Mode of death and predictors of mortality in adult Fontan survivors: A Japanese multicenter observational study

Are Arrhythmias Adequately Incorporated into Studies on Long-Term Outcomes After the Fontan Operation?

Arrhythmias are common after the Fontan operation and increase risk of morbidity and mortality. Their impact on late outcomes remains poorly understood. Our objective was to assess whether long-term studies after the Fontan incorporated the impact of arrhythmia characteristics on outcome. We reviewed the literature since 2005 for studies evaluating the impact of multiple risk factors on long-term outcomes and mortality after the Fontan. Studies focusing only on one or two risk factors (including arrhythmias) and those with a mean follow-up < 10 years were excluded. Of the 17 studies analyzed, only six mentioned rhythm at follow-up. Nine lumped all arrhythmias (tachyarrhythmia, bradyarrhythmia, paced rhythm, early and late arrhythmia) into one single category. Only eight of the 17 studies reported the incidence of tachyarrhythmias in detail and only two studies described bradyarrhythmias in detail as sinus or atrioventricular (AV) node dysfunction subgroups. Five studies reported on treatment of tachyarrhythmias including Fontan revision surgeries, catheter ablation, pacemaker placement and or the use of antiarrhythmic drugs. However, only one included information on the impact of treatment on outcomes. Out of 15 studies that conducted a multivariate analysis of Fontan outcomes, arrhythmia was included in the univariate model in 14 and in the multivariate model in 9. Overall, we found most studies on late outcomes after the Fontan do not include rhythm and arrhythmia characteristics in data collection and analysis. Incorporating more granular rhythm information in large databases and in multivariate analyses will help better determine and contextualize the impact of arrhythmias on outcomes after the Fontan.

Serial changes of systemic ventricular function and atrioventricular valve function in patients with failing Fontan

OBJECTIVES

This study investigated the longitudinal changes in ventricular function and atrioventricular valve function to clarify the timing and the mechanisms of failing Fontan.

METHODS

Patients who underwent total cavopulmonary connection between 1994 and 2023 were reviewed, and longitudinal echocardiographic examinations of ventricular function and atrioventricular valve regurgitation were analysed.

RESULTS

A total of 650 patients were included. The most frequent primary diagnosis was hypoplastic left heart syndrome in 175 patients. Dominant right ventricle was observed in 337 patients (51.8%). The median age at total cavopulmonary connection was 2.3 (1.8-3.3) years. Failing Fontan was observed in 78 patients (12%) during the median follow-up of 6.2 years. Among them, dominant right ventricle was observed in 51 patients (65.4%). Patients with protein-losing enteropathy or plastic bronchitis (n = 37) developed Fontan failure early (median 2.6 years post-total cavopulmonary connection). Still, patients maintained ventricular function (93.1% normal at 5 years) and atrioventricular valve competence (no case of moderate/severe regurgitation at 5 years) over time. Patients who developed failing Fontan associated with progression of heart failure (n = 41) had later onset (median 8.3 years post-total cavopulmonary connection) but indicated progressive ventricular dysfunction (68.3% normal at 5 years, 53.8% normal at 10 years) and atrioventricular valve regurgitation (12.3% moderate/severe at 5 years, 15.3% moderate/severe at 10 years).

CONCLUSIONS

Patients with failing Fontan indicated different serial ventricular and atrioventricular valve function profiles. Ventricular function was preserved in failing Fontan patients with protein-losing enteropathy or plastic bronchitis, whereas progressive ventricular dysfunction was observed in failing Fontan patients with heart failure.

Prevalence and clinical correlates and characteristics of "Super Fontan"

BACKGROUND

Super-Fontan (SF) is an excellent phenotype of patients with Fontan circulation and normal exercise capacity. This study aimed to clarify the prevalence and clinical correlates and characteristics of SF.

METHODS

We reviewed 404 Fontan patients who had undergone cardiopulmonary exercise testing, and the results were compared with clinical profiles.

RESULTS

Seventy-seven (19%) patients had SF, and the postoperative prevalence at 5, 10, 15, 20, and ≥ 25 years was 16 (35%), 30 (39%), 18 (19%), 13 (14%), and 0 (0%), respectively. Compared with non-SF, SF patients were younger (P < .001) and were mostly men (P < .05). SF was characterized by a current high arterial blood pressure and oxygen saturation (SaO2), low systemic ventricle (SV) end-diastolic pressure, favorable body composition, superior pulmonary function, preserved hepatorenal and hemostatic functions, and better glucose tolerance (P < .05-.001). Pre-Fontan better SV function, low pulmonary artery resistance, and high SaO2 were associated with current SF (P < .05-.01). Furthermore, positive trajectory of exercise capacity and high daily activity during childhood were associated with current adult SF (P < .05). During the follow-up, 25 patients died, and 74 patients were unexpectedly hospitalized. There was no death in the SF group, and the rate of hospitalization was 67% lower than that of the non-SF group (P < .01-.001).

CONCLUSIONS

The prevalence of SF gradually decreased over time. SF was characterized by preserved multi-end-organ function and an excellent prognosis. Pre-Fontan hemodynamics and post-Fontan childhood daily activity were associated with being adult SF.

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

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

Combined hepatocellular carcinoma-cholangiocarcinoma in a patient with Fontan-associated liver disease

We present a rare case of combined hepatocellular carcinoma-cholangiocarcinoma in a woman with a history of univentricular congenital heart disease requiring multiple corrective operations including Fontan procedure. During workup for elevated alpha fetal protein, a right hepatic lobe lesion was identified with biopsy showing poorly differentiated hepatocellular carcinoma. She underwent successful segment 5 liver resection. Final pathology demonstrated combined hepatocellular carcinoma-cholangiocarcinoma. She was treated with gemcitabine/oxaliplatin adjuvant chemotherapy and had no evidence of recurrent disease at her 12-month follow-up. To our knowledge, this is the first case reported in of successful treatment of this rare malignancy in the setting of Fontan-associated liver disease and highlights the importance of a robust screening protocol in this patient population. Semiannual screening for the development of primary liver malignancy should start by 10 years post-Fontan and continue until heart-liver transplantation may be performed. It is important to note that cirrhosis is not a pre-requisite for the development of hepatocellular carcinoma or cholangiocarcinoma in these patients.

Long-term Outcome of Fontan-Associated Protein-Losing Enteropathy: Treatment Modality and Predictive Factor of Mortality

We conducted the first retrospective study on Fontan-associated protein-losing enteropathy (PLE) in Korea. Fontan-associated PLE is still challenging to treat, although the survival rate has improved. There is no best treatment for PLE, and relapse occurs frequently. However, selected patients show promising results after various treatments. It would be helpful to identify the risk factors of mortality in patients with Fontan-associated PLE. High-risk patients should undergo comprehensive evaluations and receive more aggressive therapies for PLE. This study emphasizes the necessity for developing aggressive and individually targeted treatment strategies by sharing our long-term experience on Fontan-associated PLE in the current era.

Background and Objectives

Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE.

Methods

We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea.

Results

PLE occurred in 4.6% of the total 832 patients after the Fontan operation. After a mean period of 7.7 years after Fontan operation, PLE was diagnosed at a mean age of 11.6 years. The mean follow-up period was 8.9 years. The survival rates were 81.6% at 5 years and 76.5% at 10 years. In the multivariate analysis, New York Heart Association Functional classification III or IV (p=0.002), low aortic oxygen saturation (<90%) (p=0.003), and ventricular dysfunction (p=0.032) at the time of PLE diagnosis were found as predictors of mortality. PLE was resolved in 10 of the 38 patients after treatment. Among medical managements, an initial heparin response was associated with survival (p=0.043). Heparin treatment resulted in resolution in 4 patients. We found no evidence on pulmonary vasodilator therapy alone. PLE was also resolved after surgical Fontan fenestration (2/6), aortopulmonary collateral ligation (1/1), and transplantation (1/1).

Conclusions

The survival rate of patients with Fontan-associated PLE has improved with the advancement of conservative care. Although there is no definitive method, some treatments led to the resolution of PLE in one-fourth of the patients. Further investigations are needed to develop the best prevention and therapeutic strategies for PLE.

Identification of metabolomic profile related to adult Fontan pathophysiology

Background

Metabolic disorders are important pathophysiologies that can cause multiple organ dysfunction and worsen prognosis in Fontan patients. This study aimed to comprehensively evaluate the metabolomic profile of adult Fontan patients and characterize its pathophysiology in relation to 2 control groups.

Methods and Results

We performed metabolomic analysis of 31 plasma samples using capillary electrophoresis time-of-flight mass spectrometry. This observational cross-sectional study compared plasma metabolites of 14 heterogeneous adult Fontan patients with those of control groups, including 9 patients with congenital heart disease after biventricular repair and 8 normal healthy controls. Fontan patients exhibited significant differences in intermediate metabolite concentrations related to glycolysis, the tricarboxylic acid (TCA) cycle, and the urea cycle. The plasma concentrations of lactic acid, 2-oxoglutarate, isocitric acid, malic acid, cis-aconitic acid, arginine, citrulline, and the ratio of ornithine/citrulline showed significantly differences among the groups. Multiple logistic regression analysis with a stepwise selection-elimination method identified 2-oxoglutaric acid (odds ratio [OR] 1.98, 95% confidence interval [CI] 1.05–3.76) and cis-aconitic acid (OR 2.69, 95% CI 1.04–6.99) as independently associated with Fontan patients. After adjustment for the covariates of age and gender, 2-oxoglutaric acid (OR 1.97, 95% CI 0.98–3.93) and cis-aconitic acid (OR 3.88, 95% CI 0.99–15.2) showed remarkable relationships with Fontan patients.

Conclusions

The present findings suggest that abnormalities in the TCA cycle and amino acid metabolism are distinguishing features in the pathophysiology of Fontan patients. Future metabolomic studies will assist in developing biomarkers for the early prediction of “silent” Fontan pathophysiologies.

Development of a biventricular conversion program: A new paradigm

BACKGROUND

Borderline small ventricular size or technical issues precluding the use of both ventricles may lead to single ventricle palliation. Fontan complications have led some centers to look for alternatives to the traditional pathway. The objective of this study is to evaluate the essential philosophy and outcomes of a new biventricular (BiV) conversion program.

METHODS

The prospectively collected Children's Memorial Hermann Heart Institute Society of Thoracic Surgeon's Database was retrospectively reviewed between July 2017 and July 2020.

RESULTS

Thirteen patients met inclusion criteria and underwent BiV conversion during that time. The most frequent diagnosis was malposed great arteries and a ventricular septal defect (VSD) in 4 (31%) patients. Seven (54%) patients were in the first interstage, and 1 (8%) patient had already undergone a Fontan operation before their BiV conversion operation. One or more risk factors for single ventricle palliation (genetic syndrome ≥ moderate atrioventricular valve regurgitation ≥ moderate ventricular dysfunction, presence of signs of Fontan failure) were present in 3 (23%) patients. The median left ventricular end diastolic pressure increased from 5.5 mmHg (4-10 mmHg) to 10 mmHg (6-20 mmHg) postoperatively (p < .05). The right ventricular pressure (RVP) was estimated as less than half systemic in all six patients who were able to be estimated. At a median follow-up of 22.6 months (0.3-36.4 months), 12 (92%) patients are alive.

CONCLUSIONS

BiV conversion is feasible with reasonable short-term clinical outcomes. Mortality risk is low, but as seen in other studies, the risk of reintervention is high.

The mid-term outcome of Fontan conversion compared with primary total cavopulmonary connection

BACKGROUND

The indication of Fontan conversion (FC) from atriopulmonary connection (APC) to total cavopulmonary connection (TCPC) is unclear. We sought to analyze the mid-term outcome of prophylactic and therapeutic Fontan conversion compared with that of primary TCPC.

METHODS

Patients with a univentricular heart who underwent cardiac catheterization at >18 years of age between July 2005 and July 2019 were included and divided into three groups: symptomatic APC patients who underwent therapeutic FC (t-FC, n = 13), asymptomatic APC patients after prophylactic FC (p-FC, n = 15), and patients who had primary TCPC procedure (pTCPC, n = 24).

RESULTS

The mean last follow up was at the age of 32.0 ± 7.8, 26.8 ± 3.8, and 27.3 ± 7 years (p = 0.07) in t-FC, p-FC, and pTCPC, respectively. There was no late death. All of t-FC and 12 (80%) of p-FC cases underwent concomitant arrhythmic surgery. Consequently, five and four patients in t-FC and p-FC groups required pacemaker implantations mostly due to sinus node dysfunction. Thromboembolism was seen in 2 cases in both t-FC (15%) and p-FC (13%), and 1 case in pTCPC (4%) (p = 0.50). The last cardiac catheterization was performed at the age of 29.5 ± 8.5, 24.6 ± 3.8, and 26.3 ± 7.1 years (p = 0.11) in t-FC, p-FC, and pTCPC patients, respectively. There was no significant difference in central venous pressure, aortic pressure, and cardiac index among the three groups. There was no late supraventricular tachyarrhythmic event seen in t-FC and p-FC, whereas two patients in pTCPC had newly developed atrial flutter.

CONCLUSIONS

FC is a safe and feasible procedure to bring APC patients back onto the same track of primary TCPC patients in terms of hemodynamics as well as arrhythmia. The antiarrhythmic procedure should be carefully chosen because sinus node dysfunction can frequently occur and FC itself would reduce the risk of arrhythmia.

Incidence, Predictors, and Mortality in Patients With Liver Cancer After Fontan Operation

Background

Liver cancer (LC) is a serious late complication after the Fontan operation. However, the incidence, predictors, and prognosis remain unknown. The purpose of our study was to determine these clinical characteristics.

Methods and Results

We assessed liver function in 339 consecutive patients who had undergone the Fontan procedure from 2005 to 2019. LC was histologically diagnosed in 10 patients after a median period of 2.9 years (range: 0.3–13.8; median age: 29.9 years [range: 14.4–41.5 years]; overall median post–Fontan procedure follow‐up: 25.6 years [range: 13–32.1 years]), and the annual incidence was 0.89%. Over the entire post‐Fontan follow‐up period, the annual incidences of new‐onset LC in the second, third, and fourth decades were 0.14%, 0.43%, and 8.83%, respectively. The patients with LC had longer follow‐up periods, higher levels of AFP (α‐fetoprotein), and higher values of liver fibrosis indices (P<0.01–0.0001). Moreover, all indices were predictive of new‐onset LC (P<0.01–0.0001). The LC treatments were surgical resection (n=3), transarterial chemoembolization (n=3), radiofrequency ablation (n=2), and hospice care (n=2). During a median follow‐up of 9.4 months, 4 patients died; the survival rate at 1 year was 60%, and it was better among asymptomatic patients (P<0.01).

Conclusions

The LC incidence rapidly increased ≥30 years after the Fontan procedure, and liver fibrosis indices and AFP were predictive of new‐onset LC. These LC‐predictive markers should be monitored closely and mandatorily for early LC detection and better prognosis.

Changes in Heart Rate and Heart Rate Variability During Surgical Stages to Completed Fontan Circulation

Arrhythmia is related to heart rate variability (HRV), which reflects the autonomic nervous regulation of the heart. We hypothesized that autonomic nervous ganglia, located at the junction of the superior vena cava's entrance to the heart, may be affected during the bidirectional Glenn procedure (BDG), resulting in reduced HRV. We aimed to investigate changes in heart rate and HRV in a cohort of children with univentricular heart defects, undergoing stepwise surgery towards total cavopulmonary connection (TCPC), and compare these results with healthy controls. Twenty four hours Holter-ECG recordings were obtained before BDG (n = 47), after BDG (n = 47), and after total cavopulmonary connection (TCPC) (n = 45) in patients and in 38 healthy controls. HRV was analyzed by spectral and Poincaré methods. Age-related z scores were calculated and compared using linear mixed effects modeling. Total HRV was significantly lower in patients before BDG when compared to healthy controls. The mean heart rate was significantly reduced in patients after BDG compared to before BDG. Compared to healthy controls, patients operated with BDG had significantly reduced heart rate and reduced total HRV. Patients with TCPC showed reduced heart rate and HRV compared with healthy controls. In patients after TCPC, total HRV was decreased compared to before TCPC. Heart rate was reduced after BDG procedure, and further reductions of HRV were seen post-TCPC. Our results indicate that autonomic regulation of cardiac rhythm is affected both after BDG and again after TCPC. This may be reflected as, and contribute to, postoperative arrhythmic events.

Secondary sarcopenia assessed by computed tomography can predict hospitalization for heart failure in adults with Fontan circulation

BACKGROUND

Sarcopenia is one of the important predictors of heart failure (HF) in patients with cardiac problems. Skeletal muscle pump is important to maintain Fontan circulation. We aimed to quantify the volume of the psoas major muscle (PMM) and investigate whether it is relevant to HF hospitalization in adults with Fontan circulation.

METHODS

A total of 154 adults with Fontan circulation, and 30 age-matched adults were studied retrospectively. We identified secondary sarcopenia by measuring the PMM volume, using non-contrast abdominal computed tomography.

RESULTS

PMM indexed volume in Fontan patients was lower than controls (206.4+/-18.0 cc/m² vs 288.0+/-61.1 cc/m², p < 0.0001). In Fontan men, PMM indexed volume correlated with New York Heart Association functional class (NYHA FC). PMM indexed volume in Fontan women correlated with age, NYHA FC, and serum creatinine. Using a multivariate Cox hazards analysis, NYHA FC ≧3 was an important predictor of hospitalization due to HF in Fontan men. In Fontan women, NYHA FC ≧3, brain natriuretic peptide, PMM indexed volume, and protein losing enteropathy were important predictions of hospitalization due to HF. Among all Fontan patients, those with low PMM volumes had a poorer prognosis in HF [log rank p = 0.012 (men) and 0.0009 (women)].

CONCLUSIONS

PMM volume reduction has an adjunctive prediction of HF hospitalization in adults with Fontan circulation, particularly in Fontan females. Secondary sarcopenia may have a negative impact on the prognosis of HF in this population. The assessment of skeletal muscle mass also may be a comprehensive screening tool for multi-organ dysfunction in Fontan circulation.

Transplant and mechanical circulatory support in patients with adult congenital heart disease

Advances in surgery and pediatric care over the past decades have achieved improved survival for children born with congenital heart disease (CHD) and have produced a large, growing population of patients with adult congenital heart disease (ACHD). Heart failure has emerged as the leading cause of death and a major cause of morbidity among the ACHD population, while as little evidence supports the efficacy of guideline-directed medical therapies in this population. It is increasingly important that clinicians caring for these patients understand how to utilize mechanical circulatory support (MCS) in ACHD. In this review, we summarize the data on transplantation and MCS in the ACHD-heart failure population and provide a framework for how ACHD patients may benefit from advanced heart failure therapies like transplantation and MCS.

Modes of late mortality in patients with a Fontan circulation

OBJECTIVES

The mechanisms of attrition of the Fontan population have been poorly characterised and it is unclear whether some of the deaths are potentially preventable. We analysed the circumstances of late death in patients with a Fontan circulation, with a special focus on identifying lesions amenable to intervention that may have contributed to the decline of their circulation.

METHODS

Between 1975 and 2018, a total of 105 patients from a Bi-National Registry died beyond 1 year after Fontan completion, at a median age of 18.6 (IQR 13.8-26.0) years old, 12.7 (IQR 6.0-19.3) years after Fontan completion.

RESULTS

A total of 105 patients died-63 patients (60%) with an atriopulmonary (AP) Fontan, 21 patients (20%) with a lateral tunnel (LT) and 21 patients (20%) with an extracardiac conduit (ECC). 72 patients (69%) were reviewed within 2 years preceding death, with 32% (23/72) deemed to be clinically well. Fontan circulatory failure was the most common cause of death in 42 patients (45%). Other causes of death included sudden death/arrhythmia (19%), perioperative death (12%), neurological complication (7%) and thromboembolism (7%). All patients with an LT or ECC who died from Fontan failure had at least one surgical defect that was amenable to intervention at time of death.

CONCLUSIONS

Conventional clinical surveillance has been insensitive in detecting a significant proportion of patients at risk of late death. Fontan circulatory failure contributes to half of the late deaths. Patients with an LT or ECC Fontan who died with a clinical picture of circulation failure may have potentially correctable lesions.

Abnormal glucose metabolism in patients with Fontan circulation: Unique characteristics and associations with Fontan pathophysiology

BACKGROUND

Fontan patients exhibit a high prevalence of abnormal glucose metabolism (AGM). We aimed to characterize AGM and clarify its association with Fontan pathophysiology.

METHODS

We prospectively evaluated AGM with plasma glucose dynamics [mg/dL; fasting glucose (FPG), and maximum glucose increase (PG-spike)] during oral glucose tolerance test and hemoglobin A1c (HbA1c) in 276 consecutive Fontan patients (aged 19 ± 7 years). Of these, 176 patients had serial AGM assessments with a mean interval of 6.5 years.

RESULTS

Initial analysis revealed a high prevalence of impaired glucose tolerance (38.4%) and diabetes mellitus (DM) (4.7%), and positive family history, high HbA1c, and high central venous pressure independently predicted presence of DM. HbA1c was independently determined by hypersplenism and presence of DM (P < .05). Serial assessments revealed an increased PG-spike and a decreased HbA1c (P < .001 for both). Prevalence of DM increased (6.3% to 10.3%), and positive family history, high liver enzymes, and AGM predicted new onset of DM (P < .05 for all). Twenty-one patients died during 7.1-year follow-up. FPG (P < .01) and PG-spike (P < .05) independently predicted all-cause mortality. Particularly, patients with FPG ≤ 74 and/or PG-spike ≥85 had a mortality rate 8.7 times higher than those without (P = .0129).

CONCLUSIONS

AGM progressed even in young adult Fontan patients, and HbA1c showed limited predictive value for progression. Oral glucose tolerance test plays important roles in uncovering unique Fontan AGM as well as predicting all-cause mortality.