Quantification of ventricular stress in univentricular hearts during early childhood using age-independent zlog-NT-proBNP

BACKGROUND

Children with univentricular hearts (UVH) undergo up to three palliative surgical procedures to achieve complete circulatory separation (Fontan circulation). As a marker of cardiac wall stress, NT-proBNP is a promising tool to assess systemic ventricular load in these patients. However, different reference intervals (RI) apply to each stage, as NT-proBNP is highly age-dependent.

METHODS

Children undergoing systemic-to-pulmonary (SP) shunt placement (stage 1), bidirectional cavopulmonary shunt (BCPS, stage 2) or total cavopulmonary connection (TCPC, stage 3) between 2011 and 2021 with NT-proBNP measurement within 7 days before surgery were included. Furthermore, outpatients after TCPC with NT-proBNP measurement were enrolled. Biomarker levels were evaluated using its age-adjusted z-score ("zlog-NT-proBNP"; age-independent RI, -1.96 to +1.96), allowing comparison between different stages and revealing changes in systemic ventricular load independent of the marked physiological decline in RI with age.

RESULTS

Overall, 289 children (227 before, 62 after TCPC) met the eligibility criteria. Median time between blood sampling and surgery (SP shunt/BCPS/TCPC) was 2 [1-3] days and 3.2 [2.0-4.5] years after TCPC. Age-adjusted zlog-NT-proBNP levels were 3.47 [2.79-3.93] in children with native UVH (before SP shunt), 3.10 [1.89-3.58] at stage 1 (before BCPS), 1.08 [0.51-1.88] at stage 2 (before TCPC), and 1.09 [0.72-1.75] at stage 3 (after TCPC/Fontan completion). Consequently, BCPS revealed the strongest decrease (median - 2.02 logarithmized standard deviations, p < 0.001).

CONCLUSIONS

In children with UVH undergoing staged Fontan palliation, zlog-NT-proBNP is a highly promising tool for course assessment of systemic ventricular load, independent of the age-related decline in physiological NT-proBNP concentration.

The Lifesaving Impact of Transcatheter Interventions in the Early Post-Fontan Palliation Period

Despite advancements in postoperative outcomes after Fontan surgery, there remains a risk of suboptimal outcomes and significant morbidity in the early postoperative period. Anatomical obstructions in the Fontan pathway can lead to prolonged pleural effusion or ascites, cyanosis, and low cardiac output syndrome (LCOS). Transcatheter interventions offer an alternative to early re-surgery for treating these complications. Over a 13-year period, early catheter angiography, performed within 30 days post-index procedure, was administered to 41 patients, identifying anatomical issues that necessitated re-intervention in 39 cases. This led to transcatheter interventions in 37 (10.4%) of the 344 Fontan surgery patients. The median age was 4.8 years (IQR: 4-9.4), and the median weight was 16.5 kg (IQR: 15-25.2), with females comprising 51.4% (19/37) of this group. The primary indications for the procedures were persistent pleural effusion or ascites in 27 patients (66%), LCOS in 8 patients (20%), and cyanosis in 6 patients (14%). Among the 37 undergoing transcatheter intervention, 30 were treated solely with this method and discharged, three died in ICU follow-up, and four required early re-surgery. No procedural mortality was observed. Our findings demonstrate that transcatheter interventions, including stent implantation, balloon angioplasty, and fenestration dilation, are safe and effective in the early post-Fontan period. Therefore, they should be considered an integral part of the management strategy for this patient group.

Prognostic Value of RV Function Analysis During the Interstage Period in Patients with Hypoplastic Left Heart Syndrome

Cardiac dysfunction is associated with mortality in children with hypoplastic left heart syndrome (HLHS). We evaluated the ability of qualitative and quantitative RV functional parameters to predict outcomes in HLHS patients. In this retrospective, single-center study, echocardiograms from 3 timepoints (pre-stage 1 palliation, 4-8 weeks post-stage 1 palliation, and pre-Glenn) were analyzed in infants with HLHS. Patients were stratified into two groups based on outcome of transplant-free survival post-Glenn (survivors) versus mortality or transplantation prior to Fontan (non-survivors). Images were retrospectively reviewed to obtain RV global longitudinal strain (RVGLS), RV-free wall strain (RVFWS), fractional area change (FAC), tricuspid annular systolic plane excursion (TAPSE), tissue motion annular displacement of the tricuspid valve (TMAD-TV) and qualitative systolic function assessment during the predetermined timepoints. An equal variance t-test and chi-square were used to determine significant differences and ROC curve analysis was performed to derive optimal cutoff values to predict mortality/transplant. A total of 47 patients met inclusion criteria, of which, 21 patients met composite endpoint. There were no significant differences in any RV functional parameter during the pre- or post-stage 1 palliation timepoints. The absolute values of RVFWS, RVGLS, and TMAD-TV were significantly greater in survivors than non-survivors during the pre-Glenn timepoint. A pre-Glenn RVGLS > -15.6 (AUC 0.79), RVFWS > -18.6 (AUC 0.75), and TMAD-TV < 12.6% (AUC 0.82) were sensitive and specific for predicting death or need for transplantation prior to Fontan completion. RVGLS, RVFWS, and TMAD-TV may help identify higher-risk HLHS patients during the interstage period.

Impact of 4D-Flow CMR Parameters on Functional Evaluation of Fontan Circulation

We sought to evaluate the potential clinical role of 4D-flow cardiac magnetic resonance (CMR)-derived energetics and flow parameters in a cohort of patients' post-Fontan palliation. In patients with Fontan circulation who underwent 4D-Flow CMR, streamlines distribution was evaluated, as well a 4D-flow CMR-derived energetics parameters as kinetic energy (KE) and energy loss (EL) normalized by volume. EL/KE index as a marker of flow efficiency was also calculated. Cardiopulmonary exercise test (CPET) was also performed in a subgroup of patients. The population study included 55 patients (mean age 22 ± 11 years). The analysis of the streamlines revealed a preferential distribution of the right superior vena cava flow for the right pulmonary artery (62.5 ± 35.4%) and a mild preferential flow for the left pulmonary artery (52.3 ± 40.6%) of the inferior vena cave-pulmonary arteries (IVC-PA) conduit. Patients with heart failure (HF) presented lower IVC/PA-conduit flow (0.75 ± 0.5 vs 1.3 ± 0.5 l/min/m2, p = 0.004) and a higher mean flow-jet angle of the IVC-PA conduit (39.2 ± 22.8 vs 15.2 ± 8.9, p < 0.001) than the remaining patients. EL/KE index correlates inversely with VO2/kg/min: R: - 0.45, p = 0.01 peak, minute ventilation (VE) R: - 0.466, p < 0.01, maximal voluntary ventilation: R:0.44, p = 0.001 and positively with the physiological dead space to the tidal volume ratio (VD/VT) peak: R: 0.58, p < 0.01. From our data, lower blood flow in IVC/PA conduit and eccentric flow was associated with HF whereas higher EL/KE index was associated with reduced functional capacity and impaired lung function. Larger studies are needed to confirm our results and to further improve the prognostic role of the 4D-Flow CMR in this challenging population.

Impact of the Rudimentary Chamber on Outcomes in Fontan Patients

Background: We sought to evaluate the influence of the rudimentary ventricle on long-term outcomes after the Fontan operation, focusing on exercise capacity and cardiac performance. Methods: Between 1995 and 2021, 290 patients underwent a total cavopulmonary connection. "Two-ventricle" Fontan circulation was defined as a rudimentary ventricle >30% of the dominant ventricle or >50% of its predicted normal value. This cohort was compared with patients with single-ventricle Fontan circulation. The primary endpoint was Fontan failure, and the secondary endpoints were VO2 and cardiac catheterization data at ten years postoperatively. Results: The median follow-up after the Fontan operation was 7.9 years (interquartile range: 1.9-13.9). No significant difference was found in Fontan failure-free survival between the "two-ventricle" Fontan circulation group and the single-ventricle Fontan circulation group (83/91, 93% vs 156/199, 78%), respectively at 20 years; P = .11). No significant difference was found in VO2 or cardiac performance except cardiac index, with 2.9 (2.3-4.8) versus 2.5 (2.3-4.3) L/min/m2 (P = .047). Fifty-one patients in the "two-ventricle" Fontan circulation group were followed up for over ten years after the Fontan operation. In the subgroup analysis of this cohort, the rudimentary ventricular end-diastolic volume/dominant ventricular end-diastolic volume ratio showed a significant positive correlation with dominant ventricular end-diastolic pressure (r = 0.58 [95% CI 0.35-0.74], P = .002) and a significant negative correlation with VO2 (r = -0.61 [95% CI -0.80 to -0.28], P = .001). Conclusions: The rudimentary ventricle was not significantly associated with any clinical disadvantages regarding Fontan failure. However, a large rudimentary ventricle was significantly associated with higher end-diastolic pressure and lower exercise capacity.

Intracranial Pressure and Cerebral Hemodynamics in Infants Before and After Glenn Procedure

OBJECTIVES

This prospective cohort study aimed to investigate changes in intracranial pressure (ICP) and cerebral hemodynamics in infants with congenital heart disease undergoing the Glenn procedure, focusing on the relationship between superior vena cava pressure and estimated ICP.

DESIGN

A single-center prospective cohort study.

SETTING

The study was conducted in a cardiac center over 4 years (2019-2022).

PATIENTS

Twenty-seven infants with congenital heart disease scheduled for the Glenn procedure were included in the study, and detailed patient demographics and primary diagnoses were recorded.

INTERVENTIONS

Transcranial Doppler (TCD) ultrasound examinations were performed at three time points: baseline (preoperatively), postoperative while ventilated (within 24-48 hr), and at discharge. TCD parameters, blood pressure, and pulmonary artery pressure were measured.

MEASUREMENTS AND MAIN RESULTS

TCD parameters included systolic flow velocity, diastolic flow velocity (dFV), mean flow velocity (mFV), pulsatility index (PI), and resistance index. Estimated ICP and cerebral perfusion pressure (CPP) were calculated using established formulas. There was a significant postoperative increase in estimated ICP from 11 mm Hg (interquartile range [IQR], 10-16 mm Hg) to 15 mm Hg (IQR, 12-21 mm Hg) postoperatively (p = 0.002) with a trend toward higher CPP from 22 mm Hg (IQR, 14-30 mm Hg) to 28 mm Hg (IQR, 22-38 mm Hg) postoperatively (p = 0.1). TCD indices reflected alterations in cerebral hemodynamics, including decreased dFV and mFV and increased PI. Intracranial hemodynamics while on positive airway pressure and after extubation were similar.

CONCLUSIONS

Glenn procedure substantially increases estimated ICP while showing a trend toward higher CPP. These findings underscore the intricate interaction between venous pressure and cerebral hemodynamics in infants undergoing the Glenn procedure. They also highlight the remarkable complexity of cerebrovascular autoregulation in maintaining stable brain perfusion under these circumstances.

Surgical Considerations in Adult Congenital Heart Disease Heart Failure

Surgical intervention is often used in the management of heart failure in patients with adult congenital heart disease. This review addresses anatomic variations and complications due to prior surgical interventions, including sternal reentry, collateral vessels, and the neo-aortic root after the Damus-Kaye-Stansel procedure. Surgical considerations for systemic atrioventricular valvular surgery, Fontan revision, and advanced heart failure therapies including ventricular assist devices, heart transplant, and combined heart-liver transplant are discussed, with a focus on unique patient populations including those with systemic right ventricles and those with Fontan circulation.

Impact of calorie intake and weight gain after Norwood procedure on the outcome of stage II palliation

BACKGROUND

This study aimed to assess the impact of caloric intake and weight-for-age-Z-score after the Norwood procedure on the outcome of bidirectional cavopulmonary shunt.

METHODS

A total of 153 neonates who underwent the Norwood procedure between 2012 and 2020 were surveyed. Postoperative daily caloric intake and weight-for-age-Z-score up to five months were calculated, and their impact on outcome after bidirectional cavopulmonary shunt was analysed.

RESULTS

Median age and weight at the Norwood procedure were 9 days and 3.2 kg, respectively. Modified Blalock-Taussig shunt was used in 95 patients and right ventricle to pulmonary artery conduit in 58. Postoperatively, total caloric intake gradually increased, whereas weight-for-age-Z-score constantly decreased. Early and inter-stage mortality before stage II correlated with low caloric intake. Older age (p = 0.023) at Norwood, lower weight (p < 0.001) at Norwood, and longer intubation (p = 0.004) were correlated with low weight-for-age-Z-score (< -3.0) at 2 months of age. Patients with weight-for-age-Z-score < -3.0 at 2 months of age had lower survival after stage II compared to those with weight-for-age-Z-score of -3.0 or more (85.3 versus 92.9% at 3 years after stage II, p = 0.017). There was no difference between inter-stage weight gain and survival after bidirectional cavopulmonary shunt between the shunt types.

CONCLUSION

Weight-for-age-Z-score decreased continuously throughout the first 5 months after the Norwood procedure. Age and weight at Norwood and intubation time were associated with weight gain. Inter-stage low weight gain (Z-score < -3) was a risk for survival after stage II.

Contemporary transesophageal echocardiography practice patterns among paediatric cardiology centres in the United States and Canada

OBJECTIVE

To characterise transesophageal echocardiography practice patterns among paediatric cardiac surgical centres in the United States and Canada.

METHODS

A 42-question survey was sent to 80 echocardiography laboratory directors at paediatric cardiology centres with surgical programmes in the United States and Canada. Question domains included transesophageal echocardiography centre characteristics, performance and reporting, equipment use, trainee participation, and quality assurance.

RESULTS

Fifty of the 80 centres (62.5%) responded to the survey. Most settings were academic (86.0%) with 42.0% of centres performing > 350 surgical cases/year. The median number of transesophageal echocardiograms performed/cardiologist/year was 50 (26, 73). Pre-operative transesophageal echocardiography was performed in most surgical cases by 91.7% of centres. Transesophageal echocardiography was always performed by most centres following Norwood, Glenn, and Fontan procedures and by < 10% of centres following coarctation repair. Many centres with a written guideline allowed transesophageal echocardiography transducer use at weights below manufacturer recommendations (50.0 and 61.1% for neonatal and paediatric transducers, respectively). Most centres (36/37, 97.3%) with categorical fellowships had rotations which included transesophageal echocardiography participation. Large surgical centres (>350 cases/year) had higher median number of transesophageal echocardiograms/cardiologist/year (75.5 [53, 86] versus 35 [20, 52], p < 0.001) and more frequently used anaesthesia for diagnostic transesophageal echocardiography ≥ 67% of time (100.0 versus 62.1%, p = 0.001).

CONCLUSIONS

There is significant variability in transesophageal echocardiography practice patterns and training requirements among paediatric cardiology centres in the United States and Canada. Findings may help inform programmatic decisions regarding transesophageal echocardiography expectations, performance and reporting, equipment use, trainee involvement, and quality assurance.

Impact of Age-Related Change in Caval Flow Ratio on Hepatic Flow Distribution in the Fontan Circulation

BACKGROUND

The Fontan operation is a palliative technique for patients born with single ventricle heart disease. The superior vena cava (SVC), inferior vena cava (IVC), and hepatic veins are connected to the pulmonary arteries in a total cavopulmonary connection by an extracardiac conduit or a lateral tunnel connection. A balanced hepatic flow distribution (HFD) to both lungs is essential to prevent pulmonary arteriovenous malformations and cyanosis. HFD is highly dependent on the local hemodynamics. The effect of age-related changes in caval inflows on HFD was evaluated using cardiac magnetic resonance data and patient-specific computational fluid dynamics modeling.

METHODS

SVC and IVC flow from 414 patients with Fontan were collected to establish a relationship between SVC:IVC flow ratio and age. Computational fluid dynamics modeling was performed in 60 (30 extracardiac and 30 lateral tunnel) patient models to quantify the HFD that corresponded to patient ages of 3, 8, and 15 years, respectively.

RESULTS

SVC:IVC flow ratio inverted at ≈8 years of age, indicating a clear shift to lower body flow predominance. Our data showed that variation of HFD in response to age-related changes in caval inflows (SVC:IVC, 2, 1, and 0.5 corresponded to ages, 3, 8, and 15+, respectively) was not significant for extracardiac but statistically significant for lateral tunnel cohorts. For all 3 caval inflow ratios, a positive correlation existed between the IVC flow distribution to both the lungs and the HFD. However, as the SVC:IVC ratio changed from 2 to 0.5 (age, 3-15+) years, the correlation's strength decreased from 0.87 to 0.64, due to potential flow perturbation as IVC flow momentum increased.

CONCLUSIONS

Our analysis provided quantitative insights into the impact of the changing caval inflows on Fontan's long-term HFD, highlighting the importance of SVC:IVC variations over time on Fontan's long-term hemodynamics. These findings broaden our understanding of Fontan hemodynamics and patient outcomes.

Perioperative Evaluation of Arterial and Venous Whole Blood in the Lamb (Ovis aries) Fontan Model

Whole blood analysis can evaluate numerous parameters, including pH, pCO₂, pO₂, HCO₃ - , base excess, glucose, electrolytes, lactate, blood urea nitrogen, creatinine, bilirubin, and hemoglobin. This valuable tool enables clinicians to make more informed decisions about patient care. However, the current body of literature describing perioperative whole blood analysis in Dorset sheep (Ovis aries) is small, so clinicians lack adequate information to guide their decision-making when evaluating test results. We evaluated arterial and venous whole blood pH, bicarbonate, pCO₂, lactate, creatinine, and blood urea nitrogen before and for the first 24 hours after surgery in 2 cohorts of male and female Ovis arie s undergoing one of 2 major cardiovascular procedures, a Single-Stage Fontan or an inferior vena cava to pulmonary artery extracardiac conduit implantation (IP-ECC). The cohort undergoing a Single-Stage Fontan, which is the more complex procedure, exhibited greater deviation from baseline measurements than did the cohort undergoing the IP-ECC for lactate, bicarbonate, and creatinine. The cohort undergoing the IP-ECC showed no significant deviation from baseline for any parameters, potentially indicating a better safety margin than expected when compared with the Single-Stage Fontan. Together, these results indicate the clinical value of arterial and venous whole blood measurements in perioperative management of sheep and can provide a reference for clinicians managing sheep after significant cardiovascular procedures.

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.

In vitro hemodynamic performance of a blood pump for self-powered venous assist in univentricular hearts

Univentricular heart anomalies represent a group of severe congenital heart defects necessitating early surgical intervention in infancy. The Fontan procedure, the final stage of single-ventricle palliation, establishes a serial connection between systemic and pulmonary circulation by channeling venous return to the lungs. The absence of the subpulmonary ventricle in this peculiar circulation progressively eventuates in failure, primarily due to chronic elevation in inferior vena cava (IVC) pressure. This study experimentally validates the effectiveness of an intracorporeally-powered venous ejector pump (VEP) in reducing IVC pressure in Fontan patients. The VEP exploits a fraction of aortic flow to create a jet-venturi effect for the IVC, negating the external power requirement and driveline infections. An invitro Fontan mock-up circulation loop is developed and the impact of VEP design parameters and physiological conditions is assessed using both idealized and patient-specific total cavopulmonary connection (TCPC) phantoms. The VEP performance in reducing IVC pressure exhibited an inverse relationship with the cardiac output and extra-cardiac conduit (ECC) size and a proportional relationship with the transpulmonary pressure gradient (TPG) and mean arterial pressure (MAP). The ideal VEP with fail-safe features provided an IVC pressure drop of 1.82 ± 0.49, 2.45 ± 0.54, and 3.12 ± 0.43 mm Hg for TPG values of 6, 8, and 10 mm Hg, respectively, averaged over all ECC sizes and cardiac outputs. Furthermore, the arterial oxygen saturation was consistently maintained above 85% during full-assist mode. These results emphasize the potential utility of the VEP to mitigate elevated venous pressure in Fontan patients.

Long-Term Survival After Single-Ventricle Palliation: A Swedish Nationwide Cohort Study

BACKGROUND

Long-term survival after single-ventricle palliation and the effect of dominant ventricle morphology in large, unselected series of patients are scarcely reported.

METHODS AND RESULTS

This nationwide cohort study included all children undergoing operation with single-ventricle palliation during their first year of life in Sweden between January 1994 and December 2019. Data were obtained from institutional records and assessment of underlying cardiac anomaly and dominant ventricular morphology was based on complete review of medical records, surgical reports, and echocardiographic examinations. Data on vital status and date of death were retrieved from the Swedish Cause of Death Register, allowing for complete data on survival. Among 766 included patients, 333 patients (43.5%) were classified as having left or biventricular dominance, and 432 patients (56.4%) as having right ventricular (RV) dominance (of whom 231 patients had hypoplastic left heart syndrome). Follow-up was 98.7% complete (10 patients emigrated). Mean follow-up was 11.3 years (maximum, 26.7 years). Long-term survival was significantly higher in patients with left ventricular compared with RV dominance (10-year survival: 91.0% [95% CI, 87.3%-93.6%] versus 71.1% [95% CI, 66.4%-75.2%]). RV dominance had a significant impact on outcomes after first-stage palliation but was also associated with impaired survival after completed total cavopulmonary connection. In total, 34 (4.4%) patients underwent heart transplantation. Of these 34 patients, 25 (73.5%) had predominant RV morphology.

CONCLUSIONS

This study provides clinically relevant knowledge about the long-term prognosis in patients with different underlying cardiac anomalies undergoing single-ventricle palliation. RV dominance had a significant impact on outcomes after initial surgical treatment but was also associated with impaired survival after completed Fontan circulation.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03356574.

Leg-focused high-weight resistance training improves ventricular stroke volume, exercise capacity and strength in young patients with a Fontan circulation

AIMS

Effective therapy to improve exercise capacity in Fontan patients is lacking. Leg-focused high-weight resistance training might augment the peripheral muscle pump and thereby improve exercise capacity.

METHODS AND RESULTS

This randomized semi-cross-over controlled trial investigated the effects of a 12-week leg-focused high-weight resistance training plus high-protein diet, on (sub)maximal exercise capacity, cardiac function (assessed with cardiovascular magnetic resonance), muscle strength, and quality of life in paediatric Fontan patients. Twenty-eight paediatric Fontan patients were included, 27 patients, (median age 12.9 [10.5-15.7]), and successfully completed the programme. Peak oxygen uptake (PeakVO2) at baseline was reduced [33.3 mL/kg/min (27.1-37.4), 73% (62-79) of predicted]. After training PeakVO2/kg and Peak workload improved significantly with +6.2 mL/kg/min (95%CI: 3.4-9.0) (+18%) P < 0.001 and +22 Watts (95%CI: 12-32) (+18%) P < 0.001, respectively, compared to the control period. Indexed single ventricle stroke volume increased significantly [43 mL/beat/m2 (40-49) vs. 46 (41-53), P = 0.014], as did inferior vena cava flow [21 mL/beat/m2 (18-24) vs. 23 (20-28), P = 0.015], while superior vena cava flow remained unchanged. The strength of all measured leg-muscles increased significantly compared to the control period. Self-reported quality of life improved on the physical functioning and change in health domains of the child health questionnaire, parent-reported quality of life improved the bodily pain, general health perception, and change in health domains compared to the control period.

CONCLUSION

In a relatively large group of 27 older Fontan children, 12-weeks of leg-focused high-weight resistance training improved exercise capacity, stroke volume, (sub)maximal exercise capacity, muscle strength, and domains of quality of life.

REGISTRATION

International Clinical Trials: Trial NL8181.

Parental Impressions and Perspectives of Efficacy in Prenatal Counseling for Single Ventricle Congenital Heart Disease

Although commonly performed, optimal techniques, strategies, and content to achieve the most effective prenatal counseling have not been explored. We investigate the efficacy of prenatal counseling via survey feedback of parents of children with prenatally diagnosed single ventricle. Grades of counseling using a Likert scale (1-5) were solicited to assess: (1) overall impression of quantity of counseling, (2) explanation of the heart defect, (3) preparation for heart surgery, (4) preparation for hospital course and care, (5) preparation for complications and outcomes of a Fontan circulation, and (6) preparation for neurological, school-related, or behavioral problems. Impressions were solicited concerning specific providers. A comprehensive fetal counseling score was calculated for each participant. Burden of care including length of hospitalization was explored as impacting prenatal counseling grades. There were 59 survey respondents. Average age of the children at the time of survey was 4.6 ± 3.3 years (range 1-10 years). Highest grades were for explanation of the heart condition, with lowest grades for preparation for neurological, school-related, or behavioral problems. Cardiac surgeon received the highest with social worker lowest grade for provider. Negative correlation was found between the composite fetal counseling score and parental recollection of length of hospitalization (Pearson r = - 0.357, p < 0.01). Prenatal counseling for neurological, school-related, and behavioral problems in single ventricle is deficient. Further studies analyzing prenatal counseling techniques and content can help improve upon the delivery of this important aspect of prenatal care.

Perioperative Characteristics and Outcomes of Fontan Versus Non-Fontan Patients Undergoing Combined Heart-Liver Transplantation: A Retrospective Cohort Study

OBJECTIVES

Combined heart-liver transplantation (CHLT) is becoming increasingly frequent as a maturing population of patients with Fontan-palliated congenital heart disease develop advanced liver fibrosis or cirrhosis. The authors present their experience with CHLT for congenital and noncongenital indications, and identify characteristics associated with poor outcomes that may guide intervention in high-risk patients.

DESIGN

This was a single-center retrospective cohort study.

SETTING

This study was conducted at Vanderbilt University Medical Center in Nashville, Tennessee.

PARTICIPANTS

The study included 16 consecutive adult recipients of CHLT at the authors' institution between April 2017 and February 2022.

INTERVENTIONS

Eleven patients underwent transplantation for Fontan indications, and 5 were transplanted for non-Fontan indications.

MEASUREMENTS AND MAIN RESULTS

Compared with non-Fontan patients, Fontan recipients had longer cardiopulmonary bypass duration (199 v 119 minutes, p =m0.002), operative times (786 v 599 minutes, p = 0.01), and larger blood product transfusions (15.4 v 6.3 L, p = 0.18). Six of 16 patients required extracorporeal membrane oxygenation (ECMO), of whom 4 were Fontan patients who subsequently died. Patients who required ECMO had lower 5-hour lactate clearance (0.0 v 3.5 mmol/L, p = 0.001), higher number of vasoactive infusions, lower pulmonary artery pulsatility indices (0.58 v 1.77, p = 0.03), and higher peak inspiratory pressures (28.0 v 18.5 mmHg, p = 0.01) after liver reperfusion.

CONCLUSIONS

Combined heart-liver transplantation in patients with Fontan-associated end-organ disease is particularly challenging and associated with higher recipient morbidity compared with non-Fontan-related CHLT. Early hemodynamic intervention for signs of ventricular dysfunction may improve outcomes in this growing high-risk population.

Pulmonary artery coarctation repair in univentricular heart: indications and optimal timing

BACKGROUND

To analyse surgical outcomes of pulmonary artery coarctation in univentricular hearts, focusing on surgical indications and optimal timing.

METHODS

We retrospectively reviewed 49 patients with pulmonary artery coarctation in univentricular hearts treated at our institution between 1993 and 2022. Twenty-eight patients were diagnosed before first-stage palliation. Of these, 14 underwent systemic-pulmonary shunt only as first-stage palliation (Group 1), and 14 underwent systemic-pulmonary shunt plus surgical pulmonary artery plasty as first-stage palliation (Group 2). Twenty-one patients diagnosed after first-stage palliation underwent surgical pulmonary artery plasty at the time of bidirectional Glenn procedure (Group 3).

RESULTS

Follow-up period after initial palliation was 6±8 years. The Fontan procedure was successful in 35 patients (71%) aged 28±26 months (range 18-139). Freedom from interstage death (Group 1, 53%; Group 2, 85%; Group 3, 93%) and interstage reintervention (Group 1, 50%; Group 2, 75%; Group 3, 73%) rates were significantly lower in Group 1 (p = 0.01). Five and four patients in Group 1 and Group 3, respectively, needed additional shunts before the bidirectional Glenn procedure. In Group 1, one patient with a non-confluent pulmonary artery achieved hemi-lung Fontan circulation. In Group 2, one patient suffering with a non-confluent pulmonary artery could not achieve Fontan circulation, whereas another patient with pulmonary venous obstruction achieved hemi-lung Fontan circulation.

CONCLUSIONS

Surgical pulmonary artery plasty performed at first-stage palliation improved outcomes of pulmonary artery coarctation in univentricular hearts, particularly when pulmonary artery coarctation had already progressed during the neonatal period or early infancy.

Use of a modified microvascular plug to modify fenestration flow in a rapidly failing Fontan

We report a case of an alternative transcatheter use of the modified Medtronic microvascular plug to modify fenestration stent flow in a patient with a rapidly deteriorating clinical condition. This four-year-old boy developed severe cyanosis following fenestration stent insertion, initially placed due to prolonged drainage post-Fontan with extra-cardiac conduit. In April 2023, he underwent urgent cardiac catheterisation and had partial occlusion of fenestration stent with a modified 9Q microvascular plug. His oxygen saturations improved from 50 to 89% in room air with no re-emergence of raised cavopulmonary pressures.

Intrahepatic Transcriptomics Differentiate Advanced Fibrosis and Clinical Outcomes in Adults With Fontan Circulation

BACKGROUND

The molecular mechanisms underlying Fontan-associated liver disease (FALD) remain largely unknown.

OBJECTIVES

This study aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes.

METHODS

This retrospective cohort study included adults with the Fontan circulation. Baseline clinical, laboratory, imaging, and hemodynamic data as well as a composite clinical outcome (CCO) were extracted from medical records. Patients were classified into early or advanced fibrosis. RNA was isolated from formalin-fixed paraffin-embedded liver biopsy samples; RNA libraries were constructed with the use of an rRNA depletion method and sequenced on an Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were performed with the use of DESeq2 and Metascape.

RESULTS

A total of 106 patients (48% male, median age 31 years [IQR: 11.3 years]) were included. Those with advanced fibrosis had higher B-type natriuretic peptide levels and Fontan, mean pulmonary artery, and capillary wedge pressures. The CCO was present in 23 patients (22%) and was not predicted by advanced liver fibrosis, right ventricular morphology, presence of aortopulmonary collaterals, or Fontan pressures on multivariable analysis. Samples with advanced fibrosis had 228 upregulated genes compared with early fibrosis. Samples with the CCO had 894 upregulated genes compared with those without the CCO. A total of 136 upregulated genes were identified in both comparisons and were enriched in cellular response to cytokine stimulus or oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-β signaling pathway, and vasculature development.

CONCLUSIONS

Patients with FALD and advanced fibrosis or the CCO exhibited upregulated genes related to inflammation, congestion, and angiogenesis.

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

OBJECTIVE

To evaluate for correlation between exercise capacity as assessed by peak oxygen consumption (pVO2) measurement during a cardiopulmonary exercise test (CPET) and smartwatches reporting this parameter in patients with adult congenital heart disease (ACHD) complex lesions.

METHODS

A prospective study that included patients with ACHD either a Fontan circulation or a right ventricle supporting the systemic circulation who underwent two separate CPETs at least 1 year apart. Generalised estimating equations linear regression was performed to identify factors associated with correlation between smartwatch and CPET-derived pVO2.

RESULTS

48 patients (71% with a Fontan circulation, 42% females, mean age 33±9 years) underwent two CPETs between May 2018 and May 2022 with echocardiograms performed within 6 months of each CPET. Apple Watch was the predominant smartwatch used (79%). Smartwatch and CPET measured peak heart rate (Pearson correlation=0.932, 95% CI (0.899, 0.954)) and pVO2 (0.8627, 95% CI (0.8007, 0.9064) and 0.8634, 95% CI (0.7676, 0.9215) in the first and second CPET, respectively) correlated well, with smartwatch-measured pVO2 values measuring higher by a mean of 3.146 mL/kg/min (95% CI (2.559, 3.732)). Changes in pVO2 between the first and the second CPET also correlated well (Pearson correlation=0.9165, 95% CI (0.8549, 0.9525)), indicating that for every 1 mL/(min kg) change in CPET-measured pVO2, there was a corresponding 0.896 mL/(min kg) change in the smartwatch-measured pVO2.

CONCLUSION

Both absolute values and changes over time in pVO2 as measured by smartwatches and CPETs correlate well in patients with complex ACHD.

Nutritional considerations for people living with a Fontan circulation: a narrative review

The population of people living with a Fontan circulation are highly heterogenous, including both children and adults, who have complex health issues and comorbidities associated with their unique physiology throughout life. Research focused on nutritional considerations and interventions in the Fontan population is extremely limited beyond childhood. This review article discusses the current literature examining nutritional considerations in the setting of Fontan physiology and provides an overview of the available evidence to support nutritional management strategies and future research directions. Protein-losing enteropathy, growth deficits, bone mineral loss, and malabsorption are well-recognised nutritional concerns within this population, but increased adiposity, altered glucose metabolism, and skeletal muscle deficiency are also more recently identified issues. Emergencing evidence suggets that abnormal body composition is associated with poor circulatory function and health outcomes. Many nutrition-related issues, including the impact of congenital heart disease on nutritional status, factors contributing to altered body composition and comorbidities, as well as the role of the microbiome and metabolomics, remain poodly understood.

Superior cavopulmonary shunt via right vertical axillary mini-thoracotomy

We present 2 cases of patients with univentricular heart physiology of different anatomic variants who successfully underwent minimally invasive bidirectional cavopulmonary anastomosis via the right vertical axillary mini-thoracotomy.

Staged Ventricular Septation of the Double-Inlet Ventricle: How-I-Do-It

Ventricular septation of the double-inlet ventricle is a largely abandoned operation due to poor historical outcomes. However, there has been renewed interest in septation as an alternative to Fontan palliation given its long-term sequelae. As one of the few centers to revisit septation in the early 1990s, our institution has long-term data on a series of patients with a double-inlet ventricle who underwent biventricular repair. This manuscript is a summary of our approach to staged septation of the double-inlet ventricle, with a focus on patient selection criteria, surgical techniques, perioperative considerations on timing of interventions, and long-term results. We believe that septation of the double-inlet ventricle should be reconsidered in patients with suitable anatomy in light of the known complications of Fontan palliation.

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

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

Univentricular hearts not undergoing Fontan: the type of palliation matters

INTRODUCTION AND OBJECTIVES

There is scarce information on patients with single ventricle physiology (SVP) and restricted pulmonary flow not undergoing Fontan circulation. This study aimed to compare survival and cardiovascular events in these patients according to the type of palliation.

METHODS

SVP patient data were obtained from the databases of the adult congenital heart disease units of 7 centers. Patients completing Fontan circulation or developing Eisenmenger syndrome were excluded. Three groups were created according to the source of pulmonary flow: G1 (restrictive pulmonary forward flow), G2 (cavopulmonary shunt), and G3 (aortopulmonary shunts±cavopulmonary shunt). The primary endpoint was death.

RESULTS

We identified 120 patients. Mean age at the first visit was 32.2 years. Mean follow-up was 7.1 years. Fifty-five patients (45.8%) were assigned to G1, 30 (25%) to G2, and 35 (29.2%) to G3. Patients in G3 had worse renal function, functional class, and ejection fraction at the first visit and a more marked ejection fraction decline during follow-up, especially when compared with G1. Twenty-four patients (20%) died, 38 (31.7%) were admitted for heart failure, and 21 (17.5%) had atrial flutter/fibrillation during follow-up. These events were more frequent in G3 and significant differences were found compared with G1 in terms of death (HR, 2.9; 95%CI, 1.14-7.37; P=.026) and atrial flutter/fibrillation (HR, 2.9; 95%CI, 1.11-7.68; P=.037).

CONCLUSIONS

The type of palliation in patients with SVP and restricted pulmonary flow not undergoing Fontan palliation identifies distinct profiles. Patients palliated with aortopulmonary shunts have an overall worse prognosis with higher morbidity and mortality.

Associations of Liver Stiffness Measured by Ultrasound Shear-Wave Elastography With Portal Hypertension and Circulatory Failure in Individuals With Fontan Circulation

BACKGROUND. The Fontan operation palliates single-ventricle congenital heart disease but causes hepatic congestion with associated progressive hepatic fibrosis. OBJECTIVE. The purpose of this study was to evaluate associations between liver stiffness measured using ultrasound (US) shear-wave elastography (SWE) in patients with Fontan palliation and the occurrence of portal hypertension and Fontan circulatory failure during follow-up. METHODS. This retrospective study included 119 individuals 10 years old or older (median age, 19.1 years; 61 female patients, 58 male patients) with Fontan circulation who underwent liver US with 2D SWE from January 1, 2015, to January 1, 2022, and had 1 year or more of clinical follow-up (unless experiencing earlier outcome-related events). Median liver stiffness from the initial US examination was documented. Varices, ascites, splenomegaly, and thrombocytopenia (VAST) scores (range, 0-4) were determined as a marker of portal hypertension on initial US examination and 1 year or more of follow-up imaging (US, CT, or MRI). Composite clinical outcome for Fontan circulatory failure (death, mechanical circulatory support, cardiac transplant, or unexpected Fontan circulation-related hospitalization) was assessed. Analysis included the Wilcoxon rank sum test, logistic regression analysis with stepwise variable selection, and ROC analysis. RESULTS. Median initial liver stiffness was 2.22 m/s. Median initial VAST score was 0 (IQR, 0-1); median follow-up VAST score was 1 (IQR, 0-2) (p = .004). Fontan circulatory failure occurred in 37 of 119 (31%) patients (median follow-up, 3.4 years). Initial liver stiffness was higher in patients with a follow-up VAST score of 1 or greater (2.37 m/s) than in those with a follow-up VAST score of 0 (2.08 m/s) (p = .005), and initial liver stiffness was higher in patients with (2.43 m/s) than without (2.10 m/s) Fontan circulatory failure during follow-up (p < .001). Initial liver stiffness was the only significant independent predictor of Fontan circulatory failure (OR = 3.76; p < .001); age, sex, Fontan operation type, dominant ventricular morphology, and initial VAST score were not independent predictors. Initial liver stiffness had an AUC of 0.70 (sensitivity, 79%; specificity, 57%; threshold, > 2.11 m/s) for predicting a follow-up VAST score of 1 or greater and an AUC of 0.74 (sensitivity, 84%; specificity, 52%; threshold, > 2.12 m/s) for predicting Fontan circulatory failure. CONCLUSION. In patients with Fontan circulation, increased initial liver stiffness was associated with portal hypertension and circulatory failure during follow-up, although it had moderate performance in predicting these outcomes. CLINICAL IMPACT. US SWE may play a role in post-Fontan surveillance, supporting tailored medical and surgical care.

Management of Junctional Rhythm in Patients After the Fontan Operation: A Multicenter Congenital Cardiology Survey

Sinus node dysfunction with concomitant junctional rhythm (JR) is frequently observed among Fontan patients and has been recognized as a contributor to heart failure. The impact and management of JR is unclear. A survey was mailed to all members of the Pediatric and Congenital Electrophysiology society (PACES) and members were asked to forward the questionnaire to their non-electrophysiology colleagues. Responses were received from 154 physicians (88 electrophysiologists (EP's) and 66 non-EP's (46 pediatric cardiologists and 20 adult congenital cardiologists). There were few differences in the response between EP's and non-EP's. Overall, 57% recommended an annual ambulatory ECG (AECG). A significant majority (80%) opted to continue to follow patients with significant periods of JR on AECG as long as the patients were asymptomatic, and showed no echocardiographic signs of cardiac decompensation. However, 84% would place a pacemaker in a patient with JR who was having open chest surgery for other reasons. Finally, pacemaker placement would be performed by 91% if a patient with JR showed signs of heart failure. Most congenital cardiologists would not recommend pacemaker placement in asymptomatic Fontan patients with JR. Further studies are needed on the Fontan population to determine the impact of SND and JR on longer term outcomes and to determine the role and optimal timing of pacemaker placement in these patients.

Switching the Left and the Right Hearts: A Novel Bi-ventricle Mechanical Support Strategy with Spared Native Single-Ventricle

End-stage Fontan patients with single-ventricle (SV) circulation are often bridged-to-heart transplantation via mechanical circulatory support (MCS). Donor shortage and complexity of the SV physiology demand innovative MCS. In this paper, an out-of-the-box circulation concept, in which the left and right ventricles are switched with each other is introduced as a novel bi-ventricle MCS configuration for the "failing" Fontan patients. In the proposed configuration, the systemic circulation is maintained through a conventional mechanical ventricle assist device (VAD) while the venous circulation is delegated to the native SV. This approach spares the SV and puts it to a new use at the right-side providing the most-needed venous flow pulsatility to the failed Fontan circulation. To analyze its feasibility and performance, eight SV failure modes have been studied via an established multi-compartmental lumped parameter cardiovascular model (LPM). Here the LPM model is experimentally validated against the corresponding pulsatile mock-up flow loop measurements of a representative 15-year-old Fontan patient employing a clinically-approved VAD (Medtronic-HeartWare). The proposed surgical configuration maintained the healthy cardiac index (3-3.5 l/min/m2) and the normal mean systemic arterial pressure levels. For a failed SV with low ejection fraction (EF = 26%), representing a typical systemic Fontan failure, the proposed configuration enabled a ~ 28 mmHg amplitude in the venous/pulmonary waveforms and a 2 mmHg decrease in the central venous pressure (CVP) together with acceptable mean pulmonary artery pressures (17.5 mmHg). The pulmonary vascular resistance (PVR)-SV failure case provided a ~ 5 mmHg drop in the CVP, with venous/pulmonary pulsatility reaching to ~ 22 mmHg. For the high PVR failure case with a healthy SV (EF = 44%) pulmonary hypertension is likely to occur as expected. While this condition is routinely encountered during the heart transplantation and managed through pulmonary vasodilators a need for precise functional assessment of the spared failed-ventricle is recommended if utilized in the PVR failure mode. Comprehensive in vitro and in silico results encourage this novel concept as a low-cost, more physiological alternative to the conventional bi-ventricle MCS pending animal experiments.

Reintervention Before Bidirectional Cavopulmonary Shunt and Intermediate Outcomes in Children with Single Ventricle Who Underwent Main Pulmonary Artery Banding

Unplanned reinterventions following pulmonary artery banding (PAB) in single ventricle patients are common before stage 2 palliation (S2P) but associated risk factors are unknown. We hypothesized that reintervention is more common when PAB is placed at younger age and with a looser band, reflected by lower PAB pressure gradient. Retrospective single center study of single ventricle patients undergoing PAB between Jan 2000 and Dec 2020. The association with reintervention and successful S2P was modeled using exploratory cause-specific hazard regression. A multivariable model was developed adjusting for clinical and statistically relevant predictors. The cumulative proportion of patients undergoing reintervention were summarized using a competing risk model. 77 patients underwent PAB at median (IQR) 47 (24-66) days and 3.73 (3.2-4.5) kg. Within18 months of PAB, 60 (78%) reached S2P, 9 (12%) died, 1 (1%) transplanted and 7 (9%) were alive without S2P. Within 18 months of PAB 10 (13%) patients underwent reintervention related to pulmonary blood flow modification: PAB adjustment (n = 6) and conversion to Damus-Kaye-Stansel/Blalock-Taussig-Thomas shunt (n = 4). 6/10 (60%) reached S2P following reintervention. A trend toward higher intervention in patients with a genetic syndrome (p-0.06) and weight < 3 kg (p-0.057) at time of PAB was noted. Only genetic syndrome was a risk factor associated with poor outcome (p-0.025). PAB has a reasonable outcome in SV patients with unobstructed systemic and pulmonary blood flow, but with a high reintervention rate. Only a quarter of patients with genetic syndromes reach S2P and further study is required to explore the benefits from an alternative palliative strategy.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

Extra-cardiac and complex Fontan baffle fenestration using radio frequency current via surgical electrocautery

BACKGROUND

Fontan baffle punctures and creation of Fontan fenestration for cardiac catheterisation procedures remain challenging especially due to the heavy calcification of prosthetic material and complex anatomy.

OBJECTIVES

We sought to evaluate our experience using radiofrequency current via surgical electrocautery needle for Fontan baffle puncture to facilitate diagnostic, electrophysiology, and interventional procedures.

METHODS

A retrospective chart review of all Fontan patients (pts) who underwent Fontan baffle puncture using radiofrequency energy via surgical electrocautery from three centres were performed from January 2011 to July 2021.

RESULTS

A total of 19 pts underwent 22 successful Fontan baffle puncture. The median age and weight were 17 (3-36 years) and 55 (14-88) kg, respectively. The procedural indications for Fontan fenestration creation included: diagnostic study (n = 1), atrial septostomy and stenting (n = 1), electrophysiology study and ablation procedures (n = 8), Fontan baffle stenting for Fontan failure including protein-losing enteropathy (n = 7), and occlusion of veno-venous collaterals (n = 2) for cyanosis. The type of Fontan baffles included: extra-cardiac conduits (n = 12), lateral tunnel (n = 5), classic atrio-pulmonary connection (n = 1), and intra-cardiac baffle (n = 1). A Fontan baffle puncture was initially attempted using traditional method in 6 pts and Baylis radiofrequency trans-septal system in 2 pts unsuccessfully. In all pts, Fontan baffle puncture using radiofrequency energy via electrocautery needle was successful. The radiofrequency energy utilised was (10-50 W) and required 1-5 attempts for 2-5 seconds. There were no vascular or neurological complications.

CONCLUSIONS

Radiofrequency current delivery using surgical electrocautery facilitates Fontan baffle puncture in patients with complex and calcified Fontan baffles for diagnostic, interventional, and electrophysiology procedures.

Implications of attention and executive functioning weaknesses in youth with Fontan circulation

Youth with Fontan circulation (Fontan) are at-risk for impairments in attention and executive functioning (EF) due to a confluence of genetic, prenatal, surgical, and medical risk factors. We sought to describe attention and EF in this population, measured via standardized performance-based tests and caregiver rating scales. We then examined how weaknesses in attention and EF were related to outcomes in other neurobehavioral domains, including adaptive behavior and academic achievement. Our sample included 93 youth with Fontan who were referred for neuropsychological evaluations as part of standard clinical care. The cohort as a whole measured between 0.18 to 0.99 standard deviations below normative means across domains of attention, EF, academic achievement, and intellectual ability. In addition, caregiver-reported concerns for attention, EF, anxiety, and depression were elevated, and approximately 0.35 to 0.85 standard deviations above normative means. Lastly, caregiver-reported adaptive behavior measured 0.93 to 1.24 standard deviations below normative values. Academic outcomes were differentially affected by demographic and attention/EF variables, while depression and caregiver-reported EF predicted adaptive behavior. Findings from this study underscore the importance of routine neuropsychological evaluation as part of comprehensive, multidisciplinary care for individuals with Fontan, with the goal of enhancing neurobehavioral and functional outcomes across the lifespan.

In vivo hepatic flow distribution by computational fluid dynamics can predict pulmonary flow distribution in patients with Fontan circulation

In Fontan patients, a lung deprived of hepatic blood may develop pulmonary arterio-venous malformations (PAVMs) resulting in shunting, reduced pulmonary vascular resistance (PVR) and decreased oxygenation. To provide guidance for corrective invasive interventions, we aimed to non-invasively determine how the hepatic to pulmonary blood flow balance correlates with pulmonary flow, PVR, and with oxygen saturation. Magnetic resonance imaging (MRI) data from eighteen Fontan patients (eight females, age 3-14 years) was used to construct patient-specific computational fluid dynamics (CFD) models to calculate the hepatic to pulmonary blood flow. This was correlated with pulmonary vein flow, simulated PVR and oxygen saturation. Clinical applicability of the findings was demonstrated with an interventional patient case. The hepatic to pulmonary blood flow balance correlated with right/left pulmonary vein flow (R2 = 0.50), left/right simulated PVR (R2 = 0.47), and oxygen saturation at rest (R2 = 0.56). In the interventional patient, CFD predictions agreed with post-interventional MRI measurements and with regressions in the cohort. The balance of hepatic blood to the lungs has a continuous effect on PVR and oxygen saturation, even without PAVM diagnosis. MRI combined with CFD may help in planning of surgical and interventional designs affecting the hepatic to pulmonary blood flow balance in Fontan patients.

Outcomes After Hybrid Palliation for Infants With Critical Left Heart Obstruction

BACKGROUND

Hybrid palliation (bilateral pulmonary artery banding with or without ductal stenting) is an initial management strategy for infants with critical left heart obstruction and serves as palliation until subsequent operations are pursued.

OBJECTIVES

This study sought to determine patient characteristics and factors associated with subsequent outcomes for infants who underwent hybrid palliation.

METHODS

From 2005 to 2019, 214 of 1,236 prospectively enrolled infants within the Congenital Heart Surgeons' Society's critical left heart obstruction cohort underwent hybrid palliation across 24 institutions. Multivariable hazard modeling with competing risk methodology was performed to determine risk and factors associated with outcomes of biventricular repair, Fontan procedure, transplantation, or death.

RESULTS

Preoperative comorbidities (eg, prematurity, low birth weight, genetic syndrome) were identified in 70% of infants (150 of 214). Median follow-up was 7 years, ranging up to 17 years. Overall 12-year survival was 55%. At 5 years after hybrid palliation, 9% had biventricular repair, 36% had Fontan procedure, 12% had transplantation, 35% died without surgical endpoints, and 8% were alive without an endpoint. Factors associated with transplantation were absence of ductal stent, older age, absent interatrial communication, smaller aortic root size, larger tricuspid valve area z-score, and larger left ventricular volume. Factors associated with death were low birth weight, concomitant genetic syndrome, cardiopulmonary bypass use during hybrid palliation, moderate to severe tricuspid valve regurgitation, and smaller ascending aortic size.

CONCLUSIONS

Mortality remains high after hybrid palliation for infants with critical left heart obstruction. Nonetheless, hybrid palliation may facilitate biventricular repair for some infants and for others may serve as stabilization for intended functional univentricular palliation or primary transplantation.