Hemoadsorption eliminates remdesivir from the circulation: Implications for the treatment of COVID-19

The Effect of CytoSorb on Inflammatory Markers in Critically Ill Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVES

The effectiveness of CytoSorb at removing inflammatory mediators in critically ill patients is controversial.

DATA SOURCES

Electronic databases were searched from inception to May 2023.

STUDY SELECTION

Randomized controlled trials reporting the effects of CytoSorb therapy on inflammatory parameters in critically ill patients with hyperinflammatory conditions were included.

DATA EXTRACTION

Two authors screened articles for eligibility, extracted data, and assessed the risk of bias, conflicts of interest, and certainty of evidence (CoE). The primary outcome was interleukin (IL)-6 at 1 day after initiation of the therapy. Secondary outcomes included various inflammatory markers at 1, 2, 3, and 5 days and mortality. Data were pooled if at least three trials reported the outcome of interest. We conducted meta-analyses of the data using a random-effects model.

DATA SYNTHESIS

Seventeen trials ( n = 855) were included. Fourteen trials were judged to have notable concern about conflicts of interest. Seven trials were performed in medical ICU patients with hyperinflammatory conditions and 10 in complex cardiovascular surgery under cardiopulmonary bypass. Hemoadsorption with CytoSorb was not associated with lower IL-6 at 1 day (mean difference -5.98 [95% CI, -30.44 to 18.48] pg/mL), 2 days, 3 days, or 5 days after initiation of the treatment, as well as the concentration of procalcitionin. The levels of C-reactive protein were not lower with CytoSorb at 1, 2, and 3 days. The use of CytoSorb was associated with higher mortality at latest follow-up (relative risk = 1.22 [95% CI, 1.02-1.45]) and at 30 days. CoE ranged from low to very low.

CONCLUSIONS

The use of CytoSorb hemoadsorption in a mixed population of critically ill patients with hyperinflammatory conditions does not exhibit a consistent decrease in IL-6 and other inflammatory parameters within the first 5 days of treatment. The significant uncertainty surrounding these findings highlights the need for further investigations.

Adverse outcomes with extracorporeal adsorbent blood treatments in toxic systemic inflammation: a perspective on possible mechanisms

Background

Extracorporeal blood purification (EBP) treatments may be used in patients with sepsis and related conditions to mitigate toxic systemic inflammation, prevent or reverse vital organ injury, and improve outcome. These treatments lack demonstrable efficacy, but are generally considered safe. However, since late 2020, four clinical studies of EBP treatment using adsorbent devices in inflammatory disease reported significantly increased patient mortality associated with the adsorbent treatments. Criticisms of study design and execution were published, but revealed no decisive flaws. None of these critiques considered possible toxic effects of the adsorbent treatments per se.

Perspective and conclusion

In adsorbent EBP treatment of systemic inflammatory disease the adsorbent media are deployed in patient blood or plasma flow for the purpose of broad spectrum, non-specific adsorptive removal of inflammatory mediators. Adsorption and sequestration of inflammatory mediators by adsorbent media is intended to reduce mediator concentrations in circulating blood and neutralize their activity. However, in the past two decades developments in both biomedical engineering and the science of cytokine molecular dynamics suggest that immobilization of inflammatory proteins on solid scaffolds or molecular carriers may stabilize protein structure and preserve or amplify protein function. It is unknown if these mechanisms are operative in EBP adsorbent treatments. If these mechanisms are operative, then the adsorbent medium could become reactive, promoting inflammatory activity which could result in negative outcomes. Considering the recent reports of harm with adsorbent treatments in diverse inflammatory conditions, caution urges investigation of these potentially harmful mechanisms in these devices. Candidate mechanisms for possible inquiry are discussed.

Hemoperfusion in the intensive care unit

Multiple organ failure following a septic event derives from immune dysregulation. Many of the mediators of this process are humoral factors (cytokines), which could theoretically be cleared by direct adsorption through a process called hemoperfusion. Hemoperfusion through devices, which bind specific molecules like endotoxin or theoretically provide non-specific adsorption of pro-inflammatory mediators has been attempted and studied for several decades with variable results. More recently, technological evolution has led to the increasing application of adsorption due to more biocompatible and possibly more efficient biomaterials. As a result, new indications are developing in this field, and novel tools are available for clinical use. This narrative review will describe current knowledge regarding technical concepts, safety, and clinical results of hemoperfusion. Finally, it will focus on the most recent literature regarding adsorption applied in critically ill patients and their indications, including recent randomized controlled trials and future areas of investigation. Clinical trials for the assessment of efficacy of hemoperfusion in septic patients should apply the explanatory approach. This includes a highly selected homogenous patient population. Enrichment criteria such as applying genetic signature and molecular biomarkers allows the identification of subphenotypes of patients. The intervention must be delivered by a multidisciplinary team of trained personnel. The aim is to maximize the signals for efficacy and safety. In a homogenous cohort, confounding uncontrolled variables are less likely to exist. Trials with highly selected populations have a high internal validity but poor generalizability. The parallel design described in the figure is robust and usually is required by regulatory agencies for the approval of a new treatment. Allocation concealment and randomization are key to minimize bias such as confirmation bias, observer bias. The intervention should be delivered following a strict protocol. Deviations from the protocol might negatively influence the potential effects of the therapies. Surrogates such as cytokine measurement are adequate primary outcomes in phase 3 trials with small sample size because there is a higher likelihood of finding positive results concerning surrogate markers than in respect with clinical outcomes. Once a trial shows positive results concerning surrogate markers, a rationale for another phase 3 trial exploring clinical outcomes is built, justifying the allocation of financial sources to the intended trial.

Mortality and adverse events of hemoadsorption with CytoSorb® in critically ill patients: a systematic review and meta-analysis of randomized controlled trials

Background

The effects and safety of extracorporeal hemoadsorption with CytoSorb® in critically ill patients with inflammatory conditions are controversial.

Methods

We performed a systematic review with meta‐analysis and trial sequential analysis (TSA) of randomized‐controlled trials to assess the mortality and safety of CytoSorb® therapy in critically ill patients with inflammatory conditions. Electronic databases were searched up to April 2022. The primary outcome was mortality at longest follow‐up and secondary outcomes included various adverse event (AE) outcomes. Conflict of interest and funding of each trial were assessed. We calculated relative risk (RR) and 95% confidence interval (CI).

Results

Fourteen published (n = 764) and 4 unpublished (n = 111) trials were included. Eight trials were performed in medical ICU patients and 10 in complex cardiac surgery. Ten trials had significant industrial funding or an author conflict of interest. Hemoadsorption with CytoSorb® was associated with higher mortality at latest follow‐up (16 trials, n = 807, 120 of 402 [29.85%] patients in the CytoSorb® group vs. 98 of 405 [24.20%] patients in the control group, RR = 1.24 [95% CI, 1.04–1.49], p = .02, [TSA‐adjusted CI, 0.92–1.68]) and at 30‐days or in‐hospital (11 trials, n = 727; RR = 1.41 [95% CI, 1.06–1.88], p = .02, [TSA‐adjusted CI, 0.44–4.62]). Only one trial reported the definition of adverse event, while detailed results were reported in 3 trials; the risk of adverse events was not higher with CytoSorb®. Certainty of evidence ranged from low to very low.

Conclusion

Low certainty of evidence showed that the use of CytoSorb® might increase mortality in critically ill patients with inflammatory conditions. Adverse events were frequent but underreported and not systematically evaluated. Industrial funding and conflict of interest were common. Considerable uncertainty about the findings does not allow firm conclusions and suggests a need for high‐quality randomized trials to clarify mortality and adverse events related to CytoSorb®.

Editorial Comment

Hemoadsorption with CytoSorb® have been used in critically ill patients despite lack of high quality data from RCTs suggesting any patient‐important benefits. The findings from this systematic review and meta‐analysis suggests an increased risk of adverse events including mortality. With no apparent benefits and at the same time risk of harm, use of hemoadsorption with CytoSorb® in daily clinical practice cannot be recommended at this time.

The Effects of Hemoadsorption on the Kinetics of Antibacterial and Antifungal Agents

The extracorporeal elimination of a pathogen or damage-associated molecular pattern via blood purification techniques is increasingly being used in patients with septic shock and other clinical conditions characterized by a life-threatening inflammatory response. The removal of these substances can be accomoplished by means of ultrafiltration or hemoadsorption. Independently from the blood putification technique used, they could also affect the clearance of antibacterial and antifungal agents with a potentially significant clinical impact. In our review, we describe the basic principles of ultrafiltration and hemoadsorption, the available devices for this latter and the existing experimental and clinical studies; the final paragraph is dedicated to practical considerations that can help clinicians to consider the clearance of antibiotics and antifungals attributable to these techniques to minimize the risk of a iatrogenic underdosage.

Fatal COVID-19 in a Child with Persistence of SARS-CoV-2 Despite Extensive Multidisciplinary Treatment: A Case Report

Critical Coronavirus disease 2019 (COVID-19) developed in a 7-year-old girl with a history of dystrophy, microcephaly, and central hypothyroidism. Starting with gastrointestinal symptoms, the patient developed severe myocarditis followed by progressive multiple organ failure complicated by Pseudomonas aeruginosa bloodstream infection. Intensive care treatment consisting of invasive ventilation, drainage of pleural effusion, and high catecholamine therapy could not prevent the progression of heart failure, leading to the implantation of venoarterial extracorporeal life support (VA-ECLS) and additional left ventricle support catheter (Impella^® pump). Continuous venovenous hemofiltration (CVVH) and extracorporeal hemadsorption therapy (CytoSorb^®) were initiated. Whole exome sequencing revealed a mutation of unknown significance in DExH-BOX helicase 30 (DHX30), a gene encoding a RNA helicase. COVID-19 specific antiviral and immunomodulatory treatment did not lead to viral clearance or control of hyperinflammation resulting in the patient’s death on extracorporeal life support-(ECLS)-day 20. This fatal case illustrates the potential severity of pediatric COVID-19 and suggests further evaluation of antiviral treatment strategies and vaccination programs for children.