Venovenous collaterals are abnormal connections between the systemic and pulmonary venous systems. They are commonly seen in the Fontan circulation and may lead to significant hypoxaemia. Transcatheter closure of venovenous collaterals is a potential but controversial treatment as the long-term benefits and outcomes are not well understood.

This retrospective cohort study utilised data from the Australian and New Zealand Fontan Registry. Patients who underwent transcatheter venovenous collateral occlusion for hypoxemia from the year 2000 onwards were included. Atriopulmonary and Kawashima-type Fontan circulations were excluded to reflect a more contemporary Fontan cohort.

Nineteen patients (age 19.3 ± 7.8 years, 53% female) underwent transcatheter venovenous collateral occlusion. Compared to baseline, mean oxygen saturation was improved at latest follow-up (90.5% vs 87.0%; p = 0.003). Nine patients achieved a clinically significant response (defined as an increase of at least 5% to 90% or greater), and this was associated with lower baseline Fontan pressures (12.9 v 15.6 mmHg; p = 0.02). No heart failure hospitalisations, arrhythmia, transplant referrals, or mortality were observed during the median follow-up period of 4 years. Two patients experienced thromboembolic events and five patients underwent re-intervention.

Transcatheter occlusion of venovenous collaterals in Fontan patients with chronic hypoxaemia resulted in a modest increase in oxygenation over a median follow-up of 4 years and longer-term prognosis did not appear to be adversely affected. Lower Fontan pressures at baseline were associated with a greater improvement in oxygenation.

Haemodynamic changes in caval venous flow distribution occurring during bidirectional cavopulmonary anastomosis operation are still largely unknown.

Transit time flow measurements were performed in 15 cavopulmonary anastomosis operations. Superior and inferior caval vein flows were measured before and after the cavopulmonary anastomosis. Ratio of superior caval vein to overall caval veins flow was calculated.

Mean superior caval vein flow ratio before cavopulmonary anastomosis was higher than previously reported for healthy children. Superior caval vein flow ratio decreased in 14/15 patients after cavopulmonary anastomosis: mean 0.63 ± 0.12 before versus 0.43 ± 0.14 after. No linear correlation between intraoperative superior caval vein pressure and superior caval vein flow after cavopulmonary anastomosis was found. Neither Nakata index nor pulmonary vascular resistance measured at preoperative cardiac catheterisation correlated with intraoperative flows. None of patients died or required a take down.

The higher mean superior caval vein flow ratio before cavopulmonary anastomosis compared to healthy children suggests flow redistribution in univentricular physiology to protect brain and neurodevelopment. The decrease of superior caval vein flow ratio after cavopulmonary anastomosis may reflect the flow redistribution related to trans-pulmonary gradient. The lack of correlation between superior caval vein pressure and superior caval vein flow could be explained by limited sample size and multifactorial determinants of caval veins flow, although pressure remain essential. Larger sample of measurements are needed to find flow range potentially predictive for clinical failure. To authors’ knowledge, this is the first intraoperative flow measurement of both caval veins during cavopulmonary operations.

The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool.

PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried.

A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions.

Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

Little data are available concerning the methods used in the long-term follow-up of Fontan patients. We analyzed the association between serum N-terminal pro-brain natriuretic peptide levels, conventional echocardiography findings, exercise parameters, and dyssynchrony measurements in patients who underwent Fontan surgery.

This study included 28 patients who underwent Fontan surgery (mean age 12.8 ± 4.36 years) and 27 healthy controls (mean age 12.5 ± 3.76 years). Echocardiography examinations and exercise tests were performed in both groups. The systemic ventricle was examined via echocardiography, dyssynchrony measurement was performed, the systemic ventricular myocardial performance index was calculated, and serum N-terminal pro-brain natriuretic peptide levels were measured for all subjects.

Lower cardiac output, stroke volume, maximal work, chronotropic index, maximal oxygen uptake, and higher N-terminal pro-brain natriuretic peptide levels were observed in the Fontan group than in the control group (p < 0.05). A negative correlation was found between physical exercise parameters and N-terminal pro-brain natriuretic peptide levels and dyssynchrony measurements.

Measurements of exercise capacity, serum N-terminal pro-brain natriuretic peptide levels, and dyssynchrony measurement were more valuable than conventional methods for assessing patients’ clinical and functional status. Dyssynchrony measurements provided better information about ventricular status than did conventional echocardiography studies. While patients’ systolic function determined by conventional echocardiography was normal, dyssynchrony measurements showed the opposite result. The negative relationship between serum N-terminal pro-brain natriuretic peptide levels, dyssynchrony measurements, and exercise capacity suggests that these parameters should be investigated further in Fontan patients.

To investigate quality of life and mental health after Fontan completion, we aimed to characterise outcomes in a representative group of adolescent patients. The study was part of the pre-transition clinical work-up in adolescents with Fontan-type palliation of univentricular CHD. The programme covers the entire paediatric Fontan patient population in Norway.

Our cross-sectional study included 42 adolescents with Fontan circulation aged 15–18. We recruited a control group of 29 healthy peers. Quality of life was measured by the Pediatric Quality of Life Inventory Questionnaire, while mental health was assessed with the Strength and Difficulties Questionnaire.

Fontan patients scored lower than healthy controls on the Pediatric Quality of Life Inventory total (p = 0.004), the physical (p < 0.001) and social (p = 0.001) functioning subscale, and the Strength and Difficulties Questionnaire subscale of emotional symptoms (p = 0.035). Compared to two of the healthy teens (7%), seven patients (16%) in the Fontan group scored as having impaired mental health (p = 0.224). The female/male ratio for individuals with impaired health was 7:2 (p = 0.003).

Compared to healthy controls, adolescents after Fontan-type palliation in Norway have good health-related quality of life and mental health, despite having slightly lower score than healthy individuals, mainly in physical domains and school functioning. Compared to healthy controls and healthy teenagers, these adolescents have somewhat more emotional problems, and compared to male patients, female patients more often have impaired mental health.

Young patients with Fontan circulation may have low serum 25-hydroxyvitamin D levels, an affected liver, and unhealthy body compositions. This study aimed to explore the association between vitamin D intake/levels, liver biomarkers, and body composition in young Fontan patients.

We collected prospective data in 2017 to 2018, obtained with food-frequency questionnaires, biochemical analyses of liver biomarkers, and dual-energy X-ray absorptiometry scans in 44 children with Fontan circulation. Body compositions were compared to matched controls (n = 38). Linear regression analyses were used to investigate associations of biomarkers, leg pain, and lean mass on serum levels of 25-hydroxyvitamin D. Biomarkers were converted to z scores and differences were evaluated within the Fontan patients.

Our Fontan patients had a daily mean vitamin D intake of 9.9 µg and a mean serum 25-hydroxyvitamin D of 56 nmol/L. These factors were not associated with fat or lean mass, leg pain, or biomarkers of liver status. The Fontan patients had significantly less lean mass, but higher fat mass than controls. Male adolescents with Fontan circulation had a greater mean abdominal fat mass than male controls and higher cholesterol levels than females with Fontan circulation.

Vitamin D intake and serum levels were not associated with body composition or liver biomarkers in the Fontan group, but the Fontan group had lower lean mass and higher fat mass than controls. The more pronounced abdominal fat mass in male adolescents with Fontan circulation might increase metabolic risks later in life.

Progress in the management of complex congenital heart disease (CHD) led to an improvement in survival rates of adults with a Fontan-like circulation. The objective of this study was to assess the subjective health status and quality of life of this population.

Patients aged more than 18 years at the time of the study, who underwent a Fontan-like procedure. Subjective health status was assessed by the SF-36 questionnaire and a linear analog scale was used to score patients’ self-perception of their quality of life; cardiac and demographic parameters were collected.

Among 65 eligible patients, 60 (23 females; mean ± SD age: 25.7 ± 7.2 years) answered the SF-36 questionnaire and 46 of these were interviewed to evaluate their perceived quality of life. Among them, 20 (33.3%) were working full-time and 21 (35%) experienced arrhythmias. The physical SF-36 scores were lower in patients than in the general population (p ≤ 0.05). The New York Hear Association (NYHA) class and occupation were correlated with SF-36 scores of physical activity (respectively, p = 0.0001 and p = 0.025). SF-36 scores of psychological status were associated with the number of drugs and occupation (respectively, p = 0.0001 and p = 0.02). The mean ± SD quality of life score measured using a linear analog scale was 7.02 ± 1.6 and was linked to education and occupation (p ≤ 0.05) but not with cardiac parameters.

Adult Fontan patients perceive an impaired physical health but report a good overall quality of life. Education and occupation impacts significantly on Fontan patients’ quality of life.

Impaired isometric muscle strength was previously reported in adults with Fontan circulation. However, it is unclear if this impairment is present in children and adolescents with Fontan circulation. We investigated isometric muscle strength of the lower limb in patients (6–18 years) with Fontan circulation in comparison with healthy controls.

In this cross-sectional study, 43 patients (6–18 years) with Fontan circulation and 43 age- and sex-matched controls were included. Isometric knee extension and plantar flexion muscle strength were assessed using dynamometry (Newton, N). Lean mass of the legs was assessed with dual-energy X-ray absorptiometry. Analyses were performed on group level (n = 43), and for subgroups that included children aged 6–12 years (n = 18) and adolescents aged 13–18 years (n = 25).

On group level, the patients with Fontan circulation had impaired isometric knee extension strength in comparison with the controls (p = 0.03). In subgroup analyses, impaired isometric knee extension strength was present in the adolescents (p = 0.009) but not in the children groups. For plantar flexion, there was no difference between patients and controls. There was no difference in lean mass between patients and controls (9.6 ± 4.3 kg vs. 10.8 ± 5.6 kg, p = 0.31). However, the lean mass was highly correlated to isometric knee extension strength (patients r = 0.89, controls r = 0.96, p < 0.001) and isometric plantar flexion strength (patients r = 0.7, controls r = 0.81, p < 0.001).

The finding of impaired isometric knee extension muscle strength in adolescents (13–18 years) with Fontan circulation and no corresponding impairment in the children group (6–12 years) could imply that isometric muscle strength gets more impaired with age.

This is a cross-sectional study aiming to understand the early characteristics and background of bone health impairment in clinically well children with Fontan circulation.

We enrolled 10 clinically well children with Fontan palliation (operated >5 years before study entrance, Tanner stage ≤3, age 12.1 ± 1.77 years, 7 males) and 11 healthy controls (age 12.0 ± 1.45 years, 9 males) at two children’s hospitals. All patients underwent peripheral quantitative CT. For the Fontan group, we obtained clinical characteristics, NYHA class, cardiac index by MRI, dual x-ray absorptiometry, and biochemical studies. Linear regression was used to compare radius and tibia peripheral quantitative CT measures between Fontan patients and controls.

All Fontan patients were clinically well (NYHA class 1 or 2, cardiac index 4.85 ± 1.51 L/min/m2) and without significant comorbidities. Adjusted trabecular bone mineral density, cortical thickness, and bone strength index at the radius were significantly decreased in Fontan patients compared to controls with mean differences −30.13 mg/cm3 (p = 0.041), −0.31 mm (p = 0.043), and −6.65 mg2/mm4 (p = 0.036), respectively. No differences were found for tibial measures. In Fontan patients, the mean height-adjusted lumbar bone mineral density and total body less head z scores were −0.46 ± 1.1 and −0.63 ± 1.1, respectively, which are below the average, but within normal range for age and sex.

In a clinically well Fontan cohort, we found significant bone deficits by peripheral quantitative CT in the radius but not the tibia, suggesting non-weight-bearing bones may be more vulnerable to the unique haemodynamics of the Fontan circulation.

To bring together stakeholders in the United Kingdom to establish national priorities for research in single-ventricle heart conditions.

This study comprised two surveys and a workshop. The initial public online survey asked respondents up to three questions they would like answered for research. Responses were classified as unanswered, already answered, or unable to be answered by scientific research. In the follow-up survey, unanswered questions were divided into categories and respondents were asked to rank categories and questions by priority. A stakeholder workshop attended by patients, parents, healthcare professionals, researchers, and charities was held to determine the final list of research priorities.

A total of 128 respondents posed 344 research questions, of which 271 were classified as unanswered, and after removing duplicates, 204 questions remained, which were divided into 20 categories. In the second survey, 56 (49.1%) respondents successfully ranked categories and questions. A total of 39 participants attended the workshop, drawing up a list of 30 research priorities across nine priority categories. The nine priority categories are: Associated co-morbidities; Brain & neurodevelopment; Exercise; Fontan failure; Heart function; Living with a single ventricle heart condition; Management of the well-functioning Fontan circulation; Surgery & perioperative care; and Transplantation, mechanical support & novel therapies.

Through a multi-stage process, we engaged a wide range of interested parties to establish a list of research priorities in single-ventricle heart conditions. This provides a platform for clinicians, researchers, and funders in the United Kingdom and elsewhere to address the most important questions and improve outcomes in these rare but high-impact CHDs.

The Fontan circulation is the optimal treatment for patients with univentricular hearts. These patients are at high risk of circulatory failure. There is no consensus on the optimal drug treatment for the prevention of failure of the Fontan circulation. The aim of this systematic review was to provide an overview of evidence for drug therapy used in the prevention of Fontan circulatory failure.

We searched the Embase database for articles that reported drug therapy in Fontan patients. Studies published between 1997 and 2014 were included if efficacy or safety of medication was assessed, drug therapy aimed to prevent or treat failure of the Fontan circulation, and if the full text was available. Case reports were excluded.

A total of nine studies were included with a total of 267 Fontan patients; four studies evaluated the medication sildenafil, one iloprost, three bosentan, and one enalapril. Among all, two sildenafil studies reported improvement in exercise capacity, one in exercise haemodynamics, and one in ventricular performance. In the largest study of bosentan, an increase in exercise capacity was found. Enalapril did not result in improvements.

The studies analysed in this review suggest that bosentan, sildenafil, and iloprost may improve exercise capacity at the short term. Given the limitations of the studies, more, larger, placebo-controlled studies with longer follow-up periods are needed to better understand which drug therapies are effective in the prevention of failure of the Fontan circulation.

It is important to identify those children with a Fontan circulation who are at risk for impaired health-related quality of life. We aimed to determine the predictive value of functional health status – medical history and present medical status – on both physical and psychosocial domains of health-related quality of life, as reported by patients themselves and their parents.

We carried out a prospective cross-sectional multi-centre study in Fontan patients aged between 8 and 15, who had undergone staged completion of total cavopulmonary connection according to a current technique before the age of 7 years.

Functional health status was assessed as medical history – that is, age at Fontan, type of Fontan, ventricular dominance, and number of cardiac surgical procedures – and present medical status – assessed with magnetic resonance imaging, exercise testing, and rhythm assessment. Health-related quality of life was assessed with The TNO/AZL Child Questionnaire Child Form and Parent Form.

In multivariate prediction models, several medical history variables, such as more operations post-Fontan completion, lower age at Fontan completion, and dominant right ventricle, and present medical status variables, such as smaller end-diastolic volume, a higher score for ventilatory efficiency, and the presence of sinus node dysfunction, predicted worse outcomes on several parent-reported and self-reported physical as well as psychosocial health-related quality of life domains.

Medical history and worse present medical status not only predicted worse physical parent-reported and self-reported health-related quality of life but also worse psychosocial health-related quality of life and subjective cognitive functioning. These findings will help in identifying patients who are at risk for developing impaired health-related quality of life.