Long-term outcomes of patients bridged to recovery versus patients bridged to transplantation

Living biodrugs and how tissue source influences mesenchymal stem cell therapeutics for heart failure

In this editorial we comment on the article by Safwan M et al. We especially focused on the cardiac function restoration by the use of mesenchymal stem cells (MSCs) therapy for heart failure (HF), which has emerged as a new treatment approach as "Living Biodrugs". HF remains a significant clinical challenge due to the heart's inability to pump blood effectively, despite advancements in medical and device-based therapies. MSCs have emerged as a promising therapeutic approach, offering benefits beyond traditional treatments through their ability to modulate inflammation, reduce fibrosis, and promote endogenous tissue regeneration. MSCs can be derived from various tissues, including bone marrow and umbilical cord. Umbilical cord-derived MSCs exhibit superior expansion capabilities, making them an attractive option for HF therapy. Conversely, bone marrow-derived MSCs have been extensively studied for their potential to improve cardiac function but face challenges related to cell retention and delivery. Future research is focusing on optimizing MSC sources, enhancing differentiation and immune modulation, and improving delivery methods to overcome current limitations.

Discontinuation of Cardiac Devices at or Near an Adult Patient's End of Life

Advances in medical technology have begun to blur the lines between life and death as well as the lines between appropriate and inappropriate therapy. This review addresses the charged issue of the management of cardiac devices at or near the end of a patient's life, provides a summary of prior and current opinion with some historical context, and attempts to provide some modest guidance as to how to approach the various options to the patient's best advantage. Modalities to be addressed include indwelling electronic devices, the left ventricular assistance device, and extracorporeal mechanical oxygenation, and includes available outcome data as well as ethical analysis from a number of commentators. The expected further increase in technical sophistication of these devices is expected to render the various aspects of device deactivation more and more complex over the course of the next few years such that careful attention to and knowledge about this issue will continue to be more and more necessary.

Right heart failure after durable left ventricular assist device implantation

INTRODUCTION

Right heart failure (RHF) is a well-known complication after left ventricular assist device (LVAD) implantation and portends increased morbidity and mortality. Understanding the mechanisms and predictors of RHF in this clinical setting may offer ideas for early identification and aggressive management to minimize poor outcomes. A variety of medical therapies and mechanical circulatory support options are currently available for the management of post-LVAD RHF.

AREAS COVERED

We reviewed the existing definitions of RHF including its potential mechanisms in the context of durable LVAD implantation and currently available medical and device therapies. We performed a literature search using PubMed (from 2010 to 2023).

EXPERT OPINION

RHF remains a common complication after LVAD implantation. However, existing knowledge gaps limit clinicians' ability to adequately address its consequences. Early identification and management are crucial to reducing the risk of poor outcomes, but existing risk stratification tools perform poorly and have limited clinical applicability. This is an area ripe for investigation with the potential for major improvements in identification and targeted therapy in an effort to improve outcomes.

Advanced Heart Failure: Therapeutic Options and Challenges in the Evolving Field of Left Ventricular Assist Devices

Heart Failure is a chronic and progressively deteriorating syndrome that has reached epidemic proportions worldwide. Improved outcomes have been achieved with novel drugs and devices. However, the number of patients refractory to conventional medical therapy is growing. These advanced heart failure patients suffer from severe symptoms and frequent hospitalizations and have a dismal prognosis, with a significant socioeconomic burden in health care systems. Patients in this group may be eligible for advanced heart failure therapies, including heart transplantation and chronic mechanical circulatory support with left ventricular assist devices (LVADs). Heart transplantation remains the treatment of choice for eligible candidates, but the number of transplants worldwide has reached a plateau and is limited by the shortage of donor organs and prolonged wait times. Therefore, LVADs have emerged as an effective and durable form of therapy, and they are currently being used as a bridge to heart transplant, destination lifetime therapy, and cardiac recovery in selected patients. Although this field is evolving rapidly, LVADs are not free of complications, making appropriate patient selection and management by experienced centers imperative for successful therapy. Here, we review current LVAD technology, indications for durable MCS therapy, and strategies for timely referral to advanced heart failure centers before irreversible end-organ abnormalities.

Incidence, Outcomes, and Opportunity for Left Ventricular Assist Device Weaning for Myocardial Recovery

BACKGROUND

Myocardial recovery occurs in patients with advanced heart failure on left ventricular assist device (LVAD) support, but there is the premise that it is rare with uncertain results.

OBJECTIVES

The goal of this study was to investigate the incidence and consequence of LVAD explant after myocardial recovery.

METHODS

Using the United Network for Organ Sharing registry, LVAD implants in the United States between 2005 and 2020 were tracked until death, transplantation, or explant for myocardial recovery. The cohort undergoing explant was followed up for heart failure relapse (defined as relisting followed by delisting due to death, being too ill, or transplantation; or second durable LVAD implant).

RESULTS

Of 15,728 LVAD implants, 126 patients underwent explant for recovery, which only occurred in 55 (38%) of 145 implanting centers. The crude cumulative incidence was 0.7% at 2 years, whereas the incidence reached 4.7% among designated centers in the selected young nonischemic cohort. Of 126 explanted patients, 76 (60%) were subsequently delisted for sustained recovery. Heart failure relapsing had a relatively higher hazard in the early phase, with a 30-day incidence of 6% (7 of 126) but tapered following with the freedom rate of 72.5% at 4 years.

CONCLUSIONS

In the United States, LVAD explant for myocardial recovery was underutilized, leading to a very low incidence at the national level despite a realistic rate being achieved in designated centers for selected patients. With follow-up extending up to 4 years after explant, more than one-half were successfully removed and stayed off the waitlist, and approximately 70% were free from heart failure relapse events.

Cardiological Challenges Related to Long-Term Mechanical Circulatory Support for Advanced Heart Failure in Patients with Chronic Non-Ischemic Cardiomyopathy

Long-term mechanical circulatory support by a left ventricular assist device (LVAD), with or without an additional temporary or long-term right ventricular (RV) support, is a life-saving therapy for advanced heart failure (HF) refractory to pharmacological treatment, as well as for both device and surgical optimization therapies. In patients with chronic non-ischemic cardiomyopathy (NICM), timely prediction of HF's transition into its end stage, necessitating life-saving heart transplantation or long-term VAD support (as a bridge-to-transplantation or destination therapy), remains particularly challenging, given the wide range of possible etiologies, pathophysiological features, and clinical presentations of NICM. Decision-making between the necessity of an LVAD or a biventricular assist device (BVAD) is crucial because both unnecessary use of a BVAD and irreversible right ventricular (RV) failure after LVAD implantation can seriously impair patient outcomes. The pre-operative or, at the latest, intraoperative prediction of RV function after LVAD implantation is reliably possible, but necessitates integrative evaluations of many different echocardiographic, hemodynamic, clinical, and laboratory parameters. VADs create favorable conditions for the reversal of structural and functional cardiac alterations not only in acute forms of HF, but also in chronic HF. Although full cardiac recovery is rather unusual in VAD recipients with pre-implant chronic HF, the search for myocardial reverse remodelling and functional improvement is worthwhile because, for sufficiently recovered patients, weaning from VADs has proved to be feasible and capable of providing survival benefits and better quality of life even if recovery remains incomplete. This review article aimed to provide an updated theoretical and practical background for those engaged in this highly demanding and still current topic due to the continuous technical progress in the optimization of long-term VADs, as well as due to the new challenges which have emerged in conjunction with the proof of a possible myocardial recovery during long-term ventricular support up to levels which allow successful device explantation.

Durable Mechanical Circulatory Support: JACC Scientific Statement

Despite advances in medical therapy for patients with stage C heart failure (HF), survival for patients with advanced HF is <20% at 5 years. Durable left ventricular assist device (dLVAD) support is an important treatment option for patients with advanced HF. Innovations in dLVAD technology have reduced the risk of several adverse events, including pump thrombosis, stroke, and bleeding. Average patient survival is now similar to that of heart transplantation at 2 years, with 5-year dLVAD survival now approaching 60%. Unfortunately, greater adoption of dLVAD therapy has not been realized due to delayed referral of patients to advanced HF centers, insufficient clinician knowledge of contemporary dLVAD outcomes (including gains in quality of life), and deprioritization of patients with dLVAD support waiting for heart transplantation. Despite these challenges, novel devices are on the horizon of clinical investigation, offering smaller size, permitting less invasive surgical implantation, and eliminating the percutaneous lead for power supply.

Left ventricular assist device thrombosis in the setting of supratherapeutic international normalized ratio (INR) and bleeding

A 71-year-old female with heart failure who underwent left ventricular assist device (LVAD) placement presented for evaluation of low hemoglobin and dark stools. She also had leg pain, numbness, and weakness for which she was taking ibuprofen. She was found to have a gastrointestinal bleed, INR of 4.3, and arterial thrombi in the left leg. She was stabilized, had her anticoagulation held, and underwent mechanical thrombectomy. On hospital day 6, LVAD interrogation revealed signs of thrombosis, while subsequent labs revealed a persistently supratherapeutic INR of 5.2. The patient had the LVAD removed and underwent further hematologic workup. Her platelets remained normal throughout the admission, indicating this was not acute disseminated intravascular coagulation (DIC), thrombotic thrombocytopenic purpura (TTP), or heparin induced thrombocytopenia (HIT). Echocardiography identified it as a primary thrombus. This case illustrates the importance of appropriate anticoagulation to balance the bleeding risk with the risk of thrombi, as well as the importance of maintaining high suspicion for LVAD thrombosis regardless of INR.

Myocardial recovery following left ventricular assist device implantation

Durable left ventricular assist devices (LVADs) have consistently shown improved mortality and morbidity in patients with end-stage heart failure. Select patients with LVADs may experience significant enough myocardial recovery after device implantation to allow for explantation or decommissioning. While earlier trials suggested a high incidence of recovery, real-world clinical data have demonstrated this to be a much rarer phenomenon. Whether or not patients experience recovery, practices such as speed optimization and usage of guideline-directed medical therapy can improve patient outcomes.

Clinical myocardial recovery in advanced heart failure with long term left ventricular assist device support

Left ventricular assist-device (LVAD) implantation is a life-saving therapy for patients with advanced heart failure (HF). With chronic unloading and circulatory support, LVAD-supported hearts often show significant reverse remodeling at the structural, cellular and molecular level. However, translation of these changes into meaningful cardiac recovery allowing LVAD explant is lagging. Part of the reason for this discrepancy is lack of anticipation and hence promotion and evaluation for recovery post LVAD implant. There is additional uncertainty about the long-term course of HF following LVAD explant. In selected patients, however, guided by the etiology of HF, duration of disease and other clinical factors, significant functional improvement and LVAD explantation with long-term freedom from recurrent HF events has been demonstrated to be feasible in a reproducible manner. The identified predictors of myocardial recovery suggest that the elective therapeutic use of potentially less invasive VADs for reversal of HF earlier in the disease process is a future goal that warrants further investigation. Hence, it is prudent to develop and implement tools to predict HF reversibility prior to LVAD implant, optimize unloading-promoted recovery with guideline directed medical therapy and monitor for myocardial improvement. This review article summarizes the clinical aspects of myocardial recovery and together with its companion review article focused on the biological aspects of recovery, they aim to provide a useful framework for clinicians and investigators.

LVAD as a Bridge to Remission from Advanced Heart Failure: Current Data and Opportunities for Improvement

Left ventricular assist devices (LVADs) are an established treatment modality for advanced heart failure (HF). It has been shown that through volume and pressure unloading they can lead to significant functional and structural cardiac improvement, allowing LVAD support withdrawal in a subset of patients. In the first part of this review, we discuss the historical background, current evidence on the incidence and assessment of LVAD-mediated cardiac recovery, and out-comes including quality of life after LVAD support withdrawal. In the second part, we discuss current and future opportunities to promote LVAD-mediated reverse remodeling and improve our pathophysiological understanding of HF and recovery for the benefit of the greater HF population.

Left Ventricular Assist Device as a Bridge to Recovery: Single Center Experience of Successful Device Explantation

Continuous-flow left ventricular assist devices (CF-LVAD) have been shown to enhance reverse remodeling and myocardial recovery in certain patients allowing for device removal. We sought to analyze the characteristics and describe outcomes of patients who underwent CF-LVAD explantation at a large academic center. We retrospectively identified all patients who underwent CF-LVAD explants due to recovery from 2006 to 2019. Patient baseline characteristics and data on pre- and postexplant evaluation were collected and analyzed. Of 421 patients who underwent CF-LVAD implantation, 13 underwent explantation (3.1%). Twelve HeartMate II and one HeartWare LVAD were explanted. All patients had nonischemic cardiomyopathy. Median time from heart failure diagnosis to LVAD implant was 12 months (interquartile range [IQR], 2-44) and the median time supported on LVAD was 22 months (IQR, 11-28). Two patients died within 30 days of explant. Three additional patients died during the follow-up period and all were noted to be nonadherent to medical therapy. After a mean follow-up duration of 5 years, overall survival was 52%. Mean pre-explant ejection fraction was 49%, which decreased at most recent follow-up to 32%. Mean pre-explant left ventricular internal diameter in diastole (LVIDD) was 4.37 cm and increased to 5.52 cm at most recent follow-up. Continuous-flow left ventricular assist device explantation is feasible and safe in select patients.

LVAD decommissioning for myocardial recovery: Long-term ventricular remodeling and adverse events

BACKGROUND

Left ventricular assist devices (LVADs) mechanically unload the heart and coupled with neurohormonal therapy can promote reverse cardiac remodeling and myocardial recovery. Minimally invasive LVAD decommissioning with the device left in place has been reported to be safe over short-term follow-up. Whether device retention reduces long-term safety, or sustainability of recovery is unknown.

METHODS

This is a dual-center retrospective analysis of patients who had achieved responder status (left ventricular ejection fraction, LVEF ≥40% and left ventricular internal diastolic diameter, LVIDd ≤6.0 cm) and underwent elective LVAD decommissioning for myocardial recovery from May 2010 to January 2020. All patients had outflow graft closure and driveline resection with the LVAD left in place. Emergent LVAD decommissioning for an infection or device thrombosis was excluded. Patients were followed with serial echocardiography for up to 3-years. The primary clinical outcome was survival free of heart failure hospitalization, LVAD reimplantation, or transplant.

RESULTS

During the study period 515 patients received an LVAD and 29 (5.6%) achieved myocardial recovery, 12 patients underwent total device explantation or urgent device decommissioning, 17 patients underwent elective LVAD decommissioning, and were included in the analysis. Median age of patients at LVAD implantation was 42 years (interquartile range, IQR: 25-54 years), all had a nonischemic cardiomyopathy, and 5 (29%) were female. At LVAD implantation, median LVEF was 10% (IQR: 5%-15%), and LVIDd 6.6 cm (IQR: 5.8-7.1 cm). There were 11 hydrodynamically levitated centrifugal-flow (65%), and 6 axial-flow LVADs (35%). The median duration of LVAD support before decommissioning was 28.7 months (range 13.5-36.2 months). As compared to the turndown study parameters, 1-month post-decommissioning, median LVEF decreased from 55% to 48% (p = 0.03), and LVIDd increased from 4.8 cm to 5.2 cm (p = 0.10). There was gradual remodeling until 6 months, after which there was no statistical difference on follow-up through 3-years (LVEF 42%, LVIDd 5.6 cm). Recurrent infections affected 41% of patients leading to 3 deaths and 1 complete device explant. Recurrent HF occurred in 1 patient who required a transplant. Probability of survival free of HF, LVAD, or transplant was 94% at 1-year, and 78% at 3-years.

CONCLUSIONS

LVAD decommissioning for myocardial recovery was associated with excellent long-term survival free from recurrent heart failure and preservation of ventricular size and function up to 3-years. Reducing the risk of recurrent infections, remains an important therapeutic goal for this management strategy.

Antiplatelet and Anticoagulant Strategies Following Left Ventricular Assist Device (LVAD) Explantation or Decommissioning: A Scoping Review of the Literature

Mechanical circulatory support using left ventricular assist devices (LVADs) has transformed management of patients with end-stage heart failure with more patients on LVAD therapy surviving long enough to necessitate either device explantation or decommissioning. Usually, there is foreign material retained following these procedures that requires maintaining antiplatelet and/or anticoagulant therapy. However, there is no consensus on optimal management of antiplatelet and anticoagulant therapy following LVAD explantation or decommissioning. We conducted a scoping review of antiplatelet and anticoagulation strategies, searching EMBASE, PubMed and CENTRAL. A total of 15 case reports and series encompassing 38 patient cases were found that met inclusion criteria. There was a heterogeneity of LVAD types and techniques used for explantation and decommissioning. Most reports identified in our review maintained patients on a vitamin K antagonist for at least 3 months post-explantation or decommissioning with or without concomitant antiplatelet therapy with low-dose aspirin. However, there was no single agreed-upon optimal strategy for antiplatelet and anticoagulant use post-procedure. Factors such as the degree of foreign material retained following device explantation or decommissioning and whether there is another indication for anticoagulation or antiplatelet use must be considered. A lack of overall consensus indicates that more studies are needed in this area to establish definitive guidelines around antiplatelet and anticoagulant therapy following LVAD explantation or decommissioning.

Continuous-Flow Left Ventricular Assist Device Explantation After More Than 5 Years of Circulatory Support and Ventricular Reconditioning

Continuous-flow left ventricular assist devices have proved to be effective, durable, life-saving tools in patients with end-stage heart failure. However, because of the risks associated with mechanical circulatory support (including stroke, infection, gastrointestinal bleeding, and device malfunction), the optimal goal of device therapy is myocardial recovery and device removal. Ventricular reconditioning and pump explantation after continuous-flow support have been reported; however, little is known about variables that govern the pace and degree of myocardial response in patients who experience such recovery. We describe our long-term pump-weaning strategy for a 25-year-old man who had a continuous-flow device implanted and then needed more than 5 years of support from it before developing cardiac reserve sufficient to enable pump explantation. To our knowledge, this is the longest period of uninterrupted continuous-flow device support to end in successful pump deactivation and a return to medical therapy. This case highlights the importance of actively and persistently pursuing a device-weaning strategy in all patients who need left ventricular assist device therapy.

Weaning from ventricular assist device support after recovery from left ventricular failure with or without secondary right ventricular failure

Although complete myocardial recovery after ventricular assist device (VAD) implantation is rather seldom, systematic search for recovery is worthwhile because for recovered patients weaning from VADs is feasible and can provide survival benefits with long-term freedom from heart failure (HF) recurrence, even if a chronic cardiomyopathy was the primary cause for the drug-refractory HF necessitating left ventricular (LVAD) or biventricular support (as bridge-to-transplantation or definitive therapy) and even if recovery remains incomplete. LVAD patients explanted for myoacardial recovery compared to those transplanted from LVAD support showed similar survival rates and a significant proportion of explanted patients can achieve cardiac and physical functional capacities that are within the normal range of healthy controls. In apparently sufficiently recovered patients, a major challenge remains still the pre-explant prediction of the weaning success which is meanwhile reliably possible for experienced clinicians. In weaning candidates, the combined use of certain echocardiography and right heart catheterization parameters recorded before VAD explantation can predict post-weaning cardiac stability with good accuracy. However, in the absence of standardization or binding recommendations, the protocols for assessment of native cardiac improvement and also the weaning criteria differ widely among centers. Currently there are still only few larger studies on myocardial recovery assessment after VAD implantation. Therefore, the weaning practice relies mostly on small case series, local practice patterns, and case reports, and the existing knowledge, as well as the partially differing recommendations which are based mainly on expert opinions, need to be periodically systematised. Addressing these shortcomings, our review aims to summarize the evidence and expert opinion on the evaluation of cardiac recovery during mechanical ventricular support by paying special attention to the reliability of the methods and parameters used for assessment of myocardial recovery and the challenges met in both evaluation of recovery and weaning decision making.

Prospective Multicenter Study of Myocardial Recovery Using Left Ventricular Assist Devices (RESTAGE-HF [Remission from Stage D Heart Failure])

Background:

Left ventricular assist device (LVAD) unloading and hemodynamic support in patients with advanced chronic heart failure can result in significant improvement in cardiac function allowing LVAD removal; however, the rate of this is generally considered to be low. This prospective multicenter nonrandomized study (RESTAGE-HF [Remission from Stage D Heart Failure]) investigated whether a protocol of optimized LVAD mechanical unloading, combined with standardized specific pharmacological therapy to induce reverse remodeling and regular testing of underlying myocardial function, could produce a higher incidence of LVAD explantation.

Methods:

Forty patients with chronic advanced heart failure from nonischemic cardiomyopathy receiving the Heartmate II LVAD were enrolled from 6 centers. LVAD speed was optimized with an aggressive pharmacological regimen, and regular echocardiograms were performed at reduced LVAD speed (6000 rpm, no net flow) to test underlying myocardial function. The primary end point was the proportion of patients with sufficient improvement of myocardial function to reach criteria for explantation within 18 months with sustained remission from heart failure (freedom from transplant/ventricular assist device/death) at 12 months.

Results:

Before LVAD, age was 35.1±10.8 years, 67.5% were men, heart failure mean duration was 20.8±20.6 months, 95% required inotropic and 20% temporary mechanical support, left ventricular ejection fraction was 14.5±5.3%, end-diastolic diameter was 7.33±0.89 cm, end-systolic diameter was 6.74±0.88 cm, pulmonary artery saturations were 46.7±9.2%, and pulmonary capillary wedge pressure was 26.2±7.6 mm Hg. Four enrolled patients did not undergo the protocol because of medical complications unrelated to the study procedures. Overall, 40% of all enrolled (16/40) patients achieved the primary end point, P <0.0001, with 50% (18/36) of patients receiving the protocol being explanted within 18 months (pre-explant left ventricular ejection fraction, 57±8%; end-diastolic diameter, 4.81±0.58 cm; end-systolic diameter, 3.53±0.51 cm; pulmonary capillary wedge pressure, 8.1±3.1 mm Hg; pulmonary artery saturations 63.6±6.8% at 6000 rpm). Overall, 19 patients were explanted (19/36, 52.3% of those receiving the protocol). The 15 ongoing explanted patients are now 2.26±0.97 years after explant. After explantation survival free from LVAD or transplantation was 90% at 1-year and 77% at 2 and 3 years.

Conclusions:

In this multicenter prospective study, this strategy of LVAD support combined with a standardized pharmacological and cardiac function monitoring protocol resulted in a high rate of LVAD explantation and was feasible and reproducible with explants occurring in all 6 participating sites.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01774656.

The Partial Support of the Left Ventricular Assist Device Shifts the Systemic Cardiac Output Curve Upward in Proportion to the Effective Left Ventricular Ejection Fraction in Pressure-Volume Loop

Left ventricular assist device (LVAD) has been saving many lives in patients with severe left ventricular (LV) failure. Recently, a minimally invasive transvascular LVAD such as Impella enables us to support unstable hemodynamics in severely ill patients. Although LVAD support increases total LV cardiac output (CO_TLV) at the expense of decreases in the native LV cardiac output (CO_NLV), the underlying mechanism determining CO_TLV remains unestablished. This study aims to clarify the mechanism and develop a framework to predict CO_TLV under known LVAD flow (CO_LVAD). We previously developed a generalized framework of circulatory equilibrium that consists of the integrated CO curve and the VR surface as common functions of right atrial pressure (P_RA) and left atrial pressure (P_LA). The intersection between the integrated CO curve and the VR surface defines circulatory equilibrium. Incorporating LVAD into this framework indicated that LVAD increases afterload, which in turn decreases CO_NLV. The total LV cardiac output (CO_TLV) under LVAD support becomes CO_TLV = CO_NLV+EF_e · CO_LVAD, where EF_e is effective ejection fraction, i.e., E_es/(E_es+E_a). E_es and E_a represent LV end-systolic elastance (E_es) and effective arterial elastance (E_a), respectively. In other words, LVAD shifts the total LV cardiac output curve upward by EF_e · CO_LVAD. In contrast, LVAD does not change the VR surface or the right ventricular CO curve. In six anesthetized dogs, we created LV failure by the coronary ligation of the left anterior descending artery and inserted LVAD by withdrawing blood from LV and pumping out to the femoral artery. We determined the parameters of the CO curve with a volume-change technique. We then changed the CO_LVAD stepwise from 0 to 70–100 ml/kg/min and predicted hemodynamics by using the proposed circulatory equilibrium. Predicted CO_TLV, P_RA, and P_LA for each step correlated well with those measured (SEE; 2.8 ml/kg/min 0.17 mmHg, and 0.65 mmHg, respectively, r²; 0.993, 0.993, and 0.965, respectively). The proposed framework quantitatively predicted the upward-shift of the total CO curve resulting from the synergistic effect of LV systolic function and LVAD support. The proposed framework can contribute to the safe management of patients with LVAD.

A new pathophysiology in heart failure patients

In the treatment of patients with severe heart failure, left ventricle assist device plays an important role, especially as a destination therapy. Nevertheless, even in successful cases, patients' progressive weaning is rarely taken into consideration. The recovery of more physiological circulation conditions is not a main goal. This hypothesis is discussed in this article.

Long-term support by left ventricular assist device for arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a heart muscle disorder characterized by right ventricular enlargement, right heart failure (HF), and ventricular arrhythmias which lead to sudden death especially in young adults. Current recommendations for management of patients with ARVC are antiarrhythmic medications, catheter ablation, and implantable cardioverter defibrillator therapy to prevent sudden cardiac death. However, despite these treatments, few patients suffer from recurrent ventricular arrhythmias or HF unresponsive to conventional management. Heart transplantation (HTx) is a preferred treatment for these cases, but because of a persistent donor heart shortage in Japan, ventricular assist device (VAD) support has become an important option for a management of the end-stage ARVC. Previous articles reported 4 cases of a successful management by left ventricular assist device (LVAD), but the longest interval of LVAD support was only 333 days. We present 3 cases of ARVC patients who were successfully managed by LVAD implantation for more than a year. These 3 cases are unconventional examples of ARVC patients, considering the nature of the disease. The novelty of these cases should be taken in the context of the extremely long waiting period for HTx in Japan.

Recovery of failing hearts by mechanical unloading: Pathophysiologic insights and clinical relevance

By reduction of ventricular wall-tension and improving the blood supply to vital organs, ventricular assist devices (VADs) can eliminate the major pathophysiological stimuli for cardiac remodeling and even induce reverse remodeling occasionally accompanied by clinically relevant reversal of cardiac structural and functional alterations allowing VAD explantation, even if the underlying cause for the heart failure (HF) was dilated cardiomyopathy. Accordingly, a tempting potential indication for VADs in the future might be their elective implantation as a therapeutic strategy to promote cardiac recovery in earlier stages of HF, when the reversibility of morphological and functional alterations is higher. However, the low probability of clinically relevant cardiac improvement after VAD implantation and the lack of criteria which can predict recovery already before VAD implantation do not allow so far VAD implantations primarily designed as a bridge to cardiac recovery. The few investigations regarding myocardial reverse remodeling at cellular and sub-cellular level in recovered patients who underwent VAD explantation, the differences in HF etiology and pre-implant duration of HF in recovered patients and also the differences in medical therapy used by different institutions during VAD support make it currently impossible to understand sufficiently all the biological processes and mechanisms involved in cardiac improvement which allows even VAD explantation in some patients. This article aims to provide an overview of the existing knowledge about VAD-promoted cardiac improvement focusing on the importance of bench-to-bedside research which is mandatory for attaining the future goal to use long-term VADs also as therapy-devices for reversal of chronic HF.

Outcomes from a recovery protocol for patients with continuous-flow left ventricular assist devices

BACKGROUND

In this retrospective analysis we evaluated a standardized echocardiographic assessment and an invasive technique for patient selection for successful continuous-flow left ventricular assist device (CF-LVAD) explantation.

METHODS

Inclusion criteria for LVAD recovery assessment were: clinically stable condition; LVAD support for >6 months; physical activity; normal echocardiography findings; and no more than mild valvular disease and aortic valve opening. In a second step, echocardiography was performed under CF-LVAD reduction and stop conditions (PStopE). In the third step, patients who presented with stable parameters underwent right heart catheterization under CF-LVAD stoppage and occlusion of the outflow graft with a balloon catheter. Criteria for explantation were normal pulmonary artery pressure and pulmonary capillary wedge pressure <16 mmHg.

RESULTS

Thirty-three of 424 patients entered the second step of evaluation and 20 entered the third step. Fourteen presented positive results and the pump was successfully explanted. The PCWP at baseline was 8.5 (2.8) mmHg in the explantation group and 10.6 (2.8) mmHg in the non-explantation group (p = 0.105). It increased to 10.9 (3.0) mmHg vs 20.8 (4.9) mmHg under outflow graft occlusion. The wedge pressure was significantly higher in the non-explantation group (p < 0.001). Median duration of follow-up after explantation was 9.74 (interquartile range 4.3 to 20.60) months, with survival of 93%.

CONCLUSIONS

The protocol presented is feasible and safe. The criteria applied provide good patient selection for sustained mid-term myocardial recovery after LVAD explantation.

A bridge from HeartMate XVE to HeartMate 3

Cardiac recovery after left ventricular assist device (LVAD) implantation is rare. Recurrent heart failure after device explantation is also rare. We describe a patient who is the recipient of a third-generation LVAD due to recurrent heart failure nearly one decade after successfully being bridged to recovery after implantation of a first-generation LVAD.

Construction of an Apical Plug for Explantation of HeartWare HVAD Left Ventricular Assist Device

Utilization of a left ventricular assist device as a bridge to myocardial recovery is an established therapy for acute systolic heart failure. However, device removal can present a technical challenge, with no clear consensus on preferred method. In this case report, we describe a complex patient who underwent successful explantation of a left ventricular assist device using an intraoperatively constructed apical plug. This method utilizes inexpensive and easily accessible materials, minimizes ventricular distortion during device removal, and preserves the ventricular sewing ring for future reimplantation.

Left Ventricular Assist Device as a Bridge to Recovery for Patients With Advanced Heart Failure

BACKGROUND

Left ventricular assist devices (LVADs) have been used as an effective therapeutic option in patients with advanced heart failure, either as a bridge to transplantation, as destination therapy, or in some patients, as a bridge to recovery.

OBJECTIVES

This study evaluated whether patients undergoing an LVAD bridge-to-recovery protocol can achieve cardiac and physical functional capacities equivalent to those of healthy controls.

METHODS

Fifty-eight male patients-18 implanted with a continuous-flow LVAD, 16 patients with LVAD explanted (recovered patients), and 24 heart transplant candidates (HTx)-and 97 healthy controls performed a maximal graded cardiopulmonary exercise test with continuous measurements of respiratory gas exchange and noninvasive (rebreathing) hemodynamic data. Cardiac function was represented by peak exercise cardiac power output (mean arterial blood pressure × cardiac output) and functional capacity by peak exercise O₂ consumption.

RESULTS

All patients demonstrated a significant exertional effort as demonstrated with the mean peak exercise respiratory exchange ratio >1.10. Peak exercise cardiac power output was significantly higher in healthy controls and explanted LVAD patients compared with other patients (healthy 5.35 ± 0.95 W; explanted 3.45 ± 0.72 W; LVAD implanted 2.37 ± 0.68 W; and HTx 1.31 ± 0.31 W; p < 0.05), as was peak O₂ consumption (healthy 36.4 ± 10.3 ml/kg/min; explanted 29.8 ± 5.9 ml/kg/min; implanted 20.5 ± 4.3 ml/kg/min; and HTx 12.0 ± 2.2 ml/kg/min; p < 0.05). In the LVAD explanted group, 38% of the patients achieved peak cardiac power output and 69% achieved peak O₂ consumption within the ranges of healthy controls.

CONCLUSIONS

The authors have shown that a substantial number of patients who recovered sufficiently to allow explantation of their LVAD can even achieve cardiac and physical functional capacities nearly equivalent to those of healthy controls.

Prediction of hemodynamics under left ventricular assist device

Left ventricular assist device (LVAD) saves lives in patients with severe left ventricular (LV) failure. However, predicting how much LVAD boosts total cardiac output (CO) remains difficult. This study aimed to develop a framework to quantitatively predict the impact of LVAD on hemodynamics. We adopted the circulatory equilibrium framework and incorporated LVAD into the integrated CO curve to derive the circulatory equilibrium. In anesthetized dogs, we ligated left coronary arteries to create LV failure and inserted a centrifugal pump as LVAD. Using CO and right (PRA) and left atrial pressure (PLA) measured before LVAD support, we predetermined the stressed volume (V) and logarithmic slope of right heart CO curve (SR). Next, we initiated LVAD at maximum level and then decreased LVAD flow stepwise while monitoring hemodynamic changes. We predicted LVAD-induced CO and PRA for given PLA from the predetermined SR and V and compared with those measured experimentally. The predicted CO [ r2 = 0.907, SE of estimate (SEE) = 5.59 ml·min−1·kg−1, P < 0.001] and PRA ( r2 = 0.967, SEE = 0.307 mmHg, P < 0.001) matched well with measured values indicating the validity of the proposed framework. We further conducted simulation using the validated framework to analyze the impact of LVAD on PRA under various right ventricular (RV) functions. It indicated that PRA is relatively insensitive to changes in RV end-systolic elastance or pulmonary arterial resistance, but sensitive to changes in V. In conclusion, the circulatory equilibrium framework predicts quantitatively the hemodynamic impact of LVAD. This knowledge would contribute to safe management of patients with LV failure undergoing LVAD implantation.

NEW & NOTEWORTHY Hemodynamic response to left ventricular assist device (LVAD) has not been quantitatively investigated. This is the first report of quantitative prediction of the hemodynamics on LVAD using circulatory equilibrium framework. The validated framework allows us to simulate the impact of LVAD on right atrial pressure under various right ventricular functions.

DURABLE MECHANICAL CIRCULATION SUPPORT AS AN ALTERNATIVE TO HEART TRANSPLANTATION

In the review a comparative analysis of the treatment of end-stage chronic heart failure using heart transplantation and durable mechanical circulatory is conducted. It shows the main advantages and limitations of heart transplantation and the prospects of application of durable mechanical circulatory support technology. The main directions of this technology, including two-stage heart transplant (bridge to transplant – BTT), assisted circulation for myocardial recovery (bridge to recovery – BTR) and implantation of an auxiliary pump on a regular basis (destination therapy, DT). 

Advanced Strategies for End-Stage Heart Failure: Combining Regenerative Approaches with LVAD, a New Horizon?

Despite the improved treatment of cardiovascular diseases, the population with end-stage heart failure (HF) is progressively growing. The scarcity of the gold standard therapy, heart transplantation, demands novel therapeutic approaches. For patients awaiting transplantation, ventricular-assist devices have been of great benefit on survival. To allow explantation of the assist device and obviate heart transplantation, sufficient and durable myocardial recovery is necessary. However, explant rates so far are low. Combining mechanical circulatory support with regenerative therapies such as cell (-based) therapy and biomaterials might give rise to improved long-term results. Although synergistic effects are suggested with mechanical support and stem cell therapy, evidence in both preclinical and clinical setting is lacking. This review focuses on advanced and innovative strategies for the treatment of end-stage HF and furthermore appraises clinical experience with combined strategies.

Building a bridge to recovery: the pathophysiology of LVAD-induced reverse modeling in heart failure

Heart failure mainly caused by ischemic or dilated cardiomyopathy is a life-threatening disorder worldwide. The previous work in cardiac surgery has led to many excellent surgical techniques for treating cardiac diseases, and these procedures are now able to prolong the human lifespan. However, surgical treatment for end-stage heart failure has been under-explored, although left ventricular assist device (LVAD) implantation and heart transplantation are options to treat the condition. LVAD can provide powerful circulatory support for end-stage heart failure patients and improve the survival and quality of life after implantation compared with the existing medical counterparts. Moreover, LVADs play a crucial role in the "bridge to transplantation", "bridge to recovery" and recently have served as "destination therapy". The structural and molecular changes that improve the cardiac function after LVAD implantation are called "reverse remodeling", which means that patients who have received a LVAD can be weaned from the LVAD with restoration of their cardiac function. This strategy is a desirable alternative to heart transplantation in terms of both the patient quality of life and due to the organ shortage. The mechanism of this bridge to recovery is interesting, and is different from other treatments for heart failure. Bridge to recovery therapy is one of the options in regenerative therapy which only a surgeon can provide. In this review, we pathophysiologically analyze the reverse remodeling phenomenon induced by LVAD and comment about the clinical evidence with regard to its impact on the bridge to recovery.

The war against heart failure: the Lancet lecture

Heart failure is a global problem with an estimated prevalence of 38 million patients worldwide, a number that is increasing with the ageing of the population. It is the most common diagnosis in patients aged 65 years or older admitted to hospital and in high-income nations. Despite some progress, the prognosis of heart failure is worse than that of most cancers. Because of the seriousness of the condition, a declaration of war on five fronts has been proposed for heart failure. Efforts are underway to treat heart failure by enhancing myofilament sensitivity to Ca(2+); transfer of the gene for SERCA2a, the protein that pumps calcium into the sarcoplasmic reticulum of the cardiomyocyte, seems promising in a phase 2 trial. Several other abnormal calcium-handling proteins in the failing heart are candidates for gene therapy; many short, non-coding RNAs--ie, microRNAs (miRNAs)--block gene expression and protein translation. These molecules are crucial to calcium cycling and ventricular hypertrophy. The actions of miRNAs can be blocked by a new class of drugs, antagomirs, some of which have been shown to improve cardiac function in animal models of heart failure; cell therapy, with autologous bone marrow derived mononuclear cells, or autogenous mesenchymal cells, which can be administered as cryopreserved off the shelf products, seem to be promising in both preclinical and early clinical heart failure trials; and long-term ventricular assistance devices are now used increasingly as a destination therapy in patients with advanced heart failure. In selected patients, left ventricular assistance can lead to myocardial recovery and explantation of the device. The approaches to the treatment of heart failure described, when used alone or in combination, could become important weapons in the war against heart failure.

Bridge to removal: a paradigm shift for left ventricular assist device therapy

Ventricular assist devices have become standard therapy for patients with advanced heart failure either as a bridge to transplantation or destination therapy. Despite the functional and biologic evidence of reverse cardiac remodeling, few patients actually proceed to myocardial recovery, and even fewer to the point of having their device explanted. An enhanced understanding of the biology and care of the mechanically supported patient has redirected focus on the possibility of using ventricular assist devices as a bridge to myocardial recovery and removal. Herein, we review the current issues and approaches to transforming myocardial recovery to a practical reality.

VAD as bridge to recovery in anthracycline-induced cardiomyopathy and HHV6 myocarditis

This report describes an 8-year-old child with acute anthracycline-induced cardiomyopathy triggered by human herpesvirus 6 and the subsequent implantation of an intracorporeal continuous-flow left ventricular assist device (LVAD) and the process to discharge the child from the hospital. After barely 3 months on mechanical support, the device was explanted after thorough examination. Experiences regarding LVAD removal are limited, and no guidelines for echocardiographic and hemodynamic criteria for LVAD removal in children have been published thus far. We present our institutional algorithm for device selection, surveillance in an ambulatory setting, and testing for myocardial recovery, as well as our criteria for LVAD explantation in children.

Heart failure in remission for more than 13 years after removal of a left ventricular assist device

Mechanical cardiac unloading with use of a left ventricular assist device (LVAD) is associated with substantial improvements in left ventricular function and enables subsequent LVAD explantation in some patients. We describe the case of a 35-year-old man with dilated nonischemic cardiomyopathy who was supported with an LVAD for 9 months. After the device was removed, he led a normal life for 13 years and 4 months. However, at 49 years of age, he presented with new signs and symptoms of heart failure, necessitating implantation of a 2nd LVAD. Afterwards, he has remained asymptomatic. This case is unique in that the patient lived a normal life for longer than a decade before renewed left ventricular decompensation necessitated repeat LVAD therapy. Histologic examination revealed few changes between the first device's removal in 1999 and the 2nd device's implantation in 2012.

Mesenchymal precursor cells as adjunctive therapy in recipients of contemporary left ventricular assist devices

BACKGROUND

Allogeneic mesenchymal precursor cells (MPCs) injected during left ventricular assist device (LVAD) implantation may contribute to myocardial recovery. This trial explores the safety and efficacy of this strategy.

METHODS AND RESULTS

In this multicenter, double-blind, sham-procedure controlled trial, 30 patients were randomized (2:1) to intramyocardial injection of 25 million MPCs or medium during LVAD implantation. The primary safety end point was incidence of infectious myocarditis, myocardial rupture, neoplasm, hypersensitivity reaction, and immune sensitization (90 days after randomization). Key efficacy end points were functional status and ventricular function while temporarily weaned from LVAD support (90 days after randomization). Patients were followed up until transplant or 12 months after randomization, whichever came first. Mean age was 57.4 (±13.6) years, mean left ventricular ejection fraction was 18.1%, and 66.7% were destination therapy LVADs. No safety events were observed. Successful temporary LVAD weaning was achieved in 50% of MPC and 20% of control patients at 90 days (P=0.24); the posterior probability that MPCs increased the likelihood of successful weaning was 93%. At 90 days, 3 deaths (30%) occurred in control patients, and none occurred in MPC patients. Mean left ventricular ejection fraction after successful wean was 24.0% (MPC=10) and 22.5% (control=2; P=0.56). At 12 months, 30% of MPC patients and 40% of control patients were successfully temporarily weaned from LVAD support (P=0.69), and 6 deaths (30%) occurred in MPC patients. Donor-specific HLA sensitization developed in 2 MPC and 3 control patients and resolved by 12 months.

CONCLUSIONS

In this preliminary trial, administration of MPCs appeared to be safe, and there was a potential signal of efficacy. Future studies will evaluate the potential for higher or additional doses to enhance the ability to wean LVAD recipients off support.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01442129.