Ventricular Assist Device Therapy and Fontan: A Story of Supply and Demand

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.

A Novel Strategy for the Mechanical Subpulmonary Support in Failing Fontan Patients

Background The number of single ventricle patients undergoing Fontan palliation and surviving to adulthood worldwide has steadily increased in recent years. Nevertheless, the Fontan circulation is destined to fail. Ultimately, heart transplantation (HTx) remains the definitive treatment option. Due a shortage of organs, mechanical circulatory support in the form of ventricular assist devices (VADs) is widely used to bridge heart failure patients to HTx, but these devices have been mainly developed to address the needs of normal anatomies. A novel venous cannula has been developed as part of the EXCOR® VAD to provide subpulmonary support in these patients. Its clinical application is investigated in the “Registry to Assess the Safety and Feasibility of the Subpulmonary Support with the Novel Venous Cannula in Patients with Failing/Absence of the Right Heart” (RegiVe study, NCT04782232).

Methods RegiVe is a multicenter, international, observational, prospective, non-randomized registry aiming to collect the routine clinical data of up to 20 patients. The primary endpoints address device performance and safety, while the secondary endpoints target organ status and overall safety (according to the Interagency Registry for Mechanically Assisted Circulatory Support – INTERMACS – definitions). Data analysis will be performed by means of descriptive statistics.

Results RegiVe has received the favorable opinion of an independent ethics committee and enrollment has recently started.

Conclusion RegiVe is the first study evaluating the use of a medical device specifically developed for subpulmonary support of failing Fontan patients. The study will provide important insight and further information on this cohort and help to improve a dedicated VAD strategy.

Ventricular assist device for Fontan: who, when and why?

PURPOSE OF REVIEW

Since the advent of the Fontan palliation, survival of patients with univentricular congenital heart disease has increased significantly. These patients will, however, ultimately develop heart failure requiring advanced therapies such as heart transplantation. As wait times are long, mechanical circulatory support (MCS) is an attractive therapy, both for bridge to transplantation and destination therapy in patients not suitable for transplantation. This review aims to summarize current thinking about how to determine which patients would benefit from a ventricular assist device (VAD), the optimal time for implantation and which device should be considered.

RECENT FINDINGS

VAD implantation in end-stage Fontan is still in its infancy; however, case reports and research interest have increased extensively in the past few years. Mortality is significantly higher than in noncongenital heart disease patients. Implantation in patients with primarily systolic dysfunction is indicated, whereas patients with increased transpulmonary gradient may not benefit from a single-VAD solution. When possible, implantation should occur prior to clinical decompensation with evidence of end-organ damage, as outcomes at this point are worse.

SUMMARY

Fontan patients demonstrating signs of heart failure should be evaluated early and often for feasibility and optimal timing of VAD implantation. The frequency of this procedure will likely increase significantly in the future.

Chronic Ventricular Assist Device Support in Adult Congenital Heart Disease Patients: A Children's Hospital Perspective

With improvement in early surgical outcomes in patients with complex congenital heart disease, most patients are now expected to survive to adulthood. As adult congenital heart disease (ACHD) patients age, they are at risk of heart failure, which has become the leading cause of mortality in ACHD. Some who develop advanced heart failure may not be candidates for transplant, and chronic ventricular assist device (VAD) therapy may be the only means of survival. There is limited experience with chronic VAD therapy in ACHD patients, and the outcomes are not well delineated. We describe our center's experience with chronic VAD therapy in ACHD patients receiving care exclusively within our children's hospital.

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

BACKGROUND

Outcomes of ventricular assist device (VAD) support in patients with Fontan circulatory failure (or failing Fontan physiology) are largely unknown.

METHODS

We conducted a retrospective analysis of patients with a Fontan circulation who underwent VAD implant in the Society of Thoracic Surgeons Pedimacs and Intermacs Databases from September 19, 2012, to December 31, 2019.

RESULTS

We identified 55 Fontan patients who had undergone VAD implant with a median age at implantation of 10.2 years (interquartile range, 6.4-16.9 years) and weight, 26.8 kg (interquartile range, 17.7-53.8 years). More VADs were implanted in 2018-2019 than in 2012-2017 (28 vs 27; P = .01). The later era had higher pre-VAD glomerular filtration rate (101.1 ± 48.5 vs 71.2 ± 34.9; P = .02); there was no difference in Interagency Registry for Mechanically Assisted Circulatory Support profile (P = .69). Kaplan-Meier survival on device was 76% at 6 months with no difference by era. Competing outcomes demonstrated a positive outcome of 81% (alive on VAD, transplanted, or recovered) at 6 months, with 58% of mortality occurring during month 1. Median length of support was 3.8 months (interquartile range, 0.6-6.9 months). Five patients were supported for >1 year with no added mortality; the longest support time was 4 years, 7 months. Adverse event rates included pump thrombosis incidence of 4% (3.3 out of 100 patient-months), stroke 5.5% (1.4 out of 100 patient-months), gastrointestinal bleeding of 7% (2.6 out of 100 patient-months), and nongastrointestinal bleeding of 9% (2.3 out of 100 patient-months).

CONCLUSIONS

This is the largest reported analysis of systemic VAD support of Fontan patients. VAD support of the Fontan circulation is becoming more frequent. This analysis demonstrates that VAD use in this growing population can yield promising outcomes.

Transplantation and Arch Repair in Fontan 3 Years after HeartMate 3: Technical Considerations

We previously reported the first successful implantation of the Heartmate 3^TM in a Fontan patient. We now report his successful transplantation after 1,104 days of support, the longest reported bridge to transplantation of a Fontan patient. We describe our operative technique complicated by not only the Fontan anatomy and ventricular assist device (VAD) explanation but also a >10cm ascending and aortic arch aneurysm. Additionally, the post-transplant hemodynamics of this patient appear to demonstrate that effective VAD support may induce reversal of chronic effects of the failing Fontan circulation, which in this case was the elimination of his aorto-pulmonary collateral burden.