Population Pharmacokinetics of Levosimendan and its Metabolites in Critically Ill Neonates and Children Supported or Not by Extracorporeal Membrane Oxygenation

Assessing the Impact of Multiple Imputation Algorithms on Pharmacokinetic Model Performance: A Simulation-Based Study

This study compared multiple imputation (MI) algorithms in a one-compartment pharmacokinetic (PK) scenario with oral absorption. Four covariates (two continuous, two dichotomous) linked to PK parameters were randomly removed under a missing completely at random (MCAR) mechanism. The aim was to identify which algorithm best preserves covariate distributions and PK parameter estimates. The original dataset included 100 individuals, each with five sampling occasions. Missing data were introduced at 5%, 20%, 50%, and 75% for the four covariates under the MCAR assumption. Five MI algorithms (Mice, Amelia, missForest, rMIDAS, XGBoost) were tested. Absolute and relative errors and concordance metrics were used to assess performance. Population and individual parameter estimates were compared across imputed and original datasets using Monolix2024R1®. MissForest (MF) and Amelia yielded lower errors for continuous covariates whereas dichotomous variables were poorly imputed. Based on objective function values, Mice perform best at 5% and MF at 20% of missingness. Increasing missingness decreased covariate effects and increased the estimated inter-individual variances. Individual parameter estimation accurately captured individual-level variability across all imputed datasets. MI methods appear effective for covariate imputation in PK modeling, offering reliable results up to 20% missingness under an MCAR mechanism. Future research should explore refined strategies, including advanced modeling frameworks and Bayesian approaches for imputation. Enhancing our understanding of missing data processes will be crucial for robust PK analyses across diverse clinical settings.

Highly sensitive ultra-high-performance liquid chromatography coupled with tandem mass spectrometry method for the multiplex analysis of levosimendan and its metabolites OR-1855 and OR-1896 in human plasma

Levosimendan is a positive inotrope and vasodilator used in patients with acute and chronic decompensated heart failure. It is metabolized into OR-1855 (inactive metabolite), which is further acetylated into OR-1896 (active metabolite having a prolonged half-life, hence a sustained effect). Levosimendan represents a valuable alternative to traditional inotropes with broad clinical applications in critically ill patients with cardiogenic shock, advanced heart failure and post-cardiac surgery. However, while levosimendan demonstrates dose-dependent hemodynamic effects, its pharmacokinetics has not yet been investigated in adult critically ill patients, a vulnerable population characterized by complex and unstable conditions that may significantly alter drug disposition. Therefore, pharmacokinetics studies of levosimendan and metabolites in critically ill patients require a reliable and sensitive quantification method. We developed and validated a highly sensitive method using ultra-high-performance liquid-chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) for the quantification of levosimendan, OR-1855 and OR-1896 in human plasma. To achieve the required analytical sensitivity, plasma sample preparation included protein precipitation with acetonitrile, subsequent supernatant's evaporation to dryness under nitrogen, and reconstitution of the solid residues with a solution of H2O:MeOH 4:1, followed by a 40 µL-aliquot injection into the LC column. Chromatographic separation of the three analytes was achieved in a 6-minute run in gradient mode, using an Acquity UPLC BEH C18 1.7 µm, 2.1 × 150 mm column. The method was extensively validated according to international bioanalytical assay guidelines, on a clinically relevant concentration range of 0.1-100 ng/mL, for each analyte. Considering these very low concentrations, the assay showed excellent performances in terms of trueness (94.3-105.3 %), repeatability (1.9-7.2 %) and intermediate fidelity (2.3-9.7 %). Of note, during our ex vivo studies on whole blood samples stability, acetylation of the metabolite OR-1855 into the active OR-1896 metabolite was observed in the presence of red blood cells. The UHPLC method is being applied for a prospective observational pharmacokinetics study of levosimendan in patients undergoing extracorporeal membrane oxygenation support. The benefit of levosimendan therapeutic drug monitoring in intensive care patients remains to be assessed.

Bibliometric analysis of levosimendan

Background

Levosimendan (LEVO), a calcium sensitizer and adenosine triphosphate-dependent potassium channel opener, has been widely used for decades in medical and surgical patients for advanced heart failure (HF), right ventricular failure, cardiogenic shock, takotsubo cardiomyopathy, pulmonary hypertension, and so on. Currently, as the limited scope and lack of comprehensive data in current LEVO publications, there is an increasing obstacle to conducting new studies that require integrated information and quantifiable results. Thus, the current study was performed to identify the research trends and hot spots in LEVO-related publications using bibliometric software.

Methods

LEVO-related publications from 1990 to 2023 were searched and retrieved in the Web of Science Core Collection (WoSCC) and analyzed with VOSviewer, CiteSpace, Scimago Graphica, R-bibliometrix and Rstudio for publication dates, countries/regions, institutions, authors, keywords, journals, and references.

Results

Finally, a total of 1,432 LEVO-related articles were included in the present study. Annual LEVO-related publications have been increased yearly. The United States was the most productive country with 243 articles. The University of Helsinkin published 69 articles in the field of LEVO, which were the most productive institution among all the institutions. Of all the authors, professor Pollesello,Piero was the most productive author with 62 articles. Moreover, the results of the co-citation analysis and citation bursts analysis revealed that the safety and effectiveness of LEVO were the global research trends and potential hot spots.

Conclusions

This study systematically summarizes the current status in the field of LEVO and provides insights into the research focuses and future hotspots.

Systematic Review of Ex Vivo and In Vivo Pharmacokinetic Studies of Drugs Commonly Used During Extracorporeal Membrane Oxygenation

Extracorporeal membrane oxygenation (ECMO) is a lifesaving treatment for critically ill patients in cardiac or respiratory failure refractory to conventional treatment. Patients on an ECMO circuit (pump, oxygenator, tubing) require numerous medications including sedatives, analgesics, cardioactive medications, and anticonvulsants. Currently, there are few dosing guidelines to optimize pharmacotherapy in this situation. A systematic review was conducted to describe pharmacokinetics (PK) of medications commonly used during ECMO. MEDLINE, Embase, Cochrane, BIOSIS, PubMed, and Web of Science databases were searched. All articles presenting ex vivo, animal, and human data on the PK of the subject medications in the ECMO circuit were included. Three authors independently examined citation titles and abstracts. Four authors extracted relevant details from included studies into standardized data extraction forms. Methodological quality was assessed using the ClinPK guidelines and the Joanna Briggs Institute Checklist. Forty-four studies examining 30 medications were included, 26 ex vivo studies (mostly adult circuits) and 18 observational studies (mainly neonatal patients). Pharmacokinetics varied depending on the medication's characteristics, study type, and population. Study quality was variable, limiting the possibility of deriving hard dosing guidelines from this available literature. Further population PK studies are needed to adequately determine dosing guidelines in adults and children requiring ECMO.

An Update on Pharmacologic Management of Neonatal Hypotension: When, Why, and Which Medication

Anti-hypotensive treatment, which includes dopamine, dobutamine, epinephrine, norepinephrine, milrinone, vasopressin, terlipressin, levosimendan, and glucocorticoids, is a long-established intervention in neonates with arterial hypotension (AH). However, there are still gaps in knowledge and issues that need clarification. The main questions and challenges that neonatologists face relate to the reference ranges of arterial blood pressure in presumably healthy neonates in relation to gestational and postnatal age; the arterial blood pressure level that potentially affects perfusion of critical organs; the incorporation of targeted echocardiography and near-infrared spectroscopy for assessing heart function and cerebral perfusion in clinical practice; the indication, timing, and choice of medication for each individual patient; the limited randomized clinical trials in neonates with sometimes conflicting results; and the sparse data regarding the potential effect of early hypotension or anti-hypotensive medications on long-term neurodevelopment. In this review, after a short review of AH definitions used in neonates and existing data on pathophysiology of AH, we discuss currently available data on pharmacokinetic and hemodynamic effects, as well as the effectiveness and safety of anti-hypotensive medications in neonates. In addition, data on the comparisons between anti-hypotensive medications and current suggestions for the main indications of each medication are discussed.