to HLHS. A total of 291/595 patients (48.9%) had Fontan surgery CONCLUSIONS: Surgery was refrained in one quarter of the patients, among whom almost all died shortly after birth. Long-term prognosis was largely determined during the first 2 years. There was a strong concordance between preoperative and postoperative survival. HLHS survival was improved, but non-HLHS survival did not change significantly. This study demonstrates the complications and outcomes encountering newborns with UVH at all major stages of preoperative and operative treatment.

Decreased left heart flow in fetal lambs causes left heart hypoplasia and pro-fibrotic tissue remodeling

Low blood flow through the fetal left heart is often conjectured as an etiology for hypoplastic left heart syndrome (HLHS). To investigate if a decrease in left heart flow results in growth failure, we generate left ventricular inflow obstruction (LVIO) in mid-gestation fetal lambs by implanting coils in their left atrium using an ultrasound-guided percutaneous technique. Significant LVIO recapitulates important clinical features of HLHS: decreased antegrade aortic valve flow, compensatory retrograde perfusion of the brain and ascending aorta (AAo) from the arterial duct, severe left heart hypoplasia, a non-apex forming LV, and a thickened endocardial layer. The hypoplastic AAo have miRNA-gene pairs annotating to cell proliferation that are inversely differentially expressed by bulk RNA-seq. Single-nucleus RNA-seq of the hypoplastic LV myocardium shows an increase in fibroblasts with a reciprocal decrease in cardiomyocyte nuclei proportions. Fibroblasts, cardiomyocytes and endothelial cells from hypoplastic myocardium have increased expression of extracellular matrix component or fibrosis genes with dysregulated fibroblast growth factor signaling. Hence, a severe sustained ( ~ 1/3 gestation) reduction in fetal left heart flow is sufficient to cause left heart hypoplasia. This is accompanied by changes in cellular composition and gene expression consistent with a pro-fibrotic environment and aberrant induction of mesenchymal programs.

Children with single ventricle heart disease have a greater increase in sRAGE after cardiopulmonary bypass

INTRODUCTION

Reducing cardiopulmonary bypass (CPB) induced inflammatory injury is a potentially important strategy for children undergoing multiple operations for single ventricle palliation. We sought to characterize the soluble receptor for advanced glycation end products (sRAGE), a protein involved in acute lung injury and inflammation, in pediatric patients with congenital heart disease and hypothesized that patients undergoing single ventricle palliation would have higher levels of sRAGE following bypass than those with biventricular physiologies.

METHODS

This was a prospective, observational study of children undergoing CPB. Plasma samples were obtained before and after bypass. sRAGE levels were measured and compared between those with biventricular and single ventricle heart disease using descriptive statistics and multivariate analysis for risk factors for lung injury.

RESULTS

sRAGE levels were measured in 40 patients: 19 with biventricular and 21 with single ventricle heart disease. Children undergoing single ventricle palliation had a higher factor and percent increase in sRAGE levels when compared to patients with biventricular circulations (4.6 vs. 2.4, p = 0.002) and (364% vs. 181%, p = 0.014). The factor increase in sRAGE inversely correlated with the patient's preoperative oxygen saturation (Pearson correlation (r) = -0.43, p = 0.005) and was positively associated with red blood cell transfusion (coefficient = 0.011; 95% CI: 0.004, 0.017; p = 0.001).

CONCLUSIONS

Children with single ventricle physiology have greater increase in sRAGE following CPB as compared to children undergoing biventricular repair. Larger studies delineating the role of sRAGE in children undergoing single ventricle palliation may be beneficial in understanding how to prevent complications in this high-risk population.

Utilizing technology to expand home monitoring to high-risk infants with CHD

Infants born with single ventricle physiology that require an aorto-pulmonary shunt are at high risk for sudden cardiac death, particularly during the interstage period between the first-stage palliation and the second-stage palliation. Home monitoring programs have decreased interstage mortality in the hypoplastic left heart syndrome population prompting programs to expand the home monitoring program to other high-risk populations. At our mid-sized program, we implemented the Locus Health home monitoring platform first in the hypoplastic left heart syndrome population, then expanding to the single ventricle shunt population. Interstage mortality for the hypoplastic left heart syndrome population after initiation of the home monitoring program went from 18% prior to 2009 to 7% as of the end of 2020 (n = 99), with 2.8% mortality from 2013 to 2020 and 0% mortality since initiation of the Locus program in 2017. Caregiver surveys done prior to discharge and then 3 weeks later were used to document caregiver experience using the digital home monitoring program. Caregivers reported overall positive experience with the digital application, with 91.8% stating that they felt confident taking care of their baby at home. Transitioning the home monitoring program from a traditional binder to an iPad with the Locus Health application allowed us to expand the program, utilize the electronic medical record, bill for the service, and demonstrate positive experiences for caregivers. Overall engagement and adherence with the program by caregivers were 50.94 and 45.45%, with a total of 112 patient episodes. Reimbursement from private insurance providers was 22% of the billed amount for 2020.

The teammate trial: Study design and rationale tacrolimus and everolimus against tacrolimus and MMF in pediatric heart transplantation using the major adverse transplant event (MATE) score

BACKGROUND

Currently there are no immunosuppression regimens FDA-approved to prevent rejection in pediatric heart transplantation (HT). In recent years, everolimus (EVL) has emerged as a potential alternative to standard tacrolimus (TAC) as the primary immunosuppressant to prevent rejection that may also reduce the risk of cardiac allograft vasculopathy (CAV), chronic kidney disease (CKD) and cytomegalovirus (CMV) infection. However, the 2 regimens have never been compared head-to-head in a randomized trial. The study design and rationale are reviewed in light of the challenges inherent in rare disease research.

METHODS

The TEAMMATE trial (IND 127980) is the first multicenter randomized clinical trial (RCT) in pediatric HT. The primary purpose is to evaluate the safety and efficacy of EVL and low-dose TAC (LD-TAC) compared to standard-dose TAC and mycophenolate mofetil (MMF). Children aged <21 years at HT were randomized (1:1 ratio) at 6 months post-HT to either regimen, and followed for 30 months. Children with recurrent rejection, multi-organ transplant recipients, and those with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m² were excluded. The primary efficacy hypothesis is that, compared to TAC/MMF, EVL/LD-TAC is more effective in preventing 3 MATEs: acute cellular rejection (ACR), CKD and CAV. The primary safety hypothesis is that EVL/LD-TAC does not have a higher cumulative burden of 6 MATEs (antibody mediated rejection [AMR], infection, and post-transplant lymphoproliferative disorder [PTLD] in addition to the 3 above). The primary endpoint is the MATE score, a composite, ordinal surrogate endpoint reflecting the frequency and severity of MATEs that is validated against graft loss. The study had a target sample size of 210 patients across 25 sites and is powered to demonstrate superior efficacy of EVL/LD-TAC. Trial enrollment is complete and participant follow-up will be completed in 2023.

CONCLUSION

The TEAMMATE trial is the first multicenter RCT in pediatric HT. It is anticipated that the study will provide important information about the safety and efficacy of everolimus vs tacrolimus-based regimens and will provide valuable lessons into the design and conduct of future trials in pediatric HT.

Hypoplastic Left Heart Syndrome: A Review

Hypoplastic left heart syndrome is a rare and poorly understood congenital disorder featuring a univentricular myocardium, invariably resulting in early childhood death if left untreated. The process to palliate this congenital cardiomyopathy is of high complexity and may include invasive interventions in the first week of life. The preferred treatment strategy involves a staged correction with 3 surgical procedures at different points in time. The Norwood procedure is usually performed within the first weeks of life and aims to increase systemic circulation and relieve pulmonary vascular pressure. This procedure is followed by the bidirectional Glenn and the Fontan procedures in later life, which offer to decrease stress in the ventricular chamber. The prognosis of children with this disease has greatly improved in the past decades; however, it is still largely driven by multiple modifiable and nonmodifiable variables. Novel and clever alternatives have been proposed to improve the survival and neurodevelopment of these patients, although they are not used as standard of care in all centers. The neurodevelopmental outcomes among these patients have received particular attention in the last decade in light to improve this very limiting associated comorbidity that compromises quality of life.

Initial Counseling Prior to Palliation for Hypoplastic Left Heart Syndrome: 2021 vs 2011

We sought to examine current practices and changes in practice regarding initial counseling for families of patients with hypoplastic left heart syndrome (HLHS) given the evolution of options and outcomes over time. Counseling (Norwood with Blalock-Taussig-Thomas shunt (NW-BTT), NW with right ventricle to pulmonary artery conduit (NW-RVPA), hybrid palliation, heart transplantation, or non-intervention/hospice (NI)) for patients with HLHS were queried via questionnaire of pediatric care professionals in 2021 and compared to identical questionnaire from 2011. Of 322 respondents in 2021 (39% female), 299 respondents were cardiologists (92.9%), 17cardiothoracic surgeons (5.3%), and 6 were nurse practitioners (1.9%). Respondents were largely from North America (96.9%). In 2021, NW-RVPA procedure was the preferred palliation for standard risk HLHS patient (61%) and was preferred across all US regions (p < 0.001). NI was offered as an option by 71.4% of respondents for standard risk patients and was the predominant strategy for patients with end-organ dysfunction, chromosomal abnormality, and prematurity (52%, 44%, and 45%, respectively). The hybrid procedure was preferred for low birth-weight infants (51%). In comparison to the identical 2011 questionnaire (n = 200), the NW-RVPA was endorsed more in 2021 (61% vs 52%, p = 0.04). For low birth-weight infants, hybrid procedure was more recommended than in 2011 (51% vs 21%, p < 0.001). The NW-RVPA operation is the most recommended strategy throughout the US for infants with HLHS. The hybrid procedure for low birth-weight infants is increasingly recommended. NI continues to be offered even in standard risk patients with HLHS.

Cell-based therapy to boost right ventricular function and cardiovascular performance in hypoplastic left heart syndrome: Current approaches and future directions

Congenital heart disease remains one of the most frequently diagnosed congenital diseases of the newborn, with hypoplastic left heart syndrome (HLHS) being considered one of the most severe. This univentricular defect was uniformly fatal until the introduction, 40 years ago, of a complex surgical palliation consisting of multiple staged procedures spanning the first 4 years of the child's life. While survival has improved substantially, particularly in experienced centers, ventricular failure requiring heart transplant and a number of associated morbidities remain ongoing clinical challenges for these patients. Cell-based therapies aimed at boosting ventricular performance are under clinical evaluation as a novel intervention to decrease morbidity associated with surgical palliation. In this review, we will examine the current burden of HLHS and current modalities for treatment, discuss various cells therapies as an intervention while delineating challenges and future directions for this therapy for HLHS and other congenital heart diseases.

Impact of Reintervention During Stage 1 Palliation Hospitalization: A National, Multicenter Study

BACKGROUND

Stage 1 palliation (S1P) for hypoplastic left heart syndrome remains associated with high morbidity and mortality. Previous studies on burden of reinterventions did not include patients who remain hospitalized before stage 2 palliation (S2P). This study described the rate of reintervention during S1P hospitalization and sought to determine the impact of reintervention on outcomes.

METHODS

All participants enrolled in phase II of the National Pediatric Cardiology Quality Improvement Collaborative after S1P were included in this study. The primary outcome was the rate of reintervention during hospitalization after S1P and before hospital discharge or S2P. Reintervention was defined as 1 or more unplanned interventional cardiac catheterizations or surgical reoperations.

RESULTS

Between March 1, 2016 and October 1, 2019, 1367 participants underwent S1P and 339 (24.8%) had a reintervention; most commonly to address the source of pulmonary blood flow. Gestational age, weight at S1P, atrioventricular septal defect, heterotaxy, preoperative pulmonary artery bands, hybrid S1P, and an additional bypass run or early extracorporeal membrane oxygenation were significantly associated with reintervention. Participants in the reintervention group experienced higher rates of nearly all postoperative complications, were less likely to be discharged before S2P (57.1% vs 86%; P < .001), and more likely to experience in-hospital mortality (17% vs 5%; P < .001).

CONCLUSIONS

Unplanned reintervention during hospitalization after S1P palliation occurred in 25% of participants in a large, registry-based national cohort. Participants who underwent reintervention were more likely to remain as inpatient and were less likely to survive to S2P. Reintervention was associated with a multitude of postoperative complications that affect survival and long-term outcome.

Normothermic Versus Hypothermic Norwood Procedure

BACKGROUND

Either deep hypothermia with circulatory arrest or hypothermic perfusion with antegrade selective cerebral perfusion is used during the Norwood procedure for hypoplastic left heart syndrome. Normothermic perfusion has been described for pediatric patients. The aim of this study was to compare the early outcomes of patients undergoing the Norwood procedure with antegrade selective cerebral perfusion under hypothermia with the procedure under normothermia.

METHODS

From 2005 to 2020, 117 consecutive patients with hypoplastic left heart syndrome underwent the Norwood procedure: 68 (58.2%) under hypothermia and 49 (41.8%) under normothermia. Antegrade selective cerebral perfusion flow was adjusted to maintain right radial arterial pressure above 50 mm Hg, and a flow rate of 40 to 50 mL kg^-1 min^-1. Baseline characteristics, operative data, and postoperative outcomes including lactate recovery time were compared.

RESULTS

The baseline characteristics and cardiovascular diagnosis were similar in both groups. The normothermic group had a significantly shorter bypass time (in minutes) of 90.31 (±31.60) versus 123.63 (±25.33), a cross-clamp time of 45.24 (±16.35) versus 81.93 (±16.34), and an antegrade selective cerebral perfusion time of 25.61 (±13.84) versus 47.30 (±14.35) (P < .001). There were no statistically significant differences in the immediate postoperative course, or in terms of in-hospital mortality, which totaled 9 (18.4%) in the normothermic group, and 10 (14.9%) in the hypothermic group (P = .81).

CONCLUSION

The normothermic Norwood procedure with selective cerebral perfusion is feasible and safe in terms of in-hospital mortality and short-term outcomes. It is comparable to the standard hypothermic Norwood with selective cerebral perfusion.