Thromboembolic Risk After Atriopulmonary, Lateral Tunnel, and Extracardiac Conduit Fontan Surgery

Comparison of definitive approaches for conotruncal defects following bidirectional Glenn procedure

BACKGROUND

Staged repair is common for complex conotruncal defects, often involving bidirectional Glenn (BDG) procedure. Following the cavopulmonary shunt, both Fontan completion and biventricular conversion (BiVC) serve as definitive approaches. The optimal strategy remains controversial.

METHODS

The baseline, perioperative and follow-up data were obtained for all paediatric patients with conotruncal defects who underwent BDG procedure as palliation in Fuwai Hospital from 2013 to 2022. Patients with single ventricle were excluded. The primary outcome was mortality. The secondary outcome was reintervention, including any cardiovascular surgeries and non-diagnostic catheterisations.

RESULTS

A total of 232 patients were included in the cohort, with 142 underwent Fontan (61.2%) and 90 underwent BiVC (38.8%). The median interstage period from BDG to the definitive procedure was 3.83 years (IQR: 2.72-5.42) in the overall cohort, 3.62 years (IQR: 2.57-5.15) in the Fontan group and 4.15 years (IQR: 3.05-6.13) in the BiVC group (p=0.03). The in-hospital outcomes favoured the Fontan group, including duration of cardiopulmonary bypass, aortic cross-clamp, mechanical ventilation and intensive care unit stay. Postoperative mortality was generally low and comparable, as was the reintervention rate (HR=1.42, 95% CI: 0.708 to 2.85, p=0.32). The left ventricular size was smaller at baseline and within the normal range at follow-up for both Fontan and BiVC groups; however, it was significantly larger with BiVC at follow-up.

CONCLUSION

In paediatric patients with conotruncal heart defects who underwent BDG procedure, BiVC is a feasible option, especially for patients with certain Fontan risk factors, and are not ideal candidates for successful Fontan completion.

Cardiovascular Outcomes in Fontan Patients With Right vs Left Univentricular Morphology: A Multicenter Study

Background

There is a paucity of data on long-term outcomes after Fontan palliation in patients with a dominant morphological univentricular right (uRV) vs left (uLV) ventricle.

Objectives

The purpose of this study was to compare the incidence of atrial arrhythmias, thromboembolic events, cardiac transplantation, and death following Fontan palliation in patients with uRV vs uLV.

Methods

The Alliance for Adult Research in Congenital Cardiology conducted a multicenter retrospective cohort study on patients with total cavopulmonary connection Fontan palliation across 12 centers in North America. All components of the composite outcome, that is, atrial arrhythmias, thromboembolic events, cardiac transplantation, and death, were reviewed and classified by a blinded adjudicating committee. Time-to-event analyses were performed that accounted for competing risks.

Results

A total of 384 patients were followed for 10.5 ± 5.9 years. The composite outcome occurred in 3.7 vs 1.7 cases per 100 person-years for uRV (N = 171) vs uLV (N = 213), respectively (P < 0.001). In multivariable analyses, uRV conferred a >2-fold higher risk of the composite outcome (HR: 2.17, 95% CI: 1.45-3.45, P < 0.001). In secondary analyses of components of the primary outcome, uRV was significantly associated with a greater risk of cardiac transplantation or death (HR: 9.09, 95% CI: 2.17-38.46, P < 0.001) and atrial arrhythmias (HR: 2.17, 95% CI: 1.20-4.00, P = 0.010) but not thromboembolic events (HR: 1.64, 95% CI: 0.86-3.16, P = 0.131).

Conclusions

Fontan patients with uRV vs uLV morphology have a higher incidence of adverse cardiovascular events, including atrial arrhythmia, cardiac transplantation, and all-cause mortality.

Decreased erythrocyte aggregation in Glenn and Fontan: univentricular circulation as a rheologic disease model

BACKGROUND

In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation.

METHODS

We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences.

RESULTS

Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation.

CONCLUSIONS

Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss.

IMPACT

Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.

Impact of Fontan Fenestration on Adverse Cardiovascular Outcomes: A Multicentre Study

BACKGROUND

Fenestrating a Fontan baffle has been associated with improved perioperative outcomes in patients with univentricular hearts. However, longer-term potential adverse effects remain debated. We sought to assess the impact of a fenestrated Fontan baffle on adverse cardiovascular events including all-cause mortality, cardiac transplantation, atrial arrhythmias, and thromboemboli.

METHODS

A multicentre North American retrospective cohort study was conducted on patients with total cavopulmonary connection Fontan baffle, with and without fenestration. All components of the composite outcome were independently adjudicated. Potential static and time-varying confounders were taken into consideration, along with competing risks.

RESULTS

A total of 407 patients were followed for 10.4 (7.1-14.4) years; 70.0% had fenestration of their Fontan baffle. The fenestration spontaneously closed or was deliberately sealed in 79.9% of patients a median of 2.0 years after Fontan completion. In multivariable analysis in which a persistent fenestration was modelled as a time-dependent variable, an open fenestration did not confer a higher risk of the composite outcome (hazard ratio, 1.18; 95% confidence interval, 0.71-1.97; P = 0.521). In secondary analyses, an open fenestration was not significantly associated with components of the primary outcome: that is, mortality or transplantation, atrial arrhythmias, or thromboemboli. However, sensitivity analyses to assess the possible range of error resulting from imprecise dates for spontaneous fenestration closures could not rule out significant associations between an open fenestration and atrial arrhythmias or thromboemboli.

CONCLUSIONS

In this multicentre study, no significant association was identified between an open fenestration in the Fontan baffle and major adverse cardiovascular events.

Long-term outcomes after heart transplantation in adult patients with univentricular versus biventricular congenital heart disease

OBJECTIVES

Heart transplantation (HT) is the only life-extending therapy in adults with congenital heart disease (CHD) and end-stage heart failure. HT is considered at high risk in complex CHD given the anatomical complexity and past medical history. Little is known about long-term outcomes after HT in these patients. We aimed to evaluate early and long-term outcomes after HT in adult patients with univentricular versus biventricular CHD.

METHODS

This multicentre retrospective cohort study included all adult CHD patients who underwent HT between 1988 and 2021 in 3 tertiary centres. Factors associated with early (<30 days) and conditional long-term survival were assessed in the entire cohort.

RESULTS

Over a mean follow-up of 10.1 ± 7.8 years, 149 patients were included, of whom 55 (36.9%) had univentricular CHD. Sixty-four patients died during follow-up including 47 deaths before discharge from hospital. In multivariable analysis, univentricular physiology and female recipient gender were independently associated with a higher risk of early mortality (odds ratio 2.99; 95% confidence interval [1.33-6.74] and odds ratio 2.76; 95% confidence interval [1.23-6.20], respectively). For patients who survived the early period, conditional long-term survival was excellent for both groups and was not different between 2 groups (P = 0.764).

CONCLUSIONS

Adult CHD patients have a high incidence of overall mortality due to a high rate of early mortality. Univentricular physiology was associated with a significant increased risk of early death compared to biventricular physiology. However, late mortality was excellent and no longer different between the 2 physiologies.

Atrial Arrhythmias in Adults with Fontan Palliation

Single ventricle physiology is a rare form of congenital heart disease and was, historically, a uniformly lethal condition. However, the atriopulmonary Fontan operation, and its successive iterations, the lateral tunnel and extracardiac conduit Fontan, became the fundamental approach to treating single ventricle heart disease. Over time, dysrhythmias are some of the most common complications with Fontan physiology, compounding morbidity and mortality. Atrial arrhythmias are prevalent in the Fontan population and occur in about 15-60% of patients with Fontan palliation, increasingly with age. Diagnosing atrial arrhythmias in patients with Fontan palliation may be challenging because of low voltage amplitudes arising from myopathic atrial tissue making it difficult to clearly assess atrial depolarization on surface electrocardiograms (ECG), vague symptoms not suggestive of tachyarrhythmia, or atrial arrhythmia with ventricular rates below 100 beats per minute. Intra-atrial reentrant tachycardia (IART) is the most common type of supraventricular tachycardia in adults with Fontan palliation. Acute management of atrial arrhythmias in patients with Fontan palliation involves prompt assessment of a patient's hemodynamic stability, anticoagulation and thrombosis risk, systemic ventricular function, and risk of sedation or anesthesia if needed. Long-term management of atrial arrhythmias is often multifactorial and may include long-term anti-arrhythmic therapy, permanent pacing, and ablation. The best approach for the management of atrial arrhythmias in adults with Fontan palliation is patient-specific and involves collaboration between congenital electrophysiologists, adult congenital cardiologists, and the patient.

Thromboembolic Complications in Adult Patients Following Fontan Procedure-A Multicenter Study

BACKGROUND

Morbidity and mortality following Fontan (FO) surgery are primarily thromboembolic in nature. However, follow-up data regarding thromboembolic complications (TECs) in adult patients after FO procedure are inconsistent. In this multicenter study, we investigated the incidence of TECs in FO patients.

METHODS

We studied 91 patients who underwent FO procedure. Clinical data, laboratory, and imaging investigations were collected prospectively during the scheduled medical appointments in 3 Adult Congenital Heart Disease Departments in Poland. TECs were recorded during a median follow-up of 31 months.

RESULTS

Four patients (4.4%) were lost to follow-up. The mean age of patients was 25.3 (±6.0) years at enrollment, and the mean time between FO operation and investigation was 22.1 (±5.1) years. A total of 21 out of 91 patients (23.1%) had a history of 24 TECs since an FO procedure, mainly pulmonary embolism (PE; n = 12, 13.2%), including 4 (33.3%) silent PE. The mean time since FO operation to the first TEC was 17.8 (±5.1) years. During follow-up, we documented 9 TECs in 7 (8.0%) patients, mainly PE (n = 5, 5.5%). Most patients with TEC had a left type of systemic ventricle (57.1%). Three patients (42.9%) were treated with aspirin, 3 (3.4%) with Vitamin K antagonists or novel oral anticoagulants, and 1 patient had no antithrombotic treatment at the time of TEC occurrence. Supraventricular tachyarrhythmias were present in 3 patients (42.9%).

CONCLUSIONS

This prospective study shows that TECs are common in FO patients, and a significant number of these events occur during adolescence and young adulthood. We also indicated how much TECs are underestimated in the growing adult FO population. The complexity of the problem requires more studies, especially to standardize the prevention of TECs in the whole FO population.

Hemostasis assessment in Fontan patients using the new thrombodynamics test

BACKGROUND

Thromboembolic events are a well-known risk for Fontan patients and often lead to morbidity and mortality in cyanotic patients and patients with a single ventricle. Coagulopathy and thrombophilia, in addition to disturbed Fontan blood flow and endothelial injury, are major contributors to thromboembolic complications. However, there is currently no consensus regarding the optimal medication to prevent or treat these events. Identification of coagulation disorders is therefore crucial for selecting appropriate management strategies and evaluating long-term outcomes in these patients.

CASE PRESENTATION

We present the case of a 35-year-old male who underwent the Fontan procedure with a total cavopulmonary modification during childhood due to tricuspid atresia. He was admitted with complaints of headaches and visual disturbances, but no clear cardiovascular cause was identified. Standard coagulation test parameters were normal, but the thrombodynamics test indicated severe hypercoagulation and spontaneous clot formation. Anticoagulation therapy was initiated, and a subsequent thrombodynamics assay showed normalization of the coagulation parameters. The patient remained asymptomatic during the six-month follow-up period.

CONCLUSIONS

The thrombodynamics test is a valuable tool for the diagnosis of coagulation disorders, as it can assess coagulation parameters and clot growth in vitro. This method can also aid in the optimization of antithrombotic therapy. The presented clinical case highlights the potential use of the thrombodynamics test in Fontan patients to diagnose coagulation disorders and improve long-term outcomes.

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.

Time in Therapeutic Range With Vitamin K Antagonists in Congenital Heart Disease: A Multicentre Study

BACKGROUND

Vitamin K antagonists (VKAs) are frequently prescribed to patients with congenital heart disease (CHD) for atrial arrhythmias or Fontan palliation, but there is a paucity of data regarding time spent in the therapeutic range (TTR). We sought to determine the TTR in patients with CHD and atrial arrhythmias or Fontan palliation prescribed VKAs and explore associations with thromboembolic and bleeding events.

METHODS

A multicentre North American cohort study was conducted on patients with CHD who received VKAs for sustained atrial arrhythmia or Fontan palliation. TTR was calculated using the Rosendaal linear interpolation method. Generalized estimating equations were used to explore factors associated with time outside the therapeutic range.

RESULTS

A total of 567 patients, aged 33 ± 17 years, 56% female, received VKAs for 11.5 ± 8.4 years for atrial arrhythmias (63.0%) or Fontan palliation (58.0%). CHD was simple, moderate, and complex in 10.8%, 20.3%, and 69.0%, respectively. Site investigators perceived good control over international normalized ratio (INR) levels in most patients (75.3%), with no or minor compliance or adherence issues (85.6%). The mean TTR was 41.9% (95% confidence interval [CI], 39.0%-44.8%). Forty-seven (8.3%) and 34 (6.0%) patients had thromboembolic and bleeding events, respectively. Thromboembolic events were associated with a higher proportion of time below the therapeutic range (31.3% vs 19.1%, P = 0.003) and bleeding complications with a higher proportion of time above the therapeutic range (32.5% vs 19.5%, P = 0.006).

CONCLUSIONS

Patients with CHD who receive VKAs spend < 42% of their time with INR levels in the therapeutic range, with repercussions regarding thromboembolic and bleeding complications.

Reproductive Issues in Patients With the Fontan Operation

Patients with the Fontan operation have a unique circulation, with a limited ability to increase cardiac output, and high central venous pressure. They may have diastolic and/or systolic ventricular dysfunction, arrhythmias, thromboembolic complications, or multiorgan dysfunction. All of these factors contribute to reproductive issues, including menstrual irregularities, infertility, recurrent miscarriage, and complications during pregnancy. Although atrial arrhythmias are the most common cardiac complications during pregnancy, patients can develop heart failure and thromboembolic events. Obstetric bleeding, including postpartum hemorrhage, is common. In addition to maternal complications, adverse fetal and neonatal events, such as prematurity and low birthweight, are very common. Counselling about these reproductive issues should begin early. For those who become pregnant, care should be provided by a multidisciplinary cardio-obstetric team familiar with the specific issues and needs of the Fontan population. In this review, we discuss infertility, contraception, and pregnancy in patients with the Fontan operation.

Coagulation and Anticoagulation in Fontan Patients

Patients with a Fontan circulation for single-ventricle physiology are at increased risk of developing thromboembolic events. Thromboembolic events can lead to failure of the Fontan circulation, chronic sequelae in case of stroke, and early mortality. Controversies exist regarding the substrates, risk factors, and optimal detection methods for thromboembolic events. Despite the major clinical implications, there is currently no consensus regarding the optimal antithrombotic therapy to prevent or treat thromboembolic events after the Fontan procedure. In this review we aimed to untangle the available literature regarding antithrombotic prophylaxis and treatment for pediatric and adult Fontan patients. A decision-tree algorithm for thromboprophylaxis in Fontan patients is proposed. Additionally, the current state of knowledge is reviewed with respect to the epidemiology, pathophysiology, and detection of thromboembolic events in Fontan patients, and important evidence gaps are highlighted.

Catheter ablation of atrial arrhythmias in patients post-Fontan

Atrial arrhythmias are highly prevalent in the aging Fontan population and contribute importantly to morbidity and mortality. Although the most common arrhythmia is scar-based intra-atrial re-entrant tachycardia, various other arrhythmias may occur including focal atrial tachycardia, atrioventricular node-dependent tachycardias, and atrial fibrillation. The type and prevalence of atrial arrhythmia is determined, in part, by the underlying congenital defect and variant of Fontan surgery. While the cumulative incidence of atrial tachyarrhythmias has decreased substantially from the atriopulmonary anastomosis to the more recent total cavopulmonary connection Fontan, the burden of atrial arrhythmias remains substantial. Management is often multi-faceted and can include anticoagulation, anti-arrhythmic drug therapy, pacing, and cardioversion. Catheter ablation plays a key role in arrhythmia control. Risks and benefits must be carefully weighed. Among the important considerations are the clinical burden of arrhythmia, ventricular function, hemodynamic stability in tachycardia, suspected arrhythmia mechanisms, risks associated with anaesthesia, venous access, approaches to reaching the pulmonary venous atrium, and accompanying co-morbidities. Careful review of surgical notes, electrocardiographic tracings, and advanced imaging is paramount, with particular attention to anatomic abnormalities such as venous obstructions and displaced conduction systems. Despite numerous challenges, ablation of atrial arrhythmias is effective in improving clinical status. Nevertheless, onset of new arrhythmias is common during long-term follow-up. Advanced technologies such as high-density mapping catheters and remote magnetic guided ablation carry the potential to further improve outcomes. Fontan patients with atrial arrhythmias should be referred to centers with dedicated expertise in congenital heart disease including catheter ablation, anaesthesia support, and advanced imaging.

Increased Risk for Thromboembolism After Fontan Surgery: Considerations for Thromboprophylaxis

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

Orale Antikoagulation bei Erwachsenen mit angeborenen Herzfehlern

Patienten mit angeborenen Herzfehlern weisen ein erhöhtes Risiko für das Auftreten thrombembolischer Ereignisse auf. Je nach zugrunde liegender Anatomie/operativer Korrektur ist dieses Risiko jedoch individuell sehr unterschiedlich und lässt sich weder hinsichtlich Embolierisiko noch hinsichtlich Blutungsrisiko durch die gängigen Risikoscores (z. B. CHA2DS2-VASc oder HAS-BLED) verlässlich abbilden. Neben der Frage der Indikationsstellung zur oralen Antikoagulation ist die Frage nach der Möglichkeit des Einsatzes neuer oraler Antikoagulanzien (NOAK) anstelle der Standardtherapie mit Vitamin-K-Antagonisten (VKA) eine immer drängendere, sofern kein mechanischer Klappenersatz und keine schwergradige Mitralstenose vorliegt. Bei atrialen Arrhythmien/Vorhofflimmern können nach momentaner Datenlage Patienten mit als „leicht“ klassifizierbaren Vitien mit NOAK behandelt werden, während Patienten mit mittelgradigen oder schweren/komplexen Herzfehlern eher mit VKA behandelt werden sollten.

Bleeding and thrombotic risk in pregnant women with Fontan physiology

BACKGROUND/OBJECTIVES

Pregnancy may potentiate the inherent hypercoagulability of the Fontan circulation, thereby amplifying adverse events. This study sought to evaluate thrombosis and bleeding risk in pregnant women with a Fontan.

METHODS

We performed a retrospective observational cohort study across 13 international centres and recorded data on thrombotic and bleeding events, antithrombotic therapies and pre-pregnancy thrombotic risk factors.

RESULTS

We analysed 84 women with Fontan physiology undergoing 108 pregnancies, average gestation 33±5 weeks. The most common antithrombotic therapy in pregnancy was aspirin (ASA, 47 pregnancies (43.5%)). Heparin (unfractionated (UFH) or low molecular weight (LMWH)) was prescribed in 32 pregnancies (30%) and vitamin K antagonist (VKA) in 10 pregnancies (9%). Three pregnancies were complicated by thrombotic events (2.8%). Thirty-eight pregnancies (35%) were complicated by bleeding, of which 5 (13%) were severe. Most bleeds were obstetric, occurring antepartum (45%) and postpartum (42%). The use of therapeutic heparin (OR 15.6, 95% CI 1.88 to 129, p=0.006), VKA (OR 11.7, 95% CI 1.06 to 130, p=0.032) or any combination of anticoagulation medication (OR 13.0, 95% CI 1.13 to 150, p=0.032) were significantly associated with bleeding events, while ASA (OR 5.41, 95% CI 0.73 to 40.4, p=0.067) and prophylactic heparin were not (OR 4.68, 95% CI 0.488 to 44.9, p=0.096).

CONCLUSIONS

Current antithrombotic strategies appear effective at attenuating thrombotic risk in pregnant women with a Fontan. However, this comes with high (>30%) bleeding risk, of which 13% are life threatening. Achieving haemostatic balance is challenging in pregnant women with a Fontan, necessitating individualised risk-adjusted counselling and therapeutic approaches that are monitored during the course of pregnancy.

Hemodynamic performance of tissue-engineered vascular grafts in Fontan patients

In the field of congenital heart surgery, tissue-engineered vascular grafts (TEVGs) are a promising alternative to traditionally used synthetic grafts. Our group has pioneered the use of TEVGs as a conduit between the inferior vena cava and the pulmonary arteries in the Fontan operation. The natural history of graft remodeling and its effect on hemodynamic performance has not been well characterized. In this study, we provide a detailed analysis of the first U.S. clinical trial evaluating TEVGs in the treatment of congenital heart disease. We show two distinct phases of graft remodeling: an early phase distinguished by rapid changes in graft geometry and a second phase of sustained growth and decreased graft stiffness. Using clinically informed and patient-specific computational fluid dynamics (CFD) simulations, we demonstrate how changes to TEVG geometry, thickness, and stiffness affect patient hemodynamics. We show that metrics of patient hemodynamics remain within normal ranges despite clinically observed levels of graft narrowing. These insights strengthen the continued clinical evaluation of this technology while supporting recent indications that reversible graft narrowing can be well tolerated, thus suggesting caution before intervening clinically.

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.

Thrombosis Prevention and Anticoagulation Management in the Pediatric Patient with Congenital Heart Disease

Thrombosis is one of the most frequent complications affecting children with congenital heart disease (CHD). Palliative and reparative cardiac surgeries are some of the main players contributing to the thrombosis risk in this patient population. Additional risk factors related to the CHD itself (e.g., cardiac dysfunction, arrhythmias, and polycythemia in cyanotic cardiac disorders) can contribute to thrombogenicity alone or combined with other factors. Thrombotic complications have been recognized as a significant cause of morbidity and mortality in this patient population. Here, we provide an overview of the pathophysiology and risk factors for thrombosis as well as the indications for and use of different anticoagulation, antiplatelet, and thrombolytic agents. In addition, we describe some of most common thrombotic complications and their management in the pediatric CHD population.

Atrial pacing in Fontan patients: The effect of transvenous lead on clot burden

BACKGROUND

Transvenous permanent pacemaker (PPM) implantation is an available option for Fontan patients with sinus node dysfunction. However, the thrombogenic potential of leads within the Fontan baffle is unknown.

OBJECTIVE

The purpose of this study was to compare the clot burden in Fontan patients with a transvenous atrial PPM to those without a PPM and those with an epicardial PPM.

METHODS

This was a retrospective cohort study of all transvenous PPM implantations in Fontan patients followed at our institution (2000-2018). We performed frequency matching on Fontan type and age group. Primary outcome was identification of intracardiac clot, pulmonary embolus, or embolic stroke.

RESULTS

Of 1920 Fontan patients, 58 patients (median age 23 years; interquartile range [25th-75th percentiles] 14-33) at the time of transvenous PPM implantation and 174 matched subjects formed our cohort. The type of Fontan performed in case subjects was right atrium-pulmonary artery or right atrium-right ventricle conduit (54%), lateral tunnel (43%), and extracardiac (3%). The cumulative incidence of clot was highest in patients with transvenous PPM, followed by patients with epicardial PPM and no PPM (1.2 vs 0.87 vs 0.67 per 100 person-years of follow-up, respectively). In multivariable analysis, anticoagulation and/or antiplatelet therapy were protective against clot and resulted in reduction of clot risk by 3-fold (incidence rate ratio 0.33; 95% confidence interval 0.21-0.53; P <.001).

CONCLUSION

In a large cohort of Fontan patients matched for age and Fontan type, patients with transvenous PPM had a higher but not statistically significant incidence of clot compared to those with no PPM and epicardial PPM. Patients treated with warfarin/aspirin had lower clot risk.

Ventricular Assist Device Therapy in the Fontan Circulation

The number of Fontan patients with circulatory failure and systolic dysfunction is growing rapidly. The last decade has demonstrated that ventricular assist device (VAD) is an effective therapy in properly selected patients. Herein, we discuss the current approach to patient selection, implantation, and patient management.

Recurrent sustained atrial arrhythmias and thromboembolism in Fontan patients with total cavopulmonary connection

Background

Total cavopulmonary connection (TCPC) is associated with a lower risk of incident atrial arrhythmias as compared to atriopulmonary Fontan, but the risk of recurrent atrial arrhythmias is unknown in this population. The purpose of this study was to determine the incidence and risk factors for recurrent atrial arrhythmias and thromboembolic complications in patients with TCPC.

Methods

This is a retrospective multicenter study conducted by the Alliance for Adult Research in Congenital Cardiology (AARCC), 2000-2018. The inclusion criteria were TCPC patients (age > 15 years) with prior history of atrial arrhythmia.

Results

A total of 103 patients (age 26 ± 7 years; male 58 [56%]) met inclusion criteria. The mean age at initial arrhythmia diagnosis was 13 ± 5 years, and atrial arrhythmias were classified as atrial flutter/tachycardia in 85 (83%) and atrial fibrillation in 18 (17%). The median duration of follow-up from the first episode of atrial arrhythmia was 14.9 (12.1-17.3) years, and during this period 64 (62%) patients had recurrent atrial arrhythmias (atrial flutter/tachycardia 51 [80%] and atrial fibrillation 13 [20%]) with annual incidence of 4.4%. Older age was a risk factor for arrhythmia recurrence while the use of a class III anti-arrhythmic drug was associated with a lower risk of recurrent arrhythmias. The incidence of thromboembolic complication was 0.6% per year, and the cumulative incidence was 4% and 7% at 5 and 10 years respectively from the time of first atrial arrhythmia diagnosis. There were no identifiable risk factors for thromboembolic complications in this cohort.

Conclusions

Although TCPC provides superior flow dynamics and lower risk of incident atrial arrhythmias, there is a significant risk of recurrent arrhythmias among TCPC patients with a prior history of atrial arrhythmias. These patients may require more intensive arrhythmia surveillance as compared to other TCPC patients.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pre-Fontan Cardiac Catheterization Data as a Predictor of Prolonged Hospital Stay and Post-Discharge Adverse Outcomes Following the Fontan Procedure: A Single-Center Study

Despite improved outcomes following modifications to the Fontan technique, significant morbidity and mortality persist. We sought to determine if abnormal pre-Fontan catheterization hemodynamic data will predict postoperative prolonged hospital stay (PHLOS) and adverse post-discharge outcomes. This is a retrospective study of patients who underwent the Fontan procedure at Children's Hospital of New Orleans from 2008 to 2018. PHLOS was defined as ≥ 14 and ≥ 21 days to discharge post Fontan. We defined post-discharge adverse outcomes as thromboembolic phenomena requiring anticoagulation therapy, protein-losing enteropathy, plastic bronchitis, transplantation, persistent chylous effusion requiring fenestration creation, or death. Statistical analysis was performed using student t test, Chi-square test, and multivariable logistic regression analysis using IBM SPSS version 22. Ninety-seven patients underwent extracardiac Fontan. Forty-one patients (42.3%) experienced hospitalization ≥ 14 days, 31 patients (32%) experienced hospitalization ≥ 21 days, and 14 patients (14.4%) experienced adverse post-discharge outcome. Elevated end-diastolic pressure (EDP) ≥ 10 mmHg (p = 0.005, OR 4.2, CI 1.5-11.4) was independently associated with ≥ 14 days of hospitalization, while a CI < 4 L/minute/meters² combined with one abnormal catheterization variable was associated with PHLOS and post-discharge adverse outcomes (p = 0.03, OR 2.8, CI 1.1-7.3 and p = 0.043, OR 6.42, OR 1.1-38.9, respectively). The absence of fenestration was also associated with post-discharge adverse outcomes (p = 0.007, OR 5.8, CI1.6-20.7). Elevated EDP may be associated with PHLOS, while CI < 4 L/minute/meters² combined with abnormal catheterization hemodynamics may be associated with PHLOS and adverse post-discharge outcomes, while absence of fenestration may be associated with post-discharge adverse events.

Evaluating the Longevity of the Fontan Pathway

Children born with single ventricle physiology who undergo Fontan palliation face a diverse set of long-term complications. However, patient follow-up has in large part been limited to single institutional experiences without uniform application of diagnostic modalities to screen for relevant outcomes. Additionally, the use of different graft materials and variable surgical technique as part of the Fontan procedure has further complicated the evaluation of single ventricle patients. The purpose of this review is to define the changes in the Fontan pathway specific to the graft material used and its relationship to patient outcomes. As a means of introduction, we briefly review the historical evolution of the Fontan procedure with a focus on the intent behind design changes and incorporation of different biomaterials. We further delineate changes to the Fontan pathway which include the development of stenosis, differential growth, thrombosis, and calcification. Ultimately, the recognition of the changes noted within the Fontan pathway need to be assessed relative to their impact on patient hemodynamics, functional capacity, and Fontan-associated comorbidities.

Adults with Congenital Heart Disease and Arrhythmia Management

Arrhythmia management in adult congenital heart disease (ACHD) encompasses a wide range of problems from bradyarrhythmia to tachyarrhythmia, sudden death, and heart failure-related electrical dyssynchrony. Major advances in the understanding of the pathophysiology and treatments of these problems over the past decade have resulted in improved therapeutic strategies and outcomes. This article attempts to define these problems and review contemporary management for the patient with ACHD presenting with cardiac arrhythmia.

Tricuspid atresia: Where are we now?

Tricuspid atresia (TA) is a complex congenital heart disease that presents with cyanosis in the neonatal period. It is invariably fatal if left untreated and requires multiple stages of palliation. Early recognition and timely surgical intervention are therefore pivotal in the management of these infants. This literature review considers the pathophysiology, presentation, investigations, and classification of TA. Moreover, it discusses the evidence upon which the latest medical and surgical treatments are based, as well as numerous recent case reports. Further work is needed to elucidate the etiology of TA, clarify the role of pharmacotherapy, and optimize the surgical management that these patients receive.