Redefining Expectations of Long-Term Survival After the Fontan Procedure

Quality of Life and Well-Being in Adults With Fontan Physiology: Findings From the Australian and New Zealand Fontan Registry Quality of Life Study

BACKGROUND

To characterize global and health-related quality of life (QOL) among adults with Fontan physiology enrolled in the Australian and New Zealand Fontan Registry (ANZFR), and identify sociodemographic, clinical, psychological, and relational factors associated with outcomes.

METHODS AND RESULTS

Using a cross-sectional survey design, 66 adults with Fontan physiology (58% women; mean age, 29.6±7.7 years; range, 18-50 years) completed validated self-report measures. Health-related QOL was assessed using the Pediatric Quality of Life Inventory, and global QOL was assessed using a visual analog scale (0-10). Participants reported lower total health-related QOL (P<0.001), as well as lower physical (P<0.001) and social (P=0.002) functioning compared with normative data. Median global QOL was 7.0 (interquartile range: 5.0-8.0) and most participants (71%) rated their QOL ≥6. For health-related QOL, age, sex, university education, and length of hospital stay in the past 12 months explained 27% of the variance in scores, while general psychological stress, medical traumatic stress, communication problems, and access to emotional support explained a further 44% of variance (final model: 71% of variance explained). For global QOL, sociodemographic and clinical factors explained 20% of the variance in scores, while psychological stress and sense of coherence explained a further 24% (final model: 44% of variance explained).

CONCLUSIONS

Adults with Fontan physiology reported lower overall health-related QOL compared with community-based norms. Variance in QOL outcomes were predominantly attributable to psychological and relational factors. Tailored screening and assessment to identify Fontan patients at greatest risk of lower QOL, and a proactive approach to supportive care, are needed.

Successful thromboaspiration of bilateral pulmonary thromboembolism in a Fontan circulation patient: a case report

Background

Fontan surgery aims to palliate univentricular congenital heart diseases in which biventricular repair is not feasible. A large spectrum of early and late complications has been described in literature. However, pulmonary thromboembolism represents a rare complication in these patients, leading to a scarcity of evidence regarding diagnosis and treatment strategies.

Case summary

We present a case of a 27-year-old woman born with a complex cyanotic congenital heart disease, namely pulmonary and tricuspid stenosis with subaortic interventricular communication and atrial septal defect, who underwent palliation surgery with Blalock-Taussig shunt, bidirectional Glenn, and extracardiac Fontan. She developed acute respiratory failure and was admitted to the hospital, being diagnosed with bilateral thromboembolism. Since she was haemodynamically stable, initially, a conservative approach was chosen. However, due to no clinical improvement, she subsequently underwent bilateral thromboaspiration with restoration of pulmonary circulation.

Discussion

Due to the unique Fontan pathophysiology, the possible physiological and clinical implications of pulmonary thromboembolism in this condition are profound. Thus, care and imaging tests in specialized centres are important as the management of these patients is different from those with biventricular physiology.

Impact of the Rudimentary Chamber on Outcomes in Fontan Patients

Background: We sought to evaluate the influence of the rudimentary ventricle on long-term outcomes after the Fontan operation, focusing on exercise capacity and cardiac performance. Methods: Between 1995 and 2021, 290 patients underwent a total cavopulmonary connection. "Two-ventricle" Fontan circulation was defined as a rudimentary ventricle >30% of the dominant ventricle or >50% of its predicted normal value. This cohort was compared with patients with single-ventricle Fontan circulation. The primary endpoint was Fontan failure, and the secondary endpoints were VO2 and cardiac catheterization data at ten years postoperatively. Results: The median follow-up after the Fontan operation was 7.9 years (interquartile range: 1.9-13.9). No significant difference was found in Fontan failure-free survival between the "two-ventricle" Fontan circulation group and the single-ventricle Fontan circulation group (83/91, 93% vs 156/199, 78%), respectively at 20 years; P = .11). No significant difference was found in VO2 or cardiac performance except cardiac index, with 2.9 (2.3-4.8) versus 2.5 (2.3-4.3) L/min/m2 (P = .047). Fifty-one patients in the "two-ventricle" Fontan circulation group were followed up for over ten years after the Fontan operation. In the subgroup analysis of this cohort, the rudimentary ventricular end-diastolic volume/dominant ventricular end-diastolic volume ratio showed a significant positive correlation with dominant ventricular end-diastolic pressure (r = 0.58 [95% CI 0.35-0.74], P = .002) and a significant negative correlation with VO2 (r = -0.61 [95% CI -0.80 to -0.28], P = .001). Conclusions: The rudimentary ventricle was not significantly associated with any clinical disadvantages regarding Fontan failure. However, a large rudimentary ventricle was significantly associated with higher end-diastolic pressure and lower exercise capacity.

Pacemaker-Related Factors and Outcomes of Fontan Patients - Impact of Paced QRS Duration

BACKGROUND

Permanent pacemaker (PPM) implantation has been identified as a risk factor for morbidity and mortality after Fontan operation. This study investigated the factors associated with outcomes in patients with Fontan physiology who underwent PPM implantation.

METHODS AND RESULTS

We retrospectively reviewed 508 patients who underwent Fontan surgery at Asan Medical Center between September 1992 and August 2022. Of these patients, 37 (7.3%) received PPM implantation. Five patients were excluded, leaving 32 patients, of whom 11 were categorized into the poor outcome group. Poor outcomes comprised death, heart transplantation, and "Fontan failure". Clinical, Fontan procedure-related, and PPM-related factors were compared between the poor and good outcome groups. Ventricular morphology, Fontan procedure-associated factors, pacing mode, high ventricular pacing rate, and time from first arrhythmia to PPM implantation did not differ significantly between the 2 groups. However, the poor outcome group exhibited a significantly longer mean paced QRS duration (P=0.044). Receiver operating characteristic curve analysis revealed a paced QRS duration cut-off value of 153 ms with an area under the curve of 0.73 (P=0.035).

CONCLUSIONS

A longer paced QRS duration was associated with poor outcomes, indicating its potential to predict adverse outcomes among Fontan patients.

Cardiovascular remodelling in response to exercise training in patients after the Fontan procedure: a pilot study

BACKGROUND

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.

METHODS AND RESULTS

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.

CONCLUSION

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.

TRIAL REGISTRATION NUMBER

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

Long-Term Renal Involvement in Association with Fontan Circulation

Multiorgan dysfunction is a concern of Fontan patients. To clarify the pathophysiology of Fontan nephropathy, we characterize renal disease in the long-term observational study. Medical records of 128 consecutive Fontan patients [median age: 22 (range 15-37) years old] treated between 2009 and 2018 were reviewed to investigate the incidence of nephropathy and its association with other clinical variables. Thirty-seven patients (29%) showed proteinuria (n = 34) or < 90 mL/min/1.73 m2 of estimated glomerular filtration rate (eGFR) (n = 7), including 4 overlapping cases. Ninety-six patients (75%) had liver dysfunction (Forns index > 4.21). Patients with proteinuria received the Fontan procedure at an older age [78 (26-194) vs. 56 (8-292) months old, p = 0.02] and had a higher cardiac index [3.11 (1.49-6.35) vs. 2.71 (1.40-4.95) L/min/m2, p = 0.02], central venous pressure [12 (7-19) vs. 9 (5-19) mmHg, p < 0.001], and proportion with > 4.21 of Forns index (88% vs. 70%, p = 0.04) than those without proteinuria. The mean renal perfusion pressure was lower in patients with a reduced eGFR than those without it [55 (44-65) vs. 65 (45-102) mmHg, p = 0.03], but no other variables differed significantly. A multivariable analysis revealed that proteinuria was associated with an increased cardiac index (unit odds ratio 2.02, 95% confidence interval 1.12-3.65, p = 0.02). Seven patients with severe proteinuria had a lower oxygen saturation than those with no or mild proteinuria (p = 0.01, 0.03). Proteinuria or a decreased eGFR differentially occurred in approximately 30% of Fontan patients. Suboptimal Fontan circulation may contribute to the development of proteinuria and reduced eGFR.

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.

Tricuspid Valve Repair Can Restore the Prognosis of Patients with Hypoplastic Left Heart Syndrome and Tricuspid Valve Regurgitation: A Meta-analysis

To date, evidence supporting the efficacy of tricuspid valve (TV) repair in interrupting the progression of systemic right ventricular (RV) adverse remodeling in hypoplastic left heart syndrome (HLHS) is conflicting. We conducted a systematic review and meta-analysis of scientific literature to assess the impact of TV repair in effectively modifying the prognosis of patients with HLHS. We conducted a systematic review of PubMed, Web of Science, and Scopus databases. A random-effect meta-analysis was performed and transplant-free survival, freedom from TV regurgitation, and TV reoperation data were reconstructed using the published Kaplan-Meier curves. Nine studies were included, comprising 203 HLHS patients undergoing TV repair and 323 HLHS controls. The estimated transplant-free survival at 1, 5, and 10 years of follow-up was 75.5% [95% confidence interval (CI) = 67.6-84.3%], 63.6% [95% CI = 54.6-73.9%], and 61.9% [95% CI = 52.7-72.6%], respectively. Transplant-free survival was comparable to HLHS peers without TV regurgitation (p = 0.59). Five-year freedom from recurrence of TV regurgitation and freedom from TV reoperation was 57% [95% CI = 46.7-69.7%] and 63.6% [95% CI = 54.5-74.3%], respectively. Younger age and TV repair at the time of Norwood operation increased the risk of TV regurgitation recurrence and the need for TV reoperation. Our meta-analysis supports the efficacy of TV repair in favorably modifying the prognosis of patients with HLHS and TV regurgitation, reestablishing a medium-term transplant-free survival which is comparable to HLHS peers. However, durability of surgery and long-term fate of TV and RV performance are still unclear.

20 years of experience with the Fontan procedure: characteristics and clinical outcomes of children in a tertiary referral hospital

INTRODUCTION

Without participating in a contractile chamber, the Fontan procedure seeks to create a separation of oxygenated and deoxygenated blood in patients with univentricular heart, reducing the risks of long-term hypoxemia and improving their survival. This study describes the clinical outcomes of children undergoing the Fontan procedure between 2000 and 2020 in a tertiary referral hospital care centre in southwestern Colombia.

MATERIALS AND METHODS

A retrospective observational descriptive study. The 81 patients who underwent the Fontan procedure were included. Categorical variables were presented with percentages and continuous variables with measures of central tendency according to the distribution of the data evaluated through the Shapiro-Wilk test. Sociodemographic, clinical, surgical variables, complications, and mortality were described.

RESULTS

Between 2000 and 2020, 81 patients underwent the Fontan procedure: 43 (53.1%) males and a median age of 5.3 years (interquartile range 4.3-6.6). The most common diagnosis was tricuspid atresia (49.4%). The median mean pulmonary arterial pressure was 12 mmHg (interquartile range 10-15), the Nakata index 272 mm2/m2 (interquartile range 204-327), and the McGoon index (interquartile range 1.86-2.3). Seventy-two (88.9%) patients underwent extracardiac Fontan and 44 (54.3%) patients underwent fenestration. The median hospitalisation days were 19 days. The main complication was coagulopathy (19.8%), mortality in the first month between 2000 and 2010 was 8.6%, and after 2010 was 1.2%.

CONCLUSION

The Fontan procedure is a palliative surgery for children with complex heart disease. According to anatomical and physiological variables, the proper choice of patients determines the short- and long-term results.

Preoperative versus postoperative survival in patients with univentricular heart: a nationwide, retrospective study of patients born in 1990-2015

OBJECTIVES

Few data exist on mortality among patients with univentricular heart (UVH) before surgery. Our aim was to explore the results of intention to perform surgery by estimating preoperative vs postoperative survival in different UVH subgroups.

DESIGN

Retrospective.

SETTING

Tertiary centre for congenital cardiology and congenital heart surgery.

PARTICIPANTS

All 595 Norwegian children with UVH born alive from 1990 to 2015, followed until 31 December 2020.

RESULTS

One quarter (151/595; 25.4%) were not operated. Among these, only two survived, and 125/149 (83.9%) died within 1 month. Reasons for not operating were that surgery was not feasible in 31.1%, preoperative complications in 25.2%, general health issues in 23.2% and parental decision in 20.5%. In total, 327/595 (55.0%) died; 283/327 (86.5%) already died during the first 2 years of life. Preoperative survival varied widely among the UVH subgroups, ranging from 40/65 (61.5%) among patients with unbalanced atrioventricular septal defect to 39/42 (92.9%) among patients with double inlet left ventricle. Postoperative survival followed a similar pattern. Postoperative survival among patients with hypoplastic left heart syndrome (HLHS) improved significantly (5-year survival, 42.5% vs 75.3% among patients born in 1990-2002 vs 2003-2015; p<0.0001), but not among non-HLHS patients (65.7% vs 72.6%; p=0.22)-among whom several subgroups had a poor prognosis similar to HLHS. A total of 291/595 patients (48.9%) had Fontan surgery CONCLUSIONS: Surgery was refrained in one quarter of the patients, among whom almost all died shortly after birth. Long-term prognosis was largely determined during the first 2 years. There was a strong concordance between preoperative and postoperative survival. HLHS survival was improved, but non-HLHS survival did not change significantly. This study demonstrates the complications and outcomes encountering newborns with UVH at all major stages of preoperative and operative treatment.

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

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

The application of simultaneous mainstem bronchus dilation with pulmonary artery stenting in the context of hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a congenital diagnosis that necessitates immediate intervention at the beginning of life to ensure survival past infancy and to optimize left-side cardiac function. Often, these required procedures can lead to deleterious side effects and resultant complications. In this case report, we present a 15-month-old patient with HLHS who underwent multiple procedures, including two aortic arch surgeries. After the interventions, the patient experienced left main pulmonary bronchus compression along with pulmonary artery stenosis. In this case, we outline an approach to performing vascular dilation without compromise of airway patency.

TGA + IVS + LVOTO: patterns of practice and outcomes

PURPOSE

Transposition of great arteries with intact ventricular septum and left ventricular outflow tract obstruction (TGA + IVS + LVOTO) is uncommon. We reviewed operations performed in patients with TGA + IVS + LVOTO in the European Congenital Heart Surgeons Association Congenital Database (ECHSA-CD).

METHODS

All 109 patients with a diagnosis of TGA + IVS + LVOTO in ECHSA-CD who underwent cardiac surgery during a 21-year period (01/2000-02/2021, inclusive) were included. Preoperative variables, operative data, and postoperative outcomes were collected.

RESULTS

These 109 patients underwent 176 operations, including 37 (21.0%) arterial switch operations (ASO), 26 (14.2%) modified Blalock-Taussig-Thomas shunts (MBTTS), 11 (6.2%) Rastelli operations, and 13 (7.3%) other palliative operations (8 superior cavopulmonary anastomosis[es], 4 Fontan, and 1 other palliative procedure). Of 37 patients undergoing ASO, 22 had a concomitant procedure.There were 68 (38.6%) reoperations, including 11 pacemaker procedures and 8 conduit operations. After a systemic-to-pulmonary artery shunt, reoperations included shunt reoperation (n = 4), Rastelli (n = 4), and superior cavopulmonary anastomosis (n = 3).Overall Operative Mortality was 8.2% (9 deaths), including three following ASO, two following "Nikaidoh, Kawashima, or LV-PA conduit" procedures, and two following Rastelli. Postoperative complications occurred after 36 operations (20.4%). The most common complications were delayed sternal closure (n = 11), postoperative respiratory insufficiency requiring mechanical ventilation >7 days (n = 9), and renal failure requiring temporary dialysis (n = 8).

CONCLUSION

TGA + IVS + LVOTO is rare (109 patients in ECHSA-CD over 21 years). ASO, MBTTS, and Rastelli are the most common operations performed for TGA + IVS + LVOTO. Larger international studies with long-term follow-up are needed to better define the anatomy of the LVOTO and to determine the optimal surgical strategy.

Liver Cirrhosis After the Fontan Procedure: Impact of Atrioventricular Valve Failure

BACKGROUND

Liver cirrhosis is now well recognized as a potential complication after the Fontan procedure, although associated risk factors and optimal timing of liver screening remain unclear.

METHODS

All patients who underwent an extracardiac conduit Fontan procedure at The Royal Children's Hospital, Melbourne, were identified using the Australia and New Zealand Fontan Registry. Cirrhosis was diagnosed based on liver biopsy, or a combination of imaging findings and clinical evaluation by a hepatologist.

RESULTS

Between 1997 and 2020, 398 patients underwent an extracardiac conduit Fontan procedure at our center, and 276 had ongoing follow-up in Victoria. Ninety-five patients (34%) underwent liver assessment at a mean age of 18.2 ± 6.7 years (11.8 ± 5.5 years post-Fontan). Fifteen patients (16%) were diagnosed with cirrhosis at a mean age of 22.7 ± 5.9 years (14.0 ± 5.2 years post-Fontan). The need for prior or concomitant atrioventricular valve repair or replacement was associated with an increased risk of cirrhosis (univariable hazard ratio [HR] 7.09, 95% confidence interval [CI] 2.13-23.61, P = .001). By multivariable analysis, factors associated with development of cirrhosis were atrioventricular valve failure prior to Fontan (HR 3.27, 95% CI 1.15-9.31, P = .026) and older age at Fontan operation (HR 1.13 per year increase, 95% CI 1.01-1.26, P = .034). The proportion of patients alive, nontransplanted, and without cirrhosis at 10, 15, and 20 years was 93.4% (95% CI 88.4%-98.7%), 79.6% (95% CI 69.7%-90.8%), and 64.6% (95% CI 51.0%-81.9%), respectively.

CONCLUSIONS

Early commencement of liver screening should be considered for patients with a history of atrioventricular failure during Fontan palliation.

Epidemiologic study of patients after Fontan operation based on Medical Aid Program for Chronic Pediatric Diseases of Specified Categories cohort

Nationwide registry data of patients with single-ventricle physiology have been rarely reported. The Medical Aid Program for Chronic Pediatric Diseases of Specified Categories (Japan) has contributed to the financial support of medical expense for patients younger than 20 years with chronic paediatric disease, and almost all children in Japan who require disease-specific treatment voluntarily apply to this programme. The epidemiology and medium- to long-term outcome of patients following a Fontan procedure were investigated using the database. The usefulness of this epidemiologic investigation in identifying real-world objectives and clinical applications was also examined. A total of 2862 patients who underwent a Fontan operation were identified from 18,589 patients with chronic heart disease registered to the medical aid programme. The details of symptoms, treatment, and somatic growth were evaluated, from which we were able to clarify the nationwide data regarding the current status of post-Fontan patients younger than 20 years. This study elucidated the current status of post-Fontan patients under 20 years of age in Japan. Data analysis of the Medical Aid Program for Chronic Pediatric Diseases of Specified Categories cohort provided useful information towards understanding the comprehensive status of patients with chronic heart disease and contributed to improved disease management.

Somatic growth in single ventricle patients: A systematic review and meta-analysis

AIM

To map somatic growth patterns throughout Fontan palliation and summarise evidence on its key modifiers.

METHODS

Databases were searched for relevant articles published from January 2000 to December 2021. Height and weight z scores at each time point (birth, Glenn procedure, Fontan procedure and >5 years after Fontan completion) were pooled using a random effects meta-analysis. A random effects meta-regression model was fitted to model the trend in z scores over time.

RESULTS

Nineteen studies fulfilled eligibility criteria, yielding a total of 2006 participants. The z scores for height and weight were markedly reduced from birth to the interstage period, but recovered by about 50% following the Glenn procedure. At >10 years after the Fontan procedure, the z scores for weight seemed to normalise despite persistent lower height, resulting in increased body mass index. The review revealed a number of modifiers of somatic growth, including aggressive nutritional management, timing of Glenn/Fontan, prompt resolution of complications and obesity prevention programmes in adolescence and adulthood.

CONCLUSION

This review mapped the somatic growth of single ventricle patients and summarised key modifiers that may be amendable to improvement. These data provide guidance on strategies to further optimise somatic growth in this population and may serve as a benchmark for clinical follow-up.

27 years of experience with the Fontan procedure: characteristics and clinical outcomes of children in a tertiary referral hospital

BACKGROUND

The Fontan operation has improved the survival of children born with congenital heart disease with single ventricle physiology. The most widely adopted variations of the Fontan procedure are the extracardiac conduit, the lateral tunnel ve the intra/extracardiac conduit with fenestration. Despite advances in the treatment and prevention of early and late complications that may develop after Fontan surgery, morbidity still remains an important problem.

METHODS

304 patients who underwent Fontan surgery in our center between 1995 and 2022 were included in our study. The complications that developed in patients who underwent primary Fontan or lateral tunnel surgery and extracardiac conduit Fontan application were compared.

RESULTS

Classic Fontan surgery and lateral tunnel surgery were performed in 26 of the patients, and extracardiac Fontan surgery was performed in 278 patients. 218 of 304 cases were patients with single ventricular pathology. 86 cases were patients with two ventricular morphologies but complex cardiac pathology. Fenestration was performed in only 6 patients, other patients did not require fenestration. The mean follow-up period of our patients was 12 years (3 months-27 years). When the complications between Fontan procedures were compared in our study, it was found that the length of hospital stay and mortality were statistically significantly reduced in patients who underwent extracardiac Fontan surgery. There was no significant difference in terms of complications that can be seen after Fontan surgery and the length of stay in the intensive care unit.

CONCLUSION

Fontan complex is a palliative surgery for children with complex heart disease. Palliative surgical operations aimed at the preparation of the Fontan circulation lead to the preparation of the pulmonary vascular bed and the preservation of ventricular function. The techniques applied in Fontan surgery affect the early and long-term complications and the survival of the patients. In our study, when we examined the patients who extracardiac conduit Fontan procedure for the non-cardiac route, we found that mortality and morbidity were minimal.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Extracorporeal membrane oxygenation in curing a young man after modified Fontan operation: A case report

BACKGROUND

The Fontan operation is the only treatment option to change the anatomy of the heart and help improve patients’ hemodynamics. After successful operation, patients typically recover the ability to engage in general physical activity. As a better ventilatory strategy, extracorporeal membrane oxygenation (ECMO) provides gas exchange via an extracorporeal circuit, and is increasingly being used to improve respiratory and circulatory function. After the modified Fontan operation, circulation is different from that of patients who are not subjected to the procedure. This paper describe a successful case using ECMO in curing influenza A infection in a young man, who was diagnosed with Tausing-Bing syndrome and underwent Fontan operation 13 years ago. The special cardiac structure and circulatory characteristics are explored in this case.

CASE SUMMARY

We report a successful case using ECMO in curing influenza A infection in a 23-year-old man, who was diagnosed with Tausing-Bing syndrome and underwent Fontan operation 13 years ago. The man was admitted to the intensive care unit with severe acute respiratory distress syndrome as a result of influenza A infection. He was initially treated by veno-venous (VV) ECMO, which was switched to veno-venous-arterial ECMO (VVA ECMO) 5 d later. As circulation and respiratory function gradually improved, the VVA ECMO equipment was removed on May 1, 2018. The patient was successfully withdrawn from artificial ventilation on May 28, 2018 and then discharged from hospital on May 30, 2018.

CONCLUSION

After the modified Fontan operation, circulation is different compared with that of patients who are not subjected to the procedure. There are certainly many differences between them when they receive the treatment of ECMO. Due to the special cardiac structure and circulatory characteristics, an individualized liquid management strategy is necessary and it might be better for them to choose an active circulation support earlier.

Impact of older age at Fontan completion on mid-term survival

BACKGROUND

The optimum age of Fontan completion remains unknown. Currently, the majority of centers worldwide are performing Fontan completion at 2-4 years of age. In Indonesia, lack of awareness and limited resources probably explain why patients seek treatment at advanced stage. This study aimed to evaluate the impact of older age at Fontan completion on mid-term survival.

RESULTS

A single-center retrospective cohort study was performed on 261 patients who underwent Fontan completion between 2008 and 2019 and survived to discharge. The patients were followed up until April 2020, with a median follow-up period of 3 years (range 0-12 years). The median age was 5 years (range 2-24 years). The survival rates of patients with the age at operation ≤ 6 years and > 6 years were 92.1% and 82.8%, respectively. A subgroup analysis showed that the survival rates for age < 4 years, 4-6 years (reference age), 6-8 years, 8-10 years, 10-18 years, and > 18 years were 85.7%, 94.8%, 85.4%, 78.8%, 85.7%, and 66.7%, respectively. Age at Fontan completion of > 6 years (HR 3.84; p = 0.020) was associated with a lower 12-year survival rate. The age at operation of 8-10 years (HR 6.79; p = 0.022) and > 18 years (HR 15.30; p = 0.006) had the worst survival rates.

CONCLUSIONS

An older age at Fontan completion (> 6 years) significantly reduced mid-term survival rate. The age at Fontan of 8-10 years and > 18 years had higher risk of mid-term death than age of 4-6 years.

Body Mass Index Trajectory and Outcome Post Fontan Procedure

Background Patients with a single ventricle who experience early life growth failure suffer high morbidity and mortality in the perisurgical period. However, long-term implications of poor infant growth, as well as associations between body mass index (BMI) and outcome in adulthood, remain unclear. We aimed to model BMI trajectories of patients with a single ventricle undergoing a Fontan procedure to determine trajectory-based differences in baseline characteristics and long-term clinical outcomes. Methods and Results We performed a retrospective analysis of medical records from patients in the Australia and New Zealand Fontan Registry receiving treatment at the Royal Children's Hospital, The Children's Hospital at Westmead, Royal Melbourne Hospital, and Royal Prince Alfred Hospital from 1981 to 2018. BMI trajectories were modeled in 496 patients using latent class growth analysis from 0 to 6 months, 6 to 60 months, and 5 to 16 years. Trajectories were compared regarding long-term incidence of severe Fontan failure (defined as mortality, heart transplantation, Fontan takedown, or New York Heart Association class III/IV heart failure). Three trajectories were found for male and female subjects at each age group-lower, middle, higher. Subjects in the lower trajectory at 0 to 6 months were more likely to have an atriopulmonary Fontan and experienced increased mortality long term. No association was found between higher BMI trajectory, current BMI, and long-term outcome. Conclusions Poor growth in early life correlates with increased long-term severe Fontan failure. Delineation of distinct BMI trajectories can be used in larger and older cohorts to find optimal BMI targets for patient outcome.

The Ventricular Switch: An Alternative Strategy Toward Biventricular Repair in Moderately Hypoplastic Left Ventricles or Complex Connections

Hypoplastic left heart complex (HLHC) constitutes a spectrum of left ventricular hypoplasia and valvar disease and can be associated with increased morbidity and mortality. Traditionally, management of these lesions involves single ventricle palliation (SVP). However, the SVP may be associated with substantial long-term consequences related to its physiology. Alternative management strategies have been employed to achieve biventricular circulation. We have proposed a novel technique, termed the "ventricular switch" procedure, in which the hypoplastic or unroutable left ventricle can be harnessed to function as the subpulmonic ventricle, and the right ventricle functions as the systemic ventricle. Herein, we describe our rationale for considering biventricular circulation and the ventricular switch procedure in HLHC and in other complex lesions.

A diffusion MRI study of brain white matter microstructure in adolescents and adults with a Fontan circulation: Investigating associations with resting and peak exercise oxygen saturations and cognition

INTRODUCTION

Adolescents and adults with a Fontan circulation are at risk of cognitive dysfunction; Attention and processing speed are notable areas of concern. Underlying mechanisms and brain alterations associated with worse long-term cognitive outcomes are not well determined. This study investigated brain white matter microstructure in adolescents and adults with a Fontan circulation and associations with resting and peak exercise oxygen saturations (SaO₂), predicted maximal oxygen uptake during exercise (% pred VO₂), and attention and processing speed.

METHODS

Ninety-two participants with a Fontan circulation (aged 13-49 years, ≥5 years post-Fontan completion) had diffusion MRI. Averaged tract-wise diffusion tensor imaging (DTI) metrics were generated for 34 white matter tracts of interest. Resting and peak exercise SaO₂ and % pred VO₂ were measured during cardiopulmonary exercise testing (CPET; N = 81). Attention and processing speed were assessed using Cogstate (N = 67 and 70, respectively). Linear regression analyses adjusted for age, sex, and intracranial volume were performed to investigate associations between i) tract-specific DTI metrics and CPET variables, and ii) tract-specific DTI metrics and attention and processing speed z-scores.

RESULTS

Forty-nine participants were male (53%), mean age was 23.1 years (standard deviation (SD) = 7.8 years). Mean resting and peak exercise SaO₂ were 93.1% (SD = 3.6) and 90.1% (SD = 4.7), respectively. Mean attention and processing speed z-scores were -0.63 (SD = 1.07) and -0.72 (SD = 1.44), respectively. Resting SaO₂ were positively associated with mean fractional anisotropy (FA) of the left corticospinal tract (CST) and right superior longitudinal fasciculus I (SLF-I) and negatively associated with mean diffusivity (MD) and radial diffusivity (RD) of the right SLF-I (p ≤ 0.01). Peak exercise SaO₂ were positively associated with mean FA of the left CST and were negatively associated with mean RD of the left CST, MD of the left frontopontine tract, MD, RD and axial diffusivity (AD) of the right SLF-I, RD of the left SLF-II, MD, RD and AD of the right SLF-II, and MD and RD of the right SLF-III (p ≤ 0.01). Percent predicted VO₂ was positively associated with FA of the left uncinate fasciculus (p < 0.01). Negative associations were identified between mean FA of the right arcuate fasciculus, right SLF-II and right SLF-III and processing speed (p ≤ 0.01). No significant associations were identified between DTI-based metrics and attention.

CONCLUSION

Chronic hypoxemia may have long-term detrimental impact on white matter microstructure in people living with a Fontan circulation. Paradoxical associations between processing speed and tract-specific DTI metrics could be suggestive of compensatory white matter remodeling. Longitudinal investigations focused on the mechanisms and trajectory of altered white matter microstructure and associated cognitive dysfunction in people with a Fontan circulation are required to better understand causal associations.

Transcatheter Thoracic Duct Decompression for Multicompartment Lymphatic Failure After Fontan Palliation

BACKGROUND

Lymphatic embolization therapy has proven effective for Fontan failure from plastic bronchitis or protein-losing enteropathy but not when multiple lymphatic compartments are involved; furthermore, embolization does not alter the underlying pathophysiology of lymphatic dysfunction. A technique for transcatheter thoracic duct decompression (TDD), rerouting the thoracic duct to the pulmonary venous atrium to treat multicompartment lymphatic failure is described and early outcomes presented.

METHODS

Initially covered stents were used to channel the innominate vein flow inside of the cavopulmonary pathway into the pulmonary venous atrium. A modified approach was developed where covered stents redirected innominate vein directly to the left atrium via an extravascular course. Baseline and follow-up data on all patients undergoing TDD were reviewed.

RESULTS

Twelve patients underwent TDD between March 2018 and February 2021 at a median age of 12 (range: 2-22) years. Lymphatic failure occurred in median of 3 compartments per patient (protein-losing enteropathy, ascites, pleural effusions, plastic bronchitis); 10 patients had lymphatic embolizations before TDD. TDD method was intra-Fontan tunnel in 4, direct approach in 7, and other in 1. There were no major procedural complications; 6 patients underwent subsequent procedures, most commonly to treat endoleaks. Lymphatic failure resolved in 6 patients, improved in 2, and was unchanged in 4 at 6 (range: 1-20) months follow-up. One patient died after TDD from Fontan failure.

CONCLUSIONS

TDD is a promising new treatment for the failing Fontan physiology from multicompartment lymphatic failure. Additional work is needed to refine the technique and define optimal candidates.

Impact of Fontan Fenestration on Long-Term Outcomes: A Propensity Score-Matched Analysis

Background The long-term impact of fenestration at the time of Fontan operation remains unclear. We aimed to review the early and long-term impact of Fontan fenestration in the Australia and New Zealand cohort. Methods and Results We reviewed 1443 patients (621 fenestrated, 822 nonfenestrated) from the Australia and New Zealand Fontan registry. Data were collected on preoperative demographics, operative details, and follow-up. Propensity-score matching was performed to account for the various preoperative and operative differences and risk factors. Primary outcomes were survival and freedom from failure. Median follow-up was 10.6 years. After propensity-score matching (407 matched pairs), there was no difference in survival (87% versus 90% at 20 years; P=0.16) or freedom from failure (73% versus 80% at 20 years; P=0.10) between patients with and without fenestration, respectively. Although patients with fenestration had longer bypass and cross-clamp times (P<0.001), there was no difference in hospital length of stay or prolonged pleural effusions (P=0.80 and P=0.46, respectively). Freedom from systemic and Fontan circuit thromboembolism was higher in the nonfenestrated group (89%; 95% CI, 88%-95%) than the fenestrated group (84%; 95% CI, 77%-89%; P=0.03). There was no difference in incidence of plastic bronchitis, protein-losing enteropathy, New York Heart Association Class III/IV symptoms, or Fontan takedown. Conclusions In the propensity score-matched analysis we have demonstrated no difference in long-term survival or freedom from Fontan failure in patients with and without fenestration. There was a higher incidence of long-term thromboembolic events in patients with fenestration. Overall, it appears that fenestration in Fontan circulation does not bring long-term benefits.

Hypoplastic Left Heart Syndrome Across the Lifespan: Clinical Considerations for Care of the Fetus, Child, and Adult

Hypoplastic left heart syndrome (HLHS) is the most common anatomic lesion in children born with single ventricle physiology and is characterized by the presence of a dominant right ventricle and a hypoplastic left ventricle along with small left-sided heart structures. Diagnostic subgroups of HLHS reflect the extent of inflow and outflow obstruction at the aortic and mitral valves, specifically stenosis or atresia. If left unpalliated, HLHS is a uniformly fatal lesion in infancy. Following introduction of the Norwood operation, early survival has steadily improved over the past four decades, mirroring advances in operative and peri-operative management as well as reflecting refinements in patient surveillance and interstage clinical care. Notably, survival following staged palliation has increased from 0% to a 5-year survival of 60-65% for children in some centres. Despite the prevalence of HLHS in childhood with relatively favourable surgical outcomes in contemporary series, this cohort is only now reaching early adult life and longer-term outcomes have yet to be elucidated. In this article we focus on contemporary clinical management strategies for patients with HLHS across the lifespan, from fetal to adult life. Nomenclature and diagnostic considerations are discussed and current literature pertaining to putative genetic etiologies is reviewed. The spectrum of fetal and pediatric interventional strategies, both percutaneous and surgical, are described. Clinical, patient-reported and neurodevelopmental outcomes of HLHS are delineated. Finally, note is made of current areas of clinical uncertainty and suggested directions for future research are highlighted.

Late outcome of Extracardiac Fontan Patients: 32 years of follow-up

OBJECTIVES

We sought to evaluate the long-term survival and risk factors for morbidity and mortality in our cohort of patients after Extracardiac (EC) Fontan.

METHODS

We collected and analyzed follow-up data until September 2020 for all patients who underwent EC Fontan operation at our institution from November 1988 to November 2015.

RESULTS

Out of 406 patients treated with EC Fontan at a mean age of 5.4 ± 4.5 years, 372 (91.6%) were discharged home; 15% were lost to follow-up. The Median follow-up was 14.6 years (IQR 8.7-20.3). Two hundred patients (54%) had a good long-term outcome, with an event-free long-term survival, but late adverse events of any kind needing interventional or surgical reoperations were reported in 128 patients (34%). Forty-four patients (12%) developed late Fontan failure. Thirty-seven survivors (10%) had late arrhythmias, with the need for pacemaker implantation. Obstruction of the cavopulmonary pathway occurred in forty-nine patients (13%), but just 8 pts needed conduit surgical replacement. At 32 years, the survival probability was 84%. The risk of orthotopic heart transplant (HT), considering death as a competing event, (showed as cumulative incidence) was 12.5%. A preoperative diagnosis of hypoplastic left heart syndrome (HLHS) was an independent risk factor for the need for HT.

CONCLUSIONS

The EC Fontan shows satisfactory long-term survival and low incidence of adverse events and late failure. Conduit replacement is rare, and its longevity may not represent a substantial issue in these patients. However, as with other technical variants, the need for reoperations during long-term follow-up is a significant challenge.

Cardiopulmonary Exercise Test Outcomes in Fontan Patients With Right Versus Left Single Ventricle Morphology

Background: Congenital heart defects (CHDs) palliated with Fontan surgery often result in a functional single ventricle that is either a morphologically right or left ventricle, and much less commonly undefined. Given this departure from normal physiology, especially for systemic right ventricle Fontan patients, our study sought to compare cardiopulmonary exercise test (CPET) results of adult patients with single right ventricle (SRV) and single left ventricle (SLV) morphology. Methods: Of 237 Fontan patients from the Ahmanson/UCLA Adult Congenital Heart Disease Center database, 135 patients met the inclusion criteria and were split into 2 groups: SRV (n = 44) and SLV (n = 91). Data were collected on baseline demographics, cardiac history, and CPET results. The 2 groups were compared using unpaired t-test, Mann-Whitney, or Chi-square test. Results: Regarding baseline demographics, SRV patients underwent CPET at a slightly younger age than the SLV group (26.5 ± 6.2 vs 29.6 ± 8.5 years, P = .03). There were no significant differences in CPET parameters (including peak heart rate, oxygen saturation, and maximum VO₂/kg) between the SRV and SLV groups. When evaluated subsequent CPET at 3 to 4 years, there was no difference in CPET peak heart rate, peak oxygen saturation, and maximum VO₂/kg between the 2 groups. Conclusions: This single-center retrospective analysis suggests that dominant single ventricle morphology may not be associated with an appreciable difference in exercise performance in adult survivors with a Fontan palliation.

Dominant Ventricular Morphology and Early Postoperative Course After the Fontan Procedure

Background

Single ventricle heart disease comprises a wide variety of critical heart defects that lead to the provision of systemic cardiac output by one dominant ventricle. It requires staged surgical palliation that culminates in Fontan circulation. Dominant ventricular morphology in single ventricle patients reportedly has an impact on postoperative morbidity and mortality with varying results. The objectives of this study were to examine the association between ventricular morphology and the early postoperative course after the Fontan procedure.

Methods

A retrospective cohort study in a tertiary referral pediatric medical center that included 98 consecutive patients who underwent Fontan procedure between October 2009 and May 2016. Postoperative outcomes were compared between patients with left ventricular morphology and those with right ventricular morphology (crude effect and regression analysis).

Results

Patients with right ventricular morphology had longer postoperative hospitalizations compared to patients with left ventricular morphology (26.5 days vs 18.2 days, respectively, P = .028), higher postoperative maximal vasoactive-inotropic scores (25.6 vs 12.4, P = .02), higher serum lactate levels (7.7 mmol/L vs 6.4 mmol/L, P = .03), higher proportions of ventilation throughout 24 h or more (16 patients [38%] vs 8 patients [14%], P = .009), higher proportions of ventricular dysfunction (12 patients [29%] vs 5 patients [9%], P = .0001), and lower blood oxygen saturation levels at discharge (87% vs 92%, P = .03).

Conclusions

The Fontan procedure in patients with right ventricular morphology is associated with longer postoperative hospitalization and worse early postoperative characteristics (ventricular dysfunction and atrioventricular valve regurgitation) as well as higher rates of early, transient signs of sub-optimal postoperative hemodynamics compared to those with left ventricular morphology.

Considerations in Critical Care and Anesthetic Management of Adult Patients Living with Fontan Circulation

The Fontan procedure is a staged palliation for various complex congenital cardiac lesions, including tricuspid atresia (TA), pulmonary atresia (PA), hypoplastic left heart syndrome (HLHS), and double inlet left ventricle (DILV), all of which involve a functional single-ventricle physiology. The complexity of the patients' original anatomy combined with the anatomical and physiological consequences of the Fontan circulation creates challenges. Teens and adults living with Fontan palliation will need perioperative support for non-cardiac surgery, peripartum management for labor and delivery, interventions related to their structural heart disease, electrophysiology procedures, pacemakers, cardioversions, cardiac surgery, transplant, and advanced mechanical support. This review focuses on the anesthetic and ICU management of these patients during their perioperative journey, with an emphasis on the continuity of pre-intervention planning, referral pathways, and post-intervention intensive care unit (ICU) management. Requests for recipes and doses of medications are frequent; however, as in normal anesthesia and ICU practice, the method of anesthesia and dosing are dependent on the presenting medical/surgical conditions and the underlying anatomy and physiological reserve. A patient with Fontan palliation in their early 20s attending school full-time with a cavopulmonary connection is likely to have more reserve than a patient in their late 40s with an atrio- pulmonary (AP) Fontan at home waiting for a heart transplant. Each case will require an anesthetic and critical care plan tailored to their situation. The critical care environment is a natural extension of the anesthetic management of a patient, with complex considerations for a patient with Fontan palliation.

Novel Protein-Protein Interactions Highlighting the Crosstalk between Hypoplastic Left Heart Syndrome, Ciliopathies and Neurodevelopmental Delays

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) affecting 1 in 5000 newborns. We constructed the interactome of 74 HLHS-associated genes identified from a large-scale mouse mutagenesis screen, augmenting it with 408 novel protein-protein interactions (PPIs) using our High-Precision Protein-Protein Interaction Prediction (HiPPIP) model. The interactome is available on a webserver with advanced search capabilities. A total of 364 genes including 73 novel interactors were differentially regulated in tissue/iPSC-derived cardiomyocytes of HLHS patients. Novel PPIs facilitated the identification of TOR signaling and endoplasmic reticulum stress modules. We found that 60.5% of the interactome consisted of housekeeping genes that may harbor large-effect mutations and drive HLHS etiology but show limited transmission. Network proximity of diabetes, Alzheimer's disease, and liver carcinoma-associated genes to HLHS genes suggested a mechanistic basis for their comorbidity with HLHS. Interactome genes showed tissue-specificity for sites of extracardiac anomalies (placenta, liver and brain). The HLHS interactome shared significant overlaps with the interactomes of ciliopathy- and microcephaly-associated genes, with the shared genes enriched for genes involved in intellectual disability and/or developmental delay, and neuronal death pathways, respectively. This supported the increased burden of ciliopathy variants and prevalence of neurological abnormalities observed among HLHS patients with developmental delay and microcephaly, respectively.

Being Born with a Single Cardiac Ventricle: What Do We Tell Prospective Parents

Being born with a single ventricle remains one of the most extreme congenital cardiac conditions. It encompasses a wide variety of lesions characterized by the existence of one small ventricular cavity. To allow survival, these patients must undergo a series of operations in the first years of life. It was long considered that the success of these interventions would be short-lived and that only a few of these patients would live beyond adulthood. The last decade has seen publication of multiple large outcomes researches on this population, and we now realize that its survival is longer than expected, but with a considerable burden of disease. As a consequence, the size of this single ventricle population is growing rapidly. As primary conveyer of the information on the future of these babies, obstetricians need to be aware of these changes in perspective. This article is protected by copyright. All rights reserved.

A Multimodal Score Accurately Classifies Fontan Failure and Late Mortality in Adult Fontan Patients

Objectives

Despite the outstanding success of the Fontan operation, it is a palliative procedure and a substantial number of patients experience late failure of the Fontan circulation. Clinical presentation and hemodynamic phenotypes of Fontan failure are considerably variable. While various parameters have been identified as risk factors for late Fontan failure, a feasible score to classify Fontan failure and possibly allow timely risk stratification is lacking. Here, we explored the possibility of developing a score based on hemodynamic, clinical and laboratory parameters to classify Fontan failure and mortality.

Methods

We performed a retrospective study in our cohort of adult Fontan patients from two institutions [n = 198, median follow-up after Fontan 20.3 (IQR 15.6–24.3) years], identifying those patients with clinical Fontan failure (n = 52, 26.3%). Various hemodynamic, echocardiographic, laboratory and clinical data were recorded and differences between patients with and without Fontan failure were analyzed. We composed a Fontan Failure Score containing 15 parameters associated with Fontan failure and/or mortality and assessed its accuracy to discriminate between patients with and without late Fontan failure as well as late mortality and survival.

Results

Late failure occurred at a median of 18.2 (IQR 9.1–21.1) years after Fontan completion. Mortality associated with Fontan failure was substantial (25/52, 48.1%) with freedom of death/transplantation/take-down of 64% at 5 years and 36% at 10 years after onset of Fontan failure, respectively. Patients with Fontan failure had a significantly higher median Fontan Failure Score compared to non-failing Fontan patients [8 points (IQR 5–10) vs. 2 points (IQR 1-5), p < 0.001]. The score accurately classifies Fontan failure as well as mortality as assessed with receiver operating characteristic analysis. Area under the curve of the Fontan Failure Score was 0.963 (95% CI 0.921; 0.985, p < 0.001) to discriminate failure and 0.916 (95% CI 0.873; 0.959, p < 0.001) to classify mortality.

Conclusion

We have developed an uncomplex yet remarkably accurate score to classify Fontan failure and late mortality in adult Fontan patients. Prospective validation and most likely refinement and calibration of the score in larger and preferably multi-institutional cohorts is required to assess its potential to predict the risk of Fontan failure and late mortality.

Home-Based Long-Term Physical Endurance and Inspiratory Muscle Training for Children and Adults With Fontan Circulation—Initial Results From a Prospective Study

Background

Patients with congenital heart disease (CHD)—including those after Fontan operation—are encouraged to be physically active.

Aim

To prospectively determine the effects of an individually adapted, home-based cycle ergometer endurance training in combination with inspiratory muscle training (IMT) in pediatric and adult Fontan patients. We, herein, report the results of the initial 10-months follow-up (phase 1).

Methods

18 patients (median age 16.5 years; range 10-43 years) completed baseline check-ups, and 4 and 10 months follow-up visits, which each included cardiopulmonary exercise testing (CPET), bodyplethysmography (including measurement of respiratory muscle strength), and a quality of life questionnaire (PedsQL™). The training program consisted of a home-based cycle ergometer endurance training on a “Magbike® AM-5i/3i” (DKN Technology®, Clermont-Ferrand, France) and IMT with a handheld “POWERbreathe® Medic plus” device. Patients performed 90 min of endurance training per week in addition to IMT (30 breaths per day, 6-7 times per week). After the first 4 months, patients underwent additional interval training.

Results

After 10 months of training, we observed significant increases in maximum relative workload (W/kg, p = 0.003) and in maximum inspiratory (MIP, p = 0.002) and expiratory (MEP, p = 0.008) pressures. Peak VO2 values did not increase significantly as compared to baseline (p = 0.12) in the entire cohort (n = 18), but reached statistical significance in a subgroup analysis of teenage/adult patients (n = 14; p = 0.03). Patients' subjective quality of life did not show any significant changes after 10 months of training.

Discussion

In Fontan patients, an individually adapted home-based training is safe and associated with improvements in some CPET variables. However, these improvements did not translate into an improved QoL after 10 months. With an unclear, but most likely negative, impact of the COVID-19 pandemic, improvements in QoL may become evident during further follow-up (phase 2 of the study).

Ventricular assist device for Fontan: who, when and why?

PURPOSE OF REVIEW

Since the advent of the Fontan palliation, survival of patients with univentricular congenital heart disease has increased significantly. These patients will, however, ultimately develop heart failure requiring advanced therapies such as heart transplantation. As wait times are long, mechanical circulatory support (MCS) is an attractive therapy, both for bridge to transplantation and destination therapy in patients not suitable for transplantation. This review aims to summarize current thinking about how to determine which patients would benefit from a ventricular assist device (VAD), the optimal time for implantation and which device should be considered.

RECENT FINDINGS

VAD implantation in end-stage Fontan is still in its infancy; however, case reports and research interest have increased extensively in the past few years. Mortality is significantly higher than in noncongenital heart disease patients. Implantation in patients with primarily systolic dysfunction is indicated, whereas patients with increased transpulmonary gradient may not benefit from a single-VAD solution. When possible, implantation should occur prior to clinical decompensation with evidence of end-organ damage, as outcomes at this point are worse.

SUMMARY

Fontan patients demonstrating signs of heart failure should be evaluated early and often for feasibility and optimal timing of VAD implantation. The frequency of this procedure will likely increase significantly in the future.

Hemodynamic Characteristics After Fontan Procedure in Patients with Down's Syndrome

Patients with Down's syndrome (DS) are generally regarded as not being good candidates for the Fontan procedure. However, detailed hemodynamic changes over time are not fully clarified. A retrospective chart review of all patients with DS who underwent the Fontan procedure and 5 times that number of Fontan patients without DS performed in Fukuoka Children's Hospital and Kyushu University Hospital. Seven Fontan patients with DS were identified, and 35 Fontan patients without DS were recruited. During the mean observational periods of 14.7 years and 15.0 years (DS and non-DS, respectively) after the Fontan procedure, only one DS patient died. Central venous pressure (CVP) and transpulmonary pressure gradient significantly increased, and arterial oxygen saturation significantly decreased over time in DS patients after the Fontan procedure compared with those without DS. CVP in DS patients after the Fontan procedure increased over time compared with non-DS patients. Better management including the efficacy of Pulmonary arterial hypertension-specific therapy should be clarified in further studies.

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.

Morphologic Alterations Precede Functional Hepatic Impairment as Determined by 13C-Methacetin Liver Function Breath Test in Adult Fontan Patients

Objectives: Fontan-associated liver disease (FALD) is the most common end-organ dysfunction affecting up to 70–80% of the Fontan population. The clinical significance of FALD is incompletely understood and no unambiguous correlation between hepatic function and FALD severity has been established. In this study, we sought to evaluate maximal liver function capacity with liver maximum function capacity test (LiMAx®) in adult Fontan patients.

Methods: Thirty-nine adult Fontan patients (median age: 29.4 years [IQR 23.4; 37.4], median follow-up after Fontan operation: 23.9 years [IQR 17.8;26.4]) were analyzed in a cross-sectional observational study using LiMAx® test (Humedics GmbH, Berlin, Germany), laboratory testing, transient elastography (TE) and hepatic ultrasound. The LiMAx® test is based on the metabolism of ¹³C-methacetin, which is administered intravenously and cleaved by the hepatic cytochrome P4501A2 to paracetamol and ¹³CO₂, which is measured in exhaled air and correlates with maximal liver function capacity.

Results: Maximal liver function capacity assessed by LiMAx® test was normal in 28 patients (>315 μg/h^*kg) and mildly to moderately impaired in 11 patients (140–314 μg/h^*kg), while no patient displayed severe hepatic impairment (<139 μg/kg^*h). No correlation was found between maximal liver function capacity and hepatic stiffness by TE (r² = −0.151; p = 0.388) or the presence of sonographic abnormalities associated with FALD (r² = −0.204, p = 0.24). There was, however, an association between maximal liver function capacity and the laboratory parameters bilirubin (r² = −0.333, p = 0.009) and γ-glutamyl transferase (r² = −0.367; p = 0.021). No correlation was detected between maximal liver function capacity and the severity of FALD (r² = −0.235; p = 0.152).

Conclusion: To the best of our knowledge, this is the first study to evaluate maximal liver function capacity using LiMAx® test in Fontan patients, which is a useful complementary diagnostic instrument to assess chronic hepatic injury. Maximal liver function capacity was preserved in most of our adult Fontan patients despite morphologic evidence of FALD. Moreover, maximal liver function capacity does not correlate with the extent of FALD severity evaluated by sonography or laboratory analysis. Thus, the development and progression of FALD in Fontan patients is not a uniform process and diagnostics of chronic hepatic injury during follow-up should encompass various modalities.

Fontan circulation has improved life expectancy for infants born with complex heart disease over the last 50 years but has also resulted in significant morbidity

The prognosis for infants born with complex heart disease improved dramatically with the introduction of the Fontan circulation 50 years ago. With today's carefully designed and staged operations to a Fontan circulation, life expectancy has increased and most children will survive into adult life. The Fontan circulation entails an unphysiological circulation with high risk for multiple organ system dysfunction. Neurodevelopmental disabilities with adverse psychosocial effects are prevalent. The Fontan circulation may eventually fail and necessitate heart transplantation. CONCLUSION: Fifty years development of the Fontan circulation to today's staged surgical procedures has improved survival but also revealed the burden of a high morbidity for a growing number of patients.

Increased Risk for Thromboembolism After Fontan Surgery: Considerations for Thromboprophylaxis

The Fontan circulation introduces an increased risk of thromboembolism which is associated with substantial mortality and morbidity. Adverse outcomes of thromboembolic complications post-Fontan surgery vary in both nature and severity, ranging from local tissue infarction and pulmonary embolism to Fontan failure and ischemic stroke. Furthermore, recent studies have identified that subclinical stroke is common yet underdiagnosed in Fontan patients. Fontan patients are commonly treated with antiplatelet agents and/or anticoagulants as primary thromboprophylaxis. Optimal thromboprophylaxis management in the Fontan population is still unclear, and clinical consensus remains elusive despite the growing literature on the subject. This perspective will describe the nature of thromboembolism post-Fontan surgery and provide evidence for the use of both current and emerging thromboprophylaxis options for children and adults living with Fontan circulation.

Management of circulatory failure after Fontan surgery

With improvement in survival after Fontan surgery resulting in an increasing number of older survivors, there are more patients with a Fontan circulation experiencing circulatory failure each year. Fontan circulatory failure may have a number of underlying etiologies. Once Fontan failure manifests, prognosis is poor, with patient freedom from death or transplant at 10 years of only about 40%. Medical treatments used include traditional heart failure medications such as renin-angiotensin-aldosterone system blockers and beta-blockers, diuretics for symptomatic management, antiarrhythmics for rhythm control, and phosphodiesterase-5 inhibitors to decrease PVR and improve preload. These oral medical therapies are typically not very effective and have little data demonstrating benefit; if there are no surgical or catheter-based interventions to improve the Fontan circulation, patients with severe symptoms often require inotropic medications or mechanical circulatory support. Mechanical circulatory support benefits patients with ventricular dysfunction but may not be as useful in patients with other forms of Fontan failure. Transplant remains the definitive treatment for circulatory failure after Fontan, but patients with a Fontan circulation face many challenges both before and after transplant. There remains significant room and urgent need for improvement in the management and outcomes of patients with circulatory failure after Fontan surgery.

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.

Impairments in Pulmonary Function in Fontan Patients: Their Causes and Consequences

Patients with a Fontan circulation lack a sub-pulmonary ventricle with pulmonary blood flow passively redirected to the lungs. In the Fontan circulation, ventilation has a significant influence on pulmonary blood flow and cardiac output both at rest and with exercise. Children and adults with a Fontan circulation have abnormalities in lung function. In particular, restrictive ventilatory patterns, as measured by spirometry, and impaired gas transfer, as measured by the diffusing capacity of carbon monoxide, have been frequently observed. These abnormalities in lung function are associated with reduced exercise capacity and quality of life. Moderate to severe impairment in lung volumes is independently associated with reduced survival in adults with congenital heart disease. Skeletal and inspiratory muscle weakness has also been reported in patients with a Fontan circulation, with the prospect of improving respiratory muscle function through exercise training programs. In this review, we will present data on cardiopulmonary interactions in the Fontan circulation, the prevalence and severity of impaired lung function, and respiratory muscle function in this population. We will discuss potential causes for and consequence of respiratory impairments, and their impact on exercise capacity and longer-term Fontan outcome. We aim to shed light on possible strategies to reduce morbidity by improving respiratory function in this growing population of patients.