The Fontan procedure for tricuspid atresia: early and late results of a 25-year experience with 216 patients

27 years of experience with the Fontan procedure: characteristics and clinical outcomes of children in a tertiary referral hospital

BACKGROUND

The Fontan operation has improved the survival of children born with congenital heart disease with single ventricle physiology. The most widely adopted variations of the Fontan procedure are the extracardiac conduit, the lateral tunnel ve the intra/extracardiac conduit with fenestration. Despite advances in the treatment and prevention of early and late complications that may develop after Fontan surgery, morbidity still remains an important problem.

METHODS

304 patients who underwent Fontan surgery in our center between 1995 and 2022 were included in our study. The complications that developed in patients who underwent primary Fontan or lateral tunnel surgery and extracardiac conduit Fontan application were compared.

RESULTS

Classic Fontan surgery and lateral tunnel surgery were performed in 26 of the patients, and extracardiac Fontan surgery was performed in 278 patients. 218 of 304 cases were patients with single ventricular pathology. 86 cases were patients with two ventricular morphologies but complex cardiac pathology. Fenestration was performed in only 6 patients, other patients did not require fenestration. The mean follow-up period of our patients was 12 years (3 months-27 years). When the complications between Fontan procedures were compared in our study, it was found that the length of hospital stay and mortality were statistically significantly reduced in patients who underwent extracardiac Fontan surgery. There was no significant difference in terms of complications that can be seen after Fontan surgery and the length of stay in the intensive care unit.

CONCLUSION

Fontan complex is a palliative surgery for children with complex heart disease. Palliative surgical operations aimed at the preparation of the Fontan circulation lead to the preparation of the pulmonary vascular bed and the preservation of ventricular function. The techniques applied in Fontan surgery affect the early and long-term complications and the survival of the patients. In our study, when we examined the patients who extracardiac conduit Fontan procedure for the non-cardiac route, we found that mortality and morbidity were minimal.

Acute Liver Failure due to Altered Fontan Circulation in a Patient With Tricuspid Atresia: A Case Report

Tricuspid atresia is a congenital malformation of the tricuspid valve resulting in a lack of blood flow between the right atrium and the right ventricle. Management generally involves staged surgical intervention enabling affected individuals to survive into adulthood. Although surgical intervention greatly improves morbidity and mortality in this patient population, there are many long-term complications associated with the creation of a surgical shunt. We report a case of a 33-year-old male with tricuspid atresia who underwent Fontan surgery as a child and presented to our hospital with acute liver failure.

Outcomes after the Fontan operation in the Middle East: A large Saudi Arabian single centre experience

BACKGROUND

Fontan outcomes data from large volume Middle Eastern Centres are lacking. We report our experience after the Fontan operation from a tertiary cardiac centre in Saudi Arabia.

METHOD

All 458 consecutive patients who had Fontan surgery 1986 through 2015 at the Prince Sultan Cardiac Centre, Riyadh [PSCC], Saudi Arabia, were evaluated for baseline, early and late post-operative outcomes and their uni and multivariate determinants.

RESULTS

The mean age at Fontan operation was 7 years [IQR 4.8-9.0]. The most common anatomic diagnoses were tricuspid atresia (104 [23%]) and double-inlet left ventricle (81 [18%]). Only 3 patients in the present series had hypoplastic left heart syndrome [HLHS]. Early mortality [i.e. during Fontan surgical admission] was 3.1%. At late follow-, 35 (8%) patients were lost to follow up. The 1, 5, 10, 20 and 30 year survival was 96%, 94%, 93% and 85%, respectively. In the modern surgical era, 5, 10 and 15 year survival were 96%, 95% and 93% respectively. Univariate determinants of death or transplant were hypoalbuminemia, elevated NtProBNP >500, surgical era prior to 1999, the lack of Fontan fenestration, and prior atriopulmonary Fontan [APF] procedure. On multivariate analysis, surgical era before 1999 and prior APF procedure were independently associated with death or transplant.

CONCLUSIONS

Fontan patients from this large volume Middle Eastern centre have comparable early and late mortality outcomes compared to prior published reports. Rigorous selection criteria at the time of Fontan, and Fontan specific dedicated care teams are likely contributors to this success.

The Adult Patient with a Fontan

The authors summarize the most important anatomic and physiologic substrates of Fontan circulation. Common anatomic substrates include hypoplastic left heart syndrome, tricuspid atresia, double inlet left ventricle, and unbalanced atrioventricular septal defects. After the Fontan operation exercise capacity is limited and the key hemodynamic drivers is limited preload due to a relatively fixed pulmonary vascular resistance. The authors provide contemporary data on survival, morbidity, and need for reintervention. Operative morality is now expected to be less than 1% and 30 year survival approximately 89%. The authors delineate potential therapeutic approaches for the potential late complications.

Prevalence of Short Stature and Growth Hormone Deficiency and Factors Associated With Short Stature After Fontan Surgery

Background: Fontan circulation is characterized by many features commonly observed in heart failure that may affect physical growth regardless of pituitary gland dysfunction status. The aims of the present study were to investigate the prevalence of short stature and growth hormone deficiency (GHD) and determine the factors associated with short stature after Fontan surgery.

Methods and Results: On retrospective evaluation of 47 patients after Fontan surgery, a very high prevalence of short stature was observed (38.3%). In the short stature group, 5 patients were diagnosed with GHD (10.6% of patients after Fontan Surgery), which is much higher than the frequency of 1/10,000 in the general population. Central venous pressure (CVP) was significantly higher (14.6±4.5 vs. 12.2±1.9 mmHg, P<0.05) and the blood pressure and arterial oxygen saturation were significantly lower in the short stature group. Laboratory data also indicated volume retention and congestion in the short stature group. Mean change in stature from catheterization 1 year after Fontan surgery to the most recent visit was significantly lower in the short stature group (−1.1±1.1 SD vs. 0.0±0.8 SD, P<0.05) and significantly negatively correlated with CVP (r=−0.42, P<0.05).

Conclusions: Volume retention and congestion, the prominent features of Fontan circulation, affect physical growth partly due to pituitary gland dysfunction, highlighting the need for the screening for and treatment of this condition after Fontan surgery.

Quantitative comparison of two-dimensional and three-dimensional strain measurement using MRI feature tracking in repair Fontan patients and normal child volunteers

BACKGROUND

The accuracy of 2D and 3D strain analyses was evaluated by comparing strain and cardiac function parameters in Fontan repair patients and normal child volunteers.

METHODS

We retrospectively enrolled 32 patients with Fontan circulation and 32 child volunteers who had undergone clinical cardiac magnetic resonance (CMR) assessment of the dominant ventricle with a 1.5-Tesla MRI scanner. Global and regional strain (2D and 3D) of the dominant ventricle in both groups was assessed using CMR feature-tracking. Correlations between cardiac function and strain data were assessed using Pearson's correlation coefficient values. The intraclass correlation coefficient (ICC) and coefficient of variation (CoV) were determined to evaluate repeatability and agreement.

RESULTS

The 2D GLS showed significant differences between the Fontan repair patients and volunteers (- 16.49 ± 5.00 vs. -19.49 ± 2.03; p = 0.002). The 2D GRS and 2D GCS showed no significant differences between two groups. 2D GRS: 38.96 ± 14.48 vs. 37.46 ± 7.77; 2D GCS: - 17.64 ± 5.00 vs. -16.89 ± 2.96, respectively; p > 0.05). The 3D global radial strain (GRS), global circumferential strain (GCS), and global longitudinal strain (GLS) showed significant differences between the Fontan repair patients and volunteers (3D GRS: 36.35 ± 16.72 vs. 44.96 ± 9.98; 3D GLS: - 8.86 ± 6.84 vs. -13.67 ± 2.44; 3D GCS: - 13.70 ± 7.84 vs. -18.01 ± 1.78; p < 0.05, respectively). The ejection fraction (EF) and 3D GCS were significantly associated (r = - 0.491, p = 0.004). The 3D GCS showed correlations with the indexed end-diastolic volume (EDV) (r = 0.523, p = 0.002) and indexed end-systolic volume (ESV) (r = 0.602, p < 0.001). 3D strain showed good reproducibility, with GCS showing the best inter-observer agreement (ICC = 0.87 and CoV = 5.15), followed by GLS (ICC = 0.84 and CoV = 5.36).

CONCLUSIONS

3D GCS is feasible, highly reproducible, and strongly correlated with conventional cardiac function measures. 3D GCS assessments may be useful for monitoring abnormal myocardial motion in patients with Fontan circulation.

Percutaneous liver biopsy in Fontan patients

BACKGROUND

Patients who have undergone the Fontan operation for palliation of congenital heart disease with single-ventricle pathophysiology are at high risk for developing progressive liver fibrosis. Pathological assessment from percutaneous liver biopsy is central to the management of Fontan-associated liver disease, but liver biopsy in this vulnerable population poses unique challenges and potential risks.

OBJECTIVE

This retrospective study describes our experience with percutaneous liver biopsy performed to assess changes of Fontan-associated liver disease, with particular regard to procedural outcomes.

MATERIALS AND METHODS

Data from liver biopsy procedure reports, pathology reports, cardiac angiography pressure measurements and laboratory values of patients with single ventricle heart disease after the Fontan operation who underwent ultrasound-guided percutaneous liver biopsy performed in interventional radiology at a pediatric tertiary care center during a 3-year period were retrospectively analyzed.

RESULTS

Sixty-eight liver biopsies were performed in 67 patients (mean age: 20.2 years, range: 7.2-39 years). The technical success rate was 100%, and tissue was adequate for assessing liver disease in 100% of the procedures, including biopsies performed with a single pass. Anticoagulation was routinely suspended before biopsy, and no cardiac complications were encountered due to this suspension. A coaxial biopsy system using an 18-gauge (G) full-core instrument through a 17-G introducer trocar was most commonly used, in 41/68 cases (60%). The most common trough length was 2.3 cm, used in 37 cases (54%). One pass was made in 27 procedures (40%) and two passes in 30 (44%); tract embolization with gelatin sponge was performed in 52 (76%). The only complication was hemorrhage, which occurred in 5/68 (7.4%) of the biopsies, minor in four (5.9%) and major in one (1.5%) -- similar to rates reported for liver biopsy in non-Fontan patients. Hemorrhage had a delayed presentation in three of these five cases. Immediate post-biopsy hemoglobin decrease of ≥2 mg/dL showed a low sensitivity for hemorrhage. The mean Fontan pressure measured during cardiac angiography was 13.8 mmHg, and shunt pressures were not associated with an increased risk of hemorrhage.

CONCLUSION

Percutaneous liver biopsy in Fontan patients can be performed safely with high technical success rates and without increased complication rates. Meticulous technique and close observation are recommended to reduce post-biopsy complications. The degree of right heart pressure elevation was not associated with hemorrhage.

In vitro validation of a self-driving aortic-turbine venous-assist device for Fontan patients

Background

Palliative repair of single ventricle defects involve a series of open-heart surgeries where a single-ventricle (Fontan) circulation is established. As the patient ages, this paradoxical circulation gradually fails, because of its high venous pressure levels. Reversal of the Fontan paradox requires an extra subpulmonic energy that can be provided through mechanical assist devices. The objective of this study was to evaluate the hemodynamic performance of a totally implantable integrated aortic-turbine venous-assist (iATVA) system, which does not need an external drive power and maintains low venous pressure chronically, for the Fontan circulation.

Methods

Blade designs of the co-rotating turbine and pump impellers were developed and 3 prototypes were manufactured. After verifying the single-ventricle physiology at a pulsatile in vitro circuit, the hemodynamic performance of the iATVA system was measured for pediatric and adult physiology, varying the aortic steal percentage and circuit configurations. The iATVA system was also tested at clinical off-design scenarios.

Results

The prototype iATVA devices operate at approximately 800 revolutions per minute and extract up to 10% systemic blood from the aorta to use this hydrodynamic energy to drive a blood turbine, which in turn drives a mixed-flow venous pump passively. By transferring part of the available energy from the single-ventricle outlet to the venous side, the iATVA system is able to generate up to approximately 5 mm Hg venous recovery while supplying the entire caval flow.

Conclusions

Our experiments show that a totally implantable iATVA system is feasible, which will eliminate the need for external power for Fontan mechanical venous assist and combat gradual postoperative venous remodeling and Fontan failure.

Life After Surviving Fontan Surgery: A Meta-Analysis of the Incidence and Predictors of Late Death

AIM

We now know that 20-40% of patients with a single ventricle will develop heart failure after the second decade post-Fontan surgery. However, we remain unable to risk-stratify the cohort to identify patients at highest risk of late failure and death. We conducted a systematic review of all reported late outcomes for patients with a Fontan circulation to identify predictors of late death.

METHODS

We searched MEDLINE, Embase and PubMed with subject terms ("single ventricle", "Hypoplastic left heart syndrome", "congenital heart defects" or "Fontan procedure") AND ("heart failure", "post-operative complications", "death", "cause of death", "transplantation" or "follow-up studies") for relevant studies between January 1990 and December 2015. Variables identified as significant predictors of late death on multivariate analysis were collated for meta-analysis. Survival data was extrapolated from Kaplan-Meier survival curves to generate a distribution-free summary survival curve.

RESULTS

Thirty-four relevant publications were identified, with a total of 7536 patients included in the analysis. Mean follow-up duration was 114 months (range 24-269 months). There were 688 (11%) late deaths. Predominant causes of death were late Fontan failure (34%), sudden death (19%) and perioperative death (16%). Estimated mean survival at 5, 10 and 20 years post Fontan surgery were 95% (95%CI 93-96), 91% (95%CI 89-93) and 82% (95%CI 77-85). Significant predictors of late death include prolonged pleural effusions post Fontan surgery (HR1.18, 95%CI 1.09-1.29, p<0.001), protein losing enteropathy (HR2.19, 95%CI 1.69-2.84, p<0.001), increased ventricular end diastolic volume (HR1.03 per 10ml/BSA increase, 95%CI 1.02-1.05, p<0.001) and having a permanent pacemaker (HR12.63, 95%CI 6.17-25.86, p<0.001).

CONCLUSIONS

Over 80% of patients who survive Fontan surgery will be alive at 20 years. Developing late sequelae including protein losing enteropathy, ventricular dysfunction or requiring a pacemaker predict a higher risk of late death.

The cardiotomy reservoir - a preliminary evaluation of a new cell source for cardiovascular tissue engineering

OBJECTIVES

Cell sources for cardiovascular tissue engineering (TE) are scant. However, the need for an ideal TE cardiovascular implant persists. We investigated the cardiotomy reservoir (CR) as a potential cell source that is more accessible and less ethically problematic.

METHODS

CR (n = 10) were removed from the bypass system after surgery. Isolation was performed using different isolation methods: blood samples were taken from the cardiopulmonary bypass and centrifuged at low density. The venous filter screen was cut out and placed into petri dishes for cultivation. The spongelike filter was removed, washed and treated in the same way as the blood samples. After cultivation, cell lines of fibroblasts (FB) and endothelial cells (EC) were obtained for analysis. The cells were seeded on polyurethane patches and analyzed via scanning electron microscopy (SEM), Life/Dead assay and immunohistochemistry.

RESULTS

No correlation between age, time of surgery and quality of cells was observed. The successful extraction of FB and was proven by positive staining results for TE-7, CD31 and vWF. Cell morphology, cytoskeleton staining and quantification of proliferation using WST-1 assay resembled the cells of the control group in all ways. The topography of a confluent and vital cell layer after cell seeding was displayed by SEM analysis, Life/Dead Assay and immunohistochemistry. The establishment of an extracellular matrix (ECM) was proven by positive staining for collagen IV, laminin, fibronectin and elastin.

CONCLUSIONS

Viable FB and EC cell lines were extracted from the CR after surgery. Easy access and high availability make this cell source destined for widespread application in cardiovascular tissue engineering.

Noninvasive Liver Assessment in Adult Patients With Fontan Circulation Using Acoustic Radiation Force Impulse Elastography and Hepatic Magnetic Resonance Imaging

BACKGROUND

Patients who have undergone the Fontan procedure are at risk of developing hepatic dysfunction. However, broad recommendations regarding liver monitoring are limited. The purpose of this study was to characterize the frequency of liver disease in adult Fontan patients using multimodality imaging (hepatic magnetic resonance imaging [MRI], acoustic radiation force impulse [ARFI] elastography, or hepatic ultrasound).

METHODS

In a prospective cross-sectional analysis of adult patients palliated with a Fontan procedure, hepatic MRI, ARFI, and hepatic ultrasound were used to assess for liver disease. The protocol compared (1) varying prevalence of liver disease based on each imaging technique, (2) agreement between different techniques, and (3) association between noninvasive imaging diagnosis of liver disease and clinical variables, including specific liver disease biomarkers.

RESULTS

Thirty-seven patients were enrolled. The ARFI results showed high wave propagation velocity in 35 patients (94.6%). All patients had some abnormality in the hepatic MRI. Specifically, 8 patients (21.6%) showed signs of chronic liver disease, 10 patients (27%) had significant liver fibrosis, and 27 patients (73%) had congestion. No correlation was found between liver stiffness measured as propagation velocity and hepatic MRI findings. Only 7 patients had an abnormal hepatic ultrasound study.

CONCLUSIONS

There is an inherent liver injury in adult Fontan patients. Signs of liver disease were observed in most patients by both hepatic MRI and ARFI elastography but not by ultrasound imaging. Increased liver stiffness did not identify specific disease patterns from MRI, supporting the need for multimodality imaging to characterize liver disease in Fontan patients.

Predictors of health-related quality of life in children with chronic heart disease

OBJECTIVE

Chronic paediatric heart disease is often associated with residual symptoms, persisting functional restrictions, and late sequelae for psychosocial development. It is, therefore, increasingly important to evaluate the health-related quality of life of children and adolescents with chronic heart disease. The aim of this study was to determine medical and socio-demographic variables affecting health-related quality of life in school-aged children and adolescents with chronic heart disease. Patients and methods The Pediatric Cardiac Quality of Life Inventory was administered to 375 children and adolescents and 386 parental caregivers. Medical information was obtained from the charts. The socio-demographic information was provided by the patients and caregivers.

RESULTS

Greater disease severity, low school attendance, current cardiac medication, current parental employment, uncertain or limited prognosis, history of connection to a heart-lung machine, number of nights spent in a hospital, and need for treatment in a paediatric aftercare clinic independently contributed to lower health-related quality of life (self-report: R2=0.41; proxy-report: R2=0.46). High correlations between self-reports and parent-proxy reports indicated concordance regarding the evaluation of a child's health-related quality of life.

CONCLUSIONS

Beyond medical treatment, integration into school is important to increase health-related quality of life in children and adolescents surviving with chronic heart disease. Regular screening of health-related quality of life is recommended to identify patients with special needs.

Ventricular Arrhythmias in Adult Congenital Heart Disease: Mechanisms, Diagnosis, and Clinical Aspects

The risk of ventricular arrhythmias in the adult congenital heart disease population increases with age. The mechanism, type, and frequency vary depending on the complexity of the defect, whether it has been repaired, and the type and timing of repair. Risk stratification for sudden death in patients with congenital heart disease is often challenging. Current recommendations provide a useful guide for management of these patients and risk stratification continues to evolve. Internal cardiac defibrillator implantation is often challenging due to limited transvenous access, often resulting in the need for epicardial or subcutaneous devices.

Tricuspid Atresia IIc With a Vascular Ring: Novel Approach for Fontan Completion

We report a successful Fontan completion in a 22-month-old boy with tricuspid atresia (TA) IIc with a vascular ring. The patient was referred at 1 month of age and was diagnosed with TA IIc using echocardiography. Subsequent 3-dimensional computed tomography revealed a vascular ring. We describe a reconstructive approach for such a heart defect, involving a Damus-Kaye-Stansel (DKS) anastomosis reduction plasty combined with a bidirectional cavopulmonary shunt (BCPS) created by end-to-end suturing of the right superior vena cava (SVC) to the left central pulmonary artery (PA), called the SVC translocation technique.

Respiratory Effects on Fontan Circulation During Rest and Exercise Using Real-Time Cardiac Magnetic Resonance Imaging

BACKGROUND

It is known that respiration modulates cavopulmonary flows, but little data compare mean flows under breath-holding and free-breathing conditions to isolate the respiratory effects and effects of exercise on the respiratory modulation.

METHODS

Real-time phase-contrast magnetic resonance combined with a novel method to track respiration on the same image acquisition was used to investigate respiratory effects on Fontan caval and aortic flows under breath-holding, free-breathing, and exercise conditions. Respiratory phasicity indices that were based on beat-averaged flow were used to quantify the respiratory effect.

RESULTS

Flow during inspiration was substantially higher than expiration under the free-breathing and exercise conditions for both inferior vena cava (inspiration/expiration: 1.6 ± 0.5 and 1.8 ± 0.5, respectively) and superior vena cava (inspiration/expiration: 1.9 ± 0.6 and 2.6 ± 2.0, respectively). Changes from rest to exercise in the respiratory phasicity index for these vessels further showed the impact of respiration. Total systemic venous flow showed no significant statistical difference between the breath-holding and free-breathing conditions. In addition, no substantial difference was found between the descending aorta and inferior vena cava mean flows under either resting or exercise conditions.

CONCLUSIONS

This study demonstrated that inferior vena cava and superior vena cava flow time variance is dominated by respiratory effects, which can be detected by the respiratory phasicity index. However, the minimal respiration influence on net flow validates the routine use of breath-holding techniques to measure mean flows in Fontan patients. Moreover, the mean flows in the inferior vena cava and descending aorta are interchangeable.

Improved Exercise Performance in Patients With Tricuspid Atresia After the Fontan-Björk Modification With Pulsatile Systolic Pulmonary Flow

BACKGROUND

After the Fontan-Björk modification for tricuspid atresia, some patients show pulsatile systolic pulmonary flow. We compared the hemodynamic findings and the clinical presentation of patients with and without pulsatile systolic flow after atrioventricular connection.

METHODS

According to the pulmonary flow pattern by pulsed-wave Doppler assessment of transthoracic echocardiography, 41 patients after atrioventricular connection were divided into two groups: patients who showed dominant pulsatile systolic pulmonary flow (group P, n = 11), and patients who did not (group N, n = 30).

RESULTS

Mean follow-up time was 27.8 ± 4.7 years in group P and 25.3 ± 3.8 years in group N (p = 0.1). Patients in group P had significantly less frequently catheter ablation procedures for tachyarrhythmia (9% versus 50%, p = 0.03). No patient in group P had had cardiac decompensation, whereas 7 patients (23%) in group N had had an episode of cardiac decompensation (p = 0.08). Cardiopulmonary exercise testing revealed that patients in group P showed higher oxygen uptake compared with patients in group N (25.0 ± 7.3 versus 19.6 ± 6.0 mL · kg(-1) · min(-1), p = 0.03). Patients in group P showed higher systolic pulmonary artery pressure (21.3 ± 8.4 versus 16.8 ± 4.5 mm Hg, p = 0.05), higher right ventricular end-diastolic volume index (88.6 ± 30.2 versus 50.3 ± 28.5 mL · L(-1) · m(-2), p = 0.03), and higher right ventricle to left ventricle ratio of end-diastolic volume index (1.4 ± 0.6 to 0.7 ± 0.3, p = 0.01).

CONCLUSIONS

Patients with pulsatile systolic flow in the pulmonary artery had better hemodynamic and better exercise performance compared with patients without pulsatile systolic flow after atrioventricular connection. A sufficient volume and function of the right ventricle is a prerequisite to create pulsatile systolic flow.

Unsatisfactory Early and Late Outcomes After Fontan Surgery Delayed to Adolescence and Adulthood

The ideal age to perform the Fontan procedure is still unknown. The aim of this study is to determine outcomes after Fontan surgery delayed to adolescence and adulthood in Australia and New Zealand. Patients who had undergone a Fontan procedure at 15 years of age or older were identified in the 1133 patients registered in the Australia and New Zealand Fontan Registry until December 2012. A total of 45 patients underwent the following Fontan procedure at a median age of 18.3 years (16-21 years): 24 atriopulmonary connections, 10 lateral tunnel, and 11 extracardiac conduits. Hospital mortality was 13% (6 of 45). After a mean follow-up of 15.5 ± 9 years, there were 8 late deaths. Survival rates after 10, 20, and 25 years were 79% (95% CI: 64-89), 70% (95% CI: 51-83), and 70% (95% CI: 51-83), respectively. Freedom from Fontan failure (death, heart transplantation, Fontan takedown, protein-losing enteropathy, and poor functional status) after 10 and 20 years was 63% (95% CI: 47-76) and 35% (95% CI: 19-52), respectively. Patients with a single left ventricle had a lower risk of failure (hazard ratio = 0.25, 95% CI: 0.10-0.59; P = 0.002). Arrhythmias developed in 29 patients after a median of 0.1 years (0-9.3 years) and 10 required a permanent pacemaker. Freedom from all adverse events at 10 years was 30% (95% CI: 16-45). Outcomes of the Fontan procedure in adolescents and adults are poor, with disproportionately high hospital mortality and late adverse events. The Fontan procedure should not be delayed to adolescence and adulthood and should be performed electively in childhood.

Risk factors for major adverse events late after Fontan palliation

OBJECTIVE

Risk factors for major adverse events late after Fontan palliation are unknown. Prior studies have suggested ventricular function and morphology as important risk factors. The aim of this study is to (1) characterize the late major adverse event profile in adult Fontan patients and (2) identify additional risk factors that may contribute to adverse outcomes.

DESIGN AND SETTING

A retrospective review of all adult patients >15 years post-Fontan seen at a tertiary academic center was conducted. Clinical, laboratory, cardiac data, and abdominal imaging were collected via chart review. Major adverse events (death, cardiac transplantation, or listing) were identified, and timing of events was plotted using Kaplan-Meier methods. Univariate and multivariate logistic regression was used to determine independent predictors of late-term events.

RESULTS

A total of 123 adult Fontan patients were identified (mean time post-Fontan 22.4 years [±4.4]). Major adverse events occurred in 19/123 patients (15%). In this 15-year survivor cohort, transplant-free survival rates were 94.6%, 82.9%, and 59.8% at 20, 25, and 30 years postoperation, respectively. Modes of death were Fontan failure with preserved function (4), congestive heart failure with decreased function (2), sudden death (2), thromboembolic event (1), post-Fontan conversion (2), and posttransplant (2). No differences in adverse outcomes were found based on morphology of the systemic ventricle, Fontan type, or systolic ventricular function. On the other hand, features of portal hypertension (OR 19.0, CI 4.7-77.3, P < .0001), presence of a pacemaker (OR 13.4, CI 2.6-69.8, P = .002), and systemic oxygen desaturation (OR 0.86, CI 0.75-0.98, P = .02) were risk factors for major adverse events in the multivariate analysis.

CONCLUSIONS

In adult Fontan patients surviving >15 years post-Fontan, portal hypertension, oxygen desaturation, and need for pacemaker were predictive of adverse events. Traditional measures may not predict late-term outcomes in adult survivors; further study of the liver's role in late outcomes is warranted.

Percutaneous fetal cardiac interventions for structural heart disease

INTRODUCTION

Prenatal diagnosis provides valuable information regarding a variety of congenital heart defects. Some defects occur early in gestation with little change throughout pregnancy, whereas others evolve during mid and late gestation. Fetal cardiac intervention (FCI) affords the opportunity to interrupt progression of disease in this latter category, resulting in improved perinatal and lifelong outcomes.

AIM

This chapter addresses three lesions for which percutaneous FCI can be utilized: (1) aortic stenosis with evolving hypoplastic left heart syndrome, for which aortic valvuloplasty may prevent left ventricular hypoplasia and has yielded a biventricular circulation in approximately one third of cases; (2) hypoplastic left heart syndrome with intact atrial septum, for which relief of atrial restriction has potential to improve perinatal survival; and (3) pulmonary atresia with intact ventricular septum and evolving right ventricular hypoplasia, for which pulmonary valvuloplasty has resulted in a biventricular circulation in the majority of patients. The pathophysiology, rationale for intervention, patient selection criteria, procedural technique, and outcomes for each lesion will be reviewed. This chapter will also review complications of FCI and their treatment, and maternal and fetal anesthesia specific to FCI. The importance of a specialized center with experience managing infants delivered after FCI will also be addressed.

Quantitative evaluation of hemodynamics in the Fontan circulation: a cross-sectional study measuring energy loss in vivo

Flow energy loss (EL) at the Fontan anastomosis has been thought to reflect flow efficiencies and to influence on hemodynamics in the Fontan circulation and has been often discussed in numerical studies. However, in vivo EL measurements have to date not been reported. We directly measured EL in the Fontan circulation and examined the relationship between the structural configuration and EL, as well as the influence of EL, on the hemodynamics in the Fontan circulation. We performed a catheterization study measuring simultaneous pressure and flow velocity to calculate EL in nine patients (mean age 2.3 ± 0.3 years) 1 year after the Fontan procedure. The measured EL was 9.66 ± 8.50 mW. One patient with left pulmonary artery stenosis recorded the highest EL (17.78 mW), and one patient with bilateral superior vena cava and left phrenic nerve palsy recorded the second highest EL (14.62 mW). EL significantly correlated with time constant tau and weakly with max-dp/dt during the isovolumic diastolic phase (r = 0.795 and -0.574, respectively). EL also correlated with max-dp/dt during the isovolumic systolic phase (r = 0.842) but not with ejection fraction or systemic blood flow (r = 0.384 and -0.034, respectively). In conclusion, inefficient structural configuration and phrenic nerve palsy seem to be related with increased in EL at the Fontan anastomosis. Although these preliminary findings also suggest that EL is associated with an impaired relaxation of the ventricle, a long-term study with a large population is warranted to reach such a definitive conclusion.

Clinical research priorities in adult congenital heart disease

BACKGROUND

Adult congenital heart disease (ACHD) clinicians are hampered by the paucity of data to inform clinical decision-making. The objective of this study was to identify priorities for clinical research in ACHD.

METHODS

A list of 45 research questions was developed by the Alliance for Adult Research in Congenital Cardiology (AARCC), compiled into a survey, and administered to ACHD providers. Patient input was sought via the Adult Congenital Heart Association at community meetings and online forums. The 25 top questions were sent to ACHD providers worldwide via an online survey. Each question was ranked based on perceived priority and weighted based on time spent in ACHD care. The top 10 topics identified are presented and discussed.

RESULTS

The final online survey yielded 139 responses. Top priority questions related to tetralogy of Fallot (timing of pulmonary valve replacement and criteria for primary prevention ICDs), patients with systemic right ventricles (determining the optimal echocardiographic techniques for measuring right ventricular function, and indications for tricuspid valve replacement and primary prevention ICDs), and single ventricle/Fontan patients (role of pulmonary vasodilators, optimal anticoagulation, medical therapy for preservation of ventricular function, treatment for protein losing enteropathy). In addition, establishing criteria to refer ACHD patients for cardiac transplantation was deemed a priority.

CONCLUSIONS

The ACHD field is in need of prospective research to address fundamental clinical questions. It is hoped that this methodical consultation process will inform researchers and funding organizations about clinical research topics deemed to be of high priority.

The adult with a fontan: a panacea without a cure? Review of long-term complications

The univentricular heart includes a spectrum of complex cardiac defects that are managed by staged palliative surgical procedures, ultimately resulting in a Fontan procedure. Since 1971, when it was first developed, the procedure has undergone several variations. These patients require lifelong management, including a thorough knowledge of their anatomic substrate, hemodynamic status, management of rhythm and ventricular function, together with multi-organ evaluation. As these patients enter middle age, there is increasing awareness of long-term complications and mortality. This review highlights the concept behind the staged surgical palliations, the unique single ventricle physiology and the long-term complications in this complex cohort of patients.

Trends in mortality (1975-2011) after one- and two-stage Fontan surgery, including bidirectional Glenn through Fontan completion

OBJECTIVES

Techniques and strategies in the Fontan procedure have evolved over the years, including the evolution from a one- to two-stage procedure. With such adjustments made, attention should shift towards survival analysis, including bidirectional cavopulmonary shunt (BCPS) and interstage mortality. The purpose of this study was to investigate the trends in the overall mortality of all patients who underwent a BCPS or one-stage Fontan procedure at our institution in the period of 1975-2011.

METHODS

Using a single-institution, retrospective design, we reviewed the patient records of 203 patients from the University Medical Center Groningen, Netherlands, who underwent a Fontan procedure or a BCPS (with the intention to complete cavopulmonary connection at a second later stage) between 1975 and 2011. Trends in mortality were investigated by comparing survival rates during four consecutive decades (1975-84; 1985-94; 1995-2004; 2005-11), and predictors for mortality were identified.

RESULTS

During a mean follow-up of 12 years, survival was 69%. Overall mortality declined significantly during the past decades (P = 0.017). This was driven by a decrease in early mortality (P = 0.016), whereas no changes in late mortality could be demonstrated. Multivariate analyses identified a diagnosis of heterotaxy (P = 0.049) and an atriopulmonary connection type of Fontan circulation (P = 0.015) as independent risk factors for overall mortality.

CONCLUSIONS

We demonstrate that, with the inclusion of first-stage and interstage mortality also, overall survival after Fontan procedures improved over time. This improvement, however, is mainly caused by a decline in early mortality. Improvement in long-term survival of patients operated on over the past four decades could not (yet) be demonstrated in this series.

Magnetic resonance imaging identifies unsuspected liver abnormalities in patients after the Fontan procedure

OBJECTIVE

To determine whether abdominal magnetic resonance imaging (MRI) detects hepatic abnormalities before clinical or biochemical perturbations in patients after the Fontan procedure.

STUDY DESIGN

Thirty-nine children and adolescents who underwent the Fontan procedure and were referred to a pediatric hepatologist by cardiology services between 2011 and 2012 were reviewed retrospectively. Physical examination findings, routine laboratory tests of liver function, evaluation for chronic liver disease, and abdominal MRI findings were recorded. MRI findings were evaluated relative to time elapsed since surgery by 2 radiologists (blinded).

RESULTS

Assessment for coexisting chronic liver disease was negative in all patients. All patients had a normal serum albumin level and International Normalized Ratio. Twenty-six of the 39 patients (67%) underwent abdominal MRI, 4 had MRI-incompatible hardware, and 9 did not undergo MRI because of insurance denial. All MRI scans demonstrated morphologic liver changes with varying degrees of reticular contrast enhancement compatible with fibrosis and congestion. Reticular contrast enhancement was often nonuniform, and 9 patients (35%) had multifocal arterially enhancing lesions.

CONCLUSION

MRI can identify hepatic abnormalities in patients after Fontan surgery that go undetected by standard clinical and laboratory assessments. These abnormalities are not uniformly distributed throughout the liver, and thus assessment by liver biopsy analysis is subject to sampling error.

Combined Heart Transplantation and Thoracic Endovascular Aortic Repair for Heart Failure Secondary to Tricuspid Atresia Palliated with Potts Shunt

A 57-year-old-man with known tricuspid atresia previously palliated with a Potts shunt had developed progressive heart failure refractory to medical management. He underwent a combined thoracic endovascular stent graft procedure to eliminate the Potts shunt and orthotopic heart transplantation. At 3-month follow-up, right-sided heart function and pulmonary artery pressures as well as pulmonary vascular resistance had normalized, and at 7 months, the patient had returned to normal activity. The surgical management and its principles as well as postoperative follow-up are described.

Treatment planning for a TCPC test case: a numerical investigation under rigid and moving wall assumptions

The hemodynamics in patients with total cavopulmonary connections (TCPC) is generally very complex and characterized by patient-to-patient variability. To better understand its effect on patients' outcome, CFD models are widely used, also to test and optimize surgical options before their implementation. These models often assume rigid geometries, despite the motion experienced by thoracic vessels that could influence the hemodynamics predictions. By improving their accuracy and expanding the range of simulated interventions, the benefit of treatment planning for patients is expected to increase. We simulate three types of intervention on a patient-specific 3D model, and compare their predicted outcome with baseline condition: a decrease in pulmonary vascular resistance obtainable with medications; a surgical revision of the connection design; the introduction of a fenestration in the TCPC wall. The simulations are performed both with rigid wall assumption and including patient-specific TCPC wall motion, reconstructed from a 4DMRI dataset. The results show the effect of each option on clinically important metrics and highlight the impact of patient-specific wall motion. The largest differences between rigid and moving wall models are observed in measures of energetic efficiency of TCPC as well as in hepatic flow distribution and transit time of seeded particles through the connection.

Acute histological changes of the lung after experimental Fontan circulation in a swine model

Background

Histological changes of the lungs were studied after the establishment of a modified total cavopulmonary connection (TCPC) without the use of cardiopulmonary bypass (CPB) or other means of temporary bypass on a swine model.

Material/Methods

8 open chest-anesthetized pigs Landrace × Large White pigs (mean weight 43kg, mean age 4.5 months) underwent TCPC by the use of an appropriate size Y-shaped conduit connecting the superior and inferior caval veins (end-to-end anastomosis) to the pulmonary trunk (end-to-side anastomosis). After sternotomy, a wedge resection of the lung parenchyma was performed at baseline. Hemodynamic stability was sustained after TCPC establishment and 2 hours later another wedge resection of the lung was performed (from the same anatomic area). Histological studies were conducted by hematoxylin and eosin staining.

Results

All samples (n=8) at baseline were consistent with normal lung parenchyma. After the establishment of TCPC, all samples (n=8) revealed moderate mononuclear infiltration adjacent to pulmonary alveoli and bronchioles, findings compatible with bronchiolitis.

Conclusions

In a normal swine model, 2 hours after the establishment of Fontan circulation without the use of CPB, pathologic examination of the lungs revealed bronchiolitis. Further research is needed to clarify these findings and the potential implications to the Fontan circulation, either immediate or long-term.

Effects of lack of pulsatility on pulmonary endothelial function in the Fontan circulation

OBJECTIVES

Continuous flow in the Fontan circulation results in impairment of pulmonary artery endothelial function, increased pulmonary arterial resistance, and, potentially, late failure of Fontan circulation. We investigated the mechanisms of vascular remodeling and altered vascular reactivity associated with chronic privation of pulsatility on pulmonary vasculature.

METHODS

A total of 30 pigs were evenly distributed in 3 groups: 10 underwent a sham procedure (group I) and 20 underwent a cavopulmonary shunt between the superior vena cava and right pulmonary artery--10 with complete ligation of the proximal right pulmonary artery (group II, nonpulsatile) and 10 with partial ligation (group III, micropulsatile). At 3 months postoperatively, the in vivo hemodynamics, in vitro vasomotricity (concentration response curves on pulmonary artery isolated rings), and endothelial nitric oxide synthase protein level were assessed. A comparison between group and between the right and left lung in each group was performed.

RESULTS

Group II developed right pulmonary hypertension and increased right pulmonary resistance. Endothelial function was altered in group II, as reflected by a decrease in the vasodilation response to acetylcholine and ionophoric calcium but preservation of the nonendothelial-dependent response to sodium nitroprusside. Group III micropulsatility attenuated pulmonary hypertension but did not prevent impairment of the endothelial-dependant relaxation response. Right lung Western blotting revealed decreased endothelial nitric oxide synthase in group II (0.941 ± 0.149 vs sham 1.536 ± 0.222, P = .045) that was preserved in group III (1.275 ± 0.236, P = .39).

CONCLUSIONS

In a chronic model of unilateral cavopulmonary shunt, pulsatility loss resulted in an altered endothelial-dependant vasorelaxation response of the pulmonary arteries. Micropulsatility limited the effects of pulsatility loss. These results are of importance for potential therapies against pulmonary hypertension in the nonpulsatile Fontan circulation, by retaining accessory pulmonary flow or pharmaceutical modulation of nonendothelial-dependant pulmonary vasorelaxation.

Effect of flow pulsatility on modeling the hemodynamics in the total cavopulmonary connection

Total cavopulmonary connection is the result of a series of palliative surgical repairs performed on patients with single ventricle heart defects. The resulting anatomy has complex and unsteady hemodynamics characterized by flow mixing and flow separation. Although varying degrees of flow pulsatility have been observed in vivo, non-pulsatile (time-averaged) boundary conditions have traditionally been assumed in hemodynamic modeling, and only recently have pulsatile conditions been incorporated without completely characterizing their effect or importance. In this study, 3D numerical simulations with both pulsatile and non-pulsatile boundary conditions were performed for 24 patients with different anatomies and flow boundary conditions from Georgia Tech database. Flow structures, energy dissipation rates and pressure drops were compared under rest and simulated exercise conditions. It was found that flow pulsatility is the primary factor in determining the appropriate choice of boundary conditions, whereas the anatomic configuration and cardiac output had secondary effects. Results show that the hemodynamics can be strongly influenced by the presence of pulsatile flow. However, there was a minimum pulsatility threshold, identified by defining a weighted pulsatility index (wPI), above which the influence was significant. It was shown that when wPI<30%, the relative error in hemodynamic predictions using time-averaged boundary conditions was less than 10% compared to pulsatile simulations. In addition, when wPI<50, the relative error was less than 20%. A correlation was introduced to relate wPI to the relative error in predicting the flow metrics with non-pulsatile flow conditions.

Comparing pre- and post-operative Fontan hemodynamic simulations: implications for the reliability of surgical planning

Virtual modeling of cardiothoracic surgery is a new paradigm that allows for systematic exploration of various operative strategies and uses engineering principles to predict the optimal patient-specific plan. This study investigates the predictive accuracy of such methods for the surgical palliation of single ventricle heart defects. Computational fluid dynamics (CFD)-based surgical planning was used to model the Fontan procedure for four patients prior to surgery. The objective for each was to identify the operative strategy that best distributed hepatic blood flow to the pulmonary arteries. Post-operative magnetic resonance data were acquired to compare (via CFD) the post-operative hemodynamics with predictions. Despite variations in physiologic boundary conditions (e.g., cardiac output, venous flows) and the exact geometry of the surgical baffle, sufficient agreement was observed with respect to hepatic flow distribution (90% confidence interval-14 ± 4.3% difference). There was also good agreement of flow-normalized energetic efficiency predictions (19 ± 4.8% error). The hemodynamic outcomes of prospective patient-specific surgical planning of the Fontan procedure are described for the first time with good quantitative comparisons between preoperatively predicted and postoperative simulations. These results demonstrate that surgical planning can be a useful tool for single ventricle cardiothoracic surgery with the ability to deliver significant clinical impact.

Challenges in the management of patients with functionally univentricular heart in Turkey

Management of patients with functionally univentricular heart encompasses a wide array of developments over the years in every country. This article describes our working group experiences and 30-year story of single ventricle surgery in Turkey. Diagnosis, surgical treatment, and medical treatment of this complex group of patients necessitate courageous and continuous team effort with multi-institutional collaboration.

Effect of race on the timing of the Glenn and Fontan procedures for single-ventricle congenital heart disease

OBJECTIVE

Disparities in health care have been documented between different racial groups in the United States. We hypothesize that there will be racial variance in the timing of the Glenn and Fontan procedures for children with single-ventricle physiology.

DESIGN AND SETTING

We performed a retrospective review of a national pediatric intensive care unit database (Virtual PICU Performance System, LLC).

PATIENTS

Children with hypoplastic left heart syndrome, tricuspid atresia, and common ventricle, admitted from January 2006 to July 2008, were included. Data included race, weight, age, medical length of stay, Paediatric Index of Mortality 2 score, and survival.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 423 patients from 29 hospitals. The study population was 7.6% black, 13.0% Hispanic, 59.8% white, 9.2% "other," and 11.6% had missing racial/ethnic information. Diagnoses included 255 patients with hypoplastic left heart syndrome, 91 with tricuspid atresia, and 77 with common ventricle. The median age for the Glenn procedure (n = 205) was 5.5 months (interquartile range, 4.6-7.0 months) and 39.7 months (interquartile range, 32.4-50.6 months) for the Fontan procedure (n = 218). There was no difference between the median age at the time of the Glenn or Fontan procedures between the different racial/ethnic groups (p = .65 and p = .16, respectively). The medical length of intensive care unit stay for patients receiving the Glenn and Fontan procedures was 3.7 days (interquartile range, 1.9-6.1 days) and 3.7 days (interquartile range, 1.9-6.8 days), respectively. There were no differences in medical length of intensive care unit stay for the Glenn procedure between the different racial/ethnic groups (p = .21). Hispanic patients had a longer medical length of intensive care unit stay (6.3 days; interquartile range, 3.1-9.9 days) than white patients (2.9 days; interquartile range, 1.8-5.3 days) for the Fontan procedure (p = .008).

CONCLUSION

The timing of single-ventricle palliative procedures was not affected by race/ethnicity.

Extracardiac complications of the Fontan circuit

The Fontan operation is the primary surgical procedure used in the palliation of patients with univentricular cardiac physiology. With improved survival of children with congenital heart disease, long-term complications of the Fontan circuit are being encountered more frequently. Radiologists are more likely to see both the cardiac and extracardiac complications of the Fontan circuit. Awareness of the common extracardiac complications in children with failing Fontan circuits will aid the radiologist in making the appropriate diagnosis and guide the cardiologist caring for these patients.