Systemic ventricular assist device support of the Fontan circulation yields promising outcomes: An analysis of The Society of Thoracic Surgeons Pedimacs and Intermacs Databases

Validating the Concept of Mechanical Circulatory Support with a Rotary Blood Pump in the Inferior Vena Cava in an Ovine Fontan Model

Right-sided mechanical support of the Fontan circulation by existing devices has been compounded by the cross-sectional design of vena cava anastomosis to both pulmonary arteries. Our purpose was to investigate whether increasing inferior vena cava (IVC) flow with a rotary blood pump in the IVC only in an ovine animal model of Fontan would lead to acceptable superior vena cava (SVC) pressure. To achieve this, a Fontan circulation was established in four female sheep by anastomosing the SVC to the main pulmonary artery (MPA) and by interposing a Dacron graft between the IVC and the MPA. A rotary blood pump was then introduced in the graft, and the effect of incremental flows was observed at increasing flow regimen. Additionally, to stimulate increased pulmonary resistance, the experience was repeated in each animal with the placement of a restrictive band on the MPA distally to the SVC and Dacron graft anastomosis. Circulatory support of IVC flow alone increased the systemic cardiac output significantly, both with and without banding, indicating the feasibility of mechanical support of the Fontan circulation by increasing the flow only in the inferior vena cava. The increase in SVC pressure remained within acceptable limits, indicating the potential effectiveness of this mode of support. The findings suggest that increasing the flow only in the inferior vena cava is a feasible method for mechanical support of the Fontan circulation, potentially leading to an increase in cardiac output with acceptable increases in superior vena cava pressure.

Durable ventricular assist device in adult patients with single ventricle: a systematic literature review

The worldwide experience with mechanical circulatory support in adult patients with single ventricle and Fontan palliation is limited. We aimed to see the outcomes in such patients on durable left ventricular assist device. We systematically reviewed the English language literature found on PubMed and Google Scholar, searching the terms "Fontan," "single ventricle," "ventricular assist device," "LVAD," and "mechanical circulatory support," and selected all individual cases with reported outcomes. We identified 4 patients on pulsatile left ventricular assist device, all of whom were successfully bridged to transplant, and 15 patients on continuous flow LVAD, age 25.9 ± 5.8, predominantly males. Mean time on LVAD support was 718.6 ± 616.5 days, and only 2 patients (13.3%) died. Durable left ventricular assist device support in adult patients with Fontan provides excellent results and should be used more frequently.

Mortality and morbidity after combined heart and liver transplantation in the failing Fontan: An updated dual center retrospective study

INTRODUCTION

As the adult Fontan population with Fontan associated liver disease continues to increase, more patients are being referred for transplantation, including combined heart and liver transplantation.

METHODS

We report updated mortality and morbidity outcomes after combined heart and liver transplant in a retrospective cohort series of 40 patients (age 14 to 49 years) with Fontan circulation across two centers from 2006-2022.

RESULTS

The 30-day, 1-year, 5-year and 10-year survival rate was 90%, 80%, 73% and 73% respectively. Sixty percent of patients met a composite comorbidity of needing either post-transplant mechanical circulatory support, renal replacement therapy or tracheostomy. Cardiopulmonary bypass time > 283 min (4.7 h) and meeting the composite comorbidity were associated with mortality by Kaplan Meier analysis.

CONCLUSION

Further study to mitigate early mortality and the above comorbidities as well as the high risk of bleeding and vasoplegia in this patient population is warranted.

Special Considerations for Mechanical Circulatory Support or Device Therapy in Adult Congenital Heart Disease Heart Failure

Heart failure has become the leading cause of mortality in adult congenital heart disease (ACHD) patients after the fifth decade of life. There is scanty evidence supporting the use of guideline-directed medical therapy in ACHD, especially in systemic right ventricle or single ventricle physiology. In complex patients, diagnosing heart failure and timely referral for advanced therapies are challenging. Mechanical circulatory support has been significantly developed over the past decade and has recently emerged as a feasible therapeutic option for these patients. This review summarizes current evidence of mechanical circulatory support in this population, its potential uses, and challenges.

Research Gaps in Pediatric Heart Failure: Defining the Gaps and Then Closing Them Over the Next Decade

Given the numerous opportunities and the wide knowledge gaps in pediatric heart failure, an international group of pediatric heart failure experts with diverse backgrounds were invited and tasked with identifying research gaps in each pediatric heart failure domain that scientists and funding agencies need to focus on over the next decade.

Outcomes after initial heart failure consultation in Fontan patients

BACKGROUND

Patients with Fontan failure are high-risk candidates for heart transplantation and other advanced therapies. Understanding the outcomes following initial heart failure consultation can help define appropriate timing of referral for advanced heart failure care.

METHODS

This is a survey study of heart failure providers seeing any Fontan patient for initial heart failure care. Part 1 of the survey captured data on clinical characteristics at the time of heart failure consultation, and Part 2, completed 30 days later, captured outcomes (death, transplant evaluation outcome, and other interventions). Patients were classified as "too late" (death or declined for transplant due to being too sick) and/or "care escalation" (ventricular assist device implanted, inotrope initiated, and/or listed for transplant), within 30 days. "Late referral" was defined as those referred too late and/or had care escalation.

RESULTS

Between 7/2020 and 7/2022, 77 Fontan patients (52% inpatient) had an initial heart failure consultation. Ten per cent were referred too late (6 were too sick for heart transplantation with one subsequent death, and two others died without heart transplantation evaluation, within 30 days), and 36% had care escalation (21 listed ± 5 ventricular assist device implanted ± 6 inotrope initiated). Overall, 42% were late referrals. Heart failure consultation < 1 year after Fontan surgery was strongly associated with late referral (OR 6.2, 95% CI 1.8-21.5, p=0.004).

CONCLUSIONS

Over 40% of Fontan patients seen for an initial heart failure consultation were late referrals, with 10% dying or being declined for transplant within a month of consultation. Earlier referral, particularly for those with heart failure soon after Fontan surgery, should be encouraged.

Single Center Experience With Durable Continuous Flow Single Ventricle Assist Device: A Viable Option in Fontan Circulatory Failure

Ventricular assist devices are increasingly used for patients with single ventricle physiology. We describe the use of durable, continuous flow, single ventricular assist device (SVAD) therapy in Fontan circulatory failure patients. Retrospective, single-center review of patients with Fontan circulation implanted with a SVAD between 2017 and 2022. Patient characteristics and outcomes were obtained by chart review. Nine patients underwent SVAD implantation (median age 24 years). Most patients had a total cavopulmonary connection; one had an atriopulmonary Fontan. Five patients had a systemic right ventricle. SVAD was most often utilized as bridge to candidacy (67%). Eight patients had at least moderate systemic ventricular systolic dysfunction. SVAD support continued for a median of 65 days (longest duration, 1,105 days) and one patient remains on support at time of submission. Of five patients discharged home, median length of stay after SVAD was 24 days. Six patients were transplanted (median 96 days from SVAD). Two patients died from pretransplant multisystem organ failure before transplant. All transplanted patients remain alive (median time since transplant 593 days). Continuous flow SVAD therapy can be effective for patients with Fontan circulatory failure and systolic dysfunction. Further studies should investigate feasibility and optimal SVAD timing with more advanced Fontan associated end-organ dysfunction.

Case report: Heart Mate III for systemic right ventricular support in a patient with hypoplastic left heart syndrome

Ventricular assist device implantation presents a possible bridge to heart transplantation for patients with failing Fontan physiology. However, evidence regarding outcome and possible pitfalls associated with the Fontan circulation is still insufficient. We describe the course of a 13-year-old male, who was born with hypoplastic left heart syndrome and underwent HeartMate III implantation due to refractory failure of the systemic right ventricle.

Updates in the management of congenital heart disease in adult patients

INTRODUCTION

Adults with congenital heart disease represent a highly diverse, ever-growing population. Optimal approaches to management of problems such as arrhythmia, sudden cardiac death, heart failure, transplant, application of advanced therapies and unrepaired shunt lesions are incompletely established. Efforts to strengthen our understanding of these complex clinical challenges and inform evidence-based practices are ongoing.

AREAS COVERED

This narrative review summarizes evidence underpinning current approaches to congenital heart disease management while highlighting areas requiring further investigation. A search of literature published in 'Medline,' 'EMBASE,' and 'PubMed' using search terms 'congenital heart disease,' 'arrhythmia,' 'sudden cardiac death,' 'heart failure,' 'heart transplant,' 'advanced heart failure therapy,' 'ventricular assist device (VAD),' 'mechanical circulatory support (MSC),' 'intracardiac shunt' and combinations thereof was undertaken.

EXPERT OPINION

Application of novel technologies in the diagnosis and management of arrhythmia has and will continue to improve outcomes in this population. Sudden death remains a prevalent problem with many persistent unknowns. Heart failure is a leading cause of morbidity and mortality. Improved access to specialist care, advanced therapies and cardiac transplant is needed. The emerging field of cardio-obstetrics will continue to define state-of-the-art care for the reproductive health of women with heart disease.

Comparing Long-Term Sequelae of the Systemic Right Ventricle: An Overview of Single Versus Biventricular Arrangements

Patients with systemic right ventricles (RV) are at risk for heart failure and sudden cardiac death. Contributing factors to RV dysfunction include increased afterload from the systemic circulation, coronary insufficiency, progressive tricuspid valve regurgitation, the presence of residual lesions after palliation and arrhythmias. While all patients with a systemic right ventricle (SRV) are vulnerable to heart failure, there are distinct differences between patients with congenital dextro-transpostion of the great arteries (d-TGA) repaired by atrial switch, unrepaired congenitally corrected transposition of the great arteries (cc-TGA) and single systemic right ventricles palliated with a Fontan operation. Herein, we explore both the similarities and differences in progression of heart failure by phenotype as well as both the advancements and limitations in treatment options by each type of SRV.

Hypoplastic Left Heart Syndrome Across the Lifespan: Clinical Considerations for Care of the Fetus, Child, and Adult

Hypoplastic left heart syndrome (HLHS) is the most common anatomic lesion in children born with single ventricle physiology and is characterized by the presence of a dominant right ventricle and a hypoplastic left ventricle along with small left-sided heart structures. Diagnostic subgroups of HLHS reflect the extent of inflow and outflow obstruction at the aortic and mitral valves, specifically stenosis or atresia. If left unpalliated, HLHS is a uniformly fatal lesion in infancy. Following introduction of the Norwood operation, early survival has steadily improved over the past four decades, mirroring advances in operative and peri-operative management as well as reflecting refinements in patient surveillance and interstage clinical care. Notably, survival following staged palliation has increased from 0% to a 5-year survival of 60-65% for children in some centres. Despite the prevalence of HLHS in childhood with relatively favourable surgical outcomes in contemporary series, this cohort is only now reaching early adult life and longer-term outcomes have yet to be elucidated. In this article we focus on contemporary clinical management strategies for patients with HLHS across the lifespan, from fetal to adult life. Nomenclature and diagnostic considerations are discussed and current literature pertaining to putative genetic etiologies is reviewed. The spectrum of fetal and pediatric interventional strategies, both percutaneous and surgical, are described. Clinical, patient-reported and neurodevelopmental outcomes of HLHS are delineated. Finally, note is made of current areas of clinical uncertainty and suggested directions for future research are highlighted.