Outcomes After Hybrid Palliation for Infants With Critical Left Heart Obstruction

BACKGROUND

Hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) is an initial management strategy for infants with critical left heart obstruction and serves as palliation until subsequent operations are pursued.

OBJECTIVES

This study sought to determine patient characteristics and factors associated with subsequent outcomes for infants who underwent hybrid palliation.

METHODS

From 2005 to 2019, 214 of 1,236 prospectively enrolled infants within the Congenital Heart Surgeons' Society's critical left heart obstruction cohort underwent hybrid palliation across 24 institutions. Multivariable hazard modeling with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan procedure, transplantation, or death.

RESULTS

Preoperative comorbidities (eg, prematurity, low birth weight, genetic syndrome) were identified in 70% of infants (150 of 214). Median follow-up was 7 years, ranging up to 17 years. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had biventricular repair, 36% had Fontan procedure, 12% had transplantation, 35% died without surgical endpoints, and 8% were alive without an endpoint. Factors associated with transplantation were absence of ductal stent, older age, absent interatrial communication, smaller aortic root size, larger tricuspid valve area z-score, and larger left ventricular volume. Factors associated with death were low birth weight, concomitant genetic syndrome, cardiopulmonary bypass use during hybrid palliation, moderate to severe tricuspid valve regurgitation, and smaller ascending aortic size.

CONCLUSIONS

Mortality remains high after hybrid palliation for infants with critical left heart obstruction. Nonetheless, hybrid palliation may facilitate biventricular repair for some infants and for others may serve as stabilization for intended functional univentricular palliation or primary transplantation.

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.

Challenges in Accurate Diagnosis of HCC in FALD: A Case Series

Patients with single ventricle cardiac disease palliated with Fontan procedures inevitably develop Fontan-Associated Liver Disease (FALD), which poses a significant risk for hepatocellular carcinoma (HCC). Standard imaging criteria for the diagnosis of cirrhosis are not reliable due to parenchymal heterogeneity of FALD. We present 6 cases to demonstrate our center's experience and the challenges in diagnosing HCC within this patient population.

Effects of inhaled nitric oxide on Fontan hemodynamics in adults

The pulmonary vasculature plays a pivotal role in the nonpulsatile systemic venous return post-Fontan palliation. Elevated pulmonary vascular resistance index (PVRi) carries a worse prognosis post-Fontan, but the benefits of pulmonary vasodilators remain controversial. Moreover, the potential for worsening ventricular filling pressures with pulmonary vasodilation has been highlighted. We reviewed our experience with inhaled nitric oxide (iNO) administration during cardiac catheterization in 30 adults (age 32.7 ± 8.5 years) post-Fontan. The main findings of the study are: (1) iNO decreased pulmonary artery pressures, transpulmonary gradient, and PVRi without increasing pulmonary artery wedge pressure, (2) cardiac index was unchanged with iNO, and (3) different from acquired left heart disease, iNO did not result in further elevations in pulmonary artery wedge pressure in those with elevated ventricular filling pressures. iNO administration in adults post-Fontan was safe; whether baseline PVRi and response to iNO could be used to predict response to pulmonary vasodilators post-Fontan requires further investigation.

Clinical and invasively-measured predictors of high exercise capacity in Fontan patients

INTRODUCTION

Fontan patients have variable exercise capacity. Contemporary understanding as to which factors predict high tolerance is limited.

METHODS

Records from the Ahmanson/University of California, Los Angeles Adult Congenital Heart Disease Center were reviewed for adult Fontan patients who underwent CPET. Patients were considered "high performers" if their maximum oxygen uptake (VO2 max/kg)-predicted was greater than 80%. Cross-sectional clinical, hemodynamic, and liver biopsy data was gathered. High-performers were compared to control patients across these parameters via associations and regression.

RESULTS

A total of 195 adult patients were included; 27 patients were considered "high performers". They had lower body mass indices (BMI, p < 0.001), mean Fontan pressures (p = 0.026), and cardiac outputs (p = 0.013). High performers also had higher activity levels (p < 0.001), serum albumin levels (p = 0.003), non-invasive and invasive systemic arterial oxygen saturations (p < 0.001 and p = 0.004), lower New York Heart Association (NYHA) heart failure class (p = 0.002), and were younger at Fontan completion (p = 0.011). High performers had less severe liver fibrosis (p = 0.015). Simple regression found Fontan pressure, non-invasive O2 saturation, albumin level, activity level, age at Fontan surgery, NYHA class, and BMI to predict significant changes in VO2 max/kg %-predicted. These associations persisted in multiple regression for non-invasive O2 saturation, NYHA class II, activity level, and BMI.

CONCLUSIONS

Thin Fontan patients who exercise more had better exercise capacity, Fontan hemodynamic profiles, and less liver fibrosis.

Exercise capacity in the Danish Fontan population remains stable after ten years of follow-up - is physical activity the key to success?

BACKGROUND

Most Fontan patients have impaired exercise capacity, and a further decline in exercise capacity over time seems inevitable. However, few longitudinal studies exist, and there is a lack of data from newer eras. We aimed to describe the natural evolution of exercise capacity over a 10-year period in a contemporary, population-based cohort of Danish Fontan patients.

METHODS

The study was a nationwide, prospective study. A cardiopulmonary exercise test (CPET) was used to assess the exercise capacity. All Danish Fontan patients who participated in a national study in 2011 (CPET1), were invited to a follow-up visit in 2021 (CPET2). All patients who completed CPET1 and CPET2 with a respiratory exchange ratio over 1.0 were included. The main outcome was percent predicted VO2peak (%pred VO2peak). At the time of CPET2, patients filled out a questionnaire including questions regarding physical activity.

RESULTS

Seventy-seven patients completed both CPET1 and CPET2, and seventy patients completed the questionnaire. The time interval between the two CPETs was 10.4 ± 0.9 years. The median age was 15 years at CPET1 and 26 years at CPET2. The exercise capacity remained stable with a mean %pred VO2peak of 53.8 ± 11.3 at CPET1 and 55.6 ± 10.9 in CPET2 (p = 0.314). Higher levels of vigorous physical activity were associated with higher %pred VO2peak in CPET2 in a multivariate regression model.

CONCLUSION

The %pred VO2peak remained stable over a ten-year period in this population-based Fontan cohort. Higher levels of self-reported vigorous physical activity were associated with higher %pred VO2peak in the most recent CPET.

Influence of Respiration on Collateral Flow in the Fontan Population Using Real-time Phase-contrast Cardiovascular Magnetic Resonance: Collateral Flow Does Not Protect the Ventricle From Volume Deficiency and Diastolic Dysfunction

PURPOSE

The clinical significance of collateral flow for the ventricular function of patients with univentricular hearts is often debated. This study evaluates the impact of collateral flow on respiration-dependent preload modification and diastolic function in Fontan patients assessed by systemic and pulmonary vein (PV) flow patterns.

MATERIALS AND METHODS

Real-time phase-contrast cardiovascular magnetic resonance was performed in the right upper PV, ascending aorta, superior, and inferior vena cava (IVC) in 21 Fontan patients and 11 healthy individuals. The patients' respiratory cycle was divided into 4 periods to generate respiratory-dependent stroke volumes (SV i ). Conventional quantitative blood flow measurements were used to quantify and differentiate between low (group A) and high (group B) collateral flow.

RESULTS

Group B showed significantly lower SV i IVC in inspiration, end-inspiration, expiration, and SV i ΔIVC compared with group A (23.6±4.8 mL/m 2 to 33.4±8.0; P =0.005). PV flow resulted in a lower mean SV i PV (11.6±7.6 mL/m 2 , vs. 14.0±11.4 mL/m 2 ) as well as a significantly lower peak systolic S-wave velocity (S max ) ( P =0.005), S/D-ratio (S max /peak diastolic wave velocity) ( P =0.015), and shorter diastolic deceleration time (DT D ; P =0.030; median DT D =134 ms) compared with group A (DT D =202 ms).

CONCLUSIONS

This study demonstrates the incapability of Fontan patients to properly increase preload by inspiration in the presence of significant collateral flow. The results further show that collateral flow is associated with a volume-deprived ventricle and impaired diastolic function.

Contemporary risk factors for a longer hospital stay following bidirectional cavopulmonary anastomosis

BACKGROUND

Despite high survival after bidirectional cavopulmonary anastomosis, a considerable number of patients suffer significant post-operative morbidities related to prolonged length of stay.

METHODS

A single-center retrospective cohort study of all consecutive patients undergoing a first-time bidirectional cavopulmonary anastomosis from 2006 to 2019.

RESULTS

Prolonged length of stay was defined as hospital stay greater than the 75th percentile for our cohort. Of 195 patients who met inclusion criteria, the median post-operative length of stay was 8 days (interquartile range, 4-15 days). Prolonged length of stay was defined as greater than 15 days. In multivariate analysis, greater than mild systemic atrioventricular valve regurgitation (odds ratio 3.7, 95% CI 1.05-13.068, p = 0.04), longer length of stay after the initial palliative procedure (odds ratio 1.028, 95% CI 1.004-1.05, p = 0.02), and pre-operative higher superior vena cava oxygen saturation (odds ratio 0.922, 95% CI 0.85-0.99, p = 0.04) maintained statistical significance as independent risk and protective factors for prolonged length of stay. A one-level increase in the severity of pre-operative systemic atrioventricular valve regurgitation was associated with a multiplicative change in the odds ratio of prolonged length of stay of 5.45 (p = 0.005) independent of the severity of systemic ventricular dysfunction.

CONCLUSION

Pre-operative characteristics with greater than mild systemic atrioventricular valve regurgitation, longer length of stay after the initial palliative procedure, and lower superior vena cava oxygen saturation were associated with prolonged length of stay after a first-time bidirectional cavopulmonary anastomosis.

Current practice of care for adolescent and adult patients after Fontan surgery in Poland

BACKGROUND

The growing number of adult patients after the Fontan operation requires regular surveillance tests in specialized centers.

AIMS

Our study aimed to evaluate the current practice of care for Fontan patients in Poland using a multicenter survey.

METHODS

Eight centers were included in the study including 5 adult congenital heart disease (ACHD) and 3 pediatric centers for adolescents. To compare the centers and facilitate interpretation of results, the Fontan Surveillance Score (FSS) was developed. The higher score is consistent with better care, with a maximum of 19 points.

RESULTS

We included in the study 398 Fontan patients (243 adults and 155 adolescents [aged 14-18 years]). The median FSS was 13 points with variability between centers (interquartile range 7-14 points). Centers providing continuous care from the pediatric period until 18 years of age achieved a higher FSS compared to ACHD centers (median: 14 points vs. 12 points; P <0.001). Most of the patients, both in the ACHD (82.3%) and pediatric centers (89%), were seen annually and had a physical examination, electrocardiogram, and echocardiogram performed at each visit. However, we observed unsatisfactory utilization of tests identifying early stages of Fontan circulation failure (cardiopulmonary exercise tests, cardiac magnetic resonance, liver biochemistry and imaging, detection of protein-losing enteropathy).

CONCLUSIONS

Our results showed that there is no unified surveillance approach for Fontan patients in Poland. The practice of care for adults differs from that of adolescents.

Assessment of liver fibrosis using a 3-dimensional high-resolution late gadolinium enhancement sequence in children and adolescents with Fontan circulation

OBJECTIVES

To assess abnormal liver enhancement on 15-20 min delayed 3D high-resolution late gadolinium enhancement (3D HR LGE) sequence in patients with Fontan circulation.

METHODS

Retrospective study of pediatric Fontan patients (< 18 years old) with combined cardiac-liver MRI from January 2018 to August 2021. Abnormal hepatic enhancement was graded (0-3) for each lobe, summed for a total liver enhancement score (0-6), and compared to repaired tetralogy of Fallot (rTOF) patients. Correlations with other hepatic imaging biomarkers were performed. Temporal relationships of enhancement compared to traditional early portal venous and 5-7-min delayed phase liver imaging were analyzed.

RESULTS

The Fontan group (n = 35, 13 ± 3.4 years old, median time from Fontan 10 (9-12) years) had 23/35 (66%) with delayed 3D HR LGE total liver enhancement score > 0 (range 0-5), with greater involvement of the right lobe (1 (0-1) vs 0 (0-1), p < 0.01). The rTOF group (n = 35, 14 ± 2.6 years old) had no abnormal enhancement. In the Fontan group, total liver enhancement was 3 (2-4) in the early portal venous phase, lower at 1 (1-2) in the 5-7-min delayed phase (p < 0.01), and lowest at 1 (0-2) in the 15-20-min delayed phase (p = 0.03). 3D HR LGE enhancement correlated inversely with portal vein flow (rs =  - 0.42, p = 0.01) and positively with left lobe stiffness (rs = 0.51, p < 0.01). The enhancement score decreased in 13/35 (37%) between the 5-7- and 15-20-min delayed phases.

CONCLUSIONS

Liver fibrosis can be assessed on 3D HR LGE sequences in patients with Fontan circulation, correlates with other imaging biomarkers of Fontan liver disease, and may add information for hepatic surveillance in this population.

KEY POINTS

• Abnormal liver enhancement on 3D HR LGE sequences in Fontan patients likely represents liver fibrosis and is seen in up to 66% of children and adolescents with variable distribution and severity. • The degree of 3D HR LGE liver enhancement correlates with decreased portal vein flow and increased left hepatic lobe stiffness.

Feasibility of an Animal Model for Cavopulmonary Support With a Double-Outflow Pump

Both single- and double-outflow cavopulmonary assist devices (CPADs) were recently proposed for the Fontan population, whereas single-outflow configurations were evaluated in large animal trials and double-outflow concepts are lacking an equivalent in vivo assessment. The aim of this study was to test the hemodynamic properties of a double-outflow CPAD device in an acute sheep model. The two inflow cannulae of a CPAD were anastomosed to the caval veins. Outflow graft connection was performed via end-to-side anastomosis to the right (RPA) and main pulmonary artery (MPA). Speed ramp protocols were conducted, and hemodynamic effects were monitored in terms of caval flows, cardiac output (CO), central venous pressure (CVP), pulmonary artery pressure (PAP), and left atrial pressure (LAP). Six experiments were conducted (53.35 ± 5.1 kg). In three experiments, the animal model was established, the CPAD was examined, and restoration of biventricular equivalency in terms of venous return was achieved. Venous pressures (CVP) declined linearly with increasing pump speed (r > 0.879), whereas caval flow (r > 0.973), CO (r > 0.993), PAP (r > 0.973), and LAP (r > 0.408) increased. Despite the considerable complexity of the sheep model caused by the sheep pulmonary arterial anatomy that requires substantial graft bending, the CPAD was evaluated in three acute experiments and showed the potential to completely substitute a subpulmonary ventricle.

Common arterial trunk in functionally univentricular hearts: a case series

INTRODUCTION

The association of a univentricular heart defect with common arterial trunk is extremely rare. There is a lack of population-based outcome studies reported in the literature.

METHODS

The hospital records, echocardiographic and other imaging modality data, outpatients' records, operation notes, and other electronic data were reviewed. Patients were reviewed, and the final outcomes of surgery were observed.

RESULTS

Six cases (two males) with common arterial trunk presented over a 30-year period. Five had a complete unbalanced atrioventricular septal defect (83%) and one (17%) had tricuspid atresia associated with common arterial trunk. All had antenatal diagnosis. Two cases (33%) were excluded from initial surgical palliation due to Trisomy 21 in one and severe truncal valve regurgitation in one. Initial surgical palliation was performed in four cases (67%) at median age of 31 days (2-60) and consisted of disconnection and reconstruction of the pulmonary arteries and establishing controlled pulmonary blood flow. There were no early deaths. Conversion to cavopulmonary shunt was not possible in two due to severe airway problems in one and pulmonary arteries anatomy in one. They died at 11 and 16 months, respectively. Two patients (33%) underwent cavopulmonary shunt with 1 (17%) being alive at 18 months - 12 months after cavopulmonary shunt. The second patient proceeded to Fontan completion at 19 months but required catheter takedown 3 months later and died 3.5 years later.

CONCLUSIONS

Univentricular hearts with common arterial trunk carry extremely poor short- to medium-term outcomes. This should inform antenatal and postnatal counselling and decision-making.

Design and rationale of re-energize fontan: Randomized exercise intervention designed to maximize fitness in fontan patients

In this manuscript, we describe the design and rationale of a randomized controlled trial in pediatric Fontan patients to test the hypothesis that a live-video-supervised exercise (aerobic+resistance) intervention will improve cardiac and physical capacity; muscle mass, strength, and function; and endothelial function. Survival of children with single ventricles beyond the neonatal period has increased dramatically with the staged Fontan palliation. Yet, long-term morbidity remains high. By age 40, 50% of Fontan patients will have died or undergone heart transplantation. Factors that contribute to onset and progression of heart failure in Fontan patients remain incompletely understood. However, it is established that Fontan patients have poor exercise capacity which is associated with a greater risk of morbidity and mortality. Furthermore, decreased muscle mass, abnormal muscle function, and endothelial dysfunction in this patient population is known to contribute to disease progression. In adult patients with 2 ventricles and heart failure, reduced exercise capacity, muscle mass, and muscle strength are powerful predictors of poor outcomes, and exercise interventions can not only improve exercise capacity and muscle mass, but also reverse endothelial dysfunction. Despite these known benefits of exercise, pediatric Fontan patients do not exercise routinely due to their chronic condition, perceived restrictions to exercise, and parental overprotection. Limited exercise interventions in children with congenital heart disease have demonstrated that exercise is safe and effective; however, these studies have been conducted in small, heterogeneous groups, and most had few Fontan patients. Critically, adherence is a major limitation in pediatric exercise interventions delivered on-site, with adherence rates as low as 10%, due to distance from site, transportation difficulties, and missed school or workdays. To overcome these challenges, we utilize live-video conferencing to deliver the supervised exercise sessions. Our multidisciplinary team of experts will assess the effectiveness of a live-video-supervised exercise intervention, rigorously designed to maximize adherence, and improve key and novel measures of health in pediatric Fontan patients associated with poor long-term outcomes. Our ultimate goal is the translation of this model to clinical application as an "exercise prescription" to intervene early in pediatric Fontan patients and decrease long-term morbidity and mortality.

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.