The functional roles of ventricular dominance and additional ventricular chamber after Fontan operation are still uncertain. We aim to assess and correlate such anatomical features to late clinical outcomes.

Fontan patients undergoing cardiac MRI and cardiopulmonary exercise test between January 2020 and December 2022 were retrospectively reviewed. Clinical, cardiac MRI, and cardiopulmonary exercise test data from the last follow-up were analysed.

Fifty patients were analysed: left dominance was present in 29 patients (58%, median age 20 years, interquartile range:16–26). At a median follow-up after the Fontan operation was 16 years (interquartile range: 4–42), NYHA classes III and IV was present in 3 patients (6%), 4 (8%) underwent Fontan conversion, 2 (4%) were listed for heart transplantation, and 2 (4%) died. Statistical analysis showed that the additional ventricular chamber was larger (>20 mL/m2) in patients with a right dominant ventricle (p = 0.01), and right dominance was associated with a higher incidence of post-operative low-cardiac output syndrome (p = 0.043). Left ventricular dominance was associated with a better ejection fraction (p = 0.04), less extent of late gadolinium enhancement (p = 0.022), higher metabolic equivalents (p = 0.01), and higher peak oxygen consumption (p = 0.033). A larger additional ventricular chamber was associated with a higher need for post-operative extracorporeal membrane oxygenation support (p = 0.007), but it did not influence functional parameters on cardiac MRI or cardiopulmonary exercise test.

In Fontan patients, left ventricular dominance correlated to better functional outcomes. Conversely, a larger additional ventricular chamber is more frequent in right ventricular dominance and can negatively affect the early post-Fontan course.

Emerging evidence suggests that routine physical activity may improve exercise capacity, long-term outcomes, and quality of life in individuals with Fontan circulation. Despite this, it is unclear how active these individuals are and what guidance they receive from medical providers regarding physical activity. The aim of this study was to survey Fontan patients on personal physical activity behaviours and their cardiologist-directed physical activity recommendations to set a baseline for future targeted efforts to improve this.

An electronic survey assessing physical activity habits and cardiologist-directed guidance was developed in concert with content experts and patients/parents and shared via a social media campaign with Fontan patients and their families.

A total of 168 individuals completed the survey. The median age of respondents was 10 years, 51% identifying as male. Overall, 21% of respondents spend > 5 hours per week engaged in low-exertion activity and only 7% spend > 5 hours per week engaged in high-exertion activity. In all domains questioned, pre-adolescents reported higher participation rates than adolescents. Nearly half (43%) of respondents reported that they do not discuss activity recommendations with their cardiologist.

Despite increasing evidence over the last two decades demonstrating the benefit of exercise for individuals living with Fontan circulation, only a minority of patients report engaging in significant amounts of physical activity or discussing activity goals with their cardiologist. Specific, individualized, and actionable education needs to be provided to patients, families, and providers to promote and support regular physical activity in this patient population.

The time constant of isovolumic relaxation is an established index of ventricular relaxation, a major component of diastolic function, even in a single right ventricle. However, the specific echocardiographic parameters for estimating diastolic dysfunction are insufficient for a single right ventricle. This study aimed to investigate the echocardiographic indices associated with time constant of isovolumic relaxation in post-Fontan operation patients with a single right ventricle.

We included 39 patients with hypoplastic left heart syndrome after Fontan operation with an ejection fraction ≥45% and preserved valve function. First, the correlation between echocardiographic parameters and time constant of isovolumic relaxation was examined, and partial correlation coefficients were calculated using age and heart rate as covariates. Next, univariate regression analysis was performed using time constant of isovolumic relaxation as the objective variable and echocardiographic parameters as independent variables, followed by multivariate regression analysis incorporating parameters with p < 0.10.

Among the echocardiographic parameters, global longitudinal strain correlated most strongly with time constant of isovolumic relaxation (r = 0.778, p < 0.001). This was consistent with the partial correlation coefficients (r = 0.707, p < 0.001). Using stepwise multivariate regression analysis, only global longitudinal strain was found to be an independent predictor of time constant of isovolumic relaxation (adjusted R2 = 0.551).

Global longitudinal strain could be used as a surrogate marker of time constant of isovolumic relaxation, an invasive indicator of relaxation impairment, in post-Fontan operation patients with a single right ventricle, preserved ejection fraction, and valve function.

Complications following the Fontan procedure include prolonged pleural drainage and readmission for effusions. To address these complications, a post-Fontan management pathway was implemented with primary goals of reducing chest tube duration/reinsertion rates and decreasing hospital length of stay and readmissions.

Fontan patients were identified by retrospective chart review (2017–2019) to obtain baseline data for chest tube duration/reinsertion rates, hospital length of stay, and readmission rates for effusion. A post-Fontan management pathway was implemented (2020–2021) utilising post-operative vasopressin, nasal cannula oxygen until chest tube removal, and discharge regimen of three times daily diuretics, sildenafil, and afterload reducing medications. Patients were followed to evaluate primary outcomes.

The pre- and post-pathway groups were similar in single ventricle morphology, demographics, and pre-operative haemodynamics. Forty-three and 36 patients were included in the pre- and post-pathway cohorts, respectively. There were statistically significant reductions in chest tube duration (8 vs. 5 days, p ≤ 0.001), chest tube output on post-operative day 4 (20.4 vs. 9.9 mL/kg/day, p = 0.003), and hospital readmission rates for effusion (13[30%] vs. 3[8%], p = 0.02) compared to baseline. There was an absolute reduction in hospital length of stay (11 vs. 9.5 days, p = 0.052). When combining average cost savings for the Fontan hospitalisations, readmissions for effusion, and cardiac catheterisations within 6 months of Fontan completion, there was a $325,144 total cost savings for 36 patients following pathway implementation.

Implementation of a post-Fontan management pathway resulted in significant reductions in chest tube duration and output, and readmission rates for effusion in the perioperative period.

Children with CHD develop heart failure due to increased pulmonary blood flow, cyanosis, and pulmonary hypertension. The metabolic needs of these children differ from those of healthy children, and malnutrition is common. Protein-losing enteropathy has been reported in 5 to 13% of patients after the Fontan procedure. Serum albumin and total protein levels, which are indicators of the quality of post-operative care, can be useful tools for monitoring and examining the intensive care treatment strategies of these patients. In our retrospective study, the effects of albumin and total protein values, which are two of the markers that give us an idea about diet, nutritional status, and inflammation, on the prognosis of children who underwent the Fontan procedure were investigated.

In our study, 127 patients who underwent Fontan procedure in our clinic between 2012 and 2021 were analysed retrospectively. Of the patients, 52.7% (n = 67) were male and 47.3% (n = 60) were female. The mean age is 5.83 ± 4.63 years. Patients who underwent albumin replacement were not included in the study.

Although the relationship between pre-operative albumin and total protein values and post-operative mortality was not statistically significant, the inverse correlation of post-operative albumin 1st, 2nd, and 3rd-day values and post-operative total protein 1st, 2nd, and 3rd-day values with mortality was found to be statistically significant. In addition, we found that mortality was statistically high in patients whose total protein amount was below 6.65 mg/dl in the early post-operative period.

Albumin and total protein, whose blood levels can vary with diet, can be used as predictors in the early post-operative prognosis of Fontan patients. In addition, when we examined the exitus patients, it was observed that the total protein amount was below 6.65 mg/dl on the post-operative 1st day. Based on this, we think that a diet with high protein content before surgery will help reduce post-operative early mortality.

The cardiovascular adaptations associated with structured exercise training in Fontan patients remain unknown. We hypothesised that short-term training causes cardiac remodelling and parallel improvement in maximal exercise capacity (VO2 max) in these patients.

Five patients, median age 19.5 (17.6–21.3) years, with a history of Fontan operation meeting inclusion/exclusion criteria, participated in a 3-month training programme designed to improve endurance. Magnetic resonance images for assessment of cardiac function, fibrosis, cardiac output, and liver elastography to assess stiffness were obtained at baseline and after training. Maximal exercise capacity (VO2 max) and cardiac output Qc (effective pulmonary blood flow) at rest and during exercise were measured (C2H2 rebreathing) at the same interval. VO2 max increased from median (IQR) 27.2 (26–28.7) to 29.6 (28.5–32.2) ml/min/kg (p = 0.04). There was an improvement in cardiac output (Qc) during maximal exercise testing from median (IQR) 10.3 (10.1–12.3) to 12.3 (10.9–14.9) l/min, but this change was variable (p = 0.14). Improvement in VO2 max correlated with an increase in ventricular mass (r = 0.95, p = 0.01), and improvement in Quality-of-life inventory (PedsQL) Cardiac scale scores for patient-reported symptoms (r = 0.90, p = 0.03) and cognitive problems (r = 0.89, p = 0.04). The correlation between VO2 max and Qc showed a positive trend but was not significant (r = 0.8, p = 0.08). No adverse cardiac or liver adaptations were noted.

Short-term training improved exercise capacity in this Fontan pilot without any adverse cardiac or liver adaptations. These results warrant further study in a larger population and over a longer duration of time.

NCT03263312, Unique Protocol ID: STU 122016-037; Registration Date: 18 January, 2017.

This study investigated the association between early extubation (EE) and the degree of postoperative intensive care unit (ICU) support after the Fontan procedure, specifically evaluating the volume of postoperative intravenous fluid (IVF) and vasoactive-inotropic score (VIS).

Retrospective analysis of patients who underwent Fontan palliation from 2008 to 2018 at a single center was completed. Patients were initially divided into pre-institutional initiative towards EE (control) and post-initiative (modern) cohorts. Differences between the cohorts were assessed using t-test, Wilcoxon, or chi-Square. Following stratification by early or late extubation, four groups were compared via ANOVA or Kruskal-Wallis Test.

There was a significant difference in the rate of EE between the control and modern cohorts (mean 42.6 versus 75.7%, p = 0.01). The modern cohort demonstrated lower median VIS (5 versus 8, p = 0.002), but higher total mean IVF (101±42 versus 82 ±27 cc/kg, p < 0.001) versus control cohort. Late extubated (LE) patients in the modern cohort had the highest VIS and IVF requirements. This group received 67% more IVF (140 ± 53 versus 84 ± 26 cc/kg, p < 0.001) and had a higher median VIS at 24 hours (10 (IQR, 5–10) versus 4 (IQR, 2–7), p < 0.001) versus all other groups. In comparison, all EE patients had a 5-point lower median VIS when compared to LE patients (3 versus 8, p= 0.001).

EE following the Fontan procedure is associated with reduced post-operative VIS. LE patients in the modern cohort received more IVF, potentially identifying a high-risk subgroup of Fontan patients deserving of further investigation.

Patients with Fontan physiology require non-cardiac surgery. Our objectives were to characterise perioperative outcomes of patients with Fontan physiology undergoing non-cardiac surgery and to identify characteristics which predict discharge on the same day.

Children and young adults with Fontan physiology who underwent a non-cardiac surgery or an imaging study under anaesthesia between 2013 and 2019 at a single-centre academic children’s hospital were reviewed in a retrospective observational study. Continuous variables were compared using the Wilcoxon rank sum test, and categorical variables were analysed using the Chi-square test or Fisher’s exact test. Multivariable logistic regression analysis results are presented by adjusted odds ratios with 95% confidence intervals and p values.

182 patients underwent 344 non-cardiac procedures with anaesthesia. The median age was 11 years (IQR 5.2–18), 56.4% were male. General anaesthesia was administered in 289 (84%). 125 patients (36.3%) were discharged on the same day. On multivariable analysis, independent predictors that reduced the odds of same-day discharge included the chronic condition index (OR 0.91 per additional chronic condition, 95% CI 0.76–0.98, p = 0.022), undergoing a major surgical procedure (OR 0.17, 95% CI 0.05–0.64, p = 0.009), the use of intraoperative inotropes (OR 0.48, 95% CI 0.25–0.94, p = 0.031), and preoperative admission (OR = 0.24, 95% CI: 0.1–0.57, p = 0.001).

In a contemporary cohort of paediatric and young adults with Fontan physiology, 36.3% were able to be discharged on the same day of their non-cardiac procedure. Well selected patients with Fontan physiology can undergo anaesthesia without complications and be discharged same day.

Systemic-to-pulmonary collateral flow is a well-recognised phenomenon in patients with single ventricle physiology, but remains difficult to quantify. The aim was to compare the reported formula’s that have been used for calculation of systemic-to-pulmonary-collateral flow to assess their consistency and to quantify systemic-to-pulmonary collateral flow in patients with a Glenn and/or Fontan circulation using four-dimensional flow MRI (4D flow MR).

Retrospective case–control study of Glenn and Fontan patients who had a 4D flow MR study. Flows were measured at the ascending aorta, left and right pulmonary arteries, left and right pulmonary veins, and both caval veins. Systemic-to-pulmonary collateral flow was calculated using two formulas: 1) pulmonary veins – pulmonary arteries and 2) ascending aorta – caval veins. Anatomical identification of collaterals was performed using the 4D MR image set.

Fourteen patients (n = 11 Fontan, n = 3 Glenn) were included (age 26 [22–30] years). Systemic-to-pulmonary collateral flow was significantly higher in the patients than the controls (n = 10, age 31.2 [15.1–38.4] years) with both formulas: 0.28 [0.09–0.5] versus 0.04 [−0.66–0.21] l/min/m2 (p = 0.036, formula 1) and 0.67 [0.24–0.88] versus -0.07 [−0.16–0.08] l/min/m2 (p < 0.001, formula 2). In patients, systemic-to-pulmonary collateral flow differed significantly between formulas 1 and 2 (13% versus 26% of aortic flow, p = 0.038). In seven patients, veno-venous collaterals were detected and no aortopulmonary collaterals were visualised.

4D flow MR is able to detect increased systemic-to-pulmonary collateral flow and visualise collaterals vessels in Glenn and Fontan patients. However, the amount of systemic-to-pulmonary collateral flow varies with the formula employed. Therefore, further research is necessary before it could be applied in clinical care.

Pulmonary vasodilator therapy in Fontan patients can improve exercise tolerance. We aimed to assess the potential for non-invasive testing of acute vasodilator response using four-dimensional (D) flow MRI during oxygen inhalation.

Six patients with well-functioning Fontan circulations were prospectively recruited and underwent cardiac MRI. Ventricular anatomical imaging and 4D Flow MRI were acquired at baseline and during inhalation of oxygen. Data were compared with six age-matched healthy volunteers with 4D Flow MRI scans acquired at baseline.

All six patients tolerated the MRI scan well. The dominant ventricle had a left ventricular morphology in all cases. On 4D Flow MRI assessment, two patients (Patients 2 and 6) showed improved cardiac filling with improved preload during oxygen administration, increased mitral inflow, increased maximum E-wave kinetic energy, and decreased systolic peak kinetic energy. Patient 1 showed improved preload only. Patient 5 showed no change, and patient 3 had equivocal results. Patient 4, however, showed a decrease in preload and cardiac filling/function with oxygen.

Using oxygen as a pulmonary vasodilator to assess increased pulmonary venous return as a marker for positive acute vasodilator response would provide pre-treatment assessment in a more physiological state – the awake patient. This proof-of-concept study showed that it is well tolerated and has shown changes in some stable patients with a Fontan circulation.