Single Ventricle Patients Research Articles

Risk Factors and Outcomes of Children with Congenital Heart Disease on Extracorporeal Membrane Oxygenation-A Ten-Year Single-Center Report.

For children born with congenital heart defects (CHDs), extracorporeal life support may be necessary. This retrospective single-center study aimed to investigate the outcomes of children with CHDs on extracorporeal membrane oxygenation (ECMO), focusing on various risk factors. Among the 88 patients, 36 (41%) had a single-ventricle heart defect, while 52 (59%) had a biventricular defect. In total, 25 (28%) survived, with 7 (8%) in the first group and 18 (20%) in the latter. A p-value of 0.19 indicated no significant difference in survival rates. Children with biventricular hearts had shorter ECMO durations but longer stays in the intensive care unit. The overall rate of complications on ECMO was higher in children with a single ventricle (odds ratio [OR] 1.57, 95% confidence interval [CI] 0.67-3.7); bleeding was the most common complication in both groups. The occurrence of a second ECMO run was more frequent in patients with a single ventricle (22% vs. 9.6%). ECMO can be effective for children with congenital heart defects, including single-ventricle patients. Bleeding remains a serious complication associated with worse outcomes. Patients requiring a second ECMO run within 30 days have lower survival rates.

Risk Factors and Outcome of Pulmonary Artery Stenting After Bidirectional Cavopulmonary Connection (BDCPC) in Single Ventricle Circulation.

After bidirectional cavopulmonary connection (BDCPC) central pulmonary arteries (PAs) of single ventricle (SV) patients can be affected by stenosis or even closure. Aim of this study is to compare SV patients with and without PA-stent implantation post-BDCPC regarding risk factors for stent implantation and outcome. Single center, retrospective (2006-2021) study of 136 SV consecutive patients with and without PA-stent implantation post-BDCPC. Patient characteristics, risk factors for PA-stent implantation and PA growth were assessed comparing angiographic data pre-BDCPC and pre-TCPC. A total of 40/136 (29%) patients underwent PA-stent implantation at median (IQR) 14 (1.1-39.0) days post-BDCPC. 37/40 (92.5%) underwent LPA-stenting. Multiple regression analysis showed single LV patients to receive less likely PA-stents than single RV patients (OR 0.41; p = 0.05). Reduced LPA/BSA (mm/m2) and larger diameter of neo-ascending aorta pre-BDCPC were associated with an increased likelihood of PA-stent implantation post-BDCPC (OR 0.89, p = 0.03; OR 1.05, p = 0.001). Stent re-dilatation was performed in 36/40 (89%) after 1 (0.8-1.5) year. Pulmonary artery diameters pre-BDCPC were lower in the PA-stent group: McGoon (p < 0.001), Nakata (p < 0.001). Indexed pulmonary artery diameters increased equally in both groups but remained lower pre-TCPC in the PA-stent group: McGoon (p < 0.001), Nakata (p = 0.009), and Lower Lobe Index (p = 0.003). LPA and RPA grew symmetrically in both groups. Single RV, larger neo-ascending aorta, and small LPA pre- BDCPC are independent risk factors for PA-stent implantation post-BDCPC. Pulmonary artery diameters after PA-stent implantation and stent re-dilatation showed significant growth together with the contralateral side, but the PA-system remained symmetrically smaller in the stent group.

Clinical course after Fontan palliation: Single center experience

BackgroundThe Fontan procedure has been the standard palliation for single-ventricle patients. We aimed to investigate the short- and midterm outcomes of patients who underwent Fontan palliation. ObjectivesTo assess and analyze the clinical course, including length of stay, complications, and mortality of single ventricle patients undergoing Fontan Palliation. MethodsRetrospective review of all patients who underwent Fontan palliation at the University of Minnesota, 2006–2020. The primary outcomes measured were length of stay, complications, and Fontan failure. ResultsOf the 55 patients the median age of Fontan was 3.9 yrs [2.63, 4.19] and the most common diagnoses were hypoplastic left heart syndrome (n = 20, 36 %), double inlet left ventricle (n = 11, 20 %) and double outlet right ventricle (n = 8, 15 %). Twenty-Seven were right ventricle dominant, 23 were left ventricle dominant, and 5 had biventricular morphology. The median hospital stay was 11 days [8, 17.5], an ICU stay of 6.5 days [4,9]. Fourteen late complications occurred in 10 patients. Three, all with HLHS, had Fontan failure leading to heart transplant. Four died: two prior to hospital discharge, one 6.7 yrs post-Fontan, and one 27 days after transplantation. Right ventricle morphology was associated with prolonged ICU (P 0.05), prolonged hospital stay (P < 0.01), and complications resulting in Fontan failure (P < 0.01). ConclusionThe survival following Fontan completion in the current era is excellent, with an overall and transplant-free survival at 5 and 10 years were at 96 % and 93 %. However, it is clear that univentricular physiology continues to present challenges, and patients remain at risk for morbidity, especially for patients with right ventricle morphology.

Pre-operative enteral feeding in single-ventricle CHD patients and necrotising enterocolitis risk.

Enteral feeding prior to cardiac surgery has benefits in pre-operative and post-operative patient statuses. In 2020, to increase pre-operative feeding for single-ventricle patients prior to stage 1 palliation, an enteral feeding algorithm was created. The aim of this study is to monitor the impact of our practice change with the primary outcome of necrotising enterocolitis incidence from birth to 2 weeks following surgical intervention. This is a single-site, retrospective cohort study including patients from 1 March, 2018 to 1 July, 2022. Variables assessed include demographics, age at cardiac surgery, primary cardiac diagnosis, necrotising enterocolitis pre-operative and 2 weeks post-operative cardiac surgery, feeding route, feeding type, volume of trophic enteral feeds, and near-infrared spectroscopy. Following implementation of a pre-operative enteral feeding algorithm, the rate of neonates fed prior to surgery increased (39.5-75%, p = .001). The feedings included a mean volume of 28.24 ± 11.16 ml/kg/day, 83% fed breastmilk only, 44.4% tube fed, and 55.5% of infants had all oral feedings. Comparing enterally fed neonates and those not enterally fed, the necrotising enterocolitis incidence from birth to 2 weeks post-op was not significantly increased (p = 0.926). As a result of implementing our feeding algorithm, the frequency of infants fed prior to stage I Norwood or Hybrid surgeries increased to 75%, and there was no significant change in the incidence of necrotising enterocolitis. This study confirmed that pre-operative enteral feeds are safe and are not associated with increased incidence of necrotising enterocolitis.

Effects of cardiac growth on electrical dyssynchrony in the single ventricle patient

Single ventricle patients, including those with hypoplastic left heart syndrome (HLHS), typically undergo three palliative heart surgeries culminating in the Fontan procedure. HLHS is associated with high rates of morbidity and mortality, and many patients develop arrhythmias, electrical dyssynchrony, and eventually ventricular failure. However, the correlation between ventricular enlargement and electrical dysfunction in HLHS physiology remains poorly understood. Here we characterize the relationship between growth and electrophysiology in HLHS using computational modeling. We integrate a personalized finite element model, a volumetric growth model, and a personalized electrophysiology model to perform controlled in silico experiments. We show that right ventricle enlargement negatively affects QRS duration and interventricular dyssynchrony. Conversely, left ventricle enlargement can partially compensate for this dyssynchrony. These findings have potential implications on our understanding of the origins of electrical dyssynchrony and, ultimately, the treatment of HLHS patients.

CARD32: Fontan Assist Device: Investigation of hemodynamic effects and wall shear stress using a cardiovascular simulator with computational fluid dynamic coupling

Study: The Fontan Assist Device (FAD), comprising of two tiny axial pumps, has potential use for single-ventricle patients by providing support for pulmonary blood flow and mitigating chronic venous hypertension. This study examines the FAD’s effects on hemodynamics under various medications and provides a method to assess wall shear stress (WSS) on the Fontan structure throughout the cardiac cycle. Method: A 0D lumped parameter model of the Fontan circulation was created in Matlab Simulink and tuned from patient-specific clinical data. For FAD evaluation, two axial pumps were placed in the pulmonary arteries. Changes in hemodynamic conditions with FAD +/- medical therapy (vasodilator and/or diuretic) were modeled and compared to the baseline condition. For 3D analysis of the FAD in situ, the segmented Fontan anatomy was obtained for computational fluid dynamics (CFD) assessment in Ansys CFX. 0D and 3D models were coupled to account for physiological changes simulated in 0D on the 3D boundary conditions. The FAD was modelled as two cylindrical momentum sources. Result: In 0D: At baseline, cardiac output (CO) was 4.2 L/min, and Fontan pressure was 16 mmHg. With FAD, CO improved to 5.1 L/min and could reach higher with vasodilator. Venous pressure can be reduced to 8 mmHg when paring with diuretic treatment. FAD + vasodilator + diuretic achieved venous pressure of 12.4 mmHg, Fontan pressure of 12.1 mmHg and CO of 5.0 L/min. In 0D-3D: cardiac output increased to 5.2 L/min with FAD compared to 4.6 L/min without while WSS also increased from 2.33 Pa to 10.2 Pa in the right pulmonary arteries. Future work includes optimizing both the design and placement of the FAD.Figure 1. 0D model pressure waveform of baseline condition and with different medical treatmentsFigure 2. Shear stress of baseline conditionFigure 3. Shear stress with FAD treatment

Validity Study Comparing Polar Ignite’s® Estimated VO2max to Traditional Cardiopulmonary Exercise Testing in Normal Cardiac Anatomy &amp; Fontan Pediatric Patients

Cardiorespiratory fitness as represented by maximum oxygen uptake, VO2max, is considered the best indicator for overall cardiovascular health. Fitness technology such as wrist worn devices, now allows for an easy method to monitor an individual’s VO2max. This study sought to compare the estimated VO2max measurements from the Polar Ignite (Polar Electro Oy, Kempele, Finland) fitness watch (Polar Ignite) against the gold standard, cardiopulmonary exercise testing (CPET) in normal cardiac anatomy and Fontan pediatric patients. This single-center, prospective study enrolled patients with normal cardiac anatomy and single ventricle patients with Fontan palliation (Fontan) between 13-21 years. The Polar Ignite was fastened on the patient’s right or left wrist while supine and estimated VO2max was generated based on a non-exercise test (Polar Fitness Test). A maximal voluntary CPET using the standard Bruce Treadmill Protocol was then completed. Measurements from the two tests were compared using the intraclass correlation coefficient (ICC), Pearson correlation coefficient and Bland-Altman method. Forty-seven patients were enrolled, including n=36 (77%) normal cardiac patients and n=11 (23%) Fontan patients. The majority of participants were white (n=41, 87%) and female (n=36, 66%). Patients were 15.3±1.9 years old, weighed 65.7±16.6 kg, and were 168.0±10.4 cm tall on average. The mean estimated Polar Ignite VO2max and peak CPET VO2 was 43.9±6.1 ml/kg/min vs 37.7±8.2 ml/kg/min, respectively in the normal cardiac group, and 42.6±3.9 ml/kg/min vs 22.6±5.6 ml/kg/min, respectively in the Fontan group. We found poor validity (ICC=0.21) and a weak correlation (r=0.31, p=0.07) between VO2max measured by the Polar Ignite and CPET in the normal cardiac group and poor validity (ICC=0.08) and strong correlation (r=0.84, p=0.001) in the Fontan group. In Bland-Altman analyses, the mean bias between VO2max as measured by the Polar Ignite and CPET was 6.85 ml/kg/min among the normal cardiac group and 20.05 ml/kg/min among the Fontan group. The Polar Ignite overestimated VO2max compared to CPET in both the normal cardiac and Fontan groups and cannot replace formal testing.

Pre-Fontan Assessment Utilizing Combined Cardiac Catheterization and Cardiac MRI: Comparison to the Pre-Fontan Catheterization.

Single ventricle patients eligible for Fontan completion undergo pre-Fontan catheterization for hemodynamic and anatomic assessment prior to surgery. Cardiac magnetic resonance imaging may be used to evaluate pre-Fontan anatomy, physiology, and collateral burden. We describe our center's outcomes in patients undergoing pre-Fontan catheterization combined with cardiac magnetic resonance imaging. A retrospective review of patients undergoing pre-Fontan catheterization from 10/2018 to 04/2022 at Texas Children's Hospital was performed. Patients were divided into 2 groups: combined cardiac magnetic resonance imaging and catheterization (combined group) and those who underwent catheterization only (catheterization only group). There were 37 patients in the combined group and 40 in the catheterization only group. Both groups were similar in age and weight. Patients undergoing combined procedures received less contrast, and experienced less in-lab time, fluoroscopy time and catheterization procedure time. Median radiation exposure was lower in the combined procedure group but was not statistically significant. Intubation and total anesthesia times were higher in the combined procedure group. Patients undergoing a combined procedure were less likely to have collateral occlusion performed than in the catheterization only group. Bypass time, intensive care unit length of stay, and chest tube duration were similar in both groups at the time of Fontan completion. Combined pre-Fontan assessment decreases catheterization procedure and fluoroscopy time associated with cardiac catheterization at the expense of longer anesthetic times, and results in similar Fontan outcomes compared to when cardiac catheterization alone is utilized.

C43 RELATIONSHIP BETWEEN ECHOCARDIOGRAPHIC DATA AND CARDIOPULMONARY EXERCISE TEST PARAMETERS IN ADULT CONGENITAL HEART DISEASE PATIENTS: A RETROSPECTIVE CLINICAL STUDY

Abstract Introduction The interpretation of cardiopulmonary exercise test (CPET) in adult congenital heart disease (ACHD) is challenging because of the high variability in cardiac lesions and because the poor exercise tolerance is often associated with abnormal heart function. The aim of this work is to study the correlation between echocardiographic evaluation and CPET parameters in ACHD population. Methods This is a retrospective clinical study enrolling all ACHD patients afferent to our institution from March 2016 to February 2020 collecting clinical, CPET and echocardiographic data. Population was divided into three groups and compared: patients with prevalent left heart lesions (L group), patients with prevalent right heart lesions (R group) and patients with single ventricle physiology (SV group). Finally, correlation analysis were performed to assess any relationship between echocardiographic and CPET data. Results 60 patients were included in the study, 20 were male, median age was 36 [30–46.75] years old, 23 had a prevalent left side pathology, 31 a prevalent right side pathology and 6 had a single ventricle physiology. L group had a significantly lower predicted peak VO2 in comparison to SV group (p=0.03). Statistical analysis showed a correlation between the right ventricular function and the ventilatory reserve in the R group (R2 0.517). In SV group we found correlation between ventricular–arterial coupling and Cardiac mechanical efficiency with the ventilatory reserve (R2 0.6 and 0.65, respectively) and the oxygen pulse (R2 0.97 and 0.98, respectively), and a correlation between the ejection fraction and the Oxygen pulse (R2 0.52). Finally, a correlation between the TAPSE/PAPs index and the ventilation (R2=0.79), the ratio between the oxygen uptake and the workload (R2=0.61) and the oxygen consumption (R2=0.72) was found. Coclusion:In our preliminary experience, echocardiographic parameters of cardiocirculatory efficiency correlate with the oxygen consumption per heart beat evaluated at the CPET in single ventricle patients, and the breath rate is influenced not only by ventricular function but also by the coupling between the ventricle and the arterial system. In patients affected by right–side disease, the breath rate correlate with the right ventricular function. Finally, in the left heart lesion population, a correlation between the TAPSE/PAPs index with the ventilation, the oxygen consumption per beat and the oxygen consumption was found.

D-14 | Atrial Septal Interventions During and After Hybrid Stage I Palliation

Hybrid stage I palliation (HS1P) is an alternative approach for single ventricle (SV) patients, particularly those with high-risk factors. Unlike surgical stage I palliation where atrial septectomy is standardly performed, the approach to atrial septal intervention (ASI) during HS1P is patient dependent. In this study, we aimed to describe the frequency of interventions on the atrial septum both at the time of the HS1P and during the interstage period and to determine factors associated with a need for ASI post-HS1P. A retrospective study was performed in all SV patients who underwent HS1P at our center in the past 12 years. Initial and subsequent interventions on the atrial septum were collected through either surgical Norwood or Comprehensive stage II. Patient factors, atrial septal characteristics by echo, and type of atrial septal intervention were also collected and compared to identify risk factors for ASI intervention post-HS1P. Of 50 SV patients included, about half of the patients (26/50) required an ASI post-HS1P; 23 (46%) had an ASI performed at the time of HS1P, and 7 (27%) of these patients required a subsequent ASI. Of the 27 patients who did not undergo an initial ASI, 19 (70%) required a subsequent ASI. Compared to static and cutting balloon septoplasty, balloon atrial septostomy and atrial septal stent placement were associated with a decreased risk of need for ASI post-HS1P (both p<0.05). There were no significant differences in patient characteristics, hospital course, or overall outcomes between patients who required ASI post-HS1P vs. those who did not. Atrial septal intervention after HS1P is common but has little impact on patient outcomes through the next stage of palliation. Although no patient or anatomic factors were identified risk factors for atrial septal intervention post-HS1P (besides having an intact atrial septum), intervention with either balloon atrial septostomy or atrial septal stent placement was associated with a lower need for atrial septal reintervention and therefore may be the preferred approach when anatomically feasible.

Pre-Glenn aorto-pulmonary collaterals in single-ventricle patients.

In single-ventricle patients undergoing staged-bidirectional Glenn, 36-59% have aorto-pulmonary collateral flow, but risk factors and clinical outcomes are unknown. We hypothesise that shunt type and catheter haemodynamics may predict pre-bidirectional Glenn aorto-pulmonary collateral burden, which may predict death/transplantation, pulmonary artery or aorto-pulmonary collateral intervention. Retrospective cohort study of patients undergoing a Norwood procedure for single-ventricle anatomy. Covariates included clinical and haemodynamic characteristics up to/including pre-bidirectional Glenn catheterisation and aorto-pulmonary collateral burden at pre-bidirectional Glenn catheterisation. Multivariable models used to evaluate relationships between risk factors and outcomes. From January 2011 to March 2016, 104 patients underwent Norwood intervention. Male sex (odds ratio 3.36, 95% confidence interval 1.17-11.4), age at pre-bidirectional Glenn assessment (2.12, 1.33-3.39 per month), and pulmonary to systemic flow ratio (1.23, 1.08-1.41 per 0.1 unit) were associated with aorto-pulmonary collateral burden. Aorto-pulmonary collateral burden was not associated with death/transplantation (hazard ratio 1.19, 95% confidence interval 0.37-3.85), pulmonary artery (sub-hazard ratio 1.38, 0.32-2.61), or aorto-pulmonary collateral interventions (sub-hazard ratio 1.11, 0.21-5.76). Longer post-Norwood length of stay was associated with greater risk of death/transplantation (hazard ratio 1.22 per week, 95% confidence interval 1.08-1.38), but lower risk of aorto-pulmonary collateral intervention (sub-hazard ratio 0.86 per week, 95% confidence interval 0.75-0.98). Time to pre-bidirectional Glenn catheterisation was associated with lower risk of pulmonary artery (sub-hazard ratio 0.80 per month, 95% confidence interval 0.65-0.98) and aorto-pulmonary collateral intervention (sub-hazard ratio 0.79, 0.63-0.99). Probability of moderate/severe aorto-pulmonary collateral burden increased with left-to-right shunt (22.5% at <1.0, 57.6% at >1.4) and the age at pre-bidirectional Glenn catheterisation (10.6% at <2 months, 56.9% at >5 months). Aorto-pulmonary collateral burden is common after Norwood procedure and increases as age at bidirectional Glenn increases. As expected, higher pulmonary to systemic flow ratio is a marker for greater aorto-pulmonary collateral burden pre-bi-directional Glenn; aorto-pulmonary collateral burden does not confer risk of death/transplantation or pulmonary artery intervention.

Hospital resource utilization in a national cohort of functionally single ventricle patients undergoing surgical treatment

ObjectiveThe study objective was to provide a detailed overview of health resource use from birth to 18 years old for patients with functionally single ventricles and identify associated risk factors. MethodsAll patients with functionally single ventricles treated between 2000 and 2017 in England and Wales were linked to hospital and outpatient records using data from the Linking AUdit and National datasets in Congenital HEart Services project. Hospital stay was described in yearly age intervals, and associated risk factors were explored using quantile regression. ResultsA total of 3037 patients with functionally single ventricles were included, 1409 (46.3%) undergoing a Fontan procedure. During the first year of life, the median days spent in hospital was 60 (interquartile range, 37-102), mostly inpatient days, mirroring a mortality of 22.8%. This decreases to between 2 and 9 in-hospital days/year afterward. Between 2 and 18 years, most hospital days were outpatient, with a median of 1 to 5 days/year. Lower age at the first procedure, hypoplastic left heart syndrome/mitral atresia, unbalanced atrioventricular septal defect, preterm birth, congenital/acquired comorbidities, additional cardiac risk factors, and severity of illness markers were associated with fewer days at home and more intensive care unit days in the first year of life. Only markers of early severe illness were associated with fewer days at home in the first 6 months after the Fontan procedure. ConclusionsHospital resource use in functionally single ventricle cases is not uniform, decreasing 10-fold during adolescence compared with the first year of life. There are subsets of patients with worse outcomes during their first year of life or with persistently high hospital use throughout their childhood, which could be the target of future research.

(1111) Long-Term Experience with Heart Transplantation in Patients with Congenital Heart Disease - Focus on Single Ventricle Patients and Vad

(1111) Long-Term Experience with Heart Transplantation in Patients with Congenital Heart Disease - Focus on Single Ventricle Patients and Vad

The prevalence of abnormal spirometry in children with CHD.

The burden of pulmonary disease in children with CHD remains under-recognised. Studies have examined children with single ventricle and two ventricle heart disease and documented a decreased forced vital capacity. Our study sought to further explore the pulmonary function of children with CHD. A retrospective review was performed of spirometry in CHD patients over a 3-year period. Spirometry data were corrected for size, age, and gender and analysed using z-scores. The spirometry of 260 patients was analysed. About 31% had single ventricle (n = 80, 13.6 years (interquartile range 11.5-16.8)) and 69% had two ventricle circulation (n = 180, 14.4 years (interquartile range 12.0-17.3)). Single ventricle patients were found to have a lower median forced vital capacity z-score compared to two ventricle patients (p = 0.0133). The prevalence of an abnormal forced vital capacity was 41% in single ventricle patients and 29% in two ventricle patients. Two ventricle patients with tetralogy of Fallot and truncus arteriosus had similar low forced vital capacity comparable to single ventricle patients. The number of cardiac surgeries predicted an abnormal forced vital capacity in two ventricle patients except tetralogy of Fallot patients. Pulmonary morbidity in patients with CHD is common with a decreased forced vital capacity noted in single ventricle and two ventricle patients. Forced vital capacity is lower in patients with single ventricle circulation; however, two ventricle patients with tetralogy of Fallot or truncus arteriosus have similar lung function in comparison to the single ventricle group. The number of surgical interventions was predictive of forced vital capacity z-score in some but not all two ventricle patients and not predictive in single ventricle patients suggesting a multifactorial to pulmonary disease in children with CHD.

Prevalence of Abnormal Hemoglobin A1c Values in Single Ventricle Patients Following Fontan Palliation

Fontan palliation has improved survival in single ventricle patients. However, Fontan patients are subject to long-term morbidity. A few previous studies suggest Fontan patients have an increased risk of abnormal glucose metabolism without a clear mechanism. We aim to evaluate the prevalence and severity of abnormal hemoglobin A1c (HbA1c) values in Fontan patients and identify associated factors. Single-center retrospective cross-sectional cohort study including Fontan patients and documented HbA1c testing. Univariate demographic, anthropometric, and laboratory variable comparisons were completed and a stepwise selection multivariate regression model was attempted. The study included 414 Fontan patients, median age of 19years (range 3-59years). Of these, 190 patients (60.5% male) had at least one HbA1c. Abnormal HbA1c (> 5.6%) was found in 36% (n = 70) and diabetic-range HbA1c (≥ 6.5%) in 4.7% (n = 9). Factors associated with abnormal HbA1c included non-white race (63% vs 45%, p = 0.018), female sex (49% vs 34%, p = 0.050), elevated adult BMI [29.6 (± 8.4) vs 24.8 (± 4.8), p = < 0.0001], elevated blood glucose [108.7 (± 47.3) vs 91.1 (± 17.9), p = < 0.0001], and elevated triglycerides [101.5 (± 52.9) vs 84.1 (± 50.9), p = 0.029]. There were no significant differences found between the two HbA1c groups regarding cardiac diagnoses or surgical factors including type of stage 1 procedure, type of stage 3 procedure, or fenestration of Fontan. Patient age at time of initial Fontan procedure and time since initial Fontan showed no association with abnormal glucose metabolism. Obesity (BMI z-score ≥ 1.6 in children and BMI ≥ 30 in adults) was correlated with abnormal HbA1c (p = 0.008, 95%CI 0.069-0.45). There is a high prevalence of elevated HbA1c values in Fontan patients with modifiable associated factors, such as obesity and hypertriglyceridemia. Further investigation is needed to identify additional associated factors for abnormal glucose metabolism and determine its clinical significance. Lastly, we propose a new management protocol to screen for abnormal glucose metabolism.

In Silico Evaluation of a Self-powered Venous Ejector Pump for Fontan Patients.

The Fontan circulation carries a dismal prognosis in the long term due to its peculiar physiology and lack of a subpulmonic ventricle. Although it is multifactorial, elevated IVC pressure is accepted to be the primary cause of Fontan's high mortality and morbidity. This study presents a self-powered venous ejector pump (VEP) that can be used to lower the high IVC venous pressure in single-ventricle patients. A self-powered venous assist device that exploits the high-energy aortic flow to lower IVC pressure is designed. The proposed design is clinically feasible, simple in structure, and is powered intracorporeally. The device's performance in reducing IVC pressure is assessed by conducting comprehensive computational fluid dynamics simulations in idealized total cavopulmonary connections with different offsets. The device was finally applied to complex 3D reconstructed patient-specific TCPC models to validate its performance. The assist device provided a significant IVC pressure drop of more than 3.2mm Hg in both idealized and patient-specific geometries, while maintaining a high systemic oxygen saturation of more than 90%. The simulations revealed no significant caval pressure rise (< 0.1mm Hg) and sufficient systemic oxygen saturation (> 84%) in the event of device failure, demonstrating its fail-safe feature. A self-powered venous assist with promising in silico performance in improving Fontan hemodynamics is proposed. Due to its passive nature, the device has the potential to provide palliation for the growing population of patients with failing Fontan.

Current diagnostic and therapeutic strategies for the management of lymphatic insufficiency in patients with hypoplastic left heart syndrome.

Children with hypoplastic left heart syndrome share unique hemodynamic features that alter lymphatic integrity at all stages of palliation. Lymphatic congestion is almost universal in this patient group to some extent. It may lead to reversal of lymphatic flow, the development of abnormal lymphatic channels and ultimately decompression and loss of protein rich lymphatic fluid into extra lymphatic compartments in prone individuals. Some of the most devastating complications that are associated with single ventricle physiology, notably plastic bronchitis and protein losing enteropathy, have now been proven to be lymphatic in origin. Based on the new pathophysiologic concept new diagnostic and therapeutic strategies have recently been developed. Dynamic contrast magnetic resonance lymphangiography is now mainstay in diagnosis of lymphatic insufficiency and allows a thorough assessment of anatomy and function of the main lymphatic compartments through intranodal, intrahepatic and intramesenteric lymphatic imaging. Contrast enhanced ultrasound can evaluate thoracic duct patency and conventional fluoroscopic lymphangiography has been refined for evaluation of patients where magnetic resonance imaging cannot be performed. Novel lymphatic interventional techniques, such as thoracic duct embolization, selective lymphatic duct embolization and liver lymphatic embolization allow to seal abnormal lymphatic networks minimally invasive and have shown to resolve symptoms. Innominate vein turn-down procedures, whether surgical or interventional, have been designed to reduce lymphatic afterload and increase systemic preload effectively in the failing Fontan circulation. Outflow obstruction can now be managed with new microsurgical techniques that create lympho-venous anastomosis. Short term results for all of these new approaches are overall promising but evidence is sparse and long-term outcome still has to be defined. This review article aims to summarize current concepts of lymphatic flow disorders in single ventricle patients, discuss new emerging diagnostic and therapeutic strategies and point out lacks in evidence and needs for further research on this rapidly growing topic.

Contemporary Outcomes of Tracheostomy in Patients With Single Ventricle Heart Lesions.

Approximately 0.2% to 2.7% of children with congenital heart disease require a tracheostomy after cardiac surgery with the majority having single ventricle (SV) type heart lesions. Tracheostomy in SV patients is reported to be associated with high mortality. We hypothesized that short- and long-term survival of patients with SV heart disease would vary according to tracheostomy indication. This is a single center, 20-year, retrospective review of all patients with SV heart disease who underwent tracheostomy. Demographic, cardiac anatomy, surgical, intensive care unit, and hospital course data were collected. The primary outcome was survival following tracheostomy. Secondary outcome was the completion of staged palliation to Fontan. In total, 25 patients with SV heart disease who underwent tracheostomy were included. Indications for tracheostomy included one or more of the following: tracheobronchomalacia (n = 8), vocal cord paralysis (n = 7), tracheal/subglottic stenosis (n = 6), primary respiratory insufficiency (n = 4), diaphragm paralysis (n = 3), suboptimal hemodynamics (n = 2), and other upper airway issues (n = 1). Survival at six months, one year, five years, and ten years was 76%, 68%, 63%, and 49%, respectively. Most patients completed Fontan palliation (64%). Patients who underwent tracheostomy for suboptimal hemodynamics and/or respiratory insufficiency had a higher mortality risk compared to those with indications of upper airway obstruction or diaphragm paralysis (hazard ratio 4.1, 95% confidence interval 1.2-13.7; P = .02). Mortality risk varies according to tracheostomy indication in patients with SV heart disease. Tracheostomy may allow staged surgical palliation to proceed with acceptable risk if it was indicated for anatomic or functional airway dysfunction.

Prolonged Enteral Tube Feeding in Infants With a Functional Single Ventricle Is Associated With Adverse Outcomes After Fontan Completion

To define the baseline characteristics of long-term tube-fed (TF) single ventricle patients, investigate associations between long-term enteral tube feeding and growth, and determine associations with long-term outcomes after Fontan procedure. We performed a retrospective cohort study of patients in the Australia and New Zealand Fontan Registry undergoing treatment at the Royal Children's Hospital, the Children's Hospital at Westmead, Royal Melbourne Hospital, and Royal Prince Alfred Hospital from 1981 to 2018. Patients were defined as TF or non-tube-fed (NTF) based on enteral tube feeding at the age of 90days. Feeding groups were compared regarding body mass index (BMI) trajectory, BMI at last follow-up, and long-term incidence of severe Fontan failure. Of 390 patients (56 [14%] TF, 334 [86%] NTF), TF was associated with right ventricular dominance, hypoplastic left heart syndrome, Norwood procedure, increased procedures prior to Fontan, extracardiac conduit Fontan, Fontan fenestration, and atrioventricular valve repair/replacement. TF patients were less likely to be in the higher compared with lowest 0-6month BMI trajectory (P<.01; P=.03), had lower 6month weight-for-age z-scores (P<.01) and length-for-age z-scores (P=.01). TF were less likely to be overweight/obese at pediatric follow-up (hazard ratio [HR]=0.31, 95% CI: 0.12-0.80; P=.02) and more likely to be underweight at adult follow-up (HR=16.51; 5% CI: 2.70-101.10; P<.01). TF compared with NTF was associated with increased risk of severe Fontan failure (HR=4.13; 95% CI=1.65-10.31; P<.01). Prolonged infant enteral tube feeding is an independent marker of poor growth and adverse clinical outcomes extending long-term post-Fontan procedure.

In-Silico and In-Vitro Analysis of the Novel Hybrid Comprehensive Stage II Operation for Single Ventricle Circulation

Single ventricle (SV) anomalies account for one-fourth of all congenital heart disease cases. The existing palliative treatment for this anomaly achieves a survival rate of only 50%. To reduce the trauma associated with surgical management, the hybrid comprehensive stage II (HCSII) operation was designed as an alternative for a select subset of SV patients with the adequate antegrade aortic flow. This study aims to provide better insight into the hemodynamics of HCSII patients utilizing a multiscale Computational Fluid Dynamics (CFD) model and a mock flow loop (MFL). Both 3D-0D loosely coupled CFD and MFL models have been tuned to match baseline hemodynamic parameters obtained from patient-specific catheterization data. The hemodynamic findings from clinical data closely match the in-vitro and in-silico measurements and show a strong correlation (r = 0.9). The geometrical modification applied to the models had little effect on the oxygen delivery. Similarly, the particle residence time study reveals that particles injected in the main pulmonary artery (MPA) have successfully ejected within one cardiac cycle, and no pathological flows were observed.