Fontan Patients Research Articles

Life and Death: A Multicenter Study Evaluating Cardiologists' Approach to Difficult Conversations with Fontan Patients and Families.

Outpatient cardiologists provide longitudinal care for Fontan patients. As these patients age, they face mounting morbidities, necessitating challenging conversations about prognosis and goals of care. We created a novel survey to evaluate cardiologists' attitudes surrounding risk counseling for patients/caregivers. Cardiologists were recruited during concomitant outpatient enrollment of individuals with Fontan operation > age 10. Physician demographic data, expectations of timing in discussing adverse event risk, and perceived barriers were collected. Barriers were analyzed using a thematic approach. 40 cardiologists (9 institutions) responded regarding 155 patients (mean age 21.2years, SD 7.7). Physicians were mostly male (58%) with mean practice of 21years post-fellowship (SD 12). Most felt the time was right to have a conversation with patient (55%) and family (62%), and majority thought patient (53%) and family (75%) were ready for such a conversation. Most had previously discussed prognosis with patient (72%) and family (75%). Providers were inclined to discuss risk with caregivers earlier (mean patient age 9years, SD 11) than patients (mean patient age 17years, SD 6.4). Nevertheless, 42% of physicians perceived significant barriers and provided 58 narrative comments categorized into 4 major themes: (1) Patient-related (53.4%), including cognitive limitations and mental health; (2) Provider-related (16.4%), including lack of familiarity, preservation of happiness, and discomfort; (3) Family related (12.3%), including protection/denial and psychosocial stressors; (4) Other (26%), including social barriers. Experienced cardiologists are willing to have difficult conversations; nearly half reported largely patient-related barriers. Facilitating these conversations is critical for the adolescent/young adult with Fontan physiology.

Innominate Vein Turndown Procedure as Another Option for Lymphatic Abnormalities in Fontan Patients.

Innominate Vein Turndown Procedure as Another Option for Lymphatic Abnormalities in Fontan Patients.

Effect of liver abnormalities on mortality in Fontan patients: a systematic review and meta-analysis

BackgroundFontan-associated liver disease (FALD) is one of the most common complications following Fontan procedure, but the impact of FALD on survival outcomes remains controversial. The aim of this systematic review and meta-analysis was to examine and quantify the influence of liver disease on the survival of Fontan patients.MethodsThe Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines were followed, and relevant human studies published from inception up to 12 August 2022 were searched. Stata (version 17.0) was applied to perform the meta-analysis, using random effects (Mantel-Haenszel) models. The I2 statistic was used to assess the heterogeneity. Subgroup analysis and meta-regression were employed to explore the potential sources of heterogeneity and sensitivity analysis was performed to determine the potential influence of each study on the overall pooled results.ResultsA total of 312 records were initially identified and 8 studies involving 2,466 patients were selected for inclusion. Results revealed a significant association between the severity of liver disease following Fontan procedure and mortality, which was confirmed by sensitivity analysis and subgroup analysis assessing post-HT mortality. Meta-regression showed that diagnostic methods for liver disease may be a source of heterogeneity. After removal of the FALD patients identified by international classification of disease codes, heterogeneity was markedly reduced, and the positive association between all-cause mortality and the severity of liver disease became significant.ConclusionsThis meta-analysis showed the severity of liver disease following the Fontan procedure has a significant association with mortality. Lifelong follow-up is necessary and imaging examinations are recommended for routine surveillance of liver disease. Among patients with failing Fontan and advanced liver disease, combined heart-liver transplantation may provide additional survival benefits.

Augmented Biphasic Breathing Using Sniff and an Oral Positive Expiratory Pressure Device (Sniff-PEP) in Fontan Patients.

The use of an oral positive expiratory pressure device (oPEP) with sniff breathing (Sniff-PEP) mimics biphasic ventilation. Biphasic ventilation increases pulmonary blood flow and cardiac output in Fontan patients. The aim of this study was to assess the effect of Sniff-PEP on Fontan flow velocities. A single-center, pilot, prospective study was carried out in 15 subjects with Fontan circulation enrolled to use the oPEP device for 1month. Subjects were instructed on Sniff-PEP and to use the device for 10-15min 3-4 times a day. Measurements of flow velocity and cardiac output were measured via echocardiogram and quality of life assessments were performed at baseline and 4-6weeks later. The mean age at enrollment was 19.9 ± 8.7years (age range of 10-37years). 7 patients (47%) had dominant left ventricle and 8 (53%) had an open fenestration. There was a statistically significant increase in flow velocities in the hepatic vein from 27.5 ± 7.6 to 35.1 ± 11.3cm/s (p = 0.003), left pulmonary artery from 51.6 ± 16.6 to 57.6 ± 21.1cm/s (p = 0.01), and right pulmonary artery from 43.1 ± 14.2 to 45.8 ± 17.2cm/s (p = 0.04). With chronic use, the mean fenestration gradient slightly decreased from 4.5 ± 1.6 to 4.1 ± 1.9mmHg but the difference was not statistically significant (p = 0.14). oPEP device therapy increased flow velocity in several areas in the Fontan circulation with acute use. Further studies are needed to assess the effects long term.Clinical Trial Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT03251742.

Patient Reported Outcome Measures in Adults with Fontan Circulatory Failure.

Background: Patient reported outcomes (PROs) are important measures in acquired heart disease but have not been well defined in Adult Congenital Heart Disease (ACHD). Our aim was to explore the discriminatory capacity of PRO survey tools in Fontan circulatory failure (FCF). Methods: Consecutive adults were enrolled from our ambulatory clinics. Inclusion criteria were age ≥18 years, a Fontan circulation or a hemodynamically insignificant shunt lesion, and sufficient cognitive/language abilities to complete PROs. A comprehensive package of PRO measures, designed to assess perceived health-related quality of life (HRQOL) was administered (including the Kansas City Cardiomyopathy Questionnaire [KCCQ-12], EuroQol-5-dimension [EQ5D], Short Form Health Status Survey [SF-12], self-reported New York Heart Association [NYHA] Functional Class, and Specific Activity Scale [SAS]). Results: We compared 54 Fontan patients (35 ± 10 years) to 25 simple shunt lesion patients (34 ± 11 years). The KCCQ-12 score was lower in Fontan versus shunt lesion patients (87 [IQR 79, 95] versus 100 [IQR 97, 100], p-value < 0.001). The FCF subgroup was associated with lower KCCQ-12 scores as compared with the non-FCF subgroup (82 [IQR 56, 89] versus 93 [IQR 81, 98], p-value = 0.002). Although the KCCQ-12 had the best discriminatory capacity for determination of FCF of all PRO tools studied (c-statistic 0.75 [CI 0.62, 0.88]), superior FCF discrimination was achieved when the KCCQ-12 was combined with all PRO tools (c-statistic 0.82 [CI 0.71, 0.93]). Conclusions: The KCCQ-12 questionnaire demonstrated good discriminatory capacity for the identification of FCF, which was further improved through the addition of complementary PRO tools. Further research will establish the value of PRO tools to guide management strategies in ACHD.

Quality of Life and Well-Being in Adults With Fontan Physiology: Findings From the Australian and New Zealand Fontan Registry Quality of Life Study.

To characterize global and health-related quality of life (QOL) among adults with Fontan physiology enrolled in the Australian and New Zealand Fontan Registry (ANZFR), and identify sociodemographic, clinical, psychological, and relational factors associated with outcomes. Using a cross-sectional survey design, 66 adults with Fontan physiology (58% women; mean age, 29.6±7.7 years; range, 18-50 years) completed validated self-report measures. Health-related QOL was assessed using the Pediatric Quality of Life Inventory, and global QOL was assessed using a visual analog scale (0-10). Participants reported lower total health-related QOL (P<0.001), as well as lower physical (P<0.001) and social (P=0.002) functioning compared with normative data. Median global QOL was 7.0 (interquartile range: 5.0-8.0) and most participants (71%) rated their QOL ≥6. For health-related QOL, age, sex, university education, and length of hospital stay in the past 12 months explained 27% of the variance in scores, while general psychological stress, medical traumatic stress, communication problems, and access to emotional support explained a further 44% of variance (final model: 71% of variance explained). For global QOL, sociodemographic and clinical factors explained 20% of the variance in scores, while psychological stress and sense of coherence explained a further 24% (final model: 44% of variance explained). Adults with Fontan physiology reported lower overall health-related QOL compared with community-based norms. Variance in QOL outcomes were predominantly attributable to psychological and relational factors. Tailored screening and assessment to identify Fontan patients at greatest risk of lower QOL, and a proactive approach to supportive care, are needed.

Application of Principal Component Analysis to Heterogenous Fontan Registry Data Identifies Independent Contributing Factors to Decline.

Single ventricle heart disease is a severe and life-threatening illness, and improvements in clinical outcomes of those with Fontan circulation have not yet yielded acceptable survival over the past two decades. Patients are at risk of developing a diverse variety of Fontan-associated comorbidities that ultimately requires heart transplant. Our observational cohort study goal was to determine if principal component analysis (PCA) applied to data collected from a substantial Fontan cohort can predict functional decline (N=140). Heterogeneous data broadly consisting of measures of cardiac and vascular function, exercise (VO2max), lymphatic biomarkers, and blood biomarkers were collected over 11 years at a single site; in that time, 16 events occurred that are considered here in a composite outcome measure. After standardization and PCA, principal components (PCs) representing >5% of total variance were thematically labeled based on their constituents and tested for association with the composite outcome. Our main findings suggest that the 6th PC (PC6), representing 7.1% percent of the total variance in the set, is greatly influenced by blood serum biomarkers and superior vena cava flow, is a superior measure of proportional hazard compared to EF, and displayed the greatest accuracy for classifying Fontan patients as determined by AUC. In bivariate hazard analysis, we found that models combining systolic function (EF or PC5) and lymphatic dysfunction (PC6) were most predictive, with the former having the greatest AIC, and the latter having the highest c-statistic. Our findings support our hypothesis that a multifactorial model must be considered to improve prognosis in the Fontan population.

Quantifying and visualizing abdominal hemodynamics in patients with Fontan circulation by 4D phase-contrast flow magnetic resonance imaging at 1.5 T

BackgroundLiver fibrosis has been recognized as a long-term morbidity associated with Fontan circulation (Fontan-associated liver disease, FALD). The pathophysiology of FALD is not completely understood and abnormal flow dynamics may be associated with this condition. Liver hemodynamics can be quantitatively evaluated with four-dimensional phase-contrast flow magnetic resonance imaging (4D PC flow MRI). The study aimed to evaluate suitability of liver 4D PC flow MRI in Fontan patients and relate flow measurements to normal values and FALD severity. Patients and methodsTwenty-two Fontan patients were examined by 4D PC flow MRI at 1.5 Tesla to assess mesenteric, portal, splenic, and hepatic venous blood flow. Severity of FALD was graded based on routine screening, including abdominal ultrasound and laboratory tests. ResultsMedian age was 18.5 (interquartile range, IQR 15.5–20.2) years. FALD was graded as “none or mild” in 16 and as “moderate to severe” in six cases. Ten patients presented at least one feature of portal hypertension (ascites, splenomegaly, or thrombocytopenia). For the entire cohort, blood flow in the superior mesenteric, splenic, and portal vein was lower than reported in the literature. No significant differences were observed in relation to FALD severity. Features of portal hypertension were associated with a higher splenic vein blood flow (0.34 ± 0.17 vs. 0.20 ± 0.07 l/min, p = 0.046). Splenic vein blood flow was negatively correlated to platelet count (r = −0.590, p = 0.005). Conclusions4D PC flow MRI appears suitable to assess liver hemodynamics in Fontan patients and integration into clinical follow-up might help to improve our understanding of FALD.

Investigation of a chronic single-stage sheep Fontan model

ObjectivesOur goal was to conduct a hemodynamic analysis of a novel animal model of Fontan physiology. Poor late-term outcomes in Fontan patients are believed to arise from Fontan-induced hemodynamics, but the mechanisms remain poorly understood. Recent advances in surgical experimentation have resulted in the development of a chronic sheep model of Fontan physiology; however, detailed analysis of this model is lacking. MethodsWe created a single-stage Fontan model in juvenile sheep with normal biventricular circulation. The superior vena cava was anastomosed to the main pulmonary artery, and the inferior vena cava was connected to the main pulmonary artery using an expanded polytetrafluoroethylene conduit. Longitudinal hemodynamics, including catheterization and magnetic resonance imaging were evaluated. ResultsFour out of 12 animals survived, with the longest surviving animal living 3 years after single-stage Fontan. We showed a significant era effect regarding survival (1 out of 8 and subsequently 3 out of 4 animals surviving beyond 2 months) attributed in large part to the procedural learning curve. Key characteristics of Fontan hemodynamics, namely systemic venous hypertension and low normal cardiac output, were observed. However, recapitulation of passive human Fontan hemodynamics is affected by volume loading of the right ventricle given an anatomic difference in sheep azygous venous anatomy draining to the coronary sinus. ConclusionsA significant learning curve exists to ensure long-term survival and future surgical modifications, including banding of the main pulmonary artery and ligation of the azygous to coronary sinus connection are promising strategies to improve the fidelity of model hemodynamics.

Creation of a secondary fenestration in the inferior vena cava stump with Occlutech Atrial Flow Regulator implantation in a Fontan patient.

Creation of a secondary fenestration in the inferior vena cava stump with Occlutech Atrial Flow Regulator implantation in a Fontan patient.

Liver fibrosis detected by diffusion-weighted magnetic resonance imaging and its functional correlates in Fontan patients.

The evaluation of Fontan-associated liver disease is often challenging. Diffusion-weighted magnetic resonance imaging can detect hepatic fibrosis from capillary perfusion and diffusion abnormalities from extracellular matrix accumulation. This study investigated its role in the evaluation of liver disease in Fontan patients and explored possible diagnostic methods for early detection of advanced liver fibrosis. Stable adult Fontan patients who could safely be examined with magnetic resonance imaging were enrolled, and blood biomarkers, transient elastography were also examined. Forty-six patients received diffusion-weighted imaging; and 58.7% were diagnosed with advanced liver fibrosis (severe liver fibrosis, 37.0%, and cirrhosis 21.7%). Two parameters of hepatic dysfunction, platelet counts (Spearman's ρ: -0.456, P = 0.001) and cholesterol levels (Spearman's ρ: -0.383, P = 0.009), decreased with increasing severity of fibrosis. Using transient elastography, a cut-off value of 14.2 kPa predicted the presence of advanced liver fibrosis, but with a low positive predictive value. When we included platelet count, cholesterol, post-Fontan years and transient elastography values as a composite, the capability of predicting advanced liver fibrosis was the most satisfactory (C statistic 0.817 ± 0.071, P < 0.001). A cut-off value of 5.0 revealed a sensitivity of 78% and a specificity of 82%. In Fontan patients, diffusion-weighted imaging was helpful in detecting liver fibrosis that was correlated with hepatic dysfunction. A simple score was proposed for long-term surveillance and early detection of advanced liver disease in adult Fontan patients. For adult Fontan patients with a calculated score > 5.0, we may consider timely diffusion-weight imaging and early management for liver complications.

Vitamin D deficiency and secondary hyperparathyroidism in adult Fontan patients

BackgroundThe prevalence of vitamin D deficiency and secondary hyperparathyroidism (sHPT) in adult Fontan patients remains unstudied, and the role of vitamin D and parathyroid hormone (PTH) levels in assessing heart and circulatory failure in these patients is unclear. MethodsWe compared vitamin D deficiency and sHPT prevalence in adult Fontan patients (n = 35; mean age 33 ± 7.5 years) to adults with mild congenital heart disease (ACHD, n = 14). We analyzed associations between laboratory measurements, patient characteristics, and clinical events. FindingsVitamin D deficiency was highly prevalent in both Fontan patients and ACHD controls (76.5 % vs. 71.4 %, p = 0.726). sHPT was exclusively present in Fontan patients (31.4 %). PTH levels correlated with NYHA class (r = 0.412), O2 saturation (r = −0.39), systemic ventricular function (r = 0.465), and NT-proBNP levels (r = 0.742). 25-hydroxyvitamin D showed an inverse correlation with NYHA class and systemic ventricular function (both r ≤ −0.38). Fontan patients with sHPT had a higher incidence of prior hospitalization for worsening heart failure and atrial arrhythmias compared to Fontan patients without HPT or ACHD controls. (Hospitalization: Fontan with HPT vs. Fontan without HPT: OR 5.46 [95 % CI 1.25–23.86], p = 0.021; arrhythmia: Fontan with HPT vs. Fontan without HPT: OR 1.96 [95 % CI 1.13–3.4], p = 0.035; ACHD: OR 11.45 [95 % CI 1.7–77.28], p=<0.001). PTH showed significant correlation with inflammatory markers, particularly with GDF-15 (r = 0.8). ConclusionOur study is the first to demonstrate a high prevalence of vitamin D deficiency and sHPT in adult Fontan patients. As PTH strongly correlates with heart failure severity, it seems to be a promising biomarker in Fontan patients.

Iron deficiency in patients with a Fontan circulation and its impact on exercise capacity

BackgroundIron deficiency (ID) has been reported in patients with congenital heart disease. There is, however, a scarcity of data on its prevalence in patients with a Fontan circulation. The aim...

Accuracy of elastography versus biopsy in assessing severity of liver fibrosis in young Fontan patients.

We performed a single-centre retrospective study comparing the accuracy of non-invasive elastography with liver biopsy in accurate assessment of Fontan-associated liver disease. Fontan patients who underwent combined assessment with a percutaneous liver biopsy and non-invasive elastography between January 2015 and December 2023 at our Children's hospital were included. Liver biopsies were classified using the Congestive Hepatic Fibrosis Score as early Fontan-associated liver disease (scores 1, 2) and advanced Fontan-associated liver disease (score 3/bridging fibrosis and score 4/cirrhosis). Elastography values were categorised as advanced Fontan-associated liver disease for liver elasticity >2.1 m/s by ultrasound and liver stiffness >5 KPa on magnetic resonance elastography. We included 130 patients (116 children, 89%, mean age at biopsy: 14.6 years ± 3.6) who underwent liver biopsy at a mean duration of 11.1 years (±0.3) following Fontan surgery. Advanced Fontan-associated liver disease was noted in 41 (31.5%) patients with 13 (10%) showing frank cirrhosis. Pre-biopsy ultrasound showed advanced liver fibrosis in 18/125 (14%), with low sensitivity (23%), high specificity (90%), and low accuracy (68%, k = 0.1) in diagnosing advanced Fontan-associated liver disease. Similarly, pre-biopsy magnetic resonance elastography showed advanced fibrosis in 23/86 (27%) of patients, with low sensitivity (30%), fair specificity (75%), and low accuracy (63%, k = 0.1). Interestingly, advanced Fontan-associated liver disease was missed by ultrasound in 29% and by magnetic resonance elastography in 25% of patients. Advanced Fontan-associated liver disease was associated with lower platelet count (p = 0.02) and higher Gamma-glutamyl Transferase levels (p = 0.02). Advanced hepatic fibrosis is common among paediatric Fontan patients. Non-invasive elastography may overestimate and underestimate the degree of liver fibrosis, and therefore, liver biopsy may be required for confirming disease severity.

Ventricular Morphology and Outcomes in Fontan Circulation without Hypoplastic Left Heart Syndrome: A Single-Center's Experience.

The impact of dominant ventricular morphology on Fontan patient outcomes remain controversial. This study evaluates long-term results of right ventricle (RV) dominance versus left ventricle (LV) dominance in Fontan circulation without hypoplastic left heart syndrome (HLHS). We retrospectively examined 323 Fontan operations from our center. To minimize pre- and intra-Fontan heterogeneity, 42 dominant RV patients were matched with 42 dominant LV patients using propensity score matching, allowing for a comparative analysis of outcomes between groups. The mean follow-up was 8.0 4.6 years for matched RV dominant and 6.5 4.7 years for matched LV dominant group (p 0.05), showing no significant difference. The cumulative incidence of moderate or greater atrioventricular valve regurgitation was also comparable between the two groups (p 0.05). Similarly, 10-year freedom from death or transplantation following the Fontan operation was 84% 7% in the matched dominant RV group, similar to 81% 7% in the matched dominant LV group (p 0.05). The 10-year freedom from Fontan failure was 78% 8% in the matched dominant RV group, also similar to 75% 8% in the matched dominant LV group (p 0.05). Multivariate analysis did not identify RV dominance as a risk factor for Fontan failure (p 0.05). In the pre- and intra-Fontan context, RV dominance demonstrated similar and comparable long-term outcomes compared to LV dominance in non-HLHS Fontan circulation.

Heart Transplantation Following Fontan Failure: Long-Term Survival Analysis.

Objectives: Fontan circulation presents significant challenges for patients with congenital heart disease, often necessitating heart transplantation (HTX) due to deteriorating functionality across multiple organ systems. However, the impact of prior Fontan palliation on HTX outcomes remains poorly understood, with early mortality rates suggesting a heightened risk. The aim of our study is to evaluate the long-term results after heart transplantation in patients with univentricular congenital heart disease previously palliated with Fontan circulation. Methods: A retrospective analysis was conducted on patients who underwent HTX for congenital heart disease. Patients were categorized into two groups based on the pre-HTX circulation pathway: the Failing Fontan Group (FFG) and the Biventricular Congenital Group (BCG). Data were collected from patients between 1987 and 2018. Early and late outcomes, including survival rates, were assessed and critically analyzed. Results: Of the 66 patients, 29 (43%) had a failing Fontan palliation (FFG), and 37 had biventricular congenital diseases (BCG) before heart transplantation. Early mortality (30-day) was not statistically different between the two group. The overall survival rate was 82.6 ± 13.9% at 1 year, 79.0 ± 14.9% at 5 years, 67.2 ± 17.6% at 10 years and 63.2 ± 18.2 ± at 15 years for the FFG, and 86.1 ±11.4% at 1 year, 79.5 ± 13.7% at 5 years, 75.7 ± 14.9% at 10 years, 75.7 ± 14.9% at 15 years for the BCG, with no statistically significant difference (Mantel Cox p value: 0.69, 0.89, 0.52 and 0.39, respectively). Regarding Cox-regression analysis, the long-term survival rate was not affected either by previous Fontan surgery or by the era of heart transplantation (before vs. after the year 2000). Conclusions: Although heart transplantation after Fontan palliation showed a higher risk in the early post-operative period, the medium- and long-term survival rates are comparable with biventricular circulation patients. Despite the failing Fontan patients being a challenging set of candidates for transplantation, it is a reasonable option in their treatment.

Altered Serum Proteins Suggest Inflammation, Fibrogenesis and Angiogenesis in Adult Patients with a Fontan Circulation.

Previous omics research in patients with complex congenital heart disease and single-ventricle circulation (irrespective of the stage of palliative repair) revealed alterations in cardiac and systemic metabolism, inter alia abnormalities in energy metabolism, and inflammation, oxidative stress or endothelial dysfunction. We employed an affinity-proteomics approach focused on cell surface markers, cytokines, and chemokines in the serum of 20 adult Fontan patients with a good functioning systemic left ventricle, and we 20 matched controls to reveal any specific processes on a cellular level. Analysis of 349 proteins revealed 4 altered protein levels related to chronic inflammation, with elevated levels of syndecan-1 and glycophorin-A, as well as decreased levels of leukemia inhibitory factor and nerve growth factor-ß in Fontan patients compared to controls. All in all, this means that Fontan circulation carries specific physiological and metabolic instabilities, including chronic inflammation, oxidative stress imbalance, and consequently, possible damage to cell structure and alterations in translational pathways. A combination of proteomics-based biomarkers and the traditional biomarkers (uric acid, γGT, and cholesterol) performed best in classification (patient vs. control). A metabolism- and signaling-based approach may be helpful for a better understanding of Fontan (patho-)physiology. Syndecan-1, glycophorin-A, leukemia inhibitory factor, and nerve growth factor-ß, especially in combination with uric acid, γGT, and cholesterol, might be interesting candidate parameters to complement traditional diagnostic imaging tools and the determination of traditional biomarkers, yielding a better understanding of the development of comorbidities in Fontan patients, and they may play a future role in the identification of targets to mitigate inflammation and comorbidities in Fontan patients.

Adverse Effect of Bundle Branch Block on Exercise Performance in Patients with Fontan Physiology: From the Pediatric Heart Network Fontan Public Data Set.

Patients with Fontan physiology have reduced exercise performance compared to their peers as well as a higher incidence of bundle branch block (BBB). This study aims to investigate the association between BBB and exercise performance in the Fontan population through a retrospective review of the Pediatric Heart Network Fontan study public use dataset. "Low Performers" were defined as ≤ 25th percentile (for Fontan patients) for each exercise parameter at anaerobic threshold (AT) for gender and age and "Normal Performers" were all other patients. A total of 303 patients with Fontan physiology who underwent exercise testing reached AT and had complete data for BBB. BBB occurred more frequently in Low Performers for VO2 [OR (95% CI): 2.6 (1.4, 4.8)] and Work [OR (95% CI): 2.7 (1.4, 5.1)], suggesting that BBB in the Fontan population is associated with reduced exercise performance. This data adds to the existing clinical evidence of the adverse effects of conduction abnormalities on single ventricle cardiac output and adds support for consideration of cardiac resynchronization and multi-site ventricular pacing in this patient population.

B-17 | Feasibility of Transfemoral Venous Liver Biopsy with Intracardiac Echo Guidance in Fontan Patients

B-17 | Feasibility of Transfemoral Venous Liver Biopsy with Intracardiac Echo Guidance in Fontan Patients

Bilateral bidirectional cavopulmonary connection: a review of surgical techniques and clinical implications.

The presence of bilateral superior caval veins (bSCVs) could negatively influence the outcome of Fontan patients. In the setting of a bilateral bidirectional Glenn, the selective blood flow to the ipsilateral long with consequent flow stagnation in the connecting portion could lead to poor growth of the central portion of the pulmonary artery, potentially affecting the eligibility for Fontan completion and being associated with a higher incidence of thrombotic complications. Alternative surgical techniques have been described to perform a bidirectional cavopulmonary anastomosis in the presence of bSCVs aiming to achieve a balanced growth of the pulmonary bifurcation. The short-term results of these techniques such as the V- or Y-shape seem to be excellent; however, some anatomical settings could affect the feasibility of these techniques. The so-called "unifocalization" creates a configuration comparable to a "normal" bidirectional Glenn and could be a feasible alternative. However, the long-term results of this technique are not published yet. The positive effect of additional pulsatile pulmonary flow on pulmonary artery growth should be considered in case of bilateral bidirectional Glenn, despite the higher incidence of postoperative complications reported and the difficult calibration of the amount of additional flow. The role of computational fluid dynamic to simulate the surgical strategy in single ventricle patients is promising and could be worthwhile in the setting of bSCVs. In fact, the surgical techniques of bilateral bidirectional Glenn could be simulated testing their feasibility and allowing to identify the more favorable hemodynamic pattern, patient specific. This review article highlights the critical issues related to the presence of bSCVs in univentricular physiology, analyzing pros and cons of the different surgical techniques. Besides reviewing the literature, this manuscript focuses on the role of computational fluid simulation in identifying the most favorable surgical technique with an individualized approach, which could potentially improve the clinical outcome.