Long-term incidence of arrhythmias in extracardiac conduit Fontan and comparison between systemic left and right ventricle.

AIMS: The extracardiac conduit-Fontan (ECC) has become the preferred technique for univentricular heart palliation, but there are currently no data on the incidence of long-term arrhythmias. This study investigated the incidence of arrhythmias and relation to single ventricle morphology in the long-term follow-up (FU) in ECC. METHODS AND RESULTS: All patients with ECC performed in our Centre between 1987 and 2017 were included (minimum FU 5 years). Of 353 consecutive patients, 303 [57.8% males, aging 8-50 (median 20) years at last FU] were considered and divided into two groups depending on left (194 in Group 1) or right (109 in Group 2) ventricular morphology. Eighty-five (28%) experienced ≥1 arrhythmic complications, with early and late arrhythmias in 17 (5.6%) and 73 (24.1%) patients, respectively. Notably, late bradyarrhythmias occurred after 6 years in 21 (11%) patients in Group 1, and in 15 (13.8%) in Group 2 [P = 0.48]. Late tachyarrhythmias occurred in 55 (18.2%) patients after 12 years: 33 (17%) in Group 1 and 22 (20.2%) patients in Group 2 [P  = 0.5]. Ventricular tachycardias (VT) were documented after 12.5 years in 14 (7.2%) patients of Group 1 and 15 (13.8%) of Group 2 [P = 0.06] with a higher incidence in Group 2 during the FU [P = 0.005]. CONCLUSION: Extracardiac conduit is related to a significant arrhythmic risk in the long-term FU, higher than previously reported. Bradyarrhythmias occur earlier but are less frequent than tachyarrhythmias. Interestingly, patients with systemic right ventricle have a significantly higher incidence of VT, especially in a very long FU.

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

BACKGROUND: In the Fontan palliation for single ventricle heart disease (SVHD), pulmonary blood flow is non-pulsatile/passive, low velocity, and low shear, making viscous power loss a critical determinant of cardiac output. The rheologic properties of blood in SVHD patients are essential for understanding and modulating their limited cardiac output and they have not been systematically studied. We hypothesize that viscosity is decreased in single ventricle circulation. METHODS: We evaluated whole blood viscosity, red blood cell (RBC) aggregation, and RBC deformability to evaluate changes in healthy children and SVHD patients. We altered suspending media to understand cellular and plasma differences contributing to rheologic differences. RESULTS: Whole blood viscosity was similar between SVHD and healthy at their native hematocrits, while viscosity was lower at equivalent hematocrits for SVHD patients. RBC deformability is increased, and RBC aggregation is decreased in SVHD patients. Suspending SVHD RBCs in healthy plasma resulted in increased RBC aggregation and suspending healthy RBCs in SVHD plasma resulted in lower RBC aggregation. CONCLUSIONS: Hematocrit corrected blood viscosity is lower in SVHD vs. healthy due to decreased RBC aggregation and higher RBC deformability, a viscous adaptation of blood in patients whose cardiac output is dependent on minimizing viscous power loss. IMPACT: Patients with single ventricle circulation have decreased red blood cell aggregation and increased red blood cell deformability, both of which result in a decrease in blood viscosity across a large shear rate range. Since the unique Fontan circulation has very low-shear and low velocity flow in the pulmonary arteries, blood viscosity plays an increased role in vascular resistance, therefore this work is the first to describe a novel mechanism to target pulmonary vascular resistance as a modifiable risk factor. This is a novel, modifiable risk factor in this patient population.

Long-term outcomes of atrioventricular septal defect and single ventricle: A multicenter study.

OBJECTIVE: The study objective was to analyze survival and incidence of Fontan completion of patients with single-ventricle and concomitant unbalanced atrioventricular septal defect. METHODS: Data from 4 Dutch and 3 Belgian institutional databases were retrospectively collected. A total of 151 patients with single-ventricle atrioventricular septal defect were selected; 36 patients underwent an atrioventricular valve procedure (valve surgery group). End points were survival, incidence of Fontan completion, and freedom from atrioventricular valve reoperation. RESULTS: Median follow-up was 13.4 years. Cumulative survival was 71.2%, 70%, and 68.5% at 10, 15, and 20 years, respectively. An atrioventricular valve procedure was not a risk factor for mortality. Patients with moderate-severe or severe atrioventricular valve regurgitation at echocardiographic follow-up had a significantly worse 15-year survival (58.3%) compared with patients with no or mild regurgitation (89.2%) and patients with moderate regurgitation (88.6%) (P = .033). Cumulative incidence of Fontan completion was 56.5%, 71%, and 77.6% at 5, 10, and 15 years, respectively. An atrioventricular valve procedure was not associated with the incidence of Fontan completion. In the valve surgery group, freedom from atrioventricular valve reoperation was 85.7% at 1 year and 52.6% at 5 years. CONCLUSIONS: The long-term survival and incidence of Fontan completion in our study were better than previously described for patients with single-ventricle atrioventricular septal defect. A concomitant atrioventricular valve procedure did not increase the mortality rate or decrease the incidence of Fontan completion, whereas patients with moderate-severe or severe valve regurgitation at follow-up had a worse survival. Therefore, in patients with single-ventricle atrioventricular septal defect when atrioventricular valve regurgitation exceeds a moderate degree, the atrioventricular valve should be repaired.

Ability of Video Telemetry to Predict Unplanned Hospital Admissions for Single Ventricle Infants.

Background Our Cardiac High Acuity Monitoring Program (CHAMP) uses home video telemetry (HVT) as an adjunct to monitor infants with single ventricle during the interstage period. This study describes the development of an objective early warning score using HVT, for identification of infants with single ventricle at risk for clinical deterioration and unplanned hospital admissions (UHA). Methods and Results Six candidate scoring parameters were selected to develop a pragmatic score for routine evaluation of HVT during the interstage period. We evaluated the individual and combined ability of these parameters to predict UHA. All infants with single ventricle monitored at home by CHAMP between March 2014 and March 2018 were included. Videos obtained within 48 hours before UHA were compared with videos obtained at baseline. We used binary logistic regression models and receiver operating characteristic curves to evaluate the parameters' performance in discriminating the outcome of interest. Thirty-nine subjects with 64 UHA were included. We compared 64 pre-admission videos to 64 paired baseline videos. Scoring was feasible for a mean of 91.6% (83.6%-98%) of all observations. Three different HVT score models were proposed, and a final model composed of respiratory rate, respiratory effort, color, and behavior exhibited an excellent discriminatory capability with an area under the receiver operating characteristic curve of 93% (89%-98%). HVT score of 5 was associated with specificity of 93.8% and sensitivity of 88.7% in predicting UHA. Conclusions We developed a feasible and reproducible HVT score that can serve as a tool to predict UHA in infants with single ventricle. Future directions involve prospective, multicenter validation of this tool.

Automated Prediction of Cardiorespiratory Deterioration in Patients With Single Ventricle.

BACKGROUND: Patients with single-ventricle physiology have a significant risk of cardiorespiratory deterioration between their first and second stage palliation surgeries. OBJECTIVES: The objective of this study is to develop and validate a real-time computer algorithm that can automatically recognize physiological precursors of cardiorespiratory deterioration in children with single-ventricle physiology during their interstage hospitalization. METHODS: A retrospective study was conducted from prospectively collected physiological data of subjects with single-ventricle physiology. Deterioration events were defined as a cardiac arrest requiring cardiopulmonary resuscitation or an unplanned intubation. Physiological metrics were derived from the electrocardiogram (heart rate, heart rate variability, ST-segment elevation, and ST-segment variability) and the photoplethysmogram (peripheral oxygen saturation and pleth variability index). A logistic regression model was trained to separate the physiological dynamics of the pre-deterioration phase from all other data generated by study subjects. Data were split 50/50 into model training and validation sets to enable independent model validation. RESULTS: Our cohort consisted of 238 subjects admitted to the cardiac intensive care unit and stepdown units of Texas Children's Hospital over a period of 6 years. Approximately 300,000 h of high-resolution physiological waveform and vital sign data were collected using the Sickbay software platform (Medical Informatics Corp., Houston, Texas). A total of 112 cardiorespiratory deterioration events were observed. Seventy-two of the subjects experienced at least 1 deterioration event. The risk index metric generated by our optimized algorithm was found to be both sensitive and specific for detecting impending events 1 to 2 h in advance of overt extremis (receiver-operating characteristic curve area: 0.958; 95% confidence interval: 0.950 to 0.965). CONCLUSIONS: Our algorithm can provide 1 to 2 h of advanced warning for 62% of all cardiorespiratory deterioration events in children with single-ventricle physiology during their interstage period, with only 1 alarm being generated at the bedside per patient per day.

Imposition of Fontan physiology: Effects on strain and global measures of ventricular function.

OBJECTIVE: We sought to evaluate contractile function in single-ventricle patients before and after imposition of Fontan physiology. METHODS: Single right ventricle (SRV; n = 38) and single left ventricle (SLV; n = 11) patients underwent cardiac magnetic resonance imaging pre and post Fontan operation. Global radial strain (GRS), global circumferential strain (GCS), and global longitudinal strain were measured along with ejection fraction (EF) and atrioventricular valve regurgitation (AVVR). RESULTS: Age at cardiac magnetic resonance imaging before the Fontan operation was 3.1 ± 1.3 years and after the Fontan procedure was 5.8 ± 2.7 years. There were no significant EF differences between SRV and SLV patients before and after the Fontan procedure, and EF did not deteriorate significantly after the Fontan operation. GRS was significantly lower for SRV patients than for SLV patients before (24.3% vs 32.1%; P = .048) and after (21.8% vs 29.7%; P = .045) the Fontan procedure. GRS and GCS of the SRV patients deteriorated significantly after the Fontan operation (GRS, P = .01; GCS, P = .009). Strains showed positive correlations before and after the Fontan operation with positive correlations among each strain. Within all patients, strains correlated positively with EF. Strains and EF negatively correlated with AVVR (GRS P = .03, r = -0.22; GCS P = .03, r = -0.23; EF P < .001, r = -0.37). CONCLUSIONS: Strains were lower for SRV than for SLV patients before and after the Fontan operation and deteriorated after the Fontan operation. Our study suggests that strain measures might detect ventricular deterioration earlier than EF. Because strains before and after the Fontan operation were positively correlated, and negatively correlated with AVVR, the early institution of myocardial protective therapy including AVVR management, especially for SRV patients, might have benefit.

Total vascular resistance increases during volume-unloading in asymptomatic single ventricle patients.

OBJECTIVE: While the surgical stages of single ventricle (SV) palliation serve to separate pulmonary venous and systemic venous return, and to volume-unload the SV, staged palliation also results in transition from parallel to series circulation, increasing total vascular resistance. How this transition affects pressure loading of the SV is as yet unreported. METHODS: We performed a retrospective chart review of Stage I, II, and III cardiac catheterization (CC) and echocardiographic data from 2001-2017 in all SV pts, with focus on systemic, pulmonary, and total vascular resistance (SVR, PVR, TVR respectively). Longitudinal analyses were performed with log-transformed variables. Effects of SVR-lowering medications were analyzed using Wilcoxon rank-sum testing. RESULTS: There were 372 total patients who underwent CC at a Stage I (median age of 4.4 months, n=310), Stage II (median age 2.7 years, n = 244), and Stage III (median age 7.3 years, n = 113). Total volume loading decreases with progression to Stage III (P< 0.001). While PVR gradually increases from Stage II to Stage III, and SVR increases from Stage I to Stage III, TVR dramatically increases with progress towards series circulation. TVR was not affected by use of systemic vasodilator therapy. TVR, PVR, SVR, and CI did not correlate with indices of SV function at Stage III. CONCLUSIONS: TVR steadily increases with an increasing contribution from SVR over progressive stages. TVR was not affected by systemic vasodilator agents. TVR did not correlate with echo-based indices of SV function. Further studies are needed to see if modulating TVR can improve exercise tolerance and outcomes.

Assessment of pressure-volume relations in univentricular hearts: Comparison of obtainment by real-time 3D echocardiography and mini pressure-wire with conductance technology.

OBJECTIVES: The gold standard to obtain pressure-volume relations (PVR) of the heart, the conductance technology (PVRCond), is rarely used in children. PVR can also be obtained by 3D-echocardiography volume data combined with simultaneously measured pressure data by a mini pressure-wire (PVR3DE). We sought to investigate the feasibility of both methods in patients with univentricular hearts and to compare them, including hemodynamic changes. METHODS: We studied 19 patients (age 2-29 years). PVR3DE and PVRCond were assessed under baseline conditions and stimulation with dobutamine. RESULTS: Obtaining PVR3DE was successful in all patients. Obtaining PVRCond was possible in 15 patients during baseline (79%) and in 12 patients under dobutamine (63%). Both methods showed that end-systolic elastance (Ees) and arterial elastance (Ea) increased under dobutamine and that Tau showed a statistically significant decrease. Intraclass correlation (95% confidence interval) showed moderate to good agreement between methods: Ees: 0.873 (0.711-0.945), Ea: 0.709 (0.336-0.873), Tau: 0.867 (0.697-0.942). Bland-Altman analyses showed an acceptable bias with wider limits of agreement: Ees: 1.63 mmHg/ml (-3.83-7.08 mmHg/ml), Ea: 0.53 mmHg/ml (-5.23-6.28 mmHg/ml), Tau: -0,76 ms (-10.73-9.21 ms). CONCLUSION: Changes of PVR-specific parameters under dobutamine stimulation were reflected in the same way by both methods. However, the absolute values for these parameters could vary between methods and, therefore, methods are not interchangeable. Obtaining PVR3DE in a single ventricle was easier, faster and more successful than PVRCond. PVR3DE provides a promising and needed alternative to the conductance technology for the assessment of cardiac function in univentricular hearts.

The impact of additional antegrade pulmonary blood flow at bidirectional Glenn shunt on long-term outcomes.

OBJECTIVES: We investigated the impact of additional antegrade pulmonary blood flow on the long-term outcomes after bidirectional Glenn shunt. METHODS: From 2001 to 2015, 279 patients underwent bidirectional Glenn shunt as an interim palliation for a functionally single ventricle. After excluding patients with a previous Kawashima or Norwood operation, 202 patients with preexisting antegrade pulmonary blood flow before bidirectional Glenn shunt were included in this study. Antegrade pulmonary blood flow was eliminated in 110 patients (no antegrade pulmonary blood flow group) and maintained in 92 patients (antegrade pulmonary blood flow group). The impact of antegrade pulmonary blood flow at bidirectional Glenn shunt on long-term outcome was analyzed using inverse probability of treatment weighting. RESULTS: Median age and body weight at bidirectional Glenn shunt were 8 months and 7.8 kg, respectively. Prolonged chest tube drainage or readmission for effusion after bidirectional Glenn shunt was more frequent in the antegrade pulmonary blood flow group (odds ratio, 3.067; 95% confidence interval, 1.036-9.073; P = .043). In the no antegrade pulmonary blood flow group, B-type natriuretic peptide level was decreased further until the Fontan operation (P = .012). In the no antegrade pulmonary blood flow group, oxygen saturation was lower just after bidirectional Glenn shunt, although it was increased further until Fontan operation (P < .001), despite still lower oxygen saturation before Fontan operation compared with antegrade pulmonary blood flow group (P < .001). The McGoon ratio was decreased in both groups without intergroup difference, although the McGoon ratio before Fontan operation was higher in the antegrade pulmonary blood flow group (2.3 ± 0.4 vs 2.1 ± 0.4, P = .008). Overall transplant-free survival was worse in the antegrade pulmonary blood flow group (hazard ratio, 2.37; confidence interval, 1.089-5.152; P = .030). CONCLUSIONS: Maintaining antegrade pulmonary blood flow at bidirectional Glenn shunt was beneficial for higher oxygen saturation and larger pulmonary artery size before Fontan operation. However, it was unfavorable for overall transplant-free survival with a sustained higher risk of death or transplant until the elimination of antegrade pulmonary blood flow.

Assessing Single Ventricle Function in the Fontan Circulation using Wave Intensity Analysis.

Single ventricle hearts palliated with the Fontan operation present complications later in life as a result of increased venous pressures and abnormal ventricle function. Wave intensity analysis uses measurements of blood velocity and pressure to represent arterial hemodynamics as summations of energy waves. This methodology could potentially be a useful tool in assessment of Fontan patients. The clinical value of wave intensity parameters was utilized to evaluate the functional performance of the single ventricle in Fontan patients. A retrospective analysis of invasive hemodynamic data was retrospectively obtained from routine cardiac catheterization of patients with Fontan circulation (n = 20) and comparison to those with biventricular circulation (n = 10) who presented to the catheterization laboratory for closure of small patent ductus arteriosus (PDAs). Wave intensity analysis and wave energy flux was calculated using aortic pressure waveforms and echocardiography aortic Doppler measurements as previously described. Significant differences were seen in the peak forward compression wave (p = 0.013), early systolic energy flux (p = 0.005) and the systolic and diastolic ratio (p = 0.006) in Fontan patients versus controls. Within the Fontan group, there was a positive correlation (0.54, p = 0.02) between the wave speed and pulmonary vascular resistance. Early systolic energy flux was a potential individual indicator of a Fontan patients heart failure classification (AUC = 0.71). Wave intensity analysis could be a useful tool in screening Fontan patients and predicting clinical outcomes and Fontan failure. Future prospective analyses of Fontan hemodynamics and WIA are needed.

Predictive Models for Pulmonary Artery Size in Fontan Patients.

We developed models of pulmonary artery (PA) size in Fontan patients as a function of age and body surface area (BSA) using linear regression and breakpoint analyses based on data from 43 Fontan patients divided into two groups: the extracardiac conduit (ECC) group (n = 24) and the non-ECC group (n = 19). Model predictions were compared against those of a non-Fontan control group (n = 18) and published literature. We observed strong positive correlations of the mean PA diameter with BSA (r = 0.9, p < 0.05) and age (r = 0.88, p < 0.05) in the ECC group. The absolute percentage differences between our BSA and age model predictions against published literature were less than 16% and 20%, respectively. Predicted PA size for Fontan patients was consistently smaller than the control group. These models may serve as useful references for clinicians and be utilized to construct 3D anatomic models that correspond to patient body size or age.

Assessment of functional capacity among students with univentricular heart. / Evaluación de la capacidad funcional en escolares con fisiología de corazón univentricular.

A cross-sectional study was done in students with univentricular heart after undergoing total cavopulmonary connection (Fontan procedure) to establish their baseline functional capacity based on the six-minute walk test and identify potential determining factors. Thirty patients were included; their median age was 12 years old. Eighteen patients were males. The median distance walked was 551.3 meters, 84 % of the theoretical distance for a healthy pediatric population. Height, pre-test systolic blood pressure, and resting arterial oxygen saturation showed a significant association with the distance walked in the multiple linear regression model. No significant association was observed in the meters walked in terms of the following outcome measures: sex, nutritional status, baseline cardiological diagnosis, number of prior surgeries, and age at the time of Fontan procedure.

Se realizó un estudio transversal en escolares con corazón univentricular en estadio pos-bypass total de ventrículo derecho con el objetivo de determinar la capacidad funcional basal mediante el test de marcha en 6 minutos e identificar posibles factores determinantes. Participaron 30 pacientes con una mediana de edad de 12 años. Dieciocho pacientes fueron de sexo masculino. La mediana de distancia recorrida fue de 551,3 metros, un 84 % de la distancia teórica para población pediátrica sana. Las variables talla, presión arterial sistólica pretest y saturación arterial de oxígeno de reposo se asociaron significativamente con la distancia recorrida en el modelo de regresión lineal múltiple. No hubo asociación significativa en los metros caminados respecto de las variables sexo, estado nutricional, dignóstico cardiológico inicial, número de cirugías previas y edad al momento del bypass total de ventrículo derecho.

The Influence of Atrial Strain on Functional Capacity in Patients with the Fontan Circulation.

Speckle-tracking echocardiography has been used to assess atrial function. This analysis is feasible in univentricular hearts. The aim of this study was to characterize the relationship between atrial strain and functional capacity in the Fontan circulation. Apical four-chamber echocardiographic loops of 39 Fontan patients were reviewed. The dominant atrium was assessed for active (εact), conduit (εcon), and reservoir (εres) strain and εact/εres ratio. Cardiopulmonary exercise test was performed on the same day and oxygen uptake (VO2) at ventilatory threshold (VT) and peak VO2 were chosen as the dependent variables. Statistical analysis was performed using SPSS® version 23. Unpaired t test was used for binomial and continuous variable correlation; single and multivariable linear regression were used for continuous variable correlation. Statistical significance was defined as p value < 0.05. VO2 at VT as a percentage of predicted VO2 was 36.8% (SD 10.7). Peak VO2 was 64.7% (SD 18.9) of the predicted value. In univariate analysis, both were associated with age, atrioventricular regurgitation, ejection fraction, εres, εcon, and εact/εres. In multivariate regression, higher VO2 at VT and peak VO2 were associated with younger age (p = 0.003 and p = 0.001, respectively) and higher εcon (p = 0.026 and p = 0.020). Evaluation of heart function is difficult in the Fontan circulation, hindered by complex ventricular morphology and lack of normative data. VO2 provides a good surrogate. Atrial strain parameters are compromised in these patients and associated with VO2. Therefore, whenever possible, atrial strain should be measured as it may provide a new method of risk stratification.

A case of COVID-19 in a patient with a univentricular heart post total cavopulmonary connection (Fontan) surgery.

Coronavirus disease 2019 (COVID-19) has caused a global pandemic which has affected patients and healthcare systems around the world. Patients with underlying health conditions seem to be more severely affected. There are limited reports of patients with univentricular circulations and COVID 19; thus, we report a case of COVID-19 in a patient with a univentricular circulation.

Maternal Predictors of Disparate Outcomes in Children With Single Ventricle Congenital Heart Disease.

Background Significant variability in morbidity and mortality persists for children with functionally single ventricle congenital heart disease (SV-CHD) despite standardization in medical and surgical care. We hypothesized that maternal health factors may be associated with an increased risk of poor outcomes in children with SV-CHD. Methods and Results This retrospective, observational, cohort study included term maternal-infant pairs with a diagnosis of SV-CHD who underwent surgical palliation from 2006 to 2015 at Primary Children's Hospital. Pairs lacking maternal variables of interest or infant follow-up data were excluded. The association of maternal risk factors of abnormal pre-pregnancy body mass index, abnormal gestational weight gain (<7 or >20 kg), hypertensive disorders, and gestational diabetes mellitus with death/transplant and hemodynamics were analyzed using regression models. Of 190 infants, 135 (71%) maternal-infant dyads had complete data for inclusion. Death or transplant occurred in 48 infants (36%) during an average follow-up of 2.2 years (0.1-11.7 years). Abnormal gestational weight gain was associated with an increased risk of death and/or transplant in logistic regression (odds ratio, 3.22; 95% CI, 1.32-7.86; P=0.01), but not Cox regression (hazard ratio, 1.9; 95% CI, 1.0-3.7; P=0.055). Mean pulmonary artery pressures were higher in the setting of abnormal gestational weight gain (16.5±2.9 versus 14.7±3.0 mm Hg; P<0.001), and abnormal pre-pregnancy body mass index (15.7±3.5 versus 14.2±2.1 mm Hg; P<0.001) in the systemic right ventricle group. Conclusions Abnormal gestational weight gain (excessive or inadequate) is a novel risk factor for worse outcomes in SV-CHD. The fetoplacental environment may alter the trajectory of vascular development to impact outcomes in infants with SV-CHD.

Atrioventricular Valve Regurgitation in Single Ventricle Heart Disease: A Common Problem Associated With Progressive Deterioration and Mortality.

The Fontan procedure has provided patients with single ventricle physiology extended survival into adulthood and in many cases has improved their quality of life. Atrioventricular valve regurgitation (AVVR) is common in single ventricle patients and is associated with increased risk of mortality. AVVR is more common in patients with a systemic tricuspid or common atrioventricular valve but is generally progressive irrespective of underlying valve morphology. AVVR can be attributable to diverse structural and functional abnormalities at multiple levels of the valvar apparatus, as well as ventricular dysfunction and dilation. Multiple imaging modalities including recent advances in 3-dimensional echocardiography and cross-sectional imaging have been used to further understand AVVR. Surgery to address AVVR must be tailored to the underlying mechanism and the timing of surgical repair should be chosen carefully. In this review, we discuss the etiologies, treatment options, surgical timing, and outcomes of valve repair or replacement for AVVR in patients with single ventricle congenital heart disease, with a focus on those with a Fontan circulation as AVVR is associated with increased risk for Fontan failure and mortality. In-depth understanding of the current literature will help guide clinicians in their approach and management of AVVR in this population.

Red Blood Cell Transfusion After Stage I Palliation Is Associated With Worse Clinical Outcomes.

Background Packed red blood cell transfusion may improve oxygen content in single-ventricle neonates, but its effect on clinical outcomes after Stage 1 palliation is unknown. Methods and Results Retrospective multicenter analysis of packed red blood cell transfusion exposures in neonates after Stage 1 palliation, excluding those with intraoperative mortality or need for extracorporeal membrane oxygenation. Transfusion practice variability was assessed, and multivariable regression used to identify transfusion risk factors. After propensity score adjustment for severity of illness, clinical outcomes were compared between transfused and nontransfused subjects. Of 396 subjects, 323 (82%) received 930 postoperative red blood cell transfusions. Packed red blood cell volume (median 9-42 mL/kg [P<0.0001]), donor exposures (1-2 [P<0.0001]), transfusion number (1-3 [P<0.0001]), and pretransfusion hemoglobin (12.1-13 g/dL, P=0.0049) varied between sites. Cyanosis (P=0.02), chest tube output (P=0.0003), and delayed sternal closure (P=0.0033) increased transfusion risk. Transfusion was associated with prolonged mechanical ventilation (6 [interquartile range 4, 12] versus 3 [1, 5] days, P=0.02) and intensive care unit stay (19 [12, 33] versus 9 [6, 19] days, P=0.016). When stratified by number of transfusions (0, 1, or >1), duration of mechanical ventilation (3 [1, 5] versus 4 [3, 6] versus 9 [5, 16] days [P<0.0001]) and intensive care unit stay (9 [6, 19] versus 13 [8, 25] versus 21 [13, 38] days [P<0.0001]) increased for those transfused more than once. Most subjects who died were transfused, though the association with mortality was not significant. Conclusions Packed red blood cell transfusion after Stage 1 palliation is common, and transfusion practice is variable. Transfusion is a significant predictor of longer intensive care unit stay and mechanical ventilation. Further studies to define evidence-based transfusion thresholds are warranted.

Major aortopulmonary collateral arteries in a case of unrepaired tricuspid and pulmonary atresia with single ventricle physiology.

Tricuspid and pulmonary atresia with single ventricle physiology and major aortopulmonary collateral arteries (MAPCAs) is a complex cyanotic congenital heart disease with heterogeneous pulmonary artery morphology and arborization. The complex anatomy and physiology, coupled with a dearth of existing literature, pose imitable challenges to treatment. Although the exact surgical algorithm is still unclear, the goal is a well-developed, low-resistance pulmonary vascular bed. A precise understanding of the blood supply to each lung is a requisite for successful surgery, and a multimodality and multidisciplinary approach is compulsory. Herein, we describe a case of tricuspid and pulmonary atresia with single ventricle, MAPCAs and aortopulmonary collateral arteries.

What have we learnt 50 years after the first Fontan procedure?

The Fontan procedure is often the only definitive palliative surgical option for patients with a variety of complex CHD sharing in common, a single, dominant ventricle. In recent decades, imaging and therapeutic improvement have played a crucial role in those patients in whom many complications can hamper their life. After 50 years from the first procedure, heart transplantation remains the only definitive treatment for those with a failing Fontan circulation.