The Optimal Timing of Stage 2 Palliation for Hypoplastic Left Heart Syndrome: An Analysis of the Pediatric Heart Network Single Ventricle Reconstruction Trial Public Data Set

Risk Factors for Death or Transplant After Stage 2 Palliation for Single Ventricle Heart Disease

Background

For infants with single ventricle heart disease, the time after stage 2 procedure (S2P) is believed to be a lower risk period compared with the interstage period; however, significant morbidity and mortality still occur.

Objectives

This study aimed to identify risk factors for mortality or transplantation referral between S2P surgery and the first birthday.

Methods

Retrospective cohort analysis of infants in the National Pediatric Cardiology Quality Improvement Collaborative who underwent staged single ventricle palliation from 2016 to 2022 and survived to S2P. Multivariable logistic regression and classification and regression trees were performed to identify risk factors for mortality and transplantation referral after S2P.

Results

Of the 1,455 patients in the cohort who survived to S2P, 5.2% died and 2.3% were referred for transplant. Overall event rates at 30 and 100 days after S2P were 2% and 5%, respectively. Independent risk factors for mortality and transplantation referral included the presence of a known genetic syndrome, shunt type at stage 1 procedure (S1P), tricuspid valve repair at S1P, longer time to extubation and reintubation after S1P, ≥ moderate tricuspid regurgitation prior to S2P, younger age at S2P, and the risk groups identified in the classification and regression tree analysis (extracorporeal membrane oxygenation after S1P and longer S2P cardiopulmonary bypass time without extracorporeal membrane oxygenation).

Conclusions

Mortality and transplantation referral rates after S2P to 1 year of age remain high ∼7%. Many of the identified risk factors after S2P are similar to those established for interstage factors around the S1P, whereas others may be unique to the period after S2P.

Outcomes of Children With Hypoplastic Left Heart Syndrome and Heart Failure on Medical Therapy

Background

Systemic right ventricle (RV) dysfunction is associated with lower transplant-free survival (TFS) in hypoplastic left heart syndrome (HLHS), but the likelihood of functional improvement and utility of heart failure (HF) medications is not understood.

Objectives

The authors aimed to describe TFS, HF medication use, and surgical interventions in HLHS patients with RV dysfunction with and without subsequent improvement in function.

Methods

The SickKids HF Database is a retrospective cohort that includes all pediatric HLHS patients with RV dysfunction lasting >30 days. We compared TFS, HF medications, and surgical interventions in HLHS patients with and without functional normalization.

Results

Of 99 patients with HLHS and RV dysfunction, 52% had normalized function for ≥30 days. TFS at 2 years after dysfunction onset was lower in those without normalization (14% vs 78%, P < 0.001). Patients without normalization were less likely to reach target dosing (TD) of HF medications (27% vs 47% on 1 medication at TD, P < 0.001) and undergo Fontan completion (7% vs 53%, P < 0.001). Clinical factors associated with improved TFS were normalization of function for ≥30 days, onset of dysfunction after bidirectional Glenn, and exposure to ACE inhibition.

Conclusions

Our cohort of HLHS patients with systemic RV dysfunction demonstrated a novel finding of improved TFS in those with functional normalization for ≥30 days. Achieving TD of HF medications was associated with improved outcomes. This may reflect patient stability and tolerance for HF medication more than its therapeutic effect, but it can help inform decisions to proceed with surgical palliation or list for transplant.

Timing of Cardiac Surgical Interventions and Postoperative Mortality in Children With Severe Congenital Heart Defects Across Europe: Data From the EUROlinkCAT Study

BACKGROUND

The purpose of this study was to evaluate the timing of the first cardiac surgery, the number of cardiac surgeries performed, and 30-day postoperative mortality rate for children with severe congenital heart defects (sCHDs) in their first 5 years of life.

METHODS AND RESULTS

This was a population-based data linkage cohort study linking information from 9 European congenital anomaly registries to vital statistics and hospital databases. Data were extracted for 5693 children with sCHDs born from 1995 to 2004. Subgroup analyses were performed for specific types of sCHD. Children with sCHDs underwent their first surgical intervention at a median age of 3.6 (95% CI, 2.6-4.5) weeks. The timing of the first surgery for most subtypes of sCHD was consistent across Europe. In the first 5 years of life, children with hypoplastic left heart underwent the most cardiac surgeries, with a median of 4.4 (95% CI, 3.1-5.6). The 30-day postoperative mortality rate in children aged <1 year ranged from 1.1% (95% CI, 0.5%-2.1%) for tetralogy of Fallot to 23% (95% CI, 12%-37%) for Ebstein anomaly. The 30-day postoperative mortality rate was highest for children undergoing surgery in the first month of life. Overall 5-year survival for sCHD was <90% for all sCHDs, except transposition of the great arteries, tetralogy of Fallot, and coarctation of the aorta.

CONCLUSIONS

There were no major differences among the 9 regions in the timing, 30-day postoperative mortality rate, and number of operations performed for sCHD. Despite an overall good prognosis for most congenital heart defects, some lesions were still associated with substantial postoperative death.

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.

Impact of Ventricular Dysfunction and Atrioventricular Valve Regurgitation on Pre-Fontan Attrition

BACKGROUND

There is a significant incidence of pre-Fontan attrition-defined as failure to undergo Fontan completion-after superior cavopulmonary connection. This study investigated the impact of at least moderate ventricular dysfunction (VD) and atrioventricular valve regurgitation (AVVR) on pre-Fontan attrition.

METHODS

This single-center retrospective cohort study included all infants who underwent Norwood palliation from 2008 to 2020 and subsequently underwent superior cavopulmonary connection. Pre-Fontan attrition was defined as death, listing for heart transplantation before Fontan completion, or unsuitability for Fontan completion. The study's secondary outcome was transplant-free survival.

RESULTS

Pre-Fontan attrition occurred in 34 of 267 patients (12.7%). Isolated VD was not associated with attrition. However, patients with isolated AVVR had 5 times the odds of attrition (odds ratio, 5.4; 95% CI 1.8-16.2), and patients with both VD and AVVR had 20 times the odds of attrition (odds ratio, 20.1; 95% CI 7.7-52.8) compared with patients without VD or AVVR. Only patients with both VD and AVVR had significantly worse transplant-free survival compared with patients without VD or AVVR (hazard ratio, 7.7; 95% CI 2.8-21.6).

CONCLUSIONS

The additive effect of VD and AVVR is a powerful contributor to pre-Fontan attrition. Future research investigating therapies that can mitigate the degree of AVVR may help improve Fontan completion rates and long-term outcomes.

Research Enterprise of the Congenital Heart Surgeons' Society 2018 to 2023: History, Accomplishments, Transformation, and Challenges

The history of the research arm of the Congenital Heart Surgeons' Society (CHSS) through 2017 was contained within two prior publications that covered CHSS history in general. The present article is the first to focus explicitly on the research enterprise, with emphasis on the period 2018 to 2023. During this time, the challenges of continuing to build multiple cohorts with lifelong follow-up and to transform the enterprise to a premiere research organization became manifest. Although continuing its commitment to produce impactful research results and to educate the Kirklin/Ashburn Fellow, the research team devoted considerable effort to defining the problems of cohort relevance, workflow, data management, long-term patient follow-up, CHSS member engagement, and the regulatory burden. The team wrote a proposal outlining ways to solve the challenges. A major change from a single-institution "Data Center" to a two-institution Center for Research & Quality (CRQ) was made, assuring increased faculty members and resources. The proposed changes to structure and process began execution in mid-2022. A second Kirklin/Ashburn Fellowship position was created. Between 2018 and 2022, the CRQ produced 17 publications and launched five new research initiatives. This article chronicles the exciting five-year period in which the CHSS research enterprise began a transformation with the intent to become the premiere research organization in the world in the specialty of congenital cardiac surgery.

The Academic Impact of Congenital Heart Surgeons' Society (CHSS) Studies

PURPOSE

We reviewed all 64 articles ever published by The Congenital Heart Surgeons' Society (CHSS) Data Center to estimate the academic impact of these peer-reviewed articles.

MATERIALS AND METHODS

The Congenital Heart Surgeons' Society has performed research based on 12 Diagnostic Inception Cohorts. The first cohort (Transposition) began enrolling patients on January 1, 1985. We queried PubMed to determine the number of publications that referenced each of the 64 journal articles generated by the datasets of the 12 Diagnostic Inception Cohorts that comprise the CHSS Database. Descriptive summaries of the data were tabulated using mean with standard deviation and median with range.

RESULTS

Sixty-four peer-reviewed papers have been published based on the CHSS Database. Fifty-nine peer-reviewed articles have been published based on the 12 Diagnostic Inception Cohorts, and five additional articles have been published based on Data Science. Excluding the recently established Diagnostic Inception Cohort for patients with Ebstein malformation of tricuspid valve, the number of papers published per cohort ranged from 1 for coarctation to 11 for transposition of the great arteries. The 11 articles generated from the CHSS Transposition Cohort were referenced by a total of 111 articles (median number of references per journal article = 9 [range = 0-22, mean = 10.1]). Overall, individual articles were cited by an average of 11 (mean), and a maximum of 41 PubMed-listed publications. Overall, these 64 peer-reviewed articles based on the CHSS Database were cited 692 times in PubMed-listed publications. The first CHSS peer-reviewed article was published in 1987, and during the 35 years from 1987 to 2022, inclusive, the annual number of CHSS publications has ranged from 0 to 7, with a mean of 1.8 publications per year (median = 1, mode = 1).

CONCLUSION

Congenital Heart Surgeons' Society studies are widely referenced in the pediatric cardiac surgical literature, with over 10 citations per published article. These cohorts provide unique information unavailable in other sources of data. A tool to access this analysis is available at: [https://data-center.chss.org/multimedia/files/2022/CAI.pdf].

Hybrid Palliation for Hypoplastic Left Heart Syndrome: Role of Echocardiography

Hypoplastic left heart syndrome is a spectrum of complex congenital cardiac defects. Although in borderline cases, biventricular repair is a viable option, in the majority of cases, univentricular palliation is the treatment of choice. Hybrid palliation can be a valid alternative to classic Norwood operation in the neonatal period, especially in selected cases such as high-risk patients or borderline left ventricles. Echocardiography is the main diagnostic modality in this pediatric population, from the fetal diagnosis to the subsequent surgical steps of palliative treatment. Hybrid palliation is performed after birth and is characterized by surgical banding of the pulmonary arteries along with transcatheter stenting of the ductus arteriosus. There are some peculiar aspects of cardiac imaging that characterize this type of palliation, and that should be considered in the different phases before and after the procedure. We aimed to review the current literature about the role of echocardiography in the management of patients with hypoplastic left heart undergoing hybrid palliation.

Clinical and haemodynamic variables associated with intensive care unit length of stay and early adverse outcomes after the Norwood procedure

OBJECTIVES

This study was performed to determine the clinical and haemodynamic variables associated with early adverse outcomes after the neonatal Norwood procedure.

METHODS

Patients who underwent the neonatal Norwood procedure between 2001 and 2019 were included. The patient diagnosis, morphological characteristics and haemodynamic parameters were analysed to identify factors associated with length of stay (LOS) in the intensive care unit (ICU) and mortality during the stay.

RESULTS

A total of 322 patients were depicted. The median age and weight at the Norwood procedure were 9 days and 3.2 kg, respectively. Certain morphological and preoperative parameters, such as birth weight below 2.5 kg, restrictive atrial septal defect, extracardiac anomalies and the diameter of the ascending aorta, were found to be associated with the LOS in the ICU. Analysis using early postoperative haemodynamic variables revealed that systolic arterial pressure, diastolic arterial pressure, serum lactate levels and reduced ventricular function at 2 days postoperatively were associated with the LOS in the ICU. Birth weight <2.5 kg (P = 0.010), a restrictive atrial septal defect (P = 0.001) and smaller ascending aorta (P = 0.039) were associated with death in the ICU. Reduced ventricular function, lower systolic aortic pressure and higher lactate levels at various time points (P < 0.05) were also associated with ICU deaths. The LOS in the ICU was significantly associated with late mortality (P < 0.001, Hazard Ratio (HR) = 1.015).

CONCLUSIONS

The LOS in the ICU after the Norwood procedure was predicted by early postoperative haemodynamic variables, suggesting that good early postoperative haemodynamics determine early recovery. A prolonged stay in the ICU after the Norwood procedure was associated with late mortality.

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.

Prescription of cardiovascular medication in children with congenital heart defects across six European Regions from 2000 to 2014: data from the EUROlinkCAT population-based cohort study

OBJECTIVES

Advances in surgical management strategies have substantially reduced fatality from congenital heart defects (CHD). Decreased infant mortality might be expected, consequentially to result in greater morbidity in older children due to complications later in childhood and adolescence. This study aims to evaluate the use of cardiovascular medication (CVM) as an indicator of disease burden in children born with CHD in the first 10 years of life.

DESIGN

Population-based cohort study.

SETTING

Six population-based registries from the European Surveillance of Congenital Anomalies (EUROCAT) network participated. Data from live born children with major congenital anomalies (CA) born from 2000 to 2014 were linked to prescription databases. Four groups of children were analysed: CA, CHD, severe CHD (sCHD) and ventricular septal defect (VSD) without sCHD. Live born children without CA were included as reference group.

PARTICIPANTS

We obtained data on 61 038 children born with a CA, including 19 678 with CHD, 3392 with sCHD, 12 728 children with VSD without sCHD, and 1 725 496 reference children.

RESULTS

Children born with sCHD were the most likely to receive a CVM prescription (42.9%, 95% CI, 26.3 to 58.5) in the first year of life compared with 13.3% (6.7 to 22.0) of children with any CHD, 5.9% (3.7 to 8.7) of children with any CA and 0.1% (0.0 to 0.1) of reference children. Medication was less likely to be prescribed after the first year of life for sCHD; 18.8% (14.8 to 23.1) for children 1-4 years and 15.8% (12.0 to 20.1) 5-9 years. Children with sCHD were most likely to receive a diuretic (36.4%, 18.6 to 54.5), an antihypertensive (6.9%, 3.7 to 11.3) or a beta-blocker (5.5%, 2.9 to9.2).

CONCLUSION

Almost half of all children with sCHD were prescribed CVM in their first year of life. For all four groups of children with anomalies, the proportion of children with a CVM prescription decreased with age.

Impact of hypoxemia and re-interventions on clinical outcomes after bidirectional cavopulmonary shunt

OBJECTIVES

We sought to investigate the impact of early postoperative low arterial oxygen saturation on mortality and morbidity after bidirectional cavopulmonary shunt.

METHODS

The medical records of all patients who underwent bidirectional cavopulmonary shunt between 2013 and 2018 were reviewed.

RESULTS

A total of 164 patients were included in this study. Forty-seven patients underwent reintervention during hospital stay at median 7 days after bidirectional cavopulmonary shunt. Before reintervention, 30 patients were intubated or had SpO2 of less than 75%. All re-interventions for Glenn pathway obstruction and 4 out of 5 venovenous coil embolization resulted in hospital discharge, while high mortality was observed after other re-interventions (atrioventricular valve surgery, thrombolysis, systemic ventricular outflow obstruction relief, extracorporeal membrane oxygenation implantation, and diaphragmatic plication). Additional aortopulmonary shunt with pulmonary artery discontinuation was performed in 8 patients who showed severe cyanosis with median SpO2 of 59% under maximal ventilation support. In univariable Cox regression analysis, the associated factors for mortality before total cavopulmonary connection were reduced ventricular function (HR 6.89, 95% CI 1.76-26.9, P value 0.006), greater than moderate atrioventricular valve regurgitation (HR 5.89, 95% CI 1.70-20.4, P value 0.005), SpO2 1 hour after extubation (HR 0.87, 95% CI 0.80-0.96, P value 0.004), and mean pulmonary artery pressure 1 hour after extubation (HR 1.14, 95% CI 1.02-1.26, P value 0.016).

CONCLUSIONS

After bidirectional cavopulmonary shunt, unacceptable cyanosis persisted with various etiologies. Low arterial oxygen saturation within 1 hour after extubation is significantly associated with high mortality after bidirectional cavopulmonary shunt.

The Failed Bidirectional Glenn Shunt: Risk Factors for Poor Outcomes and the Role of Early Reoperation

Background: Bidirectional Glenn shunt (BDG) failure carries high morbidity and mortality but the clinical factors associated with failure and the optimal management strategy are understudied. Methods: A total of 217 patients undergoing BDG at our institution between 1989 and 2020 were retrospectively reviewed and categorized as success or failure. Failure was defined as the need for reoperation (BDG takedown, reoperation for correction of cardiac defect, and/or transplantation) at any time postoperatively; operative mortality (death attributable to BDG malfunction occurring during the index hospitalization for BDG or within 30 days of discharge); or late mortality (death directly attributable to BDG malfunction occurring prior to Fontan or next-stage palliation). Univariate and binary logistic regression analyses were performed. Results: BDG failure occurred in 14 (6.5%) patients. Univariate predictors were: hypoplastic left heart syndrome (P = .037), right ventricular (RV) dominance (P = .010), greater pre-BDG pulmonary vascular resistance (PVR) (P = .012), concomitant atrioventricular valve repair (P = .020), prolonged pleural drainage (P = .001), intensive care unit (P<.001) and hospital (P = .002) stays, and extracorporeal membrane oxygenation (ECMO) requirement (P<.001). Multivariate predictors were: RV dominance (P = .002), greater PVR (P = .041), ICU (P<.001) and hospital (P = .020) stays, and need for ECMO (P<.001). As many as 10 of 14 (71%) patients with BDG failure died. Reoperation was performed for 10 patients with BDG failure. Five reoperation patients survived until discharge, with four patients alive at last follow-up (mean 7.9 years). Survivors underwent reoperation earlier than nonsurvivors (36 vs. 94 days). Conclusions: BDG failure carries high mortality, but preoperative predictors and postoperative indicators of failure exist. Early BDG takedown and insertion of aorta-pulmonary shunt may allow survival.

Post-operative Renal Failure, Shunt Type and Mortality after Norwood Palliation

BACKGROUND

The Single Ventricle Reconstruction (SVR) trial demonstrated increased risk of death or heart transplant one year post-Norwood in subjects randomized to Blalock-Taussig shunts (mBTS) compared to right ventricle-to-pulmonary artery (RV-PA) shunts. We used the SVR public use database to evaluate incidence and risk factors for post-operative renal failure and relationships between renal failure, shunt type and outcomes post-Norwood.

METHODS

Post-operative renal failure was defined a-priori as a 3-fold rise in creatinine from baseline, or dialysis use, within 7 days of Norwood. We used multivariate logistic regression to evaluate risk factors for post-operative renal failure and Cox hazard regression to determine the association between post-operative renal failure and one-year post-Norwood mortality.

RESULTS

Overall, post-operative renal failure occurred in 8.4% (46/544) with risk factors including receipt of a mBTS (aOR 3.3, p=0.02), low center volume (aOR 2.7, p=0.005), presence of ≥2 pre-op complications (aOR 4.0, p<0.001), low birth weight (aOR 3.2, p=0.002), post-operative heart block (aOR 8.5, p=0.001), and delayed sternal closure (aOR 5.3, p=0.026). Renal failure was an independent risk factor for one-year mortality (aHR 1.9, p=0.019). Assessing interaction by shunt type, mortality risk associated with renal failure was greatest in the RV-PA shunt group (aHR 3.3 versus RV-PA shunt without renal failure, p=0.001), but was also increased in the mBTS group (aHR 1.9, p=0.03).

CONCLUSIONS

Post-operative renal failure is common after Norwood and is independently associated with mortality. Although renal failure is more common after mBTS, the highest mortality risk with renal failure occurs after RV-PA shunt.

Preoperative risk factors influencing inter-stage mortality after the Norwood procedure

OBJECTIVES

With improvements in early survival after the stage I palliation (S1P) Norwood procedure for hypoplastic left heart syndrome (HLHS) and its variants, inter-stage death accounts for an increasing proportion of mortality. Our aim was to identify the risk factors for inter-stage mortality.

METHODS

The records of 322 neonates with HLHS or a variant who underwent the Norwood procedure at our centre between 2001 and 2019 were retrospectively analysed.

RESULTS

The diagnoses included 271 neonates with HLHS (84%) and 51 with variants (16%). Aortic atresia was observed in 138 (43%) patients, mitral atresia in 91 (28%), extracardiac anomalies in 42 (13%) and genetic disorder in 14 (4%). The median age and weight of the patients at the S1P Norwood procedure were 9 (interquartile range: 7-12) days and 3.2 (2.9-3.5) kg, respectively. The median cardiopulmonary bypass time was 137 (107-163) min. Modified Blalock-Taussig shunts were used in 159 (49%) and unvalved right ventricle-to-pulmonary artery shunts in 163 (51%) patients. The number of inter-stage deaths was as follows: between S1P and stage II palliation (S2P), 61 including 38 early (<30 days) and 23 late (>30 days) deaths, and between S2P and stage III palliation, 32 deaths. Low birth weight (<2.5 kg) (odds ratio 4.37, P = 0.020) and restrictive atrial septum (odds ratio 2.97, P = 0.013) were identified as risks for early mortality. Low birth weight [hazard ratio (HR) 0.99/g, P = 0.002] was a risk for inter-stage mortality between S1P and S2P. Extracardiac anomalies (HR 4.75, P = 0.049) and significant pre-S1P atrioventricular valve regurgitation (HR: 7.72, P = 0.016) were risks for inter-stage mortality between S2P and stage III palliation. Other anatomical variables including aortic atresia, anatomical subtypes and the diameter of the ascending aorta nor shunt type were not identified as risk factors for mortality during any inter-stage period.

CONCLUSIONS

The risk factors for inter-stage attrition after the Norwood procedure were different between each stage. Preoperative factors, including birth weight, restrictive atrial septum and extracardiac anomalies, adversely affected the inter-stage mortality.

Tricuspid valve repair in children with hypoplastic left heart syndrome: impact of timing and mechanism on outcome

OBJECTIVES

Our aim was to evaluate the results of tricuspid valve repair (TVr) in patients with hypoplastic left heart syndrome during staged reconstruction, focussing on the timing of the repair and the mechanisms of tricuspid regurgitation (TR).

METHODS

Records of 44 children with hypoplastic left heart syndrome who underwent a total of 62 tricuspid valve (TV) procedures during staged reconstruction were retrospectively analysed.

RESULTS

TVr was performed before stage II in 4 (9%) patients, at stage II in 23 (52%) patients, between stages II and III in 3 (7%) patients and at stage III in 14 (32%) patients. The median age at the first TV procedure was 5 months. At surgery, TR emanated commonly from the anteroseptal commissure in 21 (48%) patients. Anterior leaflet prolapse was observed most frequently (n = 23; 52%), followed by septal leaflet restriction (n = 22; 50%), dilated annulus (n = 21; 48%) and cleft anterior leaflet (n = 9; 21%). Surgical techniques included commissuroplasty in 27 (61.4%) patients, leaflet adaptation in 20 (44%) patients, partial annuloplasty in 11 (25%) patients, chordal reconstruction in 10 (23%) patients and cleft closure in 10 (23%) patients. Among all 44 patients, 27 (61%) patients had preoperative grade III TR and 17 (39%) patients had grade IV; postoperatively, there were no patients with grade IV, 25 patients with grade III (57%), 10 patients with grade II (23%) and 6 patients with grade I (14%). Fifteen patients required redo TV surgeries. Reoperation-free survival was 52% at 5 years. Lower weight at initial TVr predicted mortality [hazard ratio (HR) 0.7, P = 0.044] and reoperation (HR 0.8, P = 0.015). TVr before stage II was a risk for both reoperation (HR 5.5, P = 0.042) and TV replacement (HR 36.9, P = 0.013). Among morphological factors, septal leaflet restriction was a risk for reoperation (HR 4.7, P = 0.017) and anterior (HR 4.7, P = 0.037) and posterior (HR 7.3, P = 0.015) leaflet chordal anomaly for TV replacement.

CONCLUSIONS

Anterior leaflet prolapse and septal leaflet restriction are the main mechanisms of TR in hypoplastic left heart syndrome. Early-onset TR before stage II predicts worse outcome. Refinements to repair techniques in early infancy, especially for septal leaflet restrictions and chordal anomalies, are mandatory to improve outcomes.

Comparison of shunt types in the neonatal Norwood procedure for single ventricle

OBJECTIVES

The ideal shunt for pulmonary blood flow, modified Blalock-Taussig shunt (MBTS) or right ventricular-pulmonary artery conduit (RVPAC) is yet to be determined. This study aimed to evaluate outcomes after the Norwood procedure according to the type of shunt.

METHODS

A total of 322 neonates with hypoplastic left heart syndrome and related anomalies who underwent the Norwood procedure at our institution between 2001 and 2019 were divided into MBTS and RVPAC groups and the outcomes after the Norwood procedure were compared between the groups with respect to mortality after each staged procedure.

RESULTS

We identified 322 consequent patients who underwent neonatal Norwood procedure for hypoplastic left heart syndrome (271 patients, 84.2%) and its variant (51 patients, 15.8%). RVPAC was performed in 163 (50.6%) patients and MBTS was performed in 159 (49.4%). There were no differences in the rate of early death (11.0% vs 12.6%, P = 0.69) or late death (7.4% vs 6.9%, P = 0.87) between the 2 groups after the Norwood procedure, and no significant difference in the number of patients who reached bidirectional cavopulmonary shunt (77.9% vs 76.1%, P = 0.69), and there was no difference in mortality after bidirectional cavopulmonary shunt (12.3% vs 7.5%, P = 0.15) or Fontan completion rate (54.0% vs 52.2%, P = 0.42) between the 2 groups. Survival at 0.5, 1, 3 and 6 years after the Norwood procedure was 81.0%, 73.8%, 67.9% and 67.0% in patients with RVPAC and 77.1%, 73.3%, 69.1% and 67.9% in patients with MBTS. There was no significant difference in the survival between the 2 groups during the median follow-up of 2.6 (interquartile ranges: 0.3-8.4, maximal 18.8) years (P = 0.97).

CONCLUSIONS

In neonates undergoing the Norwood procedure, our available data of maximal 18.8 years follow-up showed no significant difference in early mortality, inter-stage attritions, or overall survival, between MBTS and RVPAC.

Risk Factors for Thrombus Formation at Stage 2 Palliation and Its Effect on Long-Term Outcome in Patients With Univentricular Heart

Thrombus formation is a feared complication following bidirectional cavopulmonary shunt (BCPS). We aimed to investigate the effect of thrombus formation on outcome. BCPS was performed in 525 patients at our center between 1998 and 2018. The impacts of thrombus formation on survival and probability of Fontan completion were analyzed, and risk factors for thrombus formation were examined. Thrombus formation occurred in 30 patients (5.7%). Compared with the remaining 495 patients, there was no significant difference in the median age at BCPS (4.9 vs 4.7 months; P = 0.587). However, unbalanced atrioventricular septal defects (17 vs 5%; P = 0.008) and preoperative ventricular dysfunction (23.3 vs 8%; P = 0.004) were more frequent in patients who developed a thrombus. Thrombolytic therapy was performed in all patients and surgical thrombus removal was required in 13 patients. In-hospital mortality was higher in patients with thrombus (30.0 vs 2.2%; P < 0.001). Of 505 hospital survivors, an estimated survival at 1 year after hospital discharge following BCPS was 84.4% (95% CI, 76.1-92.7%) in patients with thrombus and 96.8% (95% CI, 96.0-97.6%) in those without (P < 0.001). Cumulative incidence of Fontan completion at 3 years after BCPS was 52.8% (95% CI, 30.3-75.2%) in patients with thrombus and 90.1% (95% CI, 87.2-92.9%) in those without (P = 0.004). Higher left atrial pressure (OR = 1.165; P = 0.029) and longer cardiopulmonary bypass time (OR = 1.013, P = 0.001) at BCPS were independent risk factors for thrombus formation after BCPS. Thrombus formation after BCPS poses a significant risk for survival and Fontan completion. Preoperative higher left atrial pressure and longer cardiopulmonary bypass time are significant risk factors.

Surgical Timing and Outcomes of Unilateral Versus Bilateral Superior Cavopulmonary Anastomosis: An Analysis of Pediatric Heart Network Public Databases

Requiring bilateral superior cavopulmonary anastomosis (bSCPA) instead of unilateral superior cavopulmonary anastomosis (uSCPA) could influence surgical timing and outcomes. We compared surgical timing and outcomes for patients who underwent uSCPA to those who underwent bSCPA through use of the Pediatric Heart Network's public datasets for the Infant Single Ventricle trial and Single Ventricle Reconstruction trial. There was no statistically significant difference in median age at SCPA (158 vs. 150 days, p = 0.68), hospital length of stay (LOS) (7 vs. 7 days, p = 0.74), intensive care unit (ICU) LOS (4 vs. 5 days, p = 0.53), time requiring ventilator support (2 vs. 2 days, p = 0.51), or oxygen saturation at discharge (82 vs. 81%, p = 0.22) between the uSCPA and bSCPA groups, respectively. However, sub-analysis comparing only those who underwent early SCPA, at < 120 days of age, revealed significantly longer hospital LOS (8 vs. 13 days, p = 0.04), ICU LOS (5 vs. 11 days, p = 0.01), and time requiring ventilator support (2 vs. 4 days, p = 0.03) for the early bSCPA group when compared to the early uSCPA group. A multivariable logistic regression revealed bSCPA to be the only significant predictor of prolonged hospital LOS for patients who underwent early SCPA (odds ratio 4.1, 95% CI 1.2-14.2). Overall, there was no difference in surgical timing or outcome measures between uSCPA and bSCPA. However, early bSCPA, performed at < 120 days, had worse outcome measures than early uSCPA. Delaying elective bSCPA until at least 120 days of age could minimize morbidity in infants with bilateral superior venae cavae.

Interstage management of pulmonary blood flow after the Norwood procedure with right ventricle-to-pulmonary artery conduit

OBJECTIVES

Our goal was to assess the efficacy of managing pulmonary blood flow from the Norwood procedure with a right ventricle-to-pulmonary artery (RV-PA) conduit until stage 2 palliation (S2P).

METHODS

Among 48 consecutive patients undergoing the Norwood procedure between 2008 and 2018, 40 (83.3%) patients who survived to discharge were included in this study. The primary diagnosis was hypoplastic left heart syndrome in 28 (70%) patients and hypoplastic left heart syndrome variant in 12 (30%) patients. All patients received bilateral pulmonary artery banding. The median age and weight at the time of the Norwood procedure were 41 (25th-75th percentiles: 27-89) days and 3.2 (2.7-3.9) kg, respectively. In keeping with institutional strategy, S2P was undertaken when body weight exceeded 5.0 kg, and normal gross motor development was confirmed.

RESULTS

The RV-PA conduit was clipped in 28 (70%) patients during the perioperative period of the Norwood procedure, then partial unclipping was performed in 8 (20%) patients and full unclipping was performed in 20 (50%) patients. Before S2P, the median pulmonary-to-systemic blood flow ratio was 1.0 (0.7-1.3). The median age and weight at the time of S2P were 10.7 (9.0-12.9) months and 6.3 (5.5-7.1) kg, respectively. The survival rate 5 years after Norwood discharge was 85.3%. Pre-S2P pulmonary-to-systemic blood flow ratio was linearly correlated with greater interstage changes in systemic atrioventricular valve regurgitation (R2 = 0.223, P = 0.004).

CONCLUSIONS

Interstage management of pulmonary blood flow by RV-PA conduit clipping and gradual unclipping provided good interstage outcomes. The median pulmonary-to-systemic blood flow ratio could be controlled to 1.0 at pre-S2P catheter examination.

Interstage Home Monitoring for Infants With Single Ventricle Heart Disease: Education and Management: A Scientific Statement From the American Heart Association

This scientific statement summarizes the current state of knowledge related to interstage home monitoring for infants with shunt-dependent single ventricle heart disease. Historically, the interstage period has been defined as the time of discharge from the initial palliative procedure to the time of second stage palliation. High mortality rates during the interstage period led to the implementation of in-home surveillance strategies to detect physiologic changes that may precede hemodynamic decompensation in interstage infants with single ventricle heart disease. Adoption of interstage home monitoring practices has been associated with significantly improved morbidity and mortality. This statement will review in-hospital readiness for discharge, caregiver support and education, healthcare teams and resources, surveillance strategies and practices, national quality improvement efforts, interstage outcomes, and future areas for research. The statement is directed toward pediatric cardiologists, primary care providers, subspecialists, advanced practice providers, nurses, and those caring for infants undergoing staged surgical palliation for single ventricle heart disease.

A Comparison of Bidirectional Glenn vs. Hemi-Fontan Procedure: An Analysis of the Single Ventricle Reconstruction Trial Public Use Dataset

Patients with single ventricle (SV) heart defects have two primary surgical options for superior cavopulmonary connection (SCPC): bidirectional Glenn (BDG) and hemi-Fontan (HF). Outcomes based on type of SCPC have not been assessed in a multi-center cohort. This retrospective cohort study uses the Single Ventricle Reconstruction (SVR) Trial public use dataset. Infants who survived to SCPC were evaluated through 1 year of age, based on type of SCPC. The primary outcome was transplant-free survival at 1 year. The cohort included 343 patients undergoing SCPC across 15 centers in North America; 250 (73%) underwent the BDG. There was no difference between the groups in pre-SCPC clinical characteristics. Cardiopulmonary bypass times were longer [99 min (IQR 76, 126) vs 81 min (IQR 59, 116), p < 0.001] and use of deep hypothermic circulatory arrest (DHCA) more prevalent (51% vs 19%, p < 0.001) with HF. Patients who underwent HF had a higher likelihood of experiencing more than one post-operative complication (54% vs 41%, p = 0.05). There were no other differences including the rate of post-operative interventional cardiac catheterizations, length of stay, or survival at discharge, and there was no difference in transplant-free survival out to 1 year of age. Mortality after SCPC is low and there is no difference in mortality at 1 year of age based on type of SCPC. Differences in support time and post-operative complications support the preferential use of the BDG, but additional longitudinal follow-up is necessary to understand whether these differences have implications for long-term outcomes.

Superior Cavopulmonary Connection: Its Physiology, Limitations, and Anesthetic Implications

The superior cavopulmonary connection (SCPC) or "bidirectional Glenn" is an integral, intermediate stage in palliation of single ventricle patients to the Fontan procedure. The procedure, normally performed at 3 to 6 months of life, increases effective pulmonary blood flow and reduces the ventricular volume load in patients with single ventricle (parallel circulation) physiology. While the SCPC, with or without additional sources of pulmonary blood flow, cannot be considered a long-term palliation strategy, there are a subset of patients who require SCPC palliation for a longer interval than the typical patient. In this article, we will review the physiology of SCPC, the consequences of prolonged SCPC palliation, and modes of failure. We will also discuss strategies to augment pulmonary blood flow in the presence of an SCPC. The anesthetic considerations in SCPC patients will also be discussed, as these patients may present for noncardiac surgery from infancy to adulthood.

Estimating the optimal timing of surgery from observational data

Infants with hypoplastic left heart syndrome require an initial Norwood operation, followed some months later by a stage 2 palliation (S2P). The timing of S2P is critical for the operation's success and the infant's survival, but the optimal timing, if one exists, is unknown. We attempt to identify the optimal timing of S2P by analyzing data from the Single Ventricle Reconstruction Trial (SVRT), which randomized patients between two different types of Norwood procedure. In the SVRT, the timing of the S2P was chosen by the medical team; thus with respect to this exposure, the trial constitutes an observational study, and the analysis must adjust for potential confounding. To accomplish this, we propose an extended propensity score analysis that describes the time to surgery as a function of confounders in a discrete competing-risk model. We then apply inverse probability weighting to estimate a spline hazard model for predicting survival from the time of S2P. Our analysis suggests that S2P conducted at 6 months after the Norwood gives the patient the best post-S2P survival. Thus, we place the optimal time slightly later than a previous analysis in the medical literature that did not account for competing risks of death and heart transplantation.

Pediatric cardiac waitlist mortality-Still too high

Cardiac transplantation for children with end-stage cardiac disease with no other medical or surgical options is now standard. The number of children in need of cardiac transplant continues to exceed the number of donors considered "acceptable." Therefore, there is an urgent need to understand which recipients are in greatest need of transplant before becoming "too ill" and which "marginal" donors are acceptable in order to reduce waitlist mortality. This article reviewed primarily pediatric studies reported over the last 15 years on waitlist mortality around the world for the various subgroups of children awaiting heart transplant and discusses strategies to try to reduce the cardiac waitlist mortality.

Hypoplastic left heart syndrome: current modalities of treatment and outcomes

Hypoplastic left heart syndrome is a constellation of malformations which result from the severe underdevelopment of any left-sided cardiac structures. Once considered to be universally fatal, the prognosis for this condition has tremendously improved over the past four decades since the work of William Norwood in the early 1980s. Today, a staged surgical approach is applied for palliating this distinctive cohort of patients, in which they undergo three operative procedures in the first 10 years of their life. Advancements in medical technologies, surgical techniques, and our growing experience in the management of HLHS have made survival into adulthood a possibility. Through this review, we present the different phases of the staged approach with primary focus on stage 1-its modifications, current technique, alternatives, and latest outcomes.

Evolution of care pathways for babies with hypoplastic left heart syndrome: integrating mechanistic and clinical process investigation, standardization, and collaborative study

Since initial descriptions of staged palliation for hypoplastic left heart syndrome (HLHS) in the 1980’s, much has been learned about the pathophysiology of the single ventricle circulation. New therapies that leverage systems biology and clinical derivatives have been developed. While in-hospital mortality and morbidity for babies with HLHS have continued to improve, there remains a long (and daresay winding) road ahead to achieve ideal outcomes. Important variation in even these abbreviated in-hospital metrics persists among institutions and currently utilized prediction models explain only a small amount of this variation. Moreover, long-term survival and neurodevelopmental health for patients with HLHS are infrequently reported and remain suboptimal despite improved in-hospital outcomes. This focused review will describe the evolution of national outcomes for HLHS over time and the potential factors motivating improved time-related mortality. Emerging modifiable risk-factors that hold promise in terms of moving the needle for long-term success, including social determinants of health and the delineation of genetic profiles, will be discussed. Specifically, this review will integrate contemporary data based on the first murine HLHS models that suggest a genetically elicited modular phenotype with environmental factors known to impact the initial durability of surgical therapies. A comprehensive approach to the management of HLHS, which leverages both proactive transplantation and hybrid palliation, in addition to traditional Norwood palliation, will be emphasized to extend and match management to the complete spectrum of patient risk-profiles. Finally, we will explore the critical role that national collaboratives and quality reporting initiatives have played in improving outcomes and shifting the focus to more meaningful long-term survival and neurodevelopment.

Transplantation-free survival after Norwood surgery for hypoplastic left heart syndrome with aortic atresia: A Swedish national cohort study

BACKGROUND

Norwood surgery has been available in Sweden since 1993. In this national cohort study, we analysed transplantation-free survival after Norwood surgery for hypoplastic left heart syndrome with aortic atresia.

METHODS

Patients were identified from the complete national cohort of live-born with hypoplastic left heart syndrome/aortic atresia 1993-2010. Analysis of survival after surgery was performed using Cox proportional hazards models for the total cohort and for birth period and gender separately. Thirty-day mortality and inter-stage mortality were analysed. Patients were followed until September 2016.

RESULTS

The 1993-2010 cohort consisted of 208 live-born infants. Norwood surgery was performed in 121/208 (58%). The overall transplantation-free survival was 61/121 (50%). The survival was higher in the late period (10-year survival 63%) than in the early period (10-year survival 40%) (p = 0.010) and lower for female (10-year survival 34%) than for male patients (10-year survival 59%) (p = 0.002). Inter-stage mortality between stages I and II decreased from 23 to 8% (p = 0.008). For male patients, low birthweight in relation to gestational age was a factor associated with poor outcome.

CONCLUSION

The survival after Norwood surgery for hypoplastic left heart syndrome/aortic atresia improved by era of surgery, mainly explained by improved survival between stages I and II. Female gender was a significant risk factor for death or transplantation. For male patients, there was an increased risk of death when birthweight was lower than expected in relation to gestational age.

Survival, Neurocognitive, and Functional Outcomes After Completion of Staged Surgical Palliation in a Cohort of Patients With Hypoplastic Left Heart Syndrome

Background

Management of patients with hypoplastic left heart syndrome has benefited from advancements in medical and surgical care. Outcomes have improved, although survival and long‐term functional and cognitive deficits remain a concern.

Methods and Results

This is a cohort study of all consecutive patients with hypoplastic left heart syndrome undergoing surgical palliation at a single center. We aimed to examine demographic and perioperative factors from each surgical stage for their association with survival and neurocognitive outcomes. A total of 117 consecutive patients from 1996 to 2010 underwent surgical palliation. Seventy patients (60%) survived to the Fontan stage and 68 patients (58%) survived to undergo neurocognitive assessment at a mean (SD) age of 56.6 months (6.4 months). Full‐scale, performance, and verbal intelligence quotient, as well as visual‐motor integration mean (SD) scores were 86.7 (16.1), 86.3 (15.8), 88.8 (17.2), and 83.2 (14.8), respectively. On multivariable analysis, older age at Fontan, sepsis peri‐Norwood, lowest arterial partial pressure of oxygen postbidirectional cavopulmonary anastomosis, and presence of neuromotor disability pre‐Fontan were strongly associated with lower scores for all intelligence quotient domains. Older age at Fontan and sepsis peri‐Norwood remained associated with lower scores for all intelligence quotient domains in a subgroup analysis excluding patients with disability pre‐Fontan or with chromosomal abnormalities.

Conclusions

Older age at Fontan and sepsis are among independent predictors of poor neurocognitive outcomes for patients with hypoplastic left heart syndrome. Further studies are required to identify the appropriate age range for Fontan completion, balancing a lower risk of acute and long‐term hemodynamic complications while optimizing long‐term neurocognitive outcomes.

Recoarctation of the aorta after the Norwood procedure may be treated during the second stage of the surgical palliation

OBJECTIVES

Recoarctation of the aorta (re-CoA) after the Norwood procedure is traditionally treated during catheter-based aortoplasty (CB-A) performed as a separate procedure preceding stage II surgical palliation (S II SP). Our goal was to determine the efficacy of the protocol according to which re-CoA after the Norwood procedure in patients with hypoplastic left heart syndrome is treated during S II SP using hybrid catheter-based aortoplasty.

METHODS

We compared 2 groups of infants who developed re-CoA after the Norwood procedure and were treated at the same institution: In group I (n = 18), CB-A was traditionally performed before S II SP; in group II (n = 15), CB-A was performed during S II SP using a hybrid procedure (catheter access was through an aortic cannula routinely used for cardiopulmonary bypass). The right ventricular fractional area change was analysed.

RESULTS

The CB-A was performed effectively in both groups. S II SP was performed at a younger age in group II (5.4 ± 0.3 vs 6.0 ± 0.4 months; P = 0.003), with lower body weight (5.6 ± 0.5 vs 6.0 ± 0.4; P = 0.03, respectively). The duration of hospital stay did not differ between the groups (10.6 ± 6.2 vs 11.6 ± 6.4 days; P = 0.91). The right ventricular fractional area change measured before S II SP was higher in group I (39.7 ± 4.2% vs 36.8 ± 3.6%, respectively; P = 0.009), but the difference was not seen 1 month after S II SP (41.0 ± 5.6 vs 39.8 ± 4.1; P > 0.05). The total radiation dose was significantly lower in group II.

CONCLUSIONS

re-CoA after the Norwood procedure in patients with hypoplastic left heart syndrome can be treated effectively during S II SP using a hybrid procedure. The strategy allows for reduction of the total radiation dose and of the number of procedures and does not prolong the postoperative course, even in patients with decreased right ventricular systolic function.

Impact of Characteristics at Stage-2-Palliation on Outcome Following Fontan Completion

The optimal timing of stage-2-palliation (S2P) in single left ventricle is not clear. The aim of this study was to identify S2P related factors associated with outcomes after total cavopulmonary connection (TCPC), particularly relative to the dominant systemic ventricle. A total of 405 patients who underwent both S2P and TCPC at our institute between 1997 and 2017 was included. Patients were divided into two groups, dominant right ventricle (RV type, n = 235) and dominant left ventricle (LV type, n = 170). S2P related factors associated with mortality, postoperative ventricular function, and late exercise capacity following TCPC, were analyzed. The median age at S2P was 4 [3-7] and 6 [3-11] months in RV and LV type patients, respectively (p = 0.092). Survival after TCPC was similar in RV and LV type patients (p = 0.280). In those with RV type, risk factors for mortality following TCPC were older age (p < 0.001), heavier weight (p = 0.001), higher PAP (p < 0.001), higher TPG (p = 0.010), and lower SO2 (p = 0.008) at S2P. In those with LV type, no risk factor was identified. Risk factors for postoperative impaired ventricular function were older age and higher weight at S2P in both RV and LV type patients. Older age at S2P was also identified as a risk for inferior peak oxygen uptake (VO2) years after TCPC both in RV and LV type patients. Older age at S2P was associated with higher mortality after Fontan completion only in RV type patients. However, it was associated with postoperative ventricular dysfunction and lower exercise capacity after TCPC in both RV and LV type patients.

Update on pediatric heart failure

PURPOSE OF REVIEW

This review highlights recent advances in the diagnosis and management of children with heart failure. We emphasize the clinical approach to patient care in the areas of acute decompensated heart failure, chronic heart failure, and failure of the patient with single ventricle physiology.

RECENT FINDINGS

Important guidelines regarding the recognition and management of heart failure in children have been proposed and adopted, providing guidance for early recognition and ongoing management. Early diuresis, and avoidance of excessive inotropic agent use, in favor of milrinone as an inotropic-vasodilator agent, are emphasized. Close monitoring of airway pressures to improve ventricular filling, and extubation to positive pressure or high-flow nasal cannula therapy are also important. Chronic heart failure therapy requires combination treatment with diuretics, and the three major classes of drugs. Management of the failing Fontan requires attention to the hepatic, pulmonary and lymphatic circulations.

SUMMARY

Improved outcomes in children with heart failure are possible. Inherent in this success is the engagement of an interdisciplinary team-based approach to care, with early recognition and escalation of care for specific patients who are not improving as predicted.

Having to Be the One: Mothers Providing Home Care to Infants With Complex Cardiac Needs

BACKGROUND

Early diagnosis of complex congenital heart disease and advances in surgical interventions have resulted in remarkable improvements in prognoses and hospital survival. Although studies have provided insight into children's experiences with complex congenital heart disease after hospitalization, few have addressed parents' experiences providing care for infants with complex congenital heart disease who are discharged home with complex care needs after surgical palliation.

OBJECTIVES

To describe the perceptions and lived experiences of mothers of infants who were discharged from the hospital after surgery for complex congenital heart disease but were then readmitted to the hospital.

METHODS

Data collection and analysis for this pilot study were guided by grounded theory. From February through October 2017, interviews were conducted with 10 mothers about their experiences caring for their infants at home after surgery for complex congenital heart disease.

RESULTS

Analyses led to development of 1 category, "having to be the one," which had 3 properties: having no choice but to provide complex care at home, handling unexpected roles, and grappling with the possibility of death.

CONCLUSIONS

The category of "having to be the one" highlighted mothers' experiences providing medicalized care at home to their infants after complex cardiac surgery while managing other responsibilities, such as employment, busy households, and parenting other school-age children. The role of the caregiver is vital but demanding. Mothers' caregiving at home may be enhanced by nursing interventions such as routine screening for infant distress plus assessment for alterations in family coping or relational challenges that threaten family function.

The Superior Cavopulmonary Connection: History and Current Perspectives

The development of the superior cavopulmonary connection is a rich illustration of international influences in congenital cardiac surgery. The bidirectional Glenn and hemi-Fontan procedures have improved survival as both definitive and staged functional single ventricle palliation. The optimal timing of the second-stage superior cavopulmonary procedures varies by center but for low- and intermediate-risk patients, this may be within three to six months after the Norwood procedure. The list of risk factors continues to grow but the most frequently cited factors include atrioventricular valve regurgitation, decreased ventricular function, need for reintervention, and failure to attain nutritional and growth goals. Ongoing prospective, multi-institutional studies, particularly those fostered internationally by the World Society for Pediatric and Congenital Heart Surgery and other associations, will hopefully provide further clarification of the complex management issues related to patients with functional single ventricle physiology.

Younger age remains a risk factor for prolonged length of stay after bidirectional cavopulmonary anastomosis

OBJECTIVE

This study sets out to determine the influence of age at the time of surgery as a risk factor for post-operative length of stay after bidirectional cavopulmonary anastomosis.

METHODS

All patients undergoing a Glenn procedure between January 2010 and July 2015 were included in this retrospective cohort study. Demographic data were examined. Standard descriptive statistics was used. A univariable analysis was conducted using the appropriate test based on data distribution. A propensity score for balancing the group difference was included in the multi-variable analysis, which was then completed using predictors from the univariable analysis that achieved significance of p&lt;0.1.

RESULTS

Over the study period, 50 patients met the inclusion criteria. Patients were separated into two cohorts of ⩾4 months (28 patients) and &lt;4 months (22 patients). Other than height and weight, the two cohorts were indistinguishable in their pre-operative saturation, medications, catheterisation haemodynamics, atrioventricular valve regurgitation, and ventricular function. After adjusting group differences, younger age was associated with longer post-operative length of hospitalisation - adjusted mean 15 (±2.53) versus 8 (±2.15) days (p=0.03). In a multi-variable regression analysis, in addition to ventricular dysfunction (β coefficient=8.8, p=0.05), Glenn procedures performed before 4 months were independently associated with longer length of stay (β coefficient=-6.9, p=0.03).

CONCLUSION

We found that Glenn procedures performed after 4 months of age had shorter post-operative length of stay when compared to a younger cohort. These findings suggest that balancing timing of surgery to decrease the inter-stage period should take into consideration differences in post-operative recovery with earlier operations.

Early prediction of critical events for infants with single-ventricle physiology in critical care using routinely collected data

OBJECTIVE

Critical events are common and difficult to predict among infants with congenital heart disease and are associated with mortality and long-term sequelae. We aimed to achieve early prediction of critical events, that is, cardiopulmonary resuscitation, emergency endotracheal intubation, and extracorporeal membrane oxygenation in infants with single-ventricle physiology before second-stage surgery. We hypothesized that naïve Bayesian models learned from expert knowledge and clinical data can predict critical events early and accurately.

METHODS

We collected 93 patients with single-ventricle physiology admitted to intensive care units in a single tertiary pediatric hospital between 2014 and 2017. Using knowledge elicited from experienced cardiac-intensive-care-unit providers and machine-learning techniques, we developed and evaluated the Cardiac-intensive-care Warning INdex (C-WIN) system, consisting of a set of naïve Bayesian models that leverage routinely collected data. We evaluated predictive performance using the area under the receiver operating characteristic curve, sensitivity, and specificity. We performed the evaluation at 5 different prediction horizons: 1, 2, 4, 6, and 8 hours before the onset of critical events.

RESULTS

The area under the receiver operating characteristic curves of the C-WIN models ranged between 0.73 and 0.88 at different prediction horizons. At 1 hour before critical events, C-WIN was able to detect events with an area under the receiver operating characteristic curve of 0.88 (95% confidence interval, 0.84-0.92) and a sensitivity of 84% at the 81% specificity level.

CONCLUSIONS

Predictive models may enhance clinicians' ability to identify infants with single-ventricle physiology at high risk of critical events. Early prediction of critical events may indicate the need to perform timely interventions, potentially reducing morbidity, mortality, and health care costs.

Pathophysiology, adaptation, and imaging of the right ventricle in Fontan circulation

The Fontan procedure, which creates a total cavopulmonary anastomosis and represents the final stage of palliation for hypoplastic left heart syndrome, generates a unique circulation relying on a functionally single right ventricle (RV). The RV pumps blood in series around the systemic and pulmonary circulation, which requires adaptations to the abnormal volume and pressure loads. Here, we provide a complete review of RV adaptations as the RV assumes the role of the systemic ventricle, the progression of RV dysfunction to a distinct pattern of heart failure unique to this disease process, and the assessment and management strategies used to protect and rehabilitate the failing RV of Fontan circulation.