Hemodynamic effects of levosimendan added to dobutamine in patients with decompensated advanced heart failure refractory to dobutamine alone

Inotropic Agents: Are We Still in the Middle of Nowhere?

Inotropes are prescribed to enhance myocardial contractility while vasopressors serve to improve vascular tone. Although these medications remain a life-saving therapy in cardiovascular clinical scenarios with hemodynamic impairment, the paucity of evidence on these drugs makes the choice of the most appropriate vasoactive agent challenging. As such, deep knowledge of their pharmacological and hemodynamic effects becomes crucial to optimizing hemodynamic profile while reducing the potential adverse effects. Given this perspective, it is imperative for cardiologists to possess a comprehensive understanding of the underlying mechanisms governing these agents and to discern optimal strategies for their application across diverse clinical contexts. Thus, we briefly review these agents' pharmacological and hemodynamic properties and their reasonable clinical applications in cardiovascular settings. Critical interpretation of available data and the opportunities for future investigations are also highlighted.

Levosimendan Plus Dobutamine in Acute Decompensated Heart Failure Refractory to Dobutamine

Randomized studies showed that Dobutamine and Levosimendan have similar impact on outcome but their combination has never been assessed in acute decompensated heart failure (ADHF) with low cardiac output. This is a retrospective, single-center study that included 89 patients (61 ± 15 years) admitted for ADHF requiring inotropic support. The first group consisted of patients treated with dobutamine alone (n = 42). In the second group, levosimendan was administered on top of dobutamine, when the superior vena cava oxygen saturation (ScVO2) remained <60% after 3 days of dobutamine treatment (n = 47). The primary outcome was the occurrence of major cardiovascular events (MACE) at 6 months, defined as all cause death, heart transplantation or need for mechanical circulatory support. Baseline clinical characteristics were similar in both groups. At day-3, the ScVO2 target (>60%) was reached in 36% and 32% of patients in the dobutamine and dobutamine-levosimendan group, respectively. After adding levosimendan, 72% of the dobutamine-levosimendan-group reached the ScVO2 target value at dobutamine weaning. At six months, 42 (47%) patients experienced MACE (n = 29 for death). MACE was less frequent in the dobutamine-levosimendan (32%) than in the dobutamine-group (64%, p = 0.003). Independent variables associated with outcome were admission systolic blood pressure and dobutamine-levosimendan strategy (OR = 0.44 (0.23–0.84), p = 0.01). In conclusion, levosimendan added to dobutamine may improve the outcome of ADHF refractory to dobutamine alone.

Shock Management for Cardio-surgical Intensive Care Unit Patient: The Silver Days

Shock in cardio-surgical intensive care unit (ICU) patients requires prompt identification of the underlying condition and timely therapeutic interventions. Management during the first 6 hours, also referred to as "the golden hours", is of paramount importance to reverse the shock state and improve the patient's outcome. The authors have previously described a state-of-the-art diagnostic work-up and discussed how to optimise preload, vascular tone, contractility, heart rate and oxygen delivery during this phase. Ideally, shock can be reversed during this initial period. However, some patients might have developed multiple organ dysfunction, which persists beyond the first 6 hours despite the early haemodynamic treatment goals having been accomplished. This period, also referred to as "the silver days", is the focus of this review. The authors discuss how to reduce vasopressor load and how to minimise adrenergic stress by using alternative inotropes, extracorporeal life-support and short acting beta-blockers. The review incorporates data on fluid weaning, safe ventilation, daily interruption of sedation, delirium management and early rehabilitation. It includes practical recommendations in areas where the evidence is scarce or controversial. Although the focus is on cardio-surgery ICU patients, most of the considerations apply to critical ill patients in general.

Diagnosis and management of acute heart failure

Acute heart failure (AHF) is a life threatening clinical syndrome with a progressively increasing incidence in general population. Turkey is a country with a high cardiovascular mortality and recent national statistics show that the population structure has turned to an 'aged' population.As a consequence, AHF has become one of the main reasons of admission to cardiology clinics. This consensus report summarizes clinical and prognostic classification of AHF, its worldwide and national epidemiology, diagnostic work-up, principles of approach in emergency department,intensive care unit and ward, treatment in different clinical scenarios and approach in special conditions and how to plan hospital discharge.

Levosimendan in critical illness: a literature review

Levosimendan, the active enantiomer of simendan, is a calcium sensitizer developed for treatment of decompensated heart failure, exerts its effects independently of the beta adrenergic receptor and seems beneficial in cases of severe, intractable heart failure. Levosimendan is usually administered as 24-h infusion, with or without a loading dose, but dosing needs adjustment in patients with severe liver or renal dysfunction. Despite several promising reports, the role of levosimendan in critical illness has not been thoroughly evaluated. Available evidence suggests that levosimendan is a safe treatment option in critically ill patients and may reduce mortality from cardiac failure. However, data from well-designed randomized controlled trials in critically ill patients are needed to validate or refute these preliminary conclusions. This literature review is an attempt to synthesize available evidence on the role and possible benefits of levosimendan in critically ill patients with severe heart failure.

The effects of levosimendan and dobutamine in experimental bupivacaine-induced cardiotoxicity

Background

Accidental intravenous exposure to bupivacaine is highly cardiotoxic and may lead to death. Positive inotropic agents are usually utilized in resuscitative efforts. We have compared the efficacy of levosimendan, a novel inotropic agent, with dobutamine and their combination in a rat model of bupivacaine intoxication.

Methods

Twenty-eight male Wistar albino rats weighing between 250-300 g were divided into these four groups: control (C), levosimendan (L), dobutamine (D) and dobutamine+levosimendan (D+L). Bupivacaine was administered at a dose of 3 mg/kg/min until cardiac arrest occurred or for 120 min. ECG, heart rate, blood pressure, arterial blood gases, and end tidal CO₂ levels were monitored. Levosimendan was administered as a bolus of 12 μg/kg for 10 min and continued as an infusion at 0.3 μg/kg/min. Dobutamine was infused at a dose of 3 μg/kg/min. The time required for a 50% and 75% decrease in heart rate and blood pressure with a total time to cardiac arrest and bupivacaine dose for obtaining cardiac arrest were analyzed.

Results

Time periods for heart rate reductions of 50% and 75% were significantly longer in groups L (903, 1198 s), D (984, 1542 s) and L+D (1705, 3152 s) compared with the control group (345, 538 s p < 0.001). Median times to mean blood pressure reductions of 50% and 75% were 399 - 504 s in the control group, 1005 -1204 s in group L, 685 - 1009 s in group D and 1544- 2982 s in group L+D, and the difference was significant compared with the control group. Median time duration to asystole was 703 s in the control group compared with 1385 s in group L, 1789 s in group D and 3557 s in group L+D. Time to cardiac arrest was significantly higher in all 3 study groups. It was also significantly higher in the L+D group compared with both groups L and D separately.

Conclusion

A combination of dobutamine with levosimendan significantly increased survival times in this bupivacaine-induced toxicity rat model compared with the control, levosimendan, and dobutamine groups.

Rotating inotrope therapy in a pediatric population with decompensated heart failure

OBJECTIVE

To describe the clinical course of a group of patients who received a rotating inotrope regimen, including levosimendan, for decompensated congestive heart failure.

DESIGN

Case series.

SETTING

Pediatric intensive care unit in a tertiary care children's hospital.

PATIENTS

Nine pediatric patients with severe, decompensated heart failure.

INTERVENTION

The study patients received a rotating inotrope regimen, including levosimendan, dobutamine, and, in some cases, milrinone.

MEASUREMENTS AND MAIN RESULTS

Six patients were weaned from positive-pressure ventilation. Eight patients were discharged from the intensive care unit, and seven survived to hospital discharge. Two patients were successfully bridged to orthotopic cardiac transplantation. The therapies were generally well tolerated.

CONCLUSIONS

Rotating inotropes were safe and seemed to be effective in this heterogeneous population of infants and children with decompensated heart failure. This therapeutic regimen warrants prospective comparative analysis.

Effects of levosimendan versus dobutamine on left atrial function in decompensated heart failure

BACKGROUND

Although the effects of levosimendan on the left ventricle (LV) have been studied, its effect on left atrial (LA) function is poorly understood, despite its key role in optimizing LV function.

OBJECTIVE

To compare the effects of levosimendan and dobutamine on LA and LV function in patients with decompensated heart failure (DHF).

METHODS

Seventy-four patients (mean [+/- SD] age 64+/-10 years) with DHF and an LV ejection fraction of 35% or lower were randomly assigned to receive levosimendan (n=37) or dobutamine (n=37). LA active emptying fraction, LA passive emptying fraction (PEF) and the ratio of mitral inflow early diastolic velocity to annulus velocity (E/e) were evaluated with pulsed wave and tissue Doppler imaging along with plasma B-type natriuretic peptide (BNP) level measurements before and after drug infusion.

RESULTS

The ejection fraction was significantly increased in both groups. The levosimendan group had a greater decrease in BNP and a greater increase in active emptying fraction at 24 h compared with the dobutamine group. The PEF, E/e and deceleration time of the E wave were significantly improved in the levosimendan group, but not in the dobutamine group. Levosimendan- induced percentage change of BNP was significantly correlated with the percentage change of E/e and PEF (r=0.48 [P<0.005] and r=-0.38 [P<0.05], respectively).

CONCLUSIONS

In patients with DHF, levosimendan and dobutamine both improve LV systolic function. However, levosimendan also improves LV diastolic function and LA performance in parallel with a greater improvement in neurohormonal activation compared with dobutamine.

Inotropic agents improve the peripheral microcirculation of patients with end-stage chronic heart failure

BACKGROUND

Skeletal muscle microcirculation impairment in patients with chronic heart failure (CHF) seems to correlate with disease severity. We evaluated the microcirculation by near-infrared spectroscopy (NIRS) occlusion technique before and after inotropic infusion.

METHODS

We evaluated 25 patients with stable CHF, 30 patients with end-stage CHF (ESCHF) receiving treatment with intermittent infusion of inotropic agents, and 12 healthy subjects. Thenar muscle tissue oxygen saturation (StO(2)%) was measured noninvasively by NIRS before, during, and after 3-minute occlusion of the brachial artery (occlusion technique) in all subjects and in patients with ESCHF before and after 6 hours of inotropic infusion (dobutamine and/or levosimendan) or placebo (N = 5).

RESULTS

Patients with ESCHF or CHF presented significantly lower StO(2)% than healthy subjects (74.5% +/- 7%, 78.6% +/- 6%, and 85% +/- 5%, respectively; P = .0001), lower oxygen consumption rate during occlusion (24.6% +/- 8%/min, 28.6% +/- 10%/min, and 38.1% +/- 11.1%/min, respectively; P = .001), and lower reperfusion rate (327% +/- 141%/min, 410% +/- 106%/min, and 480% +/- 133%/min, respectively; P = .002). After 6 hours of inotropic infusion, patients with ESCHF showed significantly increased StO(2)% (74.5% +/- 7% to 82% +/- 9%, P = .001), oxygen consumption rate (24.6% +/- 8%/min to 29.3% +/- 8%/min, P = .009), and reperfusion rate (327% +/- 141%/min to 467% +/- 151%/min, P = .001). No statistical difference was noted in the placebo group.

CONCLUSION

Peripheral muscle microcirculation as assessed by NIRS is impaired in patients with CHF. This impairment is partially reversed by infusion of inotropic agents in patients with ESCHF.

[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.

A 6-Month Follow-up of Intermittent Levosimendan Administration Effect on Systolic Function, Specific Activity Questionnaire, and Arrhythmia in Advanced Heart Failure

BACKGROUND

Levosimendan (LS) improves cardiac contractility without increasing myocardial oxygen demand. We administrated LS on a monthly intermittent 24-hour protocol and evaluated the clinical effect after 6 months in a randomized, open, prospective study.

METHODS AND RESULTS

Fifty patients (age 45-65 years) with LV systolic dysfunction and New York Heart Association (NYHA) III or IV were randomized in 2 groups. LS group (n = 25) was compared with a control group (n = 25) matched for sex, age, and NYHA class. LS was given monthly on a 24-hour intravenous protocol for 6 months. Patients were evaluated by specific activity questionnaire (SAQ) and echocardiography (ECHO) before and 3 to 5 days after last drug administration, whereas 24-hour Holter recording was performed before and during last drug administration. Patients in LS and control group had same baseline SAQ, ECHO, and Holter parameters. At the end of the study, a larger proportion of patients in the levosimendan group reported improvement in symptoms (dyspnea and fatigue) (65% versus 20% in controls, P < .01). After 6 months, the LS group had a significant increase in LV ejection fraction versus controls (28 +/- 7 versus 21 +/- 4 %, P = .003), LV shortening fraction (15 +/- 3 versus 11 +/- 3 %, P = .006) and a decrease in mitral regurgitation (1.5 +/- 0.8 versus 2.7 +/- 0.6, P = .0001). There was no increase in supraventricular or ventricular beats or supraventricular tachycardia and VT episodes in LS group, compared with controls. Two patients from the LS group died in the 6-month follow-up period, compared with 8 patients in the control group (8% versus 32%, P < .05).

CONCLUSIONS

A 6-month intermittent LS treatment in patients with decompensated advanced heart failure improved symptoms and LV systolic function.

The Effects of Levosimendan in Cardiac Surgery Patients with Poor Left Ventricular Function

BACKGROUND

Patients with poor left ventricular function often require inotropic drug support immediately after cardiopulmonary bypass. Levosimendan improves cardiac function by a novel mechanism of action compared to currently available drugs. We hypothesized that, in patients with severely compromised ventricular function, the use of levosimendan would be associated with better postoperative cardiac function than with inotropic drugs that increase myocardial oxygen consumption.

METHODS

Thirty patients with a preoperative ejection fraction < or =30% scheduled for elective cardiac surgery with cardiopulmonary bypass were randomized to two different inotropic protocols: milrinone 0.5 microg [corrected] x kg(-1) x min(-1) or levosimendan 0.1 microg [corrected] x kg(-1) x min(-1), started immediately after the release of the aortic crossclamp. The treatment was masked to the observers. All patients received dobutamine 5 microg [corrected] x kg(-1) x min(-1).

RESULTS

Stroke volume was similar between groups initially after surgery, but it declined 12 h after surgery in the milrinone group but not in the levosimendan group (P < 0.05 between groups) despite similar filling pressures. Total dose, duration of inotropic drug administration and norepinephrine dose were lower in the levosimendan group than in the milrinone group (P < 0.05). The duration of tracheal intubation was shorter in the former group compared with the milrinone group (P = 0008). Three patients in the milrinone group but none in the levosimendan group died within 30 days of surgery.

CONCLUSION

In cardiac surgery patients with a low preoperative ejection fraction, stroke volume was better maintained with the combination of dobutamine with levosimendan than with the combination of dobutamine with milrinone.

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.

Early experience with Levosimendan in children with ventricular dysfunction

OBJECTIVE

To describe our preliminary experience with Levosimendan, a new calcium-sensitizing agent in critically unwell infants and children with severe heart failure.

DESIGN

Retrospective cohort analysis.

SETTING

Pediatric intensive care unit.

PATIENTS

Fifteen children aged 7 days to 18 yrs (median age 38 months) with severe myocardial dysfunction secondary to end-stage heart failure, or acute heart failure, who were inotrope-dependent (requiring at least one catecholamine).

INTERVENTIONS

A single dose (bolus and intravenous infusion over 24-48 hrs) of Levosimendan was given under continuous hemodynamic monitoring in our intensive care unit. Eleven children received a single dose, three children received two doses, and one child received four doses. Echocardiographic assessments of ventricular function were made before and 3-5 days after Levosimendan infusion.

MEASUREMENTS AND MAIN RESULTS

Heart rate, systolic pressure, diastolic pressure, mean blood pressure, and central venous pressure were unchanged during and after Levosimendan. Levosimendan allowed for discontinuation of catecholamines in ten patients and a dose reduction in three. The dose of dobutamine was reduced from 6.4 microg/kg/min pre-Levosimendan to 1.8 microg/kg/min on day 5 (p < .01). Ejection fraction for the group as a whole improved from 29.8% to 40.5% (p = .015); this did not increase significantly in patients with end-stage heart failure but increased by 63% in the children with acute heart failure.

CONCLUSIONS

Levosimendan can be safely administered to infants and children with severe heart failure. Levosimendan allowed for substantial reduction in catecholamine infusions in children with end-stage or acute heart failure and also produced an objective improvement in myocardial performance in children with acute heart failure.

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.

European experience on the practical use of levosimendan in patients with acute heart failure syndromes

The novel calcium sensitizer and ATP-dependent potassium channel opener levosimendan has been introduced for routine use in several European countries. Recent reports on clinical experience confirm the positive hemodynamic results and beneficial clinical effects described in the initial dose-finding and randomized comparative therapeutic trials in patients with severe low-output heart failure. In addition, studies in small series of patients with cardiogenic shock after myocardial infarction and/or surgical interventions and post-interventional myocardial dysfunction (stunning) indicate that the inotropic and vasodilating actions of levosimendan may be of value in a wider range of indications. Dose recommendations, combination with other drugs, and potential side effects are discussed in this overview.

Efficacy and safety of intermittent, long-term, concomitant dobutamine and levosimendan infusions in severe heart failure refractory to dobutamine alone

Thirty-six consecutive patients in New York Heart Association functional class IV, who were resistant to 24-hour continuous dobutamine infusion, were treated with continuous infusions of dobutamine 10 microg/kg/min for > or =48 hours (group I, n = 18), followed by weekly intermittent 8-hour infusions or more often if needed. In group II (n = 18), after the initial 24-hour infusion of dobutamine, a 24-hour levosimendan infusion was added followed by biweekly 24-hour infusions. The addition of intermittent levosimendan infusions prolonged the survival of patients with advanced heart failure refractory to intermittent dobutamine infusions (45-day survival rates were 6% and 61% in groups I and II, respectively; p = 0.0002, log-rank test).