Electrophysiologic effects of a calcium sensitizer inotrope levosimendan administered intravenously in patients with normal cardiac function

Successful Combination of Landiolol and Levosimendan in Patients with Decompensated Heart Failure

Tachycardia and supraventricular tachyarrhythmias often impair cardiovascular capacity in patients with decompensated heart failure (dHF) treated with inotropes. Normalization of heart rhythm or rate typically improves diastolic filling and stroke volume (SV). Thus, isochronal administration of an ultra-short-acting and highly selective β₁-blockers, such as landiolol, along with inotropic calcium-sensitizer medications, such as levosimendan, could benefit patients with dHF.We present a case series of three patients with severe dHF and low ejection fraction who were successfully treated with a combination of landiolol and levosimendan. The co-administration of landiolol and levosimendan was well tolerated, improved cardiac function, normalized SV, and enabled the reduction of norepinephrine dosing in all patients. Additionally, the combination improved the vectorcardiographic spatial QRS-T angle and decreased the corrected QT interval. All patients were successfully discharged from the intensive care unit (ICU).A combination of levosimendan and landiolol was safe and well-tolerated. This combination may be a new option for successful treatment of patients with acute dHF complicated by sinus or supraventricular tachycardias.

Cardiac Inotropes Offer Protection of Renal Function in Patients with Kidney Transplantation

INTRODUCTION

Impaired cardiac function is one of the most concomitant symptoms in patients with kidney failure after long-term dialysis. In addition, the preservation of adequate perfusion pressure to the graft plays a significant role in the intraoperative management during kidney transplantation, but the use of positive inotropic drugs in kidney transplant patients has been studied less. We investigated the protective effects of renal function by means of cardiac inotropes in kidney transplant patients.

METHODS

Eighty-nine patients that received kidney transplantation between April 2014 and December 2016 at Qilu Hospital were included and randomly divided into the treatment group receiving levosimendan and a control group. All kidney recipients received ABO-compatible donors. A poor outcome was defined as one of the following: delayed graft function, graft hemorrhage, or nephrectomy.

RESULTS

The treatment group had a better composite outcome and the level of neutrophil gelatinase-associated lipocalin was also lower than in the control group.

CONCLUSION

Inotropic drugs may play a protective role in renal function in kidney transplantation.

Inotropes and cardiorenal syndrome in acute heart failure - A retrospective comparative analysis

INTRODUCTION

Cardiorenal syndrome (CRS) is common in acute heart failure (AHF), and is associated with dire prognosis. Levosimendan, a positive inotrope that also has diuretic effects, may improve patients' renal profile. Published results are conflicting.

OBJECTIVES

We aimed to assess the incidence of CRS in AHF patients according to the inotrope used and to determine its predictors in order to identify patients who could benefit from the most renoprotective inotrope.

METHODS

In a retrospective study, 108 consecutive patients with AHF who required inotropes were divided into two groups according to the inotrope used (levosimendan vs. dobutamine). The primary endpoint was CRS incidence. Follow-up for mortality and readmission for AHF was conducted.

RESULTS

Seventy-one percent of the study population were treated with levosimendan and the remainder with dobutamine. No differences were found in heart failure etiology or chronic kidney disease. At admission, the dobutamine group had lower blood pressure; there were no differences in estimated glomerular filtration rate or cystatin C levels. The levosimendan group had lower left ventricular ejection fraction. CRS incidence was higher in the dobutamine group, and they more often had incomplete recovery of renal function at discharge. In multivariate analysis, cystatin C levels predicted CRS. The dobutamine group had higher in-hospital mortality, of which CRS and the inotrope used were predictors.

CONCLUSIONS

Levosimendan appears to have some renoprotective effect, as it was associated with a lower incidence of CRS and better recovery of renal function at discharge. Identification of patients at increased risk of renal dysfunction by assessing cystatin C may enable more tailored therapy, minimizing the incidence of CRS and its negative impact on outcome in AHF.

Effect of Levosimendan and Milrinone on Regional Myocardial Ischemia/Reperfusion-Induced Arrhythmias in Dogs

Phosphodiesterase inhibitors as inodilators in heart failure are associated with promotion of arrhythmias. Calcium sensitizers have been proposed for the treatment of severe decompensated heart failure. The effect of levosimendan, a calcium sensitizer, and milrinone, a phosphodiesterase inhibitor, on ventricular arrhythmias was compared in a model of acute regional myocardial ischemia and reperfusion. The left anterior descending coronary artery in dogs was occluded for 25 minutes, followed by reperfusion. The 2 drugs were administered in a hemodynamically equieffective dose (0.1 μmol/kg) 10 minutes before coronary occlusion. Levosimendan, but not milrinone, significantly attenuated the pronounced increase in the number of ventricular premature beats (-63%), tachycardia (-50%), fibrillation (-70%), and inhomogeneity of ventricular electrical activation. Levosimendan significantly improved the overall survival rate. Levosimendan has a more beneficial profile than milrinone regarding the development of ventricular arrhythmias during and after regional myocardial ischemia

Oral Levosimendan Increases Cerebral Blood Flow Velocities in Patients with a History of Stroke or Transient Ischemic Attack: A Pilot Safety Study

Background

Intravenous levosimendan is indicated for acute heart failure. The compound has shown promising beneficial effects in ischemic stroke models.

Objective

We evaluated the efficacy and safety of oral levosimendan in patients with a history of cerebral ischemia.

Methods

In a randomized, double-blind, placebo-controlled, parallel-group study, 16 patients with a history of ischemic stroke/transient ischemic attack received oral levosimendan in 5 escalating doses from 0.125 to 2.0 mg daily for 18-day intervals of each dose; 5 patients received placebo. Twenty-four-hour ambulatory ECG and cerebral blood flow velocities using transcranial Doppler ultrasound were recorded at baseline and at the end of each dosing period. Vasomotor reactivity was assessed via the breath holding index. In addition, plasma levels of N-terminal-pro-B-type natriuretic peptide (NT-pro-BNP) and the metabolites of levosimendan were determined.

Results

Levosimendan induced an increase in cerebral blood flow velocities and a decrease in NT-pro-BNP compared with placebo. There was no significant effect on breath holding index. Doses ≥0.5 mg increased heart rate by 5 to 9 beats/min. The dose level of 2.0 mg exceeded the preset safety margin of ventricular extrasystoles per hour (ie, upper 90% CI of the ratio of levosimendan to placebo above 2) with an estimate of 3.10 (90% CI, 0.95–10.07).

Conclusions

Oral levosimendan increases cerebral blood flow velocities and diminishes NT-pro-BNP levels in patients with earlier ischemic cerebrovascular event. Daily doses up to 1.0 mg were well tolerated, whereas the 2.0 mg dose level induced an increase in ventricular extrasystoles. ClinicalTrials.gov identifier: NCT00698763.

Levosimendan: first in a new class of inodilator for acute and chronic severe heart failure

Heart failure is the most common malignant disease in the developed world. Levosimendan (Simdax) is a novel intravenous agent that exerts inotropic effects through sensitization of myofilaments to calcium and vasodilator effects by opening ATP-dependent potassium channels on vascular smooth muscle. Infusion of levosimendan increases cardiac output due to an increase in stroke volume and heart rate, with a fall in pulmonary capillary wedge pressure. It has an active metabolite with a half-life of about 80 h, therefore infusions of 6 to 24 h result in hemodynamic effects that persist for 7 to 10 days. Preliminary observations suggest that a single infusion of levosimendan lasting 6 to 24 h in patients with severe heart failure due to left ventricular systolic dysfunction results in hemodynamic changes, symptomatic benefit and a reduction in morbidity and mortality over the following 2 to 4 weeks compared with placebo in one study and with dobutamine in another. Long-term follow-up suggests no loss of this early benefit over 6 months. Levosimendan is licensed for the treatment of decompensated heart failure in many countries but not in North America. Further large trials are being conducted comparing levosimendan with placebo and with dobutamine in patients with severe heart failure and left ventricular systolic dysfunction. If these studies confirm the benefits of levosimendan, then it may become routine therapy for the management of severe heart failure.

Levosimendan: Implications for Clinicians

Levosimendan is a novel calcium sensitizing agent in development for the treatment of acute and chronic heart failure. The agent increases myocardial force without increasing myocyte calcium concentrations, thus reducing the possibility for myocardial necrosis. In addition, the agent also causes vasodilation of coronary and peripheral vessels to improve coronary blood flow and reduce afterload. The short half-life is a benefit for intravenous administration but could be problematic for the drug's use in chronic heart failure. The risk of the development of arrhythmias from levosimendan appears small secondary to an increase in the QTc interval of 15 msec but needs to be evaluated in light of the ability of levosimendan to open adenosine triphosphate (ATP)-sensitive potassium channels. In addition, the agent has not been studied in patients with additional risks for torsades de pointes. Levosimendan has been shown to have beneficial survival effects in several populations; its use improves patient outcomes relative to the standard of care and has the potential to reduce hospital costs associated with heart failure.

Methodologies to characterize the QT/corrected QT interval in the presence of drug-induced heart rate changes or other autonomic effects

This White Paper, written collaboratively by members of the Cardiac Safety Research Consortium from academia, industry, and regulatory agencies, discusses different methods to characterize the QT effects for drugs that have a substantial direct or indirect effect on heart rate. Descriptions and applications are provided for individualized QT-R-R correction, Holter bin, dynamic QT beat-to-beat, pharmacokinetic-pharmacodynamic modeling, and QT assessment at constant heart rate. Most of these techniques are optimally performed using continuous electrocardiogram data obtained in clinical studies designed to characterize a drug's effect on the QT interval. An important study design element is the collection of drug-free data over a range of heart rates seen on treatment. The range of heart rates is increased at baseline by using ambulatory electrocardiogram recordings in addition to those collected under semisupine, resting conditions. Discussions in this study summarize areas of emerging consensus and other areas in which consensus remains elusive and provide suggestions for additional research to further increase our knowledge and understanding of this topic.

Efficiency and safety of prolonged levosimendan infusion in patients with acute heart failure

Background. Levosimendan is an inotropic drug with unique pharmacological advantages in patients with acute heart failure. Scope of this study is to determine whether longer infusion patterns without the hypotension-inducing loading dose could justify an effective and safe alternative approach. Methods. 70 patients admitted to the emergencies with decompensated chronic heart failure received intravenously levosimendan without a loading dose up to 72 hours. Clinical parameters, BNP (Brain Natriuretic Peptide) and signal-averaged-ECG data (SAECG) were recorded up to 72 hours. Results. The 48-hour group demonstrated a statistically significant BNP decrease (P < .001) after 48 hours, which also maintained after 72 hours. The 72-hour group demonstrated a bordeline decrease of BNP after 48 hours (P = .039), necessitating an additional 24-hour infusion to achieve significant reduction after 72 hours (P < .004). SAECG data demonstrated a statistically significant decrease after 72 hours (P < .04). Apart from two deaths due to advanced heart failure, no major complications were observed. Conclusion. Prolonged infusion of levosimendan without a loading dose is associated with an acceptable clinical and neurohumoral response.

Levosimendan - a calcium sensitising agent with potential anti-arrhythmic properties

Levosimendan is a 'Ca(2+)sensitiser', which exerts its inotropic effect by increasing the affinity of troponin C for Ca(2+), directly stabilising the Ca(2+)-induced conformation of troponin C. It leads to a positive inotropic effect without impairing diastolic relaxation and causing cytosolic Ca(2+) ion overload, which might result in cardiac myocyte dysfunction, arrhythmias and cell death. Levosimendan may also have significant anti-inflammatory properties. Data from various studies suggest that levosimendan might have anti-arrhythmic effects, although the outcome of clinical trials on the effect of this agent in (for example) atrial fibrillation (AF) remains controversial. Currently, on the basis of available data, it is especially worth emphasising the potential role of this drug in the termination of AF after cardiac surgery, which significantly influences early- and long-term morbidity and mortality. This review considers the putative anti-arrhythmic properties of levosimendan and discusses the potential clinical application of such a drug.

Inoprotection: the perioperative role of levosimendan

Levosimendan is emerging as a novel cardioprotective inotrope. Levosimendan augments myocardial contractility by sensitising contractile myofilaments to calcium without increasing myosin adenosine triphosphatase activity or oxygen consumption. Levosimendan activates cellular adenosine triphosphate-dependent potassium channels, a mechanism which is postulated to protect cells from ischaemia in a manner similar to ischaemic preconditioning. Levosimendan may therefore protect the ischaemic myocardium during ischaemia-reperfusion as well as improve the contractile function of the heart. Adenosine triphosphate-dependent potassium channel activation by levosimendan may also be protective in other tissues, such as coronary vascular endothelium, kidney and brain. Clinical trials in patients with decompensated heart failure and myocardial ischaemia show levosimendan to improve haemodynamic performance and potentially improve survival. This paper reviews the known pharmacology of levosimendan, the clinical experience with the drug to date and the potential use of levosimendan as a cardioprotective agent during surgery.

[Role of Levosimendan in intensive care treatment of myocardial insufficiency]

Levosimendan is a calcium sensitizer that is currently in the focus of intensive care medicine because it may be superior to standard inotropic agents in the treatment of acute myocardial insufficiency. The effects of levosimendan mainly depend on three predominant mechanisms: 1) positive inotropic effect by increasing the sensitivity of cardiac myofilaments to calcium ions, 2) vasodilatory effect by stimulation of adenosine triphosphate-sensitive potassium channels and 3) inhibition of phosphodiesterase-III. In a large number of experimental and clinical studies further possible indications for levosimendan have been described, e.g. cardioprotection during ischemia, cardiogenic shock, septic myocardial insufficiency and pulmonary hypertension. This review article critically summarizes the current scientific and clinical knowledge about levosimendan, its pharmacologic characteristics, mechanisms of action as well as indications and potential risks.

Clinical pharmacology of levosimendan

Levosimendan has been developed for the treatment of decompensated heart failure and is used intravenously when patients with heart failure require immediate initiation of drug therapy. It increases cardiac contractility and induces vasodilatation. The pharmacokinetics of levosimendan are linear at the therapeutic dose range of 0.05-0.2 microg/kg/minute. The short half-life (about 1 hour) of the parent drug, levosimendan, enables fast onset of drug action, although the effects are long-lasting due to the active metabolite OR-1896, which has an elimination half-life of 70-80 hours in patients with heart failure (New York Heart Association functional class III-IV). Although levosimendan is administered intravenously, it is excreted into the small intestine and reduced by intestinal bacteria to an amino phenolpyridazinone metabolite (OR-1855). This metabolite is further metabolised by acetylation to N-acetylated conjugate (OR-1896). The circulating metabolites OR-1855 and OR-1896 are formed slowly, and their maximum concentrations are seen on average 2 days after stopping a 24-hour infusion. The haemodynamic effects after levosimendan seem to be similar between fast and slow acetylators despite the fact that the enzyme N-acetyltransferase-2, which is responsible for the metabolism of OR-1855 to OR-1896, is polymorphically distributed in the population. Levosimendan reduces peripheral vascular resistance and has direct contractility-enhancing effects on the failing left ventricle. It also improves indices of diastolic function and seems to improve the function of stunned myocardium. Despite an improvement in ventricular function, levosimendan does not increase myocardial oxygen uptake significantly. An increase in coronary blood flow and a reduction in coronary vascular resistance have been observed. Levosimendan reduces plasma brain natriuretic peptide (BNP) and N-terminal pro-BNP (NT-proBNP) levels substantially, and a decrease in plasma endothelin-1 has been observed. Levosimendan also exerts beneficial effects on proinflammatory cytokines and apoptosis mediators. The effects of a 24-hour levosimendan infusion on filling pressure, ventricular function and BNP, as well as NT-proBNP, last for at least 7 days.

Pharmacological preconditioning by levosimendan is mediated by inducible nitric oxide synthase and mitochondrial KATP channel activation in the in vivo anesthetized rabbit heart model

BACKGROUND

Provocation of fatal cardiac arrhythmias has limited the use of inotropic agents as heart failure therapy. Levosimendan (LEV) is a new inodilator, whose mechanism of action includes calcium sensitization of contractile proteins and the opening of ATP-dependent potassium channels.

OBJECTIVES AND METHODS

The aim of this investigation was to test whether the administration of LEV has cardioprotective and antiarrhythmic effects against ischemia and reperfusion injury in a manner similar to ischemic preconditioning (IPC) in a well-standardized model of reperfusion arrhythmias in anesthetized adult male rabbits (n=122) subjected to 30 min occlusion of the left coronary artery followed by 120 min of reperfusion.

RESULTS

Pretreatment with either 1 cycle of IPC, LEV (0.1 micromol/kg, i.v.), or IPC+LEV prior to the period of coronary occlusion offers significant infarct size reduction (21.6+/-1.6%, 22.1+/-2.2%, and 21.4+/-1.4%, respectively vs 38.7+/-3.6% in saline control group; P<0.01) and antiarrhythmic effects. IPC, LEV and IPC+LEV treatment significantly attenuated the incidence of life-threatening arrhythmias like sustained VT (13%, 13% and 13%, respectively vs 100% in saline control group; P<0.005) and other arrhythmias (25%, 25% and 13%, respectively vs 100% in saline control group; P<0.005), and increased the number of surviving animals without arrhythmias. Pretreatment with 5-HD, N(omega)-nitro-L-arginine methyl ester (L-NAME, a nonspecific NOS inhibitor) and the specific iNOS inhibitor 1400 W [N-(-3-(aminomethyl)benzyl) acetamidine] abolished the beneficial effects of IPC, and LEV on reperfusion induced arrhythmias and cardioprotection suggesting that benefits have been achieved via both the selective activation of cardiomyocyte mitochondrial K(ATP) channels and NO. One cycle of IPC and LEV pretreatment significantly preserved the level of ATP in the 30 min ischemic heart and 120 min reperfused heart.

CONCLUSIONS

The present study demonstrates similarities between acute LEV treatment and IPC of the rabbit myocardium in terms of survival, cardioprotection, antiarrhythmic activity, and metabolic status.

A review of levosimendan in the treatment of heart failure

Heart failure is a relatively important public health problem due to its increasing incidence, poor prognosis, and frequent need of re-hospitalization. Intravenous positive inotropic agents play an important role in treating acute decompensation of patients with heart failure due to left ventricular systolic dysfunction. Although frequently used, the inotropic agents β-adrenergic agonists and phosphodiesterase inhibitors seem effective for improving symptoms in the short term; it has been shown that they increase morbidity and mortality by elevating intracellular cyclic adenosine monophosphate (cAMP) and calcium levels. Levosimendan is a new positive inotropic agent having ATP-dependent potassium-channel-opening and calcium-sensitizing effects. In studies on its effects without increasing intracellular calcium concentrations and on its effects that depend on available intracellular calcium levels, it has been shown to have favorable characteristics different from those of current inotropic agents, which exert their effects by increasing calcium concentrations. This study aims to review other important studies about levosimendan by revealing the underlying mechanisms of its activity, efficiency, and safety.

Levosimendan: beyond its simple inotropic effect in heart failure

Classic inotropic agents provide short-term haemodynamic improvement in patients with heart failure, but their use has been associated with poor prognosis. A new category of inotropic agents, the Ca(2+) sensitizers, may provide an alternative longer lasting solution. Levosimendan is a relatively new Ca(2+) sensitizer which offers haemodynamic and symptomatic improvement by combining a positive inotropic action via Ca(2+) sensitization and a vasodilatory effect via adenosine triphosphate(ATP)-sensitive K(+) (K(ATP)), Ca(2+)-activated K(+) (K(Ca)(2+)) and voltage-dependent K(+) (K(V)) channels activation. Levosimendan also seems to induce a prolonged haemodynamic improvement in patients with heart failure as a result of the long half-life of its active metabolite, OR-1896. Furthermore, there is also evidence that levosimendan may have additional antiinflammatory and antiapoptotic properties, affecting important pathways in the pathophysiology of heart failure. Despite the initial reports for a clear benefit of levosimendan on short- and long-term mortality in patients with severe heart failure, the results from the recent clinical trials are rather disappointing, and it is still unclear whether it is superior to dobutamine in affecting survival of patients with severe heart failure. In conclusion, levosimendan is a promising agent for the treatment of decompensated heart failure. As further to its positive inotropic effect, it affects multiple pathways with key roles in the pathophysiology of heart failure. The results of the ongoing trials examining the effect of levosimendan on mortality in patients with heart failure will hopefully resolve the controversy as to whether levosimendan is superior to classic inotropic agents for the treatment of severe heart failure.

The utility of levosimendan in the treatment of heart failure

Calcium sensitizers are a new group of inotropic drugs. Levosimendan is the only calcium sensitizer in clinical use in Europe. Its mechanism of action includes both calcium sensitization of contractile proteins and the opening of adenosine triphosphate (ATP)-dependent potassium channels as mechanism of vasodilation. The combination of K-channel opening with positive inotropy offers potential benefits in comparison to currently available intravenous inotropes, since K-channel opening protects myocardium during ischemia. Due to the calcium-dependent binding of levosimendan to troponin C, the drug increases contractility without negative lusitropic effects. In patients with heart failure levosimendan dose-dependently increases cardiac output and reduces pulmonary capillary wedge pressure. Since levosimendan has an active metabolite OR-1896 with a half-life of some 80 hours, the duration of the hemodynamic effects significantly exceeds the 1-hour half-life of the parent compound. The hemodynamic effects of the levosimendan support its use in acute and postoperative heart failure. Several moderate-size trials (LIDO, RUSSLAN, CASINO) have previously suggested that the drug might even improve the prognosis of patients with decompensated heart failure. These trials were carried out in patients with high filling pressures. Recently two larger trials (SURVIVE and REVIVE) in patients who were hospitalized because of worsening heart failure have been finalized. These trials did not require filling pressures to be measured. The two trials showed that levosimendan improves the symptoms of heart failure, but does not improve survival. The results raise the question whether a 24-hour levosimendan infusion can be used without invasive hemodynamic monitoring.

Pharmacological Mechanisms Contributing to the Clinical Efficacy of Levosimendan

Acute decompensation of chronic heart failure is a direct life-threatening situation with short-term mortality approaching 30%. A number of maladaptive changes are amplified within the cardiovascular system during the progression of chronic heart failure that makes the decompensation phase difficult to handle. Levosimendan is a new Ca2+-sensitizer for the treatment of acutely decompensated heart failure that has proved to be effective during the decompensation of chronic heart failure and acute myocardial infarction. Levosimendan differs from other cardiotonic agents that are used for acute heart failure in that it utilizes a unique dual mechanism of action: Ca2+-sensitization through binding to troponin C in the myocardium, and the opening of ATP-sensitive K+ channels in vascular smooth muscle. In general, these mechanisms evoke positive inotropy and vasodilation. Clinical studies suggested long-term benefits on mortality following short-term administration. It may, therefore, be inferred that levosimendan has additional effects on the cardiovascular system that are responsible for the prolongation of survival. Results of preclinical and clinical investigations suggest that the combination of levosimendan-induced cardiac and vascular changes has favorable effects on the coronary, pulmonary and peripheral circulations. Redistribution of the circulating blood offers an improved hemodynamic context for the development of a positive inotropic effect through Ca2+-sensitization of the contractile filaments, without a proportionate increase in myocardial oxygen consumption or the development of arrhythmias. Activation of ATP-sensitive K+ channels, both on sarcolemma and mitochondria, may protect against myocardial ischemia, and decreased levels of cytokines may prevent the development of further myocardial remodeling. Collectively, these effects of levosimendan shift the disturbed cardiovascular parameters towards normalization, thereby halting the perpetuation of the vicious cycle of heart failure progression. This may contribute to stabilization of the circulation and improved life expectancy of patients with chronic heart failure.

Levosimendan protects against experimental endotoxemic acute renal failure

Endotoxemia induces a hemodynamic form of acute renal failure (ARF; renal vasoconstriction +/- reduced glomerular ultrafiltration coefficient, K(f); minimal/no histological damage). We tested whether levosimendan (LS), an ATP-sensitive K+ (K(ATP)) channel opener with cardiac ionotropic and possible anti-inflammatory properties, might have utility in combating this form of ARF. CD-1 mice were injected with LPS +/- LS. LS effects on LPS-induced systemic inflammation (plasma TNF-alpha/MCP-1; cardiorenal mRNAs), plasma NO levels, and azotemia were assessed. Because K(ATP) channel opening has been reported to mediate hypoxic tubular injury, possible adverse LS effects on ischemic ARF and ATP depletion injury were sought. Effects of diazoxide (another K(ATP) channel agonist) and glibenclamide (a channel antagonist) on hypoxic tubular injury also were assessed. Finally, the ability of LS to alter rat mesangial cell (MC) contraction in response to ANG II (elevated in sepsis) was tested. LS conferred almost complete protection against LPS-induced ARF, without any apparent reduction in the LPS-induced inflammatory response. Neither LS nor diazoxide altered ATP depletion-mediated tubule injury (in vivo or in vitro). Conversely, glibenclamide induced a marked and direct cytotoxic effect. LS completely blocked ANG II-induced MC contraction, an action likely to increase K(f). We concluded that 1) LS can confer marked protection against LPS-induced ARF; 2) this likely stems from vasoactive properties, rather than reductions in LPS-induced inflammation; and 3) K(ATP) channel agonists (but not antagonists) appear to be devoid of toxic proximal tubular cell effects. This suggests that LS, and other K(ATP) channel agonists, have a margin of safety if employed in situations (sepsis syndrome, heart failure) in which severe renal vasoconstriction might lead to ischemic ARF.

Levosimendan for the treatment of acute heart failure syndromes

Levosimendan is a novel calcium-sensitising agent that has been shown to have beneficial inotropic, metabolic and vasodilatory effects in the treatment of acute and advanced chronic heart failure. Levosimendan binds to troponin-C in cardiomyocytes and, thereby, improves cardiac contractility without disturbing the metabolic status of the heart and increasing myocardial oxygen demand or provoking fatal cardiac arrhythmias. Levosimendan also opens ATP-sensitive potassium channels, causing peripheral arterial and venous dilatation, and increasing coronary flow reserve. When it is given as a short-term therapy, levosimendan enhances cardiac output, reduces systemic vascular resistance and lowers pulmonary capillary wedge pressure. Clinical outcomes were significantly reduced in decompensated or postmyocardial infarction heart failure patients who received levosimendan, compared with those on dobutamine or placebo. Recent investigations focusing on the anti-inflammatory and antiapoptotic actions of levosimendan in the failing heart indicate that improvement of cardiac contractile performance is closely related with the drug-induced reduction of circulating pro-inflammatory cytokines and apoptosis inducers. The most common adverse effects of levosimendan treatment are hypotension and headache. Overall, levosimendan represents an effective and safe option for the treatment of decompensated heart failure patients.

Levosimendan: a novel inotropic agent for treatment of acute, decompensated heart failure

OBJECTIVE

To review the literature on a novel calcium sensitizer, levosimendan.

DATA SOURCES

Articles were identified through searches of MEDLINE (1966-June 2005), International Pharmaceutical Abstracts (1970-June 2005), and EMBASE (1992-June 2005) using the key words levosimendan, simendan, calcium sensitizer, calcium sensitiser, and congestive heart failure.

STUDY SELECTION AND DATA EXTRACTION

Clinical trials and pharmacokinetic studies evaluating the safety and efficacy of levosimendan were selected.

DATA SYNTHESIS

Levosimendan 6-24 mug/kg intravenous bolus followed by a 24-hour continuous infusion of 0.05-0.2 microg/kg/min improved cardiac output and reduced pulmonary capillary wedge pressure in a dose-dependent manner. Dose-ranging and randomized clinical trials have demonstrated improvement in symptoms and hemodynamics and short-term survival outcomes in the treatment of acute, decompensated heart failure. Clinical trials evaluating retrospective mortality data and combined endpoints (mortality, rehospitalization) have demonstrated better outcomes with levosimendan compared with dobutamine. The incidence of hypotension with levosimendan is not significantly different than with dobutamine, but there is a dose-related increase in heart rate.

CONCLUSIONS

Levosimendan is useful in moderate to severe low-output heart failure in patients who have failed to respond to diuretics and vasodilators. Based on current studies, levosimendan appears to be a safe alternative to dobutamine for treatment of acute, decompensated heart failure. Prospective clinical trials are needed to confirm the effect of levosimendan on long-term survival and its role in heart failure in the setting of myocardial infarction.

Levosimendan: a calcium-sensitizing agent for the treatment of patients with decompensated heart failure

Levosimendan is a new inodilator. Its mechanism of action includes calcium sensitization of contractile proteins and the opening of adenosine triphosphate-dependent K channels. The combination of positive inotropy with anti-ischemic effects of K-channel opening offers potential benefits in comparison with currently available intravenous inotropes, which are contraindicated in patients with ongoing myocardial ischemia. Levosimendan has been extensively studied in various animal models of heart failure, in which the drug has increased contractility without adverse effects on diastolic function. These results have been repeated in patients with heart failure, in whom levosimendan dose-dependently increases cardiac output and reduces pulmonary capillary wedge pressure. The active metabolite of levosimendan (OR-1896) significantly prolongs the duration of the hemodynamic effects of the therapeutic 24-hour levosimendan infusion. Levosimendan has been studied in two major trials with decompensated patients (LIDO and RUSSLAN), in which it showed outcome benefits in comparison with dobutamine and placebo, respectively. A third comparative study (CASINO) recently suggested mortality benefits with levosimendan over placebo and dobutamine. Currently, two large prospective trials (SURVIVE and REVIVE) in patients who are hospitalized because of worsening heart failure are underway. These trials will conclusively prove whether levosimendan should be added to the standard treatment in patients who are hospitalized because of cardiac decompensation.

Levosimendan, a New Calcium-Sensitizing Inotrope for Heart Failure

Calcium sensitizers are a new class of inotropes that share the in vitro properties of calcium sensitization and phosphodiesterase inhibition. Levosimendan is a distinct calcium sensitizer, as it stabilizes the interaction between calcium and troponin C by binding to troponin C in a calcium-dependent manner, improving inotropy without adversely affecting lusitropy. It does not exhibit clinically relevant phosphodiesterase inhibition at therapeutic concentrations. It also exerts vasodilatory effects, possibly through activation of several potassium channels and other less well characterized mechanisms. The pharmacokinetics of levosimendan are similar in healthy subjects and patients with heart failure and remain relatively unaltered by age, sex, and organ dysfunction. In preclinical and clinical studies, levosimendan exerted potent dose-dependent positive inotropic and vasodilatory activity. Unlike conventional inotropes, levosimendan is not associated with significant increases in myocardial oxygen consumption, proarrhythmia, or neurohormonal activation. The most common adverse effects are attributable to the vasodilation. Two large, double-blind, randomized trials demonstrated favorable hemodynamic effects, improved tolerability, and a possible mortality benefit over dobutamine and placebo in patients who had acute symptoms of failure and required inotropic therapy. The long-term effect on patient outcomes is being confirmed in ongoing placebo- and inotrope-controlled trials. Levosimendan appears to be an effective inodilator devoid of the detrimental effects of conventional inotropes. In the future, levosimendan may provide a promising alternative to conventional inotropes for patients with acutely decompensated heart failure.

Resumption of Atrioventricular Conduction by Levosimendan After Radiofrequency Ablation of the AV Node:. Does Levosimendan Have Potential as Medical Therapy in Atrioventricular Conduction Disease?

We report the case of a patient in whom radiofrequency catheter ablation of the AV node was initially successfully performed for persistent atrial fibrillation with fast ventricular rate, but in whom atrioventricular conduction transiently resumes following therapy with levosimendan. Plausible hypothesis are discussed as well as potential implications.

Levosimendan: a review of its use in the management of acute decompensated heart failure

Levosimendan (Simdax) is a calcium-sensitising drug that stabilises the troponin molecule in cardiac muscle, thus prolonging its effects on contractile proteins, with concomitant vasodilating properties. Intravenous levosimendan (12-24 microg/kg loading dose followed by 0.1-0.2 microg/kg/min for 24 hours, adjusted for response and tolerability) is approved for the short-term treatment of acute severe decompensated heart failure. Cardiac output increased by about 30% and pulmonary capillary wedge pressure and systemic vascular resistance decreased by about 17-29% in patients with decompensated heart failure receiving intravenous levosimendan. In large, well controlled trials in patients with decompensated heart failure, intravenous levosimendan was significantly more effective than placebo or dobutamine for overall haemodynamic response rate (primary endpoint). Significant benefits were also seen for mortality (versus placebo or dobutamine) and for the combined risk of worsening heart failure or death (versus dobutamine). Improvements in key symptoms (dyspnoea and fatigue) have not been consistently demonstrated. Hospitalisation costs were similar for levosimendan and dobutamine; the total incremental (hospitalisation plus drug) cost per life-year saved (extrapolated to 3 years) for levosimendan relative to dobutamine was estimated at Euro 3205 (year of costing 2000). Levosimendan is generally well tolerated, with an adverse event profile at recommended dosages similar to that in patients receiving placebo. Cardiac rate/rhythm disorders and headache were the most common events. At higher dosages, patients receiving levosimendan had higher rates of sinus tachycardia than those in placebo recipients. More patients receiving dobutamine than those receiving levosimendan experienced angina pectoris/chest pain/myocardial ischaemia or rate/rhythm disorders.

CONCLUSION

Intravenous levosimendan is an effective calcium-sensitising drug with vasodilatory and inotropic effects, and superior efficacy/tolerability to those of intravenous dobutamine in patients with acute decompensated heart failure. It may be associated with reduced mortality compared with both placebo and dobutamine. Levosimendan is generally well tolerated and may have less potential for cardiac rate/rhythm disorders than dobutamine. While evidence from well designed trials confirming the improved mortality over dobutamine and investigating haemodynamic efficacy and mortality versus other positive inotropes is required, intravenous levosimendan appears to be a useful addition to the treatment options for acute decompensated heart failure in patients with low cardiac output.

Acute decompensated heart failure: a contemporary approach to pharmacotherapeutic management

Hospital admissions for acute decompensated heart failure (ADHF) have increased precipitously during the past few decades and are projected to continue to increase in the future. To optimize patient outcomes and reduce the costs associated with this disorder, evidenced-based pharmacotherapy is essential. Continuous infusions of loop diuretic therapy rather than bolus dosing may enhance efficacy and reduce the extent of diuretic resistance. Nesiritide is a pharmacologically novel preload and afterload reducer but based on clinical trial evidence should be reserved for those unable to take or with resistance to intravenous nitrate therapy. Catecholamine- and phosphodiesterase-based inotropic therapies are efficacious, but the increased risk of arrhythmogenesis and the potential for negative survival effects limit their use. The experimental agent levosimendan is a positive inotropic agent but does not increase myocyte calcium concentrations as do catecholamines or phosphodiesterase inhibitors. Clinical trial evidence demonstrates a positive survival benefit for levosimendan versus dobutamine.

Pharmacotherapeutic approaches for decompensated heart failure: a role for the calcium sensitiser, levosimendan?

Although no universal definition exists, decompensated heart failure may be regarded as either a worsening of chronic heart failure or new-onset heart failure precipitated by an acute incident. Haemodynamic management of patients hospitalised with decompensated heart failure may include the administration of diuretics, vasodilators and positive inotropic agents. Until recently, these latter agents constituted the only drug class to produce a direct increase in stroke volume via enhanced myocardial contractility. However, despite their short-term benefits, the clinical utility of inotropic agents is compromised by their potentially deleterious effects on calcium handling and oxygen consumption, resulting in an increased risk of serious ventricular arrhythmias and death. In contrast, calcium sensitisers enhance cardiac performance without affecting calcium movement and, therefore, are potentially associated with a reduced risk of rhythmic disturbances. These agents constitute a heterogeneous group of compounds with different affinities for calcium sensitisation. Levosimendan is a potent calcium sensitiser with vasodilating properties that has been shown to provide symptomatic and haemodynamic improvement with no increase in oxygen consumption. Calcium sensitisation is therefore emerging as a promising treatment approach in this challenging therapeutic area.

Levosimendan: a new era for inodilator therapy for heart failure?

Levosimendan is a new inotropic and vasodilator agent. The inotropic effect is mediated by calcium concentration-dependent conformational changes in troponin C during systole leading to sensitization of the contractile apparatus to calcium ions. The vasodilator effect is mediated by opening potassium channels on vascular smooth muscle. It has a complex pharmacokinetic profile, with a long-acting metabolite that has hemodynamic effects persisting for approximately 1 week. Although it is absorbed orally, it has been developed only for intravenous use thus far. The hemodynamic effects are not reduced and may be enhanced in the presence of beta-blockers, possibly an important attribute when dealing with exacerbation of heart failure caused by or in the presence of beta-blockers. More patients with heart failure have participated in randomized controlled trials of levosimendan than of any other intravenous inotropic agent. Experience with its use after cardiac surgery is limited. Preliminary observations suggest that hemodynamic changes are associated with symptomatic benefit and a reduction in morbidity and mortality in patients with severe heart failure caused by left ventricular systolic dysfunction, compared with placebo in one study and dobutamine in another. Levosimendan may be the first inotropic agent that it is both safe and effective in altering clinical outcomes relevant for patients. Part of this benefit may be achieved because levosimendan allows other inotropic agents that may have adverse effects on patient outcome to be avoided. Further research is required to confirm whether levosimendan reduces mortality and morbidity compared with a placebo and when administered repetitively. If it does, it may become routine therapy for the treatment of severe heart failure.

Pharmacodynamics and safety of a new calcium sensitizer, levosimendan, and its metabolites during an extended infusion in patients with severe heart failure

Levosimendan is a new calcium sensitizer developed for the short-term intravenous treatment of congestive heart failure. The aims of the present open-label, nonrandomized study were to determine the tolerability, hemodynamic effects, and the basic pharmacokinetics of levosimendan and its metabolites during an extended continuous infusion of levosimendan. Twenty-four patients with New York Heart Association (NYHA) III-IV heart failure in two groups of 12 patients were exposed to either 0.05 microg/kg/min or 0.1 microg/kg/min of levosimendan for 7 days. Heart rate and blood pressure were measured, and blood samples for the determination of plasma concentrations of the parent drug and its metabolites were drawn daily during the infusion and the 10 to 15 days' follow-up. The 7-day infusion was well tolerated and no premature discontinuations occurred. Both systolic and diastolic blood pressure decreased maximally by 6 mmHg in the lower and by 11 mmHg in the higher levosimendan dose groups during the infusion period (p < 0.05 for both groups). The mean heart rate values increased maximally by 18 and 26 beats/min in the lower and higher levosimendan dose groups, respectively (p < 0.001 for both groups). The hemodynamic effects peaked at the end of the infusion period and thereafter slowly declined during the follow-up. After the recommended infusion period of 24 hours, the mean heart rate increase was only 2 and 6 beats/min in the lower and higher levosimendan dose groups, respectively. The elimination half-life of levosimendan was approximately 1 hour and of the metabolites 70 to 80 hours. It can be concluded that levosimendan, even administered considerably longer than the recommended 24 hours, was well tolerated. The 7-day infusion induced a prolonged increase in heart rate and a minor decrease in blood pressure. The long-lasting effects are probably explained by the active metabolite.

The new compound, LASSBio 294, increases the contractility of intact and saponin-skinned cardiac muscle from Wistar rats

1. A new compound designated as LASSBio 294 (L-294), 3,4-methylenedioxybenzoyl-2-thienylhydrazone, was synthesized as an alternative therapeutic for cardiac dysfunction. 2. L-294 increased in a dose-dependent manner the spontaneous contractions of isolated hearts from Wistar rats with maximal effect (128.0+/-0.7% of control) observed at 25 microM. 3. The positive inotropic effect of L-294 was also observed in electrically stimulated cardiac tissues from Wistar rats. The maximal increment of twitches, at 200 microM, was 163.1+/-18.4% for atrial, 153.5+/-28.5% for papillary and 201.5+/-18.5% for ventricular muscles. 4. In saponin skinned ventricular cells: (a) L-294 present in the period of sarcoplasmic reticulum (SR) loading with Ca(2+) shifted the dose and caffeine-induced contracture curve; (b) L-294 (100 microM) increased 40% the Ca(2+) uptake into SR; (c) L-294 did not significantly alter the sensitivity of contractile proteins to Ca(2+) in SR-disrupted skinned ventricular cells. 5. Retrograde perfusion of the isolated heart from Wistar rats with L-294 (100 microM) did not cause any significant change in rhythm, heart rate (control, 220+/-14.7 b.p.m.; 246+/-24.6 b.p.m. for L-294), PR interval (control, 66.0+/-2.4 ms; 64.0+/-2.3 ms for L-294) or QRS duration (control, 28.8+/-3.4 ms; 32.0+/-2.0 ms for L-294). 6. These results suggest a novel mechanism for a positive cardioinotropic effect through an interaction with the Ca(2+) uptake/release process of the SR. The effect of L-294 could be explained by a pronounced increased accumulation of Ca(2+) into the SR.

Levosimendan

Levosimendan, a pyridazinone-dinitrile derivative, is a calcium sensitiser with additional action on adenosine triphosphate (ATP)-sensitive potassium channels. It is used intravenously (IV) for the treatment of decompensated cardiac failure. At therapeutic doses, levosimendan exhibits enhanced contractility with no increase in oxygen demands. It also produces antistunning effects without increasing myocardial intracellular calcium concentrations or prolonging myocardial relaxation. Levosimendan also causes coronary and systemic vasodilation. In patients with decompensated congestive heart failure (CHF), IV levosimendan significantly reduced the incidence of worsening CHF or death. IV levosimendan significantly increased cardiac output or cardiac index and decreased filling pressure in the acute treatment of stable or decompensated CHF in large, double-blind, randomised trials and after cardiac surgery in smaller trials. Levosimendan is well tolerated, with the most common adverse events (headache, hypotension, nausea) being secondary to vasodilation. It has not been shown to be arrhythmogenic. Levosimendan has shown no clinically important pharmacokinetic interactions with captopril, felodipine, beta-blockers, digoxin, warfarin, isosorbide-5-mononitrate, carvedilol, alcohol (ethanol) or itraconazole.

Levosimendan: a parenteral calcium-sensitising drug with additional vasodilatory properties

Levosimendan (Simdax) is a new inodilator developed specifically for the treatment of decompensated heart failure. Its inotropic mechanism is based on calcium sensitisation of myofilaments and its vasodilator actions are related to the opening of ATP-dependent K-channels in the vasculature. Since the inotropic action of levosimendan does not require an increase in cytosolic free calcium, it is less arrhythmogenic than the conventional parenteral beta-agonist inotropes or PDE III inhibiting drugs. Due to the calcium-dependent binding of the drug to troponin C, levosimendan, unlike some other calcium-sensitising drugs, does not prolong diastolic relaxation of the myocytes but acts in synergy with the intramyocellular calcium levels. Furthermore, due to the anti-ischaemic effects of the K-channel opening in myocytes, levosimendan can be used during myocardial ischaemia. In clinical trials, levosimendan has dose-dependently increased cardiac output and decreased pulmonary capillary wedge pressure in patients with heart failure. On the other hand, it also increases heart rate and decreases blood pressure in these patients. In major clinical trials, where patients with decompensated heart failure have been treated with levosimendan, a reduction of overall mortality in comparison to placebo or dobutamine has been seen. This interesting finding should be verified in prospective outcome trials. In any case, the safety of levosimendan during myocardial ischaemia makes this drug valuable in the short-term treatment of decompensated heart failure.