State of the art of the Fontan strategy for treatment of univentricular heart disease

Leg-focused high-weight resistance training improves ventricular stroke volume, exercise capacity and strength in young patients with a Fontan circulation

AIMS

Effective therapy to improve exercise capacity in Fontan patients is lacking. Leg-focused high-weight resistance training might augment the peripheral muscle pump and thereby improve exercise capacity.

METHODS AND RESULTS

This randomized semi-cross-over controlled trial investigated the effects of a 12-week leg-focused high-weight resistance training plus high-protein diet, on (sub)maximal exercise capacity, cardiac function (assessed with cardiovascular magnetic resonance), muscle strength, and quality of life in paediatric Fontan patients. Twenty-eight paediatric Fontan patients were included, 27 patients, (median age 12.9 [10.5-15.7]), and successfully completed the programme. Peak oxygen uptake (PeakVO2) at baseline was reduced [33.3 mL/kg/min (27.1-37.4), 73% (62-79) of predicted]. After training PeakVO2/kg and Peak workload improved significantly with +6.2 mL/kg/min (95%CI: 3.4-9.0) (+18%) P < 0.001 and +22 Watts (95%CI: 12-32) (+18%) P < 0.001, respectively, compared to the control period. Indexed single ventricle stroke volume increased significantly [43 mL/beat/m2 (40-49) vs. 46 (41-53), P = 0.014], as did inferior vena cava flow [21 mL/beat/m2 (18-24) vs. 23 (20-28), P = 0.015], while superior vena cava flow remained unchanged. The strength of all measured leg-muscles increased significantly compared to the control period. Self-reported quality of life improved on the physical functioning and change in health domains of the child health questionnaire, parent-reported quality of life improved the bodily pain, general health perception, and change in health domains compared to the control period.

CONCLUSION

In a relatively large group of 27 older Fontan children, 12-weeks of leg-focused high-weight resistance training improved exercise capacity, stroke volume, (sub)maximal exercise capacity, muscle strength, and domains of quality of life.

REGISTRATION

International Clinical Trials: Trial NL8181.

Impact of early postoperative haemodynamic and laboratory parameters on outcome after the Fontan procedure

OBJECTIVE

To identify early postoperative haemodynamic and laboratory parameters predicting outcomes following total cavopulmonary connection.

METHODS

Patients who underwent total cavopulmonary connection between 2012 and 2021 were evaluated. Serial values of mean pulmonary artery pressure, mean arterial pressure, peripheral oxygen saturation, and lactate levels were collected. The influence of these variables on morbidities was analyzed. Cut-off values were calculated using the receiver operating characteristic analysis.

RESULTS

A total of 249 patients were included. All patients had previous bidirectional cavopulmonary shunt. Median age and weight at total cavopulmonary connection were 2.2 (1.8-2.7) years and 11.7 (10.7-13.4) kg, respectively. All patients were extubated in the ICU at a median of 3 (2-5) hours after ICU admission. Postoperative pulmonary artery pressure, around 12 hours after extubation, was significantly associated with chest tube drainage (p = 0.048), chylothorax (p = 0.021), ascites (p = 0.016), and adverse events (p = 0.028). Receiver operating characteristic analysis revealed a cut-off value of 13-15 mmHg for chest tube drainage and chylothorax and 17 mmHg for ascites and adverse events. Mean arterial pressure 1 hour after extubation was associated with prolonged chest tube drainage (p = 0.015) and adverse events (p = 0.008). Peripheral oxygen saturation 6 hours after extubation (p = 0.003) was associated with chest tube duration and peripheral oxygen saturation 1 hour after extubation (p < 0.001) was associated with ascites. Lactate levels on 2nd postoperative day (p = 0.022) were associated with ascites and lactate levels on 1st postoperative day (p = 0.009) were associated with adverse events.

CONCLUSIONS

Higher pulmonary artery pressure, lower mean arterial pressure, lower peripheral oxygen saturation, and higher lactate in early postoperative period, around 12 hours after extubation, predicted in-hospital and post-discharge adverse events following total cavopulmonary connection.

A 12-week lifestyle intervention: effects on fatigue, fear, and nutritional status in children with a Fontan circulation

Introduction

Children and adolescents with a Fontan circulation are less physically active compared to healthy peers. In the current study, effects of a 12-week lifestyle intervention on fatigue, fears regarding exercise, caloric intake, rest energy expenditure (REE), and body composition were measured in children with a Fontan circulation.

Methods

This study was a semi-cross-over randomized controlled trial. The lifestyle intervention consisted of a 12-week high-weight resistance training (three supervised training sessions a week) supported by high-protein diet (>2 g/kg) and tailored recommended caloric intake. Fatigue (measured by the validated PedsQol Multidimensional Fatigue Scale), fears regarding exercise (measured on a fear thermometer), REE (measured using indirect calorimetry), caloric intake and body composition using air displacement plethysmography, and four-skinfold method were measured before and after the intervention and control period.

Results

Twenty-seven pediatric Fontan patients, median age 12.9 years (IQR: 10.5-16.2), of the included 28 patients successfully completed the program. Before training, both child- and parent-reported levels of fatigue were significantly worse on all domains (general, sleep/rest, and cognitive fatigue) compared to healthy peers. After training, parent-reported fatigue significantly improved on the general and cognitive fatigue domains [effect size +16 points (7-25), p < 0.001, and +10 points (2-17), p = 0.015, compared to the control period]. Before training, fear regarding exercise scored on the fear thermometer was low for both children and parents (median score 1 and 2, respectively, on a scale of 0-8). After training, child-reported fear decreased further compared to the control period [effect size -1.4 points (-2.3 to -0.6), p = 0.001]. At baseline, children had increased REE +12% compared to reference values, which did not change after exercise. Children ate an average of 637 calories below recommended intake based on REE, caloric deficit became smaller after the intervention, and protein intake increased compared to the control period [-388 calories (-674 to -102), p = 0.008, and +15 g (0.4-30), p = 0.044]. Body fat percentage did not change significantly.

Conclusion

A 12-week lifestyle intervention improved parent-reported fatigue symptoms in the children, further decreased child-reported fears, and increased caloric and protein intake.

Cardiac Function and Serum Biomarkers throughout Staged Fontan Palliation: A Prospective Observational Study

Fontan patients undergo multiple cardiothoracic surgeries in childhood. Following these procedures, ventricular function is temporarily decreased, and recovers over months. This is presumably related to cardiopulmonary bypass, but this is incompletely understood. Throughout the Fontan palliation, cardiac function is also affected by volume unloading. We aimed to gain insight into the biological processes related to impaired ventricular function and recovery following Fontan palliations using a panel of biomarkers. Furthermore, we described changes in ventricular function across the Fontan palliation due to volume unloading. We performed a prospective multicenter observational study in patients undergoing partial (PCPC) or total cavo-pulmonary connection (TCPC). Patients underwent assessment-including echocardiography and blood sampling-before surgery (T1), at first follow-up (T2), and 1 year after their procedures (T3). Blood samples were analyzed using a biomarker panel (OLINK CVD-III). Ninety-two biomarkers were expressed as principal components (PC) to limit multiple statistical testing. We included 32 PCPC patients aged 7.2 [5.3-10.3] months, and 28 TCPC patients aged 2.7 [2.2-3.8] years. The single ventricular longitudinal strain (SV GLS) temporarily decreased for PCPC patients at T2 (-15.1 ± 5.6 (T1) to -13.5 ± 5.2 (T2) to -17.3 ± 4.5 (T3), p < 0.047 for all differences), but not following TCPC. The serum biomarkers were expressed as 4 PCs. PC1, including biomarkers of cell-cell adhesion, was not related to any patient characteristic. PC2, including biomarkers of superoxide anion regulation, increased at T2. PC3, including biomarkers of cardiovascular development, related to the stage of Fontan palliation. PC4 was of uncertain biological or clinical significance. No PC was found that related to ventricular performance. The SV GLS was temporarily diminished following PCPC, but not following TCPC. Several biomarkers were related to post-operative stress and adaptation to the PCPC or TCPC circulation, but none were related to the outcome.

Optimal Heart Rate May Improve Systolic and Diastolic Function in Patients with Fontan Circulation

(1) Background: The optimal heart rate, at which the E-wave and A-wave stand adjacent without any overlaps in the Doppler transmitral flow echocardiography, is associated with maximum cardiac output and favorable clinical outcomes in adult patients with systolic heart failure. However, the clinical implication of the echocardiographic overlap length in patients with Fontan circulation remains unknown. We investigated the relationship between heart rate (HR) and hemodynamics in Fontan surgery patients with and without beta-blockers. (2) Methods and Results: A total of 26 patients (median age 1.8 years, 13 males) were enrolled. At baseline, the plasma N-terminal pro-B-type natriuretic peptide was 2439 ± 3483 pg/mL, the fraction area change was 33.5 ± 11.4%, the cardiac index was 3.55 ± 0.90 L/min/m², and the overlap length was 45.2 ± 59.0 msec. Overlap length was importantly decreased after the one-year follow-up (7.60 ± 78.57 msec, p = 0.0069). Positive correlations were noted between the overlap length and A-wave and E/A ratio (p = 0.0021 and p = 0.0046, respectively). Ventricular end-diastolic pressure was significantly correlated with the overlap length in non-beta-blocker patients (p = 0.0483). (3) Conclusion: Overlap length may reflect the status of ventricular dysfunction. Hemodynamic preservation at lower HR could be critical for cardiac reverse remodeling.

Assessment of exercise capacity using field walking tests in patients after the Fontan procedure: A case-control study

BACKGROUND

Despite the frequent use of the 6-minute walk test (6MWT), exercise capacity has not been assessed with the incremental shuttle walk test (ISWT) in patients who have undergone the Fontan procedure. It is unclear whether these tests cause clinically relevant cardiorespiratory responses in these patients.

OBJECTIVES

We aimed to assess cardiorespiratory responses to the 6MWT and ISWT in Fontan patients, compare the responses with those in the controls, and examine the agreement between the two field tests.

METHODS

Submaximal exercise capacity was assessed using the 6MWT, maximal exercise capacity using the ISWT, quadriceps isometric muscle strength with a hand dynamometer, and body composition using a bioelectrical impedance device.

RESULTS

Twenty-one Fontan patients (16.42±6.63 years, 5F/16M) and 21 controls (16.57±4.30 years, 7F/14M) were included. While body composition was similar between the groups (p>0.05), quadriceps isometric muscle strength and 6MWT and ISWT distance were lower in the Fontan patients than in the controls (p<0.05). In both the 6MWT and ISWT, pre- and post-test heart rate (HR), oxygen saturation (SpO₂), dyspnea, and leg fatigue differed significantly between the Fontan patients and the controls (p<0.05). In addition, the ISWT resulted in a more significant change in HR, SpO₂, and leg fatigue than the 6MWT in the Fontan patients (p<0.05). Bland-Altman plots for the 6MWT vs. the ISWT indicated agreement between the two tests.

CONCLUSION

There were remarkable changes in HR, SpO₂, dyspnea, and leg fatigue in both tests. With similar safety to the 6MWT but with more caution applied for adverse events, the ISWT can also be performed as a field test to evaluate exercise capacity and identify more pronounced exercise-induced responses (especially oxygen desaturation) in Fontan patients.

Exercise capacity in a cohort of children with congenital heart disease

In patients with congenital heart disease (CHD), reduced exercise capacity can be a predictor for late complications and may be used to guide interventions. Yet, the interpretation of exercise capacity is challenged by changes in body composition during growth. Our aim was to create an overview of disease-specific exercise capacity in children with CHD. We performed a multicentre retrospective study of exercise capacity of CHD patients, aged 6-18 years, tested between January 2001 and October 2018. Sex-specific distribution graphs were made using the LMS method and height to relate to body size. We included all CHD with N > 50, including severe defects (e.g., univentricular heart, tetralogy of Fallot) and "simple" lesions as ventricular septum defect and atrial septum defect. We included 1383 tests of 1208 individual patients for analysis. The peak oxygen uptake (VO₂peak, 37.3 ml/min/kg (25th-75th percentile 31.3-43.8)) varied between specific defects; patients with univentricular hearts had lower VO_2peak compared with other CHD. All groups had lower VO_2peak compared to healthy Dutch children. Males had higher VO_2peak, W_peak and O₂pulse_peak than females. Sex- and disease-specific distribution graphs for VO_2peak, W_peak and O2pulse_peak showed increase in variation with increase in height.   Conclusion: Disease-specific distribution graphs for exercise capacity in children with CHD from a large multicentre cohort demonstrated varying degrees of reduced VO_2peak and W_peak. The distribution graphs can be used in the structured follow-up of patients with CHD to predict outcome and identify patients at risk. What is Known: • Children with congenital heart disease (COnHD) are at risk to develop heart failure, arrhytmia's and other complications. Exercise capacity may be an important predictor for outcome in children with ConHD. In children, the interpretation of exercise capacity poses an additional challenge related to physical changes during growth. What is New: • In this report of a multi-center cohort >1300 childrewn with ConHD, we related the changes in exercise capacity to length. We demonstrated that exercise capacity was reduced as compared with healthy children and we observed variation between disease groups. Patients with a univentricular circulation (Fontan) had worse exercise capacity. We constructed disease specific charts of development of exercise capacity throughout childhood, accessible via a web-site. These graphs may help practitioner to guide children with ConHD.

Failing Fontan cardiovascular support: Review

BACKGROUND

Although all congenital heart defects (CHD) present unique challenges, univentricular CHD are especially challenging given the difficulty of passively perfusing pulmonary blood flow. Three surgical procedures are required within the first years of life, with the final completing a Fontan circulation in which the inferior vena cava is connected to the pulmonary artery and previously connected superior vena cava. This allows passive venous return to the pulmonary circulation then flow into the single ventricle for systemic circulation.

METHODS

Although a Fontan provides successful palliation for two to three decades, many complications can arise as pulmonary resistance must remain low to allow adequate forward flow. Eventually, the failing Fontan circulation requires temporary support as the patient awaits a heart transplant. We reviewed PubMed, Google Scholar, and U. Kentucky library for different techniques evaluated to support a failing Fontan circulation.

RESULTS

Multiple technologies have been developed as a bridge to transplant to decrease morbidity. Innovative types of extracorporeal membrane oxygenation, ventricular assist devices, and total artificial hearts have been attempted in laboratory settings as well as in Fontan patients with varying degrees of success. This article emphasizes the strengths and weaknesses of each technology in the context of Fontan physiology.

CONCLUSION

The end game for these patients remains a heart transplant. Without easy access to donors, each of the options discussed is a potential bridge to limit morbidity and mortality until a suitable donor heart becomes available.

The Potential Role of Regenerative Medicine on the Future Management of Hypoplastic Left Heart Syndrome

The development and translation of regenerative medicine approaches for the treatment of hypoplastic left heart syndrome (HLHS) provides a promising alternative to the current standard of care. We review the strategies that have been pursued to date and those that hold the greatest promise in moving forward. Significant challenges remain. Continued scientific advances and technological breakthroughs will be required if we are to translate this technology to the clinic and move from palliative to curative treatment.

MRI Phase-Contrast Blood Flow in Fasting Pediatric Patients with Fontan Circulation Correlates with Exercise Capacity

Purpose

To assess regional blood flow in fasting pediatric patients with Fontan circulation by using MRI and to explore associations with clinical parameters.

Materials and Methods

In this retrospective study, pediatric patients who had undergone the Fontan procedure (<18 years of age) and had undergone clinical cardiac MRI, performed after at least 4 hours of fasting, between 2018 and 2021 were included. Regional blood flow was compared with published healthy volunteer data (n = 19) and assessed in relation to hemodynamic parameters and clinical status. Data are presented as medians, with first to third quartiles in parentheses. Mann-Whitney U, Kruskal-Wallis, χ2, and Spearman rank correlation tests were used.

Results

Fifty-five patients (38 boys) with median age at MRI of 14 years (IQR, 11-16 years) and median time from Fontan procedure to MRI of 10 years (IQR, 8-12 years) were included. Patients after Fontan procedure had lower ascending aortic, inferior vena cava, and total systemic blood flow compared with healthy volunteers (3.00 L/min/m2 [IQR, 2.75-3.30 L/min/m2] vs 3.61 L/min/m2 [IQR, 3.29-4.07 L/min/m2]; 1.73 L/min/m2 [IQR, 1.40-1.94 L/min/m2] vs 2.24 L/min/m2 [IQR, 2.06-2.75 L/min/m2]; 2.78 L/min/m2 [IQR, 2.45-3.10 L/min/m2] vs 3.95 L/min/m2 [IQR, 3.20-4.30 L/min/m2], respectively; P < .001). Portal vein flow was greater than hepatic vein flow in 25% of patients. Fontan blood flow was inversely correlated with pre-Fontan mean pulmonary artery pressure (Spearman rank correlation coefficient [rs ]= -0.42, P = .005) and ventricular end diastolic pressure (rs = -0.33, P = .04) and positively correlated with post-Fontan percent predicted oxygen consumption at peak workload (rs = 0.34, P = .02).

Conclusion

Reference ranges are provided for regional systemic blood flow derived by using MRI in fasting pediatric patients with Fontan circulation, who had lower systemic blood flow compared with healthy volunteers. Lower fasting Fontan blood flow correlated with lower exercise capacity.Keywords: Pediatrics, Heart, Congenital, MR Imaging, Hemodynamics/Flow Dynamics, Cardiac Supplemental material is available for this article. © RSNA, 2022.

The Epidemiology of Persons Living with Fontan in 2020 and Projections for 2030: Development of an Epidemiology Model Providing Multinational Estimates

Introduction

Fontan surgery is a palliative procedure performed in children with a functionally univentricular heart. Improvements in surgical technique over the past 30 years have increased life expectancy in this rare population. However, the epidemiology of persons living with Fontan is poorly understood. This study aimed to estimate the 2020 and 2030 prevalence of persons living with a Fontan circulation in 11 countries across the US, Europe, Australia and New Zealand, by procedure type: [atriopulmonary connection (AP), lateral tunnel total cavopulmonary connection (LT-TCPC) or extracardiac total cavopulmonary connection (EC-TCPC)]; and age group: [children (< 12 years), adolescents (12–17 years), and adults (≥ 18 years old)] by building an epidemiologic model.

Methods

The annual number of Fontan surgeries by country in 2010–2020 were extracted from hospital or claims databases, via procedure codes. The epidemiology of persons living with Fontan was modelled by applying these surgery frequencies to mid-year populations from 1972 to 2020 and overlaying an uptake curve. A literature search identified: 30-day mortality rates, long-term survival, and median age at surgery. Averages of these estimates were inputted into the model to project prevalence in 2030.

Results

The number of persons living with Fontan in 2020 across the 11 countries was estimated to be 47,881 [66 people per million (ppm)], rising to 59,777 (79 ppm) by 2030. In 2020, this population was 55% adults, 17% adolescents and 28% children shifting to 64%, 13% and 23%, respectively, in 2030. Among all persons living with Fontan, 74%/18%/9% are estimated to have EC-TCPC/LT-TCPC/AP, respectively, in 2020, and 83%/14%/4% in 2030.

Conclusions

According to this epidemiology model, the Fontan population is growing, partly driven by increased survival rates with the more recent LT-TCPC and EC-TCPC procedures (compared with AP). The 2020/2030 prevalence of persons living with Fontan is 66/79 ppm.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-02002-3.

Current Treatment Options for the Failing Fontan Circulation

The Fontan operation was introduced in 1968. For congenital malformations, where biventricular repair is unsuitable, the Fontan procedure has provided a long-term palliation strategy with improved outcomes compared to the initially developed procedures. Despite these improvements, several complications merely due to a failing Fontan circulation, including myocardial dysfunction, arrhythmias, increased pulmonary vascular resistance, protein-losing enteropathy, hepatic dysfunction, plastic bronchitis, and thrombo-embolism, may occur, thereby limiting the life-expectancy in this patient cohort. This review provides an overview of the most common complications of Fontan circulation and the currently available treatment options.

Long-term management of Fontan patients: The importance of a multidisciplinary approach

The Fontan operation is a palliative procedure that leads to increased survival of patients with a functional single ventricle (SV). Starting from 1967 when the first operation was performed by Francis Fontan, more and more patients have reached adulthood. Furthermore, it is expected that in the next 20 years, the population with Fontan circulation will reach 150,000 subjects. The absence of right ventricular propulsion and the inability to improve cardiac output because of the low cardiac reserve are the main issues with the Fontan circulation; however, potential complications may also involve multiple organ systems, such as the liver, lungs, brain, bones, and the lymphatic system. As these patients were initially managed mainly by pediatric cardiologists, it was important to assure the appropriate transition to adult care with the involvement of a multidisciplinary team, including adult congenital cardiologists and multiple subspecialists, many of whom are neither yet familiar with the pathophysiology nor the end-organ consequences of the Fontan circulation. Therefore, the aim of our work was to collect all the best available evidence on Fontan's complications management to provide "simple and immediate" information sources for practitioners looking for state of the art evidence to guide their decision-making and work practices. Moreover, we suggest a model of follow-up of patients with Fontan based on a patient-centered multidisciplinary approach.

Miniaturized Fontan Circulation Assist Device: Chronic In Vivo Evaluation

We have miniaturized and optimized our implantable rotary blood pump developed to provide long-term mechanical right heart support for patients who have failing Fontan circulation. The objective of this study was to evaluate the miniaturized Fontan circulation assist device (mini-FCAD) during 30-day sheep studies (n = 5). A complete right heart bypass was performed and all return flow was supported by the pump. Postoperatively, unfractionated heparin was given to maintain thromboelastography R times of 2× normal. The first two studies were terminated on day 0 and day 4 due to complications. In the final three studies, the animals remained healthy and were electively terminated at 30 ± 2 days. Pump flow was between 5 and 7 lpm, left atrial pressure remained normal, and inlet pressures were between 3 and 18 mm Hg with no incidents of suction. There was no evidence of hemolysis, end organ or pulmonary dysfunction, thromboembolic events, nor thermal damage to the surrounding tissue. Explanted devices from two studies were free of thrombi and in the third study there were unattached thrombi on the SVC inlet of the rotor. The mini-FCAD was successfully tested in vivo as a right heart replacement device demonstrating adequate circulatory support and normal physiologic pulmonary and venous pressures.

Engineering Perspective on Cardiovascular Simulations of Fontan Hemodynamics: Where Do We Stand with a Look Towards Clinical Application

BACKGROUND

Cardiovascular simulations for patients with single ventricles undergoing the Fontan procedure can assess patient-specific hemodynamics, explore surgical advances, and develop personalized strategies for surgery and patient care. These simulations have not yet been broadly accepted as a routine clinical tool owing to a number of limitations. Numerous approaches have been explored to seek innovative solutions for improving methodologies and eliminating these limitations.

PURPOSE

This article first reviews the current state of cardiovascular simulations of Fontan hemodynamics. Then, it will discuss the technical progress of Fontan simulations with the emphasis of its clinical impact, noting that substantial improvements have been made in the considerations of patient-specific anatomy, flow, and blood rheology. The article concludes with insights into potential future directions involving clinical validation, uncertainty quantification, and computational efficiency. The advancements in these aspects could promote the clinical usage of Fontan simulations, facilitating its integration into routine clinical practice.

Current Use of Pediatric Cardiac Magnetic Resonance Imaging in Brazil

Fundamento

Dados sobre o uso de ressonância magnética cardíaca (RMC) em crianças no Brasil são escassos.

Objetivos

Buscamos oferecer informações sobre as práticas atuais de RMC pediátricas no Brasil.

Métodos

Um questionário foi enviado a médicos solicitantes de RMC de todo o país, cobrindo informações sobre si próprios, sobre seus serviços de RMC, contexto clínico dos pacientes e sobre os obstáculos para a realização de RMC em crianças. Para a análise estatística, um p < 0,05 bilateral foi considerado significativo.

Resultados

A pesquisa obteve 142 respostas. Foi relatado que a RMC está disponível para 79% dos respondentes, dos quais 52% raramente ou nunca a utilizam. As indicações mais comuns são cardiomiopatias (84%), pós-operatório de correção de tetralogia de Fallot (81%) e malformações do arco aórtico (53%). A complexidade do exame se correlacionou à relação RMC/cirurgia (Rho = 0,48, IC 95% = 0,32-0,62, p < 0,0001) e ao número de exames de RMC (Rho = 0,52, IC 95% = 0,38-0,64, p < 0,0001). A complexidade da RMC esteve associada à sua realização por cardiologistas pediátricos (RC 2,04, IC 95% 1,2-3,89, p < 0,01). Os principais obstáculos ao uso mais frequente de RMC foram o alto custo (65%), a necessidade de sedação (60%) e o número insuficiente de profissionais qualificados (55%).

Conclusão

A RMC pediátrica não é usada frequentemente no Brasil. A presença de um cardiologista pediátrico a frente dos exames esteve associado ao uso de RMC em pacientes mais complexos. O treinamento de especialistas em RMC pediátrica e a educação dos médicos solicitantes são passos importantes na direção de um uso mais abrangente de RMC no Brasil. (Arq Bras Cardiol. 2021; 116(2):305-312)

Dobutamine stress testing for the evaluation of atrial and diastolic ventricular function in Fontan patients

Objective

To assess the atrial and ventricular diastolic function response to dobutamine stress in Fontan patients, and to relate these measurements to exercise capacity and events during the follow-up.

Methods

We performed a secondary analysis of a cross-sectional multicentre study of Fontan patients with intra-atrial lateral tunnel (ILT) or extracardiac conduit (ECC) modification. Subjects underwent cardiac MRI during rest and low-dose dobutamine stress, and cardiopulmonary exercise testing. Atrial and diastolic ventricular function parameters were derived from volume-time curves.

Medical records were abstracted for a composite end-point of death, listing for transplant, arrhythmia and reintervention. Spearman’s r correlation tests and Cox proportional hazards models were used to assess the relation between the dobutamine response for atrial and diastolic ventricular function and outcomes, including exercise capacity.

Results

We included 57 patients (26 ECC; 31 ILT) aged 12.8 (IQR (10.3–15.5)) years. During dobutamine stress atrial cyclic volume change increased (3.0 (0.4–5.9) mL/m², p<0.001), as did early (1.9 (−1.6 to 3.6) mL/m², p=0.001) and late emptying volume (2.2 (0.2–4.4) mL/m², p<0.001).

Ventricular early filling decreased (−1.6 (−5.7 to 0.7) mL/m², p=0.046) and ventricular late filling increased (1.0 (−0.4 to 3.4) mL/m², p<0.001) while stroke volume remained similar.

Only for patients with the ECC modification, atrial early emptying volume increase correlated with peak oxygen uptake (ρ=0.66, p=0.002). No other parameter related to exercise capacity.

During a median 7.1-year follow-up, 22 patients reached the composite endpoint. No parameter predicted events during the follow-up.

Conclusions

Dobutamine stress augmented atrial reservoir and pump function for Fontan patients. Atrial early emptying reserve related to exercise capacity in ECC patients. No other atrial or diastolic ventricular function parameter related to outcomes.

Associations Between Blood Biomarkers, Cardiac Function, and Adverse Outcome in a Young Fontan Cohort

Background Patients who have undergone the Fontan procedure are at high risk of circulatory failure. In an exploratory analysis we aimed to determine the prognostic value of blood biomarkers in a young cohort who have undergone the Fontan procedure. Methods and Results In multicenter prospective studies patients who have undergone the Fontan procedure underwent blood sampling, cardiopulmonary exercise testing, and stress cardiac magnetic resonance imaging. Several biomarkers including NT-proBNP (N-terminal pro-B-type natriuretic peptide), GDF-15 (growth differentiation factor 15), Gal-3 (galectin-3), ST2 (suppression of tumorigenicity 2), DLK-1 (protein delta homolog 1), FABP-4 (fatty acid-binding protein 4), IGFBP-1 (insulin-like growth factor-binding protein 1), IGFBP-7, MMP-2 (matrix metalloproteinase 2), and vWF (von Willebrand factor) were assessed in blood at 9.6 (7.1-12.1) years after Fontan completion. After this baseline study measurement, follow-up information was collected on the incidence of adverse cardiac events, including cardiac death, out of hospital cardiac arrest, heart transplantation (listing), cardiac reintervention (severe events), hospitalization, and cardioversion/ablation for arrhythmias was collected and the relation with blood biomarkers was assessed by Cox proportional hazard analyses. The correlation between biomarkers and other clinical parameters was evaluated. We included 133 patients who have undergone the Fontan procedure, median age 13.2 (25th, 75th percentile 10.4-15.9) years, median age at Fontan 3.2 (2.5-3.9) years. After a median follow-up of 6.2 (4.9-6.9) years, 36 (27.1%) patients experienced an event of whom 13 (9.8%) had a severe event. NT-proBNP was associated with (all) events during follow-up and remained predictive after correction for age, sex, and dominant ventricle (hazard ratio, 1.89; CI, 1.32-2.68). The severe event-free survival was better in patients with low levels of GDF-15 (P=0.005) and vWF (P=0.008) and high levels of DLK-1 (P=0.041). There was a positive correlation (β=0.33, P=0.003) between DLK-1 and stress cardiac magnetic resonance imaging functional reserve. Conclusions NT-proBNP, GDF-15, vWF, DLK-1, ST-2 FABP-4, and IGFBP-7 levels relate to long-term outcome in young patients who have undergone the Fontan procedure.

Relationship of Ventricular Morphology and Atrioventricular Valve Function to Long-Term Outcomes Following Fontan Procedures

BACKGROUND

The influence of ventricular morphology on Fontan outcomes is controversial.

OBJECTIVES

This study hypothesized that dysfunction of the single right ventricle (RV) and right atrioventricular valve regurgitation (AVVR) increases over time and adversely impacts late outcomes following a Fontan operation. A single-center retrospective study was performed.

METHODS

From 1985 through 2018, 1,162 patients underwent the Fontan procedure at our center and were included in this study. Transplant and takedown free survival, ventricular, and atrioventricular valve dysfunction after Fontan were analyzed. Death or heart transplantation information was obtained from the National Death Index and the Scientific Registry of Transplant Recipients.

RESULTS

The follow-up rate was 99%. Morphologic RV was present in 58% of patients. Transplant and takedown free survival were 91%, 75%, and 71% at 10 years, 20 years, and 25 years, respectively. Morphologic RV was an independent risk factor for transplant, takedown free survival (hazard ratio: 2.4; p = 0.008). The AVVR, which preceded ventricular dysfunction in most cases, was associated with the development of ventricular dysfunction after Fontan (odds ratio: 4.3; 95% confidence interval: 2.7 to 6.7; p < 0.001). Furthermore, AVVR and ventricular dysfunction progressed over time after Fontan, especially in the RV (AVVR: p < 0.0001, ventricular dysfunction: p < 0.0001).

CONCLUSIONS

Morphologic RV is negatively associated with the long-term survival following the Fontan, possibly due to a tendency toward progressive AVVR and deterioration of the single ventricle function. Additional volume overload caused by AVVR may be one of the main factors accelerating the dysfunction of the single RV, implying that early valve intervention may be warranted.

Management of Fontan circulation in pregnancy: a multidisciplinary approach to care

The Fontan operation was first performed in 1968 and is a palliative procedure for children born with single ventricle forms of congenital heart disease. Today, 70,000 patients worldwide have Fontan circulation today, half of them women, and with an expected 30-year survival of >80%, this population is expected to double in the next 20 years. The Fontan operation surgically redirects systemic venous blood return directly to the pulmonary circulation, bypassing the single ventricle. This abnormal anatomy results in significant challenges for the cardiovascular system and is marked by a sustained, abnormally elevated systemic venous pressure combined with decreased cardiac output. As more women with Fontan circulation reach childbearing age, understanding the unique risks of pregnancy to the mother and fetus and how to best provide clinical care for these women during pregnancy is imperative. However, there are limited clinical data to guide counseling and management in this population. This expert review offers an analysis of the literature about Fontan circulation during pregnancy and describes our center's current multidisciplinary approach to care for these women in the preconception, antepartum, intrapartum, and postpartum periods.

Target Flow-Pressure Operating Range for Designing a Failing Fontan Cavopulmonary Support Device

Fontan operation as the current standard of care for the palliation of single ventricle defects results in significant late complications. Using a mechanical circulatory device for the right circulation to serve the function of the missing subpulmonary ventricle could potentially stabilize the failing Fontan circulation. This study aims to elucidate the hydraulic operating regions that should be targeted for designing cavopulmonary blood pumps. By integrating numerical analysis and available clinical information, the interaction of the cavopulmonary support via the IVC and full assist configurations with a wide range of simulated adult failing scenarios was investigated; with IVC and full assist corresponding to the inferior venous return or the entire venous return, respectively, being routed through the device. We identified the desired hydraulic operating regions for a cavopulmonary assist device by clustering all head pressures and corresponding pump flows that result in hemodynamic improvement for each simulated failing Fontan physiology. Results show that IVC support can produce beneficial hemodynamics in only a small fraction of failing Fontan scenarios. Cavopulmonary assist device could increase cardiac index by 35% and decrease the inferior vena cava pressure by 45% depending on the patient's pre-support hemodynamic state and surgical configuration of the cavopulmonary assist device (IVC or full support). The desired flow-pressure operating regions we identified can serve as the performance criteria for designing cavopulmonary assist devices as well as evaluating off-label use of commercially available left-side blood pumps for failing Fontan cavopulmonary support.

Focused Update on Pulmonary Hypertension in Children-Selected Topics of Interest for the Adult Cardiologist

Pulmonary hypertensive vascular disease (PHVD), and pulmonary hypertension (PH), which is a broader term, are severe conditions associated with high morbidity and mortality at all ages. Treatment guidelines in childhood are widely adopted from adult data and experience, though big differences may exist regarding aetiology, concomitant conditions and presentation. Over the past few years, paediatric aspects have been incorporated into the common guidelines, which currently address both children and adults with pulmonary hypertension (PH). There are multiple facets of PH in the context of cardiac conditions in childhood. Apart from Eisenmenger syndrome (ES), the broad spectrum of congenital heart disease (CHD) comprises PH in failing Fontan physiology, as well as segmental PH. In this review we provide current data and novel aspects on the pathophysiological background and individual management concepts of these conditions. Moreover, we focus on paediatric left heart failure with PH and its challenging issues, including end stage treatment options, such as mechanical support and paediatric transplantation. PH in the context of rare congenital disorders, such as Scimitar Syndrome and sickle cell disease is discussed. Based on current data, we provide an overview on multiple underlying mechanisms of PH involved in these conditions, and different management strategies in children and adulthood. In addition, we summarize the paediatric aspects and the pros and cons of the recently updated definitions of PH. This review provides deeper insights into some challenging conditions of paediatric PH in order to improve current knowledge and care for children and young adults.

Physical exercise training in patients with a Fontan circulation: A systematic review

BACKGROUND

Patients with a Fontan circulation have a reduced exercise capacity, which is an important prognostic predictor of morbidity and mortality. A way to increase exercise capacity in Fontan patients might be exercise training. This systematic review assesses the effects of exercise training investigated in Fontan patients in order to provide an overview of current insights.

DESIGN AND METHODS

Studies evaluating an exercise training intervention in Fontan patients published up to February 2020 were included in this systematic review.

RESULTS

From 3000 potential studies, 16 studies reported in 22 publications met the inclusion criteria. In total, 264 Fontan patients with mean age range 8.7-31 years, were included. Different training types including inspiratory muscle training, resistance training and aerobic training were investigated. Main outcome measures reported were peak oxygen uptake, cardiac function, lung function, physical activity levels and quality of life. Peak oxygen uptake increased significantly in 56% of the studies after training with an overall mean increase of +1.72 ml/kg/min (+6.3%). None of the studies reported negative outcome measures related to the exercise programme. In four studies an adverse event was reported, most likely unrelated to the training intervention.

CONCLUSIONS

Exercise training in Fontan patients is most likely safe and has positive effects on exercise capacity, cardiac function and quality of life. Therefore exercise training in Fontan patients should be encouraged. Further studies are required to assess the optimal training type, intensity, duration and long-term effects.

Impact of Confounding on Cost, Survival, and Length-of-Stay Outcomes for Neonates with Hypoplastic Left Heart Syndrome Undergoing Stage 1 Palliation Surgery

The objective of this analysis was to update trends in LOS and costs by survivorship and ECMO use among neonates with hypoplastic left heart syndrome (HLHS) undergoing stage 1 palliation surgery using 2016 data from the Healthcare Cost and Utilization Project Kids' Inpatient Database. We identified neonates ≤ 28 days old with HLHS undergoing Stage 1 surgery, defined as a Norwood procedure with modified Blalock-Taussig (BT) shunt, Sano modification, or both. Multivariable regression with year random effects was used to compare LOS and costs by hospital region, case volume, survivorship, and ECMO vs. no ECMO. An E-value analysis, an approach for conducting sensitivity analysis for unmeasured confounding, was performed to determine if unmeasured confounding contributed to the observed effects. Significant differences in total costs, LOS, and mortality were noted by hospital region, ECMO use, and sub-analyses of case volume. However, other than ECMO use and mortality, the maximum E-value confidence interval bound was 1.71, suggesting that these differences would disappear with an unmeasured confounder 1.71 times more associated with both the outcome and exposure (e.g., socioeconomic factors, environment, etc.) Our findings confirm previous literature demonstrating significant resource utilization among Norwood patients, particularly those undergoing ECMO use. Based on our E-value analysis, differences by hospital region and case volume can be explained by moderate unobserved confounding, rather than a reflection of the quality of care provided. Future analyses on surgical quality must account for unobserved factors to provide meaningful information for quality improvement.

Providing a framework of principles for conceptualising the Fontan circulation

The Fontan operation remains the final palliation for thousands of patients with complex congenital heart disease. By creating a Fontan circuit, control of cardiac output and congestion is wrested away from the ventricle and new haemodynamic forces take control. Understanding how to control the flow in the Fontan circuit will enable clinicians to improve patient management and possibly prevent future complications.

Conclusion

This review proposes a framework of principles to conceptualise the functionality and limitations of a Fontan circulation.

What have we learnt 50 years after the first Fontan procedure?

The Fontan procedure is often the only definitive palliative surgical option for patients with a variety of complex CHD sharing in common, a single, dominant ventricle. In recent decades, imaging and therapeutic improvement have played a crucial role in those patients in whom many complications can hamper their life. After 50 years from the first procedure, heart transplantation remains the only definitive treatment for those with a failing Fontan circulation.

Atrial function in Fontan patients assessed by CMR: Relation with exercise capacity and long-term outcomes

OBJECTIVE

To assess the role of atrial function on exercise capacity and clinical events in Fontan patients.

DESIGN

We included 96 Fontan patients from 6 tertiary centers, aged 12.8 (IQR 10.1-15.6) years, who underwent cardiac magnetic resonance imaging and cardiopulmonary exercise testing within 12 months of each other from 2004 to 2017. Intra-atrial lateral tunnel (ILT) and extracardiac conduit (ECC) patients were matched 1:1 with regard to age, gender and dominant ventricle. The pulmonary venous atrium was manually segmented in all phases and slices. Atrial function was assessed by volume-time curves. Furthermore, atrial longitudinal and circumferential feature tracking strain was assessed. We determined the relation between atrial function and exercise capacity, assessed by peak oxygen uptake and VE/VCO₂ slope, and events (mortality, listing for transplant, re-intervention, arrhythmia) during follow-up.

RESULTS

Atrial maximal and minimal volumes did not differ between ILT and ECC patients. ECC patients had higher reservoir function (21.1 [16.4-28.0]% vs 18.2 [10.9-22.2]%, p = .03), lower conduit function and lower total circumferential strain (13.8 ± 5.1% vs 18.0 ± 8.7%, p = .01), compared to ILT patients. Only for ECC patients, a better late peak circumferential strain rate predicted better VE/VCO₂ slope. No other parameter of atrial function predicted peak oxygen uptake or VE/VCO₂ slope. During a median follow-up of 6.2 years, 42 patients reached the composite end-point. No atrial function parameters predicted events during follow-up.

CONCLUSIONS

ECC patients have higher atrial reservoir function and lower conduit function. Atrial function did not predict exercise capacity or events during follow-up.

Staged total cavopulmonary connection: serial comparison of intra-atrial lateral tunnel and extracardiac conduit taking account of current surgical adaptations

OBJECTIVES

Our goals were to compare the outcome of the intra-atrial lateral tunnel (ILT) and the extracardiac conduit (ECC) techniques for staged total cavopulmonary connection (TCPC) and to compare the current modifications of the TCPC technique, i.e. the prosthetic ILT technique with the current ECC technique with a ≥18-mm conduit.

METHODS

We included patients who had undergone a staged TCPC between 1988 and 2008. Records were reviewed for patient demographics, operative details and events during follow-up (death, surgical and catheter-based reinterventions and arrhythmias).

RESULTS

Of the 208 patients included, 103 had the ILT (51 baffle, 52 prosthetic) technique and 105 had the ECC technique. Median follow-up duration was 13.2 years (interquartile range 9.5-16.3). At 15 years after the TCPC, the overall survival rate was comparable (81% ILT vs 89% ECC; P = 0.12). Freedom from late surgical and catheter-based reintervention was higher for patients who had ILT than for those who had ECC (63% vs 44%; P = 0.016). However, freedom from late arrhythmia was lower for patients who had ILT than for those who had ECC (71% vs 85%, P = 0.034). In a subgroup of patients who had the current TCPC technique, when we compared the use of a prosthetic ILT with ≥18-mm ECC, we found no differences in freedom from late arrhythmias (82% vs 86%, P = 0.64) or in freedom from late reinterventions (70% vs 52%, P = 0.14).

CONCLUSIONS

A comparison between the updated prosthetic ILT and current ≥18-mm ECC techniques revealed no differences in late arrhythmia-free survival or late reintervention-free survival. Overall, outcomes after the staged TCPC were relatively good and reinterventions occurred more frequently in the ECC group, whereas late arrhythmias were more common in the ILT group.

Variation in care for children undergoing the Fontan operation for hypoplastic left heart syndrome

BACKGROUND

The Single Ventricle Reconstruction Trial randomised neonates with hypoplastic left heart syndrome to a shunt strategy but otherwise retained standard of care. We aimed to describe centre-level practice variation at Fontan completion.

METHODS

Centre-level data are reported as median or median frequency across all centres and range of medians or frequencies across centres. Classification and regression tree analysis assessed the association of centre-level factors with length of stay and percentage of patients with prolonged pleural effusion (>7 days).

RESULTS

The median Fontan age (14 centres, 320 patients) was 3.1 years (range from 1.7 to 3.9), and the weight-for-age z-score was -0.56 (-1.35 + 0.44). Extra-cardiac Fontans were performed in 79% (4-100%) of patients at the 13 centres performing this procedure; lateral tunnels were performed in 32% (3-100%) at the 11 centres performing it. Deep hypothermic circulatory arrest (nine centres) ranged from 6 to 100%. Major complications occurred in 17% (7-33%). The length of stay was 9.5 days (9-12); 15% (6-33%) had prolonged pleural effusion. Centres with fewer patients (<6%) with prolonged pleural effusion and fewer (<41%) complications had a shorter length of stay (<10 days; sensitivity 1.0; specificity 0.71; area under the curve 0.96). Avoiding deep hypothermic circulatory arrest and higher weight-for-age z-score were associated with a lower percentage of patients with prolonged effusions (<9.5%; sensitivity 1.0; specificity = 0.86; area under the curve 0.98).

CONCLUSIONS

Fontan perioperative practices varied widely among study centres. Strategies to decrease the duration of pleural effusion and minimise complications may decrease the length of stay. Further research regarding deep hypothermic circulatory arrest is needed to understand its association with prolonged pleural effusion.

Risk Factors for Prolonged Pleural Effusion Following Total Cavopulmonary Connection Surgery: 9 Years' Experience at Fuwai Hospital

Background: Prolonged pleural effusion (PPE) contributes to adverse outcomes after total cavopulmonary connection (TCPC) completion. We aimed to identify risk factors for PPE following TCPC surgery. Methods: We studied a retrospective cohort of 525 who undergoing TCPC surgery from 2010 to 2019. We defined PPE as the duration of pleural effusion exceeding 14 days. Logistic regression was applied to identify risk factors for PPE and Cox regression was used to identify risk factors for predicting the duration of pleural effusion. The impacts of PPE on the short-term outcomes were evaluated. Results: The rate of PPE was 27.4% in our study and independent risk factors for PPE included: young age, no fenestration, low postoperative total protein, prolonged mechanical ventilation and chylothorax. These predictors were also achieved in the Cox regression for predicting the duration of pleural effusion. The applicability of the model was acceptable in different subgroups, which derived from the total cohort. Patients with PPE were associated with more renal replacement treatment, longer length of ICU and hospital stay, more hospitalization costs and a higher rate of in-hospital mortality. Conclusions: PPE in our study occurs at a relatively lower rate than that reported in previous studies and patients with PPE was associated with higher rate of in-hospital mortality when compared to patients without PPE. Young age, no fenestration, low postoperative total protein, prolonged mechanical ventilation, and chylothorax were identified as independent risk factors to predict PPE. A preventive strategy that targets the identified risk factors to reduce the incidence of PPE following TCPC surgery could be beneficial for in-hospital outcomes, and the model needs further validation before its application.

[Non-cardiac surgery in adults with congenital heart defects : Most important parameters in anesthesia management]

BACKGROUND

Adults with congenital heart disease (CHD) represent an increasing proportion of patients undergoing non-cardiac surgery.

OBJECTIVE

To identify the most important parameters for management of anesthesia.

MATERIAL AND METHODS

Evaluation and discussion of the current original research and guideline recommendations.

RESULTS

There are approximately 300,000 patients with CHD living in Germany. The preoperative evaluation is an important influencing factor affecting perioperative morbidity and mortality. Echocardiography is the key instrument for identifying cardiac conditions predisposing to adverse events. The subdivision of CHD into lesions with left-to-right shunt, obstructive lesions and complex congenital heart diseases facilitates the classification of the pathophysiology.

CONCLUSION

Decisive for the perioperative outcome of patients with CHD are the identification of high-risk patients, understanding of the individual situation with respect to the underlying pathophysiology and the intraoperative maintenance of cardiac output.

Oxygen Availability in Respiratory Muscles During Exercise in Children Following Fontan Operation

Introduction: As survival of previously considered as lethal congenital heart disease forms is the case in our days, issues regarding quality of life including sport and daily activities emerge. In patients with Fontan circulation, there is no pump to propel blood into the pulmonary arteries since the systemic veins are directly connected to the pulmonary arteries. The complex hemodynamics of Fontan circulation include atrial function, peripheral muscle pump, integrity of the atrioventricular valve, absence of restrictive, or obstructive pulmonary lung function. Therefore, thoracic mechanics are of particular importance within the complex hemodynamics of Fontan circulation. Methods: To understand the physiology of respiratory muscles, the aim of this study was to examine the matching of auxiliary respiratory muscle oxygen delivery and utilization during incremental exercise in young male Fontan patients (n = 22, age = 12.04 ± 2.51) and healthy Controls (n = 10, age = 14.90 ± 2.23). All subjects underwent a cardiopulmonary exercise test (CPET) to exhaustion whereas respiratory muscle oxygenation was measured non-invasively using a near-infrared spectrometer (NIRS). Results: CPET revealed significantly lower peak power output, oxygen uptake and breath activity in Fontan patients. The onset of respiratory muscle deoxygenation was significantly earlier. The matching of local muscle perfusion to oxygen demand was significantly worse in Fontans between 50 and 90% V . O 2 peak . Findings: The results indicate that (a) there is high strain on respiratory muscles during incremental cycling exercise and (b) auxiliary respiratory muscles are worse perfused in patients who underwent a Fontan procedure compared to healthy Controls. This might be indicative of a more general skeletal muscle strain and worse perfusion in Fontan patients rather than a localized-limited to thoracic muscles phenomenon.