Levosimendan in critical illness: a literature review

Old and New Drugs for Treatment of Advanced Heart Failure

BACKGROUND

Advanced heart failure (HF) is a progressive disease with high mortality and limited medical therapeutic options. Long-term mechanical circulatory support and heart transplantation remain goldstandard treatments for these patients; however, access to these therapies is limited by the advanced age and multiple comorbidities of affected patients, as well as by the limited number of organs available.

METHODS

Traditional and new drugs available for the treatment of advanced HF have been researched.

RESULTS

To date, the cornerstone for the treatment of patients with advanced HF remains water restriction, intravenous loop diuretic therapy and inotropic support. However, many patients with advanced HF experience loop diuretics resistance and alternative therapeutic strategies to overcome this problem have been developed, including sequential nephron blockade or use of the hypertonic saline solution in combination with high-doses of furosemide. As classic inotropes augment myocardial oxygen consumption, new promising drugs have been introduced, including levosimendan, istaroxime and omecamtiv mecarbil. However, pharmacological agents still remain mainly short-term or palliative options in patients with acute decompensation or excluded from mechanical therapy.

CONCLUSION

Traditional drugs, especially when administered in combination, and new medicaments represent important therapeutic options in advanced HF. However, their impact on prognosis remains unclear. Large trials are necessary to clarify their therapeutic potential and prognostic role in these fragile patients.

Contribution of Levosimendan in Weaning from Mechanical Ventilation in Patients with Left Ventricular Dysfunction: A Pilot Study

Purpose

Mechanically ventilated patients with left ventricular (LV) dysfunction are at risk of weaning failure. We hypothesized that optimization of cardiovascular function might facilitate the weaning process. Therefore, we investigated the efficacy of levosimendan in difficult-to-wean patients with impaired LV performance.

Materials and Methods

Nineteen mechanically ventilated patients, with LV ejection fraction (LVEF) 34 ± 8%, difficult-to-wean from the ventilator, were assessed by transthoracic echocardiography before the start and at the end of a spontaneous breathing trial (SBT) (first SBT). Eight patients successfully weaned. The remaining 11 failed-to-wean patients received a 24-hour infusion of levosimendan, and they were reassessed during a second SBT.

Results

After levosimendan administration, LVEF increased from 30 ± 10 to 36 ± 3% (p=0.01). End-SBT peak e′ velocity increased from 7 to 9 cm/s (p=0.02). E/e′ increased from 10.5 to 12.9 during the first SBT, whereas it remained constant at 10 throughout the second SBT (p=0.01). During the second SBT, partial pressure of arterial oxygen and central venous oxygen saturation improved, compared to the first one (93 ± 34 vs. 67 ± 28 mmHg, p=0.03, and 66 ± 11% vs. 57 ± 9%, p=0.02, respectively). Nine of the 11 patients were successfully weaned from the ventilator.

Conclusions

In difficult-to-wean from mechanical ventilation patients with LV dysfunction, levosimendan might contribute to successful weaning by improving both systolic and diastolic LV function.

Thioimidate Bond Formation between Cardiac Troponin C and Nitrile-containing Compounds

We have investigated the mechanism and reactivity of covalent bond formation between cysteine-84 of the regulatory domain of cardiac troponin C and compounds containing a nitrile moiety similar to the calcium sensitizer levosimendan. The results of modifications to the levosimendan framework ranged from a large increase in covalent bond formation to complete inactivity. We present the biological activity of one of the most potent compounds. Limitations, including compound solubility and degradation at acidic pH, have prevented thorough investigation of the potential of these compounds. Our studies reveal the efficacious nature of the malononitrile moiety in targeting cNTnC and its potential in future cardiotonic drug design.

A contemporary review of peripartum cardiomyopathy

Peripartum cardiomyopathy reflects the presence of cardiac failure in the absence of determinable heart disease and occurs in late third trimester of pregnancy or up to 6 months postpartum. A full understanding of pathophysiological mechanisms is lacking, but excess prolactin levels, haemodynamic alterations, inflammation and nutritional deficiencies have all been implicated. Its clinical presentation has distinct overlap with physiological alterations in healthy pregnancy and this presents a diagnostic challenge. However, echocardiography can provide significant benefit in accurate assessment and narrowing of differentials. Pharmacotherapy is broadly aligned with established guidelines for cardiac failure, but specific therapies are indicated for treatment of clinical sequelae. Moreover, an individualistic approach is required based on clinical context to manage delivery. Further research appears imperative to optimise management strategies and reduce disease burden.

Levosimendan Versus Dobutamine in Myocardial Injury Patients with Septic Shock: A Randomized Controlled Trial

BACKGROUND We aimed to investigate the effect of levosimendan on biomarkers of myocardial injury and systemic hemodynamics in patients with septic shock. MATERIAL AND METHODS After achieving normovolemia and a mean arterial pressure of at least 65 mmHg, 38 septic shock patients with low cardiac output (left ventricular ejective fraction), LEVF £45%) were randomly divided into two groups: levosimendan dobutamine. Patients in the levosimendan and dobutamine groups were maintained with intravenous infusion of levosimendan (0.2 μg/kg/minute) and dobutamine (5 μg/kg/minute) for 24 hours respectively. During treatment we monitored hemodynamics and LVEF, and measured levels of heart-type fatty acid binding protein (HFABP), troponin I (TNI), and brain natriuretic peptide(BNP). In addition, the length of mechanical ventilation, intensive care unit (ICU) stay, hospital stay, and 28-day mortality were compared between the two groups. RESULTS The levosimendan group and the dobutamine group were well matched with respect to age (years, 55.4 ± 1 7.5 versus 50.2 ± 13.6) and gender (males, 68.4% versus 57.9%). Levosimendan-treated patients had higher stroke volume index (SVI), cardiac index (CI), LVEF, and left ventricular stroke work index (LVSWI), and lower extravascular lung water index (EVLWI) compared to dobutamine-treated patients (p<0.05). HFABP, TNI, and BNP in the levosimendan group were less than in the dobutamine group (p<0.05). There was no difference in the mechanical ventilation time, length of stay in ICU and hospital, and 28-day mortality between the two groups. CONCLUSIONS Compared with dobutamine, levosimendan reduces biomarkers of myocardial injury and improves systemic hemodynamics in patients with septic shock. However, it does not reduce the days on mechanical ventilation, length of stay in ICU and hospital, or 28-day mortality.

Probing the mechanism of cardiovascular drugs using a covalent levosimendan analog

One approach to improve contraction in the failing heart is the administration of calcium (Ca^2 +) sensitizers. Although it is known that levosimendan and other sensitizers bind to troponin C (cTnC), their in vivo mechanism is not fully understood. Based on levosimendan, we designed a covalent Ca^2 + sensitizer (i9) that targets C84 of cTnC and exchanged this complex into cardiac muscle. The NMR structure of the covalent complex showed that i9 binds deep in the hydrophobic pocket of cTnC. Despite slightly reducing troponin I affinity, i9 enhanced the Ca^2 + sensitivity of cardiac muscle. We conclude that i9 enhances Ca^2 + sensitivity by stabilizing the open conformation of cTnC. These findings provide new insights into the in vivo mechanism of Ca^2 + sensitization and demonstrate that directly targeting cTnC has significant potential in cardiovascular therapy.

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A Ca^2 + sensitizer, i9 was designed that forms a covalent bond with C84 of cTnC.

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i9 stabilized the open state of the N-domain of cTnC.

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The structure of the covalent cTnC-cTnI-i9 complex was solved by NMR.

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The structure showed that i9 binds deep in the hydrophobic pocket of cTnC.

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Despite slightly reducing cTnI affinity, i9 enhanced the Ca^2 + sensitivity of cardiac muscle.

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.

New perspective in heart failure management: could myosin activators be the answer?

Heart failure is a worldwide leading cause of hospital admissions. There is a critical need for new methods of management in acute heart failure. The current drug panel available in the treatment of hemodinamically unstable patients is not only limited, but it is also associated with deleterious side effects. Discoveries in the heart failure field seemed to lack an adequate answer and a change in paradigm may be necessary. The cardiac myosin activator omecamtiv mecarbil is a new therapeutic approach that improves the myocardial contractility through an innovative mechanism, avoiding the harmful effects of currently used inotropic agents. Several studies provided us with promising results, but further scientific proofs are needed.