Q&A: Considerations for sustaining advancement of durable mechanical circulatory support
Key takeaways:
- A new state-of-the-art review highlights advancements in mechanical circulatory support.
- Highlights include innovations in pump design and perioperative and long-term management of this patient population.
Since the implant of the first left ventricular assist device in 1994, the HF community observed significant technological innovation in durable mechanical circulatory support.
Advancements include innovations in pump design, perioperative and long-term management of patients on durable mechanical circulatory support.
In a new state-of-the-art review published in the Journal of Cardiac Failure, Aditi Nayak, MD, MS, advanced heart failure and transplant cardiologist at Baylor University Medical Center, along with colleagues and expert engineers, provided an overview of these advances.
Healio spoke with Nayak about what they mean for the future of advanced HF treatment.
Healio: Can you provide some background on the need for this state-of-the-art review?
Nayak: The American Heart Association estimates that of the 6 million Americans living with HF, about 10% of them — approximately 600,000 — have progression of HF to the point that conventional neurohormonal-based guideline-directed medical therapy no longer works, termed advanced HF.
Advanced HF can be treated in selected patients with heart transplantation and/or durable mechanical circulatory support. However, given the limited donor organ supply — indeed, there were only approximately 4,000 heart transplants performed in the U.S. in 2023 — durable mechanical circulatory support is the only truly scalable therapy for advanced HF. With the increasing prevalence of HF, now is the time to address opportunities for improvement in the durable mechanical circulatory support field to improve the patient experience and improve utilization of these lifesaving devices.
Currently available pumps require patients to be “tethered” to an external driveline, to commit to a lifetime of anticoagulation and to lead a “medicalized” lifestyle, with patients spending on average more than 1 in 5 days engaging in health care, according to a study in JACC: Heart Failure. There are limited options for small patients such as children and small women, those with complex anatomy, those with HF with preserved ejection fraction and restrictive cardiomyopathies and those in need of biventricular support. Additionally, these pumps are not automatically controlled and are associated with development of aortic insufficiency and right HF in the long term, which manifest as persistent HF-related symptoms. Motivated by these opportunities, engineers, clinicians and industry partners have made significant strides in innovating technological solutions to these remaining issues; and these emerging innovations are detailed in this review.
Healio: What is the main message you want clinicians who have patients with advanced HF to take away from this mechanical circulatory support review document?
Nayak: The field of durable mechanical circulatory support has undergone a transformative evolution over the past few decades, resulting in significant improvements in longevity and quality of life for patients with advanced HF. However, opportunities for further improvements in outcomes, and the overall patient experience remain. Ideally, these devices would be fully implantable, would be automatically controlled and would minimize need for anticoagulation. Reliable total artificial hearts for biventricular support that enable discharge to the home setting would be available; and peri- and postoperative management would be tailored to the individual patient phenotype. In this review, we summarize emerging technological innovations in these areas, highlighting important considerations to enable sustained evolution of the field.
However, enthusiasm for these innovations must be tempered by the long lead times for innovations to evolve from the early clinical stage to adoption in clinical practice, regulatory and reimbursement considerations. If and when scaled, efforts must be taken to not amplify preexisting inequities in access to therapy. There is a need to focus on collaborative cross-disciplinary efforts to further hone this technology. Areas that need particular focus from a clinical and translational research standpoint include understanding exercise physiology, and development of hemodynamic-related adverse events in patients on durable mechanical circulatory support.
Healio: Can you summarize some of the biggest advancements in durable mechanical circulatory support pump design?
Nayak: Some of the biggest advances in pump design that we have summarized in our paper include advances in transcutaneous energy transfer systems that utilize electromagnetic energy transfer to power the device and aim at eliminating the external driveline; novel left ventricular support devices that are in late preclinical or early clinical phases of trial aimed at addressing unmet clinical needs; and advances in development of total artificial heart devices.
Healio: What is the status of total artificial heart development?
Nayak: There is a need to develop reliable total artificial heart devices that can allow for long-term support in a home environment, for patients with biventricular HF. Limitations in development and implementation thus far have included difficulty transitioning implanted patients to the home environment, the large size of these devices limiting use in smaller patients and technical complexity of implantation. The SynCardia total artificial heart is presently the only available total artificial heart on the market; however, it has had issues with development of strokes, device torsion and high mortality, although at least partially explained by the high acuity of illness of patients in which these devices are implanted. Additionally, discharge to a home environment is not easy, due to the high noise levels produced by the pneumatic drive, which can be disrupting to some patients.
Motivated by these shortcomings, multiple total artificial heart companies such as BiVacor, Carmat and Realheart are developing total artificial hearts that seek to address these challenges.
The BiVacor device received early feasibility study approval from the FDA in December 2023 and the first implant is anticipated at one of nine U.S. centers in 2024 as part of a bridge-to-transplant study.
The Aeson total artificial heart is commercially available in Europe and is presently under early feasibility study trial in the U.S. for a bridge-to-transplant intent with the first cohort of three patients enrolled. Initiation of enrollment of the second cohort of seven patients is currently pending FDA approval. The Realheart total artificial heart is presently undergoing chronic animal studies.
Healio: How has perioperative management of patients requiring durable mechanical circulatory support changed?
Nayak: Innovations in the perioperative management of patients with LVAD, such as the use of advanced imaging coupled with virtual implantation and benchtop hybrid mock circulatory loops, have allowed currently available LVADs to be used in restrictive cardiomyopathies and congenital heart disease, with potential for use in the HFpEF population. When conscientiously performed with meticulous preoperative planning, implantation of mechanical circulatory support is safe and feasible in patients with a wide range of body and LV sizes. Although still not standardized or validated, patient-specific computational modeling may help individualize device selection and guide device settings to allow for optimal flow while reducing hemodynamic-related adverse events.
However, adoption of these technologies requires clinical, surgical and technical expertise that is currently concentrated in only a few quaternary centers across the country. This is a significant barrier to widespread implementation. Therefore, if and when scaled, concerted efforts should be taken to avoid amplifying preexisting inequities in access to therapy.
Healio: Can you summarize a few of the most significant advances in long-term management?
Nayak: The major opportunity from a patient-centric standpoint in long-term management of patients on durable mechanical circulatory support is a reduction in “medicalization” of patient lifestyle. There are several innovations that aim at addressing this that we highlight in our paper. One example is advances in remote and continuous hemodynamic monitoring based upon innovations in continuous access to internal pump signals. This may allow for real-time adjustments of pump speed and medications, reducing hospitalization and clinic visit burden.
We also detail recent research in patient-specific multiomics-based phenotyping, aimed at developing a precision medicine-based approach to reducing adverse events and promoting native myocardial recovery.
Advances in automatic pump speed control may allow optimization of pump performance to support native myocardial recovery while reducing risks for hemodynamic-related adverse events including aortic insufficiency and RV failure and suction events.
Healio: What challenges in advanced HF management with durable mechanical circulatory support remain and may not be potentially addressed by the innovations in this paper?
Nayak: No. 1 is the need to develop durable mechanical circulatory support devices for smaller-sized patients, including the pediatric population and smaller women. Innovation in this field has been slow, at least in part due to the limited funding available for these projects. In terms of pump design, some of the unique considerations include the need for a smaller device profile for anatomical fit into a smaller chest cavity, and generation of flow commensurate with body size. Although a few device companies, including Abbott and RealHeart, have committed efforts toward taking on these challenges, there is a need for a concerted effort on part of the mechanical circulatory support community of clinicians, engineers, investors and industry partners to develop device options for this vulnerable population.
No. 2 is the need to develop devices for the rapidly growing HFpEF population. A major challenge to development of these devices is the phenotypic and hemodynamic heterogeneity of this group of patients. Again, a few device companies have committed efforts toward taking on these challenges; but overall, a more concerted and collaborative approach on our part is necessary. One example is Pumpinheart’s device (PReduction pump), a durable partial support pump that is deployed across the mitral valve via a minimally invasive transcatheter approach, and functions as a diastolic support device. The prototypes have undergone in vitro, ex vivo and in vivo testing, but the results are yet not published.
Healio: Anything else you would like to add?
Nayak: This manuscript represents a true cross-disciplinary collaboration, written by expert engineers and clinicians from the U.S. and Europe. We need to break down the siloes between clinical medicine and engineering disciplines in the mechanical circulatory support field, to work jointly toward continued progress in improving the care of our advanced HF patients.
References:
- Chuzi S, et al. JACC Heart Fail. 2022;doi:10.1016/j.jchf.2022.01.011.
- Dual SA, et al. J Card Fail. 2024;doi:10.1016/j.cardfail.2024.01.011.
- Emerging technological innovations in durable mechanical circulatory Support (MCS) devices may reshape future experiences for patients. https://hfsa.org/emerging-technological-innovations-durable-mechanical-circulatory-support-mechanical circulatory support-devices-may-reshape. Published Feb. 29, 2024. Accessed March 13, 2024.
- Sidhu K, et al. Trends Cardiovasc Med. 2019;doi:10.1016/j.tcm.2019.05.013.
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