Surgical and Catheter-Based Reinterventions Are Common in Long-Term Survivors of the Fontan Operation

The effect of the conduit size on middle-term outcomes in patients with extracardiac total cavopulmonary connection

OBJECTIVES

The 18- and 16-mm conduits in extracardiac total cavopulmonary connection (eTCPC) were reported to be optimal based on energy loss and flow stagnation at the relatively early phase. However, because the artificial conduit lacks growth potential, we have recently encountered some cases in which the conduit needs to be changed several years after eTCPC. These cases prompted us to reconsider the surgical strategy for eTCPC.

METHODS

We reviewed our 20-year single-centre experience with eTCPC patients (n = 256) to compare the 18-mm conduit (n = 195) and 16-mm conduit (n = 61) in terms of mortality and morbidity.

RESULTS

The 16-mm conduit was used significantly more frequently in patients whose main chamber was right ventricle (P < 0.001). There was also a significant difference in preoperative inferior vena cava pressure (P = 0.008). There was a significant difference in the actuarial rate of freedom from late-occurring complications, including mortality, between the 2 groups (P = 0.003). There was a significant difference in the actuarial rate of reoperation-free survival (P = 0.042); however, there was no significant difference in resurgical intervention for the conduit (P = 0.333). In multivariate analysis, preoperative inferior vena cava pressure was an independent predictor for late-occurring complications (hazard ratio 1.19; P = 0.026). Conduit size (18 or 16 mm) itself was not an independent predictive factor for late-occurring complications (P = 0.690).

CONCLUSIONS

The mid-term clinical outcomes in patients who underwent eTCPC were excellent with low mortality. Preoperative inferior vena cava pressure was the only predictive risk factor for postoperative morbidity, and the 16 mm conduit was not predictive thereof.

The Fontan Udenafil Exercise Longitudinal Trial: Subgroup Analysis

The Pediatric Heart Network's Fontan Udenafil Exercise Longitudinal (FUEL) Trial (Mezzion Pharma Co. Ltd., NCT02741115) demonstrated improvements in some measures of exercise capacity and in the myocardial performance index following 6 months of treatment with udenafil (87.5 mg twice daily). In this post hoc analysis, we evaluate whether subgroups within the population experienced a differential effect on exercise performance in response to treatment. The effect of udenafil on exercise was evaluated within subgroups defined by baseline characteristics, including peak oxygen consumption (VO2), serum brain-type natriuretic peptide level, weight, race, gender, and ventricular morphology. Differences among subgroups were evaluated using ANCOVA modeling with fixed factors for treatment arm and subgroup and the interaction between treatment arm and subgroup. Within-subgroup analyses demonstrated trends toward quantitative improvements in peak VO2, work rate at the ventilatory anaerobic threshold (VAT), VO2 at VAT, and ventilatory efficiency (VE/VCO2) for those randomized to udenafil compared to placebo in nearly all subgroups. There was no identified differential response to udenafil based on baseline peak VO2, baseline BNP level, weight, race and ethnicity, gender, or ventricular morphology, although participants in the lowest tertile of baseline peak VO2 trended toward larger improvements. The absence of a differential response across subgroups in response to treatment with udenafil suggests that the treatment benefit may not be restricted to specific sub-populations. Further work is warranted to confirm the potential benefit of udenafil and to evaluate the long-term tolerability and safety of treatment and to determine the impact of udenafil on the development of other morbidities related to the Fontan circulation.Trial Registration NCT0274115.

Impact of Ventricular Dominance on Long-Term Fontan Outcomes: A 25-year Single-institution Study

BACKGROUND

The long-term impact of ventricular dominance on Fontan outcomes is controversial. This study examined this issue in a 25-year cohort.

METHODS

Patients undergoing the Fontan operation at a single institution (Duke University Medical Center, Durham, NC) from October 1998 to February 2022 were reviewed. Primary outcomes were transplant-free survival and Fontan failure (death, heart transplantation, takedown, protein-losing enteropathy, or plastic bronchitis). Secondary outcomes included hospital and intensive care lengths of stay. Kaplan-Meier methodology compared outcomes by ventricular dominance. Multiphase parametric risk hazard analysis identified risk factors for primary outcomes.

RESULTS

There were 195 patients (104 right ventricular dominant) included in the study. Baseline characteristics were comparable. Perioperative survival was similar (right ventricular dominant, 98%; non-right ventricular dominant, 100%; P = .51). The proportion of patients experiencing death or heart transplantation was 8.7%, and the rate of Fontan failure was 11.8% during a median follow-up of 4.5 years (interquartile range, 0.3-9.8 years). Right ventricular-dominant patients had reduced transplant-free survival (10-year estimates: 80% [95% CI, 70%-91%] vs 92% [95% CI, 83%-100%]; P = .04) and freedom from Fontan failure (73% [95% CI, 62%-86%] vs 92% [95% CI, 83%-100%]; P = .04). Multiphase hazard modeling resolved 2 risk phases. The early phase spanned from surgery to approximately 6 months afterward. The late phase spanned from approximately 6 months after surgery onward. In multivariable analysis, right ventricular dominance was an independent risk factor for death or heart transplantation (parameter estimate, 1.3 ± 0.6; P = .04) and Fontan failure (1.1 ± 0.5; P = .04) during the second phase, with no significant first-phase risk factors.

CONCLUSIONS

Right ventricular dominance was associated with long-term complications after Fontan procedures, including mortality, heart transplantation, and Fontan failure. This cohort may benefit from heightened surveillance in a multidisciplinary Fontan clinic after the perioperative period.

Variation in hospital costs and resource utilisation after congenital heart surgery

BACKGROUND

Children undergoing cardiac surgery have overall improving survival, though they consume substantial resources. Nationwide inpatient cost estimates and costs at longitudinal follow-up are lacking.

METHODS

Retrospective cohort study of children <19 years of age admitted to Pediatric Health Information System administrative database with an International Classification of Diseases diagnosis code undergoing cardiac surgery. Patients were grouped into neonates (≤30 days of age), infants (31-365 days of age), and children (>1 year) at index procedure. Primary and secondary outcomes included hospital stay and hospital costs at index surgical admission and 1- and 5-year follow-up.

RESULTS

Of the 99,670 cohort patients, neonates comprised 27% and had the highest total hospital costs, though daily hospital costs were lower. Mortality declined (5.6% in 2004 versus 2.5% in 2015, p < 0.0001) while inpatient costs rose (5% increase/year, p < 0.0001). Neonates had greater index diagnosis complexity, greater inpatient costs, required the greatest ICU resources, pharmacotherapy, and respiratory therapy. We found no relationship between hospital surgical volume, mortality, and hospital costs. Neonates had higher cumulative hospital costs at 1- and 5-year follow-up compared to infants and children.

CONCLUSIONS

Inpatient hospital costs rose during the study period, driven primarily by longer stay. Neonates had greater complexity index diagnosis, required greater hospital resources, and have higher hospital costs at 1 and 5 years compared to older children. Surgical volume and in-hospital mortality were not associated with costs. Further analyses comprising merged clinical and administrative data are necessary to identify longer stay and cost drivers after paediatric cardiac surgery.

Location matters: Offset in tissue-engineered vascular graft implantation location affects wall shear stress in porcine models

Objective

Although surgical simulation using computational fluid dynamics has advanced, little is known about the accuracy of cardiac surgical procedures after patient-specific design. We evaluated the effects of discrepancies in location for patient-specific simulation and actual implantation on hemodynamic performance of patient-specific tissue-engineered vascular grafts (TEVGs) in porcine models.

Methods

Magnetic resonance angiography and 4-dimensional (4D) flow data were acquired in porcine models (n = 11) to create individualized TEVGs. Graft shapes were optimized and manufactured by electrospinning bioresorbable material onto a metal mandrel. TEVGs were implanted 1 or 3 months postimaging, and postoperative magnetic resonance angiography and 4D flow data were obtained and segmented. Displacement between intended and observed TEVG position was determined through center of mass analysis. Hemodynamic data were obtained from 4D flow analysis. Displacement and hemodynamic data were compared using linear regression.

Results

Patient-specific TEVGs were displaced between 1 and 8 mm during implantation compared with their surgically simulated, intended locations. Greater offset between intended and observed position correlated with greater wall shear stress (WSS) in postoperative vasculature (P < .01). Grafts that were implanted closer to their intended locations showed decreased WSS.

Conclusions

Patient-specific TEVGs are designed for precise locations to help optimize hemodynamic performance. However, if TEVGs were implanted far from their intended location, worse WSS was observed. This underscores the importance of not only patient-specific design but also precision-guided implantation to optimize hemodynamics in cardiac surgery and increase reproducibility of surgical simulation.

Canadian Cardiovascular Society 2022 Guidelines for Cardiovascular Interventions in Adults With Congenital Heart Disease

Interventions in adults with congenital heart disease (ACHD) focus on surgical and percutaneous interventions in light of rapidly evolving ACHD clinical practice. To bring rigour to our process and amplify the cumulative nature of evidence ACHD care we used the ADAPTE process; we systematically adjudicated, updated, and adapted existing guidelines by Canadian, American, and European cardiac societies from 2010 to 2020. We applied this to interventions related to right and left ventricular outflow obstruction, tetralogy of Fallot, coarctation, aortopathy associated with bicuspid aortic valve, atrioventricular canal defects, Ebstein anomaly, complete and congenitally corrected transposition, and patients with the Fontan operation. In addition to tables indexed to evidence, clinical flow diagrams are included for each lesion to facilitate a practical approach to clinical decision-making. Excluded are recommendations for pacemakers, defibrillators, and arrhythmia-directed interventions covered in separate designated documents. Similarly, where overlap occurs with other guidelines for valvular interventions, reference is made to parallel publications. There is a paucity of high-level quality of evidence in the form of randomized clinical trials to support guidelines in ACHD. We accounted for this in the wording of the strength of recommendations put forth by our national and international experts. As data grow on long-term follow-up, we expect that the evidence driving clinical practice will become increasingly granular. These recommendations are meant to be used to guide dialogue between clinicians, interventional cardiologists, surgeons, and patients making complex decisions relative to ACHD interventions.

Troubled Judging of Bronchus Compression Due to Contrast-Filled Balloon in Three-Dimensional Rotational Angiography

Three-dimensional rotational angiography (3DRA) is a suitable technique to detect the risk of left main bronchus (LMB) compression during left pulmonary artery (LPA) stenting in partial cavopulmonary connection and total cavopulmonary connection (TCPC). We report on a case of a 4-year-old boy with hypoplastic left heart syndrome and TCPC in which 3DRA and bronchoscopy gave conflicting information on airway patency during balloon interrogation. The balloon with high contrast concentration created a severe artifact impeding visibility of the LMB. Simultaneous flexible bronchoscopy revealed an unobstructed LMB. Repeated 3DRAs with lower contrast concentration had no artifact and showed a patent airway in accordance with the bronchoscopy. Conventional LPA stenting was performed without indication for stent ovalization. The benefit of low contrast concentration in the interrogation balloon was demonstrated in a second case of an 11-year-old boy with TCPC. The margins of the LPA and LMB were clearly visible without blank-out artifact. Oval stent procedure was necessary to prevent LMB compression. When 3DRA is used for vessel-airway interrogation, the balloon contrast concentration should be low in order to avoid artifacts. When in doubt, simultaneous flexible bronchoscopy can overcome the dilemma in airway judgment.

Invasive Hemodynamic Evaluation of the Fontan Circulation: Current Day Practice and Limitations

PURPOSE OF REVIEW

Establishing the Fontan circulation has led to improved survival in patients born with complex congenital heart diseases. Despite early success, the long-term course of Fontan patients is complicated by multi-organ dysfunction, mainly due to a combination of low resting and blunted exercise-augmented cardiac output as well as elevated central venous (Fontan) pressure. Similarly, despite absolute hemodynamic differences compared to the normal population with biventricular circulation, the "normal" ranges of hemodynamic parameters specific to age-appropriate Fontan circulation have not been well defined. With the ever-increasing population of patients requiring Fontan correction, it is of utmost importance that an acceptable range of hemodynamics in this highly complex patient cohort is better defined.

RECENT FINDINGS

Multiple publications have described hemodynamic limitations and potential management options in patients with Fontan circulation; however, an acceptable range of hemodynamic parameters in this patient population has not been well defined. Identification of "normal" hemodynamic parameters among patients with Fontan circulation will allow physicians to more objectively define indications for intervention, which is a necessary first step to eliminate institutional and regional heterogeneity in Fontan management and potentially improve long-term clinical outcomes.

The Epidemiology of Persons Living with Fontan in 2020 and Projections for 2030: Development of an Epidemiology Model Providing Multinational Estimates

Introduction

Fontan surgery is a palliative procedure performed in children with a functionally univentricular heart. Improvements in surgical technique over the past 30 years have increased life expectancy in this rare population. However, the epidemiology of persons living with Fontan is poorly understood. This study aimed to estimate the 2020 and 2030 prevalence of persons living with a Fontan circulation in 11 countries across the US, Europe, Australia and New Zealand, by procedure type: [atriopulmonary connection (AP), lateral tunnel total cavopulmonary connection (LT-TCPC) or extracardiac total cavopulmonary connection (EC-TCPC)]; and age group: [children (< 12 years), adolescents (12–17 years), and adults (≥ 18 years old)] by building an epidemiologic model.

Methods

The annual number of Fontan surgeries by country in 2010–2020 were extracted from hospital or claims databases, via procedure codes. The epidemiology of persons living with Fontan was modelled by applying these surgery frequencies to mid-year populations from 1972 to 2020 and overlaying an uptake curve. A literature search identified: 30-day mortality rates, long-term survival, and median age at surgery. Averages of these estimates were inputted into the model to project prevalence in 2030.

Results

The number of persons living with Fontan in 2020 across the 11 countries was estimated to be 47,881 [66 people per million (ppm)], rising to 59,777 (79 ppm) by 2030. In 2020, this population was 55% adults, 17% adolescents and 28% children shifting to 64%, 13% and 23%, respectively, in 2030. Among all persons living with Fontan, 74%/18%/9% are estimated to have EC-TCPC/LT-TCPC/AP, respectively, in 2020, and 83%/14%/4% in 2030.

Conclusions

According to this epidemiology model, the Fontan population is growing, partly driven by increased survival rates with the more recent LT-TCPC and EC-TCPC procedures (compared with AP). The 2020/2030 prevalence of persons living with Fontan is 66/79 ppm.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-02002-3.

Prevalent pharmacotherapy of US Fontan survivors: A study utilizing data from the MarketScan Commercial and Medicaid claims databases

BACKGROUND

Survivors of Fontan palliation are at life-long risk of thrombosis, arrhythmia, and circulatory failure. To our knowledge, no studies have evaluated current United States pharmaceutical prescription practice in this population.

METHODS

A retrospective observational study evaluating the prevalent use of prescription medications in children and adolescents with hypoplastic left heart syndrome or tricuspid atresia after Fontan completion (identified using ICD9/10 codes) was performed using data contained in the MarketScan Commercial and Medicaid databases for the years 2013 through 2018. Cardiac pharmaceuticals were divided by class. Anticoagulant agents other than platelet inhibitors, which are not uniformly a prescription medication, were also studied. Associations between increasing age and the likelihood of a filled prescription for each class of drug were evaluated. Annualized retail costs of pharmaceutical regimens were calculated.

RESULTS

A cohort of 4,056 subjects (median age 12 years [interquartile range: 8-16], 61% male, 60% commercial insurance) was identified. Of the cohort, 50% received no prescription medications. Angiotensin converting enzyme inhibitors/angiotensin receptor blockers (ACEi/ARB) (38%), diuretics (15%), and mineralocorticoid receptor antagonists (8%) were prescribed with the highest frequency. Pulmonary vasodilators were received by 6% of subjects. Older age was associated with increased likelihood of filled prescriptions for anticoagulants (P = .008), antiarrhythmic agents, digoxin, ACEi/ARB, and beta blockers (each P < .0001), but also lower likelihood of filled prescriptions for pulmonary vasodilators, conventional diuretics (both P < .0001), and mineralocorticoid receptor antagonists (P = .02).

CONCLUSIONS

Pharmaceuticals typically used to treat heart failure and pulmonary hypertension are the most commonly prescribed medications following Fontan palliation. While the likelihood of treatment with a particular class of medication is associated with the age of the patient, determining the optimal regimen for individual patients and the population at large is an important knowledge gap for future research.

Impairments in Pulmonary Function in Fontan Patients: Their Causes and Consequences

Patients with a Fontan circulation lack a sub-pulmonary ventricle with pulmonary blood flow passively redirected to the lungs. In the Fontan circulation, ventilation has a significant influence on pulmonary blood flow and cardiac output both at rest and with exercise. Children and adults with a Fontan circulation have abnormalities in lung function. In particular, restrictive ventilatory patterns, as measured by spirometry, and impaired gas transfer, as measured by the diffusing capacity of carbon monoxide, have been frequently observed. These abnormalities in lung function are associated with reduced exercise capacity and quality of life. Moderate to severe impairment in lung volumes is independently associated with reduced survival in adults with congenital heart disease. Skeletal and inspiratory muscle weakness has also been reported in patients with a Fontan circulation, with the prospect of improving respiratory muscle function through exercise training programs. In this review, we will present data on cardiopulmonary interactions in the Fontan circulation, the prevalence and severity of impaired lung function, and respiratory muscle function in this population. We will discuss potential causes for and consequence of respiratory impairments, and their impact on exercise capacity and longer-term Fontan outcome. We aim to shed light on possible strategies to reduce morbidity by improving respiratory function in this growing population of patients.

Neurodevelopmental and Mental Health Outcomes in Patients With Fontan Circulation: A State-of-the-Art Review

Children, adolescents and adults living with Fontan circulation face numerous neurological and developmental challenges. As the population with complex CHD increases thanks to outstanding improvement in medical and surgical care, the long-term developmental and mental health sequelae have become a public health priority in pediatric and congenital cardiology. Many patients with a Fontan circulation experience difficulty in areas of cognition related to attention and executive functioning, visual spatial reasoning and psychosocial development. They are also at high risk for mental health morbidities, particularly anxiety disorders and depression. Several hemodynamic risk factors, beginning during the fetal period, may influence outcomes and yield to abnormal brain growth and development. Brain injury such as white matter lesions, stroke or hemorrhage can occur before, during, or after surgery. Other sociodemographic and surgical risk factors such as multiple catheterizations and surgeries and prolonged hospital stay play a detrimental role in patients' neurodevelopmental prognosis. Prevention and intervention to optimize long-term outcomes are critical in the care of this vulnerable population with complex CHD.

Interventional Planning for Endovascular Revision of a Lateral Tunnel Fontan: A Patient-Specific Computational Analysis

Introduction

A 2-year-old female with hypoplastic left heart syndrome (HLHS)-variant, a complex congenital heart defect (CHD) characterized by the underdevelopment of the left ventricle, presented with complications following single ventricle palliation. Diagnostic work-up revealed elevated Fontan pathway pressures, as well as significant dilation of the inferior Fontan pathway with inefficient swirling flow and hepatic venous reflux. Due to the frail condition of the patient, the clinical team considered an endovascular revision of the Fontan pathway. In this work, we performed a computational fluid dynamics (CFD) analysis informed by data on anatomy, flow, and pressure to investigate the hemodynamic effect of the endovascular Fontan revision.

Methods

A patient-specific anatomical model of the Fontan pathway was constructed from magnetic resonance imaging (MRI) data using the cardiovascular modeling software CardiovasculaR Integrated Modeling and SimulatiON (CRIMSON). We first created and calibrated a pre-intervention 3D-0D multi-scale model of the patient’s circulation using fluid-structure interaction (FSI) analyses and custom lumped parameter models (LPMs), including the Fontan pathway, the single ventricle, arterial and venous systemic, and pulmonary circulations. Model parameters were iteratively tuned until simulation results matched clinical data on flow and pressure. Following calibration of the pre-intervention model, a custom bifurcated endograft was introduced into the anatomical model to virtually assess post-intervention hemodynamics.

Results

The pre-intervention model successfully reproduced the clinical hemodynamic data on regional flow splits, pressures, and hepatic venous reflux. The proposed endovascular repair model revealed increases of mean and pulse pressure at the inferior vena cava (IVC) of 6 and 29%, respectively. Inflows at the superior vena cava (SVC) and IVC were each reduced by 5%, whereas outflows at the left pulmonary artery (LPA) and right pulmonary artery (RPA) increased by 4%. Hepatic venous reflux increased by 6%.

Conclusion

Our computational analysis indicated that the proposed endovascular revision would lead to unfavorable hemodynamic conditions. For these reasons, the clinical team decided to forgo the proposed endovascular repair and to reassess the management of this patient. This study confirms the relevance of CFD modeling as a beneficial tool in surgical planning for single ventricle CHD patients.

Non-invasive Imaging in the Evaluation of Cardiac Shunts for Interventional Closure

Multimodality imaging provides important information to guide patient selection and pre-procedural decision making for shunt lesions in CHD. While echocardiography, CT, and CMR are well-established, 3D printing and now virtual reality imaging are beginning to show promise.

Biventricular Conversion in Unseptatable Hearts: "Ventricular Switch"

Patients with complex systemic and pulmonary venous anatomy, common atrioventricular canal defects and conotruncal anomalies have traditionally been routed to univentricular palliation and labeled as "unseptatable." This report describes our initial experience in septation/biventricular conversion ("ventricular switch"), utilizing the left ventricle (LV) as the subpulmonary ventricle, essentially recapitulating the physiology of congenitally corrected transposition of the great arteries. Five consecutive patients with challenging anatomic configuration underwent septation. All patients were severely cyanotic and had important functional limitations. All patients required complex atrial septation. Ventricular septation was precluded by fixed pulmonary vascular resistance in 2 patients. Systemic venous return was diverted to the morphologic LV as part of physiological 2V (n = 4) or 1.5 V repair (n = 1). Median conversion age was 9 years (range 11 months-46 years). Four patients had 12 previous cardiac surgical procedures in preparation for univentricular repair elsewhere. Three dimensional-printed heart models evaluated feasibility of septation. All patients are alive at a median follow-up of 0.6 years (range 0.08-2.7 years). Median hospital stay was 13 (range 10-60) days. LV recruitment improved functional status and significantly increased systemic oxygen saturation in all patients (79 ± 7% vs 95 ± 5%, P = 0.003). We report a novel paradigm for successfully utilizing both ventricles with the morphologic LV as the subpulmonary ventricle, in a complex population thought to be unseptatable. This approach is versatile and can likely be extrapolated to other complex anatomic configurations. Although we utilized this strategy in patients of variable age, earlier ventricular switch may yield the best results.

The Evolving Surgical Burden of Fontan Failure: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND

Fontan failure often requires surgical therapy in the form of Fontan revision or heart transplantation. We sought to characterize national trends in the surgical burden of Fontan failure and identify risk factors for adverse outcomes.

METHODS

Fontan patients undergoing Fontan revision or transplantation from January 2010 to June 2018 were included. We evaluated baseline characteristics and outcomes and used multivariable logistic regression to identify risk factors for operative mortality and composite mortality and major morbidity.

RESULTS

A total of 1135 patients underwent Fontan revision (n = 598) or transplantation (n = 537) at 100 centers. Transplantations increased from 34 in 2010 to 76 in 2017, largely owing to an increase in patients with hypoplastic left heart syndrome (HLHS) (18 in 2010 to 49 in 2017), while Fontan revision decreased (75 in 2010 to 49 in 2017). Transplantation patients were younger (median 14 years of age vs 18 years of age; P < .001), more often had preoperative risk factors (66% vs 40%; P < .001), and more often had HLHS (51% vs 15%; P < .001). Operative mortality and composite major morbidity and mortality were 7.6% and 35% for transplantation and 7.1% and 22% for Fontan revision, respectively. Multivariable risk factors for mortality included older age (odds ratio [OR], 1.08/y; P = .007), presence of preoperative risk factors (OR, 3.33; P = .002), and concomitant pulmonary artery reconstruction (OR, 2.7; P = .029) for Fontan revision but only older age (OR, 1.06/y; P = .020) for transplantation.

CONCLUSIONS

Both transplantation and Fontan revision are associated with high morbidity and mortality. There has been evolution of practices in surgical therapy for Fontan failure, perhaps related to rising prevalence of HLHS staged palliation.

Prevalence and Cause of Early Fontan Complications: Does the Lymphatic Circulation Play a Role?

Background

Recent studies suggest that lymphatic congestion plays a role in development of late Fontan complications, such as protein‐losing enteropathy. However, the role of the lymphatic circulation in early post‐Fontan outcomes is not well defined.

Methods and Results

This was a retrospective, single‐center study of patients undergoing first‐time Fontan completion from 2012 to 2017. The primary outcome was early Fontan complication ≤6 months after surgery, a composite of death, Fontan takedown, extracorporeal membrane oxygenation, chest tube drainage >14 days, cardiac catheterization, readmission, or transplant. Complication causes were assigned to 1 of 4 groups: (1) Fontan circuit obstruction, (2) ventricular dysfunction or atrioventricular valve regurgitation, (3) persistent pleural effusions in the absence of Fontan obstruction or ventricular dysfunction, and (4) chylothorax or plastic bronchitis. T2‐weighted magnetic resonance imaging sequences were used to assess for lymphatic perfusion abnormality. The cohort consisted of 238 patients. Fifty‐eight (24%) developed early complications: 20 of 58 (34.5%) in group 1, 8 of 58 (14%) in group 2, 18 of 58 (31%) in group 3, and 12 of 58 (20%) in group 4. Preoperative T2 imaging was available for 126 (53%) patients. Patients with high‐grade lymphatic abnormalities had 6 times greater odds of developing early complications (P=0.001).

Conclusions

There is substantial morbidity in the early post‐Fontan period. Half of those who developed early complications had lymphatic failure or persistent effusions unrelated to structural or functional abnormalities. Preoperative T2 imaging demonstrated that patients with higher‐grade lymphatic perfusion abnormalities were significantly more likely to develop early complications. This has implications for risk stratification and optimization of patients before Fontan palliation.

Routine Surveillance Catheterization is Useful in Guiding Management of Stable Fontan Patients

We developed a Fontan surveillance catheterization protocol as part of routine assessment of stable patients 10 years after Fontan completion. The surveillance catherization includes hemodynamic assessment with inhaled nitric oxide, angiography, liver biopsy, and transcatheter intervention if indicated. We aimed to describe hemodynamic and liver biopsy findings, response to pulmonary vasoreactivity testing, rates of transcatheter intervention, and changes in medical therapy following surveillance catheterization in stable Fontan patients. A single-center retrospective review of Fontan patients undergoing surveillance catheterization between November 2014 and May 2019 was performed. Liver biopsies were independently scored by two pathologists. Sixty-three patients underwent surveillance catheterization (mean age 14.6 ± 3.0 years). The mean Fontan pressure was 11.8 ± 2.1 mmHg. The mean cardiac index was 2.9 ± 0.6 L/min/m². In the 51 patients who underwent pulmonary vasoreactivity testing, there was a significant decrease in median pulmonary vascular resistance (1.8 [range 0.8-4.1] vs 1.4 [range 0.7-3.0] Wood units × m²; p < 0.001). The mean cardiac index increased (3.0 ± 0.6 vs 3.2 ± 0.7 L/min/m², p = 0.009). The Fontan pressure did not change significantly. Fifty-seven patients underwent liver biopsy, and all but one showed fibrosis. Nineteen patients (33.3%) demonstrated bridging fibrosis or cirrhosis. Twenty-five patients underwent 34 transcatheter interventions. Pulmonary artery or Fontan stent placement was performed in 19 patients. Phosphodiesterase type 5 inhibitors were initiated in nine patients following surveillance catheterization. Routine surveillance catheterization with liver biopsy in adolescent Fontan patients reveals information that can guide interventional and medical management. Further long-term follow-up and assessment are indicated to assess the benefit of these interventions.

Oval stenting in left pulmonary artery stenosis: a novel double balloon technique to prevent airway compression in single ventricle

AIMS

Left pulmonary artery (LPA) stenosis is common in patients with cavopulmonary connections. Stent implantation is the treatment of choice but may be complicated or contraindicated by left main bronchus (LMB) compression due to limited retro-aortic space after a Damus-Kaye-Stansel (DKS) or Norwood operation. This study describes a novel double balloon technique of LPA stenting in patients at risk of LMB compression.

METHODS AND RESULTS

A cohort study was performed in 11 patients who underwent LPA stenting with an oval stent technique between 2015 and 2018. Retro-aortic anatomy was evaluated periprocedurally by three-dimensional rotational angiography (3DRA). Pre-existing LMB compression was demonstrated by 3DRA in seven out of eight patients who had undergone previous LPA stenting and in one patient without stenting. Primary ovalisation with immediate stent implantation on double balloons was performed in one patient. Ten patients had secondary ovalisation with single balloon stent implantation followed by the double balloon technique for ovalisation. The procedures were successful in all patients and guaranteed LMB patency without increasing pre-existing compression.

CONCLUSIONS

The 3DRA-guided oval stent technique with double balloon inflation is successful in treating LPA stenosis after a DKS or Norwood operation in patients at risk of bronchial compression, guaranteeing LMB patency without increasing pre-existing compression.

In vivo implantation of 3-dimensional printed customized branched tissue engineered vascular graft in a porcine model

BACKGROUND

The customized vascular graft offers the potential to simplify the surgical procedure, optimize physiological function, and reduce morbidity and mortality. This experiment evaluated the feasibility of a flow dynamic-optimized branched tissue engineered vascular graft (TEVG) customized based on medical imaging and manufactured by 3-dimensional (3D) printing for a porcine model.

METHODS

We acquired magnetic resonance angiography and 4-dimensional flow data for the native anatomy of the pigs (n = 2) to design a custom-made branched vascular graft of the pulmonary bifurcation. An optimal shape of the branched vascular graft was designed using a computer-aided design system informed by computational flow dynamics analysis. We manufactured and implanted the graft for pulmonary artery (PA) reconstruction in the porcine model. The graft was explanted at 4 weeks after implantation for further evaluation.

RESULTS

The custom-made branched PA graft had a wall shear stress and pressure drop (PD) from the main PA to the branch PA comparable to the native vessel. At the end point, magnetic resonance imaging revealed comparable left/right pulmonary blood flow balance. PD from main PA to branch between before and after the graft implantation was unchanged. Immunohistochemistry showed evidence of endothelization and smooth muscle layer formation without calcification of the graft.

CONCLUSIONS

Our animal model demonstrates the feasibility of designing and implanting image-guided, 3D-printed, customized grafts. These grafts can be designed to optimize both anatomic fit and hemodynamic properties. This study demonstrates the tremendous potential structural and physiological advantages of customized TEVGs in cardiac surgery.

Reintervention and survival in 1428 patients in the Australian and New Zealand Fontan Registry

Objective

Patients undergoing single-ventricle palliation have experienced significant improvement in survival in the recent era. However, a substantial proportion of these patients undergo reoperations. We performed a review of the Australia and New Zealand (ANZ) Fontan Registry to determine the overall reintervention and reoperative burden in these patients.

Methods

A retrospective longitudinal cohort study was performed using data from patients who underwent a Fontan operation between 1975 and 2016 from the ANZ Fontan Registry. The data obtained included Fontan operation, reinterventions and most recent follow-up status. We examined the type and timing of reinterventions and survival.

Results

Of the 1428 patients identified, 435 (30%) underwent at least one reintervention after the Fontan operation: 110 patients underwent early reintervention and 413 underwent late reinterventions. Excluding Fontan conversion and transplantation, 220 patients underwent at least one interventional procedure and 209 patients underwent at least one reoperation. Fenestration closure and pacemaker-related procedures were the most common catheter and surgical interventions, respectively. The cumulative incidence of reintervention following Fontan was 23%, 37% and 55% at 10, 20 and 30 years, respectively. Survival and freedom from failure were worse in patients requiring later reintervention after Fontan surgery (51% vs 83% and 42% vs 69%, respectively at 30 years, p<0.001). This difference persisted after excluding pacemaker-related procedures (p<0.001). Operative mortality for non-pacemaker late reoperations after Fontan was 6%.

Conclusions

A substantial proportion of Fontan patients require further intervention to maintain effective single-ventricle circulation. Patients undergoing reoperation after Fontan have higher rates of mortality and failure, despite intervention.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

State of the art of the Fontan strategy for treatment of univentricular heart disease

In patients with a functionally univentricular heart, the Fontan strategy achieves separation of the systemic and pulmonary circulation and reduction of ventricular volume overload. Contemporary modifications of surgical techniques have significantly improved survival. However, the resulting Fontan physiology is associated with high morbidity. In this review, we discuss the state of the art of the Fontan strategy by assessing survival and risk factors for mortality. Complications of the Fontan circulation, such as cardiac arrhythmia, thromboembolism, and protein-losing enteropathy, are discussed. Common surgical and catheter-based interventions following Fontan completion are outlined. We describe functional status measurements such as quality of life and developmental outcomes in the contemporary Fontan patient. The current role of drug therapy in the Fontan patient is explored. Furthermore, we assess the current use and outcomes of mechanical circulatory support in the Fontan circulation and novel surgical innovations. Despite large improvements in outcomes for contemporary Fontan patients, a large burden of disease exists in this patient population. Continued efforts to improve outcomes are warranted. Several remaining challenges in the Fontan field are outlined.

Toward a patient-specific tissue engineered vascular graft

Integrating three-dimensional printing with the creation of tissue-engineered vascular grafts could provide a readily available, patient-specific, autologous tissue source that could significantly improve outcomes in newborns with congenital heart disease. Here, we present the recent case of a candidate for our tissue-engineered vascular graft clinical trial deemed ineligible due to complex anatomical requirements and consider the application of three-dimensional printing technologies for a patient-specific graft. We 3D-printed a closed-disposable seeding device and validated that it performed equivalently to the traditional open seeding technique using ovine bone marrow–derived mononuclear cells. Next, our candidate’s preoperative imaging was reviewed to propose a patient-specific graft. A seeding apparatus was then designed to accommodate the custom graft and 3D-printed on a commodity fused deposition modeler. This exploratory feasibility study represents an important proof of concept advancing progress toward a rationally designed patient-specific tissue-engineered vascular graft for clinical application.