Left ventricular restoration devices post myocardial infarction

Postmyocardial Infarction Ventricular Aneurysm: JACC Focus Seminar 5/5

Ventricular aneurysm represents a rare complication of transmural acute myocardial infarction, although other cardiac, congenital, or metabolic diseases may also predispose to such condition. Ventricular expansion includes all the cardiac layers, usually with a large segment involved. Adverse events include recurrent angina, reduced ventricular stroke volume with congestive heart failure, mitral regurgitation, thromboembolism, and ventricular arrhythmias. Multimodality imaging is paramount to provide comprehensive assessment, allowing for appropriate therapeutic decision-making. When indicated, surgical intervention remains the gold standard, although additional therapy (heart failure, anticoagulation, and advanced antiarrhythmic treatment) might be required. However, the STICH (Surgical Treatment for Ischemic Heart Failure) trial did not show any advantage from adding surgical ventricular reconstruction to coronary artery bypass surgery in terms of survival, rehospitalization or symptoms, compared with revascularization alone. Finally, implantable cardiac defibrillator may reduce the risk of fatal arrhythmias.

Cell Therapy in the Treatment of Coronary Heart Disease

Heart failure is a leading cause of death in patients who have suffered a myocardial infarction. Despite the timely use of modern reperfusion therapies such as thrombolysis, surgical revascularization and balloon angioplasty, they are sometimes unable to prevent the development of significant areas of myocardial damage and subsequent heart failure. Research efforts have focused on developing strategies to improve the functional status of myocardial injury areas. Consequently, the restoration of cardiac function using cell therapy is an exciting prospect. This review describes the characteristics of various cell types relevant to cellular cardiomyoplasty and presents findings from experimental and clinical studies investigating cell therapy for coronary heart disease. Cell delivery methods, optimal dosage and potential treatment mechanisms are discussed.

Update on Percutaneous Treatment for HFrEF: A Great Armamentarium for a Poor Ventricular Function

Pharmacological treatment is the cornerstone therapy of heart failure with reduced ejection fraction (HFrEF). In addition, several percutaneous techniques have been developed to treat symptomatic patients, with specific heart failure (HF) phenotypes (e.g., valvular heart disease) that require non-pharmacological treatment. Given their prognostic relevance, it is imperative to deliver high-level patient care. This review provides a clinical overview on the available data regarding transcatheter devices in the armamentarium of contemporary interventional cardiologists, focusing on the clinical and anatomical selection criteria.

Restructuring the Heart From Failure to Success: Role of Structural Interventions in the Realm of Heart Failure

Heart failure through the spectrum of reduced (HFrEF), mid-range (or mildly reduced or HFmEF), and preserved ejection fraction (HFpEF), continues to plague patients' quality of life through recurrent admissions and high mortality rates. Despite tremendous innovation in medical therapy, patients continue to experience refractory congestive symptoms due to adverse left ventricular remodeling, significant functional mitral regurgitation (FMR), and right-sided failure symptoms due to significant functional tricuspid regurgitation (FTR). As most of these patients are surgically challenging for open cardiac surgery, the past decade has seen the development and evolution of different percutaneous structural interventions targeted at improving FMR and FTR. There is renewed interest in the sphere of left ventricular restorative devices to effect reverse remodeling and thereby improve effective stroke volume and patient outcomes. For patients suffering from HFpEF, there is still a paucity of disease-modifying effective medical therapies, and these patients continue to have recurrent heart failure exacerbations due to impaired left ventricular relaxation and high filling pressures. Structural therapies involving the implantation of inter-atrial shunt devices to decrease left atrial pressure and the development of implantable devices in the pulmonary artery for real-time hemodynamic monitoring would help redefine treatment and outcomes for patients with HFpEF. Lastly, there is pre-clinical data supportive of soft robotic cardiac sleeves that serve to improve cardiac function, can assist contraction as well as relaxation of the heart, and have the potential to be customized for each patient. In this review, we focus on the role of structural interventions in heart failure as it stands in current clinical practice, evaluate the evidence amassed so far, and review promising structural therapies that may transform the future of heart failure management.

Mitral valve replacement and implantation of an extracardial mesh frame in patients with severe heart failure: results of a clinical study and a description of a clinical case 18 years after surgery

Aim    Dilated cardiomyopathy (DCMP) is a major cause for severe heart failure. Development of a combination (drug and surgery) treatment of this disease is relevant. This prospective observational study was aimed at evaluating short- and long-term results of extracardiac mesh implantation in DCMP patients with heart failure resistant to the optimum drug therapy.Material and methods    The extracardiac mesh ACOR-1 was implanted in 15 patients with DCMP. All meshes were produced individually for each patient and made of Gelweave (great Britain) vascular graft strips. The mesh size corresponded to the heart diastolic size, which was measured after achieving a maximum possible clinical improvement for the patient. Long-term results were followed for up to 4 years. Mean age of patients was 43.1±10.8 years (from 28 to 62 years). One patient was followed up for 18 years. Data of that patient were presented as a clinical case report.Results    From October, 2003 through October, 2007, 15 DCMP patients received mesh implants. Cases of in-hospital death were absent. In 3 mos. after the surgery, left ventricular volumes decreased (end-diastolic volume decreased from 251.7±80.7 to 229.0±61.3 ml; end-systolic volume decreased from 182.3±73.6 to 167.7±46.2 ml), and the left ventricular pump function improved (ejection fraction increased from 25.2±6.0 to 27.1±5.1 %; cardiac index increased from 2.0±0.5 to 2.4±0.7 ml /min /m2). The functional state of patients improved by one NYHA class, from 3.7±0.3 to 2.8±0.6. In some cases, the left ventricular size and the systolic function completely normalized. There were no episodes of circulatory decompensation in the long term after surgery. Actuarial survival for the observation period was 100%.Conclusion    Implantation of extracardiac mesh prevented progression of heart dilatation and, in combination with drug therapy, it may represent an effective method for treatment of DCMP.

Device Therapy in Chronic Heart Failure: JACC State-of-the-Art Review

The regulatory landscape for device-based heart failure (HF) therapies has seen a major shift in the last 7 years. In 2013, the U.S. Food and Drug Administration released guidance for early feasibility and first-in-human studies, thereby encouraging device innovation, and in 2016 the U.S. Congress authorized the Breakthrough Devices Program to expedite access for Americans to innovative devices indicated for diagnosis and treatment of serious illnesses, such as HF. Since December 2016, there has been an increase in the number of HF devices for which manufacturers are seeking approval through the breakthrough designation pathway. This has led to a rapid uptake in the development and evaluation of device-based HF therapies. This article reviews the current and future landscape of device therapies for chronic HF and associated comorbidities and the regulatory environment that is driving current and future innovation.

Human umbilical cord tissue-derived mesenchymal stromal cells as adjuvant therapy for myocardial infarction: a review of current evidence focusing on pre-clinical large animal models and early human trials

Although biologically appealing, the concept of tissue regeneration underlying first- and second-generation cell therapies has failed to translate into consistent results in clinical trials. Several types of cells from different origins have been tested in pre-clinical models and in patients with acute myocardial infarction (AMI). Mesenchymal stromal cells (MSCs) have gained attention because of their potential for immune modulation and ability to promote endogenous tissue repair, mainly through their secretome. MSCs can be easily obtained from several human tissues, the umbilical cord being the most abundant source, and further expanded in culture, making them attractive as an allogeneic "of-the-shelf" cell product, suitable for the AMI setting. The available evidence concerning umbilical cord-derived MSCs in AMI is reviewed, focusing on large animal pre-clinical studies and early human trials. Molecular and cellular mechanisms as well as current limitations and possible translational solutions are also discussed.

Electroacupuncture preconditioning attenuates acute myocardial ischemia injury through inhibiting NLRP3 inflammasome activation in mice

AIMS

Electro-acupuncture pretreatment (EAP) plays a protective role in myocardial ischemia (MI) injury. However, the underlying mechanism remains unclear. A growing body of evidence suggests postinfarction inflammatory response directly affects the remodeling of ventricular function. The purpose of this study was to investigate whether EAP alleviates MI through NLRP3 inflammasome inhibition.

MATERIALS AND METHODS

We constructed an AMI model by ligating the left anterior descending (LAD) coronary artery after 3 days of EAP with C57BL/6 mice. Echocardiography and TTC staining were employed to evaluate cardiac function and infarct size after 24 h of ischemia. HE staining and immunohistochemistry were employed to determine inflammatory level. Then, inflammasome activation was detected by western blotting, and macrophage polarization and neutrophil infiltration were observed by flow cytometry.

KEY FINDINGS

Our preliminary findings showed that EAP reduced the infarct area and increased fractional shortening (FS) and ejection fraction (EF) and decreased the degree of inflammation after AMI injury. Meanwhile, EAP inhibited the expression of NLRP3, cleaved caspase-1 and IL-1β in ischemia myocardial tissue, companied by inhibiting the expression of F4/80⁺, CD11b⁺, CD206^low macrophages and activated M2 macrophage, and decreasing Ly-6G⁺CD11b⁺ neutrophils in ischemia myocardial and spleen tissue.

SIGNIFICANCE

EAP inhibits the activation of NLRP3 inflammasome, promotes M2 polarization of macrophages and reduces the recruitment of neutrophils in damaged myocardium, thereby decreases the infarct size and improves the cardiac function.

ACE inhibitor suppresses cardiac remodeling after myocardial infarction by regulating dendritic cells and AT2 receptor-mediated mechanism in mice

Dendritic cells (DCs) play a complex role in the progression of myocardial infarction (MI). The impact of angiotensin-converting enzyme (ACE) inhibitor therapy, partly via affecting DCs maturation and recruitment, was tested on a MI mouse model. Furthermore, the cardioprotective effects of ACEI were enhanced through attenuating migration of DCs from the spleen into peripheral circulation, thereby inhibiting DCs maturation and tissue inflammation. ACEI repress DCs immune inflammatory response through down-regulating DCs maturation surface markers and regulating inflammatory cytokines, which led to a higher survival rate, improved function and remodeling through decreased inflammatory response after MI. However, inhibition of AT₂R activation, resulted in a reduction of ACEI effects on DCs. The potent anti-inflammatory effect of ACEI can partially be attributed to its impact on DCs through activation of AT₂R, which may provide a new target mechanism for ACEI therapy after MI.

Optimizing Epicardial Restraint and Reinforcement Following Myocardial Infarction: Moving Towards Localized, Biomimetic, and Multitherapeutic Options

The mechanical reinforcement of the ventricular wall after a myocardial infarction has been shown to modulate and attenuate negative remodeling that can lead to heart failure. Strategies include wraps, meshes, cardiac patches, or fluid-filled bladders. Here, we review the literature describing these strategies in the two broad categories of global restraint and local reinforcement. We further subdivide the global restraint category into biventricular and univentricular support. We discuss efforts to optimize devices in each of these categories, particularly in the last five years. These include adding functionality, biomimicry, and adjustability. We also discuss computational models of these strategies, and how they can be used to predict the reduction of stresses in the heart muscle wall. We discuss the range of timing of intervention that has been reported. Finally, we give a perspective on how novel fabrication technologies, imaging techniques, and computational models could potentially enhance these therapeutic strategies.

Genetic and Tissue Engineering Approaches to Modeling the Mechanics of Human Heart Failure for Drug Discovery

Heart failure is the leading cause of death in the western world and as such, there is a great need for new therapies. Heart failure has a variable presentation in patients and a complex etiology; however, it is fundamentally a condition that affects the mechanics of cardiac contraction, preventing the heart from generating sufficient cardiac output under normal operating pressures. One of the major issues hindering the development of new therapies has been difficulties in developing appropriate in vitro model systems of human heart failure that recapitulate the essential changes in cardiac mechanics seen in the disease. Recent advances in stem cell technologies, genetic engineering, and tissue engineering have the potential to revolutionize our ability to model and study heart failure in vitro. Here, we review how these technologies are being applied to develop personalized models of heart failure and discover novel therapeutics.