Extracorporeal Cytokine Adsorption Therapy As a Preventive Measure in Cardiac Surgery and As a Therapeutic Add-On Treatment in Sepsis: An Updated Systematic Review of Comparative Efficacy and Safety

Extracorporeal Blood Purification and Acute Kidney Injury in Cardiac Surgery: The SIRAKI02 Randomized Clinical Trial

Importance

Cardiac surgery-associated acute kidney injury (CSA-AKI) remains a significant problem following cardiopulmonary bypass (CPB). Various strategies are proposed to attenuate CSA-AKI, including extracorporeal blood purification (EBP), but little is known about the effect of EBP through an acrylonitrile-sodium methallylsulfonate/polyethyleneimine membrane during CPB.

Objective

To determine whether the use of an EBP device in a nonemergent cardiac surgery population reduces CSA-AKI after CPB.

Design, Setting, and Participants

This double-blind, randomized clinical trial was conducted in 2 tertiary hospitals in Spain. Patients 18 years or older undergoing nonemergent cardiac surgery who were at high risk for CSA-AKI were enrolled from June 15, 2016, through November 5, 2021, with follow-up data through February 5, 2022. Of 1156 patients assessed, 343 patients were randomized (1:1) to either receive EBP or standard care.

Intervention

Nonselective EBP device connected to the CPB circuit.

Main Outcomes and Measures

The primary outcome was the rate of CSA-AKI in the 7 days after randomization.

Results

Among 343 patients randomized (169 to receive EBP and 174 to receive usual care), the mean (SD) age was 69 (9) years and 119 were females. The rate of CSA-AKI was 28.4% (95% CI, 21.7%-35.8%) in the EBP group vs 39.7% (95% CI, 32.3%-47.3%) in the standard care group (P = .03), with an adjusted difference of 10.4% (95% CI, 2.3%-18.5%) using a log-binomial model (P = .01). No significant differences (P > .05) were observed in most of the predefined clinical secondary end points or post hoc exploratory end points. In a sensitivity analysis, EBP was found to be more effective in terms of CSA-AKI reduction in patients with chronic kidney disease, diabetes, hypertension, low left ventricular ejection fraction (<40%), and lower body mass index (<30). No differences were observed between the groups in adverse events tracking.

Conclusions and Relevance

The use of a nonselective EBP device connected to the CPB circuit in a nonemergent population of patients undergoing cardiac surgery was associated with a significant reduction of CSA-AKI in the first 7 days after surgery.

Trial Registration

ClinicalTrials.gov Identifier: NCT02518087.

Cardiac Surgery-Associated Acute Kidney Injury

AKI is a common and serious complication of cardiac surgery that has a significant impact on patient morbidity and mortality. The Kidney Disease Improving Global Outcomes definition of AKI is widely used to classify and identify AKI associated with cardiac surgery (cardiac surgery-associated AKI [CSA-AKI]) on the basis of changes in serum creatinine and/or urine output. There are various preoperative, intraoperative, and postoperative risk factors for the development of CSA-AKI which should be recognized and addressed as early as possible to expedite its diagnosis, reduce its occurrence, and prevent or ameliorate its devastating complications. Crucial issues are the inaccuracy of serum creatinine as a surrogate parameter of kidney function in the perioperative setting of cardiothoracic surgery and the necessity to discover more representative markers of the pathophysiology of AKI. However, except for the tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 ratio, other diagnostic biomarkers with an acceptable sensitivity and specificity are still lacking. This article provides a comprehensive review of various aspects of CSA-AKI, including pathogenesis, risk factors, diagnosis, biomarkers, classification, prevention, and treatment management.

Extreme obesity is a strong predictor for in-hospital mortality and the prevalence of long-COVID in severe COVID-19 patients with acute respiratory distress syndrome

Acute Respiratory Distress Syndrome (ARDS) is common in COVID-19 patients and is associated with high mortality. The aim of this observational study was to describe patients' characteristics and outcome, identifying potential risk factors for in-hospital mortality and for developing Long-COVID symptoms. This retrospective study included all patients with COVID-19 associated ARDS (cARDS) in the period from March 2020 to March 2021 who were invasively ventilated at the intensive care unit (ICU) of the University Hospital Dresden, Germany. Between October 2021 and December 2021 patients discharged alive (at minimum 6 months after hospital discharge-midterm survival) were contacted and interviewed about persistent symptoms possibly associated with COVID-19 as well as the quality of their lives using the EQ-5D-5L-questionnaire. Long-COVID was defined as the occurrence of one of the symptoms at least 6 months after discharge. Risk factors for mortality were assessed with Cox regression models and risk factors for developing Long-COVID symptoms by using relative risk (RR) regression. 184 Patients were included in this study (male: n = 134 (73%), median age 67 (range 25-92). All patients were diagnosed with ARDS according to the Berlin Definition. 89% of patients (n = 164) had severe ARDS (Horovitz-index < 100 mmHg). In 27% (n = 49) extracorporeal membrane oxygenation was necessary to maintain gas exchange. The median length of in-hospital stay was 19 days (range 1-60). ICU mortality was 51%, hospital mortality 59%. Midterm survival (median 11 months) was 83% (n = 55) and 78% (n = 43) of these patients presented Long-COVID symptoms with fatigue as the most common symptom (70%). Extreme obesity (BMI > 40 kg/m2) was the strongest predictor for in-hospital mortality (hazard ratio: 3.147, confidence interval 1.000-9.897) and for developing Long-COVID symptoms (RR 1.61, confidence interval 1.26-2.06). In-hospital mortality in severe cARDS patients was high, but > 80% of patients discharged alive survived the midterm observation period. Nonetheless, most patients developed Long-COVID symptoms. Extreme obesity with BMI > 40 kg/m2 was identified as independent risk factor for in-hospital mortality and for developing Long-COVID symptoms.Trial registration DRKS-ID DRKS00027856.

Vasoplegic Syndrome after Cardiopulmonary Bypass in Cardiovascular Surgery: Pathophysiology and Management in Critical Care

Vasoplegic syndrome (VS) is a common complication following cardiovascular surgery with cardiopulmonary bypass (CPB), and its incidence varies from 5 to 44%. It is defined as a distributive form of shock due to a significant drop in vascular resistance after CPB. Risk factors of VS include heart failure with low ejection fraction, renal failure, pre-operative use of angiotensin-converting enzyme inhibitors, prolonged aortic cross-clamp and left ventricular assist device surgery. The pathophysiology of VS after CPB is multi-factorial. Surgical trauma, exposure to the elements of the CPB circuit and ischemia-reperfusion promote a systemic inflammatory response with the release of cytokines (IL-1β, IL-6, IL-8, and TNF-α) with vasodilating properties, both direct and indirect through the expression of inducible nitric oxide (NO) synthase. The resulting increase in NO production fosters a decrease in vascular resistance and a reduced responsiveness to vasopressor agents. Further mechanisms of vasodilation include the lowering of plasma vasopressin, the desensitization of adrenergic receptors, and the activation of ATP-dependent potassium (KATP) channels. Patients developing VS experience more complications and have increased mortality. Management includes primarily fluid resuscitation and conventional vasopressors (catecholamines and vasopressin), while alternative vasopressors (angiotensin 2, methylene blue, hydroxocobalamin) and anti-inflammatory strategies (corticosteroids) may be used as a rescue therapy in deteriorating patients, albeit with insufficient evidence to provide any strong recommendation. In this review, we present an update of the pathophysiological mechanisms of vasoplegic syndrome complicating CPB and discuss available therapeutic options.

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.

Application of Adsorptive Blood Purification Techniques during Cardiopulmonary Bypass in Cardiac Surgery

By reason of surgical demand, the majority of cardiovascular procedures still depend on the use of cardiopulmonary bypass (CPB). Due to the nonphysiological state of CPB, it can cause complex and unpredictable inflammatory response, which may lead to significant morbidity and mortality. Unfortunately, the pharmacological and mechanical strategies that currently exist do not offer significant advantages in controlling inflammatory response and improving patient outcomes. The best strategy to reduce inflammation in CPB is still uncertain. In recent years, adsorptive blood purification techniques (BPTs) have emerged, among which CytoSorb is the latest representative device. Currently, the primary application area of adsorptive BPTs is in the control and treatment of systemic hyperinflammatory states, such as refractory septic shock patients. However, the evidences on efficacy and safety of adsorptive BPTs application during CPB surgery are still inconclusive, so we summarize the relevant evidences here and suggest future potential research areas.

The use of a hemoperfusion column that removes endotoxin and cytokines in the complex therapy of widespread peritonitis complicated by septic shock

А clinical case of septic shock treatment with new approved for clinical use hemoperfusion columns Efferon LPS of multi-purpose action, which are capable of removing LPS and cytokines from the blood, is presented. A 75-year-old patient 8 hours after surgery for widespread peritonitis, which developed due to obturation intestinal obstruction and rupture of the cecum, in a state of septic shock (SOFA 10, sympathomimetic support with norepinephrine 0.56 μg/kg per minute) underwent in addition to the treatment 2 sessions of hemoperfusion (120 minutes each) with an interval of two days. The next day after the first session of hemoperfusion, blood pressure returned to normal. Over the next 5 days, impaired organ functions gradually recovered (SOFA dynamics from 10 to 1 point) and the level of procalcitonin in the blood decreased from 98 to 5 ng/ml. A decrease in the concentration of IL-6 in the blood was noted: from 1686 to 1388 pg/ml after the first session, from 692 to 411 pg/ml after the second and up to 350 pg/ml on the following days. The content of CD14+ blood monocytes also decreased: from 0.13·109/l to 0.03·109/l after the first session and from 0.30·109/l to 0.18·109/l after the second. The patient was in intensive care for 8 days and was discharged from the hospital after 24 days. The use of hemoperfusion column for the adsorption of cytokines and LPS in an extremely severe patient with septic shock was safe. One of the effects of using the column was the removal of LPS-activated CD14+ monocytes and CD14+ granulocytes from the blood, which helped to reduce systemic inflammation and the severity of multiple organ disorders.

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.

Effects of the timing and intensity of treatment on septic shock patients treated with CytoSorb®: Clinical experience

INTRODUCTION

A group of adult septic shock patients treated with hemoperfusion (HA) with the Cytosorb^® associated with CVVHD were studied to determine (a) the effects of this technique on different clinical variables; and (b) the impact of the pre CytoSorb^® interval and its intensity on the outcome.

METHODS

The catecholamine index (CI) and the pressure-catecholamine Index (PCAI) were used to assess the amount of catecholamine administered at baseline and during the procedure, respectively. The pre-treatment time was calculated since the onset of the septic-shock related hypotension and the initiation of the first session and the intensity was assessed considering either the total volume of blood processed and the duration of the HA.

RESULTS

Overall, 51 patients with septic shock (30 m, 21 f), age 68 years (IQR 59-76) were retrospectively enrolled in the study; 26 were discharged alive form the ICU (S) and 25 died in ICU (NS); in the S group either CI and PCAI decreased significantly but in NS the CI increased and the PCAI remained stable in NS. In S, the time elapsing from the onset of symptoms and the start of Cytosorb^® was shorter than in NS; the duration of the treatment and the volume of blood processed were significantly higher in S than in NS.

CONCLUSIONS

In this group of septic shock patients, the earlier initiation of Cytosorb^®, its longer duration and the higher volume of blood processed were associated with a better survival.