Development Of Mechanical Circulatory Support Research Articles

Longitudinal cardiac dimensions in patients undergoing LVAD implantation.

In conventional left ventricular assist devices (LVAD), a separate outflow graft is sutured to the ascending aorta. Novel device designs may include a transventricular outflow cannula crossing the aortic valve (AV). While transversal ventricular dimensions are well investigated in patients with severe heart failure, little is known about the longitudinal dimensions. These dimensions are, however, particularly critical for the design and development of mechanical circulatory support (MCS) devices with transaortic outflow cannula. In an explorative retrospective cohort study at the University Medical Center Freiburg, Germany, the longitudinal cardiac dimensions of patients undergoing computed tomography angiography (CTA) before and, if available, after LVAD implantation were analyzed. Among others, the following dimensions were assessed: (a) apex to AV, (b) apex to mitral valve, (c) AV to sinotubular junction (STJ), (d) apex to STJ, (e) apex to brachiocephalic artery (BCA), and (f) AV to BCA. In total, 44 LVAD patients (36 male, age 55.8 years, height 1.75 m) were included. The longitudinal cardiac dimensions were (a) 114.5 ± 12.1 mm, (b) 108.0 ± 12.4 mm, (c) 20.9 ± 2.9, (d) 135.4 ± 13.4 mm, (e) 206.0 ± 18.3, and (f) 91.5 ± 9.8 mm. Postoperatively, (a) and (b) decreased by 31.5% and 39.5%, respectively (N = 14). Longitudinal cardiac dimensions may be reduced by up to 40% after LVAD implantation. A better knowledge of these dimensions and their postoperative alterations in LVAD patients may improve surgical planning and help to design MCS devices with transventricular outflow cannula.

Clinical Application of Extracorporeal Membrane Oxygenation in the Treatment of Fulminant Myocarditis.

Fulminant myocarditis (FM) is a rare but serious clinical syndrome which can be characterized by the rapid deterioration of cardiac function, with cardiogenic shock (CS) and arrhythmic electrical storms being common presentations, often requiring adjunctive support with mechanical circulatory devices. With the development of mechanical circulatory support (MCS) devices, there are now more and more studies investigating the application of MCS in FM patients, and the use of extracorporeal membrane oxygenation (ECMO) to treat FM has shown good survival rates. This review elucidates the treatment of FM, and the application and clinical outcomes associated with ECMO intervention.

Perspectives and Considerations of IABP in the Era of ECMO for Cardiogenic Shock.

The development of mechanical circulatory support (MCS) has been rapid, and its use worldwide in patients with cardiogenic shock is increasingly widespread. However, current statistical data and clinical research do not demonstrate its significant improvement in the patient prognosis. This review focuses on the widely used intra-aortic balloon pumps (IABP) and veno-arterial extracorporeal membrane oxygenation (VA-ECMO), analyzing and comparing their characteristics, efficacy, risk of complications, and the current exploration status of left ventricular mechanical unloading. Subsequently, we propose a rational approach to viewing the negative outcomes of current MCS, and look ahead to the future development trends of IABP.

Cardiogenic shock code 2023. Expert document for a multidisciplinary organization that allows quality care

Despite the efforts made to improve the care of cardiogenic shock (CS) patients, including the development of mechanical circulatory support (MCS), the prognosis of these patients continues to be poor. In this context, CS code initiatives arise, based on providing adequate, rapid, and quality care to these patients. In this multidisciplinary document we try to justify the need to implement the SC code, defining its structure/organization, activation criteria, patient flow according to care level, and quality indicators. Our specific purposes are: a) to present the peculiarities of this condition and the lessons of infarction code and previous experiences in CS; b) to detail the structure of the teams, their logistics and the bases for the management of these patients, the choice of the type of MCS, and the moment of its implantation, and c) to address challenges to SC code implementation, including the uniqueness of the pediatric SC code. There is an urgent need to develop protocolized, multidisciplinary, and centralized care in hospitals with a large volume and experience that will minimize inequity in access to the MCS and improve the survival of these patients. Only institutional and structural support from the different administrations will allow optimizing care for CS.

Código shock cardiogénico 2023. Documento de expertos para una organización multidisciplinaria que permita una atención de calidad

Despite the efforts made to improve the care of cardiogenic shock (CS) patients, including the development of mechanical circulatory support (MCS), the prognosis of these patients continues to be poor. In this context, CS code initiatives arise, based on providing adequate, rapid, and quality care to these patients. In this multidisciplinary document we try to justify the need to implement the SC code, defining its structure/organization, activation criteria, patient flow according to care level, and quality indicators. Our specific purposes are: a) to present the peculiarities of this condition and the lessons of infarction code and previous experiences in CS; b) to detail the structure of the teams, their logistics and the bases for the management of these patients, the choice of the type of MCS, and the moment of its implantation, and c) to address challenges to SC code implementation, including the uniqueness of the pediatric SC code. There is an urgent need to develop protocolized, multidisciplinary, and centralized care in hospitals with a large volume and experience that will minimize inequity in access to the MCS and improve the survival of these patients. Only institutional and structural support from the different administrations will allow optimizing care for CS.

Additive Manufacturing for VADs and TAHs - a Review

Heart disease or Advanced/Congestive Heart Failure (CHF) is one of the serious causes of death. Due to availability of low volumes of donor hearts, there has been an ongoing development of Mechanical Circulatory Support (MCS): Ventricular Assist Devices (VADs) and total heart replacement by Total Artificial Hearts (TAHs) for over 60 years. MCS systems had seen three phases of advancement. The first generation were largely mechanical devices and had pulsatility in their action, but were highly cumbersome, unreliable due to fatigue cracks and required an external pneumatic power and control. Smaller and continuous flow devices are the second generation MCS devices. Because of compact sizing they were suitable for implantations and were more durable than the first generation devices. Problems like pump thrombosis drove the development of motors with levitating or hydrodynamic rotors, leading to the development of third generation devices. Manufacturing of these electromagnetic devices for implantation has to adhere to the constraints of compatibility, space and weight. With the advent of new biomaterials, additive manufacturing is reportedly playing a significant role. Additive manufacturing reported for electromagnetic and electronic components had yielded considerably good performance. This paper reviews materials in electrical and electronics and also in bio medical sector suitable for Additive Manufacturing. An attempt is made to identify the materials that may be suitable for VADs and TAHs and the challenges to use AM techniques that complement each other to create next generation integrated-VADs and integrated-TAHs.

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.

Poscadiotomy Cardiogenic Shock: Characteristics, Management and Prognostic in a Contemporary Cohort

Post-cardiotomy cardiogenic shock (PCCS) continues to present a high mortality despite the increasing development of mechanical circulatory support (MCS). Our aim was to describe the characteristics and prognosis of patients with this type of cardiogenic shock (CS) in a contemporary cohort.

Trasplante cardiaco y soporte circulatorio mecánico para pacientes con insuficiencia cardiaca avanzada

Patients with advanced heart failure have a poor prognosis and heart transplant is still the best treatment option. However, the scarcity of donors, long waiting times, and an increasing number of unstable patients have favored the development of mechanical circulatory support. This review summarizes the indications for heart transplant, candidate evaluation, current immunosuppression strategies, the evaluation and treatment of rejection, infectious prophylaxis, and short and long-term outcomes. Regarding mechanical circulatory support, we distinguish between short- and long-term support and the distinct strategies that can be used: bridge to decision, recovery, candidacy, transplant, and destination therapy. We then discuss indications, risk assessment, management of complications, especially with long-term support, and outcomes. Finally, we discuss future challenges and how the widespread use of long-term support for patients with advanced heart failure will only be viable if their complications and costs are reduced.Full English text available from:www.revespcardiol.org/en

Heart Transplant and Mechanical Circulatory Support in Patients With Advanced Heart Failure

Patients with advanced heart failure have a poor prognosis and heart transplant is still the best treatment option. However, the scarcity of donors, long waiting times, and an increasing number of unstable patients have favored the development of mechanical circulatory support. This review summarizes the indications for heart transplant, candidate evaluation, current immunosuppression strategies, the evaluation and treatment of rejection, infectious prophylaxis, and short and long-term outcomes. Regarding mechanical circulatory support, we distinguish between short- and long-term support and the distinct strategies that can be used: bridge to decision, recovery, candidacy, transplant, and destination therapy. We then discuss indications, risk assessment, management of complications, especially with long-term support, and outcomes. Finally, we discuss future challenges and how the widespread use of long-term support for patients with advanced heart failure will only be viable if their complications and costs are reduced.

What cardiologists should know to manage acute complications in mechanical circulatory support recipients

Patients with advanced heart failure refractory to optimal medical treatment have a high mortality and a poor quality of life with frequent hospital admissions. The lack of alternative treatment options has prompted the development of mechanical circulatory support (MCS) devices, first as bridge to heart transplant and subsequently as destination therapy as a valid alternative to transplant. Last generation MCS devices are mechanically reliable and their management has become increasingly less complex. Nowadays, medium-term survival does not significantly differ between MCS and heart transplant recipients. MCS management programs require a multidisciplinary team to optimize the pathway leading to rehabilitation and improved quality of life and decrease the frequent occurrence of complications. However, in the near future with the growing number of implants, the chances for clinical cardiologists to come across a MCS recipient will increase. The management of general or acute problems will no longer be limited to tertiary implanting centers. A key issue to improve patient outcomes is the provision of a smooth and careful transition from the hospital environment to home care. The aim of this review is to start this process by providing basic notions and general indications through several scenarios of MCS recipients presenting to the emergency room for acute clinical problems.

Development of ventricular assist devices in China: present status, opportunities and challenges

The growing number of heart failure patients and the scarcity of organ donors account for the huge need for the development of mechanical circulatory systems, including ventricular assist devices (VADs) and artificial hearts, in China. Several research programmes on blood pumps have been under way for the last three decades. However, unlike in other countries, the development of VADs has been extremely slow, and no system is currently approved and available for clinical application. There are many reasons for this situation. This article provides an overview of the present development of experimental and clinical research on VADs in China. In addition, the challenges for the clinical development of mechanical circulatory support in China are discussed.

Benefits of Aggressive Medical Management in a Bovine Model of Chronic Ischemic Heart Failure

A major limitation in the development of mechanical circulatory support (MCS) devices has been the lack of a clinically relevant, stable, and reproducible large animal chronic heart failure (HF) model. High mortality rates have been reported with large animal chronic HF models. In this study, methods of medical management to improve survival rate (SR) were investigated. Chronic ischemic HF (IHF) was induced in Jersey calves using a microembolization technique via fluoroscopy-guided injection of 90 μm microspheres into the coronary vasculature. Animals were divided into 1) Control--multiple embolization procedures with conservative therapy (n = 9); 2) treatment group 1 (TG1)--single embolization procedure with moderately aggressive therapy (n = 8); and 3) TG2--single embolization procedure with aggressive medical management (n = 20). The groups were not randomized with data analyzed retrospectively. Mean SR, body condition score, body weight, hemodynamic, echocardiography, and histopathology indices were recorded up to 60 days postembolization. SR improved from 56% (Control) to 75% (TG1) and 90% (TG2) using an aggressive medical management regimen of analgesia, diuretics, beta-blockade, antiarrhythmics, vasodilators, and inotropes. These findings support the hypothesis that a single coronary microembolization procedure and aggressive medical therapy produces a clinically relevant chronic IHF model with a significantly higher SR than conservative medical therapy.

Miniaturization of mechanical circulatory support systems.

Heart failure (HF) is increasing worldwide and represents a major burden in terms of health care resources and costs. Despite advances in medical care, prognosis with HF remains poor, especially in advanced stages. The large patient population with advanced HF and the limited number of donor organs stimulated the development of mechanical circulatory support (MCS) devices as a bridge to transplant and for destination therapy. However, MCS devices require a major operative intervention, cardiopulmonary bypass, and blood component exposure, which have been associated with significant adverse event rates, and long recovery periods. Miniaturization of MCS devices and the development of an efficient and reliable transcutaneous energy transfer system may provide the vehicle to overcome these limitations and usher in a new clinical paradigm in heart failure therapy by enabling less invasive beating heart surgical procedures for implantation, reduce cost, and improve patient outcomes and quality of life. Further, it is anticipated that future ventricular assist device technology will allow for a much wider application of the therapy in the treatment of heart failure including its use for myocardial recovery and as a platform for support for cell therapy in addition to permanent long-term support.

Destination Therapy: Does Progress Depend on Left Ventricular Assist Device Development?

The role of therapy using mechanical circulatory support devices has evolved rapidly over the last two decades. New developments in the field achieved smaller adverse events, but, currently, only minor improvements in survival were observed in published observational data. The authors discuss the development of mechanical circulatory support devices as a "destination therapy" option for patients who have end-stage heart failure and are ineligible for heart transplantation as it relates to left ventricular assist device development.

Development of mechanical circulatory support devices at the University of Tokyo

The development of mechanical circulatory support devices at the University of Tokyo has focused on developing a small total artificial heart (TAH) since achieving 532 days of survival of an animal with a paracorporial pneumatically driven TAH. The undulation pump was invented to meet this purpose. The undulation pump total artificial heart (UPTAH) is an implantable TAH that uses an undulation pump. To date, the UPTAH has been implanted in 71 goats weighting from 39 to 72 kg. The control methods are very important in animal experiments, and sucking control was developed to prevent atrial sucking. Rapid left-right balance control was performed by monitoring left atrial pressure to prevent acute lung edema caused by the rapid increase in both arterial pressure and venous return associated with the animal becoming agitated. Additionally, 1/R control was applied to stabilize the right atrial pressure. By applying these control methods, seven goats survived more than 1 month. The maximum survival period was 63 days. We are expecting to carry out longer term animal experiments with a recent model of TAH. In addition to the TAH, an undulation pump ventricular assist device (UPVAD), which is an implantable ventricular assist device (VAD), has been in development since 2002, based on the technology of the UPTAH. The UPVAD was implanted in six goats; three goats survived for more than 1 month. While further research and development is required to complete the the UPVAD system, the UPVAD has good potential to be realized as an implantable pulsatile-flow VAD.

Clinical applicability of preconditioning and postconditioning: The cardiothoracic surgeons's view☆

“Any surgeon who operates upon the heart should lose the respect of his colleagues.” Theodor Billroth The field of cardiac surgery has progressed significantly since this 19th century quote from Dr Billroth. The ability to perform cardiac procedures was limited by the inability to support the circulation and to offer adequate myocardial protection. Cardiac surgery as a profession was made possible by our ability to translate experimental research into the clinical arena. Two major concepts allowed the feasibility of open-heart surgery: 1) the development of mechanical circulatory support and 2) our understanding of myocardial protection. Myocardial protection refers to all strategies that increase the myocardium's ability to withstand an ischemic insult. Ischemic and reperfusion injuries are principally responsible for cardiac failure, morbidity and mortality following cardiac surgery. Bigelow et al.'s original work on hypothermia, driven by the desire to protect the brain from ischemic insult, led to the discovery that the myocardium also benefited from hypothermia during cardiac surgery [1]. The next development in the field of myocardial protection was the use of cardioplegia. Melrose et al. first used their solution to initiate cardiac arrest as well as to cool the heart [2,3]. Their strategy combined two methods of myocardial protection: hypothermia and cardiac standstill. Both strategies reduce myocardial oxygen demand and therefore decreased ischemic injury. The field of myocardial protection then shifted to providing oxygen to the myocardium while arrested. The use of blood was introduced as a method to increase myocardial oxygen delivery [4]. Cardiac surgeons quickly adopted blood cardioplegia as their myocardial protective strategy of choice. This strategy remains the mainstay of myocardial protection. Cardioplegia protects the myocardium by providing continuous or intermittent oxygen while simultaneously reducing cardiomyocyte oxygen demand through both hypothermia and cardiac arrest. Although an effective strategy, cardioplegia does not inherently …