Mechanical Circulatory Support Technology Research Articles

Mechanical circulatory support devices in adults with congenital heart disease.

Mechanical circulatory support is used frequently as a method of stabilizing patients with end stage heart failure who are unable to safely await allograft availability. While this technology has been fundamentally important in supporting patients with normal cardiac anatomy, it is still used infrequently in adult patients with congenital heart disease and end-stage heart failure. Here, we review the data on mechanical circulatory support technology in this small but growing population of patients with chronic heart disease prone to the development of circulatory failure. Mechanical circulatory support (MCS) has been increasingly employed in adults with congenital heart disease (ACHD) as a bridge to transplant. The new United Network for Organ Sharing listing system favoring temporary MCS use with a higher listing status offers another tool to stabilize ACHD patients and potentially shorten wait times. Both temporary and Durable MCS could help improve transplant candidacy and posttransplant outcomes in select groups of ACHD patients. Durable and temporary MCS have the potential to significantly improve access to transplant and overall transplant outcomes in ACHD patients.

Unveiling the future of cardiac care: advances in mechanical circulatory support

Congestive heart failure (CHF) is a multifaceted clinical syndrome characterized by the inability of the heart to pump blood effectively, leading to inadequate oxygen and nutrient delivery to the body tissues. Despite advancements in treatment strategies, including guideline-directed medical treatment (GDMT), end-stage CHF remains a significant cause of morbidity and mortality worldwide. Heart transplantation is considered to be the gold standard treatment of end stage CHF but constrained by the lack of organ donors, lengthening waitlists, and the negative side effects of lifelong immunosuppressive medications. Mechanical circulatory support (MCS) has emerged as a pivotal intervention for patients with end-stage CHF, serving as a bridge to recovery, transplantation, or destination therapy. The aim of this narrative review is to highlight the historical development of MCS, to assess the recent status of MCS device technology and discuss current challenges associated with complications of MCS that need to be solved in the future by device development. The history of MCS dates back to pioneering efforts in the 1960s, with significant progress in device development and utilization over decades. MCS devices, including left ventricular assist devices (LVADs), extracorporeal membrane oxygenation (ECMO), and artificial hearts, play a crucial role in providing circulatory support to patients with end-stage CHF. Recent advancements in MCS technology aim to decrease the device size, enhance blood compatibility, reduce thrombo-embolic complications, and prolong device durability and battery life and improve physiological performance of MCS. Continued research and innovation are essential to address these challenges and improve outcomes in patients with end-stage CHF. Artificial intelligence (AI) has emerged as a valuable tool in cardiovascular medicine to facilitate risk prediction, patient selection, and treatment optimization for MCS and heart transplantation. Despite these advancements, challenges persist in MCS device selection, resource allocation, and integration of AI into clinical practice. Continued research and innovation are essential to address these challenges and improve outcomes in patients with advanced heart failure.

Stroke and Mechanical Circulatory Support in Adults.

Short-term and durable mechanical circulatory support (MCS) devices represent life-saving interventions for patients with cardiogenic shock and end-stage heart failure. This review will cover the epidemiology, risk factors, and treatment of stroke in this patient population. Short-term devices such as intra-aortic balloon pump, Impella, TandemHeart, and Venoatrial Extracorporal Membrane Oxygenation, as well as durable continuous-flow left ventricular assist devices (LVADs), improve cardiac output and blood flow to the vital organs. However, MCS use is associated with high rates of complications, including ischemic and hemorrhagic strokes which carry a high risk for death and disability. Improvements in MCS technology have reduced but not eliminated the risk of stroke. Mitigation strategies focus on careful management of anti-thrombotic therapies. While data on therapeutic options for stroke are limited, several case series reported favorable outcomes with thrombectomy for ischemic stroke patients with large vessel occlusions, as well as with reversal of anticoagulation for those with hemorrhagic stroke. Stroke in patients treated with MCS is associated with high morbidity and mortality. Preventive strategies are targeted based on the specific form of MCS. Improvements in the design of the newest generation device have reduced the risk of ischemic stroke, though hemorrhagic stroke remains a serious complication.

Our Single Center Experiences with Left Ventricular Assist Device Exchange

Mechanical circulatory support technology continues to evolve to satisfy the needs of advanced heart failure patients. Despite improvements, various problems occur frequently, and surgical exchange of the pump can be a feasible treatment option. Optimal patient selection is key to success in exchange operations. Using a retrospective observational cohort design, this study aims to evaluate preoperative profiles and clinical courses of patients' undergoing a device exchange operation and identified possible contributors to in-hospital mortality. Currently, 155 left ventricular assist device (LVAD) patients are being followed up in our program. In total, 15 of 155 patients underwent a pump exchange operation. Baseline characteristics, clinical features, and laboratory results were evaluated. The primary outcome was all-cause in-hospital mortality. Of the 15 patients who underwent a pump exchange operation, thrombosis was the primary cause in 12. Five patients experienced in-hospital mortality within 30 days of LVAD exchange. The international normalized ratio (INR) was higher in patients who experienced in-hospital mortality (2.4 [±0.6] vs 1.2 [±0.4], P=.005) than in patients who survived to discharge. In addition, preoperative lactate levels were significantly higher in patients who died within 30 days (2.9 [±2.6] vs 0.9 [±0.4], P=.019). Higher INR and lactate levels could possibly contribute to in-hospital mortality, which underlines the importance of right ventricular function in this patient population. Careful evaluation of the right heart function is of great importance before exchange operations, and preoperative hemodynamic stability is crucial for better postoperative outcomes.

Temporary mechanical circulatory support devices: practical considerations for all stakeholders.

Originally intended for life-saving salvage therapy, the use of temporary mechanical circulatory support (MCS) devices has become increasingly widespread in a variety of clinical settings in the contemporary era. Their use as a short-term, prophylactic support vehicle has expanded to include procedures in the catheterization laboratory, electrophysiology suite, operating room and intensive care unit. Accordingly, MCS device design and technology continue to develop at a rapid pace. In this Review, we describe the functionality, indications, management and complications associated with temporary MCS, together with scenario-specific utilization, goal-directed development and bioengineering of future devices. We address various considerations for the use of temporary MCS devices in both prophylactic and rescue scenarios, with input from stakeholders from various cardiovascularspecialties, including interventional and heart failure cardiology, electrophysiology, cardiothoracic anaesthesiology, critical care and cardiac surgery.

Early experience with the Impella pump: Single-center registry.

With the rapid development of mechanical circulatory support technologies, patients presenting with cardiogenic shock have gained access to various treatment opportunities which were not until recently available. The Impella® pump (Abiomed, Danvers, USA) is a minimally invasive device which provides excellent left ventricular unloading and full circulatory support. The aim of the study was to review our center's experience with Impella® and to analyze the major adverse events associated with the device. From January 2020 to January 2022, a total of 32 patients underwent Impella® implantation at our center for various indications. The mean age at surgery was 60.3 ± 12.4 years and 9.4% were female. All patients presented with acute cardiogenic shock in INTERMACS Class I (53.1%) and INTERMACS Class II (46.9%). Twenty-six patients (81.25%) out of the whole cohort have been mobilized on Impella® support. Seventeen patients (53.1%) have been weaned from the Impella® support and 10 patients (31.3%) have been bridged to durable LVAD. The median time on Impella® was 7 days (IQR 5.0-11.0). 30-day mortality was 37.5%, with 56.25% survival until hospital discharge. Only one patient developed vascular complications consisting of arm hypoperfusion. There were no cases of stroke on Impella® support. The Impella® axial-flow pump seems an appropriate therapeutic option for patients with acute cardiogenic shock requiring partial or full hemodynamic support. It also provides sufficient left ventricular unloading to allow full mobilization and neurological assessment of the patients. Furthermore, Impella® offers a high rate of myocardial recovery.

Outcomes Of IABP Vs Impella As A Bridge To Cardiac Transplantation - Analysis Of National United Network For Organ Sharing Database

<h3>Introduction</h3> Temporary mechanical circulatory support technology has advanced vastly in the last decade. United Network for Organ Sharing (UNOS) heart transplant allocation system was updated in 2018 to accommodate the new Era. Among patients requiring temporary mechanical circulatory support as a bridge to transplantation, device choice relies on patient, practitioner, and institutional factors. To date, there is limited outcome data to contrast the different mechanical circulatory support platforms. <h3>Objective</h3> We aim to compare heart transplant survival in those bridged with intra-aortic balloon pump (IABP) vs Impella mechanical support. <h3>Methods</h3> Using the national UNOS database, we studied heart transplantation recipients listed on the new UNOS allocation system (oct 18^th 2018) and then compared survival of those bridged with IABP vs Impella to transplantation as status 2. The last date of follow up was Sep 4^th 2020. Cohort demographics, serum biochemistry, hemodynamic measurements, and organ support interventions were collected. Wilcoxon-Mann-Whitney test was used for continuous variables, Chi-square test for categorical variables, and Log-rank test for survival analysis. <h3>Results</h3> A total of 1721 patients (1524 IABP, 197 Impella) met our criteria, in whom, there was no difference between IABP vs Impella groups in age, BMI, or waiting list time (Table 1). We found that Impella was used more often in males (74% vs 88%, p <0.01) and Hispanics (9% vs 15% p <0.01). Clinical data are summarized in Table 1. Impella was associated with more mechanical ventilation (4 vs 16%, p <0.01), dialysis (3 vs 10%, p <0.01), and vasoactive medication support (79 vs 89%). Plasma free hemoglobin > 50 mg/dL was noted in 13.3% of the Impella group. Median survival (figure 1) was similar between IABP vs Impella (181 vs 183 days, p=0.92). <h3>Conclusion</h3> There was no observed difference in waiting time nor post-transplant survival between IABP vs Impella groups, however, the latter group was in more critical condition, and from that perspective, Impella seems to be an effective platform to bridge higher acuity status 2 patients.

Current Landscape of Temporary Percutaneous Mechanical Circulatory Support Technology

Mechanical circulatory support devices provide hemodynamic support to patients who present with cardiogenic shock. These devices work using different mechanisms to provide univentricular or biventricular support. There is a growing body of evidence supporting use of these devices as a goal for cardiac recovery or as a bridge to definitive therapy, but definitive, well-powered studies are still needed. Mechanical circulatory support devices are increasingly used using shock team and protocols, which can help clinicians in decision making, balancing operator and institutional experience and expertise. The aim of this article is to review commercially available mechanical circulatory support devices, their profiles and mechanisms of action, and the evidence available regarding their use.

Development of Inspired Therapeutics Pediatric VAD: Benchtop Evaluation of Impeller Performance and Torques for MagLev Motor Design.

Despite the availability of first-generation extracorporeal mechanical circulatory support (MCS) systems that are widely used throughout the world, there is a need for the next generation of smaller, more portable devices (designed without cables and a minimal number of connectors) that can be used in all in-hospital and transport settings to support patients in heart failure. Moreover, a system that can be universally used for all indications for use including cardiopulmonary bypass (CPB), uni- or biventricular support (VAD), extracorporeal membrane oxygenation (ECMO) and respiratory assist that is suitable for use for adult, neonate, and pediatric patients is desirable. Providing a single, well designed, universal technology could reduce the incidence of human errors by limiting the need for training of hospital staff on a single system for a variety of indications throughout the hospital rather than having to train on multiple complex systems. The objective of this manuscript is to describe preliminary research to develop the first prototype pump for use as a ventricular assist device for pediatric patients with the Inspired Universal MCS technology. The Inspired VAD Universal System is an innovative extracorporeal blood pumping system utilizing novel MagLev technology in a single portable integrated motor/controller unit which can power a variety of different disposable pump modules intended for neonate, pediatric, and adult ventricular and respiratory assistance. A prototype of the Inspired Pediatric VAD was constructed to determine the hemodynamic requirements for pediatric applications. The magnitude/range of hydraulic torque of the internal impeller was quantified. The hydrodynamic performance of the prototype pump was benchmarked using a static mock flow loop model containing a heated blood analogue solution to test the pump over a range of rotational speeds (500-6000 RPM), flow rates (0-3.5L/min), and pressures (0 to ~420 mmHg). The device was initially powered by a shaft-driven DC motor in lieu of a full MagLev design, which was also used to calculate the fluid torque acting on the impeller. The pediatric VAD produced flows as high as 4.27L/min against a pressure of 127 mmHg at 6000 RPM and the generated pressure and flow values fell within the desired design specifications. The empirically determined performance and torque values establish the requirements for the magnetically levitated motor design to be used in the Inspired Universal MagLev System. This next step in our research and development is to fabricate a fully integrated and functional magnetically levitated pump, motor and controller system that meets the product requirement specifications and achieves a state of readiness for acute ovine animal studies to verify safety and performance of the system.

Endocrine Challenges in Patients with Continuous-Flow Left Ventricular Assist Devices

Heart failure (HF) remains a leading cause of morbidity, hospitalization, and mortality worldwide. Advancement of mechanical circulatory support technology has led to the use of continuous-flow left ventricular assist devices (LVADs), reducing hospitalizations, and improving quality of life and outcomes in advanced HF. Recent studies have highlighted how metabolic and endocrine dysfunction may be a consequence of, or associated with, HF, and may represent a novel (still neglected) therapeutic target in the treatment of HF. On the other hand, it is not clear whether LVAD support, may impact the outcome by also improving organ perfusion as well as improving the neuro-hormonal state of the patients, reducing the endocrine dysfunction. Moreover, endocrine function is likely a major determinant of human homeostasis, and is a key issue in the recovery from critical illness. Care of the endocrine function may contribute to improving cardiac contractility, immune function, as well as infection control, and rehabilitation during and after a LVAD placement. In this review, data on endocrine challenges in patients carrying an LVAD are gathered to highlight pathophysiological states relevant to this setting of patients, and to summarize the current therapeutic suggestions in the treatment of thyroid dysfunction, and vitamin D, erythropoietin and testosterone administration.

Alternatives to heparin anticoagulation for cardiopulmonary bypass and extracorporeal membrane oxygenation

Cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) are both mechanical circulatory support technologies that augment the native heart and/or lung function. They involve drainage and reinfusion of blood while performing extracorporeal gas exchange. 1 In both devices, contact between patient blood and the non-endothelialized surface of the circuit triggers an inflammatory response and pro-coagulation cascade. 2–5 As a result, prophylactic anticoagulation is integral to prevent catastrophic thrombosis of the circuitry. In rare instances, there exist contraindications to heparin use, necessitating alternative management strategies. 6 In this review, we will examine heparin contraindications in mechanical circulatory support and summarize alternative approaches to anticoagulation in these circumstances.

Venoarterial Extracorporeal Membrane Oxygenation.

Venoarterial Extracorporeal Membrane Oxygenation.

Kidney replacement therapy in pediatric patients on mechanical circulatory support: challenges for the pediatric nephrologist.

The use of mechanical circulatory support (MCS) therapies in children with medically refractory cardiac failure has increased over the past two decades. With the growing experience and expertise, MCS is currently offered as a bridge to recovery or heart transplantation and in some cases even as destination therapy. Acute kidney injury (AKI) is common in patients with end-stage heart failure (ESHF). When severe AKI develops requiring kidney replacement therapy (KRT), these patients present unique challenges for the pediatric nephrology team. The use of KRT has not been adequately described in children with ESHF on the newer MCS. We also present original case series data from our center experience. The purpose of this review is to familiarize the reader with the current MCS technologies, approach to their selection, how they interact when combined with current KRT circuits, and distinguish similarities and differences. We will attempt to highlight the distinctive features of each technology, specifically focusing on growing trends in use of continuous-flow ventricular assist devices (CF-VAD) as it poses additional challenges to the pediatric nephrologist.

Hurdles to Cardioprotection in the Critically Ill.

Cardiovascular disease is the largest contributor to worldwide mortality, and the deleterious impact of heart failure (HF) is projected to grow exponentially in the future. As heart transplantation (HTx) is the only effective treatment for end-stage HF, development of mechanical circulatory support (MCS) technology has unveiled additional therapeutic options for refractory cardiac disease. Unfortunately, despite both MCS and HTx being quintessential treatments for significant cardiac impairment, associated morbidity and mortality remain high. MCS technology continues to evolve, but is associated with numerous disturbances to cardiac function (e.g., oxidative damage, arrhythmias). Following MCS intervention, HTx is frequently the destination option for survival of critically ill cardiac patients. While effective, donor hearts are scarce, thus limiting HTx to few qualifying patients, and HTx remains correlated with substantial post-HTx complications. While MCS and HTx are vital to survival of critically ill cardiac patients, cardioprotective strategies to improve outcomes from these treatments are highly desirable. Accordingly, this review summarizes the current status of MCS and HTx in the clinic, and the associated cardiac complications inherent to these treatments. Furthermore, we detail current research being undertaken to improve cardiac outcomes following MCS/HTx, and important considerations for reducing the significant morbidity and mortality associated with these necessary treatment strategies.

New versatile dual-support pediatric heart pump.

Mechanical circulatory support (MCS) devices for pediatric patients continue to lag in development behind those for adults. There is no heart pump with the design innovation to support dysfunctional states of heart failure and the anatomic heterogeneity of cardiac defects in pediatric patients. To address this unmet need, we are developing a versatile MCS technology with 2 separate blood pumps under 1 housing, whereby a centrifugal pump rotates around an axial pump. In this study, we advanced the design with a new inducer for the axial pump component and flat inlet volute for the centrifugal pump component. We conducted computational modeling of the design iterations, built prototypes, and tested their performance. The axial pump component was able to generate pressure rises of 1-112 mm Hg for 2-5 L/min at 10000-14000 RPM, and the centrifugal pump component produced pressure rises of 1-184 mm Hg for 2-5 L/min at 1750-3000 RPM. Shear stresses and blood damage estimations were less than 490 Pa and 0.5%, respectively. Axial and radial forces were also estimated to be less than 5 N for the axially and radially centered impellers. Data sets were repeatable, and data trends followed theoretical expectations. The new designs for the axial and centrifugal pumps enabled us to reduce the height of the pump while maintaining performance expectations. These findings support the continued development of this new medical device for pediatric patients.

The New Heart Failure Association Definition of Advanced Heart Failure.

The clinical course of heart failure is characterised by progressive worsening of cardiac function and symptoms. Patients progress to a condition where traditional treatment is no longer effective and advanced therapies, such as mechanical circulatory support, heart transplantation and/or palliative care, are needed. This condition is called advanced chronic heart failure. The Heart Failure Association first defined it in 2007 and this definition was updated in 2018. The updated version emphasises the role of comorbidities, including tachyarrhythmias, and the role of heart failure with preserved ejection fraction. Improvements in mechanical circulatory support technology and better disease management programmes are major advances and are radically changing the management of these patients.

Extracorporeal membrane oxygenation (ECMO) for heart failure in children: a review of current practice

Abstract Mechanical circulatory support (MCS) is a valuable treatment modality for a small proportion of children with heart failure who are refractory to conventional medical management. Advances in MCS technology, particularly in recent times with the advent of ventricular assist devices (VADs) has made it possible to offer life support for this diverse population. ECMO has historically been used to provide temporary support for children with heart failure either as a bridge to recovery and occasionally as a bridge to heart transplantation, particularly in the pre-VAD era. In contemporary practice, ECMO may be used in refractory end-stage heart failure with end-organ dysfunction as a bridge to decision regarding transplant candidacy or as a bridge to a durable MCS device pending recovery of other end-organ dysfunction. The management of a child supported on ECMO is complex and requires multidisciplinary expertise. Ensuring optimal conditions for myocardial rest and recovery whilst mitigating for complications remains challenging. Cumulative experience has shown that although survival has improved there are a growing number of ECMO survivors in need of long-term follow-up. In this review, we will focus on children with systolic heart failure requiring ECMO as a form of MCS given the established role of VADs in paediatric heart failure.

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).

Mechanical Circulatory Support Devices for Pediatric Patients With Congenital Heart Disease.

The use of mechanical circulatory support (MCS) devices is a viable therapeutic treatment option for patients with congestive heart failure. Ventricular assist devices, cavopulmonary assist devices, and total artificial heart pumps continue to gain acceptance as viable treatment strategies for both adults and pediatric patients as bridge-to-transplant, bridge-to-recovery, and longer-term circulatory support alternatives. We present a review of the current and future MCS devices for patients having congenital heart disease (CHD) with biventricular or univentricular circulations. Several devices that are specifically designed for patients with complex CHD are in the development pipeline undergoing rigorous animal testing as readiness experiments in preparation for future clinical trials. These advances in the development of new blood pumps for patients with CHD will address a significant unmet clinical need, as well as generally improve innovation of the current state of the art in MCS technology.

Novel minimally invasive surgical approach using an external ventricular assist device and extracorporeal membrane oxygenation in refractory cardiogenic shock.

The use of short-term mechanical circulatory support (MCS) has increased in the treatment of refractory cardiogenic shock (RCS). Percutaneous short-term MCS technology has emerged rapidly; however, limitations in flow and durability remain. We therefore investigated a minimally invasive surgical approach using an external ventricular assist device (VAD) and extracorporeal membrane oxygenation (ECMO) in patients with RCS. Twenty-five patients underwent minimally invasive external VAD insertion with a magnetically levitated centrifugal pump for various causes of cardiogenic shock between April 2010 and May 2016. An external VAD was established with left ventricular apical cannulation through a minithoracotomy and right or left axillary artery cannulation. In patients with biventricular failure or pulmonary complications, femoral venous cannulation was added as an additional inflow source, and ECMO was spliced into the external VAD circuit. Mean patient age was 58 ± 9.1 and 80% were men. All patients were in Interagency Registry for Mechanically Assisted Circulatory Support profile I RCS. The aetiology of RCS was decompensated chronic heart failure in 13 (52%), and acute myocardial infarction in 12 (48%). Twenty-three (92%) received percutaneous short-term MCS prior to surgery. The procedure was performed without cardiopulmonary bypass in all patients. ECMO was added in 17 patients (68%) and explanted after a median of 4 days of support. The average flow obtained was 5.3 ± 1.1 l/min. The median duration of external VAD support was 22 days. Major complications during support included bleeding events in seven (28%) and cerebrovascular events in four (16%). The in-hospital mortality rate was 32%. Seventeen patients (68%) survived to the next destination including myocardial recovery in three (12%), device exchange to a durable VAD in 12 (48%) and heart transplantation in two (8%). The Kaplan-Meier survival rates at 6 months and 1 year were 92% and 77%, respectively. Our minimally invasive surgical approach using an external VAD is a feasible strategy for patients with cardiogenic shock who are refractory to percutaneous short-term MCS support.