Incidence, pathophysiology, and treatment of failing Fontan after the total cavopulmonary connection.

BACKGROUND: Failing Fontan poses a significant clinical challenge. This study aims to improve patients' outcomes by comprehensively understanding the incidence, pathophysiology, risk factors, and treatment of failing Fontan after total cavopulmonary connection. METHODS: We performed a retrospective analysis of patients who underwent total cavopulmonary connection at the German Heart Center Munich between 1994 and 2022. The onset of failing Fontan was defined as: protein-losing enteropathy, plastic bronchitis, NYHA class IV, NYHA class III for > one year, unscheduled hospital admissions for heart failure symptoms, and evaluation for heart transplantation. RESULTS: Among 634 patients, 76 patients presented with failing Fontan, and the incidence was 1.48 per 100 patient-years. Manifestations included protein-losing enteropathy (n = 34), hospital readmission (n = 28), NYHA III (n = 18), plastic bronchitis (n = 16), evaluation for heart transplantation (n = 14), and NYHA IV (n = 4). Risk factors for the onset of failing Fontan were dominant right ventricle (p = 0.010) and higher pulmonary artery pressure before total cavopulmonary connection (p = 0.004). A total of 72 interventions were performed in 59 patients, including balloon dilatation/stent implantation in the total cavopulmonary connection pathway (n = 49) and embolization of collaterals (n = 24). Heart transplantation was performed in four patients. The survival after the onset of Fontan failure was 77% at 10 years. Patients with failing Fontan revealed significantly higher zlog-NT-proBNP levels after onset compared to those without (p = 0.021). CONCLUSIONS: The incidence of Fontan failure was 1.5 per 100 patient years. Dominant right ventricle and higher pulmonary artery pressure before total cavopulmonary connection were significant risks for the onset of failing Fontan. Zlog-NT-proBNP is only a late marker of Fontan failure.

Innominate Vein Turn-down Procedure for Failing Fontan Circulation.

After the Fontan, systemic venous hypertension induces pathophysiologic changes in the lymphatic system that can result in complications of pleural effusion, ascites, plastic bronchitis, and protein losing enteropathy. Advances in medical therapy and novel interventional approaches have not substantially improved the poor prognosis of these complications. A more physiological approach has been developed by decompression of the thoracic duct to the lower pressure common atrium with a concomitant increase of preload. Diverting the innominate vein to the common atrium increases the transport capacity of the thoracic duct, which in most patients enters the circulation at the left subclavian-jugular vein junction. Contrary to the fenestrated Fontan circulation, in which the thoracic duct is drained into the high pressure Fontan circulation, turn down of the innominate vein to the common atrium effectively decompresses the thoracic duct to the lower pressure system with "diastolic suctioning" of lymph. Innominate vein turn-down may be considered for medical-refractory post-Fontan lymphatic complications of persistent chylothorax, plastic bronchitis, and protein losing enteropathy. Prophylactic innominate vein turn-down may also be considered at time of the Fontan operation for patients that are higher risk for lymphatic complications.

Heart Transplantation and Mechanical Circulatory Support in Adults with Congenital Heart Disease.

PURPOSE OF REVIEW: To assess current management strategies for advanced heart failure in adults with congenital heart disease, including heart transplantation and mechanical circulatory support. RECENT FINDINGS: Current data demonstrate that adults with CHD generally experience higher short-term mortality after heart transplantation and MCS implantation, but enjoy superior long-term survival. Such patients are nonetheless less likely to receive a transplant than non-ACHD peers due to a variety of factors, including lack of applicability of current listing criteria to HF in ACHD. MCS is underutilized in ACHD, but provides similar quality of life benefits for ACHD and non-ACHD patients alike. Heart failure in ACHD is complex and difficult to treat, and both heart transplantation and mechanical circulatory support are often challenging to implement in this patient population. However, long-term results are encouraging, and existing data supports increasing use of MCS and transplant earlier in their disease course. Multidisciplinary care is critical to success in these complex patients.

Extracardiac Fontan fenestration using the SafeSept transseptal guidewire and snare-controlled diabolo-shaped covered-stent placement.

Transcatheter Fontan fenestration is a valuable option in situations of prolonged pleural drainage or low cardiac output in patients with failing Fontan circulation. This procedure relies on controlled baffle perforation without separation of the Fontan circuit from the pulmonary venous atrium, and placement of an accurately sized covered stent. We report a novel technique for transcatheter extracardiac Fontan fenestration using the SafeSept transseptal guidewire® and snare-controlled diabolo-shaped covered stent placement.

Risk factors and serological markers of liver cirrhosis after Fontan procedure.

Liver cirrhosis (LC), which may result in hepatic failure or cancer, has been reported in patients after Fontan procedure. The purpose of this study was to clarify the frequency and histological characteristics of LC, and to evaluate the risk factors and serological markers of LC with Fontan circulation. Retrospective review of contrast-enhanced CT scans (CT) of the liver was carried out in 57 patients after Fontan procedure. Patients were divided into two groups: LC group (n = 31) and no LC group (n = 26). Age at Fontan procedure, duration after Fontan procedure, catheterization data, and history of failing Fontan circulation were compared between groups. Serological data including γ-GTP and hyaluronic acid were compared. Histology of autopsy specimens was assessed when available. Duration after Fontan procedure was significantly longer in LC group than no LC group. History of failing Fontan circulation was more frequent in LC group than in no LC group. There was no correlation between type of procedure (APC/Bjork/lateral tunnel/TCPC) and LC in this series. Serum hyaluronic acid, γ-GTP, and Forns index were significantly higher in LC group. Significant risk factors for LC were duration after Fontan procedure (>20 years). In autopsy specimens, histopathological changes of LC were observed predominantly in the central venous area. LC diagnosed with CT is frequent in patients long after Fontan procedure, especially after 20 years. Hyaluronic acid and γ-GTP could be useful markers to monitor the progression of liver fibrosis in Fontan patients.

Modified Technique to Create Diabolo Stent Configuration.

Diabolo stent configuration aids in stent positioning, stability, and creating a controlled defect with a predetermined size. A number of techniques to create the diabolo configuration have been previously described. The indications for creating a controlled "defect" are rapidly growing and include the Fontan circulation, patients with severe end-stage pulmonary hypertension, restrictive atrial communication in the setting of hypoplastic right or left heart syndrome, and diastolic left heart failure. We describe an alternative technique using a prefabricated readily available tool (gooseneck snare) to create a diabolo stent configuration. The chosen balloon expandable stent is mounted on a 5-mm gooseneck snare centered on an angioplasty catheter larger than 5 mm diameter. When deployed, the snare restricts the central waist to 5 mm and both ends expand to a larger diameter creating a dumbbell/diabolo configuration. A total of six diablo stent configurations were successfully implanted in four patients with failing Fontan physiology; five to create a transcatheter fenestration and one to relieve atrial septal restriction. Data expressed as median and IQR. Their weight was 24.8 kg (19.6-46.95), and age years was 9.2 (6.28-13.23). There were no complications and a consistent diabolo configuration with a 5-mm central waist was created in all patients. The snare serves as a sterile, preconfigured, radiopaque, readily available tool of adequate length and strength, to create consistent diabolo stent configuration without any modifications. This technique is a simple, reproducible, and easy to learn.

Effects of systemic ventricular assist in failing Fontan patients: a theoretical analysis using a computational model.

Mechanical circulatory support is a potential treatment for failing Fontan patients. In this study, we performed a theoretical analysis using a computational model to clarify the effects of systemic ventricular assist device (VAD) in failing Fontan patients. Cardiac chambers and vascular systems were described using the time-varying elastance model and modified Windkessel model, respectively. A VAD was simulated as a nonlinear function. In systolic and diastolic ventricular dysfunction and atrioventricular valve regurgitation models, systemic VAD increased the cardiac index and decreased the central venous pressure (CVP). However, in the high pulmonary vascular resistance model, CVP became extremely high above 15 mmHg to maintain the cardiac index when the pulmonary vascular resistance index (PVRI) was above 5 Wood units m2. In Fontan patients with ventricular dysfunction or atrioventricular valve regurgitation, systemic VAD efficiently improves the hemodynamics. In Fontan patients with PVRI of > 5 Wood units m2, systemic VAD seems ineffective.

Validating the Concept of Mechanical Circulatory Support with a Rotary Blood Pump in the Inferior Vena Cava in an Ovine Fontan Model.

Right-sided mechanical support of the Fontan circulation by existing devices has been compounded by the cross-sectional design of vena cava anastomosis to both pulmonary arteries. Our purpose was to investigate whether increasing inferior vena cava (IVC) flow with a rotary blood pump in the IVC only in an ovine animal model of Fontan would lead to acceptable superior vena cava (SVC) pressure. To achieve this, a Fontan circulation was established in four female sheep by anastomosing the SVC to the main pulmonary artery (MPA) and by interposing a Dacron graft between the IVC and the MPA. A rotary blood pump was then introduced in the graft, and the effect of incremental flows was observed at increasing flow regimen. Additionally, to stimulate increased pulmonary resistance, the experience was repeated in each animal with the placement of a restrictive band on the MPA distally to the SVC and Dacron graft anastomosis. Circulatory support of IVC flow alone increased the systemic cardiac output significantly, both with and without banding, indicating the feasibility of mechanical support of the Fontan circulation by increasing the flow only in the inferior vena cava. The increase in SVC pressure remained within acceptable limits, indicating the potential effectiveness of this mode of support. The findings suggest that increasing the flow only in the inferior vena cava is a feasible method for mechanical support of the Fontan circulation, potentially leading to an increase in cardiac output with acceptable increases in superior vena cava pressure.

Case Report: Transcatheter interventional procedure to innominate vein turn-down procedure for failing fontan circulation.

Fontan physiology creates a chronic state of decreased cardiac output and systemic venous congestion, leading to liver cirrhosis/malignancy, protein-losing enteropathy, chylothorax, or plastic bronchitis. Creating a fenestration improves cardiac output and relieves some venous congestion. The anatomic connection of the thoracic duct to the subclavian-jugular vein junction exposes the lymphatic system to systemic venous hypertension and could induce plastic bronchitis. To address this complication, two techniques have been developed. A surgical method that decompresses the thoracic duct by diverting the innominate vein to the atrium, and a percutaneous endovascular procedure that uses a covered stent to create an extravascular connection between the innominate vein and the left atrium. We report a novel variant transcatheter intervention of the innominate vein turn-down procedure without creating an extravascular connection in a 39-month-old patient with failing Fontan circulation complicated by plastic bronchitis and a 2-year post-intervention follow-up.

Staged Acclimatization in a Failing Fontan by AFR in AFR: Ever-Decreasing Circles.

We describe serial implantation of atrial flow regulator (AFR) devices in the Fontan fenestration of a 4-year-old patient. Initially, the fenestration size was decreased using a 6/5 AFR, resulting in improved saturations and hemodynamics. One year later, further improvement was achieved by placing a 4/10 AFR inside the original device. (Level of Difficulty: Advanced.).

Laparoscopic surgery in a child with a failing Fontan circulation.

A child with early failure of a Fontan circulation was listed for cardiac transplantation and then developed a subhepatic abscess. Surgical drainage was deemed necessary after the failure of an attempted percutaneous procedure. Following a multidisciplinary discussion, a laparoscopic technique was chosen to optimise postoperative recovery. To our knowledge, the literature does not describe any case of laparoscopic surgery in a patient with a failing Fontan circulation. This case report highlights the physiological variations involved with this management strategy, discusses the implications and risks, and offers some recommendations.

CA125: a new biomarker in patients with Fontan circulation.

INTRODUCTION AND OBJECTIVES: Patients with Fontan circulation (FC) have a high incidence of clinical complications. However, no biomarker is able to accurately stratify risk. The aim of this study was to analyze the relationship between biomarkers and clinical complications, including carbohydrate antigen 125 (CA125) for the first time, and to propose a risk estimation based on a combination of biomarkers. METHODS: Cross-sectional study of patients with FC. The clinical endpoint was the combination of heart failure, atrial arrhythmias, veno-venous fistulae, protein-losing enteropathy, or plastic bronchitis. Demographic, clinical, and laboratory variables were analyzed, including CA125, NT-proBNP, renal and liver function, and red cell distribution width (RDW). We performed univariate and multivariate analyses of the relationship between these variables and the composite endpoint. Cutoff values were calculated by ROC curves. RESULTS: We included 56 patients (27.4±7.8 years). A total of 34% showed the composite endpoint, with significantly higher CA125 levels (30.1 IU/mL vs 12.6 IU/mL; P=.001). In the multivariate model, the biomarkers related to the endpoint were LnCA125 (OR, 5.1; 95%CI, 1.2-22), RDW (OR, 1.8; 95%CI, 1.1-3.1), and FIB4 (OR, 38, 95%CI, 1.7-855). The cutoff points were CA125 ≥ 20 U/mL, FIB4 ≥ 0.75, and RDW ≥ 14.5%, and the probability of the occurrence of the endpoint was 81% if ≥ 2 biomarkers were elevated. CONCLUSIONS: CA125 elevation is associated with a higher prevalence of complications in patients with Fontan-type circulation. CA125 levels ≥ 20U/mL, FIB4 ≥ 0.75 and RDW ≥ 14.5% identify with a high probability the clinical failure of FC.

Thoracic lymphatic anomalies in patients with univentricular hearts: correlation of morphologic findings in isotropic T2-weighted MRI with the outcome after fontan palliation.

Objectives: In this study we examined the correlation between the extent of thoracic lymphatic anomalies in patients after surgical palliation by total cavopulmonary connection (TCPC) and their outcome in terms of clinical and laboratory parameters. Materials and methods: We prospectively examined 33 patients after TCPC with an isotropic heavily T2-weighted MRI sequence on a 3.0 T scanner. Examinations were performed after a solid meal, slice thickness of 0.6 mm, TR of 2400 ms, TE of 692 ms, FoV of 460 mm, covering thoracic and abdominal regions. Findings of the lymphatic system were correlated with clinical and laboratory parameters obtained at the annual routine check-up. Results: Eight patients (group 1) showed type 4 lymphatic abnormalities. Twentyfive patients (group 2) presented less severe anomalies (type 1-3). In the treadmill CPET, group 2 reached step 7.0;6.0/8.0 vs. 6.0;3.5/6.8 in group 1 (p = 0.006*) and a distance of 775;638/854 m vs. 513;315/661 m (p = 0.006*). In the laboratory examinations, group 2 showed significantly lower levels of AST, ALT and stool calprotectin as compared to group 1. There were no significant differences in NT-pro-BNP, total protein, IgG, lymphocytes or platelets, but trends. A history of ascites showed 5/8 patients in group 1 vs. 4/25 patients in group 2 (p = 0.02*), PLE occurred in 4/8 patient in group 1 vs. 1/25 patients in group 2 (p = 0.008*). Conclusion: In the long-term follow-up after TCPC, patients with severe thoracic and cervical lymphatic abnormalities showed restrictions in exercise capacity, higher liver enzymes and an increased rate of symptoms of imminent Fontan-failure such as ascites and PLE.

Surgical management of failing Fontan circulation: results from 30 cases with 285 patient-years follow-up.

OBJECTIVES: Fontan patients are known to suffer from clinical attrition over the years, which has been characterized as Fontan failure. We sought to evaluate the clinical outcomes of such Fontan patients undergoing surgical management in a 25-year, single-centre experience. METHODS: A retrospective single-centre analysis of patients undergoing surgical treatment for failing Fontan between 1995 and 2020, including any reoperations when ventricular function was preserved, or a heart transplant (HTx), when ventricular contractility was impaired. We analysed survival, indications for surgery and early and late complication rates. RESULTS: We collected 30 patients (mean age 24.7 years) who required surgery after a mean time of 19.3 years from the original Fontan procedure: Fontan conversion in 21 (70%, extracardiac conduit in 19, lateral tunnel in 2), a HTx in 4 (13.3%) and other reoperations in 5 (16.7%). The most common indications for surgery were tachyarrhythmias (63.3%) and severe right atrial dilatation (63.3%). Overall survival at the 1-, 5-, 10- and 20-year follow-up examinations were 75.9% [95% confidence interval (CI): 91.4-60.4%], 75.9% (95% CI: 91.4-60.4%), 70% (95% CI: 78-52%) and 70% (95% CI: 78-52%), respectively. The most frequent complications were postoperative tachyarrhythmias (50%) and late Fontan-associated liver disease (56.5%). HTx and Fontan conversion provided comparably good outcomes compared to other reoperations (P = 0.022). CONCLUSIONS: Surgery for failing Fontan can be performed effectively with overall good long-term survival. However, early and late morbidities are still a significant burden. Because other reoperations performed when patients presented with contraindications for a HTx have carried high mortality, close clinical follow-up is mandatory, and an earlier indication for Fontan conversion or a HTx is advisable to optimize outcomes.

Cavopulmonary support with a modified cannulation technique in a failing Fontan patient.

Failing Fontan patients present a unique challenge for mechanical circulatory support. We report on a 17-year-old patient with Fontan failure and preserved ventricular function who underwent mechanical cavopulmonary support using a novel cannulation technique.

Biventricular conversion after Fontan completion: A preliminary experience.

OBJECTIVE: To assess the feasibility and outcomes of biventricular conversion following takedown of Fontan circulation. METHODS: Retrospective analysis of patients who had takedown of Fontan circulation and conversion to biventricular circulation at a single center from September 2007 to April 2020. Failing Fontan physiology was defined as Fontan circulation pressure >15 mm Hg and/or the presence of associated complications. RESULTS: Biventricular conversion was performed in 23 patients at a median age of 10.0 (7.5-13.0) years. Indications included failing Fontan physiology in 15 (65%) and elective takedown in 8 (35%) patients. A subset of patients (n = 6) underwent procedures for staged recruitment of the nondominant ventricle before conversion. Median z score of end-diastolic volume of borderline ventricle before takedown was -2.3 (-3.3, -1.3). Hypoplastic left heart syndrome (P < .01) and sub-/aortic stenosis (P < .01) were more common in these patients. Biventricular conversion with or without staged ventricular recruitment led to a significant increase in indexed end-diastolic volume (P < .01), indexed end-systolic volume (P < .01), and ventricular mass (P < .01) of the nondominant ventricle (14 right, 9 left ventricle). There were 5 (22%) deaths (1 [4%] early death). All who underwent elective biventricular conversion survived, whereas 2-year survival rate for patients with a failing Fontan circulation was 72.7% (95% confidence interval, 37%-90%). The overall, 3-year reoperation-free survival was 86.7% (95% confidence interval, 56%-96%). Left dominant atrioventricular canal defect (P < .01) and early era of biventricular conversion (P = .02) were significant predictors for mortality. CONCLUSIONS: A primary as well as a staged biventricular conversion is feasible in patients who have had previous Fontan procedure. Although this provides an alternative to transplantation in patients with failing Fontan, outcomes are worse in those with failing Fontan compared with elective takedown of Fontan circulation. Optimal timing needs further evaluation.

Case report: Heart Mate III for systemic right ventricular support in a patient with hypoplastic left heart syndrome.

Ventricular assist device implantation presents a possible bridge to heart transplantation for patients with failing Fontan physiology. However, evidence regarding outcome and possible pitfalls associated with the Fontan circulation is still insufficient. We describe the course of a 13-year-old male, who was born with hypoplastic left heart syndrome and underwent HeartMate III implantation due to refractory failure of the systemic right ventricle.

Intraventricular Flow Simulations in Singular Right Ventricles Reveal Deteriorated Washout and Low Vortex Formation.

PURPOSE: Patients with a functionally univentricular heart represent one of the most common severe cardiac lesions with a prevalence of 3 per 10,000 live births. Hemodynamics of the singular ventricle is a major research topic in cardiology and there exists a relationship between fluid dynamical features and cardiac behavior in health and disease. The aim of the present work was to compare intraventricular flow in single right ventricle (SRV) patients and subjects with healthy left hearts (LV) through patient-specific CFD simulations. METHODS: Three-dimensional real-time echocardiographic images were obtained for five SRV patients and two healthy subjects and CFD simulations with a moving mesh methodology were performed. Intraventricular vortex formation and vortex formation time (VFT) as well as the turbulent kinetic energy (TKE) and ventricular washout were evaluated. RESULTS: The results show significantly lower values for the VFT and the TKE in SRV patients compared with healthy LV subjects. Furthermore, vortex formation does not progress to the apex in SRV patients. These findings were confirmed by a significantly lower washout in SRV patients. CONCLUSIONS: The study pinpoints the intriguing role of intraventricular flows to characterize performance of SRVs that goes beyond standard clinical metrics such as ejection fraction.

Failing Fontan.

Dr. O.P. Yadava, CEO & Chief Cardiac Surgeon, National Heart Institute, New Delhi, India, and Editor-in-Chief, Indian Journal of Thoracic and Cardiovascular Surgery, in conversation with Prof. Richard Jonas, Paediatric Cardiac Surgeon from Washington DC, USA, on Failing Fontan.

Lumped parameter models for two-ventricle and healthy and failing extracardiac Fontan circulations.

Fontan circulations are surgical strategies to treat infants born with single ventricle physiology. Clinical and mathematical definitions of Fontan failure are lacking, and understanding is needed of parameters indicative of declining physiologies. Our objective is to develop lumped parameter models of two-ventricle and single-ventricle circulations. These models, their mathematical formulations and a proof of existence of periodic solutions are presented. Sensitivity analyses are performed to identify key parameters. Systemic venous and systolic left ventricular compliances and systemic capillary and pulmonary venous resistances are identified as key parameters. Our models serve as a framework to study the differences between two-ventricle and single-ventricle physiologies and healthy and failing Fontan circulations.