Long-term survival, modes of death, and predictors of mortality in patients with Fontan surgery

Meta-analysis: Incidence of cirrhosis and hepatocellular carcinoma in patients with Fontan palliation

BACKGROUND AND AIMS

The Fontan palliation is the final stage of surgery for many children born with univentricular physiology. Almost all Fontan patients develop liver fibrosis which may eventually lead to cirrhosis and hepatocellular carcinoma (HCC). These are important causes of morbidity and mortality in these patients. We performed a systematic review and meta-analysis to assess the incidence of cirrhosis and HCC in Fontan patients and stratify it based on time since surgery.

METHODS

A literature search of seven databases identified 1158 records. Studies reporting the number of cirrhosis and HCC cases in Fontan patients and time since Fontan surgery were included. In the cirrhosis cohort, we included only those studies where all patients underwent liver biopsy.

RESULTS

A total of 23 studies were included: 12 and 13 studies in the cirrhosis and HCC cohorts, respectively, with two studies included in both cohorts. The incidence of cirrhosis was 0.97 per 100 patient-years (95% CI 0.57-1.63), with the incidence and cumulative incidence ≥20 years post Fontan surgery being 1.61 per 100 patient-years (95% CI 1.24-2.08) and 32.2% (95% CI 25.8%-39.4%), respectively. The incidence of HCC was 0.12 per 100 patient-years (95% CI 0.07-0.21), with the incidence and cumulative incidence ≥20 years post Fontan surgery being 0.20 per 100 patient-years (95% CI 0.12-0.35) and 3.9% (95% CI 2.2%-6.8%), respectively. Only about 70% of patients with HCC (20/28) had underlying cirrhosis.

CONCLUSION

The incidence of cirrhosis and HCC increases over time, especially at ≥20 years post Fontan surgery. Studies are needed to further identify at-risk patients in order to streamline surveillance for these highly morbid conditions.

Effect of patient factors, center, and era on Fontan timing: An observational study using the Pediatric Health Information Systems Database

BACKGROUND

There are no consensus guidelines defining optimal timing for the Fontan operation, the last planned surgery in staged palliation for single-ventricle heart disease.

OBJECTIVES

Identify patient-level characteristics, center-level variation, and secular trends driving Fontan timing.

METHODS

A retrospective observational study of subjects who underwent Fontan from 2007 to 2021 at centers in the Pediatric Health Information Systems database was performed using linear mixed-effects modeling in which age at Fontan was regressed on patient characteristics and date of operation with center as random effect.

RESULTS

We included 10,305 subjects (40.4% female, 44% non-white) at 47 centers. Median age at Fontan was 3.4 years (IQR 2.6-4.4). Hypoplastic left heart syndrome (-4.4 months, 95%CI -5.5 to -3.3) and concomitant conditions (-2.6 months, 95%CI -4.1 to -1.1) were associated with younger age at Fontan. Subjects with technology-dependence (+4.6 months, 95%CI 3.1-6.1) were older at Fontan. Black (+4.1 months, 95%CI 2.5-5.7) and Asian (+8.3 months, 95%CI 5.4-11.2) race were associated with older age at Fontan. There was significant variation in Fontan timing between centers. Center accounted for 10% of variation (ICC 0.10, 95%CI 0.07-0.14). Center surgical volume was not associated with Fontan timing (P = .21). Operation year was associated with age at Fontan, with a 3.1 month increase in age for every 5 years (+0.61 months, 95%CI 0.48-0.75).

CONCLUSIONS

After adjusting for patient-level characteristics there remains significant inter-center variation in Fontan timing. Age at Fontan has increased. Future studies addressing optimal Fontan timing are warranted.

Association of patient-level characteristics with long-term outcomes after Fontan palliation: Rationale, design, and baseline characteristics of the Pediatric Cardiac Care Consortium Fontan cohort study

BACKGROUND

The Fontan operation is used to palliate single ventricle congenital heart defects (CHD) but poses significant morbidity and mortality risks. We present the design, planned analyses, and rationale for a long-term Fontan cohort study aiming to examine the association of patient characteristics at the time of Fontan with post-Fontan morbidity and mortality.

METHODS AND RESULTS

We used the Pediatric Cardiac Care Consortium (PCCC), a US-based, multicenter registry of pediatric cardiac surgeries to identify patients who underwent the Fontan procedure for single ventricle CHD between 1 and 21 years of age. The primary outcomes are in-hospital Fontan failure (death or takedown) and post-discharge mortality through 2022. A total of 1461 (males 62.1%) patients met eligibility criteria and were included in the analytical cohort. The median age at Fontan evaluation was 3.1 years (IQR: 2.4-4.3). While 95 patients experienced in-hospital Fontan failure (78 deaths and 17 Fontan takedown), 1366 (93.5%) survived to discharge with Fontan physiology and formed the long-term analysis cohort. Over a median follow-up of 21.2 years (IQR: 18.4-24.5) 184 post-discharge deaths occurred. Thirty-year post Fontan survival was 75.0% (95% CI: 72.3%-77.8%) for all Fontan types with higher rates for current techniques such as lateral tunnel and extracardiac conduit 77.1% (95% CI: 73.5-80.8).

CONCLUSION

The PCCC Fontan study aims to identify predictors for post-Fontan morbidity and mortality, enabling risk- stratification and informing surveillance practices. Additionally, the study may guide therapeutic interventions aiming to optimize hemodynamics and enhance Fontan longevity for individual patients.

Tachyarrhythmia after the total cavopulmonary connection: incidence, prognosis, and risk factors

OBJECTIVE

The purpose of this study is to evaluate the incidence and outcomes regarding tachyarrhythmia in patients after total cavopulmonary connection.

METHODS

A retrospective analysis of 620 patients who underwent total cavopulmonary connection between 1994 and 2021 at our institution was performed. Incidence of tachyarrhythmia was depicted, and results after onset of tachyarrhythmia were evaluated. Factors associated with the onset of tachyarrhythmia were identified.

RESULTS

A total of 52 (8%) patients presented with tachyarrhythmia that required medical therapy. Onset during hospital stay was observed in 27 patients, and onset after hospital discharge was observed in 32 patients. Freedom from late tachyarrhythmia following total cavopulmonary connection at 5, 10, and 15 years was 97, 95, and 91%, respectively. The most prevalent late tachyarrhythmia was atrial flutter (50%), followed by supraventricular tachycardia (25%) and ventricular tachycardia (25%). Direct current cardioversion was required in 12 patients, and 7 patients underwent electrophysiological study. Freedom from Fontan circulatory failure after onset of tachyarrhythmia at 10 and 15 years was 78% and 49%, respectively. Freedom from occurrence of decreased ventricular systolic function after the onset of tachyarrhythmia at 5 years was 85%. Independent factors associated with late tachyarrhythmia were dominant right ventricle (hazard ratio, 2.52, p = 0.02) and weight at total cavopulmonary connection (hazard ratio, 1.03 per kilogram; p = 0.04). Type of total cavopulmonary connection at total cavopulmonary connection was not identified as risk.

CONCLUSIONS

In our large cohort of 620 patients following total cavopulmonary connection, the incidence of late tachyarrhythmia was low. Patients with dominant right ventricle and late total cavopulmonary connection were at increased risk for late tachyarrhythmia following total cavopulmonary connection.

Decreased erythrocyte aggregation in Glenn and Fontan: univentricular circulation as a rheologic disease model

BACKGROUND

In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation.

METHODS

We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences.

RESULTS

Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation.

CONCLUSIONS

Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss.

IMPACT

Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.

Study on the optimal elastic modulus of flexible blades for right heart assist device supporting patients with single-ventricle physiologies

Background

Patients with single-ventricle physiologies continue to experience insufficient circulatory power after undergoing palliative surgeries. This paper proposed a right heart assist device equipped with flexible blades to provide circulatory assistance for these patients. The optimal elastic modulus of the flexible blades was investigated through numerical simulation.

Methods

A one-way fluid-structure interaction (FSI) simulation was employed to study the deformation of flexible blades during rotation and its impact on device performance. The process began with a computational fluid dynamics (CFD) simulation to calculate the blood pressure rise and the pressure on the blades' surface. Subsequently, these pressure data were exported for finite element analysis (FEA) to compute the deformation of the blades. The fluid domain was then recreated based on the deformed blades' shape. Iterative CFD and FEA simulations were performed until both the blood pressure rise and the blades' shape stabilized. The blood pressure rise, hemolysis risk, and thrombosis risk corresponding to blades with different elastic moduli were exhaustively evaluated to determine the optimal elastic modulus.

Results

Except for the case at 8,000 rpm with a blade elastic modulus of 40 MPa, the pressure rise associated with flexible blades within the studied range (rotational speeds of 4,000 rpm and 8,000 rpm, elastic modulus between 10 MPa and 200 MPa) was lower than that of rigid blades. It was observed that the pressure rise corresponding to flexible blades increased as the elastic modulus increased. Additionally, no significant difference was found in the hemolysis risk and thrombus risk between flexible blades of various elastic moduli and rigid blades.

Conclusion

Except for one specific case, deformation of the flexible blades within the studied range led to a decrease in the impeller's functionality. Notably, rotational speed had a more significant impact on hemolysis risk and thrombus risk compared to blade deformation. After a comprehensive analysis of blade compressibility, blood pressure rise, hemolysis risk, and thrombus risk, the optimal elastic modulus for the flexible blades was determined to be between 40 MPa and 50 MPa.

Long-Term Survival After Single-Ventricle Palliation: A Swedish Nationwide Cohort Study

BACKGROUND

Long-term survival after single-ventricle palliation and the effect of dominant ventricle morphology in large, unselected series of patients are scarcely reported.

METHODS AND RESULTS

This nationwide cohort study included all children undergoing operation with single-ventricle palliation during their first year of life in Sweden between January 1994 and December 2019. Data were obtained from institutional records and assessment of underlying cardiac anomaly and dominant ventricular morphology was based on complete review of medical records, surgical reports, and echocardiographic examinations. Data on vital status and date of death were retrieved from the Swedish Cause of Death Register, allowing for complete data on survival. Among 766 included patients, 333 patients (43.5%) were classified as having left or biventricular dominance, and 432 patients (56.4%) as having right ventricular (RV) dominance (of whom 231 patients had hypoplastic left heart syndrome). Follow-up was 98.7% complete (10 patients emigrated). Mean follow-up was 11.3 years (maximum, 26.7 years). Long-term survival was significantly higher in patients with left ventricular compared with RV dominance (10-year survival: 91.0% [95% CI, 87.3%-93.6%] versus 71.1% [95% CI, 66.4%-75.2%]). RV dominance had a significant impact on outcomes after first-stage palliation but was also associated with impaired survival after completed total cavopulmonary connection. In total, 34 (4.4%) patients underwent heart transplantation. Of these 34 patients, 25 (73.5%) had predominant RV morphology.

CONCLUSIONS

This study provides clinically relevant knowledge about the long-term prognosis in patients with different underlying cardiac anomalies undergoing single-ventricle palliation. RV dominance had a significant impact on outcomes after initial surgical treatment but was also associated with impaired survival after completed Fontan circulation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03356574.

Relationship Between Obesity and Global Longitudinal Strain in the Pediatric Single Ventricle Fontan Population Across Ventricular Morphologies

BACKGROUND

Obesity is associated with diminished myocardial function as measured by strain echocardiography in children and young adults with normal cardiac anatomy. Data are lacking about the effect of obesity on myocardial strain in patients with a single ventricle. In this study, the relationship between body mass index (BMI) and single ventricle myocardial strain in the Fontan population was assessed.

METHODS AND RESULTS

Thirty-eight abnormal BMI Fontan cases (21 overweight and 17 obese) and 30 normal BMI Fontan controls matched based on single ventricular morphology, age, and sex were included in the study. Ventricular morphology was categorized as single right ventricle, single left ventricle, or biventricular. Single ventricle global longitudinal peak systolic strain (GLS) and other echocardiographic measurements were performed and compared between groups, with a P≤0.05 defined as significant. The abnormal BMI group demonstrated diminished GLS (-15.7±3.6% versus -17.2±3.2%, [P=0.03]) and elevated systolic blood pressure (P=0.04) compared with the normal BMI group. On subgroup analysis of those with single right ventricle morphology, the abnormal BMI group demonstrated diminished GLS compared with controls. There was no significant difference in GLS between the abnormal BMI and control groups in the single left ventricle and biventricular subgroups. Analyzed by ventricular morphology, no other variables were statistically different in the abnormal BMI group including systolic blood pressure. Inter-reader reproducibility for GLS and strain rate were excellent for both measures.

CONCLUSIONS

Obesity has an adverse relationship with myocardial strain in the young Fontan population, with the most maladaptive response seen in the single right ventricle.

Morbidity and mortality in adults with a Fontan circulation beyond the fourth decade of life

AIMS

To evaluate the late outcomes of adults (above 35 years) with a Fontan-type circulation, for whom current data on morbidity and mortality are lacking.

METHODS AND RESULTS

Data were collected retrospectively on consecutive patients with Fontan circulation above the age of 35 years followed in three European specialist centres. Overall, 115 Fontan patients were included [median age 35 (range 35-48) years, 47.8% female]. The most common underlying congenital heart disease diagnosis was tricuspid atresia (n = 58, 50.4%), and the age at first Fontan completion was 9.1 (interquartile range 5.0-15.8) years. Almost two-thirds (61.7%) of patients had undergone an atriopulmonary Fontan, and 23.5% had received a total cavopulmonary connection. One-third required repeat surgery or intervention. Most patients (55.9%) were in New York Heart Association functional class II or class I (30.6%), 76 (66.1%) patients had experienced at least one arrhythmia, and eight (7.0%) protein-losing enteropathy. At a median follow-up of 5.0 (2.4-10.3) years, 15 (13.0%) patients were referred for transplantation assessment and 19 (16.5%) patients died, mainly from heart failure (84.2%). Univariable predictors of death or transplantation included lower serum albumin level [hazard ratio (HR) 1.09 per g/L decrease, 95% confidence interval (CI): 1.04-1.15, P = 0.0009], prior heart failure admission (HR 4.28, 95% CI:1.75-10.44, P = 0.001), prior atrial tachycardia or flutter (HR 3.02, 95% CI: 1.23-7.38, P = 0.02), and baseline pulmonary vasodilator therapy (HR 8.59, 95% CI:1.05-70.13, P = 0.04). Lower serum albumin and prior atrial tachycardia or flutter remained significant on bivariable analysis.

CONCLUSION

Our study highlights the significant morbidity and mortality in older adults with a Fontan-type circulation, emphasizing the need for lifelong specialist surveillance with frequent risk stratification, close monitoring, and early consideration for transplantation assessment.

Francis Fontan (1929-2018): Pioneer pediatric cardiac surgeon

Up until the mid-1900s, tricuspid atresia - a birth defect of the tricuspid valve, was once categorized as a "death sentence." The challenge of achieving positive health outcomes for affected patients was compounded by a hesitancy to operate on children. The main concern was safely administering anesthesia to young patients who were going through a strenuous operation that was often poorly tolerated. Despite these assumed limitations, Francis Fontan, a pediatric cardiothoracic surgeon at the Hospital of Tondu in Bordeaux, was able to redirect blood flow from the superior and inferior vena cava to the pulmonary arteries in 1971, which elucidated the process of advancing clinical practice in medicine. With the support of mentors and a firm belief in this new technique, Fontan pioneered his eponymous procedure and ultimately paved the way for modern cardiovascular surgical techniques that helped to prolong the life of those with single functioning ventricles. The aim of this study is to examine the genesis and the evolution of the Fontan procedure to elucidate the process of advancing clinical practice in medicine by utilizing personal interviews, Fontan's works, associated primary and secondary sources in the context of 20th century cardiothoracic surgery and innovations.

Impact of Fontan Fenestration on Adverse Cardiovascular Outcomes: A Multicentre Study

BACKGROUND

Fenestrating a Fontan baffle has been associated with improved perioperative outcomes in patients with univentricular hearts. However, longer-term potential adverse effects remain debated. We sought to assess the impact of a fenestrated Fontan baffle on adverse cardiovascular events including all-cause mortality, cardiac transplantation, atrial arrhythmias, and thromboemboli.

METHODS

A multicentre North American retrospective cohort study was conducted on patients with total cavopulmonary connection Fontan baffle, with and without fenestration. All components of the composite outcome were independently adjudicated. Potential static and time-varying confounders were taken into consideration, along with competing risks.

RESULTS

A total of 407 patients were followed for 10.4 (7.1-14.4) years; 70.0% had fenestration of their Fontan baffle. The fenestration spontaneously closed or was deliberately sealed in 79.9% of patients a median of 2.0 years after Fontan completion. In multivariable analysis in which a persistent fenestration was modelled as a time-dependent variable, an open fenestration did not confer a higher risk of the composite outcome (hazard ratio, 1.18; 95% confidence interval, 0.71-1.97; P = 0.521). In secondary analyses, an open fenestration was not significantly associated with components of the primary outcome: that is, mortality or transplantation, atrial arrhythmias, or thromboemboli. However, sensitivity analyses to assess the possible range of error resulting from imprecise dates for spontaneous fenestration closures could not rule out significant associations between an open fenestration and atrial arrhythmias or thromboemboli.

CONCLUSIONS

In this multicentre study, no significant association was identified between an open fenestration in the Fontan baffle and major adverse cardiovascular events.

Nutritional considerations for people living with a Fontan circulation: a narrative review

The population of people living with a Fontan circulation are highly heterogenous, including both children and adults, who have complex health issues and comorbidities associated with their unique physiology throughout life. Research focused on nutritional considerations and interventions in the Fontan population is extremely limited beyond childhood. This review article discusses the current literature examining nutritional considerations in the setting of Fontan physiology and provides an overview of the available evidence to support nutritional management strategies and future research directions. Protein-losing enteropathy, growth deficits, bone mineral loss, and malabsorption are well-recognised nutritional concerns within this population, but increased adiposity, altered glucose metabolism, and skeletal muscle deficiency are also more recently identified issues. Emergencing evidence suggets that abnormal body composition is associated with poor circulatory function and health outcomes. Many nutrition-related issues, including the impact of congenital heart disease on nutritional status, factors contributing to altered body composition and comorbidities, as well as the role of the microbiome and metabolomics, remain poodly understood.

Detection of hepatocellular carcinoma during Fontan-associated liver disease follow-up: a report of three cases

We herein demonstrate three patients diagnosed with early hepatocellular carcinoma (HCC) during follow-up for Fontan-associated liver disease (FALD). Case 1: Twenty-one years after undergoing the Fontan procedure, a 26-year-old female was diagnosed with FALD. At the initial consultation, her serum alpha-fetoprotein (AFP) levels were markedly elevated, and dynamic enhanced computed tomography (CT) revealed HCC measuring 40 mm in diameter. She underwent partial hepatectomy. Ten months later, she underwent conventional transcatheter arterial chemoembolization (cTACE) for recurrent HCC near the resected hepatic stump as a curative treatment. Case 2: Twenty-one years after undergoing the Fontan procedure, a 25-year-old male was diagnosed with FALD and underwent HCC surveillance every 6 months. Thirteen months after the initial consultation, dynamic enhanced CT revealed HCC measuring 10 mm in diameter. He received cTACE as a curative treatment. Case 3. Twenty-eight years after undergoing the Fontan procedure, a 37-year-old male was diagnosed with FALD and underwent HCC surveillance every 3 months. Fourteen months later, abdominal ultrasonography (US) revealed HCC measuring 13 mm in diameter. He received radiofrequency ablation. These cases showed that HCC surveillance using abdominal US and AFP measurements in patients with FALD enables the detection of HCC and increases the chance of a cure.

Biomarkers of fibrosis and portal hypertension in Fontan-associated liver disease in children and adults

BACKGROUND

Fontan-associated liver disease (FALD) refers to structural and functional changes of the liver caused by the physiology of the Fontan palliation. Currently, liver biopsy is the gold standard to assess liver fibrosis of FALD.

AIM

Investigate biomarkers correlating with severity of liver biopsy fibrosis in FALD.

METHODS

A retrospective study of post-Fontan patients ≥ 10 years of age who underwent liver biopsy was conducted. Advanced liver disease (ALD) was defined as bridging fibrosis and/or cirrhosis on liver biopsy. AST-to-platelet ratio index (APRI), Fibrosis-4 (FIB-4) and Liver Stiffness Measurement (LSM) from FibroScan were used as non-invasive fibrosis scores.

RESULTS

Sixty-six patients (26/47; 55.3% adults and 13/19 children; 68.4%) had ALD on biopsy. ALD was associated with lower platelet count (151 vs. 198 K/uL, p = 0.003), higher APRI (0.64 vs. 0.32, p = 0.01), higher FIB-4 (0.64 vs. 0.32, p = 0.02). Liver fibrosis score correlated with APRI (0.34, p = 0.02) and FIB-4 (0.47, p = 0.001) in adults. LSM had a high sensitivity at 81.3% with 45.5% specificity at a cut-off 18.5 kPa.

CONCLUSIONS

APRI and FIB-4 had modest discrimination to identify adults with advanced liver disease, but not children, indicating that these values may be followed as a marker of FALD progression in older patients.

In vitro investigation of axial mechanical support devices implanted in the novel convergent cavopulmonary connection Fontan

OBJECTIVES

The 2 opposing inflows and 2 outflows in a total cavopulmonary connection make mechanical circulatory support (MCS) extremely challenging. We have previously reported a novel convergent cavopulmonary connection (CCPC) Fontan design that improves baseline characteristics and provides a single inflow and outflow, thus simplifying MCS. This study aims to assess the feasibility of MCS of this novel configuration using axial flow pumps in an in vitro benchtop model.

METHODS

Three-dimensional segmentations of 12 single-ventricle patients (body surface area 0.5-1.75 m2) were generated from cardiovascular magnetic resonance images. The CCPC models were designed by connecting the inferior vena cava and superior vena cava to a shared conduit ascending to the pulmonary arteries, optimized in silico. The 12 total cavopulmonary connection and their corresponding CCPC models underwent in vitro benchtop characterization. Two MCS devices were used, the Impella RP® and the PediPump.

RESULTS

MCS successfully and symmetrically reduced the pressure in both vena cavae by >20 mmHg. The devices improved the hepatic flow distribution balance of all CCPC models (Impella RP®P = 0.045, PediPump P = 0.055).

CONCLUSIONS

The CCPC Fontan design provides a feasible MCS solution for a failing Fontan by balancing hepatic flow distribution and symmetrically decompressing the central venous pressure. Cardiac index may also improve with MCS. Additional studies are needed to evaluate this concept for managing Fontan failure.

Congenital Heart Disease in the Adult Cardiac Intensive Care Unit

This article provides a broad overview of key concepts and more commonly encountered critical illness presentations in adult congenital heart disease (ACHD) patients. General principles are discussed, and the need for ACHD subspecialty consultation is emphasized. ACHD is categorized based on hemodynamic profile, and common clinical presentations are reviewed, including common pitfalls. Many ACHD lesions are associated with predictable complications, and awareness of these associations can guide evaluation and management, which are listed in this article.

Early Experience and Lessons Learned Using Implanted Hemodynamic Monitoring in Patients With Fontan Circulation

BACKGROUND

Data on the use of implanted hemodynamic monitoring (IHM) in patients with Fontan circulation are limited. This study reports our experience using the CardioMEMS HF system in adults with Fontan circulation.

METHODS AND RESULTS

This single-center, retrospective study evaluated heart failure hospitalizations, procedural complications, and device-related complications in patients with Fontan circulation referred for IHM placement (2015-2022). The association of pulmonary artery pressure (by most recent catheterization and median IHM pressure within 30 days of placement) with both death and follow-up Model for End-Stage Liver Disease Excluding International Normalized Ratio score were evaluated. Of 18 patients referred for IHM placement, 17 were successful (median age, 30 [range 21-48] years, 6 women). Procedural complications (access site hematomas, pulmonary artery staining) occurred in 3 patients, without device-related procedural complications. In follow-up (median, 35 [range, 6-83] months), 1 patient developed a pulmonary embolism (possibly device-related). Heart failure hospitalizations/year were similar before and after IHM (median, 1 [interquartile range, 0-1.0] versus 0.6 [0-2.3]; P=0.268), though only 46% of heart failure hospitalizations had associated IHM transmissions. IHM pressures were associated with Model for End-Stage Liver Disease Excluding International Normalized Ratio scores (R2=0.588, P<0.001), though catheterization pressures were not (R2=0.140, P=0.139). The long-term mortality rate was 53% in this cohort. On unadjusted survival analysis, IHM pressures ≥18 mm Hg were associated with mortality (log rank P=0.041), which was not reproduced with catheterization pressures (log rank P=0.764).

CONCLUSIONS

In patients with Fontan circulation, IHM did not reduce heart failure hospitalizations, though patient adherence to transmission was low. Device-related complications were low. IHM pressures may better represent real-life conditions compared with catheterization given associations with mortality and Model for End-Stage Liver Disease Excluding International Normalized Ratio score.

Heart transplantation surgery in children and young adults with congenital heart disease

BACKGROUND

Pediatric cardiac transplantation remains a surgical challenge as a variety of cardiac and vessel malformation are present in patients with congenital heart disease (CHD). Despite limited availability and acceptability of donor hearts, the number of heart transplantations remains on a stable level with improved survival and quality of life.

OBSERVATION

As treatment options for CHD continue to improve and the chances of survival increase, more adult CHD patients are listed for transplantation. This review focuses on the clinical challenges and modified techniques of pediatric heart transplantations.

CONCLUSION

Not only knowledge of the exact anatomy, but above all careful planning, interdisciplinary cooperation and surgical experience are prerequisites for surgical success.

Long-Term Outcomes and Characteristics Associated With Mortality of Adult Patients Post Fontan Surgery: 27-Year Single-Center Experience

Data on the characteristics and long-term outcomes of patients who underwent Fontan surgery and surviving into adulthood are limited. We aimed to describe our center's long-term experience with this unique patient population. Included were adult patients who had undergone Fontan surgery and were followed up at our Adult Congenital Heart Disease clinic between the years 1994 and 2021. We describe cardiac and noncardiac morbidities, medical treatment, laboratory data, echocardiographic characteristics, and all-cause mortality. The primary outcome was a composite of heart failure hospitalizations or death. A total of 107 patients who underwent Fontan surgery were followed up during the study period; 46.7% were male. The mean age at time of Fontan was 7.4 ± 6.2 years and the mean age at the last follow-up or at the time of an outcome event was 35.0 ± 8.0 years (range 21.1 to 62.8). At the last documented follow-up, 74.7% of the cohort were in New York Heart Association functional class I/II. The common morbidities included atrial arrythmias (37%) and stroke (17%). The primary outcome occurred in 17.7%. By the end of the study period, 9.3% of the patients in the cohort died. In a multivariate logistic regression analysis, controlling for gender, age, and Fontan type, worse functional class at the last follow-up (New York Heart Association III/IV vs I/II) was significantly associated with the risk of the primary outcome (odds ratio 34.57, 95% confidence interval 6.728 to 177.623, p <0.001). In conclusion, long-term outcomes of patients surviving into adulthood with a Fontan circulation is encouraging. Most of these patients achieve good functional cardiovascular status, despite the complex anatomy and a substantial burden of co-morbid conditions, specifically, atrial arrythmias and thrombotic events. Functional class was independently associated with heart failure hospitalizations and mortality.

Comparison of Functional Health Status and Health Related Quality of Life Between Adult Patients With Fontan Procedure and Noncongenital Heart Diseases

To compare functional health status and Health Related Quality of Life (HRQoL) between Fontan and non-congenital heart disease (CHD) patients in an Asian population. Functional health status and HRQoL (New York Heart Association (NYHA) functional class, Duke Activity Status Index (DASI), HeartQol and EQ-5D-5L) were measured. A total of 65 patients (twenty Fontan patients, mean age 28 ± 5; and 45 age-matched non-CHD patients, mean age 33 ± 5) were recruited. After adjustment for age, gender and ethnicity, there were no significant differences in functional health status and HRQoL between groups. In an Asian population, Fontan patients have similar functional health status and Health Related Quality of Life compared to non-CHD patients.

Peak Oxygen Consumption (V̇O 2peak ) Recovery Delay in a Pediatric Fontan Population

PURPOSE

The purpose of this study is to identify predictors and correlates of VO2RD in youth with Fontan.

METHODS

Cardiopulmonary exercise test data was used from a single center, cross-sectional study of children and adolescents (age, 8-21 yr) with Fontan physiology. The VO2RD was determined using time (s) to <90% of V̇O 2peak and categorized as "low" (≤10 s) or "high" (≥10 s). t Tests and χ 2 analysis were used to compare continuous and categorical variables, respectively.

RESULTS

The analysis sample included 30 adolescents with Fontan physiology (age, 14.2 ± 2.4 yr; 67% male) with either right ventricular (RV) dominant (40%) or co/left ventricular (Co/LV) dominant (60%) systemic ventricular morphology. There were no differences in V̇O 2peak between the high and low VO2RD groups (high = 1.3 ± 0.4 L·min -1 ; low = 1.3 ± 0.3 L·min -1 ; P = 0.97). VO2RD in participants with RV dominance was significantly greater than in patients with Co/LV dominance (RV = 23.8 ± 15.8 s; Co/LV = 11.8 ± 16.1 s; P = 0.03).

CONCLUSIONS

V̇O 2peak was not correlated with VO2RD when analyzed as high/low VO2RD groups. However, morphology of the systemic single ventricle (RV vs Co/LV) may be related to rate of recovery in V̇O 2 after a peak cardiopulmonary exercise test.

Severe Fontan-Associated Liver Disease and Its Association With Mortality

Background Data are rare about the incidence of severe Fontan-associated liver disease (FALD) and its association with mortality. We sought to: (1) estimate the probability of developing severe FALD in patients who undergo the Fontan procedure (Fontan patients), compared with severe liver complications in patients with a ventricular septal defect; (2) assess the severe FALD-mortality association; and (3) identify risk factors for developing severe FALD. Methods and Results Using the Quebec Congenital Heart Disease database, a total of 512 Fontan patients and 10 232 patients with a ventricular septal defect were identified. Kaplan-Meier curves demonstrated significantly higher cumulative risk of severe FALD in Fontan patients (11.95% and 52.24% at 10 and 35 years, respectively), than the risk of severe liver complications in patients with a ventricular septal defect (0.50% and 2.75%, respectively). At 5 years, the cumulative risk of death was 12.60% in patients with severe FALD versus 3.70% in Fontan patients without FALD (log-rank P=0.0171). Cox proportional hazard models identified significant associations between the development of severe FALD and congestive heart failure and supraventricular tachycardia, with hazard ratios (HRs) of 2.36 (95% CI, 1.38-4.02) and 2.45 (95% CI, 1.37-4.39), respectively. More recent Fontan completion was related to reduced risks of severe FALD, with an HR of 0.95 (95% CI, 0.93-0.97) for each more recent year. Conclusions This large-scale population-based study documents that severe FALD in Fontan patients was associated with a >3-fold increase in mortality. The risk of FALD is time-dependent and can reach >50% by 35 years after the Fontan operation. Conditions promoting poor Fontan hemodynamics were associated with severe FALD development.

2023 HRS expert consensus statement on the management of arrhythmias during pregnancy

This international multidisciplinary expert consensus statement is intended to provide comprehensive guidance that can be referenced at the point of care to cardiac electrophysiologists, cardiologists, and other health care professionals, on the management of cardiac arrhythmias in pregnant patients and in fetuses. This document covers general concepts related to arrhythmias, including both brady- and tachyarrhythmias, in both the patient and the fetus during pregnancy. Recommendations are provided for optimal approaches to diagnosis and evaluation of arrhythmias; selection of invasive and noninvasive options for treatment of arrhythmias; and disease- and patient-specific considerations when risk stratifying, diagnosing, and treating arrhythmias in pregnant patients and fetuses. Gaps in knowledge and new directions for future research are also identified.

Determinants of Advanced Liver Fibrosis in Adult Patients After Fontan Palliation: Usefulness of Ultrasound Transient Elastography

BACKGROUND

Fontan-associated liver disease is an increasing concern. Our aim was to assess prevalence and predictors of advanced liver fibrosis with a specific focus on utility of liver stiffness measurement by ultrasound transient elastography.

METHODS

A total of 97 adult Fontan patients (55% male, median age: 23.1 years, interquartile range [IQR]: 18.7-30.6); 92 (95%) were evaluated with transient elastography, and 50 (52%) underwent transjugular liver biopsy. Advanced liver fibrosis was defined as congestive hepatic fibrosis score 3 or 4.

RESULTS

Only 4 patients (4%) had liver stiffness values < 10 kilopascal (kPa). Liver-stiffness measurements correlated weakly with peak oxygen uptake on exercise testing and Fontan pressure but not with Model for End-Stage Liver Disease excluding INR (MELD-XI) score or spleen size. Serial follow-up liver stiffness measurements in 73 clinically stable patients showed large variability among individual patients. Advanced liver fibrosis was present in 35 of 50 (70%) patients on liver biopsy and was associated to MELD-XI-Score ≥ 11 and splenomegaly but not to liver-stiffness measurements. Advanced liver fibrosis was not associated with patient age or time since Fontan operation but with younger age at completion of Fontan (3.7 years, IQR: 2.3-6.3 vs 6.8 years; IQR: 3.5-12.1; P = 0.037).

CONCLUSIONS

In our cohort, advanced liver fibrosis was present in the majority of adult Fontan patients. Liver stiffness as measured by transient elastography was not associated with the degree of liver fibrosis. Because of its high variability on serial measurements, it seems not to be useful for clinical decision making. The unexpected finding that younger age at completion of Fontan was associated with advanced liver fibrosis merits further evaluation.

Cardiac magnetic resonance parameters associated with successful conversion from a single ventricular to a one-and-a-half or biventricular circulation in patients with a hypoplastic right ventricle

BACKGROUND

Some patients with pulmonary atresia with an intact ventricular septum (PA/IVS) or a left ventricle dominant atrioventricular canal defect (LDAVC) with a hypoplastic right ventricle (RV) and univentricular (1 V) circulation may be candidates for conversion to either a complete biventricular (2 V) repair or a one-and-a-half ventricle repair (1.5 V). We sought to identify pre-operative cardiovascular magnetic resonance (CMR) findings associated with successful conversion from 1V to 1.5V or 2V circulation.

METHODS

In this single center retrospective study, subjects with PA/IVS or LDAVC and no conotruncal abnormalities were included if they had a 1 V circulation at the time of CMR followed by a surgical intervention intended to convert them to a 1.5 V or 2 V circulation. Conversion failure was defined as any of the following: (1) oxygen saturation < 90% at the most recent follow-up, (2) conversion back to a 1.5 V or 1 V circulation, or (3) death.

RESULTS

In the PA/IVS cohort (n = 15, median age 1.32 years), 10 patients underwent surgical conversion to a 1.5 V circulation and 5 to a 2 V circulation. In the attempted 1.5 V group, there were 2 failures, and these cases had a lower RV mass (p = 0.04). In the attempted 2 V group, there was 1 failure, and no CMR parameters were significantly different compared to the successes. Among the successful 2 V group patients, the minimum RV end-diastolic volume (EDV) was 27 ml/m2. In the LDAVC cohort (n = 15, median age 1.0 years), 1 patient underwent surgical conversion to a 1.5 V circulation and 14 patients to a 2 V circulation. In the attempted 1.5 V group, the 1 conversion was a failure and had an RV EDV of 15 ml/m2. In the attempted 2 V group, there were 2 failures, and these cases had a smaller RV:LV stroke volume ratio (p = 0.05) and a lower RV ejection fraction (p = 0.05) compared to the successes. Among the successful 2 V group patients, the minimum RV EDV was 22 ml/m2.

CONCLUSIONS

We identified multiple CMR parameters associated with successful conversion from 1 V circulation to 1.5 V or 2 V circulation in patients with PA/IVS and LDAVC. This information may improve patient selection for conversion procedures and encourage larger studies to better define the role of CMR.

Atrial Arrhythmias in Adults with Fontan Palliation

Single ventricle physiology is a rare form of congenital heart disease and was, historically, a uniformly lethal condition. However, the atriopulmonary Fontan operation, and its successive iterations, the lateral tunnel and extracardiac conduit Fontan, became the fundamental approach to treating single ventricle heart disease. Over time, dysrhythmias are some of the most common complications with Fontan physiology, compounding morbidity and mortality. Atrial arrhythmias are prevalent in the Fontan population and occur in about 15-60% of patients with Fontan palliation, increasingly with age. Diagnosing atrial arrhythmias in patients with Fontan palliation may be challenging because of low voltage amplitudes arising from myopathic atrial tissue making it difficult to clearly assess atrial depolarization on surface electrocardiograms (ECG), vague symptoms not suggestive of tachyarrhythmia, or atrial arrhythmia with ventricular rates below 100 beats per minute. Intra-atrial reentrant tachycardia (IART) is the most common type of supraventricular tachycardia in adults with Fontan palliation. Acute management of atrial arrhythmias in patients with Fontan palliation involves prompt assessment of a patient's hemodynamic stability, anticoagulation and thrombosis risk, systemic ventricular function, and risk of sedation or anesthesia if needed. Long-term management of atrial arrhythmias is often multifactorial and may include long-term anti-arrhythmic therapy, permanent pacing, and ablation. The best approach for the management of atrial arrhythmias in adults with Fontan palliation is patient-specific and involves collaboration between congenital electrophysiologists, adult congenital cardiologists, and the patient.

Transient liver elastography in the follow-up of Fontan patients: results of a nation wide survey in Germany

Introduction

Fontan-palliated patients are at risk for the development of Fontan-associated liver disease (FALD). Currently, there is no consensus on how to stage FALD. Transient elastography (TE) is a rapid, non-invasive method to assess FALD and liver fibrosis.

Method

To assess the availability and conditions of using TE to monitor liver disease in Fontan patients in german centers for pediatric cardiology and to propose the introduction of a standardized national protocol for the monitoring of liver disease, we developed a questionnaire.

Results

In total, 95 valid questionnaires were collected. Only 20% of the centers offer the TE investigation directly. Most of the centers transfer the patients to another department or center (40%) or didńt offer TE (40%). In only 2.6% of the centers TE is performed directly by the cardiologist. Most of the centers transfer the patients to a other department. In 29.2% TE is performed only at a certain age of the patients and in 27.7% it is performed if the patients present symptoms of failing Fontan. In only 13.9% of the centers TE is proposed in all the Fontan patients on a routine basis. Most often TE is performed only from the beginning of the adolescence. In the majority of answers it was not known if the patients are fasting for the examination (68%) or not and if the TE examination had to be performed in a specific breathing phase during TE (Inspiration/Expiration, 90%). In the majority, TE is not offered routinely (46.9%).

Discussion

To date in Germany, TE is only used in a few numbers of centers specialized in Fontan follow-up. A standardized protocol to use TE is currently not existing. With regard to the feasibility of the examination, it is evident that TE is a quick, cheap and easy method to distinguish between cases with and without progressive FALD. This makes TE a useful and prognostic tool for screening of liver disease and to failing Fontan circulation.

Conclusion

We propose a systematic TE evaluation of possible liver congestion and fibrosis, as a part of the routine follow-up of Fontan patients.

Unique Pulmonary Hypertensive Vascular Diseases Associated with Heart and Lung Developmental Defects

Although pediatric pulmonary hypertension (PH) shares features and mechanisms with adult PH, there are also some significant differences between the two conditions. Segmental PH is a unique pediatric subtype of PH with unclear and/or multifactorial pathophysiological mechanisms, and is often associated with complex congenital heart disease (CHD), pulmonary atresia with ventricular septal defect, and aortopulmonary collateral arteries. Some cases of complex CHD, associated with a single ventricle after Fontan operation, show pathological changes in the small peripheral pulmonary arteries and pulmonary vascular resistance similar to those observed in pulmonary arterial hypertension (PAH). This condition is termed as the pediatric pulmonary hypertensive vascular disease (PPHVD). Recent advances in genetics have identified the genes responsible for PAH associated with developmental defects of the heart and lungs, such as TBX4 and SOX17. Targeted therapies for PAH have been developed; however, their effects on PH associated with developmental heart and lung defects remain to be established. Real-world data analyses on the anatomy, pathophysiology, genetics, and molecular biology of unique PPHVD cases associated with developmental defects of the heart and lungs, using nationwide and/or international registries, should be conducted in order to improve the treatments and prognosis of patients with these types of pediatric PH.

Percutaneous Cavopulmonary Assist: From Design to 96 Hour Survival in Lethal Cavopulmonary Failure Sheep

We are developing a clinically practical percutaneous double lumen cannula (DLC)-based cavopulmonary assist (CPA) system to support failing Fontan patients. In this study, our CPA DLC was redesigned for even blood flow, minimal recirculation, and easy insertion/deployment. After bench testing, this new CPA system was evaluated for 4 hours (n = 10) and 96 hours (n = 5) in our clinically relevant lethal cavopulmonary failure (CPF) sheep model for ease of cannulation/deployment, reversal of CPF hemodynamics/end-organ hypoperfusion, and durability/biocompatibility. Cavopulmonary failure was achieved in all sheep. All DLCs were successfully inserted/deployed into Fontan anatomy. Cavopulmonary assist reversed CPF with normalized central venous pressure and cardiac output. All survival sheep were ambulatory with normal eating/drinking. One sheep was euthanized after 6 hours from cannula kinking, and one sheep died of hypokalemia after 8 hours. Three sheep survived 96 hours with normal hemodynamics. Free hemoglobin was only 3.7 ± 1.2 mg/dl at 96 hours, indicating negligible hemolysis. Creatinine, blood urea nitrogen, and lactate increased from hypoperfusion but normalized by 72 hours CPA. Necropsy showed only a small, immobilized thrombus ring at umbrella attachment to DLC. Our DLC-based system provided total ambulatory CPA in a lethal CPF sheep model with 96 hour survival and complete reversal of hemodynamics and end-organ hypoperfusion.

Austin Powers' Steamroller: Lessons Learned to Benefit Patients with Congenital Heart Disease

A structural crisis is brewing in advanced care for patients with congenital heart disease (CHD)-specifically, single-ventricle patients palliated by the Fontan procedure. The largest study evaluating management practices in pediatric cardiac teams found that 93% of providers believe that after the Fontan procedure, patients "will eventually have signs/symptoms of heart failure (HF) and will need a heart transplant (HT) at some point in their lives."1 Despite this, the majority either disagreed about (45%) or were undecided about (24%) "whether routine evaluation by a HF/HT cardiologist is needed." This may be, in part, attributable to the lack of an HF/HT subspecialty in the American College of Pediatrics, but these findings highlight a concerning disconnect in the minds of providers caring for patients undergoing the Fontan procedure, for whom the providers' preparation seems incongruous in terms of the anticipated endpoint. This disconnect would likely be even worse had the survey been conducted in adult providers, given that the providers of care for adults with congenital heart disease (ACHD) have limited required HF/HT training, and adult HF/HT cardiologists have little required training in CHD.

Subcutaneous defibrillator use with unipolar pacemakers: Cautiously possible

Implantation of subcutaneous implantable cardioverter-defibrillator in a patient with existing unipolar pacemaker is against manufacturer recommendations. We report the case of a successful subcutaneous implantable cardioverter-defibrillator implantation in a patient with Fontan circulation and concomitant active unipolar pacing and present a summary of recommendations when considering subcutaneous implantable cardioverter-defibrillator implantation with unipolar pacing. Recommendations included: pre-procedure screening, rescreening during implantation and ventricular fibrillation induction, pacemaker programming, and post-procedure investigations.

Echocardiographic Strain to Predict Need for Transplant or Mortality in Fontan Patients with Hypoplastic Left Heart Syndrome

Despite recent advances, hypoplastic left heart syndrome (HLHS) patients subsequent to the Fontan still have significant morbidity and mortality. Some require heart transplant due to systemic ventricular dysfunction. Limited data exist on timing for transplant referral. This study aims to correlate systemic ventricular strain by echocardiography to transplant-free survival. HLHS patients who had Fontan palliation at our institution were included. Patients were divided into: 1) Required transplant or experienced mortality (composite end point); 2) Did not require transplant or survived. For those who experienced the composite endpoint, the last echocardiogram prior to the composite outcome was used, while for those who did not experience the composite endpoint the last echocardiogram obtained was used. Several qualitative and quantitative parameters were analyzed with focus on strain parameters. Ninety-five patients with HLHS Fontan palliation were identified. Sixty-six had adequate images and eight (12%) experienced transplant or mortality. These patients had greater myocardial performance index by flow Doppler (0.72 versus 0.53, p = 0.01), higher systolic/diastolic duration ratio (1.51 versus 1.13, p = 0.02), lower fractional area change (17.65 versus 33.99, p < 0.01), lower global longitudinal strain (GLS) (-8.63 versus - 17.99, p < 0.01), lower global longitudinal strain rate (GLSR) (- 0.51 versus - 0.93, p < 0.01), lower global circumferential strain (GCS) (-6.68 versus -18.25, p < 0.01), and lower (GCSR) global circumferential strain rate (-0.45 versus -1.01, p < 0.01). ROC analysis demonstrated predictive value for GLS - 7.6 (71% sensitive, 97% specific, AUC 81%), GLSR -0.58 (71% sensitive, 88% specific, AUC 82%), GCS - 10.0 (86% sensitive, 91% specific, AUC 82%), and GCSR -0.85 (100% sensitive, 71% specific, AUC 90%). GLS and GCS can help predict transplant-free survival in patients with hypoplastic left heart syndrome having undergone Fontan palliation. Higher strain values (closer to zero) may be a helpful tool in determining when transplant evaluation is warranted in these patients.

Thromboembolic Complications in Adult Patients Following Fontan Procedure-A Multicenter Study

BACKGROUND

Morbidity and mortality following Fontan (FO) surgery are primarily thromboembolic in nature. However, follow-up data regarding thromboembolic complications (TECs) in adult patients after FO procedure are inconsistent. In this multicenter study, we investigated the incidence of TECs in FO patients.

METHODS

We studied 91 patients who underwent FO procedure. Clinical data, laboratory, and imaging investigations were collected prospectively during the scheduled medical appointments in 3 Adult Congenital Heart Disease Departments in Poland. TECs were recorded during a median follow-up of 31 months.

RESULTS

Four patients (4.4%) were lost to follow-up. The mean age of patients was 25.3 (±6.0) years at enrollment, and the mean time between FO operation and investigation was 22.1 (±5.1) years. A total of 21 out of 91 patients (23.1%) had a history of 24 TECs since an FO procedure, mainly pulmonary embolism (PE; n = 12, 13.2%), including 4 (33.3%) silent PE. The mean time since FO operation to the first TEC was 17.8 (±5.1) years. During follow-up, we documented 9 TECs in 7 (8.0%) patients, mainly PE (n = 5, 5.5%). Most patients with TEC had a left type of systemic ventricle (57.1%). Three patients (42.9%) were treated with aspirin, 3 (3.4%) with Vitamin K antagonists or novel oral anticoagulants, and 1 patient had no antithrombotic treatment at the time of TEC occurrence. Supraventricular tachyarrhythmias were present in 3 patients (42.9%).

CONCLUSIONS

This prospective study shows that TECs are common in FO patients, and a significant number of these events occur during adolescence and young adulthood. We also indicated how much TECs are underestimated in the growing adult FO population. The complexity of the problem requires more studies, especially to standardize the prevention of TECs in the whole FO population.

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.

Exercise Capacity, NT-proBNP, and Exercise Hemodynamics in Adults Post-Fontan

BACKGROUND

Cardiopulmonary exercise testing (CPET) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurement are frequently performed in adults post-Fontan, but their correlations with exercise invasive hemodynamics are poorly understood. Moreover, whether exercise cardiac catheterization provides incremental prognostic information is unknown.

OBJECTIVES

The authors sought to correlate resting and exercise Fontan pressures (FP) and pulmonary artery wedge pressure (PAWP) with peak oxygen consumption (VO2) on CPET, NT-proBNP, and clinical outcomes.

METHODS

This was a retrospective cohort of 50 adults (age ≥18 years) post-Fontan undergoing supine exercise venous catheterization between 2018 and 2022.

RESULTS

Median age was 31.5 years (IQR: 23.7-36.5 years). Ventricular ejection fraction was 48.5% ± 13.0%. Exercise FP and PAWP were related to peak VO2 and ln NT-proBNP levels. Patients with peak VO2 <50% predicted had higher exercise FP (30.0 ± 6.8 mm Hg vs 19 mm Hg [IQR: 16-24 mm Hg]; P < 0.001) and PAWP (25.9 ± 6.3 mm Hg vs 15.1 ± 7.0 mm Hg; P <0.001) compared with those with more preserved exercise capacity. Exercise FP (30.0 ± 7.1 mm Hg vs 23.2 ± 7.2 mm Hg; P = 0.003) and PAWP (25.1 ± 6.7 mm Hg vs 18.8 ± 7.9 mm Hg; P = 0.006) were higher in those with NT-proBNP levels ≥300 pg/mL. During a follow-up of 0.9 years (IQR: 0.6-2.9 years), exercise FP and PAWP remained independently associated with a composite of death, cardiac transplantation, or hospitalization due to heart failure/refractory arrhythmias after adjusting for confounders.

CONCLUSIONS

In adults post-Fontan, resting and exercise FP and PAWP were inversely related to exercise capacity on noninvasive CPET, and exercise hemodynamics were directly related to NT-proBNP levels. Exercise FP and PAWP were independently associated with clinical outcomes and might be more sensitive than resting values to predict clinical outcomes.

Incremental prognostic value of myocardial strain over ventricular volume in patients with repaired tetralogy of Fallot

OBJECTIVES

The relative incremental predictive value of myocardial deformation over ventricular volume for future adverse events in patients with repaired tetralogy of Fallot (rTOF) remains unknown. We aimed to determine the incremental prognostic value of myocardial deformation over ventricular volume to predict adverse events in patients with rToF.

METHODS

We retrospectively included patients with rTOF who completed cardiac magnetic resonance (CMR) and follow-up in our hospital from January 2014 to October 2020, and stratified according to the presence or absence of adverse events during follow-up. The strain parameters of the right ventricular (RV) and left ventricular (LV) were obtained from CMR-derived feature tracking. Multivariable Cox proportional hazard models and net reclassification improvement analysis were used to analyze the prognostic information of biventricular strain and volume parameters in rTOF patients.

RESULTS

Among 98 patients with rTOF, 54 (55.1%) experienced primary and/or secondary events during a median follow-up period of 27.0 months. Univariable analysis indicated that RV volume and strain were significantly associated with both primary events and all adverse events (all p < .01). Multivariable Cox regression and net reclassification improvement analyses achieved incremental global χ² (all p < .001), C index (all p < .001), and overall correct reclassification by sequentially adding CMR-derived RV volume, RV strain and LV strain parameters to preexisting clinical factors in adverse events model analyses.

CONCLUSIONS

RV and LV myocardial deformation provided incremental prognostic information and significant improvement for risk stratification over RV size and clinical variables and therefore can be combined to further enhance prognostication.

KEY POINTS

• RV volume and strain were significantly associated with both primary events and all adverse events, whereas LV volume and strain were associated with primary events. • Ventricular myocardial deformation is a strong predictor of adverse outcomes of patients with repaired tetralogy of Fallot, providing increased prognostic information and significantly improved risk stratification over ventricular size.

Evaluation of right ventricular myocardial deformation properties in fetal hypoplastic left heart by two-dimensional speckle tracking echocardiography

PURPOSE

Right ventricular (RV) function influences the outcome of hypoplastic left heart (HLH) patients. This study aimed to confirm the assumption of prenatal RV remodeling and possible influencing factors of myocardial restructuring using two-dimensional speckle tracking echocardiography (2D STE).

METHODS

This is a retrospective cross-sectional cohort study including HLH fetuses and gestational age-matched controls. Based on a four-chamber view, cine loops were stored with 60 frames per second. Global longitudinal peak systolic strain (GLPSS) of the RV was retrospectively determined and compared to healthy controls. Furthermore, HLH subgroups were built according to the presence of left ventricular endocardial fibroelastosis (LV-EFE) and restrictive foramen ovale (FO) to investigate the effect of these compromising factors on myocardial deformation.

RESULTS

A total of 41 HLH fetuses and 101 controls were included. Gestational age at fetal assessment was similarly distributed in both groups (controls: 26.0 ± 5.6 weeks vs. HLH: 29.1 ± 5.6 weeks). Relating to RV-GLPSS values, fetuses with HLH demonstrated lower mean values than healthy control fetuses (- 15.65% vs. - 16.80%, p = 0.065). Cases with LV-EFE (n = 11) showed significantly lower mean values compared to such without LV-EFE (n = 30) (RV-GLPSS: - 12.12% vs. - 16.52%, p = 0.003). No significant differences were observed for cases with FO restriction (n = 10).

CONCLUSIONS

In HLH the RV undergoes prenatal remodeling, leading to an adaptation of myocardial function to LV conditions. Further explorations by STE should expand knowledge about RV contraction properties in HLH and its impact on surgical outcome.

Cardiac Transcriptome Remodeling and Impaired Bioenergetics in Single-Ventricle Congenital Heart Disease

The mechanisms responsible for heart failure in single-ventricle congenital heart disease are unknown. Using explanted heart tissue, we showed that failing single-ventricle hearts have dysregulated metabolic pathways, impaired mitochondrial function, decreased activity of carnitine palmitoyltransferase activity, and altered functioning of the tricarboxylic acid cycle. Interestingly, nonfailing single-ventricle hearts demonstrated an intermediate metabolic phenotype suggesting that they are vulnerable to development of heart failure in the future. Mitochondrial targeted therapies and treatments aimed at normalizing energy generation could represent a novel approach to the treatment or prevention of heart failure in this vulnerable group of patients.

A Case of Resection of Hepatocellular Carcinoma in a Patient With Fontan-Associated Liver Disease

The Fontan procedure (FP) is an operation used in patients with congenital single ventricle disease. The long-term prognosis after surgery has improved due to technological advances. However, the hemodynamics after FP are complicated. There are some reports of Fontan-associated liver disease (FALD) after FP. We report a case of a young woman who developed hepatocellular carcinoma due to FALD.

Fontan-associated liver disease: Diagnosis, surveillance, and management

The Fontan operation is a lifesaving procedure for patients with functional single-ventricle congenital heart disease, where hypoplastic left heart syndrome is the most frequent anomaly. Hemodynamic changes following Fontan circulation creation are now increasingly recognized to cause multiorgan affection, where the development of a chronic liver disease, Fontan-associated liver disease (FALD), is one of the most important morbidities. Virtually, all patients with a Fontan circulation develop liver congestion, resulting in fibrosis and cirrhosis, and most patients experience childhood onset. FALD is a distinctive type of congestive hepatopathy, and its pathogenesis is thought to be a multifactorial process driven by increased nonpulsatile central venous pressure and decreased cardiac output, both of which are inherent in the Fontan circulation. In the advanced stage of liver injury, complications of portal hypertension often occur, and there is a risk of developing secondary liver cancer, reported at young age. However, FALD develops with few clinical symptoms, a surprisingly variable degree of severity in liver disease, and with little relation to poor cardiac function. The disease mechanisms and modifying factors of its development are still not fully understood. As one of the more important noncardiac complications of the Fontan circulation, FALD needs to be diagnosed in a timely manner with a structured monitoring scheme of disease development, early detection of malignancy, and determination of the optimal time point for transplantation. There is also a clear need for consensus on the best surveillance strategy for FALD. In this regard, imaging plays an important role together with clinical scoring systems, biochemical workups, and histology. Patients operated on with a Fontan circulation are generally followed up in cardiology units. Ultimately, the resulting multiorgan affection requires a multidisciplinary team of healthcare personnel to address the different organ complications. This article discusses the current concepts, diagnosis, and management of FALD, with special emphasis on the role of different imaging techniques in the diagnosis and monitoring of disease progression, as well as current recommendations for liver disease surveillance.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Opportunities and short-comings of the axolotl salamander heart as a model system of human single ventricle and excessive trabeculation

Few experimental model systems are available for the rare congenital heart diseases of double inlet left ventricle (DILV), a subgroup of univentricular hearts, and excessive trabeculation (ET), or noncompaction. Here, we explore the heart of the axolotl salamander (Ambystoma mexicanum, Shaw 1789) as model system of these diseases. Using micro-echocardiography, we assessed the form and function of the heart of the axolotl, an amphibian, and compared this to human DILV (n = 3). The main finding was that both in the axolotl and DILV, blood flows of disparate oxygen saturation can stay separated in a single ventricle. In the axolotl there is a solitary ventricular inlet and outlet, whereas in DILV there are two separate inlets and outlets. Axolotls had a lower resting heart rate compared to DILV (22 vs. 72 beats per minute), lower ejection fraction (47 vs. 58%), and their oxygen consumption at rest was higher than peak oxygen consumption in DILV (30 vs. 17 ml min^-1 kg^-1). Concerning the ventricular myocardial organization, histology showed trabeculations in ET (n = 5) are much closer to the normal human setting than to the axolotl setting. We conclude that the axolotl heart resembles some aspects of DILV and ET albeit substantial species differences exist.

Longitudinal changes in ventricular size and function are associated with death and transplantation late after the Fontan operation

BACKGROUND

Cross-sectional studies have reported that ventricular dilation and dysfunction are associated with adverse clinical outcome in Fontan patients; however, longitudinal changes and their relationship with outcome are not known.

METHODS

This was a single-center retrospective analysis of Fontan patients with at least 2 cardiovascular magnetic resonance (CMR) scans without intervening interventions. Serial measures of end-diastolic volume index (EDVI), end-systolic volume index (ESVI), ejection fraction (EF), indexed mass (massi), mass-to-volume ratio, and end-systolic wall stress (ESWS) were used to estimate within-patient change over time. Changes were compared for those with and without a composite outcome (death, heart transplant, or transplant listing) as well as between patients with left (LV) and right ventricular (RV) dominance.

RESULTS

Data from 156 patients were analyzed with a mean age at 1st CMR of 17.8 ± 9.6 years. 490 CMRs were included with median of 3 CMRs/patient (range 2-9). On regression analysis with mixed effects models, volumes and ESWS increased, while mass, mass-to-volume ratio, and EF decreased over time. With a median follow-up of 10.2 years, 14% met the composite outcome. Those with the composite outcome had a greater increase in EDVI compared to those without (4.7 vs. 0.8 ml/BSA1.3/year). Compared with LV dominance, RV dominance was associated with a greater increase in ESVI (1.4 vs. 0.5 ml/BSA1.3/year), a greater decrease in EF (- 0.61%/year vs. - 0.24%/year), and a higher rate of the composite outcome (21% vs. 8%).

CONCLUSIONS

Ventricles in the Fontan circulation exhibit a steady decline in performance with an increase in EDVI, ESVI, and ESWS, and decrease in EF, mass index, and mass-to-volume ratio. Those with death or need for heart transplantation have a faster increase in EDVI. Patients with rapid increase in EDVI (> 5 ml/BSA1.3/year) may be at a higher risk of adverse outcomes and may benefit from closer surveillance. RV dominance is associated with worse clinical outcomes and remodeling compared to LV dominance.

Prevalence and Treatment Outcomes of Arrhythmias in Patients with Single Ventricle Physiology over the Age of 40 Years

Background: Arrhythmias are a well known complication in patients with single ventricle physiology (SVP). However, there is still a lack of data regarding arrhythmias in older patients. The aim of this study was to analyze arrhythmia type and frequency, treatment and recurrence rates in patients with SVP over the age of 40 years. Methods: Data was obtained retrospectively from clinical records. All patients > 40 years with SVP with arrhythmias between 2005 and 2018 were included in the study. Treatment was classified as medical, interventional (electrophysiological studies (EPS) in combination with catheter ablation) or direct current cardioversion (DCCV). Results: Altogether, 29 patients (11 female; mean 47.5 ± 4.6 years) with 85 arrhythmia episodes were identified. The median follow-up time was 6.3 years. Cavo-tricuspid (CTI) and non-CTI related intra-atrial reentrant tachycardia (IART) and atrial fibrillation (AF) were most common (48.2% and 37.6%, respectively). In total, 18 EPS/ablations were performed in 9 patients and 52 DCCVs in 20 patients. Acute success was 98% for DCCV and 72.2% for EPS/ablation. Recurrence rate was high (70% for DCCV and 55% for EPS). AT recurrences occurred after a median of 8 and 2.5 months, respectively. On multivariate analyses, age was the only risk factor for arrhythmia recurrence (HR 0.58, 95% C.I. 0.43−0.78, p < 0.0001). Pacemaker implantation was necessary in seven patients (AV block n = 4, sinus node dysfunction n = 3) and one patient received an ICD for secondary prophylaxis. Sudden death occurred in three patients. Conclusions: The most common arrhythmias in patients with SVP > 40 years are IART and AF. Arrhythmia recurrence following EPS or DCCV is frequent. Older age is an independent risk factor for arrhythmia recurrence.

Impact of Udenafil on Echocardiographic Indices of Single Ventricle Size and Function in FUEL Study Participants

BACKGROUND

The FUEL trial (Fontan Udenafil Exercise Longitudinal) demonstrated statistical improvements in exercise capacity following 6 months of treatment with udenafil (87.5 mg po BID). The effect of udenafil on echocardiographic measures of single ventricle function in this cohort has not been studied.

METHODS

The 400 enrolled participants were randomized 1:1 to udenafil or placebo. Protocol echocardiograms were obtained at baseline and 26 weeks after initiation of udenafil/placebo. Linear regression compared change from baseline indices of single ventricle systolic, diastolic and global function, atrioventricular valve regurgitation, and mean Fontan fenestration gradient in the udenafil cohort versus placebo, controlling for ventricular morphology (left ventricle versus right ventricle/other) and baseline value.

RESULTS

The udenafil participants (n=191) had significantly improved between baseline and 26 weeks visits compared to placebo participants (n=195) in myocardial performance index (P=0.03, adjusted mean difference [SE] of changes between groups -0.03[0.01]), atrioventricular valve inflow peak E (P=0.009, 3.95 [1.50]), and A velocities (P=0.034, 3.46 [1.62]), and annular Doppler tissue imaging-derived peak e' velocity (P=0.008, 0.60[0.23]). There were no significant differences in change in single ventricle size, systolic function, atrioventricular valve regurgitation severity, or mean fenestration gradient. Participants with a dominant left ventricle had significantly more favorable baseline values of indices of single ventricle size and function (lower volumes and areas, E/e' ratio, systolic:diastolic time and atrioventricular valve regurgitation, and higher annular s' and e' velocity).

CONCLUSIONS

FUEL participants who received udenafil demonstrated a statistically significant improvement in some global and diastolic echo indices. Although small, the changes in diastolic function suggest improvement in pulmonary venous return and/or augmented ventricular compliance, which may help explain improved exercise performance in that cohort.

REGISTRATION

URL: https://clinicaltrials.gov; Unique Identifier: NCT02741115.

Efficacy of a phosphodiesterase type 5 inhibitor on the pulmonary artery index and postoperative hemodynamics after a Fontan operation

There have been no reports regarding the influence of a change in the pulmonary artery index before or after a Fontan operation. Moreover, the factors that might affect the change in the pulmonary artery index are unclear. This was a retrospective study, which included 94 patients who underwent a Fontan operation. We divided the patients into two groups according to the change in the pulmonary artery index before and after the Fontan operation: the increased pulmonary artery index group (n = 51) and decreased pulmonary artery index group (n = 43). The pulmonary artery index after the Fontan operation was significantly higher in the increased pulmonary artery index group than decreased pulmonary artery index group (p < 0.0001). The central venous pressure (p < 0.0001) and pulmonary vascular resistance (p = 0.007) were significantly lower in the increased pulmonary artery index group. The mixed venous oxygen saturation was significantly higher in the increased pulmonary artery index group (p < 0.0001). The pulmonary artery index was more increased in the patients who were administered a phosphodiesterase type 5 inhibitor than in those who were not (p = 0.03). The change in the pulmonary artery index reflected the hemodynamics after a Fontan operation during the short term. In that respect, phosphodiesterase type 5 inhibitors might be involved in the process.

Fontan failure: phenotypes, evaluation, management, and future directions

OBJECTIVES

Management of "failing" and "failed" Fontan circulation, particularly the indications, timing, and type of re-intervention, currently remains nebulous. Factors contributing to pathogenesis and mortality following Fontan procedure differ between children and adults.

METHODS

Since organ systems in individual patients are affected differently, we searched the extant literature for a "failing" and "failed" Fontan reviewing the clinical phenotypes, diagnostic modalities, pharmacological, non-pharmacological, and surgical techniques employed, and their outcomes.

RESULTS

A total of 410 investigations were synthesised. Although proper candidate selection, thoughtful technical modifications, timely deployment of mechanical support devices, tissue-engineered conduits, and Fontan takedown have decreased the peri-operative mortality from 9 to 15% and 1 to 3% per cent in recent series, pernicious changes in organ function are causing long-term patient attrition. In the setting of a failed Fontan circulation, literature documents three surgical options: Fontan revision, Fontan conversion, or cardiac transplantation. The reported morbidity of 25% and mortality of 8-10% among Fontan conversion continue to improve in select institutions. While operative mortality following cardiac transplantation for Fontan failure is 30% higher than for other CHDs, there is no difference in long-term survival with actuarial 10-year survival of around 54%. Mechanical circulatory assistance, stem cells, and tissue-engineered Fontan conduit for destination therapy or as a bridge to transplantation are in infancy for failing Fontan circulation.

CONCLUSIONS

An individualised management strategy according to clinical phenotypes may delay the organ damage in patients with a failing Fontan circulation. At present, cardiac transplantation remains the last stage of palliation with gradually improving outcomes.