Mechanical circulatory support for the right ventricle in combination with a left ventricular assist device

Mechanical Circulatory Support Devices in Patients with High-Risk Pulmonary Embolism

Pulmonary embolism (PE) is a common acute cardiovascular condition. Within this review, we discuss the incidence, pathophysiology, and treatment options for patients with high-risk and massive pulmonary embolisms. In particular, we focus on the role of mechanical circulatory support devices and their possible therapeutic benefits in patients who are unresponsive to standard therapeutic options. Moreover, attention is given to device selection criteria, weaning protocols, and complication mitigation strategies. Finally, we underscore the necessity for more comprehensive studies to corroborate the benefits and safety of MCS devices in PE management.

Multi-Method Investigation of Blood Damage Induced By Blood Pumps in Different Clinical Support Modes

To investigate the effects of blood pumps operated in different modes on nonphysiologic flow patterns, cell and protein function, and the risk of bleeding, thrombosis, and hemolysis, an extracorporeal blood pump (CentriMag) was operated in three clinical modalities including heart failure (HF), venous-venous (V-V) extracorporeal membrane oxygenation (ECMO), and venous-arterial (V-A) ECMO. Computational fluid dynamics (CFD) methods and coupled hemolysis models as well as recently developed bleeding and thrombosis models associated with changes in platelet and von Willebrand factor (vWF) function were used to predict hydraulic performance and hemocompatibility. The V-A ECMO mode had the highest flow losses and shear stress levels, the V-V ECMO mode was intermediate, and the HF mode was the lowest. Different nonphysiologic flow patterns altered cell/protein morphology and function. The V-A ECMO mode resulted in the highest levels of platelet activation, receptor shedding, vWF unfolding, and high molecular weight multimers vWF (HMWM-vWF) degradation, leading to the lowest platelet adhesion and the highest vWF binding capacity, intermediate in the V-V ECMO mode, and opposite in the HF mode. The V-A ECMO mode resulted in the highest risk of bleeding, thrombosis, and hemolysis, with the V-V ECMO mode intermediate and the HF mode lowest. These findings are supported by published experimental or clinical statistics. Further studies found that secondary blood flow passages resulted in the highest risk of blood damage. Nonphysiologic blood flow patterns were strongly associated with cell and protein function changing, blood damage, and complications.

Right ventricular dysfunction in left ventricular assist device candidates: is it time to change our prospective?

The use of left ventricular assist devices (LVAD) has significantly increased in the last years, trying to offer a therapeutic alternative to heart transplantation, in light also to the significant heart donor shortage compared to the growing advanced heart failure population. Despite technological improvements in the devices, LVAD-related mortality is still fairly high, with right heart failure being one of the predominant predictors. Therefore, many efforts have been made toward a thorough right ventricular (RV) evaluation prior to LVAD implant, considering clinical, laboratory, echocardiographic, and invasive hemodynamic parameters. However, there is high heterogeneity regarding both which predictor is the strongest as well as the relative cut-off values, and a consensus has not been reached yet, increasing the risk of facing patients in which the distinction between good or poor RV function cannot be surely reached. In parallel, due to technological development and availability of mechanical circulatory support of the RV, LVADs are being considered even in patients with suboptimal RV function. The aim of our review is to analyze the current evidence regarding the role of RV function prior to LVAD and its evaluation, pointing out the extreme variability in parameters that are currently assessed and future prospective regarding new diagnostic tools. Finally, we attempt to gather the available information on the therapeutic strategies to use in the peri-operative phase, in order to reduce the incidence of RV failure, especially in patients in which the preoperative evaluation highlighted some conflicting results with regard to ventricular function.

Biventricular assist devices and total artificial heart: Strategies and outcomes

In contrast to the advanced development of the left ventricular assist device (LVAD) therapy for advanced heart failure, the mechanical circulatory support (MCS) with biventricular assist device (BVAD) and total artificial heart (TAH) options remain challenging. The treatment strategy of BVAD and TAH therapy largely depends on the support duration. For example, an extracorporeal centrifugal pump, typically referred to as a temporary surgical extracorporeal right ventricular assist device, is implanted for the short term with acute right ventricular failure following LVAD implantation. Meanwhile, off-label use of a durable implantable LVAD is a strategy for long-term right ventricular support. Hence, this review focuses on the current treatment strategies and clinical outcomes based on each ventricle support duration. In addition, the issue of heart failure post-heart transplantation (post-HT) is explored. We will discuss MCS therapy options for post-HT recipients.

Supporting the "forgotten" ventricle: The evolution of percutaneous RVADs

Right heart failure (RHF) can occur as the result of an acute or chronic disease process and is a challenging clinical condition for surgeons and interventionalists to treat. RHF occurs in approximately 0.1% of patients after cardiac surgery, in 2-3% of patients following heart transplantation, and in up to 42% of patients after LVAD implantation. Regardless of the cause, RHF portends high morbidity and mortality and is associated with longer hospital stays and higher healthcare costs. The mainstays of traditional therapy for severe RHF have included pharmacological support, such as inotropes and vasopressors, and surgical right ventricular (RV) assist devices. However, in recent years catheter-based mechanical circulatory support (MCS) strategies have offered novel solutions for addressing RHF without the morbidity of open surgery. This manuscript will review the pathophysiology of RHF, including the molecular underpinnings, gross structural mechanisms, and hemodynamic consequences. The evolution of techniques for supporting the right ventricle will be explored, with a focus on various institutional experiences with percutaneous ventricular assist devices.

Mechanical circulatory support devices and treatment strategies for right heart failure

The importance of right heart failure (RHF) treatment is magnified over the years due to the increased risk of mortality. Additionally, the multifactorial origin and pathophysiological mechanisms of RHF render this clinical condition and the choices for appropriate therapeutic target strategies remain to be complex. The recent change in the United Network for Organ Sharing (UNOS) allocation criteria of heart transplant may have impacted for the number of left ventricular assist devices (LVADs), but LVADs still have been widely used to treat advanced heart failure, and 4.1 to 7.4% of LVAD patients require a right ventricular assist device (RVAD). In addition, patients admitted with primary left ventricular failure often need right ventricular support. Thus, there is unmet need for temporary or long-term support RVAD implantation exists. In RHF treatment with mechanical circulatory support (MCS) devices, the timing of the intervention and prediction of duration of the support play a major role in successful treatment and outcomes. In this review, we attempt to describe the prevalence and pathophysiological mechanisms of RHF origin, and provide an overview of existing treatment options, strategy and device choices for MCS treatment for RHF.

Right Ventricular Function in Chronic Heart Failure: From the Diagnosis to the Therapeutic Approach

There is growing attention for the study of the right ventricle in cardiovascular disease and in particular in heart failure. In this clinical setting, right ventricle dysfunction is a significant marker of poor prognosis, regardless of the degree of left ventricular dysfunction. Novel echocardiographic methods allow for obtaining a more complete evaluation of the right ventricle anatomy and function as well as of the related abnormalities in filling pressures. Specific and effective therapies for the right ventricle dysfunction are still not well defined and this represents the most difficult and important challenge. This article focuses on available diagnostic techniques for studying right ventricle dysfunction as well as on the therapies for right ventricle dysfunction.