Outcome and prognostication after cardiac arrest

LncRNA ENSSSCG00000035331 Alleviates Hippocampal Neuronal Ferroptosis and Brain Injury Following Porcine Cardiopulmonary Resuscitation by Regulating the miR-let7a/GPX4 Axis

BACKGROUND

Following successful cardiopulmonary resuscitation, those survivors of cardiac arrest (CA) often suffer from severe brain injury, and the latter can result in significant mortality and morbidity. Emerging evidence implicates that ferroptosis is involved in the pathogenesis of post-resuscitation brain injury, and its regulatory mechanisms remain to be investigated. Recently, some studies manifested that long noncoding RNAs could be critical regulators of cell ferroptosis in diverse ischemia-reperfusion injuries of vital organs. This study was designed to explore the role and mechanism of a newly screened long noncoding RNA ENSSSCG00000035331 in alleviating post-resuscitation hippocampal neuronal ferroptosis and further investigate its potential regulation by a novel antioxidant sulforaphane.

METHODS AND RESULTS

Healthy male pigs and mice were used to establish the models of CA and resuscitation in vivo. A hypoxia/reoxygenation (H/R) model using primary porcine hippocampal neurons was constructed to replicate post-resuscitation brain injury in vitro. We found that the expression of ENSSSCG00000035331 was significantly decreased in the post-resuscitation impaired hippocampus using RNA sequencing analysis and verification. Subsequently, ENSSSCG00000035331 overexpression significantly reduced ferroptosis-related ferrous iron and reactive oxygen species production while markedly increased glutathione and further alleviated post-resuscitation brain injury. Mechanistically, ENSSSCG00000035331 interacted with miR-let7a, then inhibited its binding with glutathione peroxidase 4 (GPX4) mRNA and finally promoted the recovery of the latter's translation after H/R stimulation. In addition, sulforaphane treatment significantly increased ENSSSCG00000035331 and GPX4 expression while markedly decreased miR-let7a expression and hippocampal neuronal ferroptosis and finally alleviated post-resuscitation brain injury.

CONCLUSIONS

Our findings highlighted that ENSSSCG00000035331 was a critical regulator of hippocampal neuronal ferroptosis after CA and resuscitation by targeting the miR-let7a/GPX4 axis, and additionally, sulforaphane might be a promising therapeutic agent for alleviating post-resuscitation brain injury by regulating the signaling axis mentioned above.

Prediction of Mortality After Convulsive Status Epilepticus: The Status Epilepticus M3A2S2H Score

PurposeThis study aimed to investigate in-patient mortality and predictors of death associated with convulsive status epilepticus (CSE) in a large nationwide cohort and create a simplified predictive score for in-hospital mortality.MethodsRetrospective data from the National Inpatient Sample (NIS) database between 2007 and 2014 were analyzed, including 123,082 adults with CSE. Univariate logistic testing identified admission variables, neurological and medical complications associated with mortality. A simplified clinical prediction score, called M3A2S2H, was generated using variables that were frequent (>1%) and had a significant impact on mortality.ResultsThe overall hospital mortality rate was 3.5%. Univariate analysis revealed that older age, female gender, past medical history, and acute hospital conditions were related to mortality. After reclassification, a final multivariable model with 27 clinical variables was constructed, and the eight strongest predictors were included in the M3A2S2H score: hypoxic-ischemic encephalopathy/cardiac arrest (2 points); age >60 years, acute symptomatic CSE, invasive mechanical ventilation, sepsis, metastases, and chronic liver failure (all 1 point); and medication nonadherence (-1 point). The mortality rate among patients with ≤0, 1, 2, 3, 4, or ≥5 of these risk factors progressively increased from 0.2%, 2.1%, 7.8%, 20.3%, 31.9%, to 50.0% (P < 0.0001). Additionally, a similar stepwise trend was observed regarding discharge to a facility versus home without services (P < 0.0001).ConclusionsThis study demonstrates that mortality in CSE cases occurs in 3.5% of adult hospital admissions. Identification of specific acute and chronic conditions using the standardized M3A2S2H score can help predict the risk of death or disability even in hospitals without advanced brain monitoring.

Triglyceride-glucose index correlates with the incidences and prognoses of cardiac arrest following acute myocardial infarction: data from two large-scale cohorts

BACKGROUND

The triglyceride-glucose (TyG) index, renowned for its efficacy and convenience in assessing insulin resistance, has been validated as a reliable indicator for various cardiovascular conditions. The current study aims for clarifying the link of TyG with the incidences and prognoses of cardiac arrest (CA) following acute myocardial infarction (AMI).

METHODS

Our analysis is a multicenter, retrospective study utilizing data from the Medical Information Mart for Intensive Care IV and the eICU Collaborative Research Database. Patients with AMI for whom TyG could be calculated within the first 24 h after admission were included. The main endpoints were in-hospital and ICU mortalities. Correlations between TyG and outcomes were evaluated using logistic regression models, restricted cubic splines (RCS), as well as correlation and linear analyses. Overlap weighting (OW), inverse probability of treatment weighting (IPTW), and propensity score matching (PSM) methodologies were utilized to balance the cohorts, thereby minimizing potential biases. Subgroup analyses were performed in accordance with identified modifiers.

RESULTS

In total, 5208 individuals diagnosed with AMI, among whom 371 developed CA, were ultimately included. Higher TyG levels were observed among AMI populations with CA compared to those without [9.2 (8.7-9.7) vs. 9.0 (8.5-9.4)], and TyG demonstrated a moderate discriminatory capacity for identifying CA occurrences within entire AMI populations. Multivariate logistic regressions revealed TyG serves a significant risk indicator for both in-hospital (OR 1.711) and ICU mortalities (OR 1.520) in AMI-CA patients, and it is also associated with prolonged LOSs. RCS analyses confirmed linear relationships of ascending TyG with increased mortality risks for AMI-CA (P for nonlinearity: 0.592 and 0.816, respectively), which persisted following PSM, OW, and IPTW adjustments. Subgroup analyses further identified a strong link of the TyG with mortality rates among elders, females, individuals with BMI < 28 kg/m2, and those with hypertension.

CONCLUSIONS

Elevated TyG levels were found to apparently correlate with higher prevalence and adverse outcomes regarding CA in patients with AMI. Our findings point a fresh insight into the significance of the TyG in critically ill coronary conditions.

Effect of hypercapnia on neurologic outcomes after cardiac arrest: A systematic review and meta-analysis

BACKGROUND

Brain injury often occurs after cardiac arrest, and the regulation of PaCO2 plays a crucial role in mediating cerebral blood flow. The current guidelines recommend maintaining normocapnia through ventilation in post-arrest patients. However, the effects of hypercapnia on neurological outcomes remain controversial. To address this issue, we undertook a meta-analysis to compare the effects of hypercapnia and normocapnia on the neurological outcomes in patients with cardiac arrest.

METHODS

As of December 5, 2023, we conducted a search on eligible studies, including EMBASE, PubMed, and WOS databases. Our primary outcome of interest was a good neurological outcome, and two authors independently screened the studies and extracted relevant data. For analysis, a fixed effects model was used when the I2 values were less than 50 %, whereas a random effects model was used for higher I2 values.

RESULTS

From the 2137 studies initially identified, seven studies involving 2770 patients were ultimately included. Compared with normocapnia, hypercapnia significantly improved the neurological outcomes of patients with cardiac arrest (OR 0.73; 95 % CI 0.56-0.96; P = 0.02). According to the subgroup analysis, the hypercapnic group achieved better neurological outcomes in the short-term than did the normocapnia group (OR 0.61; 95 % CI 0.42-0.88; P = 0.008), whereas no significant difference was observed in long-term (OR 0.91; 95 % CI 0.76-1.10; P = 0.35). Moreover, there was no significant difference in mortality between the two groups (OR 1.03; 95 % CI 0.65-1.63; P = 0.91).

CONCLUSION

Our results suggest that hypercapnia is associated with a good neurological prognosis, especially in the short-term setting. However, further well-powered randomized controlled trials are necessary to confirm the optimal PaCO2 targets.

PROSPERO

CRD42023457027. Registered 3 September 2023.

Application of high-quality targeted temperature management guided by multimodal brain monitoring in brain protection of patients with cardiac arrest: A case series

RATIONALE

Cardiac arrest (CA) is an acute emergency with high mortality and is closely associated with the risk of brain damage or systemic ischemia-reperfusion injury, post-traumatic stress symptoms.

PATIENT CONCERNS

Targeted temperature management in the intensive care unit can improve the neurological outcomes of patients who are comatose after resuscitation from CA. However, there is often a lack of specific evaluation methods for optimal target temperature settings.

DIAGNOSES

From November 2021 to October 2022, 9 CA patients received prompt cardiopulmonary resuscitation and return of spontaneous circulation after approximately 10 to 30 minutes of cardiopulmonary resuscitation in Xiangya Hospital, Central South University.

INTERVENTIONS

We retrospectively reviewed 9 CA patients' medical data, including demographic characteristics, hemodynamic change, clinically relevant score, imageological examination, transcranial Doppler ultrasonography, electroencephalogram (EEG), somatosensory-evoked potential, and laboratory data.

OUTCOMES

According to the result of each patient's transcranial Doppler ultrasonography, somatosensory-evoked potential, and EEG to formulate an individualized target temperature. Contrary to the internationally recommended target of hypothermia, we found that not all patients require hypothermia therapy to maintain normal cerebrovascular autonomic regulation function. And neuron-specific enolase and S100β in patients showed a downward trend after hypothermia therapy. Compared with before hypothermia treatment, clinically relevant scores were reduced in patients with good prognosis. Intracranial congestion or ischemia was improved and intracranial pressure was reduced in all patients during hypothermia treatment. For patients with good EEG response, the ratio of gray matter in the brain increased and the neurological prognosis was significantly improved. Finally, after 6 months of follow-up, we found 3 patients died and 1 patient had a long-term vegetative state, the other patients had a good prognosis.

LESSONS

Individualized targeted temperature management under the guidance of multimodal brain monitoring plays an important role in brain protection of patients with CA.

Prognosis and enhancement of recovery in disorders of consciousness

Disorders of consciousness after severe brain injury encompass conditions of coma, vegetative state/unresponsive wakefulness syndrome, and minimally conscious state. DoC clinical presentation pose perplexing challenges to medical professionals, researchers, and families alike. The outcome is uncertain in the first weeks to months after a brain injury, with families and medical providers often making important decisions that require certainty. Prognostication for individuals with these conditions has been the subject of intense scientific investigation that continues to strive for valid prognostic indicators and algorithms for predicting recovery of consciousness. This manuscript aims to provide an overview of the current clinical landscape surrounding prognosis and optimizing recovery in DoC and the current and future research that could improve prognostic accuracy after severe brain injury. Improved understanding of these factors will aid healthcare professionals in providing optimal care, fostering hope, and advocating for ethical practices in the management of individuals with DoC.

PREDICTIVE VALUE OF NEUTROPHIL EXTRACELLULAR TRAP COMPONENTS FOR 28-DAY ALL-CAUSE MORTALITY IN PATIENTS WITH CARDIAC ARREST: A PILOT OBSERVATIONAL STUDY

ABSTRACT

Background: Ischemia-reperfusion after cardiac arrest (CA) activates peptidyl arginine deiminase and citrullinated histone H3 (CitH3), which leads to the formation of neutrophil extracellular traps (NETs). This study attempted to determine the alterations in NET components in post-CA patients as well as analyze the association of NETs with 28-day all-cause mortality. Methods : In this study, 95 patients with restoration of spontaneous circulation (ROSC) after CA were included. They were categorized into the survivor group (n = 32) and the nonsurvivor group (n = 63) according to their 28-day survival statuses. The control group comprised 20 healthy individuals. The blood samples were collected from the patients on days 1, 3, and 7 after ROSC and from the control subjects at the time of enrollment. The serum cell-free DNA (cfDNA) level was determined using the fluorescent labeling method, and the serum concentrations of NET components, including CitH3, myeloperoxidase, neutrophil elastase, and nucleosomes, were estimated using the enzyme-linked immunosorbent assay. Results : Compared with the control group, the serum NET components were significantly increased in the patients 1 week after ROSC (all P < 0.05). These components were significantly higher in the nonsurvivor group than in the survivor group (all P < 0.05). Spearman correlational analysis revealed that the components were positively correlated with Acute Physiology and Chronic Health Evaluation II scores (both P < 0.05). Binary logistic regression analysis indicated that serum cfDNA, CitH3, and nucleosomes on days 1 and 3 after ROSC were independent predictors of 28-day all-cause mortality. Furthermore, these parameters on day 1 after ROSC had the biggest areas under the receiver operating characteristic curves (0.876, 0.862, and 0.861, respectively). Conclusions: Elevated serum levels of cfDNA, CitH3, myeloperoxidase, neutrophil elastase, and nucleosomes were positively correlated with disease severity after ROSC. However, only serum CitH3, cfDNA, and nucleosomes on day 1 after ROSC showed a good predictive value for 28-day all-cause mortality.

Triglyceride-glucose index is associated with the occurrence and prognosis of cardiac arrest: a multicenter retrospective observational study

BACKGROUND

Triglyceride-glucose (TyG) index is an efficient indicator of insulin resistance and is proven to be a valuable marker in several cardiovascular diseases. However, the relationship between TyG index and cardiac arrest (CA) remains unclear. The present study aimed to investigate the association of the TyG index with the occurrence and clinical outcomes of CA.

METHODS

In this retrospective, multicenter, observational study, critically ill patients, including patients post-CA, were identified from the eICU Collaborative Research Database and evaluated. The TyG index for each patient was calculated using values of triglycerides and glucose recorded within 24 h of intensive care unit (ICU) admission. In-hospital mortality and ICU mortality were the primary clinical outcomes. Logistic regression, restricted cubic spline (RCS), and correlation analyses were performed to explore the relationship between the TyG index and clinical outcomes. Propensity score matching (PSM), overlap weighting (OW), and inverse probability of treatment weighting (IPTW) were adopted to balance the baseline characteristics of patients and minimize selection bias to confirm the robustness of the results. Subgroup analysis based on different modifiers was also performed.

RESULTS

Overall, 24,689 critically ill patients, including 1021 patients post-CA, were enrolled. The TyG index was significantly higher in patients post-CA than in those without CA (9.20 (8.72-9.69) vs. 8.89 (8.45-9.41)), and the TyG index had a moderate discrimination ability to identify patients with CA from the overall population (area under the curve = 0.625). Multivariate logistic regression indicated that the TyG index was an independent risk factor for in-hospital mortality (OR = 1.28, 95% CI: 1.03-1.58) and ICU mortality (OR = 1.27, 95% CI: 1.02-1.58) in patients post-CA. RCS curves revealed that an increased TyG index was linearly related to higher risks of in-hospital and ICU mortality (P for nonlinear: 0.225 and 0.271, respectively). Even after adjusting by PSM, IPTW, and OW, the TyG index remained a risk factor for in-hospital mortality and ICU mortality in patients experiencing CA, which was independent of age, BMI, sex, etc. Correlation analyses revealed that TyG index was negatively correlated with the neurological status of patients post-CA.

CONCLUSION

Elevated TyG index is significantly associated with the occurrence of CA and higher mortality risk in patients post-CA. Our findings extend the landscape of TyG index in cardiovascular diseases, which requires further prospective cohort study.

Mild Hypothermia Alleviates Complement C5a-Induced Neuronal Autophagy During Brain Ischemia-Reperfusion Injury After Cardiac Arrest

After restoration of spontaneous circulation (ROSC) following cardiac arrest, complements can be activated and excessive autophagy can contribute to the brain ischemia-reperfusion (I/R) injury. Mild hypothermia (HT) protects against brain I/R injury after ROSC, but the mechanisms have not been fully elucidated. Here, we found that HT significantly inhibited the increases in serum NSE, S100β, and C5a, as well as neurologic deficit scores, TUNEL-positive cells, and autophagic vacuoles in the pig brain cortex after ROSC. The C5a receptor 1 (C5aR1) mRNA and the C5a, C5aR1, Beclin 1, LC3-II, and cleaved caspase-3 proteins were significantly increased, but the P62 protein and the PI3K/Akt/mTOR pathway-related proteins were significantly reduced in pigs after ROSC or neuronal oxygen-glucose deprivation/reoxygenation. HT could significantly attenuate the above changes in NT-treated neurons. Furthermore, C5a treatment induced autophagy and apoptosis and reduced the PI3K/Akt/mTOR pathway-related proteins in cultured neurons, which could be reversed by C5aR1 antagonist PMX205. Our findings demonstrated that C5a could bind to C5aR1 to induce neuronal autophagy during the brain I/R injury, which was associated with the inhibited PI3K/Akt/mTOR pathway. HT could inhibit C5a-induced neuronal autophagy by regulating the C5a-C5aR1 interaction and the PI3K/Akt/mTOR pathway, which might be one of the neuroprotective mechanisms underlying I/R injury. The C5a receptor 1 (C5aR1) mRNA and the C5a, C5aR1, Beclin 1, LC3-II, and cleaved caspase-3 proteins were significantly increased, but the P62 protein and the PI3K/Akt/mTOR pathway-related proteins were significantly reduced in pigs after ROSC or neuronal oxygen-glucose deprivation/reoxygenation. Mild hypothermia (HT) could significantly attenuate the above changes in NT-treated neurons. Furthermore, C5a treatment induced autophagy and apoptosis and reduced the PI3K/Akt/mTOR pathway-related proteins in cultured neurons, which could be reversed by C5aR1 antagonist PMX205. Proposed mechanism by which HT protects against brain I/R injury by repressing C5a-C5aR1-induced excessive autophagy. Complement activation in response to brain I/R injury generates C5a that can interact with C5aR1 to inactivate mTOR, probably through the PI3K-AKT pathway, which can finally lead to autophagy activation. The excessively activated autophagy ultimately contributes to cell apoptosis and brain injury. HT may alleviate complement activation and then reduce C5a-induced autophagy to protect against brain I/R injury. HT, mild hypothermia; I/R, ischemia reperfusion.

Recent developments and controversies in therapeutic hypothermia after cardiopulmonary resuscitation

Therapeutic hypothermia was recommended as the only neuroprotective treatment in comatose patients after return of spontaneous circulation (ROSC). With new evidence suggesting a similar neuroprotective effect of 36 °C and 33 °C, the term "therapeutic hypothermia" was substituted by "targeted temperature management" in 2011, which in turn was replaced by the term "temperature control" in 2022 because of new evidence of the similar effects of target normothermia and 33 °C. However, there is no clear consensus on the efficacy of therapeutic hypothermia. In this article, we provide an overview of the recent evidence from basic and clinical research related to therapeutic hypothermia and re-evaluate its application as a post-ROSC neuroprotective intervention in clinical settings.

The neuro-prognostic value of the ion shift index in cardiac arrest patients following extracorporeal cardiopulmonary resuscitation

BACKGROUND

The ion shift index (ISI) as a prognostic indicator that can show the severity of hypoxic-ischemic injury. We aimed to evaluate the performance of the ISI in predicting unfavorable neurological outcomes at hospital discharge in cardiac arrest (CA) patients following extracorporeal cardiopulmonary resuscitation (ECPR) and to compare its performance to other prognostic predictors.

METHODS

This was a retrospective observational study including adult CA patients treated with ECPR between January 2018 and December 2022 in a tertiary hospital. Data regarding clinical characteristics and laboratory parameters were collected from medical records. The ISI was determined based on the first available serum electrolyte levels after ECPR. The primary outcome was unfavorable neurological status at hospital discharge, defined as Cerebral Performance Categories 3-5. Comparisons of the characteristics between the two groups were made using the χ2 test for categorical variables and the t-test or non-parametric Mann-Whitney U-test for continuous variables, as appropriate. Correlation analysis was performed using Spearman's rank correlation coefficient. A two-tailed P-value <0.05 was considered statistically significant.

RESULTS

Among the 122 patients involved, 46 (37.7%) had out-of-hospital CA, and 88 had unfavorable neurological outcomes. The ISI was significantly higher in the unfavorable outcome group than in the favorable outcome group (3.74 [3.15-4.57] vs. 2.69 [2.51-3.07], P<0.001). A higher ISI level was independently related to unfavorable outcome (odds ratio=6.529, 95% confidence interval 2.239-19.044, P=0.001). An ISI level >3.12 predicted unfavorable outcomes with a sensitivity and specificity of 74.6% and 85.2%, respectively (P<0.001). The prognostic performance of ISI (area under the curve [AUC]=0.887) was similar to that of other predictors, such as gray-to-white matter ratio (AUC=0.850, P=0.433) and neuron-specific enolase (AUC=0.925, P=0.394).

CONCLUSION

ISI may be used as a prognostic biomarker to predict neurological outcomes in CA patients following ECPR.

Through the Looking Glass: The Paradoxical Evolution of Targeted Temperature Management for Comatose Survivors of Cardiac Arrest

For the past two decades, targeted temperature management (TTM) has been a staple in the care of comatose survivors following cardiac arrest. However, recent clinical trials have failed to replicate the benefit seen in earlier studies, bringing into question the very existence of such clinical practice. In this review, we explore clinical scenarios within critical care that appeared to share a similar fate, but in actuality changed the landscape of practice in a modern world. Accordingly, clinicians may apply these lessons to the utilization of TTM among comatose survivors following cardiac arrest, potentially paving way for a re-framing of clinical care amidst an environment where current data appears upside down in comparison to past successes.

Identification and Validation of Novel Potential Pathogenesis and Biomarkers to Predict the Neurological Outcome after Cardiac Arrest

Predicting neurological outcomes after cardiac arrest remains a major issue. This study aimed to identify novel biomarkers capable of predicting neurological prognosis after cardiac arrest. Expression profiles of GSE29540 and GSE92696 were downloaded from the Gene Expression Omnibus (GEO) database to obtain differentially expressed genes (DEGs) between high and low brain performance category (CPC) scoring subgroups. Weighted gene co-expression network analysis (WGCNA) was used to screen key gene modules and crossover genes in these datasets. The protein-protein interaction (PPI) network of crossover genes was constructed from the STRING database. Based on the PPI network, the most important hub genes were identified by the cytoHubba plugin of Cytoscape software. Eight hub genes (RPL27, EEF1B2, PFDN5, RBX1, PSMD14, HINT1, SNRPD2, and RPL26) were finally screened and validated, which were downregulated in the group with poor neurological prognosis. In addition, GSEA identified critical pathways associated with these genes. Finally, a Pearson correlation analysis showed that the mRNA expression of hub genes EEF1B2, PSMD14, RPFDN5, RBX1, and SNRPD2 were significantly and positively correlated with NDS scores in rats. Our work could provide comprehensive insights into understanding pathogenesis and potential new biomarkers for predicting neurological outcomes after cardiac arrest.