Additive Impact of Interleukin 6 and Neuron Specific Enolase for Prognosis in Patients With Out-of-Hospital Cardiac Arrest – Experience From the HAnnover COoling REgistry

Predictive Performance of Neuron-Specific Enolase (NSE) for Survival after Resuscitation from Cardiac Arrest: A Systematic Review and Meta-Analysis

The prediction of outcomes following cardiac arrest continues to provide significant difficulties. A preferred strategy involves adopting a multimodal approach, which encompasses the careful evaluation of the biomarker neuron-specific enolase (NSE). This systematic review and meta-analysis aimed to gather and summarize new and existing evidence on the prediction effect of neuron-specific enolase for survival to hospital discharge among adult patients with cardiac arrest. We searched PubMed Central, Scopus, EMBASE databases, and the Cochrane Library without language restrictions from their inceptions until 30 October 2023 and checked the reference lists of the included studies. Pooled results were reported as standardized mean differences (SMDs) and were presented with corresponding 95% confidence intervals (CIs). The primary outcome was survival to hospital discharge (SHD). Eighty-six articles with 10,845 participants were included. NSE showed a notable degree of specificity in its ability to predict mortality as well as neurological status among individuals who experienced cardiac arrest (p < 0.05). This study demonstrates the ability to predict fatality rates and neurological outcomes, both during the time of admission and at various time intervals after cardiac arrest. The use of NSE in a multimodal neuroprognostication algorithm has promise in improving the accuracy of prognoses for persons who have undergone cardiac arrest.

Prehospital high-dose methylprednisolone in resuscitated out-of-hospital cardiac arrest patients (STEROHCA): a randomized clinical trial

PURPOSE

Patients who are successfully resuscitated following out-of-hospital cardiac arrest (OHCA) are still at a high risk of neurological damage and death. Inflammation and brain injury are components of the post-cardiac arrest syndrome, and can be assessed by systemic interleukin 6 (IL-6) and neuron-specific enolase (NSE). Anti-inflammatory treatment with methylprednisolone may dampen inflammation, thereby improving outcome. This study aimed to determine if prehospital high-dose methylprednisolone could reduce IL-6 and NSE in comatose OHCA patients.

METHODS

The STEROHCA trial was a randomized, blinded, placebo-controlled, phase II prehospital trial performed at two cardiac arrest centers in Denmark. Resuscitated comatose patients with suspected cardiac etiology were randomly assigned 1:1 to a single intravenous injection of 250 mg methylprednisolone or placebo. The co-primary outcome was reduction of IL-6 and NSE-blood levels measured daily for 72 h from admission. The main secondary outcome was survival at 180 days follow-up.

RESULTS

We randomized 137 patients to methylprednisolone (n = 68) or placebo (n = 69). We found reduced IL-6 levels (p < 0.0001) in the intervention group, with median (interquartile range, IQR) levels at 24 h of 2.1 pg/ml (1.0; 7.1) and 30.7 pg/ml (14.2; 59) in the placebo group. We observed no difference between groups in NSE levels (p = 0.22), with levels at 48 h of 18.8 ug/L (14.4; 24.6) and 14.8 ug/L (11.2; 19.4) in the intervention and placebo group, respectively. In the intervention group, 51 (75%) patients survived and 44 (64%) in the placebo group.

CONCLUSION

Prehospital treatment with high-dose methylprednisolone to resuscitated comatose OHCA patients, resulted in reduced IL-6 levels after 24 h, but did not reduce NSE levels.

Inflammatory response after out-of-hospital cardiac arrest-Impact on outcome and organ failure development

BACKGROUND

Post-cardiac arrest syndrome that occurs in out-of-hospital cardiac arrest (OHCA) patients is characterized by inflammatory response. We conducted a scoping review of current evidence regarding several inflammatory markers' usefulness for assessment of patient outcome and illness severity. We also discuss the proposed underlying mechanisms leading to inflammatory response after OHCA.

METHODS

We searched the MEDLINE, PubMed Central, Cochrane CENTRAL and Web of Science Core Collection databases with the following search terms: ("inflammation" OR "cytokines") AND "out-of-hospital cardiac arrest." Each inflammatory marker found was combined with "out-of-hospital cardiac arrest" using "AND" to find further relevant studies. We included original studies measuring inflammatory markers in adult OHCA patients that assessed their prognostic capabilities for mortality, neurological outcome, or organ failure severity.

RESULTS

Fifty-nine studies met the inclusion criteria, covering in total 65 different markers. Interleukin-6 (IL-6), procalcitonin (PCT) and C-reactive protein (CRP) were the most studied markers, and they were associated with poor outcomes in 13/15, 13/14 and 11/17 studies, respectively. Based on area under the receiver operating characteristic curve (AUC) value, the time point of best discriminatory capacity for poor outcome was ICU admission for IL-6 (median AUC 0.78, range 0.71-0.98) and day one after OHCA for PCT (median AUC 0.84, range 0.61-0.98). Seven studies reported AUCs for CRP (range 0.52-0.76) with no measurement time point being superior to others. The association of IL-6 and PCT with outcome appeared stronger in studies with more severely ill patients. Studies reported conflicting results regarding each marker's association with organ failure severity.

CONCLUSION

Inflammatory markers are potentially useful for early risk stratification after OHCA. PCT and IL-6 have moderate prognostic value during the first 24 h of the ICU stay. Predictive accuracy appears to be associated with the study overall event rate.

Cytokine hemoadsorption with CytoSorb® in post-cardiac arrest syndrome, a pilot randomized controlled trial

BACKGROUND

Hemoadsorption (HA) might mitigate the systemic inflammatory response associated with post-cardiac arrest syndrome (PCAS) and improve outcomes. Here, we investigated the feasibility, safety and efficacy of HA with CytoSorb® in cardiac arrest (CA) survivors at risk of PCAS.

METHODS

In this pilot randomized controlled trial, we included patients admitted to our intensive care unit following CA and likely to develop PCAS: required norepinephrine (> 0.2 µg/kg/min), and/or had serum lactate > 6 mmol/l and/or a time-to-return of spontaneous circulation (ROSC) > 25 min. Those requiring ECMO or renal replacement therapy were excluded. Eligible patients were randomly allocated to either receive standard of care (SOC) or SOC plus HA. Hemoadsorption was performed as stand-alone therapy for 24 h, using CytoSorb® and regional heparin-protamine anticoagulation. We collected feasibility, safety and clinical data as well as serial plasma cytokines levels within 72 h of randomization.

RESULTS

We enrolled 21 patients, of whom 16 (76%) had out-of-hospital CA. Median (IQR) time-to-ROSC was 30 (20, 45) minutes. Ten were assigned to the HA group and 11 to the SOC group. Hemoadsorption was initiated in all patients allocated to the HA group within 18 (11, 23) h of ICU admission and conducted for a median duration of 21 (14, 24) h. The intervention was well tolerated except for a trend for a higher rate of aPTT elevation (5 (50%) vs 2 (18%) p = 0.18) and mild (100-150 G/L) thrombocytopenia at day 1 (5 (50%) vs 2 (18%) p = 0.18). Interleukin (IL)-6 plasma levels at randomization were low (< 100 pg/mL) in 10 (48%) patients and elevated (> 1000 pg/mL) in 6 (29%). The median relative reduction in IL-6 at 48 h was 75% (60, 94) in the HA group versus 5% (- 47, 70) in the SOC group (p = 0.06).

CONCLUSIONS

In CA survivors at risk of PCAS, HA was feasible, safe and was associated with a nonsignificant reduction in cytokine plasma levels. Future trials are needed to further define the role of HA after CA. Those studies should include cytokine assessment to enrich the study population.

TRIAL REGISTRATION

NCT03523039, registered 14 May 2018.