Newer treatments for decompensated heart failure: focus on levosimendan

GKT137831 and hydrogen peroxide increase the release of 6-nitrodopamine from the human umbilical artery, rat-isolated right atrium, and rat-isolated vas deferens

Introduction: The human umbilical artery (HUA), rat-isolated right atrium, and rat-isolated vas deferens present a basal release of 6-nitrodopamine (6-ND). The basal release of 6-ND from these tissues was significantly decreased (but not abolished) when the tissues were pre-incubated with Nω-nitro-L-arginine methyl ester (L-NAME). Methods: In this study, the effect of the pharmacological modulation of the redox environment on the basal release of 6-ND was investigated. The basal release of 6-ND was measured using Liquid chromatography with tandem mass spectrometry (LC-MS/MS). Results and Discussion: Pre-incubation (30 min) of the tissues with GKT137831 (1 μM) caused a significant increase in the basal release of 6-ND from all tissues. In the HUA, pre-incubation with diphenyleneiodonium (DPI) (100 μM) also caused significant increases in the basal release of 6-ND. Preincubation of the HUA with hydrogen peroxide (H2O2) (100 μM) increased 6-ND basal release, whereas pre-incubation with catalase (1,000 U/mL) significantly decreased it. Pre-incubation of the HUA with superoxide dismutase (SOD) (250 U/mL; 30 min) also significantly increased the basal release of 6-ND. Preincubation of the HUA with either allopurinol (100 μM) or uric acid (1 mM) had no effect on the basal release of 6-ND. Pre-treatment of the HUA with L-NAME (100 μM) prevented the increase in the basal release of 6-ND induced by GKT137831, diphenyleneiodonium, and H2O2. The results obtained indicate a major role of endogenous H2O2 and peroxidases as modulators of 6- ND biosynthesis/release and a lack of peroxynitrite contribution.

Levosimendan as a treatment for acute renal failure associated with cardiogenic shock after hip fracture

Inotropic drugs are part of the treatment of heart failure; however, inotropic treatment has been largely debated due to the increased incidence of adverse effects and increased mortality. Recently levosimendan, an inotropic positive agent, has been proved to be effective in acute heart failure, reducing the mortality and improving cardiac and renal performance. We report the case of a 75-year-old woman with history of heart and renal failure and hip fracture. Levosimendan was used in preoperative preparation as an adjuvant therapy, to improve cardiac and renal function and to allow surgery.

The myosin activator omecamtiv mecarbil: a promising new inotropic agent

Heart failure became a leading cause of mortality in the past few decades with a progressively increasing prevalence. Its current therapy is restricted largely to the suppression of the sympathetic activity and the renin-angiotensin system in combination with diuretics. This restrictive strategy is due to the potential long-term adverse effects of inotropic agents despite their effective influence on cardiac function when employed for short durations. Positive inotropes include inhibitors of the Na⁺/K⁺ pump, β-receptor agonists, and phosphodiesterase inhibitors. Theoretically, Ca²⁺ sensitizers may also increase cardiac contractility without resulting in Ca²⁺ overload; nevertheless, their mechanism of action is frequently complicated by other pleiotropic effects. Recently, a new positive inotropic agent, the myosin activator omecamtiv mecarbil, has been developed. Omecamtiv mecarbil binds directly to β-myosin heavy chain and enhances cardiac contractility by increasing the number of the active force-generating cross-bridges, presumably without major off-target effects. This review focuses on recent in vivo and in vitro results obtained with omecamtiv mecarbil, and discusses its mechanism of action at a molecular level. Based on clinical data, omecamtiv mecarbil is a promising new tool in the treatment of systolic heart failure.

[Levosimendan as a treatment for acute renal failure associated with cardiogenic shock after hip fracture]

Inotropic drugs are part of the treatment of heart failure; however, inotropic treatment has been largely debated due to the increased incidence of adverse effects and increased mortality. Recently levosimendan, an inotropic positive agent, has been proved to be effective in acute heart failure, reducing the mortality and improving cardiac and renal performance. We report the case of a 75-year-old woman with history of heart and renal failure and hip fracture. Levosimendan was used in preoperative preparation as an adjuvant therapy, to improve cardiac and renal function and to allow surgery.

Levosimendan versus dobutamine in critically ill patients: a meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the clinical efficacy of levosimendan versus dobutamine in critically ill patients requiring inotropic support.

METHODS

Clinical trials were searched in PubMed, EMBASE, and the Cochrane Central Registry of Clinical Trials, as well as Web of Science. Studies were included if they compared levosimendan with dobutamine in critically ill patients requiring inotropic support, and provided at least one outcome of interest. Outcomes of interest included mortality, incidence of hypotension, supraventricular arrhythmias, and ventricular arrhythmias.

RESULTS

Data from a total of 3052 patients from 22 randomized controlled trials (RCTs) were included in the analysis. Overall analysis showed that the use of levosimendan was associated with a significant reduction in mortality (269 of 1373 [19.6%] in the levosimendan group, versus 328 of 1278 [25.7%] in the dobutamine group, risk ratio (RR)=0.81, 95% confidence interval (CI) 0.70-0.92, P for effect=0.002). Subgroup analysis indicated that the benefit from levosimendan could be found in the subpopulations of cardiac surgery, ischemic heart failure, and concomitant β-blocker therapy in comparison with dobutamine. There was no significant difference in the incidence of hypotension, supraventricular arrhythmias, or ventricular arrhythmias between the two drugs.

CONCLUSIONS

In contrast with dobutamine, levosimendan is associated with a significant improvement in mortality in critically ill patients requiring inotropic support. Patients having cardiac surgery, with ischemic heart failure, and receiving concomitant β-blocker therapy may benefit from levosimendan. More RCTs are required to address the questions about no positive outcomes in the subpopulation in a cardiology setting, and to confirm the advantages in long-term prognosis.

Heart Transplantation in a 14-Year-Old Boy in the Presence of Severe Out-of-Proportion Pulmonary Hypertension due to Restrictive Left Heart Disease: A Case Report

A 14-year-old boy after balloon valvuloplasty of severe aortic valve stenosis in the neonatal period was referred for heart-lung transplantation because of high grade pulmonary hypertension and left heart dysfunction due to endocardial fibroelastosis with severe mitral insufficiency. After heart catheterization, hemodynamic parameters were invasively monitored: a course of levosimendan and initiation of diuretics led to a decrease of pulmonary capillary wedge pressure (from maximum 35 to 24 mmHg). Instead of an expected decrease, mean pulmonary artery pressures (mPAP) increased up to 80 mmHg with increasing transpulmonary pressure gradient (TPG) up to 55 mmHg. Oral bosentan and intravenous epoprostenol then led to a ~50% decrease of mPAP (TPG between 16 and 22 mmHg). The boy was listed solely for heart transplantation which was successfully accomplished 1 month later.

The challenge of treating congestion in advanced heart failure

Volume overload is a common manifestation of heart failure decompensation. Interaction between impaired renal and heart function constitutes an important pathophysiologic mechanism that leads to congestion. In addition to improving symptoms and volume status, reduction of rehospitalization rates, maintenance of renal function and improvement of survival are all important goals of every therapeutic strategy. Currently, the use of diuretics, vasodilators, inotropes and ultrafiltration, together with investigational agents such as oral vasopressin antagonists and adenosine A1-receptor antagonists, constitute the main therapeutic options for the congested heart failure patient.

Vasoactive support in the optimization of post-cardiac arrest hemodynamic status: from pharmacology to clinical practice

As a critical component of post-resuscitation care, prompt optimization of hemodynamic status by means of targeted interventions is vital in order to maximize the likelihood of good outcome. Vasoactive agents play an essential role in the supportive care of post cardiac arrest patients. The administration of these agents is associated with serious side-effects and therefore they should be used in the minimal dose necessary to achieve low-normal mean arterial pressure and adequate systematic perfusion. Careful and frequent serial evaluation of the patient is important primarily to assess volume status and adequacy of circulatory support. Continuous monitoring of blood pressure and laboratory parameters is essential both to accurately titrate therapy and because inotropes and vasopressors have the potential to induce life-threatening side-effects. The clinical efficacy of inotropes and vasopressors has been largely investigated through examination of their impact on hemodynamic end points, and clinical practice has been driven in part by expert opinion, extrapolation from animal studies, and physician preference. Clearly these agents should all be considered as supportive measures to stabilize the patient prior to some form of definitive therapy.

[Treatment of progressive heart failure: pharmacotherapy, resynchronization (CRT), surgery]

The treatment of progressive and terminal heart failure follows the principle of causative therapy. Therefore, etiology and pathophysiology of the underlying disease and its hemodynamic conditions are indispensable. This applies to coronary artery disease, hypertension, valvular heart disease, the cardiomyopathies with and without inflammation, and microbial persistence similarly. The classic treatment algorithms both in heart failure with and without reduced ejection fraction are based on measures onloading the heart (angiotensin-converting enzyme inhibitors, angiotensin antagonists, beta-blockers, diuretics) and on antiarrhythmics and anticoagulation, when needed. Device therapy for cardiac resynchronization in left bundle branch block and permanent stimulation therapy may contribute to the hemodynamic benefit. ICD (implantable cardioverter defibrillator) therapy prevents sudden cardiac death, which is often associated with progressive heart failure. Heart transplantation and left ventricular assist devices are final options in the treatment repertoire of terminal heart failure.