Functionally univentricular heart and the fontan operation: lessons learned about patterns of practice and outcomes from the congenital heart surgery databases of the European association for cardio-thoracic surgery and the society of thoracic surgeons

Surgical Considerations in Adult Congenital Heart Disease Heart Failure

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

Outcomes of the Kawashima: A Society of Thoracic Surgeons Congenital Heart Surgery Database Analysis

BACKGROUND

We aimed to evaluate the effect of age at operation on postoperative outcomes in children undergoing a Kawashima operation.

METHODS

The Society of Thoracic Surgeons Congenital Heart Surgery Database was queried for Kawashima procedures from January 1, 2014, to June 30, 2020. Patients were stratified by age at operation in months: 0 to <4, 4 to <8, 8 to <12, and >12. Subsequently, outcomes for those in whom the Kawashima was not the index operation and for those undergoing hepatic vein incorporation (Fontan completion or hepatic vein-to-azygos vein connection) were evaluated.

RESULTS

We identified 253 patients who underwent a Kawashima operation (median age, 8.6 months; median weight, 7.4 kg): 12 (4.7%), 0 to <4 months; 96 (37.9%), 4 to <8 months; 81 (32.0%), 8 to <12 months; and 64 (25.3%), >12 months. Operative mortality was 0.8% (n = 2), with major morbidity or mortality in 17.4% (n = 44), neither different across age groups. Patients <4 months had a longer postoperative length of stay (12.5 vs 9.3 days; P = .03). The Kawashima was not the index operation of the hospital admission in 15 (5.9%); these patients were younger (6.0 vs 8.4 months; P = .05) and had more preoperative risk factors (13/15 [92.9%] vs 126/238 [52.9%]; P < .01). We identified 173 patients undergoing subsequent hepatic vein incorporation (median age, 3.9 years; median weight, 15.0 kg) with operative mortality in 6 (3.5%) and major morbidity or mortality in 30 (17.3%).

CONCLUSIONS

The Kawashima is typically performed between 4 and 12 months with low mortality. Morbidity and mortality were not affected by age. Hepatic vein incorporations may be higher risk than in traditional Fontan procedures, and ways to mitigate this should be sought.

Preoperative versus postoperative survival in patients with univentricular heart: a nationwide, retrospective study of patients born in 1990-2015

OBJECTIVES

Few data exist on mortality among patients with univentricular heart (UVH) before surgery. Our aim was to explore the results of intention to perform surgery by estimating preoperative vs postoperative survival in different UVH subgroups.

DESIGN

Retrospective.

SETTING

Tertiary centre for congenital cardiology and congenital heart surgery.

PARTICIPANTS

All 595 Norwegian children with UVH born alive from 1990 to 2015, followed until 31 December 2020.

RESULTS

One quarter (151/595; 25.4%) were not operated. Among these, only two survived, and 125/149 (83.9%) died within 1 month. Reasons for not operating were that surgery was not feasible in 31.1%, preoperative complications in 25.2%, general health issues in 23.2% and parental decision in 20.5%. In total, 327/595 (55.0%) died; 283/327 (86.5%) already died during the first 2 years of life. Preoperative survival varied widely among the UVH subgroups, ranging from 40/65 (61.5%) among patients with unbalanced atrioventricular septal defect to 39/42 (92.9%) among patients with double inlet left ventricle. Postoperative survival followed a similar pattern. Postoperative survival among patients with hypoplastic left heart syndrome (HLHS) improved significantly (5-year survival, 42.5% vs 75.3% among patients born in 1990-2002 vs 2003-2015; p<0.0001), but not among non-HLHS patients (65.7% vs 72.6%; p=0.22)-among whom several subgroups had a poor prognosis similar to HLHS. A total of 291/595 patients (48.9%) had Fontan surgery CONCLUSIONS: Surgery was refrained in one quarter of the patients, among whom almost all died shortly after birth. Long-term prognosis was largely determined during the first 2 years. There was a strong concordance between preoperative and postoperative survival. HLHS survival was improved, but non-HLHS survival did not change significantly. This study demonstrates the complications and outcomes encountering newborns with UVH at all major stages of preoperative and operative treatment.

Pre- and Post-operative determinants of transplantation-free survival after Fontan. The Australia and New Zealand experience

Background

This review identifies the predictors of late mortality and heart transplantation that remain relevant in the contemporary population of patients with a Fontan circulation, focusing on the potential impact of post-Fontan morbidities on the late outlook of these patients.

Methods and Results

A total of 1561 patients who had survived the Fontan operation in Australia or New Zealand from 1975 to 2018 were included in this review. Over a median duration of 11.4 years, there was a total of 117 deaths (7%) and 32 heart transplantations (2%). Freedom from death and heart transplantation at 10, 20 and 35 years post Fontan surgery were 94% (95% CI 93–95%), 87% (95 %CI 85–90%) and 66% (95 %CI 57–78%) respectively. Being male, having an atriopulmonary Fontan, pre-Fontan atrioventricular valve intervention, or prolonged pleural effusions post Fontan were predictive of late death or heart transplantation. However, time-dependent variables such as the development of atrial arrhythmia, protein/losing enteropathy or late ventricular dysfunction were stronger predictors of the same outcome. Patients who developed a time-dependent risk factor had a freedom from death and heart transplantation rate of 54% (95 %CI 43–66) at 15 years and 44% (95 %CI 33–57) at 25 years post Fontan. However, 95% (95 %CI 91–99) of patients without any of the identified risk factors were free from death or heart transplantation rate at 25 years post Fontan.

Conclusion

In conclusion, the occurrence of post-operative complications such as PLE, arrhythmia and ventricular dysfunction will likely precede the late demise of these patients.

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.

11 Years of the Fontan operation at a single institution: Results from 87 consecutive patients

Fontan procedure is the preferred palliation for patients with single ventricles.

OBJECTIVES

To evaluate early morbidity and mortality after Fontan operation in 87 consecutive patients, between 2007 and 2017.

METHODS

Early survival, duration of intensive care unit (ICU), and hospital stays were the main outcomes evaluated. Potential influencing factors evaluated included preoperative and intraoperative variables.

RESULTS

Fontan procedure was performed at a median age of 4.2 years (range, 17 months-26 years), and a median weight of 15.5 kg (range, 8-72 kg). Extracardiac Fontan was the procedure of choice. The median cardiopulmonary bypass time was 122  minutes (range, 58-550 minutes). The majority had a fenestration (75 out of 87). Postoperatively, the median duration of ICU stay and total hospital stay were (4, 1-76 days) and (16, 1-85 days), respectively. Fontan failure occurred in one patient (1%). Overall early survival was 94%, resulting in a mortality rate of 6%. Univariate analysis showed that heterotaxy (odds ratio [OR], 2.222; confidence interval [CI], 1.345-6.250; P = .003) and decreased ventricular function (OR, 2.207; CI, 1.348-6.061; P = .002) significantly decreased survival. The same analysis failed to identify any statistically significant risk factors for prolonged hospital and ICU stays.

CONCLUSION

Our reported mortality and morbidity rates compared favorably with the reported rates. Therefore, Fontan operation can be performed in a tertiary care center in the United Arab Emirates with favorable early postoperative outcomes.

Transplantation of the failing Fontan

Half a century has passed since the original Fontan palliation. In the interim, surgical and medical advancements have allowed more single ventricle patients to reach Fontan and long-term survival for Fontan patients to improve significantly. However, the risk for Fontan failure and need for heart transplantation remains. In this article we discuss mechanisms of Fontan failure, risk factors and special considerations for Fontan patients in both medical and surgical management around heart transplantation and provide an updated review of survival for Fontan patients after heart transplantation.

Multimodality Screening of Hepatic Nodules in Patients With Congenital Heart Disease After Fontan Procedure: Role of Ultrasound, ARFI Elastography, CT, and MRI

OBJECTIVE

Currently, there is no consensus in the literature regarding the screening of hepatic nodules in patients who have undergone the Fontan procedure. The objectives of this study are to evaluate in this population the frequency of hepatic nodules at ultrasound (US), CT, and MRI; to measure liver stiffness using acoustic radiation force impulse (ARFI) elastography; and to investigate predictive factors for hepatic nodules.

SUBJECTS AND METHODS

In this cross-sectional study, 49 patients who underwent the Fontan procedure were prospectively recruited from August 2014 through June 2016. These patients underwent clinical evaluation for hepatic disorders, ARFI elastography, US, CT, and MRI.

RESULTS

Most of the patients had no symptoms, and hepatic nodules were detected in three of 49 (6.1%) patients at US, 14 of 44 (31.8%) patients at CT, and 19 of 48 (39.6%) patients at MRI. Liver stiffness at ARFI elastography was significantly higher in patients with hepatic nodules than in patients without such nodules (2.64 ± 0.81 m/s vs 1.94 ± 0.49 m/s; p = 0.002) and was a significant predictor of hepatic nodule (AUC, 0.767; p = 0.002). No clinical or laboratory data had any significant correlation with the existence of hepatic nodules, including time since Fontan procedure.

CONCLUSION

In our study, more than one-third of patients had hepatic nodules at CT or MRI, but US did not detect most hepatic nodules. Liver stiffness at ARFI elastography was significantly higher in patients with hepatic nodules, and it may help guiding which patient should be further imaged with CT or MRI.

Incidence and Outcomes of Patients with Functionally Univentricular Heart Born in Latvia, 2007 to 2015

Background and Objectives: A functionally univentricular heart is the term used to describe congenital heart defects where it is impossible to restore two pumping chambers. These lesions are associated with high mortality, morbidity, and medical resource utilization. The aim of this study was to review incidence and outcomes of patients with a functionally univentricular heart at the only pediatric cardiac surgery center in Latvia. Methods: We performed a retrospective review of medical records of (i) all children with a functionally univentricular heart treated at the Clinic of Pediatric Cardiology and Cardiac Surgery, and (ii) all prenatally diagnosed cases of univentricular heart at Children’s Clinical University Hospital in Latvia. We reviewed data regarding children born from January 1, 2007, to December 31, 2015. The children’s cardiac anatomy and interventions were categorized in accordance with the International Pediatric and Congenital Cardiac Code (v3.3). Results: During the study period, 49 patients with a functionally univentricular heart were admitted to Children’s Clinical University Hospital with a corrected incidence of 0.69 per 1000 live births per year. There were 26 patients that had a hypoplastic left ventricle, and 22 patients that had a hypoplastic right ventricle, while one patient had an indeterminate ventricle. Thirty (61.2%) patients had died by the end of data collection. Twenty-one of the 30 deaths occurred before or immediately after stage I surgical palliation. Cumulative neonatal and 5-year survival of patients with a hypoplastic right ventricle was 81.8% and 63.6%, respectively; for patients with hypoplastic left ventricle—46.2% and 17.3%, respectively. Discussion: This is the first mid-term outcome study of patients with a univentricular heart in Latvia. The high mortality reflects the challenges of a small-volume, developing congenital cardiac surgery center. Data from this study will be used as a baseline for quality improvement.

An overview of mechanical circulatory support in single-ventricle patients

The population of people with a single-ventricle is continually increasing due to improvements across the spectrum of medical care. Unfortunately, a proportion of these patients will develop heart failure. Often, for these patients, mechanical circulatory support (MCS) represents the only available treatment option. While single-ventricle patients currently represent a small proportion of the total number of patients who receive MCS, as the single-ventricle patient population increases, this number will increase as well. Outcomes for these complex single-ventricle patients who require MCS has begun to be evaluated. When considering the entire population, survival to hospital discharge is 30-50%, though this must be considered with the significant heterogeneity of the single-ventricle patient population. Patients with a single-ventricle have unique anatomy, mechanisms of failure, indications for MCS and the type of support utilized. This has made the interpretation and the generalizability of the limited available data difficult. It is likely that some subsets will have a significantly worse prognosis and others a better one. Unfortunately, with these limited data, indications of a favorable or poor outcome have not yet been elucidated. Though currently, a database has been constructed to address this issue. While the outcomes for these complex patients is unclear, at least in some situations, they are poor. However, significant advances may provide improvements going forward, including new devices, computer simulations and 3D printed models. The most important factor, however, will be the increased experience gained by the heart failure team to improve patient selection, timing, device and configuration selection and operative approach.

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.

High Overweight and Obesity in Fontan Patients: A 20-Year History

The prevalence of obesity in long-term survivors with complex congenital heart disease may be increasing, and little is known about the timing and onset of weight gain and growth patterns in these high-risk patients. Prevalence rates of overweight/obesity and longitudinal changes in body mass index (BMI) with age were determined in 606 patients with Fontan circulation seen at a tertiary care cardiology center from 1992 to 2012. The number of clinic encounters (n) was stratified by age group (n = 401, 2-5 years; n = 333, 6-11 years; n = 217, 12-19 years; and n = 129, >20 years). Among adults, 39% were overweight/obese at last clinic visit; 22% overweight, and 17% obese. Childhood anthropometric data were available for 82 adults, of which 15% (n = 12/82) were overweight/obese in childhood. The likelihood of being overweight/obese as an adult was three times higher if there was a BMI ≥ 85th percentile in childhood (CI 2.1-4.5, P < 0.01). Overweight/obesity in adulthood was associated with lower heart failure rates (4 vs. 19%, P = 0.03). Pediatric rates of overweight/obesity were comparable to national data (NHANES 2011-2012) in every age group: at 2-5 years, (25 vs. 23%), 6-11 years (26 vs. 34%), and 12-19 years (15 vs. 35%). Systolic blood pressure was higher in overweight/obese children as young as 2-5 years of age. Childhood and adult survivors with Fontan circulation have high rates of overweight/obesity. Childhood obesity is a strong predictor of future adiposity and is linked to changes in systolic blood pressure at a very young age.

The science of assessing the outcomes and improving the quality of the congenital and paediatric cardiac care

PURPOSE OF REVIEW

Although significant progress has been made in the care of patients with paediatric and congenital cardiac disease, optimization of outcomes remains a constant goal. This review article will discuss the latest advances in the science of assessing the outcomes and improving the quality of the congenital and paediatric cardiac care, and will also review some of the latest associated research.

RECENT FINDINGS

Important advances continue to be made in each of the following domains: standardized nomenclature; established uniform core dataset; evaluation of case complexity; verification of the completeness and accuracy of the data; collaboration between subspecialties; strategies for longitudinal follow-up; and incorporating quality improvement. In January 2015, the Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSD) will begin voluntary public reporting of programmatic congenital cardiac surgical outcomes using a new risk model that includes both procedural risk (as defined by the procedure itself and STAT Categories) and a number of patient-specific characteristics including age, weight, prior cardiothoracic operation, prematurity, chromosomal abnormalities, syndromes, noncardiac congenital anatomic abnormalities and preoperative factors. Clinical databases have been linked with administrative database to answer questions neither dataset can answer independently, providing new information about long-term mortality, rates of rehospitalization, long-term morbidity, comparative effectiveness of various treatments, and the cost of healthcare. Multiple research initiatives have recently been published using STS-CHSD.

SUMMARY

The science of assessing the outcomes and improving the quality of congenital and paediatric cardiac care continues to evolve. Recent advances will facilitate the continued evolution of a meaningful method of multiinstitutional outcomes analysis for congenital and paediatric cardiac surgery.

Magnetic Resonance Elastography: A Novel Technique for the Detection of Hepatic Fibrosis and Hepatocellular Carcinoma After the Fontan Operation

OBJECTIVE

To evaluate the utility of magnetic resonance elastography (MRE) in screening patients for hepatic fibrosis, cirrhosis, and hepatocellular carcinoma after the Fontan operation.

PATIENTS AND METHODS

Hepatic MRE was performed in conjunction with cardiac magnetic resonance imaging in patients who had undergone a Fontan operation between 2010 and 2014. Liver stiffness was calculated using previously reported techniques. Comparisons to available clinical, laboratory, imaging, and histopathologic data were made.

RESULTS

Overall, 50 patients at a median age of 25 years (range, 21-33 years) who had undergone a Fontan operation were evaluated. The median interval between Fontan operation and MRE was 22 years (range, 16-26 years). The mean liver stiffness values were increased: 5.5 ± 1.4 kPa relative to normal participants. Liver stiffness directly correlated with liver biopsy-derived total fibrosis score, time since operation, mean Fontan pressure, γ-glutamyltransferase level, Model for End-Stage Liver Disease score, creatinine level, and pulmonary vascular resistance index. Liver stiffness was inversely correlated with cardiac index. All 3 participants with hepatic nodules exhibiting decreased contrast uptake on delayed postcontrast imaging and increased nodule stiffness had biopsy-proven hepatocellular carcinoma.

CONCLUSION

The association between hepatic stiffness and fibrosis scores, Model for End-Stage Liver Disease scores, and γ-glutamyltransferase level suggests that MRE may be useful in detecting (and possibly quantifying) hepatic cirrhosis in patients after the Fontan operation. The correlation between stiffness and post-Fontan time interval, mean Fontan pressure, pulmonary vascular resistance index, and reduced cardiac index suggests a role for long-term hepatic congestion in creating these hepatic abnormalities. Magnetic resonance elastography was useful in detecting abnormal nodules ultimately diagnosed as hepatocellular carcinoma. The relationship between stiffness with advanced fibrosis and hepatocellular carcinoma provides a strong argument for additional study and broader application of MRE in these patients.

Transplantation in the Fontan patient

The failing Fontan circulation presents difficult treatment challenges. When Fontan revision and or intervention for treatable arrhythmias is not feasible, heart transplantation is the only therapeutic option. Particular challenges presented by these patients include limited ability to assess hemodynamics, complex anatomy, multiple prior procedures, and unique underlying pathologic states. These issues complicate the decision-making process for further surgical intervention verses transplantation. The pre-transplant evaluation, transplant operation, and post-operative management are more problematic for these patients compared with most patients undergoing transplantation. Consequently, failing Fontan patients constitute one of the highest risk heart transplant subsets.

Decision-Making for Surgery in the Management of Patients with Univentricular Heart

A series of technical refinements over the past 30 years, in combination with advances in perioperative management, have resulted in dramatic improvements in the survival of patients with univentricular heart. While the goal of single-ventricle palliation remains unchanged - normalization of the pressure and volume loads on the systemic ventricle, the strategies to achieve that goal have become more diverse. Optimal palliation relies on a thorough understanding of the changing physiology over the first years of life and the risks and consequences of each palliative strategy. This review describes how to optimize surgical decision-making in univentricular patients based on a current understanding of anatomy, physiology, and surgical palliation.