Early and long-term outcomes following cardiac surgery for patients with heterotaxy syndrome

Objective

Heterotaxy syndrome is a complex multisystem abnormality historically associated with high morbidity and mortality. We sought to evaluate the early and long-term outcomes after cardiac surgery in heterotaxy syndrome.

Methods

This is a single-center retrospective review of patients with heterotaxy syndrome undergoing single-ventricle palliation or primary or staged biventricular repair from 1998 to 2018. Patients were stratified by single ventricle versus biventricular physiology, and the severity of atrioventricular valve regurgitation. Demographics, anatomic characteristics, and early and late outcomes, including the length of stay, mortality, and surgical or catheter reinterventions, were analyzed.

Results

Among 250 patients, 150 (60%) underwent biventricular repair. In-hospital mortality was 7.6% (n = 19). Median follow-up was 5.2 (range, 0-16) years. Among survivors to discharge, mortality was 19% (n = 44) and reintervention was 52% (n = 120). Patients with moderate/severe atrioventricular valve regurgitation were older (32 vs 16 months, P = .02), were more likely to experience adverse events during their index surgical admission (72% vs 46%, P < .001), and had longer in-hospital length of stay (20 vs 12 days, P = .009). Among patients with moderate to severe atrioventricular valve regurgitation, single-ventricle palliation is associated with a greater risk of unplanned reintervention compared with patients undergoing biventricular repair (hazard ratio, 2.13; CI, 1.10-4.12; P = .025).

Conclusions

There was no significant difference in early or late outcomes in single-ventricle versus biventricular repair strategies in heterotaxy. In the subgroup of patients with moderate/severe atrioventricular valve regurgitation, patients who underwent single-ventricle palliation were 2.5 times more likely to need a late reintervention compared with those undergoing biventricular repair.

Trends and outcomes of heart transplantation in adults with congenital heart disease

OBJECTIVES

Heart transplantation for adult congenital heart disease is complicated and associated with challenging pretransplant support, long waiting and high early post-transplant mortality. We explored if surgical and medical advances and allocation system changes have affected outcomes.

METHODS

From United Network for Organ Sharing database, adults with congenital heart disease listed for heart transplantation were queried. To explore practice and outcome trends, patients were divided into 4 eras (eras 1-3: nearly 3 equal periods from 1992 to 2018, era 4: after 2018, corresponding with new allocation system). Univariate and multivariable analysis was performed to evaluate outcomes.

RESULTS

A total of 2737 patients were listed. There was gradual increase in listed and transplanted patients, along with significant increase in use of mechanical support, simultaneous kidney and liver transplantation. While proportion of transplanted remained constant, there was decrease in proportion delisted/died after listing (P = 0.01) and waiting list duration (P = 0.01), especially in era 4. Thirty-day post-transplant mortality remains high; however, it has significantly improved starting era 3 (P = 0.01). Current survival at 1-year and 5-years is 85% and 65%, with improvement mainly related to decreased early death. On multivariable analysis, factors associated with survival were lower glomerular filtration rate (hazard ratio = 0.99, P = 0.042), bilirubin (hazard ratio = 1.17, P<0.001) and mechanical ventilation (hazard ratio = 2.3, P=0.004).

CONCLUSIONS

Heart transplantation in adults with congenital heart disease is increasing, along with added complexity, higher usage of pretransplant mechanical support and simultaneous organ transplantation. Despite that, more complex patients do not experience worse outcomes. Early mortality improved but remains high. New donor allocation system allowed shorter waiting time and higher proportion transplanted without altering early mortality.

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.

Oxygen inhalation decreases the central venous pressure in adult patients late after Fontan operations

BACKGROUND

Elevated central venous pressure (CVP) and decreased arterial oxygen saturation (SaO2) are the characteristics of patients after Fontan operations and determine morbidity and mortality in the long-term. Oxygen inhalation therapy theoretically increases SaO2 and may decrease the elevated CVP in these patients. However, there is no previous study to support this hypothesis. This study aimed to determine the acute effects of oxygen inhalation on the hemodynamics of adult patients late after Fontan operations using cardiac catheterization.

METHODS

This study enrolled 58 consecutive adult patients (median age, 30 years; female, n = 24) who had undergone Fontan operations. We assessed the hemodynamic changes during oxygen inhalation (2 L/min) with a nasal cannula in cardiac catheterization. We divided the studied patients into two groups according to the reduction in CVP during oxygen inhalation using the median value: responders (>2 mmHg) and non-responders (≤2 mmHg). Clinical characteristics of the responders to oxygen inhalation were investigated with uni- and multivariate analyses.

RESULTS

SaO2 increased from 93.3 % (91.3-94.5 %) to 97.5 % (95.2-98.4 %) (p < 0.001) and CVP decreased from 12 mmHg (11-14 mmHg) to 10 mmHg (9-12 mmHg) (p < 0.001) after oxygen inhalation. There was a weak but significant correlation between the increase in SaO2 and the decrease in CVP (R = 0.29, p = 0.025). Pulmonary blood flow increased from 4.1 L/min (3.5-5.0 L/min) to 4.4 L/min (3.7-5.3 L/min) (p = 0.007), while systemic blood flow showed no significant changes. A multivariate analysis revealed that high baseline CVP was associated with a larger decrease in CVP (>2 mmHg) after oxygen inhalation.

CONCLUSIONS

Oxygen inhalation increased SaO2 and decreased CVP, especially in patients with high baseline CVP. Further studies with home oxygen therapy are needed to investigate the long-term effects of oxygen inhalation in adult patients who underwent Fontan operations.

Hemoadsorption Contribution in Failing Fontan Pediatric Heart Transplantation

INTRODUCTION

A systemic inflammatory response is triggered in patients undergoing cardiothoracic surgery with cardiopulmonary bypass (CPB). This response is particularly evident in pediatric patients, especially those of low weight and after undergoing long CPB, and can severely impair the surgical result. Adsorptive blood purification techniques have been proposed to limit this systemic inflammatory response. To test its efficacy, we added the hemoadsorption filter Jafron HA 380 to CPB in a much compromised pediatric patient who underwent heart transplantation.

METHODS

A 10-year-old single ventricle patient previously treated with Fontan operation was listed for heart transplantation due to the evidence of failing Fontan condition. He experienced many episodes of cardiac arrest and underwent heart transplantation in much compromised general and hemodynamic conditions. The hemoadsorption filter Jafron HA 380 was used for all the duration of CPB, and the inflammatory biomarker interleukin 6 (IL-6) was assayed.

RESULTS

Postoperative outcome was uneventful and comparable to that of elective pediatric heart transplantation. IL-6 levels showed an impressive postoperative reduction, and after 2 days, the IL-6 level was comparable with a typical uneventful post-transplant course.

CONCLUSIONS

The use of hemoadsorption filter can contribute to improve the pediatric transplant results, especially in very high-risk patients.

Mitochondrial dysfunction is associated with the severity of liver fibrosis in patients after the Fontan operation

The gold standard for determining the severity of liver disease in Fontan patients is now liver biopsy. Since it is an invasive procedure, this study determined the possibility of applying mitochondrial function from isolated peripheral blood mononuclear cells (PBMCs) as a non-invasive indicator of liver fibrosis. Fontan patients (n = 37) without known liver disease were analysed cross-sectionally. Patients were classified according to their histology using the METAVIR score as follows; F0/F1-no/mild fibrosis; F2-moderate fibrosis; and F3/F4-cirrhosis. Peripheral blood mononuclear cells were assessed for mitochondrial activity and apoptosis. This study did not find any significant differences in cardiac function among the groups according to liver histology. Interestingly, our findings indicated a significant decrease in maximal respiration and spare respiratory capacity, in both the moderate (F2) and cirrhosis (F3/F4) groups compared with the group without significant fibrosis (F0/F1). Moreover, the cirrhosis group exhibited higher levels of apoptosis and lower levels of live cells, compared with both the moderate and no significant fibrosis groups. In conclusion, the degree of liver fibrosis in Fontan patients is strongly correlated with mitochondrial dysfunction in PBMCs. Mitochondrial function and apoptosis could potentially serve as novel markers for tracking the progression of liver fibrosis in these patients.

Management of Junctional Rhythm in Patients After the Fontan Operation: A Multicenter Congenital Cardiology Survey

Sinus node dysfunction with concomitant junctional rhythm (JR) is frequently observed among Fontan patients and has been recognized as a contributor to heart failure. The impact and management of JR is unclear. A survey was mailed to all members of the Pediatric and Congenital Electrophysiology society (PACES) and members were asked to forward the questionnaire to their non-electrophysiology colleagues. Responses were received from 154 physicians (88 electrophysiologists (EP's) and 66 non-EP's (46 pediatric cardiologists and 20 adult congenital cardiologists). There were few differences in the response between EP's and non-EP's. Overall, 57% recommended an annual ambulatory ECG (AECG). A significant majority (80%) opted to continue to follow patients with significant periods of JR on AECG as long as the patients were asymptomatic, and showed no echocardiographic signs of cardiac decompensation. However, 84% would place a pacemaker in a patient with JR who was having open chest surgery for other reasons. Finally, pacemaker placement would be performed by 91% if a patient with JR showed signs of heart failure. Most congenital cardiologists would not recommend pacemaker placement in asymptomatic Fontan patients with JR. Further studies are needed on the Fontan population to determine the impact of SND and JR on longer term outcomes and to determine the role and optimal timing of pacemaker placement in these patients.

Assessment of ventricular function after total cavo-pulmonary derivation in adult patients: Interest of global longitudinal strain

Ventricular dysfunction is the most frequent complication in adult patients post-Fontan completion. Through this work, we aim to evaluate ventricular systolic function by conventional echographic parameters and by global longitudinal strain (GLS) to determine the prediction of early ventricular systolic dysfunction. This is a prospective monocentric study enrolling 15 clinically stable adult Fontan patients with preserved ejection fraction (EF). Myocardial deformation study by GLS with speckle tracking technique in addition to a standard Doppler transthoracic echocardiography (TTE) was performed. Cardiac magnetic resonance imaging (CMR) was also performed. A comparison of echocardiographic and CMR parameters was made. In comparison to CMR-derived EF, we found a significant correlation with GLS and TTE-derived EF (P=0.003 and 0.014). We divided our population into two groups based on the cut-off value of 50% of CMR derived EF. Comparison of GLS in both groups showed a significant correlation (P=0.003). A cut-off value of -13.3% showed sensitivity of 67% and specificity of 100%. GLS has a moderate diagnostic value for systolic myocardial dysfunction in the population of adult patients with Fontan circulation.

Duplex ultrasound abnormalities of the lower limb veins might precede clinical venous reflux signs in post-Fontan adolescents and young adults

OBJECTIVE

After the Fontan operation (ie, direct anastomosis of the caval veins to the pulmonary arteries, constituting right ventricular bypass circulation), high central venous pressure can lead to peripheral venous stasis and venous valvar insufficiency. We hypothesized that post-Fontan patients are at a higher risk of developing lower extremity venous lesions detectable using duplex ultrasound, even if clinical signs of chronic venous disease might not be evident.

METHODS

A total of 87 transplantation-free survivors after the Fontan procedure who reached adolescence or young adulthood (current age, 15-30 years) participated in a leg vein duplex ultrasound study. The median age at the Fontan procedure, median age at the vein study, and median interval between the two were 3.65 years (interquartile range [IQR], 3.1-5.3 years), 21.7 years (IQR, 18.9-24.7 years), and 16.6 years (IQR, 14.9-19.4 years), respectively. Duplex ultrasound scanning was performed using a venous ultrasound imaging system (Logiq P7; GE Healthcare). The patients were categorized according to the presence of venous reflux (VR) in the superficial, deep, or perforating venous systems: no VR, superficial VR (SVR), deep VR (DVR), perforating VR (PVR), and a combination of multiple venous systems. Correlation of the duplex ultrasound-detected venous lesions with clinical severity using the modified CEAP (clinical, etiological, anatomical, pathophysiological) classification was analyzed using Spearman's correlation analysis.

RESULTS

Leg pain was reported by 48 of 87 patients (55.2%). The duplex ultrasound findings for the cohort were no VR in 21 patients (24.1%), SVR in 22 (25.3%), isolated PVR in 21 (24.1%), and reflux of multiple venous systems in 23 patients, including SVR and PVR in 19, DVR and PVR in 1, and SVR, PVR, and DVR in 3 patients. Although the patients with advanced venous lesions detected by duplex ultrasound tended to have a higher CEAP clinical class (P < .001), VR of any venous system on duplex ultrasound was present even in patients with a lower CEAP clinical class. The CEAP clinical class was C0 for 66 patients (76%), and VR of any venous system was present on duplex ultrasound in 66 patients (76%).

CONCLUSIONS

The prevalence of lower extremity venous lesions detected by duplex ultrasound is strikingly high in post-Fontan adolescents and young adults, and duplex ultrasound-detected venous abnormalities can precede clinical manifestations. Early detection and timely intervention for leg vein problems are mandatory for post-Fontan patients, especially for those considered to have risk factors for developing chronic lower extremity venous disease.

The prognostic role of liver volumetry in Fontan patients

BACKGROUND AND HYPOTHESES

High venous pressures and associated hepatic congestion are important drivers for Fontan-associated liver disease. The prognostic significance of hepatomegaly as a marker of congestion however is not well defined and is further explored in this research study.

METHODS

Fontan patients who have had liver ultrasound scans were identified from the Prince Sultan Cardiac Centre Fontan Database and had their anatomic, surgical, clinical histories abstracted from the electronic medical records following institutional ethics approval. Liver volumes were determined retrospectively from reviewing individual US images, and these, divided into tertiles, were analysed in the context of the predefined endpoints of (i) Primary - death or heart or liver transplantation, or (ii) Secondary - combined endpoint of death, transplantation, arrhythmia, or protein-losing enteropathy.

RESULTS

Mean indexed liver volumes for the entire cohort (n = 199) were 1065.1 ± 312.1 ml/m2, range 387 to 2071 ml/m2. Patients with the largest liver volumes (highest tertile) were less likely to have a functioning fenestration compared to those in the lowest tertile 44% versus 56% p = 0.016 and experienced the highest burden of mortality and heart or heart-liver transplantation, p = 0.016, and were more likely to reach the composite endpoint of death, protein-losing enteropathy, arrhythmia, or transplantation, p = 0.010. Liver volumes had an overall predictive accuracy for the combined outcome of 61% (CI 53%, 67%, p = 0.009).

CONCLUSIONS

Liver volumetry may serve as a potentially important congestion biomarker for adverse outcomes after the Fontan operation.

Predictors of prolonged pleural effusion after Fontan operation

Prolonged pleural effusion is a fairly common condition which has considerable impact on complicated and longer hospital stays after Fontan surgery. Identifying the patient population prone to have pleural effusions is still seeking for an answer. This study is to determine the variables that may predict prolonged pleural effusion according to the data of 69 patients who underwent Fontan operation between June 2018 and December 2020 and survived to date. Prolonged pleural effusion was defined as the need for a chest tube for more than 7 days. Two patient groups, with and without prolonged effusion, were compared in terms of pre-, peri-, and post-operative variables. The patients were subdivided into "high-risk" and "low-risk" groups based on the pre-operative catheterisation data. The most frequent main diagnosis was tricuspid atresia (n: 13, 19%). Among 69 patients, 28 (40%) had prolonged pleural effusion whereas 11 (16%) had effusions that lasted longer than 14 days. Ten patients among prolonged effusion group (35%) had pulmonary atresia coexistent with the main diagnosis. Fontan operation was performed in 6 patients (8.7%) over the age of 10, and 4 of these patients (67%) had prolonged pleural effusion. Among numerous variables, statistical significance between the two groups was achieved in pre-operative mean pulmonary artery pressure, post-operative albumin, C-reactive protein levels, length of hospital stay, duration of chest tube drainage, and amount of effusion per day. Early recognition and treatment strategies with routine medical protocol use remain to be the cornerstone for the management of post-operative prolonged pleural effusions after Fontan surgery.

Transcatheter thrombectomy of acute pulmonary embolism in an adult Fontan patient: a case report

Background

The Fontan operation is a well-described palliative procedure for functional single-ventricle patients. This population has an increased risk of thrombo-embolic events. Adequate imaging, and therefore diagnosis, requires an understanding of the unique anatomy and physiology of a Fontan. Optimal strategies for the prevention and treatment of thrombo-embolic complications in the Fontan population are poorly defined.

Case summary

A 28-year-old female with a history of Ebstein anomaly of the tricuspid valve status post-Fontan presented with chest pain and acute hypoxia. Computed tomographic angiography (CTA) reported a submassive pulmonary embolism (PE). She was initiated on a heparin drip. Catheterization demonstrated elevated Fontan pressures and a large thrombus in the right lower pulmonary artery that was removed with an aspiration device. The patient was transitioned to a direct oral anticoagulant (DOAC) following the procedure.

Discussion

Thrombotic complications are common in the adult Fontan population. Given the morbidity and mortality associated with this complication, the use of proper imaging techniques is imperative. Traditional CTA imaging for PE in Fontan patients often has contrast filling defects related to their anatomy and physiology. Utilization of adequate imaging techniques helps decrease cost and additional radiation exposure. In addition, it avoids inappropriate hospitalization, need for anticoagulation, and potential need for catheterization toconfirm or exclude the presence of PE. For Fontan patients with a thrombus, prior event, and no contraindications, current guidelines recommend oral anticoagulation with a vitamin K antagonist; however, there are increasing data on the use of DOACs in this population.

Pulmonary Complications in Patients With Fontan Circulation: JACC Review Topic of the Week

The Fontan operation has resulted in significant improvement in survival of patients with single ventricle physiology. As a result, there is a growing population of individuals with Fontan physiology reaching adolescence and adulthood. Despite the improved survival, there are long-term morbidities associated with the Fontan operation. Pulmonary complications are common and may contribute to both circulatory and pulmonary insufficiency, leading ultimately to Fontan failure. These complications include restrictive lung disease, sleep abnormalities, plastic bronchitis, and cyanosis. Cyanosis post-Fontan procedure can be attributed to multiple causes including systemic to pulmonary venous collateral channels and pulmonary arteriovenous malformations. This review presents the unique cardiopulmonary interactions in the Fontan circulation. Understanding the cardiopulmonary interactions along with improved recognition and treatment of pulmonary abnormalities may improve the long-term outcomes in this growing patient population. Interventions focused on improving pulmonary function including inspiratory muscle training and endurance training have shown a promising effect post-Fontan procedure.

Associations Between Characteristics of Individuals With Fontan Circulation With Blood and Urine Biomarkers of Kidney Injury and Dysfunction

Background Fontan circulation is associated with kidney injury and dysfunction, often unappreciated until Fontan circulatory failure. We hypothesized that cystatin C-estimated glomerular filtration rate (eGFR) would identify chronic kidney disease more frequently and that urine kidney injury biomarkers would be higher with declining Fontan physiological features. Methods and Results We enrolled 100 ambulatory individuals. Blood and urinary laboratory measurements were compared with demographics and clinically obtained data. Different eGFR equations were used for individuals aged ≥19 years and <19 years. Chronic kidney disease was defined as eGFR <90 mL/min per 1.73 m². Median (25th-75th percentile) age was 19 (14-26) years, and 43% were female patients. Cystatin C eGFR detected chronic kidney disease (37%) in more patients than creatinine eGFR (11%). Cystatin C eGFR was positively associated, and skeletal muscle mass was negatively associated, with creatinine eGFR in both univariate (cystatin C eGFR β=0.44±0.12, P=0.0006; skeletal muscle mass β=-0.72±0.32, P=0.03) and multivariable analysis (cystatin C eGFR β=0.43±0.12, P=0.0005; skeletal muscle mass β=-0.69±0.29, P=0.02). Urine neutrophil gelatinase-associated lipocalin concentration correlated with Fontan pressure (r=0.28; P=0.04), ventricular end-diastolic pressure (r=0.28; P=0.04), and body fat mass (r=0.26; P=0.03). Conclusions Cystatin C eGFR identified more kidney dysfunction, likely attributable to creatinine eGFR being confounded by skeletal muscle mass. Elevated urine neutrophil gelatinase-associated lipocalin was associated with worse Fontan hemodynamics and higher percentage body fat, suggesting that higher venous pressure and higher adiposity are associated with ongoing kidney injury.

Magnetic resonance three-dimensional steady-state free precession imaging of the thoracic duct in patients with Fontan circulation and its relationship to outcomes

BACKGROUND

Lymphatic complications are common in patients with Fontan circulation. Three-dimensional balanced steady-state free precession (3D bSSFP) angiography by cardiovascular magnetic resonance (CMR) is widely used for cardiovascular anatomical assessment. We sought to determine the frequency of thoracic duct (TD) visualization using 3D bSSFP images and assess whether TD characteristics are associated with clinical outcomes.

METHODS

This was a retrospective, single-center study of patients with Fontan circulation who underwent CMR. Frequency matching of age at CMR was used to construct a comparison group of patients with repaired tetralogy of Fallot (rTOF). TD characteristics included maximum diameter and a qualitative assessment of tortuosity. Clinical outcomes included protein-losing enteropathy (PLE), plastic bronchitis, listing for heart transplantation, and death. A composite outcome was defined as presence of any of these events.

RESULTS

The study included 189 Fontan patients (median age 16.1 years, IQR 11.0-23.2 years) and 36 rTOF patients (median age 15.7 years, IQR 11.1-23.7 years). The TD diameter was larger (median 2.50 vs. 1.95 mm, p = 0.002) and more often well visualized (65% vs. 22%, p < 0.001) in Fontan patients vs. rTOF patients. TD dimension increased mildly with age in Fontan patients, R = 0.19, p = 0.01. In Fontan patients, the TD diameter was larger in those with PLE vs. without PLE (age-adjusted mean 4.11 vs. 2.72, p = 0.005), and was more tortuous in those with NYHA class ≥ II vs. class I (moderate or greater tortuosity 75% vs. 28.5%, p = 0.02). Larger TD diameter was associated with a lower ventricular ejection fraction that was independent of age (partial correlation = - 0.22, p = 0.02). More tortuous TDs had a higher end-systolic volume (mean 70.0 mL/m2 vs. 57.3 mL/m2, p = 0.03), lower creatinine (mean 0.61 mg/dL vs. 0.70 mg/dL, p = 0.04), and a higher absolute lymphocyte count (mean 1.80 K cells/µL vs. 0.76 K cells/µL, p = 0.003). The composite outcome was present in 6% of Fontan patients and was not associated with TD diameter (p = 0.50) or tortuosity (p = 0.09).

CONCLUSIONS

The TD is well visualized in two-thirds of patients with Fontan circulation on 3D-bSSFP images. Larger TD diameter is associated with PLE and increased TD tortuosity is associated with an NYHA class ≥ II.

Therapy of Patients with Cardiac Malposition

Positional abnormalities per se do not require treatment, but in their place, the accompanying pulmonary pathology in dextroposition patients and pathophysiologic hemodynamic abnormalities resulting from multiple defects in patients with cardiac malposition should be the focus of treatment. At the time of the first presentation, treating the pathophysiologic aberrations caused by the defect complex, whether it is by improving the pulmonary blood flow or restricting it, is the first step. Some patients with simpler or single defects are amenable to surgical or transcatheter therapy and should be treated accordingly. Other associated defects should also be treated appropriately. Biventricular or univentricular repair dependent on the patient's cardiac structure should be planned. Complications in-between Fontan stages and after conclusion of Fontan surgery may occur and should be promptly diagnosed and addressed accordingly. Several other cardiac abnormalities unrelated to the initially identified heart defects may manifest in adulthood, and they should also be treated.

Clinical aspects and targeted inspiratory muscle training in children and adolescents with Fontan circulation: a randomized controlled trial

Background

Since 1968, thousands of patients with a morphologically or functionally univentricular heart have been treated with a total cavopulmonary connection/Fontan operation. Because of the resulting passive pulmonary perfusion, blood flow is assisted by the pressure shift during respiration. Respiratory training is known to improve exercise capacity and cardiopulmonary function. However, there are limited data on whether respiratory training can also improve physical performance after Fontan surgery. The aim of the present study was to clarify the effects of six months of daily home-based inspiratory muscle training (IMT) aimed at increasing physical performance by strengthening respiratory muscles, improving lung function and peripheral oxygenation.

Methods

In this non-blinded randomized controlled trial, the effects of IMT on lung capacity and exercise capacity were measured in a large cohort of 40 Fontan patients (25% female; 12.3±2.2 years) who were under regular follow-up by the outpatient clinic of the Department of Congenital Heart Defects and Pediatric Cardiology of the German Heart Center Munich. After a lung function test and a cardiopulmonary exercise test, patients were randomly assigned in a parallel arm design to either an intervention group (IG) or a control group (CG) via stratified and computer-generated letter randomization from May 2014 to May 2015. The IG completed a daily, telephone-monitored IMT of three sets of 30 repetitions for six months with an inspiratory resistive training device (POWERbreathe medic^®), the CG continued their usual daily activities without an IMT until the second examination within the timeframe of November 2014 until November 2015.

Results

After six months of IMT, lung capacity values in the IG (n=18) did not increase significantly compared to the CG [n=19; ΔFVC: IG: 0.21±0.16 l vs. CG 0.22±0.31 l; P=0.946 (CI: -0.16, 0.17); ΔFEV1: CG: 0.14±0.30 vs. IG: 0.17±0.20 P=0.707 (CI: -0.20, 0.14)]. Exercise capacity did not improve significantly, yet the maximum workload achieved trended to improve with an increase of 14% in the IG vs. 6.5% in the CG [P=0.113 (CI: -15.8, 1.76)]. There was a significant increase of oxygen saturation at rest in the IG compared to the CG [IG: 3.31%±4.09% vs. CG: 0.17%±2.92%, P=0.014 (CI: -5.60, -0.68)]. Compared to the CG, the mean oxygen saturation at peak exercise no longer dropped below 90% in the IG. This observation is thus not statistically significant, yet of clinical relevance.

Conclusions

The results of this study show benefits of an IMT in young Fontan patients. Even if some data are not statistically significant, they may still be clinically relevant and may contribute to a multidisciplinary approach in patient care. IMT should therefore be an additional target and integrated into the training program to improve the prognosis of Fontan patients.

Trial Registration

German Clinical Trials Register; DRKS.de; registration ID: DRKS00030340.

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.

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.

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.

Efficacy of a phosphodiesterase type 5 inhibitor on the pulmonary artery index and postoperative hemodynamics after a Fontan operation

There have been no reports regarding the influence of a change in the pulmonary artery index before or after a Fontan operation. Moreover, the factors that might affect the change in the pulmonary artery index are unclear. This was a retrospective study, which included 94 patients who underwent a Fontan operation. We divided the patients into two groups according to the change in the pulmonary artery index before and after the Fontan operation: the increased pulmonary artery index group (n = 51) and decreased pulmonary artery index group (n = 43). The pulmonary artery index after the Fontan operation was significantly higher in the increased pulmonary artery index group than decreased pulmonary artery index group (p < 0.0001). The central venous pressure (p < 0.0001) and pulmonary vascular resistance (p = 0.007) were significantly lower in the increased pulmonary artery index group. The mixed venous oxygen saturation was significantly higher in the increased pulmonary artery index group (p < 0.0001). The pulmonary artery index was more increased in the patients who were administered a phosphodiesterase type 5 inhibitor than in those who were not (p = 0.03). The change in the pulmonary artery index reflected the hemodynamics after a Fontan operation during the short term. In that respect, phosphodiesterase type 5 inhibitors might be involved in the process.

Hepatocellular carcinoma diagnosed in a patient who had Fontan operation 30 years ago: a case report

The Fontan operation is performed in patients with a single ventricle. As the systemic venous return is directly connected to the pulmonary circulation during this procedure, chronic hepatic congestion is induced, leading to Fontan-associated liver disease (FALD) including liver cirrhosis and hepatocellular carcinoma (HCC). In this report, we present a case of HCC diagnosed in a patient who underwent the Fontan operation 30 years ago. The patient underwent regular surveillance for FALD, which revealed a 4 cm-sized hepatic mass with elevated serum alpha-fetoprotein. After surgical treatment, there was no evidence of HCC recurrence during 3 years of follow-up. As the risk of HCC and Fontan-associated liver cirrhosis increases with the duration elapsed since the operation, regular surveillance should be emphasized. Serial follow-up of serum alpha-fetoprotein levels and abdominal imaging are necessary to achieve early and accurate diagnosis of HCC in post-Fontan patients.

Preoperative N-terminal pro-brain natriuretic peptide is associated with Fontan outcomes

OBJECTIVE

The role of preoperative N-terminal pro-brain natriuretic peptide level in patient outcomes after the Fontan operation remains unclear.

METHODS

The medical records of all patients who underwent their first Fontan operation from June 2011 to October 2019 in our tertiary referral pediatric cardiac center were retrospectively reviewed. Preoperative hemodynamic factors and N-terminal pro-brain natriuretic peptide were analyzed to test the association of mortality and morbidity.

RESULTS

We enrolled 110 patients (men/women 62/48; median age, 4.1 [3.4, 5.8] years; median follow-up period, 4.28 [2.31, 6.71] years). Almost all operations were extracardiac conduits (98.2%). Primary outcomes of death, Fontan takedown, and heart transplantation were observed in 9 patients (8.2%). Abnormal ventricular contractility, elevated preoperative pulmonary artery pressure, high pulmonary vascular resistance index, and high log₁₀ N-terminal pro-brain natriuretic peptide level were associated with poor outcomes.

SECONDARY OUTCOMES

atrioventricular valve regurgitation moderate or greater, elevated pulmonary artery pressure, high pulmonary vascular resistance index, and high log₁₀ N-terminal pro-brain natriuretic peptide level were associated with rehospitalization due to heart failure. Multivariable Cox regression analysis revealed that log₁₀ N-terminal pro-brain natriuretic peptide was the only significant predictor of all primary and secondary outcomes. A scoring system including factors of pulmonary artery pressure, pulmonary vascular resistance index, and N-terminal pro-brain natriuretic peptide was established, and the risk stratification is associated with outcomes after the Fontan operation.

CONCLUSIONS

High preoperative N-terminal pro-brain natriuretic peptide was associated with poor outcomes after the Fontan operation.

Role of intrapulmonary artery septation in univentricular hearts

The optimal management of functionally univentricular hearts with a significant unbalanced pulmonary blood flow is unclear. The role of cavopulmonary shunt in the rehabilitation of hypoplastic pulmonary arteries is limited. Intrapulmonary artery septation is a technique, wherein a systemic-to-pulmonary artery shunt provides an additional source of blood flow to rehabilitate the hypoplastic pulmonary artery. We report a case of functionally univentricular heart with hypoplastic left pulmonary artery following a cavopulmonary shunt in whom intrapulmonary artery septation resulted in adequate growth of the left pulmonary artery.

National outcomes of the Fontan operation with endocardial cushion defect

BACKGROUND

The traditional outcomes of the Fontan operation (FO) in endocardial cushion defect (ECD) patients have been suboptimal. Previous studies have been limited by the smaller number of ECD patients, longer study period with an era effect, and do not directly compare short-term outcomes of FO in ECD patients with non-ECD patients. Our study aims to address these shortcomings.

METHODS

A retrospective analysis of the Kids Inpatient Database (2009, 2012, and 2016) for the FO was done. The groups were divided into those who underwent FO with ECD as compared to non-ECD diagnosis. The data were abstracted for demographics, clinical characteristics, and operative outcomes. Standard statistical tests were used.

RESULTS

Three thousand three hundred eighty patients underwent the FO of which 360 patients (11%) were FO-ECD. ECD patients were more likely to have Down syndrome, Heterotaxy syndrome, transposition/DORV, and TAPVR as compared to non-ECD patients. FO-ECD had a higher discharge-mortality (2.84% vs. 0.45%, p = .04). The length of stay (16 vs. 13 days, p = .05) and total charges incurred ($283, 280 vs. $234, 106, p = .03) for the admission were higher in the FO-ECD as compared to non-ECD patients. In multivariable analysis, ECD diagnosis, cardiac arrest, acute kidney injury, and postoperative hemorrhage were predictors of mortality.

CONCLUSION

Contemporary outcomes for FO are excellent with very low overall operative mortality. However, the outcomes in ECD patients are inferior with higher operative mortality than in non-ECD patients. The occurrence of postoperation complications and a diagnosis of ECD were predictive of a negative outcome.

Torsion of wandering spleen after Fontan operation in a patient with situs inversus: a rare complication

Torsion of wandering spleen after the Fontan operation with situs inversus is rare.Here, we report the case of a 6-year-old girl with a single ventricle and complete situs inversus who developed torsion of wandering spleen due to splenomegaly caused by post-operative haemodynamics of the Fontan operation. The platelet count was suggested to be useful in predicting splenic torsion.

Liver nodules after the Fontan operation: role of the computerised tomography scan

Currently, there is an increasing prevalence of liver nodules in patients following the Fontan operation. The appropriate non-invasive modalities have been applied to assess a diagnosis of Fontan-associated liver disease. The aims of this study were to determine the prevalence and associated factors for the presence of liver nodules using CT scan. A cross-sectional study of 34 patients older than 15 years of age was recruited. Ultrasound upper abdomen, ultrasound liver elastography, and CT scan of the upper abdomen were performed after the Fontan operation. The median age of patients was 20 years (range 14-36 years). The median age at the Fontan operation was 7 years (range 5-17 years) and the duration after the Fontan operation was 12 years (range 4-22 years). The prevalence of liver nodules was 62% as detected by CT scans. Hepatic vein pressure in patients with liver nodules was significantly higher than in those without liver nodules. Hepatic vein pressure above 13 mmHg was a factor associated with liver nodules. There was little agreement between the ultrasound of the upper abdomen and CT scan of the upper abdomen in the evaluation of liver nodules. Hepatic pressure was the only associated factor for the occurrence of liver nodules in patients following the Fontan operation. The prevalence of liver nodules was very high after the Fontan operation. The upper abdomen CT scan should be performed for the surveillance of liver nodules in every Fontan patient over the age of 15 years.

Predicting Hemodynamic Performance of Fontan Operation for Glenn Physiology using Computational Fluid Dynamics: Ten Patient-specific Cases

Single ventricle hearts have only one ventricle that can pump blood effectively and the treatment requires three stages of operations to reconfigure the heart and circulatory system. At the second stage, Glenn procedure is performed to connect superior vena cava (SVC) to the pulmonary arteries (PA). For the third and most complex operation, called Fontan, an extracardiac conduit is used to connect inferior vena cava (IVC) to the PL and thereafter no deoxygenated blood goes to the heart. Predicting Hemodynamic Performance of Fontan Operation using computational fluid dynamics (CFD) is hypothesized to improve outcomes and optimize this treatment planning in children with single-ventricle heart disease. An important reason for this surgical planning is to reduce the development of pulmonary arteriovenous malformations (PAVM) and the need to perform Fontan revisions. The purpose of this study was to develop amodel for Fontan surgical planning and use this model to compare blood circulation in two designed graft types of Fontan operation known as T-shape and Y-graft. The functionality of grafts was compared in terms of power loss (PL) and hepatic flow distribution (HFD), a known factor in PAVM development. To perform this study, ten single-ventricle children with Glenn physiology were included and a CFD model was developed to estimate the blood flow circulation to the left and right pulmonary arteries. The estimated blood flow by CFD was compared with that measured by cardiovascular magnetic resonance. Results showed that there was an excellent agreement between the net blood flow in the right and left pulmonary arteries computed by CFD and CMR (ICC= 0.98, P-value ≥0.21). After validating the accuracy of each CFD model, Fontan operations using T-shape and Y-graft conduits were performed in silico for each patient and the developed CFD model was used to predict the post-surgical PL and HFD. We found that the PL in the Y-graft was significantly lower than in the T-shape (P-value ≤0.001) and HFD was significantly better balanced in Y-graft compared to the T-shape (P-value=0.004).

Fontan procedure on deep hypothermic circulatory arrest: Short-term results and technique

Background

Various operative strategies are described for the Fontan procedure. In this study, we describe our short-term results and technique of Fontan procedure on cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA).

Methods

This was a retrospective study of 32 patients, median age of 6 years (4-19 years) and median weight of 20 kg (13-51 kg), who underwent Fontan procedure on CPB and DHCA from July 2016 to July 2021.

Results

The median CPB time was 125 min (77-186 min), the median DHCA time was 42 min (27-50 min), and the median Fontan pressure was 14 mmHg (10-18 mmHg). The median time to extubation was 4 h (1-20 h), the duration of chest tube drainage was 8 days (5-24 days), and the median intensive care unit stay was 4 days (3-8 days). The presence of heterotaxy was associated with longer duration of pleural drainage (P = 0.01). There was no operative mortality and no major adverse events such as seizures, gross neurological deficits, or arrhythmias in the postoperative period.

Conclusions

Fontan procedure can be safely performed on CPB and DHCA with good operative results. This operative strategy may be used in special circumstances like in patients with situs and systemic venous anomalies and those requiring repair of a complex intracardiac defect. Long-term follow-up will be required to evaluate if this strategy has any impact on the neurodevelopmental outcome and the long-term sequelae of Fontan.

Fontan operation for tricuspid atresia with absent pulmonary valve: a case series

Combined tricuspid atresia and absent pulmonary valve with dysplasia of the right ventricular myocardium is a very rare congenital heart anomaly with a poor prognosis. We present three cases of this rare disease that reached the Fontan operation without prior surgical intervention of the right ventricle or pulmonary artery; no right ventriclar dilation was detected. All patients had uneventful post-operative courses.

Focal segmental glomerulosclerosis in patients after Fontan operation: is this a Fontan-associated renal disease?

Despite acceptable survival for Fontan operation, there are concerns about late complications affecting the major organs. We herein present two cases of adults after Fontan operation who developed focal segmental glomerulosclerosis. These cases suggest that focal segmental glomerulosclerosis is owing to haemodynamic incompetence associated with Fontan operation, including congestion, hypoxia, and hyperviscosity, which may be called Fontan-associated renal disease.

Screening modalities for the diagnosis of Fontan-associated liver disease: evidence from the past for future development

Approximately 70,000 patients who have undergone the Fontan operation worldwide survive into adulthood, however the majority of these patients are faced with long-term post-operative complications due to specific hemodynamic changes. Fontan-associated liver disease (FALD) is a challenging complication characterized by various spectra. Of these, liver congestion and liver fibrosis potentially lead to cirrhosis and liver nodules. The most serious condition associated with the development of liver nodules is hepatocellular carcinoma. Various non-invasive modalities including blood tests, ultrasound scans of the upper abdomen, ultrasound elastography of the liver, computed tomography scans, magnetic resonance imaging and magnetic resonance elastography of the liver have been used as alternatives to liver biopsies for FALD assessment in post-Fontan patients. To date, a detailed understanding of the pathophysiology and natural history of these patients, and the most appropriate modality for the effective investigation of this condition is incomplete. In this comprehensive review, reports regarding the currently available screening modalities used in the detection of FALD are summarized and discussed. The findings of this review, including identification of any current knowledge gaps, can pave the way for the development of effective future strategies in the surveillance and ultimately the treatment of post-Fontan patients.

Hemodynamic Impact of Atrial Pacing in Patients with Fontan Physiology and Junctional Rhythm: A Cardiac Catheterization Study

Sinus node dysfunction is a common problem and adversely impacts patients who have undergone the Fontan operation. In Fontan patients with an adequate junctional escape rhythm, the benefit of atrial pacing to restore atrioventricular synchrony remains unclear. Data were collected retrospectively on all Fontan patients with junctional rhythm who underwent atrial pacing during cardiac catheterization. Hemodynamics were obtained at baseline and after atrial pacing for 5-10 min. Seven patients, mean age 10 years (3-21) were studied. The type of Fontan was extracardiac in 6 and lateral tunnel in one. Patients were paced at 10 bpm faster than their junctional rate. With pacing, there was a significant decrease in left atrial pressure from (mean ± SEM) 8.8 ± 2.6 to 5.5 ± 2.9 mmHg (p = 0.02), a significant increase in cardiac index from 2.7 ± 0.8 to 3.5 ± 1 L/min/m² (p = 0.01) and pulmonary blood flow from 2.1 ± 0.6 to 2.7 ± 0.7 L/min/m² (p = 0.001), and no significant change in pulmonary artery pressure, from 13.4 ± 2.8 to 12.4 mmHg ± 3.6 (p = 0.06) or pulmonary vascular resistance from 2.1 ± 0.86 to 3.25 ± 1.9 WU × M2 (p = 0.1). In Fontan patients with junctional rhythm, atrial pacing decreased the left atrial pressure, increased cardiac output and did not significantly change the pulmonary artery pressure. Our study supports further investigation into the utility of prophylactic atrial pacemaker implantation in Fontan patients with significant durations of JR on ambulatory monitoring.

Long-Term Outcomes After an Individualized Strategy in Patients with Pulmonary Atresia and Intact Ventricular Septum

This retrospective cohort study aimed to explore the long-term outcomes of an individualized strategy in patients with pulmonary atresia and intact ventricular septum (PAIVS). We analyzed survival and reintervention rates and identified risk factors for outcomes in patients with PAIVS treated based on individual right heart structures between 1979 and 2019. Ninety-five patients were included in this study. The z-scores of the pulmonary annulus, tricuspid annulus, and right ventricular end-diastolic volume were - 3.30 (- 15.15 to 1.83), - 0.70 (- 4.65 to 2.33), and - 1.51 (- 6.35 to 1.18), respectively. Right ventricular-dependent coronary circulation occurred in 15% of the patients. Among the 63 patients attempting biventricular strategy at first, 55 patients achieved biventricular circulation, 3 patients had one-and-a-half circulation, and 4 patients died perioperatively. Among the 33 patients attempting univentricular strategy at first, 10 patients died before the completion of Fontan operation, 17 patients (48%) accomplished Fontan operation, and 5 patients waited for Fontan operation. In one patient, conversion to biventricular circulation occurred. During the follow-up period of 720 person-years, the 20-year survival rate was significantly higher in patients with biventricular circulation than in those patients with univentricular circulation (93% vs. 67%, P < 0.001). Freedom from reintervention rates at 20 years was significantly lower in patients with biventricular circulation than in those patients with univentricular circulation (29% vs. 72%, P < 0.001). The pulmonary annulus z-score was an independent risk factor for reintervention in patients with biventricular circulation. Patients with biventricular circulation had an acceptable survival rate, but a high reintervention rate. Meanwhile, patients with univentricular circulation had high mortality before the completion of Fontan operation, although the reintervention rate was relatively low.

Cardiac Imaging in Patients After Fontan Palliation: Which Test and When?

The Fontan operation represents the final stage of a series of palliative surgical procedures for children born with complex congenital heart disease, where a "usual" biventricular physiology cannot be restored. The palliation results in the direct connection of the systemic venous returns to the pulmonary arterial circulation without an interposed ventricle. In this unique physiology, systemic venous hypertension and intrathoracic pressures changes due to respiratory mechanics play the main role for propelling blood through the pulmonary vasculature. Although the Fontan operation has dramatically improved survival in patients with a single ventricle congenital heart disease, significant morbidity is still a concern. Patients with Fontan physiology are in fact suffering from a multitude of complications mainly due to the increased systemic venous pressure. Consequently, these patients need close clinical and imaging monitoring, where cardiac exams play a key role. In this article, we review the main cardiac imaging modalities available, summarizing their main strengths and limitations in this peculiar setting. The main purpose is to provide a practical approach for all clinicians involved in the care of these patients, even for those less experienced in cardiac imaging.

Pulmonary Arteriovenous Fistulae After Fontan Operation: Incidence, Clinical Characteristics, and Impact on All-Cause Mortality

BACKGROUND

The Fontan operation is a surgical procedure used in children with univentricular hearts. Pulmonary arteriovenous fistulae (PAVF) is a major complication after a Fontan operation. However, the incidence and related clinical pathophysiology of PAVF remain unclear.

PURPOSE

This study aimed to clarify the incidence of PAVF, its clinical characteristics, and its influence on all-cause mortality.

METHODS AND RESULTS

We serially assessed the presence of PAVF using pulmonary artery angiography and/or contrast echocardiography during catheterization in 391 consecutive patients who underwent the Fontan procedure and compared the results with the Fontan pathophysiology and all-cause mortality. PAVF developed in 36 patients (9.2%), including 30 diffuse- and six discrete-PAVF types. The PAVF-free rates at 1, 5, 10, 15, 20, and ≥25 years after Fontan operation were 97, 96, 93, 88, 87, and 83%, respectively. The mean arterial blood oxygen saturation (SaO₂) in patients with diffuse PAVF at each corresponding postoperative stage were 90, 91, 91, 91, 89, and 88%, respectively, indicating lower SaO₂ levels than those in patients without PAVF (all p < 0.01). However, there was no difference in the SaO₂ levels between patients with discrete PAVF and those without PAVF. During a median follow-up period of 2.9 years after the last catheterization, 31 patients, including 12 patients with PAVF, died. Patients with PAVF, especially those with diffuse PAVF, had a higher mortality rate (p = 0.01) than those without PAVF (hazard ratio: 3.6, 95% confidence interval: 1.6-7.8, p = 0.0026).

CONCLUSION

Patients who underwent Fontan surgery had an increased incidence of PAVF as they aged. Discrete PAVF did not influence SaO₂ or mortality, whereas the presence of diffuse PAVF caused hypoxia and was associated with all-cause mortality.

Fontan Circulation Might be Associated with Peripartum Cardiomyopathy: A Review of Mechanistic and Clinical Aspects

Fontan operation has been defined as a palliative surgery connecting systemic venous return and pulmonary circulation in patients with certain forms of complex congenital heart disease (CHD). Fortunately, it has improved overall survival and chance of successful pregnancies among these patients. However, Fontan circulation (FC), as a potential trade-off, might be associated with specific late or post-gestational complications, including peripartum cardiomyopathy (PPCM) largely through its adverse effects on the placenta and inflammation-oxidation stress. Importantly, diagnosis of superimposed PPCM in women with FC might be a diagnostic challenge, requiring a high index of suspicion. Accordingly, the present paper aims to highlight the potential association of FC with PPCM evolution largely based on certain mechanistic and clinical perspectives.

Late Fontan failure in adult patients is predominantly associated with deteriorating ventricular function

BACKGROUND

The Fontan operation is a palliative procedure and a substantial number of patients eventually experiences late Fontan circulation failure. Previous concepts of Fontan failure implicate increasing pulmonary vascular resistance (PVR) as a key contributor to late circulatory failure. However, data to support this assumption are sparse. We sought to characterize longitudinal hemodynamic and echocardiographic findings in adult failing Fontan patients.

METHODS

We performed a retrospective cohort study in adult Fontan patients, identifying patients with Fontan failure. Hemodynamic, echocardiographic and clinical data were recorded.

RESULTS

Of 173 adult patients (median follow-up after Fontan 20.2 years [IQR 15.7-24.3]), 48 (28%) showed signs of clinical Fontan failure. Thirty-seven patients (77.1%) exhibited ventricular dysfunction (systolic dysfunction defined by ejection fraction ≤45%, n = 22, or diastolic dysfunction defined by systemic ventricular end-diastolic pressure (SVEDP) ≥12 mmHg, n = 15). Elevated indexed PVR (≥2.5 WU*m²) was only observed in 9 (18.8%) patients. Ejection fraction declined from 60% [IQR 55-65] to 47% [IQR 35-55] during follow-up (p < 0.001). Mean pulmonary artery pressure and SVEDP increased from 11 mmHg [IQR 9-15] to 15 mmHg [IQR 12-18] and from 7 mmHg [IQR 4-10] to 11 mmHg [IQR 8-15] (both p < 0.001), respectively, while indexed PVR did not change significantly (2.1 [IQR 1.1-2.4] vs. 1.7 [IQR 1.1-2.5] WU*m², p = 0.949). Fontan failure-associated mortality during follow-up was substantial (23/48; 48%).

CONCLUSIONS

Systolic and diastolic ventricular dysfunction are frequent features in late Fontan failure in adults, while increases in PVR were rarely observed. The intricate interplay between hemodynamic compromises in Fontan failure deserves further research to optimize treatment strategies and outcome.

Heart Rate Variability and Its Associations with Organ Complications in Adults after Fontan Operation

Reduction of heart rate variability (HRV) parameters may be a risk factor and precede the occurrence of arrhythmias or the development of heart failure and complications in people with postinfarct left ventricular dysfunction and after coronary artery bypass grafting. Data on this issue in adults after a Fontan operation (FO) are scarce. This study assessed the association between HRV, exercise capacity, and multiorgan complications in adults after FO. Data were obtained from 30 FO patients (mean age 24 ± 5.4 years) and 30 healthy controls matched for age and sex. HRV was investigated in all patients by clinical examination, laboratory tests, echocardiography, a cardiopulmonary exercise test, and 24-h electrocardiogram. The HRV parameters were reduced in the FO group. Reduced HRV parameters were associated with patients’ age at the time of FO, time since surgery, impaired exercise capacity, chronotropic incompetence parameters, and multiorgan complications. Univariate analysis showed that saturated O₂ at rest, percentage difference between adjacent NN intervals of >50 ms duration, and peak heart rate were associated with chronotropic index. Multivariable analysis revealed that all three variables were independent predictors of the chronotropic index. The results of this study suggest novel pathophysiological mechanisms that link HRV, physical performance, and organ damage in patients after FO.

Three-dimensional imaging of pulmonary arterial vasa vasorum using optical coherence tomography in patients after bidirectional Glenn and Fontan procedures

AIMS

We evaluated pulmonary arterial (PA) vasa vasorum (VV) in Fontan candidate patients with a novel three-dimensional (3D) imaging technique using optical coherence tomography (OCT).

METHODS AND RESULTS

This prospective study assessed the development of adventitial VV in the distal PA of 10 patients with bidirectional Glenn circulation (BDG group, 1.6 ± 0.3 years) and Fontan circulation (Fontan group, 3.3 ± 0.3 years), and in 20 children with normal PA haemodynamics and morphology (Control group, 1.5 ± 0.3 years). We assessed the PA VV with two-dimensional (2D) cross-sectional, multi-planar reconstruction (MPR), and volume rendering (VR) imaging. VV development was evaluated by the VV area/volume ratio, defined as the VV area/volume divided by the adventitial area/volume. Compared to the control group, the observed VV number and diameter on 3D images of MPR and VR were significantly higher, and curved and torturous-shaped VV were more frequently observed in the BDG and Fontan groups (P < 0.001, all). The median VV volume ratio was significantly greater in the BDG than in the control group (3.38% vs. 0.61%; P < 0.001). Although the VV volume ratio decreased significantly after the Fontan procedure (2.64%, P = 0.005 vs. BDG), the ratio remained higher than in the control group (P < 0.001 vs. control).

CONCLUSION

3D OCT imaging is a novel method that can be used to evaluate adventitial PA VV and may provide pathophysiological insight into the role of the PA VV in these patients.

Long-Term Outcomes After Fenestration Closure in High-Risk Fontan Candidates

The study aimed to assess the long-term outcomes after fenestration closure in patients at risk for Fontan failure. Of 119 patients who underwent Fontan operation between 1995 and 2004, fenestration was not created in 89 patients (NF group) and created in 30 patients with hypoplastic left heart syndrome, heterotaxy syndrome, high pulmonary arterial pressure, high systemic ventricular end-diastolic pressure, low ventricular ejection fraction, or atrioventricular valve regurgitation. All fenestrations were closed spontaneously or by catheter/surgical interventions, excepting two patients, and therefore, they were excluded. In fenestration group, patients with pre-Fontan mean pulmonary arterial pressure ≥ 15 mmHg or systemic atrioventricular valve regurgitation ≥ moderate were classified as high-risk Fontan candidates (F-HR group, n = 16), and the remaining patients were as standard-risk (F-SR group, n = 12). Protein-losing enteropathy-free survival rates did not differ among the three groups (p = 0.72). Serial follow-up catheter examinations after Fontan operation were completed in 69 patients in NF group and 11 patients in both F-SR and F-HR groups. Cardiac index and pulmonary vascular resistance significantly and similarly decreased over time in all groups, though the F-HR group showed lowest arterial oxygen saturation, lowest cardiac index, and highest pulmonary vascular resistance. The F-HR group also showed much veno-venous collaterals (p = 0.049), low peak oxygen consumption (p = 0.019), and low anaerobic threshold (p = 0.023) as compared to those in the F-SR group. In F-HR group, cyanosis remained after fenestration closure due to transformation from fenestration to veno-venous collaterals, which resulted in elevation of pulmonary vascular resistance, low cardiac index, and deterioration of exercise tolerance.

The pulmonary vascular bed in patients with functionally univentricular physiology and a Fontan circulation

Fontan palliation represents one of the most remarkable surgical advances in the management of individuals born with functionally univentricular physiology. The operation secures adult survival for all but a few with unfavourable anatomy and/or physiology. Inherent to the physiology is passive transpulmonary blood flow, which produces a vulnerability to adequate filling of the systemic ventricle at rest and during exertion. Similarly, the upstream effects of passive flow in the lungs are venous congestion and venous hypertension, especially marked during physical activity. The pulmonary vascular bed has emerged as a defining character on the stage of Fontan circulatory behaviour and clinical outcomes. Its pharmacologic regulation and anatomic rehabilitation therefore seem important strategic therapeutic targets. This review seeks to delineate the important aspects of pulmonary artery development and maturation in functionally univentricular physiology patients, pulmonary artery biology, pulmonary vascular reserve with exercise, and pulmonary artery morphologic and pharmacologic rehabilitation.

Long-term results of concomitant atrioventricular valve intervention and the Fontan operation

OBJECTIVES

The optimal timing for atrioventricular valve (AVV) repair in patients with a Fontan circulation remains controversial. Few studies have reported the long-term outcomes of AVV repair concomitant with a Fontan operation.

METHODS

From January 2006 to December 2018, a total of 89 patients who developed moderate or severe AVV regurgitation before a Fontan operation were divided into 2 groups: group 1, including 37 patients who did not undergo concomitant AVV repair; and group 2, including 52 patients who received AVV repair concomitant with a Fontan operation.

RESULTS

The mean age at the time of the Fontan operation was 6.74 years for group 1 and 8.96 years for group 2, respectively. Early death occurred in 3 patients [2 patients (5.4%) in group 2, patient 1 (1.9%) in group 1]. Freedom from long-term death, cardiac function reduction and protein-losing enteropathy were similar among the 2 groups. Common AVV function was apparently poorer than mitral valve function after repair [hazard ratio (HR) 3.83, 95% confidence interval (CI) 1.31-11.17; P = 0.014]. The occurrence of AVV valve failure in group 1 was lower than that in group 2 (HR 0.44, 95% CI 0.22-0.91; P = 0.026). AVV function became worse during the follow-up period than that at discharge in both groups (P = 0.03 in group 1 and P = 0.001 in group 2).

CONCLUSIONS

The long-term results of AVV repair concomitant with a Fontan operation are favourable.

Persisting and reoccurring cyanosis after Fontan operation is associated with increased late mortality

OBJECTIVES

The Fontan operation aims at reducing cyanosis and cardiac volume overload in patients with complex univentricular heart malformations. However, persisting or reoccurring cyanosis is frequently observed. We sought to systematically determine the prevalence and clinical consequences of persisting and secondary cyanosis after Fontan operation.

METHODS

A total of 331 Fontan patients, operated between 1984 and 2016 with a median postoperative follow-up of 7.9 (interquartile range 2.6-15.8) years, were studied retrospectively. Cyanosis was defined as transcutaneous oxygen saturation ≤93% at rest measured by pulse oximetry. Prevalence of cyanosis was analysed at 3 different time points (t1 = post-Fontan operation, t2 = post-Fontan cardiac catheterization, t3 = last follow-up) and the association of cyanosis with mortality was examined.

RESULTS

Prevalence of cyanosis was 50% at t1 and 39% at t3. Fenestration was patent in 71% and 33% of all cyanotic patients at t1 and t3, respectively. In patients with clinical indication for catheterization (t2; n = 178/331), prevalence of cyanosis was 72%. At t2, patent fenestration (33%), veno-venous collaterals (24%) or both (32%) were present. Thirty-six (11%) patients died during follow-up. In a time-varying multivariable Cox regression analysis, cyanosis was the strongest predictor for late mortality (P < 0.001, hazard ratio 12.2, 95% confidence interval 3.7-40.5).

CONCLUSIONS

Prevalence of cyanosis was considerable during long-term follow-up after Fontan operation and-as a surrogate parameter for unfavourable Fontan haemodynamics-is associated with increased late mortality. Accordingly, particular attention should be directed towards the persistence or reoccurrence of cyanosis during follow-up since it may indicate haemodynamic attrition and development of Fontan failure.

Hepatic Steatosis in Patients With Single Ventricle and a Fontan Circulation

Background

Hepatic steatosis, caused by nonalcoholic fatty liver disease, is a leading cause of chronic liver disease. The interplay between hepatic steatosis and the development of liver disease following the Fontan procedure is not well understood. This study examined the prevalence and associations of hepatic steatosis in patients with a Fontan circulation.

Methods and Results

This was a single‐center retrospective study of 95 patients with a Fontan circulation with liver magnetic resonance imaging performed between 2012 and 2019. The average age at magnetic resonance imaging was 21.5±8.5 years. The percent liver fat signal was determined using magnetic resonance chemical shift‐encoded proton density fat fraction imaging. Hepatic steatosis was defined as liver fat ≥5% and was present in 10.5% of the cohort. The presence of hepatic steatosis was associated with higher body mass index (29±4 versus 24±6 kg/m², P=0.006), a higher frequency of obesity (50% versus 12%, P=0.015), lower high‐density lipoprotein cholesterol (35±9 versus 43±14 mg/dL, P=0.050), and greater subcutaneous fat thickness (2.6±0.7 versus 1.8±1.0 cm, P=0.043). There was no association between hepatic steatosis and cardiovascular imaging or hemodynamic variables from cardiac catheterization.

Conclusions

Risk factors for hepatic steatosis in patients with Fontan circulation include obesity and dyslipidemia, similar to what is seen in the general population. Fontan hemodynamics were not associated with hepatic steatosis.