Pharmacology of new agents for acute heart failure syndromes

Relaxin abrogates genomic remodeling of the aged heart

"Healthy" aging drives structural and functional changes in the heart including maladaptive electrical remodeling, fibrosis and inflammation, which lower the threshold for cardiovascular diseases such as heart failure (HF) and atrial fibrillation (AF). Despite mixed results in clinical trials, Relaxin-therapy for 2-days reduced mortality by 37% at 180-days post-treatment, in patients with acute decompensated HF. Relaxin's short lifespan (2-3h) but long-lasting protective actions suggested that relaxin acts at a genomic level to reverse maladaptive remodeling in AF, HF and aging. Our recent studies showed that a 2-week treatment with Relaxin (0.4mg/kg/day) of aged (24months old F-344 rats) increases the expression of voltage-gated Na⁺ channels (mRNA, Nav1.5 and I_Na), connexin-43, abrogates inflammatory and immune responses and reverses myocardial fibrosis and cellular hypertrophy of the aged hearts. Relaxin acts directly at a wide range of cell types in the cardiovascular system that express its cognate GPCR receptor, RXFP1. RNA-seq analysis of young and aged hearts with and without Relaxin treatment revealed that "normal" aging altered the expression of ~10% of genes expressed in the ventricles, including: ion channels, components of fibrosis, hemodynamic biomarkers, immune and inflammatory responses which were reversed by Relaxin. The extensive cardiovascular remodeling caused by Relaxin was mediated through the activation of the Wnt/β-catenin signaling pathway which was otherwise suppressed by in adult cardiomyocytes intracellular by cytosolic Dickkopf1 (Dkk1). Wnt/β-catenin signaling is a mechanism that can explain the pleiotropic actions of Relaxin and the marked reversal of genomic changes that occur in aged hearts.

Levosimendan and Global Longitudinal Strain Assessment in Sepsis (GLASSES 1): a study protocol for an observational study

INTRODUCTION

Cardiogenic shock is a condition of low cardiac output that represents the end stage of a progressive deterioration of cardiac function. The main cause is ischaemic heart disease, but there are several non-ischaemic causes, including sepsis. The use of levosimendan in cardiogenic shock during sepsis is still under debate.

METHODS

We are conducting an observational, single-centre, not-for-profit study enrolling patients aged 18-80 years old admitted to the intensive care unit with a diagnosis of septic shock. Patients will be monitored with the EV1000/VolumeView device (Edwards Lifesciences, Irvine, USA). Patients with cardiac index (CI) values <2.5 L/min/m² and/or stroke volume index (SVI) <30 mL/beat/m² are considered eligible for the study. Enrolled participants will undergo an echocardiographic examination using the Vivid S6 ultrasound machine (General Electric, Northville, Michigan) and a 3.6 MHz cardiology probe through which the apical projections of chambers 2, 3 and 4 will be acquired; this is necessary to calculate the global longitudinal strain (GLS) using EchoPAC* Clinical Workstation Software (General Electric). A dobutamine infusion will be started in these patients; 24 hours later CI and SVI will be recalculated using EV1000/VolumeView and then a levosimendan infusion will begin for 24 hours. Once the infusion cycle of the calcium-sensitising drug has been carried out, the infusion of dobutamine will be reduced until it stops, and the CI, SVI, GLS and arterial elastance (Ea):Ventricular Elastance (Ees) will be re-evaluated. The primary endpoint is recovery of GLS ≥15% and the secondary endpoint is a relative reduction in mortality of 15%.

ETHICS AND DISSEMINATION

The investigators declare that the study will be conducted in full compliance with international regulations (EU Directive 2016/679/EC) and national implementation (DM 15 July 1997; 211/2003; 200/2007) regarding the clinical trial and the principles of the Declaration of Helsinki. Study results will be disseminated through peer-reviewed journals and conferences. Ethical approval for this study has been given by Comitato Etico Regione Toscana - Area Vasta Centro, Florence, Italy (ethical committee number: 13875_oss) on 25 May 2019 (Chairperson Professor Marco Marchi).

TRIAL REGISTRATION NUMBER

NCT04141410.

Pharmaceutical Treatment for Heart Failure

Heart failure (HF) is defined as a clinical syndrome resulting from structural or functional impairment of ventricular fillings or ejections of blood. Currently, HF is divided into three groups which include HF with reduced ejection fraction (HFrEF), HF with preserved ejection fraction (HFpEF) and HF with midrange EF (HFmrEF). Even though major advances have been made in treating HFrEF during the past decades, heart failure is a fatal disease. In this review, we briefly summarize the current advances in pharmaceutical managements for heart failure, which includes drugs used in acute heart failure as well as those that prevent heart failure progression, in each category major clinical trials are also described. In addition, information about some of potential new drugs are also mentioned. Traditional Chinese medicine also shows its potential in treating HF, and we are still lack of medicine to treat HFpEF.

Repetitive infusion of levosimendan in patients with chronic heart failure: a meta-analysis

Background

Repetitive or intermittent levosimendan infusion is gradually becoming more commonly considered for patients with advanced chronic heart failure. However, previous randomized controlled studies (RCTs) reported conflicting results on the effects of levosimendan when administered repetitively. The aim of this meta-analysis was to generate up-to-date evidence to assess the effect of levosimendan in this group of patients.

Material/Methods

A literature review identified 8 qualified studies. A meta-analysis was performed to assess mortality and left ventricular ejection fraction (LVEF).

Results

Use of levosimendan contributed to significantly reduced mortality at the end of mid-term follow-up. The mortality rates in levosimendan and control group were 23 of 226 (10.2%) and 53 of 198 (26.8%), respectively (RR: 0.40, 95%CI: 0.26–0.63, P<0.0001). The trend of significantly decreased mortality was observed in levosimendan vs. placebo subgroup (RR: 0.28, 95%CI: 0.15–0.54, P=0.0001, I²=0%) but not in levosimendan vs. dobutamine, PGE1, or furosemide subgroup (p=0.19, p=0.64 and p=0.25, respectively). Levosimendan also contributed to significantly improved LVEF improvement at the end of follow-up (mean difference: 3.69%, 95CI: 0.92–6.45%, p=0.009).

Conclusions

Intermittent or repetitive levosimendan infusion might be a promising strategy to reduce mortality and improve LVEF in patients with advanced chronic, but not necessarily acutely decompensated, heart failure to maintain disease stability.

Levosimendan attenuates multiple organ injury and improves survival in peritonitis-induced septic shock: studies in a rat model

INTRODUCTION

The aim of this study was to investigate the effects of levosimendan on rodent septic shock induced by cecal ligation and puncture (CLP).

METHODS

Three hours after peritonitis-induced sepsis, male Wistar rats were randomly assigned to receive an intravenous infusion of levosimendan (1.2 μg/kg/min for 10 min and then 0.3 μg/kg/min for 6 h) or an equivalent volume of saline and vehicle (5% dextrose) solution.

RESULTS

The levosimendan-treated CLP animals had significantly higher arterial pressure and lower biochemical indices of liver and kidney dysfunction compared to the CLP animals (P < 0.05). Plasma interleukin-1β, nitric oxide and organ superoxide levels in the levosimendan-treated CLP group were less than those in CLP rats treated with vehicle (P < 0.05). In addition, the inducible nitric oxide synthase (iNOS) in lung and caspase-3 expressions in spleen were significantly lower in the levosimendan-treated CLP group (P < 0.05). The administration of CLP rats with levosimendan was associated with significantly higher survival (61.9% vs. 40% at 18 h after CLP, P < 0.05). At postmortem examination, the histological changes and neutrophil filtration index in liver and lung were significantly attenuated in the levosimendan-treated CLP group (vs. CLP group, P < 0.05).

CONCLUSIONS

In this clinically relevant model of septic shock induced by fecal peritonitis, the administration of levosimendan had beneficial effects on haemodynamic variables, liver and kidney dysfunction, and metabolic acidosis. (1) Lower levels of interleukin-1β, nitric oxide and superoxide, (2) attenuation of iNOS and caspase-3 expressions, and (3) decreases of neutrophil infiltration by levosimendan in peritonitis-induced sepsis animals suggest that anti-inflammation and anti-apoptosis effects of levosimendan contribute to prolonged survival.

Effectiveness of prophylactic levosimendan in high-risk valve surgery patients

Background

Levosimendan has anti-ischaemic effects, improves myocardial contractility and increases systemic, pulmonary and coronary vasodilatation. These properties suggest potential advantages in high-risk cardiac valve surgery patients where cardioprotection would be valuable. The present study investigated the peri-operative haemodynamic effects of prophylactic levosimendan infusion in cardiac valve surgery patients with low ejection fraction and/or severe pulmonary arterial hypertension.

Methods

Between May 2006 and July 2007, 20 consecutive patients with severe pulmonary arterial hypertension (systolic pulmonary artery pressure ≥ 60 mmHg) and/or low ejection fraction (< 50%) who underwent valve surgery in our clinic were included in the study and randomised into two groups. Levosimendan was administered to 10 patients in group I and not to the 10 patients in the control group. Cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (MPAP) were recorded for each patient preoperatively and for 24 hours following the operation.

Results

CO and CI values were higher in the levosimendan group during the study period (p < 0.05). MPAP and PVR values were significantly lower in the levosimendan group for the 24-hour period (p < 0.05) and SVR values were significantly lower after 24 hours in both groups. When clinical results were considered, no difference in favour of levosimendan was detected regarding the mortality and morbidity rates between the groups.

Conclusion

Levosimendan improved the haemodynamics in cardiac valve surgery patients with low ejection fraction and/or severe pulmonary arterial hypertension, and facilitated weaning from cardiopulmonary bypass in such high-risk patients when started as a prophylactic agent.

An efficacy and mechanism evaluation study of Levosimendan for the Prevention of Acute oRgan Dysfunction in Sepsis (LeoPARDS): protocol for a randomized controlled trial

BACKGROUND

Organ dysfunction consequent to infection ('severe sepsis') is the leading cause of admission to an intensive care unit (ICU). In both animal models and early clinical studies the calcium channel sensitizer levosimendan has been demonstrated to have potentially beneficial effects on organ function. The aims of the Levosimendan for the Prevention of Acute oRgan Dysfunction in Sepsis (LeoPARDS) trial are to identify whether a 24-hour infusion of levosimendan will improve organ dysfunction in adults who have septic shock and to establish the safety profile of levosimendan in this group of patients.

METHODS/DESIGN

This is a multicenter, randomized, double-blind, parallel group, placebo-controlled trial. Adults fulfilling the criteria for systemic inflammatory response syndrome due to infection, and requiring vasopressor therapy, will be eligible for inclusion in the trial. Within 24 hours of meeting these inclusion criteria, patients will be randomized in a 1:1 ratio stratified by the ICU to receive either levosimendan (0.05 to 0.2 μg.kg⁻¹.min⁻¹ or placebo for 24 hours in addition to standard care. The primary outcome measure is the mean Sequential Organ Failure Assessment (SOFA) score while in the ICU. Secondary outcomes include: central venous oxygen saturations and cardiac output; incidence and severity of renal failure using the Acute Kidney Injury Network criteria; duration of renal replacement therapy; serum bilirubin; time to liberation from mechanical ventilation; 28-day, hospital, 3 and 6 month survival; ICU and hospital length-of-stay; and days free from catecholamine therapy. Blood and urine samples will be collected on the day of inclusion, at 24 hours, and on days 4 and 6 post-inclusion for investigation of the mechanisms by which levosimendan might improve organ function. Eighty patients will have additional blood samples taken to measure levels of levosimendan and its active metabolites OR-1896 and OR-1855. A total of 516 patients will be recruited from approximately 25 ICUs in the United Kingdom.

DISCUSSION

This trial will test the efficacy of levosimendan to reduce acute organ dysfunction in adult patients who have septic shock and evaluate its biological mechanisms of action.

TRIAL REGISTRATION

Current controlled trials ISRCTN12776039 (19 September 2013).

Inotropes

Inotropes have been fundamental to resuscitation of acute cardiogenic shock for decades. Heart failure and cardiogenic shock, in severe cases, are syndromes characterized in many patients by a reduction in myocardial contractile force. While inotropes successfully increase cardiac output, their use has been plagued by excessive mortality due to increased tachycardia and myocardial oxygen consumption leading to arrhythmia and myocardial ischemia. There is a pressing need for new inotropic agents that avoid these harmful effects. This review describes the mechanism of action and the clinical utility of some of the older inotropic agents, which are still commonly used, and provides an update for physicians on the development of newer inotropic drugs. The field is rapidly changing, and it is likely that new agents will be designed that improve systolic performance without necessarily increasing the myocardial oxygen consumption.

[Anesthesia for coronary revascularization in patients with Kawasaki disease: case report]

Kawasaki disease is a self-limited vasculitis that occurs predominantly in infants and young children, that is characterized by coronary artery lesions (especially aneurysms). It is one of the leading causes of acquired heart disease in children. The etiology of Kawasaki disease still remains unknown. A hypothesis is that an infectious agent produces clinically apparent disease only in certain genetically predisposed individuals. It also is possible that the disease results from an immunologic response and is triggered by different microbial agents. For unknown reason it dominates in Asians. Treatment is directed to prevent coronary thrombosis and reduce inflammation; it is based on high-dose intravenous immunoglobulin and acetyl salicylic acid, which significantly reduce the risk of coronary artery aneurysms from 25 to 4%. In order to reduce myocardial ischemia, percutaneous coronary interventions and coronary artery bypass graft can be used. There is a lot of information about surgical techniques for coronary artery complications linked to Kawasaki disease, but minimal information about anesthetic techniques; for this reason, we describe the anesthetic management of a patient who required coronary artery bypass graft, and we present a literature review on the topic.

Tolvaptan for the treatment of hyponatremia secondary to the syndrome of inappropriate antidiuretic hormone secretion

Hyponatremia is prevalent in hospitalized patients and predicts a poor prognosis. The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is perceived as one of the most frequent causes of hyponatremia. Traditionally, chronic hyponatremia has been treated with fluid restriction and demeclocycline. However, these treatment options have been unsatisfactory due to problems with treatment compliance and/or safety concerns. In recent years, several vasopressin-receptor antagonists, the vaptans, were introduced into clinical practice. One of these vaptans - tolvaptan - is an oral vasopressin V2-receptor antagonist that induces free water excretion without increasing sodium excretion. Few studies have assessed the role of vaptans in treating hyponatremia in a population with only SIADH. Current data shows that vaptans may safely correct mild or moderate hyponatremia in patients with SIADH. However, further clinical trials are needed to determine the optimal dosing, proper monitoring and adequate precautions for the use of vaptans in this patient population.

Pharmaceutical management of decompensated heart failure syndrome in children: current state of the art and a new approach

Prompt initiation of appropriate and intensive treatment in children with decompensated heart failure is crucial to avoid irreversible end-organ dysfunction. Initial management of these children includes transfer to the pediatric cardiac intensive care unit, basic hemodynamic monitoring, and establishment of intravenous access. Inotropic support should be instituted peripherally before obtaining central venous and arterial access. The team should be prepared for emergent intubation and initiation of mechanical circulatory support. Two experienced physicians should work together to obtain vascular access and manage sedation, airway control, and cardiovascular support. Acute heart failure syndrome in children may be related to cardiomyopathy, myocarditis, congenital heart disease, and acute rejection post heart transplantation. Each of these causes requires a different approach. Fulminant myocarditis may lead to severe morbidity and requires intensive support, although its outcome is considered to be good. Acute heart failure related to newly diagnosed dilated cardiomyopathy may represent end-stage heart failure; therefore, long-term mechanical circulatory support and heart transplantation may be considered to avoid other end-organ dysfunction. Hypertrophic cardiomyopathy may lead to acute decompensation due to 1) left ventricular outflow obstruction, 2) restrictive physiology leading to pulmonary hypertension, or 3) myocardial ischemia associated with coronary artery bridging. Decompensated heart failure associated with congenital heart disease usually represents end-stage heart failure and requires thorough evaluation for heart transplantation. Children with single-ventricle physiology who develop decompensated heart failure after a Fontan procedure are not candidates for mechanical circulatory support and therefore may not survive to heart transplantation. Acute heart failure due to posttransplantation acute rejection requires aggressive antirejection treatment, which places these patients at significant risk for overwhelming opportunistic infections. In our opinion, mechanical circulatory support should be initiated early in children who present with end-stage heart failure associated with hemodynamic instability to avoid end-organ damage.

Comparison of ischemic side effects of levosimendan and dobutamine with integrated backscatter analysis

BACKGROUND

Levosimendan improves cardiac contractility without increasing oxygen consumption. However, its effects on ischemia were not supported with the utilization of a noninvasive parameter of myocardial characterization.

HYPOTHESIS

The changes observed in integrated backscatter (IBS) may be reflective of change in myocardial ischemia. In this study, the effect of levosimendan on ischemia detected by IBS was evaluated in patients with ischemic heart failure (HF).

METHODS

Patients who had LVEF < 40% and NYHA III-IV symptoms of HF were included in this study. Patients were randomized to levosimendan (n = 21), or to dobutamine (n = 25) groups. The cyclic variation of integrated backscatter (CVIBS) was determined as the difference between the maximal and minimal values in a cardiac cycle, average of three consecutive beats. CVIBS was taken from the mid-anteroseptal, mid-inferior, and mid-posterolateral areas of the parasternal short axis images before the drug administration and at the end of the 24-hour infusion period.

RESULTS

Baseline characteristics and concomitant medications were similar in both groups. A significant reduction in CVIBS was detected in anteroseptal (7.6 +/- 1.4 dB versus 5.9 +/- 0.8 dB, p = 0.01), inferior wall (7.4 +/- 0.8 dB versus 6.7 +/- 1.5 dB, p = 0.03), and posterolateral wall (9.0 +/- 1.2 dB versus 8.2 +/- 0.6 dB, p = 0.04) after dobutamine administration, while no significant changes were observed in the levosimendan group in all walls.

CONCLUSIONS

Unlike dobutamine, levosimendan may not induce myocardial ischemia as shown by CVIBS at commonly used dosages in the setting of decompensated HF without active ischemia.

Effects of levosimendan on left atrial functions in patients with ischemic heart failure

BACKGROUND

With further progression of left ventricular (LV) dysfunction, the left atrial (LA) contribution to LV filling gradually decreases, and LA dysfunction deteriorates the decreased LV filling in patients with heart failure (HF).

HYPOTHESIS

This study sought to investigate the effects of levosimendan on LA function in patients with HF.

METHODS

A total of 60 patients having acute decompensated HF with ischemic cardiomyopathy and LV ejection fraction (LVEF) < 40% were included in the study. Patients were randomized to levosimendan (n = 30) or to dobutamine (n = 30). Before and 24 h after treatment, LVEF, mitral inflow peak E and A wave velocity, E/A ratio, mitral lateral annulus peak Em wave velocity, E/Em ratio, LA volumes, and from the LA volumes the active emptying fraction (AEF), passive emptying fraction (PEF), and reservoir fraction (RF) were measured.

RESULTS

All LA volumes were significantly reduced after levosimendan administration, but in the dobutamine group only minimal volume (Vmin) was reduced. Although AEF increased in both groups, the improvement of AEF was greater in the levosimendan group than in the dobutamine group (14% +/- 9% versus 2% +/- 1%, p = 0.001). The PEF (12% +/- 8% versus 21% +/- 6%, p = 0.04) and RF (23% +/- 4% versus 38% +/- 3%, p = 0.001) significantly increased after levosimendan administration, whereas these parameters did not change after dobutamine. In patients receiving levosimendan, there was a significant, positive correlation between PEF and Em (r = 0.475, p = 0.008), and there were significant negative correlations between PEF and E/Em (r = - 0.491, p = 0.006), and AEF and E/Em (r = - 0.654, p = 0.001).

CONCLUSIONS

Left atrial functions respond better to levosimendan than to dobutamine in decompensated HF.

Levosimendan and Calcium Sensitization of the Contractile Proteins in Cardiac Muscle: Impact on Heart Failure

Levosimendan increases the sensitivity of the cardiac fibrils to calcium, favorably affects hemodynamics in patients with heart failure. It is a positive inotrope and a peripheral vasodilator. The elimination half-life of the compound is about 1 hour. The drug decreases pulmonary capillary wedge pressure, increases cardiac output with the improvement in left ventricular ejection fraction leading to symptomatic improvement which includes decreased dyspnea and fatigue. Levosimendan can be used safely with diuretics, nitrates, beta-blockers, digoxin, and angiotensin-converting enzyme inhibitors. The most common adverse effects of levosimendan are headache and hypotension. Prolongation of the QTc interval does not appear to increase the incidence of arrhythmias, including ventricular tachycardia, ventricular fibrillation, and torsades de pointes. Levosimendan is a novel agent in the treatment of decompensated heart failure, representing a newer class of medications aimed at increasing calcium sensitivity. Its properties holds promise for the treatment of heart failure but further large-scale studies will be needed to determine its precise efficacy, safety, as well as the compound's long-term impact on mortality.

Effect of levosimendan on right ventricular systolic and diastolic functions in patients with ischaemic heart failure

OBJECTIVES

Levosimendan is a novel positive inotropic calcium sensitiser agent used in acute left heart failure. In this study, the effect of levosimendan on the right ventricular systolic and diastolic functions was evaluated by tissue Doppler comparing them with dobutamine in patients with ischaemic heart failure.

METHODS

Patients having an acute decompensated heart failure with ischaemic cardiomyopathy and left ventricular ejection fraction <40% were included in the study. Before and 24-h after treatment, peak systolic (Sa), peak early (Ea), peak late (Aa) diastolic annular velocities and Ea/Aa ratio from tricuspid lateral annulus by tissue Doppler and systolic pulmonary artery pressure (SPAP) were measured.

RESULTS

Sa, Ea and the Ea/Aa ratio were significantly increased in the levosimendan group whereas SPAP was significantly reduced. In the dobutamine group, no significant differences were observed in the Sa, Ea, Aa and Ea/Aa ratio in spite of a significant reduction in SPAP. Decrease in SPAP was greater in the levosimendan group (p=0.002).

CONCLUSION

Levosimendan improves right ventricular systolic and diastolic functions.

Tolvaptan, an orally active vasopressin V(2)-receptor antagonist - pharmacology and clinical trials

Tolvaptan is an orally effective nonpeptide arginine vasopressin (AVP) V(2)-receptor antagonist synthesized by Otsuka Pharmaceutical Co., Ltd. In in vitro receptor-binding studies, tolvaptan blocked the binding of [(3)H]AVP to human V(2) receptors with 29-fold greater selectivity than that for V(1a) receptors, and showed no inhibition of V(1b) receptors. Tolvaptan inhibited not only the binding of [(3)H]AVP but also the AVP-induced production of cyclic AMP in human V(2)-receptor-expressing HeLa cells. In addition, tolvaptan has no intrinsic V(2) receptor agonistic effect. In in vivo studies, tolvaptan showed marked aquaresis in healthy and diseased animals. In rat models with acute and chronic hyponatremia, tolvaptan improved hyponatremia, resulting in the prevention of death, and improved organ water retention. Tolvaptan reduced cardiac preload without unfavorable effects on renal functions, systemic hemodynamics, or circulating neurohormones in dogs with heart failure (HF). Furthermore, in animal models of human polycystic kidney disease (PKD), tolvaptan showed a decrease in kidney weight as well as in cyst and fibrosis volume. In clinical trials including the "ACTIV in CHF" study, tolvaptan in addition to standard therapy increased fluid loss resulting in decreased body weight, and improved edema and serum sodium without affecting blood pressure, heart rate, or renal functions in patients with HF. In patients with hyponatremia, treatment with tolvaptan without fluid restriction appeared to be more effective than fluid restriction alone at correcting hyponatremia without an increase in adverse events. A phase III trial EVEREST is currently being conducted to evaluate the long-term efficacy and safety of tolvaptan in hospitalized patients with severe HF. In conclusion, tolvaptan offers the possibility of a useful therapy in hyponatremia, congestive heart failure, and various other diseases that are associated with volume overload. Furthermore, tolvaptan is also expected to be effective in the treatment of PKD.

Hyponatremia: current treatment strategies and the role of vasopressin antagonists

OBJECTIVE

Hyponatremia is a complex electrolyte disorder that results mainly from dysregulation of arginine vasopressin (AVP) by osmotic and nonosmotic mechanisms. Several populations, including the elderly, are at risk for the development of hyponatremia, and awareness of such risk factors can lead to an overall improvement in patient care. AVP receptor antagonists are promising new therapeutic options whose safety and efficacy have been clinically established for some forms of hyponatremia.

DATA SOURCES

A search of MEDLINE (1967-March 2007) was conducted, using the search terms aquaporins, AVP, AVP receptor antagonists, conivaptan, hyponatremia, lixivaptan, and tolvaptan. Additionally, data were obtained from manufacturers' prescribing information.

STUDY SELECTION AND DATA EXTRACTION

All articles identified from the reference search and data sources were evaluated. Material was included in this review if it was relevant to the pathophysiology and management of euvolemic and hypervolemic hyponatremia in hospitalized patients.

DATA SYNTHESIS

A large percentage of hospitalized patients are found to have symptomatic or asymptomatic hyponatremia. One study reported that 24.5% of intensive care patients admitted over a 3 month period experienced hyponatremia at some time during their hospitalization. Conventional management techniques include water restriction, demeclocycline, lithium, and urea, which have demonstrated variable efficacy and toxicity. AVP receptor antagonists, whose safety and efficacy have been established in clinical trials, are providing new therapeutic options.

CONCLUSIONS

AVP receptor antagonists appear to be safe and effective for the treatment of patients with hyponatremia. With conivaptan recently approved by the Food and Drug Administration for use in treating euvolemic and hypervolemic hyponatremia in hospitalized patients and lixivaptan and tolvaptan in the late stages of development, prudent use of these agents requires a thorough understanding of the clinical manifestations of hyponatremia to optimize therapeutic outcomes.

Arrhythmogenic Ion-Channel Remodeling in the Heart: Heart Failure, Myocardial Infarction, and Atrial Fibrillation

Rhythmic and effective cardiac contraction depends on appropriately timed generation and spread of cardiac electrical activity. The basic cellular unit of such activity is the action potential, which is shaped by specialized proteins (channels and transporters) that control the movement of ions across cardiac cell membranes in a highly regulated fashion. Cardiac disease modifies the operation of ion channels and transporters in a way that promotes the occurrence of cardiac rhythm disturbances, a process called “arrhythmogenic remodeling.” Arrhythmogenic remodeling involves alterations in ion channel and transporter expression, regulation and association with important protein partners, and has important pathophysiological implications that contribute in major ways to cardiac morbidity and mortality. We review the changes in ion channel and transporter properties associated with three important clinical and experimental paradigms: congestive heart failure, myocardial infarction, and atrial fibrillation. We pay particular attention to K+, Na+, and Ca2+channels; Ca2+transporters; connexins; and hyperpolarization-activated nonselective cation channels and discuss the mechanisms through which changes in ion handling processes lead to cardiac arrhythmias. We highlight areas of future investigation, as well as important opportunities for improved therapeutic approaches that are being opened by an improved understanding of the mechanisms of arrhythmogenic remodeling.

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.

Effect of levosimendan on E/E' ratio in patients with ischemic heart failure

BACKGROUND

Levosimendan is a novel positive inotropic calcium sensitizer agent used in acute heart failure. In acute heart failure, it improves hemodynamic parameters more favorably than the conventional positive inotropes. In this study, the effect levosimendan on E/E' ratio as a non-invasive indicator of LV filling pressure was evaluated compared to dobutamine in a prospective, randomized, patient-blind manner.

METHODS

Patients with an LVEF < 40% admitting with acute heart failure attack with ischemic origin were included to this study. Patients were randomized to levosimendan (n=30, mean age: 64+/-10 years, 63% male) or dobutamine (n=32, mean age: 66+/-8 years, 54% male) groups. The ratio of the peak E wave velocity taken from mitral inflow with PW Doppler to the peak E' wave velocity taken from mitral lateral annulus with tissue Doppler was determined. Pre-treatment and 24-hour after the treatment E/E' ratios were calculated and then compared in both groups.

RESULTS

Age, gender, concomitant medications were similar in both groups (p>0.05). There was no difference for pre-treatment baseline E/E' ratios between levosimendan and dobutamine groups (15.7+/-4.0 vs 15.2+/-7.5 respectively, p=0.1). There were significant reductions in post-treatment E/E' ratios in levosimendan (15.7+/-4.0 vs 9.3+/-2.8, p=0.01) and dobutamine groups (15.2+/-7.5 vs 12.9+/-5.6, p=0.04). However, the reduction in levosimendan group was greater compared to dobutamine group (p=0.01).

CONCLUSIONS

Levosimendan causes a greater reduction of E/E' ratio compared to dobutamine in acute systolic left heart failure. This may explain the more favorable hemodynamic effects of levosimendan when compared to conventional positive inotropics in patients with systolic left heart failure.

Coronary Artery Bypass for Heart Failure in Ischemic Cardiomyopathy: 17-Year Follow-Up

BACKGROUND

Coronary artery bypass grafting (CABG) has been safely extended to ischemic cardiomyopathy and heart failure, but outcome beyond 5 years remains poorly defined.

METHODS

We retrospectively analyzed 45 consecutive angina-free patients with ischemic left ventricular dysfunction (ejection fraction < or = 0.35) and heart failure (New York Heart Association functional class III to IV) who were selected for CABG between 1988 and 1995. Positron emission tomography was used for preoperative identification of myocardial viability.

RESULTS

The 30-day mortality was 4.4%. At a median follow-up of 117 months (longest observation, 205 months), the probability of survival at 1, 5, 10, and 15 years after CABG was 93.3%, 84%, 65%, and 44%, respectively. At multivariable analysis, a left ventricular end-diastolic pressure (LVEDP) of 25 mm Hg or more predicted a threefold increase of the hazard of death (p = 0.02), whereas a LVEDP of 20 mm Hg or more correlated with the requirement of an intraaortic balloon pump perioperatively (p = 0.04). Other independent predictors of survival were age older than 70 years and peripheral vascular disease. Cardiac events accounted for 88% of late deaths, which were primarily related to sudden death or progressive heart failure. Most patients were in New York Heart Association functional class I to II at late follow-up.

CONCLUSIONS

CABG alone yields good long-term outcome in selected angina-free patients with ischemic systolic dysfunction and advanced heart failure. However, associated diastolic impairment, reflected by elevated LVEDP, predicts reduced long-term survival despite myocardial viability.

New agents for managing hyponatremia in hospitalized patients

PURPOSE

An overview of hyponatremia is provided, including its pathophysiology, clinical manifestations, signs and symptoms, and treatment, particularly with arginine vasopressin (AVP)-receptor antagonists.

SUMMARY

Hyponatremia (generally defined as a serum sodium concentration of <135 meq/L) is one of the most common electrolyte disorders in hospitalized and clinic patients. It may be caused by a number of conditions, including infections, heart disease, surgery, malignancy, and medication use. Clinical signs and symptoms such as hallucinations, lethargy, weakness, bradycardia, respiratory depression, seizures, coma, and death have been reported. Conventional treatment consists of fluid restriction and administration of hypertonic saline and pharmacologic agents, such as demeclocycline, lithium carbonate, and urea. These treatment options are often of limited effectiveness or difficult for patients to tolerate. AVP promotes the reabsorption of water in the renal collecting ducts by activation of V(2) receptors, resulting in water retention and dilution of serum solutes. The AVP-receptor antagonists, conivaptan, lixivaptan, and tolvaptan, are being studied for the treatment of hyponatremia. Conivaptan has been shown in clinical trials to increase free-water excretion and safely normalize serum sodium concentrations in patients with hyponatremia and is well tolerated. Also in clinical trials, lixivaptan and tolvaptan have safely improved serum sodium concentrations in patients with hyponatremia.

CONCLUSION

Hyponatremia is a serious health condition for which treatment should be carefully performed. As new agents for treating hyponatremia, AVP-receptor antagonists have demonstrated efficacy and safety in clinical trials and may serve as significant improvements in the current treatment options for managing this disorder.

Review of current and investigational pharmacologic agents for acute heart failure syndromes

Acute heart failure syndromes (AHFS) are a major public health problem and present a therapeutic challenge to clinicians. Commonly used agents in the treatment of AHFS include diuretics, vasodilators (eg, nitroglycerin, nitroprusside, nesiritide), and inotropes (eg, dobutamine, dopamine, milrinone). Patients admitted to hospital with AHFS and low cardiac output state (AHFS/LO) represent a subgroup with very high inhospital and postdischarge mortality rates. Most of these patients require intravenous inotropic therapy. However, the use of current intravenous inotropes has been associated with risk for hypotension, atrial and ventricular arrhythmias, and possibly increased postdischarge mortality, particularly in those with coronary artery disease. Consequently, there is an unmet need for new agents to safely improve cardiac performance (contractility and/or active relaxation) in this patient population. This article reviews a selection of current and investigational agents for the treatment of AHFS, with a main focus on the high-risk patient population with AHFS/LO.

Tolvaptan for the treatment of hyponatremia and congestive heart failure

Tolvaptan is an oral, once-daily nonpeptide arginine vasopressin V2-receptor antagonist under development for the treatment of hyponatremia and congestive heart failure. In Phase II clinical trials, tolvaptan, in addition to standard therapy, increased fluid loss, resulting in decreased body weight and improved edema and serum sodium without affecting blood pressure, heart rate or renal function in patients with heart failure. The compound appeared to be well tolerated and dose-dependent adverse events were generally realated to its pharmacological activity, such as thirst and dry mouth. In patients with hyponatremia, tolvaptan appears to be more effective than fluid restriction at improving sodium levels without an increase in adverse events. An international Phase III outcome study; Efficacy of Vasopressin antagonism in hEaRt failurE outcome Study with Tolvaptan (EVEREST), evaluating the long-term efficacy and safety of tolvaptan in patients hospitalized with worsening heart failure, is currently ongoing.

Levosimendan Reversing Low Output Syndrome After Heart Transplantation

After heart transplantation primary graft failure is a major cause of early mortality. Treatment options include inotropes and mechanical assist devices. Developing better methods would impact on patients' short- and long-term survival. We present a case of primary graft failure manifested as cardiogenic shock unresponsive to catecholamines and a phosphodiesterase inhibitor. Reversal of low output syndrome was achieved with a new type of inotropic agent, levosimendan, leading to the later complete recovery.

Heart failure therapy in children

The most common reason for heart failure in children is volume overload secondary to a left-to-right shunt. Therefore, an accurate diagnosis with identification of possible surgical or interventional reactions should be the first priority. Medical therapy is mainly based on diuretics, angiotensin-converting enzyme inhibitors, cardiac glycosides and beta-blockers. There are few prospective trials in pediatric cardiology, but the available data reach a similar conclusion to that of adults with heart failure. Diuretics are an important tool in patients with fluid retention, and angiotensin-converting enzyme inhibitors are helpful in patients with volume overload of the ventricles. Cardiac glycosides are still in use, but there is a trend toward primary use of diuretics. Angiotensin-converting enzyme inhibitors and beta-blockers have been used successfully in the treatment of heart failure in children, but there are limited data on its efficacy.

Syndrome of inappropriate antidiuresis

The syndrome of inappropriate antidiuresis is the most common cause of euvolemic hyponatremia and complicates a wide spectrum of diseases and neurosurgical conditions. The syndrome is characterized by clinical euvolemia, dilute plasma osmolality and inappropriately concentrated urine, with normal renal, adrenal and thyroid function. Hyponatremia in syndrome of inappropriate antidiuresis represents an excess of plasma water, rather than sodium deficiency. The severity of hyponatremia is limited by renal escape from antidiuresis. Treatment varies according to symptoms, severity and speed of onset of hyponatremia. Acute, severe, symptomatic hyponatremia may require rapid treatment with hypertonic saline, with care to avoid central pontine myelinosis. Chronic hyponatremia is managed with fluid restriction and demeclocycline for unresponsive cases. Vasopressin antagonists represent a new option for chronic hyponatremia of syndrome of inappropriate antidiuresis.

Randomized clinical trials with levosimendan

There are important unmet needs in the treatment of acute heart failure syndromes (AHFS). The unique dual mechanism of action of levosimendan suggests that this new agent may help fill some of these unmet needs. A review of randomized, controlled clinical trials with levosimendan demonstrated that it is well tolerated, and its use results in significantly reduced pulmonary capillary wedge pressure (PCWP) and increased cardiac output. Effects of levosimendan on PCWP and cardiac output are more pronounced than those observed with dobutamine. Levosimendan treatment is also associated with significantly improved clinical symptoms. Moreover, data from 3 trials indicate that levosimendan treatment was associated with improved 6-month survival compared with dobutamine treatment or placebo. Emerging data suggest that levosimendan is beneficial for patients with acute myocardial ischemia. Thus, early clinical indicators suggest that levosimendan may help prevent myocardial injury during hospitalization for AHFS and may be well suited for first-line therapy for AHFS.

Pathophysiologic targets in the early phase of acute heart failure syndromes

An episode of acute heart failure syndromes (AHFS) can be defined as a rapid or gradual onset of signs and symptoms of heart failure (HF) in hospital admission and can arise from a variety of pathophysiologic mechanisms. This article reviews our current understanding of the pathophysiology of AHFS in order to identify potential therapeutic targets. Most patients with AHFS present with either normal systolic blood pressure or elevated blood pressure. Patients who present with elevated systolic blood pressure usually have pulmonary congestion and a relatively preserved left ventricular ejection fraction (LVEF), and have symptoms that typically develop abruptly, these patients often are elderly women. Patients with normal systolic blood pressure presenting with systemic congestion and reduced LVEF are usually younger, with a history of chronic HF, and have symptoms that develop gradually over days or weeks. Accordingly, most episodes of AHFS can be classified as either "vascular" failure or "cardiac" failure. In addition to the abnormal hemodynamics (increase in pulmonary capillary wedge pressure and/or decrease in cardiac output) that characterize patients with AHFS, myocardial injury--which may be related to a decrease in coronary perfusion and/or further activation of neurohormones and renal dysfunction (ie, the cardiorenal syndrome)--probably contributes to short-term and post-discharge cardiac events. Patients with AHFS also have significant cardiac and non-cardiac underlying conditions that contribute to the pathogenesis of AHFS, including coronary artery disease (ischemia, hibernating myocardium, and endothelial dysfunction), hypertension, atrial fibrillation, and type 2 diabetes mellitus. The goals of therapy for AHFS should be not only to improve symptoms and hemodynamics, but also to preserve or improve renal function and prevent myocardial damage.