Role and Applications of Experimental Animal Models of Fontan Circulation.

Over the last four decades, the Fontan operation has been the treatment of choice for children born with complex congenital heart diseases and a single-ventricle physiology. However, therapeutic options remain limited and despite ongoing improvements in initial surgical repair, patients still experience a multiplicity of cardiovascular complications. The causes for cardiovascular failure are multifactorial and include systemic ventricular dysfunction, pulmonary vascular resistance, atrioventricular valve regurgitation, arrhythmia, development of collaterals, protein-losing enteropathy, hepatic dysfunction, and plastic bronchitis, among others. The mechanisms leading to these late complications remain to be fully elucidated. Experimental animal models have been developed as preclinical steps that enable a better understanding of the underlying pathophysiology. They furthermore play a key role in the evaluation of the efficacy and safety of new medical devices prior to their use in human clinical studies. However, these experimental models have several limitations. In this review, we aim to provide an overview of the evolution and progress of the various types of experimental animal models used in the Fontan procedure published to date in the literature. A special focus is placed on experimental studies performed on animal models of the Fontan procedure with or without mechanical circulatory support as well as a description of their impact in the evolution of the Fontan design. We also highlight the contribution of animal models to our understanding of the pathophysiology and assess forthcoming developments that may improve the contribution of animal models for the testing of new therapeutic solutions.

The Prevalence of Scoliosis after Fontan Circulation Surgery Followed-Up to Adolescence.

Introduction: The advancement of surgical techniques and perioperative management for congenital heart disease (CHD) has increased life expectancy. The surgical creation of the Fontan circulation maintains pulmonary blood flow without relying on an effective pump from the abnormal heart, relying on peripheral vascular resistance to maintain effective flow through the lungs. Unfortunately, this delicate mechanism is compromised when scoliosis restricts ventilation, leading to Fontan failure and a poor prognosis for life. This report describes the prevalence of scoliosis with Fontan completion surgery and the role of screening and surgical correction. Methods: Ninety-six consecutive Japanese patients undergoing Fontan completion surgery for CHD between 2000 and 2017 were identified in our institutional records. The inclusion criterion was at least 7 years of follow-up after Fontan completion surgery, while the exclusion criteria were congenital, syndromic, and neuromuscular scoliosis. Radiographic and clinical parameters, including cardio-thoracic ratio (CTR) for cardiomegaly and cyanosis saturation, were compared between with and without scoliosis. Results: There were 23 and 40 patients in the scoliosis and no scoliosis groups, respectively. The mean age at the final follow-up was 18.5 and 16.7 years in the scoliosis and no scoliosis groups, respectively (p=0.02). Mean CTR was 43.7% and 39.4% in the scoliosis and no scoliosis groups (p=0.016), and the mean saturation in room air at the final follow-up was 88.8% and 93.2%, respectively (p=0.036). There were no significant differences to clarify the risk factors with multivariate logistic regression analysis. Conclusions: The prevalence of scoliosis with Fontan completion surgery was 36.5%. Screening for scoliosis is important for children with Fontan circulation surgery as part of their routine follow-up at least until they reach adolescence.Evidence Level: 4.

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.

Corazón univentricular sin cirugía de Fontan: el tipo de paliación importa / Univentricular hearts not undergoing Fontan: the type of palliation matters

Introducción y objetivos: La información sobre pacientes con fisiología univentricular (FU) y flujo pulmonar restrictivo no sometidos a cirugía de Fontan es escasa. El objetivo de este estudio es comparar la supervivencia y los eventos cardiovasculares en estos pacientes según el tipo de paliación.MétodosLos datos de pacientes con FU se obtuvieron de las bases de datos de 7 centros con unidades de cardiopatías congénitas del adulto. Se excluyó a los pacientes que completaron la circulación de Fontan o desarrollaron un síndrome de Eisenmenger. Se crearon 3 grupos según la fuente de flujo pulmonar: G1, flujo anterógrado pulmonar restrictivo; G2, shunt cavopulmonar, y G3, shunt aortopulmonar±shunt cavopulmonar. El objetivo principal fue la muerte.ResultadosSe identificó a 120 pacientes. La media de edad en la primera visita fue 32,2 años. El seguimiento medio fue de 7,1 años. Se asignó a 55 pacientes (45,8%) al G1, 30 (25%) al G2 y 35 (29,2%) al G3. Los pacientes del G3 tenían peores función renal, clase funcional y fracción de eyección en la primera visita y mostraron una disminución más marcada de la fracción de eyección durante el seguimiento, especialmente en comparación con el G1. Veinticuatro pacientes (20%) fallecieron, 38 (31,7%) ingresaron por insuficiencia cardiaca y 21 (17,5%) presentaron aleteo/fibrilación auricular durante el seguimiento. Estos eventos fueron más frecuentes en el G3 y al compararlos con los del G1 se encontraron diferencias significativas en muerte (HR=2,9; IC95%, 1,14-7,37; p=0,026) y aleteo/fibrilación auricular (HR=2,9; IC95%, 1,11-7,68; p=0,037).ConclusionesEl tipo de paliación de los pacientes con FU y flujo pulmonar restrictivo no sometidos a cirugía de Fontan identifica distintos perfiles. Los pacientes paliados con derivaciones aortopulmonares presentan un peor pronóstico, con más morbilidad y mortalidad. (AU)

Introduction and objectives: There is scarce information on patients with single ventricle physiology (SVP) and restricted pulmonary flow not undergoing Fontan circulation. This study aimed to compare survival and cardiovascular events in these patients according to the type of palliation.MethodsSVP patient data were obtained from the databases of the adult congenital heart disease units of 7 centers. Patients completing Fontan circulation or developing Eisenmenger syndrome were excluded. Three groups were created according to the source of pulmonary flow: G1 (restrictive pulmonary forward flow), G2 (cavopulmonary shunt), and G3 (aortopulmonary shunts±cavopulmonary shunt). The primary endpoint was death.ResultsWe identified 120 patients. Mean age at the first visit was 32.2 years. Mean follow-up was 7.1 years. Fifty-five patients (45.8%) were assigned to G1, 30 (25%) to G2, and 35 (29.2%) to G3. Patients in G3 had worse renal function, functional class, and ejection fraction at the first visit and a more marked ejection fraction decline during follow-up, especially when compared with G1. Twenty-four patients (20%) died, 38 (31.7%) were admitted for heart failure, and 21 (17.5%) had atrial flutter/fibrillation during follow-up. These events were more frequent in G3 and significant differences were found compared with G1 in terms of death (HR, 2.9; 95%CI, 1.14-7.37; P=.026) and atrial flutter/fibrillation (HR, 2.9; 95%CI, 1.11-7.68; P=.037).ConclusionsThe type of palliation in patients with SVP and restricted pulmonary flow not undergoing Fontan palliation identifies distinct profiles. Patients palliated with aortopulmonary shunts have an overall worse prognosis with higher morbidity and mortality. (AU)

Ideal chest compression site for cardiopulmonary resuscitation in fontan circulation patients with dextrocardia.

BACKGROUND: We aimed to identify the ideal chest compression site for cardiopulmonary resuscitation (CPR) in patients with a single ventricle with dextrocardia corrected by Fontan surgery. METHODS: The most recent stored chest computed tomography images of all patients with a single ventricle who underwent Fontan surgery were retrospectively analysed. We reported that the ideal chest compression site is the largest part of the compressed single ventricle. To identify the ideal chest compression site, we measured the distance from the midline of the sternum to the point of the maximum sagittal area of the single ventricle as a deviation and calculated the area fraction of the compressed structures. RESULTS: 58 patients (67.2% male) were analysed. The mean right deviation from the midline of the sternum to the ideal compression site was similar to the mean sternum width (32.85 ± 15.61 vs. 31.05 ± 6.75 mm). When chest compression was performed at the ideal site, the area fraction of the single ventricle significantly increased by 7%, which was greater than that of conventional compression (0.15 ± 0.10 vs. 0.22 ± 0.11, P < 0.05). CONCLUSIONS: When performing CPR on a patient with Fontan circulation with dextrocardia, right-sided chest compression may be better than the conventional location.

Biomarkers of fibrosis and portal hypertension in Fontan-associated liver disease in children and adults.

BACKGROUND: Fontan-associated liver disease (FALD) refers to structural and functional changes of the liver caused by the physiology of the Fontan palliation. Currently, liver biopsy is the gold standard to assess liver fibrosis of FALD. AIM: Investigate biomarkers correlating with severity of liver biopsy fibrosis in FALD. METHODS: A retrospective study of post-Fontan patients ≥ 10 years of age who underwent liver biopsy was conducted. Advanced liver disease (ALD) was defined as bridging fibrosis and/or cirrhosis on liver biopsy. AST-to-platelet ratio index (APRI), Fibrosis-4 (FIB-4) and Liver Stiffness Measurement (LSM) from FibroScan were used as non-invasive fibrosis scores. RESULTS: Sixty-six patients (26/47; 55.3% adults and 13/19 children; 68.4%) had ALD on biopsy. ALD was associated with lower platelet count (151 vs. 198 K/uL, p = 0.003), higher APRI (0.64 vs. 0.32, p = 0.01), higher FIB-4 (0.64 vs. 0.32, p = 0.02). Liver fibrosis score correlated with APRI (0.34, p = 0.02) and FIB-4 (0.47, p = 0.001) in adults. LSM had a high sensitivity at 81.3% with 45.5% specificity at a cut-off 18.5 kPa. CONCLUSIONS: APRI and FIB-4 had modest discrimination to identify adults with advanced liver disease, but not children, indicating that these values may be followed as a marker of FALD progression in older patients.

Anaesthetic management of a child with Fontan heart undergoing laparoscopic cholecystectomy: A case report.

The Fontan procedure is a staged palliative surgery performed in children with congenital univentricular heart defects. These individuals are predisposed to a variety of issues due to their altered physiology. Through this article, we would like to describe the evaluation and anaesthetic management of a 14-year-old boy with Fontan circulation who underwent an uneventful laparoscopic cholecystectomy. The key to successful management was a multidisciplinary approach throughout the perioperative period as these patients pose a unique set of problems.

Univentricular hearts not undergoing Fontan: the type of palliation matters.

INTRODUCTION AND OBJECTIVES: There is scarce information on patients with single ventricle physiology (SVP) and restricted pulmonary flow not undergoing Fontan circulation. This study aimed to compare survival and cardiovascular events in these patients according to the type of palliation. METHODS: SVP patient data were obtained from the databases of the adult congenital heart disease units of 7 centers. Patients completing Fontan circulation or developing Eisenmenger syndrome were excluded. Three groups were created according to the source of pulmonary flow: G1 (restrictive pulmonary forward flow), G2 (cavopulmonary shunt), and G3 (aortopulmonary shunts±cavopulmonary shunt). The primary endpoint was death. RESULTS: We identified 120 patients. Mean age at the first visit was 32.2 years. Mean follow-up was 7.1 years. Fifty-five patients (45.8%) were assigned to G1, 30 (25%) to G2, and 35 (29.2%) to G3. Patients in G3 had worse renal function, functional class, and ejection fraction at the first visit and a more marked ejection fraction decline during follow-up, especially when compared with G1. Twenty-four patients (20%) died, 38 (31.7%) were admitted for heart failure, and 21 (17.5%) had atrial flutter/fibrillation during follow-up. These events were more frequent in G3 and significant differences were found compared with G1 in terms of death (HR, 2.9; 95%CI, 1.14-7.37; P=.026) and atrial flutter/fibrillation (HR, 2.9; 95%CI, 1.11-7.68; P=.037). CONCLUSIONS: The type of palliation in patients with SVP and restricted pulmonary flow not undergoing Fontan palliation identifies distinct profiles. Patients palliated with aortopulmonary shunts have an overall worse prognosis with higher morbidity and mortality.

Detection of hepatocellular carcinoma during Fontan-associated liver disease follow-up: a report of three cases.

We herein demonstrate three patients diagnosed with early hepatocellular carcinoma (HCC) during follow-up for Fontan-associated liver disease (FALD). Case 1: Twenty-one years after undergoing the Fontan procedure, a 26-year-old female was diagnosed with FALD. At the initial consultation, her serum alpha-fetoprotein (AFP) levels were markedly elevated, and dynamic enhanced computed tomography (CT) revealed HCC measuring 40 mm in diameter. She underwent partial hepatectomy. Ten months later, she underwent conventional transcatheter arterial chemoembolization (cTACE) for recurrent HCC near the resected hepatic stump as a curative treatment. Case 2: Twenty-one years after undergoing the Fontan procedure, a 25-year-old male was diagnosed with FALD and underwent HCC surveillance every 6 months. Thirteen months after the initial consultation, dynamic enhanced CT revealed HCC measuring 10 mm in diameter. He received cTACE as a curative treatment. Case 3. Twenty-eight years after undergoing the Fontan procedure, a 37-year-old male was diagnosed with FALD and underwent HCC surveillance every 3 months. Fourteen months later, abdominal ultrasonography (US) revealed HCC measuring 13 mm in diameter. He received radiofrequency ablation. These cases showed that HCC surveillance using abdominal US and AFP measurements in patients with FALD enables the detection of HCC and increases the chance of a cure.

Dysbiosis of gut microbiota in patients with protein-losing enteropathy after the Fontan procedure.

BACKGROUND: There is a lack of predictive biomarkers for the onset or activity of protein-losing enteropathy (PLE), a Fontan procedure-associated complication. Here, we aimed to identify the gut microbiota composition of patients with active PLE and investigate its relationship with PLE activity. METHODS: This multicenter case-control study involved patients who developed PLE (n = 16) after the Fontan procedure and those who did not (non-PLE; n = 20). Patients with PLE who maintained a serum albumin level of ≥3 g/dL for >1 year were included in the remissive-stage-PLE group (n = 9) and those who did not maintain this level were included in the active-PLE group (n = 7). 16S rRNA gene sequencing analysis of fecal samples was performed using QIIME2 pipeline. Alpha (Shannon and Faith's phylogenetic diversity indices) and beta diversity was assessed using principal coordinate analysis based on unweighted UniFrac distances. RESULTS: Shannon and Faith's phylogenetic diversity indices were lower in the active-PLE group than in the remissive-stage- (q = 0.028 and 0.025, respectively) and non-PLE (q = 0.028 and 0.017, respectively) groups. Analysis of beta diversity revealed a difference in the microbiota composition between the active-PLE and the other two groups. Linear discriminant effect size analysis demonstrated differences in the relative abundance of Bifidobacterium and Granulicatella spp., and Ruminococcus torques between patients with active- and those with remissive-stage-PLE. CONCLUSIONS: Gut microbiota dysbiosis was observed in patients with active PLE. Changes in the bacterial composition of the gut microbiota and decreased diversity may be associated with the severity of PLE.

Peak oxygen consumption by smartwatches compared with cardiopulmonary exercise test in complex congenital heart disease.

OBJECTIVE: To evaluate for correlation between exercise capacity as assessed by peak oxygen consumption (pVO2) measurement during a cardiopulmonary exercise test (CPET) and smartwatches reporting this parameter in patients with adult congenital heart disease (ACHD) complex lesions. METHODS: A prospective study that included patients with ACHD either a Fontan circulation or a right ventricle supporting the systemic circulation who underwent two separate CPETs at least 1 year apart. Generalised estimating equations linear regression was performed to identify factors associated with correlation between smartwatch and CPET-derived pVO2. RESULTS: 48 patients (71% with a Fontan circulation, 42% females, mean age 33±9 years) underwent two CPETs between May 2018 and May 2022 with echocardiograms performed within 6 months of each CPET. Apple Watch was the predominant smartwatch used (79%). Smartwatch and CPET measured peak heart rate (Pearson correlation=0.932, 95% CI (0.899, 0.954)) and pVO2 (0.8627, 95% CI (0.8007, 0.9064) and 0.8634, 95% CI (0.7676, 0.9215) in the first and second CPET, respectively) correlated well, with smartwatch-measured pVO2 values measuring higher by a mean of 3.146 mL/kg/min (95% CI (2.559, 3.732)). Changes in pVO2 between the first and the second CPET also correlated well (Pearson correlation=0.9165, 95% CI (0.8549, 0.9525)), indicating that for every 1 mL/(min kg) change in CPET-measured pVO2, there was a corresponding 0.896 mL/(min kg) change in the smartwatch-measured pVO2. CONCLUSION: Both absolute values and changes over time in pVO2 as measured by smartwatches and CPETs correlate well in patients with complex ACHD.

Impact of Optimal Fenestration Size on Outcomes of High-Risk Fontan Patients.

BACKGROUND: We aimed to analyze mid-term outcomes of the fenestrated Fontan procedure, focusing on the fenestration size. METHODS: We retrospectively reviewed the outcomes of the fenestrated Fontan procedure. Among 165 patients who underwent the Fontan procedure from 2011 to 2021, fenestration was created in 27 patients with the highest risks, including those with hypoplastic left heart syndrome, hypoplastic pulmonary arteries, heterotaxy syndrome with high pulmonary vascular resistance, and pulmonary arterial pressure >15 mm Hg. The patients underwent the procedure at a median age of three years (body weight, 11.4 kg; body surface area, 0.54 m2). Fenestration sizes were 3.5 to 5 mm. RESULTS: Spontaneous fenestration closure occurred within one year postoperatively in nine patients. Among them, three experienced Fontan failure, necessitating refenestration. Although fenestration size did not differ, the size corrected by body surface area at the time of surgery was smaller in patients with fenestration closure (6.4 mm/m2 vs 8.3 mm/m2, P < .05). Patients with a fenestration <7 mm/m2 were more likely to have fenestration closure within one year postoperatively, and those with a fenestration >9 mm/m2 were more likely to have severe desaturation and require home oxygen therapy following discharge. CONCLUSIONS: Spontaneous fenestration closure affected the frequency of Fontan complications. A very small fenestration size corrected by body surface area was a significant risk factor for spontaneous closure. Conversely, a very large fenestration size corrected by body surface area resulted in severe desaturation. The optimal fenestration size to prevent early spontaneous closure and severe desaturation is approximately 8 mm/m2.

The Effect of Udenafil on Heart Rate and Blood Pressure in Adolescents With the Fontan Circulation.

The Fontan Udenafil Exercise Longitudinal (FUEL) trial showed that treatment with udenafil was associated with improved exercise performance at the ventilatory anaerobic threshold in children with Fontan physiology. However, it is not known how the initiation of phosphodiesterase 5 inhibitor therapy affects heart rate and blood pressure in this population. These data may help inform patient selection and monitoring after the initiation of udenafil therapy. The purpose of this study is to evaluate the effects of udenafil on vital signs in the cohort of patients enrolled in the FUEL trial. This international, multicenter, randomized, double-blind, placebo-controlled trial of udenafil included adolescents with single ventricle congenital heart disease who had undergone Fontan palliation. Changes in vital signs (heart rate [HR], systolic [SBP] and diastolic blood pressure [DBP]) were compared both to subject baseline and between the treatment and the placebo groups. Additional exploratory analyses were performed to evaluate changes in vital signs for prespecified subpopulations believed to be most sensitive to udenafil initiation. Baseline characteristics were similar between the treatment and placebo cohorts (n = 200 for each). The groups demonstrated a decrease in HR, SBP, and DBP 2 hours after drug/placebo administration, except SBP in the placebo group. There was an increase in SBP from baseline to after 6-min walk test in the treatment and placebo groups, and the treatment group showed an increase in HR (87.4 ± 15.0 to 93.1 ± 19.4 beats/min, p <0.01) after exercise. When comparing changes from baseline to the 26-week study visit, small decreases in both SBP (-1.9 ± 12.3 mm Hg, p = 0.03) and DBP (-3.0 ± 9.6 mm Hg, p <0.01) were seen in the treatment group. There were no clinically significant differences between treatment and placebo group in change in HR or blood pressure in the youngest age quartile, lightest weight quartile, or those on afterload-reducing agents. In conclusion, initiation of treatment with udenafil in patients with Fontan circulation was not associated with clinically significant changes in vital signs, implying that for patients similar to those enrolled in the FUEL trial, udenafil can be started without the requirement for additional monitoring after initial administration.

[Percutaneous management of severe hemoptysis in a patient after fontan surgery]. / Manejo percutáneo de hemoptisis severa en paciente posoperada de cirugía de fontan.

We present the case of a patient with a history of single ventricle, tricuspid atresia, double outlet of the left ventricle and hypoplasia of the pulmonary artery ring. The patient was treated with Glenn's surgery at the age of 7 and at age 16, the patient received fenestrated extracardiac Fontan surgery. After 1 month of Fontan surgery she presented severe hemoptysis without adequate response to medical management. Percutaneous closure of aortopulmonary fistulas with coils was performed, with favorable evolution, without presenting recurrences of hemoptysis.

Persistent Patent Vertical Vein After Repair of Total Anomalous Pulmonary Venous Connection (TAPVR): A Rare Cause of Hypoxemia Post-Fontan Procedure.

Vertical vein (VV) ligation during total anomalous pulmonary venous return (TAPVR) repair is controversial. While some surgeons prefer ligation of the VV to prevent adverse sequelae of shunting across it and to promote flow through the newly created anastomosis, others leave it to serve as a "pop off valve" to the left heart structures, which are believed to be hypoplastic and noncompliant, presumably contributing to a more favorable post-operative outcome. We report two patients post-Fontan procedure, who underwent cardiac catheterization to explore the etiology of hypoxia and were found to have a persistent VV responsible for right to left shunting. Both patients underwent closure of the VV with improvement in the cyanosis and clinical course. These cases provide evidence supporting surgical ligation of the VV at the time of TAPVR repair, especially in patients with single ventricle.

O2 pulse slope correlates with stroke volume during exercise in patients with a Fontan circulation.

BACKGROUND: Peak oxygen pulse (O2pulse=oxygen consumption/heart rate) is calculated by the product of stroke volume (SV) and oxygen extraction. It has been shown to be reduced in patients with a Fontan circulation. However, in the Fontan population, it may be a poor marker of SV. We propose that the slope of the O2 pulse curve may be more reflective of SV during exercise. METHODS: We analysed cardiopulmonary exercise test data in 22 subjects with a Fontan circulation (cohort A) and examined the association between peak SV during exercise (aortic flow measured on exercise cardiac MRI), and O2 pulse parameters (absolute O2 pulse and O2 pulse slopes up to anaerobic threshold (AT) and peak exercise). In a separate Fontan cohort (cohort B, n=131), associations between clinical characteristics and O2 pulse kinetics were examined. RESULTS: In cohort A, peak aortic flow was moderately and significantly associated with O2pulseslopePEAK (r=0.47, p=0.02). However, neither absolute O2pulseAT nor O2pulsePEAK was significantly associated with peak aortic flow. In cohort B, O2pulseslopePEAK and O2pulseslopeAT were not significantly associated with clinical parameters, apart from a weak association with forced vital capacity. CONCLUSION: The slope of the O2 pulse curve to peak exercise may be more reflective of peak SV in the Fontan population than a single peak O2 pulse value.

Risk Factors for Thromboembolic and Bleeding Events in Patients After the Fontan Operation (Insights from the National Database of Health Insurance Claims of Japan).

Risk stratification of thromboembolic events (TEs) and bleeding events is important for the appropriate selection of thromboprophylaxis in patients after the Fontan operation. Therefore, we clarified the risk factors for TEs and bleeding events in patients after the Fontan operation using the National Database of Health Insurance Claims and Specific Health Checkups of Japan. We conducted a retrospective cohort study including 2,515 patients who underwent the Fontan operation between June 2011 and September 2019. The end points were TEs and bleeding events within 1 year of the Fontan operation analysis. We analyzed the risk factors for these end points using a multivariate analysis. In total, 1,903 patients were included in the analysis. The median age at the time of the Fontan operation was 3 (1 to 22) years, and 1,067 patients (56%) were male. The incidence rates of TEs and bleeding events were 12% and 11%, respectively. Age (odds ratio [OR] 1.1 per 1 year older, p <0.05) was an independent risk factor for TEs. Thromboprophylaxis with aspirin after the Fontan operation significantly reduced TEs (OR 0.3, p <0.05). A history of postoperative hemorrhage (OR 1.5, p <0.05) and the use of a potassium channel blocker (OR 2.1, p <0.05) were independent risk factors for bleeding events. In conclusion, aspirin was found to reduce the risk of TEs within 1 year of the Fontan operation. The results of this study will be useful in selecting effective and safe thromboprophylaxis in patients after the Fontan operation.

Outcomes After Hybrid Palliation for Infants With Critical Left Heart Obstruction.

BACKGROUND: Hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) is an initial management strategy for infants with critical left heart obstruction and serves as palliation until subsequent operations are pursued. OBJECTIVES: This study sought to determine patient characteristics and factors associated with subsequent outcomes for infants who underwent hybrid palliation. METHODS: From 2005 to 2019, 214 of 1,236 prospectively enrolled infants within the Congenital Heart Surgeons' Society's critical left heart obstruction cohort underwent hybrid palliation across 24 institutions. Multivariable hazard modeling with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan procedure, transplantation, or death. RESULTS: Preoperative comorbidities (eg, prematurity, low birth weight, genetic syndrome) were identified in 70% of infants (150 of 214). Median follow-up was 7 years, ranging up to 17 years. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had biventricular repair, 36% had Fontan procedure, 12% had transplantation, 35% died without surgical endpoints, and 8% were alive without an endpoint. Factors associated with transplantation were absence of ductal stent, older age, absent interatrial communication, smaller aortic root size, larger tricuspid valve area z-score, and larger left ventricular volume. Factors associated with death were low birth weight, concomitant genetic syndrome, cardiopulmonary bypass use during hybrid palliation, moderate to severe tricuspid valve regurgitation, and smaller ascending aortic size. CONCLUSIONS: Mortality remains high after hybrid palliation for infants with critical left heart obstruction. Nonetheless, hybrid palliation may facilitate biventricular repair for some infants and for others may serve as stabilization for intended functional univentricular palliation or primary transplantation.