Predicting Outcome With Diffusion-Weighted Imaging in Cardiac Arrest Patients Receiving Hypothermia Therapy: Multicenter Retrospective Cohort Study

A practical magnetic-resonance imaging score for outcome prediction in comatose cardiac arrest survivors

AIM

Magnetic Resonance Imaging (MRI) is an important prognostic tool in cardiac arrest (CA) survivors given its sensitivity for detecting hypoxic-ischemic brain injury (HIBI), however, it is limited by poorly defined objective thresholds. To address this limitation, we evaluated a qualitative MRI score for predicting neurological outcome in CA survivors.

METHODS

Adult comatose CA survivors who underwent MRI were retrospectively identified at a single academic medical center. Two blinded neurointensivists qualitatively scored HIBI amongst 12 MRI brain regions. Scores were summated to form four distinct score groups: cortex, deep grey nuclei (DGN), cortex-DGN combined, and total (cortex, DGN, brainstem, and cerebellum). Poor neurological outcome was defined as Cerebral Performance Category (CPC) score 3-5 at hospital discharge. Inter-rater reliability was tested using intra-class correlation (ICC) and discrimination of poor neurological outcome assessed using area under the receiver operating curve (AUC).

RESULTS

Our cohort included 219 patients with median time to MRI of 96 (IQR 81-110) hours. ICC (95% CI) was good to excellent across all MRI scores: cortex 0.92 (0.89-0.94), DGN 0.88 (0.80-0.92), cortex-DGN 0.94 (0.92-0.95), and total 0.93 (0.91-0.95). AUC (95% CI) for poor outcome was good across all MRI scores: cortex 0.84 (0.78-0.90), DGN 0.83 (0.77-0.89), cortex-DGN 0.83 (0.77-0.89), and total 0.83 (0.77-0.88).

CONCLUSION

A simplified, qualitative MRI score had excellent reliability and good discrimination for poor neurologic outcome. Further work is necessary to externally validate our findings in an independent, ideally prospective, cohort.

Quantitative analysis of apparent diffusion coefficients to predict neurological prognosis in cardiac arrest survivors: an observational derivation and internal-external validation study

BACKGROUND

This study aimed to validate apparent diffusion coefficient (ADC) values and thresholds to predict poor neurological outcomes in out-of-hospital cardiac arrest (OHCA) survivors by quantitatively analysing the ADC values via brain magnetic resonance imaging (MRI).

METHODS

This observational study used prospectively collected data from two tertiary academic hospitals. The derivation cohort comprised 70% of the patients randomly selected from one hospital, whereas the internal validation cohort comprised the remaining 30%. The external validation cohort used the data from another hospital, and the MRI data were restricted to scans conducted at 3 T within 72-96 h after an OHCA experience. We analysed the percentage of brain volume below a specific ADC value at 50-step intervals ranging from 200 to 1200 × 10-6 mm2/s, identifying thresholds that differentiate between good and poor outcomes. Poor neurological outcomes were defined as cerebral performance categories 3-5, 6 months after experiencing an OHCA.

RESULTS

A total of 448 brain MRI scans were evaluated, including a derivation cohort (n = 224) and internal/external validation cohorts (n = 96/128, respectively). The proportion of brain volume with ADC values below 450, 500, 550, 600, and 650 × 10-6 mm2/s demonstrated good to excellent performance in predicting poor neurological outcomes in the derivation group (area under the curve [AUC] 0.89-0.91), and there were no statistically significant differences in performances among the derivation, internal validation, and external validation groups (all P > 0.5). Among these, the proportion of brain volume with an ADC below 600 × 10-6 mm2/s predicted a poor outcome with a 0% false-positive rate (FPR) and 76% (95% confidence interval [CI] 68-83) sensitivity at a threshold of > 13.2% in the derivation cohort. In both the internal and external validation cohorts, when using the same threshold, a specificity of 100% corresponded to sensitivities of 71% (95% CI 58-81) and 78% (95% CI 66-87), respectively.

CONCLUSIONS

In this validation study, by consistently restricting the MRI types and timing during quantitative analysis of ADC values in brain MRI, we observed high reproducibility and sensitivity at a 0% FPR. Prospective multicentre studies are necessary to validate these findings.

Prognostic Performance of Initial Clinical Examination in Predicting Good Neurological Outcome in Cardiac Arrest Patients Treated with Targeted Temperature Management

Prognostication studies of cardiac arrest patients have mainly focused on poor neurological outcomes. However, an optimistic prognosis for good outcome could provide both justification to maintain and escalate treatment and evidence-based support to persuade family members or legal surrogates after cardiac arrest. The aim of the study was to evaluate the utility of clinical examinations performed after return of spontaneous circulation (ROSC) in predicting good neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM). This retrospective study included OHCA patients treated with TTM from 2009 to 2021. Initial clinical examination findings related to the Glasgow coma scale (GCS) motor score, pupillary light reflex, corneal reflex (CR) and breathing above the set ventilator rate were assessed immediately after ROSC and before the initiation of TTM. The primary outcome was good neurological outcome at 6 months after cardiac arrest. Of 350 patients included in the analysis, 119 (34%) experienced a good neurological outcome at 6 months after cardiac arrest. Among the parameters of the initial clinical examinations, specificity was the highest for the GCS motor score, and sensitivity was the highest for breathing above the set ventilator rate. A GCS motor score of >2 had a sensitivity of 42.0% (95% confidence interval [CI] = 33.0-51.4) and a specificity of 96.5% (95% CI = 93.3-98.5). Breathing above the set ventilator rate had a sensitivity of 84.0% (95% CI = 76.2-90.1) and a specificity of 69.7% (95% CI = 63.3-75.6). As the number of positive responses increased, the proportion of patients with good outcomes increased. Consequently, 87.0% of patients for whom all four examinations were positive experienced good outcomes. As a result, the initial clinical examinations predicted good neurological outcomes with a sensitivity of 42.0-84.0% and a specificity of 69.7-96.5%. When more examinations with positive results are achieved, a good neurological outcome can be expected.

Combination strategy for prognostication in patients undergoing post-resuscitation care after cardiac arrest

This study investigated the prognostic performance of combination strategies using a multimodal approach in patients treated after cardiac arrest. Prospectively collected registry data were used for this retrospective analysis. Poor outcome was defined as a cerebral performance category of 3-5 at 6 months. Predictors of poor outcome were absence of ocular reflexes (PR/CR) without confounding factors, a highly malignant pattern on the most recent electroencephalography, defined as suppressed background with or without periodic discharges and burst-suppression, high neuron-specific enolase (NSE) after 48 h, and diffuse injury on imaging studies (computed tomography or diffusion-weighted imaging [DWI]) at 72-96 h. The prognostic performances for poor outcomes were analyzed for sensitivity and specificity. A total of 130 patients were included in the analysis. Of these, 68 (52.3%) patients had poor outcomes. The best prognostic performance was observed with the combination of absent PR/CR, high NSE, and diffuse injury on DWI [91.2%, 95% confidence interval (CI) 80.7-97.1], whereas the combination strategy of all available predictors did not improve prognostic performance (87.8%, 95% CI 73.8-95.9). Combining three of the predictors may improve prognostic performance and be more efficient than adding all tests indiscriminately, given limited medical resources.

Prognosis of Cardiac Arrest-Peri-arrest and Post-arrest Considerations

There has been only a small improvement in survival and neurologic outcomes in patients with cardiac arrest in recent decades. Type of arrest, length of total arrest time, and location of arrest alter the trajectory of survival and neurologic outcome. In the post-arrest phase, clinical markers such as blood markers, pupillary light response, corneal reflex, myoclonic jerking, somatosensory evoked potential, and electroencephalography testing can be used to help guide neurological prognostication. Most of the testing should be performed 72 hours post-arrest with special considerations for longer observation periods in patients who underwent TTM or who had prolonged sedation and/or neuromuscular blockade.

Association between the extent of diffusion restriction on brain diffusion-weighted imaging and neurological outcomes after an out-of-hospital cardiac arrest

BACKGROUND

This study evaluated the association between the extent of diffusion restriction on brain diffusion-weighted imaging (DWI) and neurological outcomes in patients who underwent targeted temperature management (TTM) after an out-of-hospital cardiac arrest (OHCA).

METHODS

Patients who underwent brain magnetic resonance imaging within 10 days of OHCA between 2012 and 2021 were analysed. The extent of diffusion restriction was described according to the modified DWI Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS). The 35 predefined brain regions were assigned a score if diffuse signal changes were concordantly present in DWI scans and apparent diffusion coefficient maps. The primary outcome was an unfavourable neurological outcome at 6 months. The sensitivity, specificity, and receiver operating characteristic (ROC) curves for the measured parameters were analysed. Cut-off values were determined to predict the primary outcome. The predictive cut-off DWI-ASPECTS was internally validated using five-fold cross-validation.

RESULTS

Of the 301 patients, 108 (35.9%) had 6-month favourable neurological outcomes. Patients with unfavourable outcomes had higher whole-brain DWI-ASPECTS (median, 31 [26-33] vs. 0 [0-1], P < 0.001) than those with favourable outcomes. The area under the ROC curve (AUROC) of whole-brain DWI-ASPECTS was 0.957 (95% confidence interval [CI] 0.928-0.977). A cut-off value of ≥8 for unfavourable neurological outcomes had specificity and sensitivity of 100% (95% CI 96.6-100) and 89.6% (95% CI 84.4-93.6), respectively. The mean AUROC was 0.956.

CONCLUSION

More extensive diffusion restriction on DWI-ASPECTS in patients with OHCA who underwent TTM was associated with 6-month unfavourable neurological outcomes. Running title: Diffusion restriction and neurological outcomes after cardiac arrest.

Parieto-Occipital Injury on Diffusion MRI Correlates with Poor Neurologic Outcome following Cardiac Arrest

BACKGROUND AND PURPOSE

MR imaging of the brain provides unbiased neuroanatomic evaluation of brain injury and is useful for neurologic prognostication following cardiac arrest. Regional analysis of diffusion imaging may provide additional prognostic value and help reveal the neuroanatomic underpinnings of coma recovery. The purpose of this study was to evaluate global, regional, and voxelwise differences in diffusion-weighted MR imaging signal in patients in a coma after cardiac arrest.

MATERIALS AND METHODS

We retrospectively analyzed diffusion MR imaging data from 81 subjects who were comatose for >48 hours following cardiac arrest. Poor outcome was defined as the inability to follow simple commands at any point during hospitalization. ADC differences between groups were evaluated across the whole brain, locally by using voxelwise analysis and regionally by using ROI-based principal component analysis.

RESULTS

Subjects with poor outcome had more severe brain injury as measured by lower average whole-brain ADC (740 [SD, 102] × 10-6 mm2/s versus 833 [SD, 23] × 10-6 mm2/s, P < .001) and larger average volumes of tissue with ADC below 650 × 10-6 mms/s (464 [SD, 469] mL versus 62 [SD, 51] mL, P < .001). Voxelwise analysis showed lower ADC in the bilateral parieto-occipital areas and perirolandic cortices for the poor outcome group. ROI-based principal component analysis showed an association between lower ADC in parieto-occipital regions and poor outcome.

CONCLUSIONS

Brain injury affecting the parieto-occipital region measured with quantitative ADC analysis was associated with poor outcomes after cardiac arrest. These results suggest that injury to specific brain regions may influence coma recovery.

Circular RNAs to predict clinical outcome after cardiac arrest

Background

Cardiac arrest (CA) represents the third leading cause of death worldwide. Among patients resuscitated and admitted to hospital, death and severe neurological sequelae are frequent but difficult to predict. Blood biomarkers offer clinicians the potential to improve prognostication. Previous studies suggest that circulating non-coding RNAs constitute a reservoir of novel biomarkers. Therefore, this study aims to identify circulating circular RNAs (circRNAs) associated with clinical outcome after CA.

Results

Whole blood samples obtained 48 h after return of spontaneous circulation in 588 survivors from CA enrolled in the Target Temperature Management trial (TTM) were used in this study. Whole transcriptome RNA sequencing in 2 groups of 23 sex-matched patients identified 28 circRNAs associated with neurological outcome and survival. The circRNA circNFAT5 was selected for further analysis using quantitative PCR. In the TTM-trial (n = 542), circNFAT5 was upregulated in patients with poor outcome as compared to patients with good neurological outcome (p < 0.001). This increase was independent of TTM regimen and sex. The adjusted odds ratio of circNFAT5 to predict neurological outcome was 1.39 [1.07–1.83] (OR [95% confidence interval]). CircNFAT5 predicted 6-month survival with an adjusted hazard ratio of 1.31 [1.13–1.52].

Conclusion

We identified circulating circRNAs associated with clinical outcome after CA, among which circNFAT5 may have potential to aid in predicting neurological outcome and survival when used in combination with established biomarkers of CA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40635-022-00470-7.

Prognostic accuracy of head computed tomography for prediction of functional outcome after out-of-hospital cardiac arrest: Rationale and design of the prospective TTM2-CT-substudy

Background

Head computed tomography (CT) is a guideline recommended method to predict functional outcome after cardiac arrest (CA), but standardized criteria for evaluation are lacking. To date, no prospective trial has systematically validated methods for diagnosing hypoxic-ischaemic encephalopathy (HIE) on CT after CA. We present a protocol for validation of pre-specified radiological criteria for assessment of HIE on CT for neuroprognostication after CA.

Methods/design

This is a prospective observational international multicentre substudy of the Targeted Hypothermia versus Targeted Normothermia after out-of-hospital cardiac arrest (TTM2) trial. Patients still unconscious 48 hours post-arrest at 13 participating hospitals were routinely examined with CT. Original images will be evaluated by examiners blinded to clinical data using a standardized protocol. Qualitative assessment will include evaluation of absence/presence of "severe HIE". Radiodensities will be quantified in pre-specified regions of interest for calculation of grey-white matter ratios (GWR) at the basal ganglia level. Functional outcome will be dichotomized into good (modified Rankin Scale 0-3) and poor (modified Rankin Scale 4-6) at six months post-arrest. Prognostic accuracies for good and poor outcome will be presented as sensitivities and specificities with 95% confidence intervals (using pre-specified cut-offs for quantitative analysis), descriptive statistics (Area Under the Receiver Operating Characteristics Curve), inter- and intra-rater reliabilities according to STARD guidelines.

Conclusions

The results from this prospective trial will validate a standardized approach to radiological evaluations of HIE on CT for prediction of functional outcome in comatose CA patients.The TTM2 trial and the TTM2 CT substudy are registered at ClinicalTrials.gov NCT02908308 and NCT03913065.

A red flag for diagnosing brain death: decompressive craniectomy of the posterior fossa

PURPOSE

Brain death/death by neurologic criteria (BD/DNC) may be determined in many countries by a clinical examination that shows coma, brainstem areflexia, and apnea, provided the conditions causing reversible loss of brain function are excluded a priori. To date, accounts of recovery from BD/DNC in adults have been limited to noncompliance with guidelines.

CLINICAL FEATURES

We report the case of a 72-yr-old man with a combined primary infratentorial (hemorrhagic) and secondary global (anoxic) brain lesion in whom decompressive craniectomy of the posterior fossa and six-hour therapeutic hypothermia (33-34°C) followed by 8-hour rewarming to ≥ 36°C were conducted. Thirteen hours later, clinical findings of brain function loss were documented in addition to guideline-compliant exclusion of reversible causes (arterial hypotension, intoxication, depressant drug effects, relevant metabolic or endocrine disequilibrium, chronic hypercapnia, neuromuscular disorders, and administration of a muscle relaxant). Since a primary infratentorial brain lesion was present, German guidelines required further ancillary testing. Doppler ultrasonography revealed some preserved cerebral circulation, and BD/DNC was not diagnosed. Approximately 24 hr after rewarming to ≥ 36°C, the patient exhibited respiratory efforts. He continued with assisted respiration until final asystole/apnea, without regaining additional brain function other than mild signs of hemispasticity. Follow-up computed tomography showed partial herniation of the cerebellum through the craniectomy gap of the posterior fossa, alleviating caudal brain stem compression.

CONCLUSIONS

Therapeutic decompressive craniectomy of the posterior fossa may allow for delayed reversal of apnea. In these patients, proof of cerebral circulatory arrest should be mandatory for diagnosing BD/DNC.

Bedside monitoring of hypoxic ischemic brain injury using low-field, portable brain magnetic resonance imaging after cardiac arrest

BACKGROUND

Assessment of brain injury severity is critically important after survival from cardiac arrest (CA). Recent advances in low-field MRI technology have permitted the acquisition of clinically useful bedside brain imaging. Our objective was to deploy a novel approach for evaluating brain injury after CA in critically ill patients at high risk for adverse neurological outcome.

METHODS

This retrospective, single center study involved review of all consecutive portable MRIs performed as part of clinical care for CA patients between September 2020 and January 2022. Portable MR images were retrospectively reviewed by a blinded board-certified neuroradiologist (S.P.). Fluid-inversion recovery (FLAIR) signal intensities were measured in select regions of interest.

RESULTS

We performed 22 low-field MRI examinations in 19 patients resuscitated from CA (68.4% male, mean [standard deviation] age, 51.8 [13.1] years). Twelve patients (63.2%) had findings consistent with HIBI on conventional neuroimaging radiology report. Low-field MRI detected findings consistent with HIBI in all of these patients. Low-field MRI was acquired at a median (interquartile range) of 78 (40-136) hours post-arrest. Quantitatively, we measured FLAIR signal intensity in three regions of interest, which were higher amongst patients with confirmed HIBI. Low-field MRI was completed in all patients without disruption of intensive care unit equipment monitoring and no safety events occurred.

CONCLUSION

In a critically ill CA population in whom MR imaging is often not feasible, low-field MRI can be deployed at the bedside to identify HIBI. Low-field MRI provides an opportunity to evaluate the time-dependent nature of MRI findings in CA survivors.

External validation of the 2020 ERC/ESICM prognostication strategy algorithm after cardiac arrest

Purpose

To assess the performance of the post-cardiac arrest (CA) prognostication strategy algorithm recommended by the European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) in 2020.

Methods

This was a retrospective analysis of the Korean Hypothermia Network Prospective Registry 1.0. Unconscious patients without confounders at day 4 (72–96 h) after return of spontaneous circulation (ROSC) were included. The association between the prognostic factors included in the prognostication strategy algorithm, except status myoclonus and the neurological outcome, was investigated, and finally, the prognostic performance of the prognostication strategy algorithm was evaluated. Poor outcome was defined as cerebral performance categories 3–5 at 6 months after ROSC.

Results

A total of 660 patients were included in the final analysis. Of those, 108 (16.4%) patients had a good neurological outcome at 6 months after CA. The 2020 ERC/ESICM prognostication strategy algorithm identified patients with poor neurological outcome with 60.2% sensitivity (95% CI 55.9–64.4) and 100% specificity (95% CI 93.9–100) among patients who were unconscious or had a GCS_M score ≤ 3 and with 58.2% sensitivity (95% CI 53.9–62.3) and 100% specificity (95% CI 96.6–100) among unconscious patients. When two prognostic factors were combined, any combination of prognostic factors had a false positive rate (FPR) of 0 (95% CI 0–5.6 for combination of no PR/CR and poor CT, 0–30.8 for combination of No SSEP N20 and NSE 60).

Conclusion

The 2020 ERC/ESICM prognostication strategy algorithm predicted poor outcome without an FPR and with sensitivities of 58.2–60.2%. Any combinations of two predictors recommended by ERC/ESICM showed 0% of FPR.

Neuroprognostic Accuracy of Quantitative Versus Standard Pupillary Light Reflex for Adult Postcardiac Arrest Patients: A Systematic Review and Meta-Analysis

OBJECTIVES

An automated infrared pupillometer measures quantitative pupillary light reflex using a calibrated light stimulus. We examined whether the timing of performing quantitative pupillary light reflex or standard pupillary light reflex may impact its neuroprognostic performance in postcardiac arrest comatose patients and whether quantitative pupillary light reflex may outperform standard pupillary light reflex in early postresuscitation phase.

DATA SOURCES

PubMed and Embase databases from their inception to July 2020.

STUDY SELECTION

We selected studies providing sufficient data of prognostic values of standard pupillary light reflex or quantitative pupillary light reflex to predict neurologic outcomes in adult postcardiac arrest comatose patients.

DATA EXTRACTION

Quantitative data required for building a 2 × 2 contingency table were extracted, and study quality was assessed using standard criteria.

DATA SYNTHESIS

We used the bivariate random-effects model to estimate the pooled sensitivity and specificity of standard pupillary light reflex or quantitative pupillary light reflex in predicting poor neurologic outcome during early (< 72 hr), middle (between 72 and 144 hr), and late (≧ 145 hr) postresuscitation periods, respectively. We included 39 studies involving 17,179 patients. For quantitative pupillary light reflex, the cut off points used in included studies to define absent pupillary light reflex ranged from 0% to 13% (median: 7%) and from zero to 2 (median: 2) for pupillary light reflex amplitude and Neurologic Pupil index, respectively. Late standard pupillary light reflex had the highest area under the receiver operating characteristic curve (0.98, 95% CI [CI], 0.97-0.99). For early standard pupillary light reflex, the area under the receiver operating characteristic curve was 0.80 (95% CI, 0.76-0.83), with a specificity of 0.91 (95% CI, 0.85-0.95). For early quantitative pupillary light reflex, the area under the receiver operating characteristic curve was 0.83 (95% CI, 0.79-0.86), with a specificity of 0.99 (95% CI, 0.91-1.00).

CONCLUSIONS

Timing of pupillary light reflex examination may impact neuroprognostic accuracy. The highest prognostic performance was achieved with late standard pupillary light reflex. Early quantitative pupillary light reflex had a similar specificity to late standard pupillary light reflex and had better specificity than early standard pupillary light reflex. For postresuscitation comatose patients, early quantitative pupillary light reflex may substitute for early standard pupillary light reflex in the neurologic prognostication algorithm.

Quantitative magnetic resonance imaging assessment of brain injury after successful cardiopulmonary resuscitation in a rat model of asphyxia cardiac arrest

The aim of this study was to use dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted magnetic resonance imaging (DWI) to measure changes in blood-brain barrier (BBB) permeability and cerebral edema over time in a rat model of asphyxial cardiac arrest (ACA). ACA was established by endotracheal tube clamping. Male rats were randomized into a sham group (n = 5) and three ACA groups (n = 18). After return of spontaneous circulation (ROSC), the rats were randomized to perform DWI and DCE-MRI exam in the 6 h, 24 h and 72 h timepoint (ROSC + 6 h, ROSC + 24 h, and ROSC + 72 h). Results shows that fifteen of 18 animals achieved successful resuscitation in the ACA groups. The average apparent diffusion coefficient(ADC) value of the whole brain in ROSC + 6 h was markedly lower than those of the sham, ROSC + 24 h, and ROSC + 72 h. The aquaporin-4(AQP4) score in ROSC + 6 h was significantly higher than those in the other groups, which were negatively correlated with the ADC values. The ratio of whole brain to masseter muscle of volume transfer constant (rK^trans), tissue interstitium-to-plasma rate constant(rK_ep), and fractional extra-cellular space volume(rV_e) in ROSC + 6 h were all significantly higher than those in the sham, ROSC + 24 h, and ROSC + 72 h. The transforming growth factor β1(TGF-β1) and vascular endothelial growth factor A(VEGF-a) scores in ROSC + 6 h were significantly higher than those in the other groups, which were all positively correlated with rK^trans and rK_ep. In conclusions, brain injury is a frequent complication after CA and resuscitation. DWI and DCE-MRI can quantitatively evaluate brain injury in term of cerebral edema and BBB permeability after successful CPR.

Added Value of Quantitative Apparent Diffusion Coefficient Values for Neuroprognostication After Cardiac Arrest

OBJECTIVE

To test the prognostic value of brain MRI in addition to clinical and electrophysiologic variables in patients post-cardiac arrest (CA), we explored data from the randomized Neuroprotect Post-CA trial (NCT02541591).

METHODS

In this trial, brain MRIs were prospectively obtained. We calculated receiver operating characteristic (ROC) curves for the average apparent diffusion coefficient (ADC) value and percentage of brain voxels with an ADC value <650 × 10^-6 mm²/s and <450 × 10^-6 mm²/s. We constructed multivariable logistic regression models with clinical characteristics, EEG, somatosensory evoked potentials (SSEP), and ADC value as independent variables to predict good neurologic recovery.

RESULTS

In 79/102 patients, MRI data were available and in 58/79 patients all other data were available. At 180 days post-CA, 25/58 (43%) patients had good neurologic recovery. In univariable analysis of all tested MRI measures, average ADC value in the postcentral cortex had the highest accuracy to predict good neurologic recovery, with an area under the ROC curve (AUC) of 0.78. In the most optimal multivariable model, which also included corneal reflexes and EEG, this measure remained an independent predictor of good neurologic recovery (AUC 0.96, false-positive 27%). This model provided a more accurate prediction compared to the most optimal combination of EEG, corneal reflexes, and SSEP (p = 0.03).

CONCLUSIONS

Adding information on brain MRI in a multivariable model may improve the prediction of good neurologic recovery in patients post-CA.

CLASSIFICATION OF EVIDENCE

This study provides Class III evidence that MRI ADC features predict neurologic recovery in patients post-CA.

European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation and organ donation.

European Resuscitation Council and European Society of Intensive Care Medicine Guidelines 2021: Post-resuscitation care

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation, and organ donation.

Cardiac Magnetic Resonance Imaging for Nonischemic Cardiac Disease in Out-of-Hospital Cardiac Arrest Survivors Treated with Targeted Temperature Management: A Multicenter Retrospective Analysis

(1) Background: Cardiac magnetic resonance (CMR) imaging is an emerging tool for investigating nonischemic cardiomyopathies and cardiac systemic disease. However, data on the cardiac arrest population are limited. This study aimed to evaluate the usefulness of CMR imaging in out-of-hospital cardiac arrest (OHCA) survivors treated with targeted temperature management (TTM). (2) Methods: We conducted the retrospective observational study using a multicenter registry of adult non-traumatic comatose OHCA survivors who underwent TTM between January 2010 and December 2019. Of the 949 patients, 389 with OHCA of non-cardiac cause, 145 with significant lesions in the coronary artery, 151 who died during TTM, 81 without further evaluation due to anticipated poor neurological outcome, and 51 whose etiology is underlying disease were excluded. In 36 of the 132 remaining patients, the etiologies included variant angina, long QT syndrome, and complete atrioventricular block in ancillary studies. Fifty-six patients were diagnosed idiopathic ventricular fibrillation without CMR. (3) Results: CMR imaging was performed in the remaining 40 patients with cardiac arrest of unknown cause. The median time from cardiac arrest to CMR imaging was 10.1 days. The CMR finding was normal in 23 patients, non-diagnostic in 12, and abnormal in 5, which suggested non-ischemic cardiomyopathy but did not support the final diagnosis. (4) Conclusions: CMR imaging may not be useful for identifying unknown causes of cardiac arrest in OHCA survivors treated with targeted temperature management without definitive diagnosis even after coronary angiography, echocardiography, and electrophysiology studies. However, further large-scale studies will be needed to confirm these findings.

Is two-dimensional echocardiography better than electrocardiography for predicting patient outcomes after cardiac arrest?

BACKGROUND

Coronary artery stenosis increases hospital mortality and leads to poor neurological recovery in cardiac arrest (CA) patients. However, electrocardiography (ECG) cannot fully predict the presence of coronary artery stenosis in CA patients. Hence, we aimed to determine whether regional wall motion abnormality (RWMA), as observed by two-dimensional echocardiography (2DE), predicted patient survival outcomes with greater accuracy than did ST segment elevation (STE) on ECG in CA patients who underwent coronary angiography (CAG) after return of spontaneous circulation.

METHODS

This was a retrospective observational study of adult patients with CA of presumed cardiac etiology who underwent CAG at a single tertiary care hospital. We investigated whether RWMA observed on 2DE predicted patient outcomes more accurately than did STE observed on ECG. The primary outcome was incidence of hospital mortality. The secondary outcomes were Glasgow-Pittsburgh Cerebral Performance Category scores measured 6 months after discharge and significant coronary artery stenosis on CAG.

RESULTS

Among the 145 patients, 36 (24.8%) experienced in-hospital death. In multivariable analysis of survival outcomes, only total arrest time (P=0.011) and STE (P=0.035) were significant. The odds ratio (OR) and 95% confidence interval (CI), which were obtained by adjusting the total arrest time for survival outcomes, were significant only for STE (OR, 0.40; 95% CI, 0.17-0.94). The presence of RWMA was not a significant factor.

CONCLUSIONS

While STE predicted survival outcomes in adult CA patients, RWMA did not. The decision to perform CAG after CA should include ECG under existing guidelines. The use of RWMA has limited benefits in treatment of this population.

Adult Advanced Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science with Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations for advanced life support includes updates on multiple advanced life support topics addressed with 3 different types of reviews. Topics were prioritized on the basis of both recent interest within the resuscitation community and the amount of new evidence available since any previous review. Systematic reviews addressed higher-priority topics, and included double-sequential defibrillation, intravenous versus intraosseous route for drug administration during cardiac arrest, point-of-care echocardiography for intra-arrest prognostication, cardiac arrest caused by pulmonary embolism, postresuscitation oxygenation and ventilation, prophylactic antibiotics after resuscitation, postresuscitation seizure prophylaxis and treatment, and neuroprognostication. New or updated treatment recommendations on these topics are presented. Scoping reviews were conducted for anticipatory charging and monitoring of physiological parameters during cardiopulmonary resuscitation. Topics for which systematic reviews and new Consensuses on Science With Treatment Recommendations were completed since 2015 are also summarized here. All remaining topics reviewed were addressed with evidence updates to identify any new evidence and to help determine which topics should be the highest priority for systematic reviews in the next 1 to 2 years.

Adult Advanced Life Support: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

This 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations for advanced life support includes updates on multiple advanced life support topics addressed with 3 different types of reviews. Topics were prioritized on the basis of both recent interest within the resuscitation community and the amount of new evidence available since any previous review. Systematic reviews addressed higher-priority topics, and included double-sequential defibrillation, intravenous versus intraosseous route for drug administration during cardiac arrest, point-of-care echocardiography for intra-arrest prognostication, cardiac arrest caused by pulmonary embolism, postresuscitation oxygenation and ventilation, prophylactic antibiotics after resuscitation, postresuscitation seizure prophylaxis and treatment, and neuroprognostication. New or updated treatment recommendations on these topics are presented. Scoping reviews were conducted for anticipatory charging and monitoring of physiological parameters during cardiopulmonary resuscitation. Topics for which systematic reviews and new Consensuses on Science With Treatment Recommendations were completed since 2015 are also summarized here. All remaining topics reviewed were addressed with evidence updates to identify any new evidence and to help determine which topics should be the highest priority for systematic reviews in the next 1 to 2 years.

Prediction of poor neurological outcome in comatose survivors of cardiac arrest: a systematic review

Purpose

To assess the ability of clinical examination, blood biomarkers, electrophysiology, or neuroimaging assessed within 7 days from return of spontaneous circulation (ROSC) to predict poor neurological outcome, defined as death, vegetative state, or severe disability (CPC 3–5) at hospital discharge/1 month or later, in comatose adult survivors from cardiac arrest (CA).

Methods

PubMed, EMBASE, Web of Science, and the Cochrane Database of Systematic Reviews (January 2013–April 2020) were searched. Sensitivity and false-positive rate (FPR) for each predictor were calculated. Due to heterogeneities in recording times, predictor thresholds, and definition of some predictors, meta-analysis was not performed.

Results

Ninety-four studies (30,200 patients) were included. Bilaterally absent pupillary or corneal reflexes after day 4 from ROSC, high blood values of neuron-specific enolase from 24 h after ROSC, absent N20 waves of short-latency somatosensory-evoked potentials (SSEPs) or unequivocal seizures on electroencephalogram (EEG) from the day of ROSC, EEG background suppression or burst-suppression from 24 h after ROSC, diffuse cerebral oedema on brain CT from 2 h after ROSC, or reduced diffusion on brain MRI at 2–5 days after ROSC had 0% FPR for poor outcome in most studies. Risk of bias assessed using the QUIPS tool was high for all predictors.

Conclusion

In comatose resuscitated patients, clinical, biochemical, neurophysiological, and radiological tests have a potential to predict poor neurological outcome with no false-positive predictions within the first week after CA. Guidelines should consider the methodological concerns and limited sensitivity for individual modalities. (PROSPERO CRD42019141169)

Electronic supplementary material

The online version of this article (10.1007/s00134-020-06198-w) contains supplementary material, which is available to authorized users.

Cerebral Infarction Observed on Brain MRI in Unconscious Out-of-Hospital Cardiac Arrest Survivors: A Pilot Study

BACKGROUND

Cumulative evidence regarding the use of brain magnetic resonance imaging (MRI) for predicting prognosis of unconscious out-of-hospital cardiac arrest (OHCA) survivors treated with targeted temperature management (TTM) is available. Theoretically, these patients are at a high risk of developing cerebral infarction. However, there is a paucity of reports regarding the characteristics of cerebral infarction in this population. Thus, we performed a pilot study to identify the characteristics and risk factors of cerebral infarction and to evaluate whether this infarction is associated with clinical outcomes.

METHODS

A single-center, retrospective, registry-based cohort study was conducted at Severance Hospital, a tertiary center. Unconscious OHCA survivors were registered and treated with TTM between September 2011 and December 2015. We included patients who underwent brain MRI in the first week after the return of spontaneous circulation. We excluded patients who underwent any endovascular interventions to focus on "procedure-unrelated" cerebral infarctions. We assessed hypoxic-ischemic encephalopathy (HIE) and procedure-unrelated cerebral infarction separately on MRI. Patients were categorized into the following groups based on MRI findings: HIE (-)/infarction (-), infarction-only, and HIE (+) groups. Conventional vascular risk factors showing p < 0.05 in univariate analyses were entered into multivariate logistic regression. We also evaluated if the presence of this procedure-unrelated cerebral infarction lesion or HIE was associated with a poor clinical outcome at discharge, defined as a cerebral performance category of 3-5.

RESULTS

Among 71 unconscious OHCA survivors who completed TTM, underwent MRI, and who did not undergo endovascular interventions, 14 (19.7%) patients had procedure-unrelated cerebral infarction based on MRI. Advancing age [odds ratio (OR) 1.11] and atrial fibrillation (OR 5.78) were independently associated with the occurrence of procedure-unrelated cerebral infarction (both p < 0.05). There were more patients with poor clinical outcomes at discharge in the HIE (+) group (88.1%) than in the infarction-only (30.0%) or HIE (-)/infarction (-) group (15.8%) (p < 0.001). HIE (+) (OR 38.69, p < 0.001) was independently associated with poor clinical outcomes at discharge, whereas infarction-only was not (p > 0.05), compared to HIE (-)/infarction (-).

CONCLUSIONS

In this pilot study, procedure-unrelated cerebral infarction was noted in approximately one-fifth of unconscious OHCA survivors who were treated with TTM and underwent MRI. Older age and atrial fibrillation might be associated with the occurrence of procedure-unrelated cerebral infarction, and cerebral infarction was not considered to be associated with clinical outcomes at discharge. Considering that the strict exclusion criteria in this pilot study resulted in a highly selected sample with a relatively small size, further work is needed to verify our findings.

Prognostic value of magnetic resonance imaging performed during the subacute phase in adult patients with hypoxic-ischemic encephalopathy for long-term neurological outcomes

OBJECTIVE

To investigate the value of a model based on brain magnetic resonance imaging (MRI) performed in the subacute phase (between the 1st and 30th day) in predicting long-term neurological outcomes of adult hypoxic-ischemic encephalopathy (HIE) patients.

METHODS

Ninety-six adult HIE patients who underwent conventional MRI and diffusion-weighted imaging (DWI) during the subacute phase were retrospectively analyzed. Favorable (Cerebral Performance Categories (CPC) 1-2) and unfavorable outcome (CPC 3-5) groups were created based on patient neurological status approximately three months after the onset of hypoxic-ischemic events. A multivariate stepwise regression model was applied after univariate analysis of MRI findings, and then the overall MRI score, Alberta Stroke Program Early Computed Tomography Score (ASPECTS), Bilateral ASPECTS (Bi-ASPECTS), modified ASPECTS (mASPECTS) and Bi-ASPECTS combined with posterior circulation ASPECTS (PC-ASPECTS) were calculated based on MRI findings. Receiver operating characteristic (ROC) curves were used to assess prognostic accuracy.

RESULTS

Both univariate and multivariate analyses showed the cerebral cortex and cerebellum, neostriatum, hippocampus, brainstem and postanoxic leukoencephalopathy were independent prognostic factors for unfavorable outcomes. The multivariate regression analysis resulted in an overall classification accuracy of 84.4%, a sensitivity of 84.2% (95% CI, 71.6-92.1%), and a specificity of 92.3% (95% CI, 78.0-98.0%) for unfavorable outcomes. The model had an areas under the ROC curves (AUC) of 0.944 (95% CI, 0.901-0.987); the MRI overall scores were 0.918 (95% CI, 0.866, 0.971), ASPECTS 0.839 (95% CI, 0.755, 0.923), Bi-ASPECTS 0.837 (95% CI, 0.753, 0.922), mASPECTS 0.851(95% CI, 0.771, 0.931) and Bi-ASPECTS+PC-ASPECTS 0.876 (95% CI, 0.806, 0.946).

CONCLUSIONS

The multivariate model based on conventional MRI combined with DWI performed in the subacute phase could help predict the prognosis of adult HIE with high performance.

The Impact of Severity of Acute Respiratory Distress Syndrome Following Cardiac Arrest on Neurologic Outcomes

The aim of this study was to evaluate the incidence and determinants of acute respiratory distress syndrome (ARDS) after cardiac arrest (CA). We conducted an observational, retrospective cohort study with consecutive adult out-of-hospital and in-hospital (occurred only in the emergency department, ED) CA survivors from our ED. Development of ARDS was identified by results of arterial blood gases, chest images, and transthoracic echocardiography according to the Berlin definition. The primary outcome was the poor neurologic outcome, defined as cerebral performance category ≥3 at 28 days, and secondary outcomes were 28-day mortality, recovery rate from ARDS, duration of mechanical ventilator use, and length of stay. Among 295 enrolled patients, 30 patients who received extracorporeal membrane oxygenation and 19 patents who had cardiogenic pulmonary edema were excluded. ARDS had developed in 119 (48.4%) patients on admission (mild 20 [16.8%], moderate 48 [40.3%], and severe 51 [42.9%]) and 54 (45.4%) patients recovered before hospital discharge. Development of ARDS was associated with poor neurologic outcomes at 28 days (adjusted hazard ratio (HR) 1.44 [95% confidence interval (CI): 1.05-1.98]). Moreover, more severe ARDS was associated with a higher risk of poor neurological outcomes (mild: reference; moderate: adjusted HR 1.66 [95% CI: 1.10-2.49]; and severe: adjusted HR 1.76 [95% CI: 1.16-2.65]). Therefore, development of ARDS after CA was associated with unfavorable neurologic outcomes and had a linear association with ARDS severity. Early recognition and proper management of ARDS may be useful during post-CA care.

Impact of Lung Compliance on Neurological Outcome in Patients with Acute Respiratory Distress Syndrome Following Out-of-Hospital Cardiac Arrest

(1) Background: Acute respiratory distress syndrome (ARDS) following cardiac arrest is common and associated with in-hospital mortality. We aim to investigate whether lung compliance during targeted temperature management is associated with neurological outcome in patients with ARDS after out-of-hospital cardiac arrest (OHCA). (2) Methods: This observational study is conducted in the emergency intensive care unit from January 2011 to April 2019 using data from a prospective patient registry. Adult patients (age ≥18 years) who survived non-traumatic OHCA and subsequently developed ARDS based on the Berlin definition are included. Mechanical ventilator parameters such as plateau pressure, tidal volume, minute ventilation, positive end expiratory pressure, and compliance are recorded for 7 days or until death, and categorized as maximum, median, and minimum. The primary outcome is a favorable neurological outcome defined as a Cerebral Performance Category score of 1 or 2 at hospital discharge. (3) Results: Regarding 246 OHCA survivors, 119 (48.4%) patients developed ARDS. A favorable neurologic outcome was observed in 23 (19.3%). Patients with a favorable outcome have a significantly higher lung compliance (38.6 mL/cm H₂O versus 27.5 mL/cm H₂O), lower inspiratory pressure (12.0 cm H₂O versus 16.0 cm H₂O), and lower plateau pressure (17.0 cm H₂O versus 21.0 cm H₂O) than those with a poor neurologic outcome (all p < 0.01). Concerning time-dependent cox regression models, all maximum (adjusted hazard ratio [HR] 1.05, 95% confidence interval [CI] 1.02–1.09), minimum (HR 1.08, 95% CI 1.03–1.13), and median (HR 1.06, 95% CI 1.02–1.09) compliances are independently associated with a good neurologic outcome. Maximum compliance, >32.5 mL/cm H₂O at day 1, has the highest area under the receiver operating characteristic curve (0.745) with a positive predictive value of 90.4%. (4) Conclusions: Lung compliance may be an early predictor of intact neurologic survival in patients with ARDS following cardiac arrest.

Imaging for Neuroprognostication After Cardiac Arrest: Systematic Review and Meta-analysis

BACKGROUND

Predicting neurological outcome in comatose survivors of cardiac arrest relies on clinical findings, radiological and neurophysiological test results. To evaluate the predictive accuracy of brain computed tomography (CT) and magnetic resonance imaging (MRI) for prognostication of neurological outcomes after cardiac arrest.

METHODS

We searched MEDLINE (database inception to August 2018) and included all observational cohort studies or randomized controlled trials including adult (16 years or older) survivors of cardiac arrest which evaluated the diagnostic accuracy of CT or MRI for predicting neurologic outcome or mortality. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. All review stages were conducted independently by 2 reviewers, and where possible data were pooled using bivariate meta-analysis. The main outcome was to evaluate the of accuracy of CT and MRI in neuroprognostication of patients after cardiac arrest.

RESULTS

We included 44 studies that examined brain CT (n = 24) or MRI (n = 21) in 4008 (n per study, 9-398) patients. Decreased grey to white matter ratio on CT (20 studies) was useful for predicting poor neurological outcome (sensitivity 0.44, 95% CI 0.29-0.60; specificity 0.97, 95% CI 0.93-0.99; positive likelihood ratio [LR+] 13.8, 95% CI 6.9-27.7). Similarly, diffusion-weighted imaging (DWI) on MRI (16 studies; sensitivity 0.77, 95% CI 0.65-0.85; specificity 0.92, 95% CI 0.85-0.96; LR+ 9.2, 95% CI 5.2-16.4) and DWI and fluid-attenuated inversion recovery (FLAIR) MRI (4 studies, sensitivity 0.70, 95% CI 0.43-0.88; specificity 0.95, 95% CI 0.79-0.99; LR+ 13.4, 95% CI 3.5-51.2) were useful for predicting poor neurological outcomes. We found marked heterogeneity in timing of radiological examinations and neurological assessments relative to the cardiac arrest.

CONCLUSION

Decreased grey to white matter ratio on CT and DWI or DWI and FLAIR on MRI are useful adjuncts for predicting poor early neurological outcome after cardiac arrest.

Prediction of poor outcome after hypoxic-ischemic brain injury by diffusion-weighted imaging: A systematic review and meta-analysis

Accurate prediction of the neurological outcome following hypoxic-ischemic brain injury (HIBI) remains difficult. Diffusion-weighted imaging (DWI) can detect acute and subacute brain abnormalities following global cerebral hypoxia. Therefore, DWI can be used to predict the outcomes of HIBI. To this end, we searched the PubMed, EMBASE, and Cochrane Library databases for studies that examine the diagnostic accuracy of DWI in predicting HIBI outcomes in adult patients between January1995 and September 2019. Next, we conducted a comprehensive meta-analysis using the Meta-DiSc and several complementary techniques. Following the application of inclusion and exclusion criteria, a total of 28 studies were included with 98 data subsets. The overall sensitivity and specificity, with 95% confidence interval, were 0.613(0.599-0.628) and 0.958(0.947-0.967), respectively, and the area under the curve was 0.9090. Significant heterogeneity among the included studies and a threshold effect were observed (p<0.001). Different positive indices were the major sources for the heterogeneity, followed by the anatomical region examined, both of which significantly affected the prognostic accuracy. In conclusion, we demonstrated that DWI can be an instrumental modality in predicting the outcome of HIBI with good prognostic accuracy. However, the lack of clear and generally accepted positive indices limits its clinical application. Therefore, using more reliable positive indices and combining DWI with other clinical predictors may improve the diagnostic accuracy of HIBI.

The Influence of Therapeutics on Prognostication After Cardiac Arrest

PURPOSE OF REVIEW

The goal of this review is to highlight the influence of therapeutic maneuvers on neuro-prognostication measures administered to comatose survivors of cardiac arrest. We focus on the effect of sedation regimens in the setting of targeted temperature management (TTM), one of the principle interventions known to improve neurological recovery after cardiac arrest. Further, we discuss the critical need for novel markers, as well as refinement of existing markers, among patients receiving extracorporeal membrane oxygenation (ECMO) in the setting of failed conventional resuscitation, known as extracorporeal cardiopulmonary resuscitation (ECPR).

RECENT FINDINGS

Automated pupillometry may have some advantage over standard pupillary examination for prognostication following TTM, sedation, or the use of ECMO after cardiac arrest. New serum biomarkers such as Neurofilament light chain have shown good predictive abilities and need further validation in these populations. There is a high-level uncertainty in brain death declaration protocols particularly related to apnea testing and appropriate ancillary tests in patients receiving ECMO. Both sedation and TTM alone and in combination have been shown to affect prognostic markers to varying degrees. The optimal approach to analog-sedation is unknown, and requires further study. Moreover, validation of known prognostic markers, as well as brain death declaration processes in patients receiving ECMO is warranted. Data on the effects of TTM, sedation, and ECMO on biomarkers (e.g., neuron-specific enolase) and electrophysiology measures (e.g., somatosensory-evoked potentials) is sparse. The best approach may be one customized to the individual patient, a precision-medicine approach.

Multimodal approach for neurologic prognostication of out-of-hospital cardiac arrest patients undergoing targeted temperature management

AIM

Since the introduction of targeted temperature management (TTM), the accuracy and timing of prognostic tests for post-cardiac arrest patients have changed. Although previous studies have demonstrated the effectiveness of a multimodal approach in assessing the prognosis of TTM patients, few studies have investigated an optimised strategy that sequentially combines different prognostic modalities. This study identified an optimal sequential combination of prognostic modalities to predict poor neurologic outcomes in patients undergoing TTM.

METHODS

We performed a retrospective analysis using TTM management registry data. All patients underwent an identical sequence of prognostic tests at fixed timings. The sequence included brain computed tomography (CT), serum neuron-specific enolase (NSE), electrophysiological examination, neurologic examination, and diffusion-weighted imaging. We used hierarchical classification and regression tree analysis to find the optimal prognostic model. The primary measure was a poor neurologic outcome at one month after cardiac arrest.

RESULTS

A total of 192 patients were included and 103 patients (53.6%) had poor neurologic outcomes. The final model consisted of brain CT, serum NSE, electroencephalogram, somatosensory-evoked potentials, and pupil light reflex. Our model predicted poor outcomes with a 0% false positive rate. Moreover, our model had an area under the receiver operating characteristic curve value of 0.911 (95% confidence interval, 0.872-0.950), which was significantly higher than that of each prognostic modality alone.

CONCLUSIONS

Our stepwise model showed excellent prognostic ability to predict poor outcomes at one month after cardiac arrest and may be used to minimise the risk of false pessimistic predictions in patients undergoing TTM.

Brain imaging in comatose survivors of cardiac arrest: Pathophysiological correlates and prognostic properties

INTRODUCTION

Hypoxic-ischemic brain injury is the main cause of death and disability of comatose patients after cardiac arrest. Early and reliable prognostication is challenging. Common prognostic tools include clinical neurological examination and electrophysiological measures. Brain imaging is well established for diagnosis of focal cerebral ischemia but has so far not found worldwide application in this patient group.

OBJECTIVE

To review the value of Computed Tomography (CT), Magnetic Resonance Imaging (MRI), and Positron Emission Tomography (PET) for early prediction of neurological outcome of comatose survivors of cardiac arrest.

METHODS

A literature search was performed to identify publications on CT, MRI or PET in comatose patients after cardiac arrest.

RESULTS

We included evidence from 51 articles, 21 on CT, 27 on MRI, 1 on CT and MRI, and 2 on PET imaging. Studies varied regarding timing of measurements, choice of determinants, and cut-off values predicting poor outcome. Most studies were small (n = 6-398) and retrospective (60%). In general, cytotoxic oedema, defined by a grey-white matter ratio <1.10, derived from CT, or MRI-diffusion weighted imaging <650 × 10^-6 mm²/s in >10% of the brain could differentiate between patients with favourable and unfavourable outcomes on a group level within 1-3 days after cardiac arrest. Advanced imaging techniques such as functional MRI or diffusion tensor imaging show promising results, but need further evaluation.

CONCLUSION

CT derived grey-white matter ratio and MRI based measures of diffusivity and connectivity hold promise to improve outcome prediction after cardiac arrest. Prospective validation studies in a multivariable approach are needed to determine the additional value for the individual patient.

Acute brain lesions on magnetic resonance imaging in relation to neurological outcome after cardiac arrest

BACKGROUND

Magnetic resonance imaging (MRI) of the brain including diffusion-weighted imaging (DWI) is reported to have high prognostic accuracy in unconscious post-cardiac arrest (CA) patients. We documented acute MRI findings in the brain in both conscious and unconscious post-CA patients treated with target temperature management (TTM) at 32-34°C for 24 h as well as the relation to patients' neurological outcome after 6 months.

METHODS

A prospective observational study with MRI was performed regardless of the level of consciousness in post-CA patients treated with TTM. Neurological outcome was assessed using the Cerebral Performance Categories scale and dichotomized into good and poor outcome.

RESULTS

Forty-six patients underwent MRI at 3-5 days post-CA. Patients with good outcome had minor, mainly frontal and parietal, lesions. Acute hypoxic/ischemic lesions on MRI including DWI were more common in patients with poor outcome (P = 0.007). These lesions affected mostly gray matter (deep or cortical), with or without involvement of the underlying white matter. Lesions in the occipital and temporal lobes, deep gray matter and cerebellum showed strongest associations with poor outcome. Decreased apparent diffusion coefficient, was more common in patients with poor outcome.

CONCLUSIONS

Extensive acute hypoxic/ischemic MRI lesions in the cortical regions, deep gray matter and cerebellum detected by visual analysis as well as low apparent diffusion coefficient values from quantitative measurements were associated with poor outcome. Patients with good outcome had minor hypoxic/ischemic changes, mainly in the frontal and parietal lobes.

Predictors of good neurologic outcome after resuscitation beyond 30 min in out-of-hospital cardiac arrest patients undergoing therapeutic hypothermia

Neurologically intact survival after cardiac arrest is possible even after prolonged resuscitation efforts. However, the factors associated with good neurologic outcome in these patients remain unknown. This study identifies predictors associated with good neurologic outcome after resuscitation beyond 30 min in out-of-hospital cardiac arrest (OHCA) patients treated with targeted temperature management (TTM). This multicenter, registry-based, retrospective cohort study conducted in 24 hospitals across South Korea between 2007 and 2012 includes adult (≥18 years) non-traumatic OHCA patients with prolonged (>30 min) downtime who underwent TTM treatment. Good neurologic outcomes were defined as cerebral performance category scores of ≤2. Of the 930 comatose adult cardiac arrest patients treated with TTM, 423 patients with prolonged downtime were included. A total of 76 (18.0%) had good neurologic outcome. Multivariable analysis reveal that age <65 years (OR 7.91, 95% CI 3.18-19.68), initial shockable rhythm (OR 6.31, 95% CI 3.40-11.74), and witnessed arrest (OR 3.81, 95% CI 1.73-8.45) are associated with good neurologic outcome. The sensitivity and specificity for good neurologic outcome in patients with age <65 years, shockable rhythm, and witnessed arrest are 90.8% and 41.2, 67.6 and 79.5%, and 81.6 and 41.2%, respectively. In prolonged cardiac arrest patients, initial shockable rhythm, age <65 years, or witnessed arrest are predictors for neurologic intact survival.

Preoperative prediction of sentinel lymph node metastasis in breast cancer based on radiomics of T2-weighted fat-suppression and diffusion-weighted MRI

OBJECTIVES

To predict sentinel lymph node (SLN) metastasis in breast cancer patients using radiomics based on T₂-weighted fat suppression (T₂-FS) and diffusion-weighted MRI (DWI).

METHODS

We enrolled 146 patients with histologically proven breast cancer. All underwent pretreatment T₂-FS and DWI MRI scan. In all, 10,962 texture and four non-texture features were extracted for each patient. The 0.623 + bootstrap method and the area under the curve (AUC) were used to select the features. We constructed ten logistic regression models (orders of 1-10) based on different combination of image features using stepwise forward method.

RESULTS

For T₂-FS, model 10 with ten features yielded the highest AUC of 0.847 in the training set and 0.770 in the validation set. For DWI, model 8 with eight features reached the highest AUC of 0.847 in the training set and 0.787 in the validation set. For joint T₂-FS and DWI, model 10 with ten features yielded an AUC of 0.863 in the training set and 0.805 in the validation set.

CONCLUSIONS

Full utilisation of breast cancer-specific textural features extracted from anatomical and functional MRI images improves the performance of radiomics in predicting SLN metastasis, providing a non-invasive approach in clinical practice.

KEY POINTS

• SLN biopsy to access breast cancer metastasis has multiple complications. • Radiomics uses features extracted from medical images to characterise intratumour heterogeneity. • We combined T ₂ -FS and DWI textural features to predict SLN metastasis non-invasively.

The impact of downtime on neurologic intact survival in patients with targeted temperature management after out-of-hospital cardiac arrest: National multicenter cohort study

AIM OF STUDY

The association between long duration of resuscitation efforts in out-of-hospital cardiac arrest (OHCA) and neurologic outcome is unclear and understudied with advancements in post-cardiac arrest care and high-quality cardiopulmonary resuscitation. We investigated how downtime, defined as the interval from collapse-to-return of spontaneous circulation (ROSC), impacts on neurologic outcome in OHCA patients treated with targeted temperature management (TTM).

METHODS

A multicenter, registry-based, retrospective cohort study was conducted using cases from 24 hospitals across South Korea. Of the 930 adults (≥18 years) non-traumatic OHCA patients treated with TTM between January 2007 and December 2012 at these hospitals, we included 858 patients who had sufficient data for calculating downtime. Good neurologic outcome was defined as a cerebral performance category score of 1 or 2.

RESULTS

Median downtime was 30.0 (22.0-41.0min) and 242 patients (28.2%) had good neurologic outcome. When downtime was divided by 10-min intervals (≤10min, 11-20min, 21-30min, 31-40min, 41-50min, 51-60min, and >60min), their neurologically intact survival rate were 48.2%, 51.6%, 29.2%, 22.1%, 16.1%, 14.8%, and 7.1%, respectively (p=0.01). Although downtime was associated with poor neurologic outcome [odds ratio 1.06 (1.05-1.08), p<0.01], the area under the receiver operating characteristic curve of downtime for outcome was only 0.67, 95% CI (0.63-0.71). Furthermore, even with downtime >20min, 22.2% (150/526) patients still had a good neurologic outcome, and this percentage increased to 50.3% (93/185) in patients with an initial shockable rhythm, and 31.1% (134/431) with age <65 years.

CONCLUSIONS

We found that neurologically intact survival can occur at prolonged downtimes and were unable to identify a downtime for which survivability was clearly futile. These data suggest that downtime should not be considered as a factor in determining whether to provide aggressive post-arrest care, especially in patients with young patients or those with an initially shockable rhythm.

Neurological prognostication of outcome in patients in coma after cardiac arrest

Management of coma after cardiac arrest has improved during the past decade, allowing an increasing proportion of patients to survive, thus prognostication has become an integral part of post-resuscitation care. Neurologists are increasingly confronted with raised expectations of next of kin and the necessity to provide early predictions of long-term prognosis. During the past decade, as technology and clinical evidence have evolved, post-cardiac arrest prognostication has moved towards a multimodal paradigm combining clinical examination with additional methods, consisting of electrophysiology, blood biomarkers, and brain imaging, to optimise prognostic accuracy. Prognostication should never be based on a single indicator; although some variables have very low false positive rates for poor outcome, multimodal assessment provides resassurance about the reliability of a prognostic estimate by offering concordant evidence.