Serum and cerebrospinal fluid C-reactive protein levels as predictors of vasospasm in aneurysmal subarachnoid hemorrhage. Clinical article

Association of the C-reactive protein/albumin ratio with the prognosis of Aneurysmal Subarachnoid Hemorrhage: A systematic review

The C-Reactive Protein/Albumin Ratio (CAR) is being studied as a potential predictor of severe outcomes in various diseases. Our study aimed to review current evidence on the prognostic value of CAR in patients with aneurysmal subarachnoid hemorrhage (aSAH). We conducted a systematic search in PubMed, Embase, Scopus, Web of Science, and Google Scholar up to April 2023 and assessed the risk of bias using the NewCastle-Ottawa tool. A narrative synthesis was performed, and the GRADE system was used to evaluate the certainty of the evidence. Out of 534 articles, 4 were selected. We found that a higher CAR level is moderately associated with a lower score on the Glasgow Outcome Scale at 3 months and a higher incidence of in-hospital mortality. However, no significant association was found with the modified Rankin scale or delayed cerebral ischemia. Although the evidence is limited, CAR could be a useful tool for predicting poor prognosis in aSAH patients, but more prospective studies are needed to determine optimal cut-off points and include CAR in long-term prognostic models.

Association Between High Preoperative White Blood Cell-to-Hemoglobin Ratio and Postoperative Symptomatic Cerebral Vasospasm in Patients With Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Cerebral vasospasm after aneurysmal subarachnoid hemorrhage (ASAH) is a serious complication and has a strong relationship with systemic inflammatory responses. Given previously reported relationships between leukocytosis and anemia with ASAH-related cerebral vasospasm, this study examined the association between the preoperative white blood cell-to-hemoglobin ratio (WHR) and postoperative symptomatic cerebral vasospasm (SCV) in patients with ASAH.

METHODS

Demographic, preoperative (comorbidities, ASAH characteristics, laboratory findings), intraoperative (operation and anesthesia), and postoperative (SCV, other neurological complications, clinical course) data were retrospectively analyzed in patients with ASAH who underwent surgical or endovascular treatment of the culprit aneurysm. Patients were divided into high-WHR (n=286) and low-WHR (n=257) groups based on the optimal cutoff value of preoperative WHR (0.74), and stabilized inverse probability weighting was performed between the 2 groups. The predictive power of the WHR and other preoperative systemic inflammatory indices (neutrophil-to-albumin, neutrophil-to-lymphocyte, platelet-to-lymphocyte, platelet-to-neutrophil, platelet-to-white blood cell ratios, and systemic immune-inflammation index) for postoperative SCV was evaluated.

RESULTS

Postoperative SCV was more frequent in the high-WHR group than in the low-WHR group before (33.2% vs. 12.8%; P <0.001) and after (29.4% vs. 19.1%; P =0.005) inverse probability weighting. Before weighting, the predictive power for postoperative SCV was the highest for the WHR among the preoperative systematic inflammatory indices investigated (area under receiver operating characteristics curve 0.66, P <0.001). After weighting, preoperative WHR ≥0.74 was independently associated with postoperative SCV (odds ratio 1.76; P =0.006).

CONCLUSIONS

High preoperative WHR was an independent predictor of postoperative SCV in patients with ASAH.

Systemic C-Reactive Protein Predicts Cerebral Vasospasm and Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage: A Retrospective Observational Study

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) is often complicated by cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI), which significantly impact patient outcomes. The study aimed to investigate the predictive value of systemic serum biomarker levels for CVS and DCI following aSAH.

METHODS

We retrospectively analyzed data for 450 aSAH patients admitted to University Hospital Düsseldorf between January 2011 and October 2021. Serum biomarkers were measured on admission. The occurrence of CVS and DCI was assessed based on clinical and radiological criteria. Multivariate logistic regression analysis was performed to determine the independent association of serum biomarkers with CVS and DCI. We compared the predictive values of various models using the area under the receiver operating characteristic curve.

RESULTS

Of the 450 patients, 126 (28.0%) developed CVS, 123 (27.3%) developed DCI, and 62 (13.8%) developed co-occurring CVS and DCI. Patients with CVS, DCI, or both had significantly higher admission C-reactive protein (CRP) levels than those without these complications (P < 0.001). Elevated CRP levels were independently associated with an increased risk of CVS, DCI, and co-occurring CVS and DCI (P < 0.05). CRP demonstrated a higher predictive value for CVS (area under the curve [AUC]: 0.811) and co-occurring CVS and DCI (AUC: 0.802) compared to DCI alone (AUC: 0.690).

CONCLUSIONS

Our findings suggest that admission systemic CRP levels can serve as a more valuable predictor for developing CVS than DCI following aSAH. Incorporating CRP into clinical assessments may aid in risk stratification and early intervention strategies for patients at high risk of these complications.

Predicting Vasospasm and Early Mortality in Severe Traumatic Brain Injury: A Model Using Serum Cytokines, Neuronal Proteins, and Clinical Data

BACKGROUND AND OBJECTIVES

Prediction of patient outcomes after severe traumatic brain injury (sTBI) is limited with current clinical tools. This study aimed to improve such prognostication by combining clinical data and serum inflammatory and neuronal proteins in patients with sTBI to develop predictive models for post-traumatic vasospasm (PTV) and mortality.

METHODS

Fifty-three adult civilian patients were prospectively enrolled in the sTBI arm of the Surgical Critical Care Initiative (SC2i). Clinical, serum inflammatory, and neuronal protein data were combined using the parsimonious machine learning methods of least absolute shrinkage and selection operator (LASSO) and classification and regression trees (CART) to construct parsimonious models for predicting development of PTV and mortality.

RESULTS

Thirty-six (67.9%) patients developed vasospasm and 10 (18.9%) died. The mean age was 39.2 years; 22.6% were women. CART identified lower IL9, lower presentation pulse rate, and higher eotaxin as predictors of vasospasm development (full data area under curve (AUC) = 0.89, mean cross-validated AUC = 0.47). LASSO identified higher Rotterdam computed tomography score and lower age as risk factors for vasospasm development (full data AUC 0.94, sensitivity 0.86, and specificity 0.94; cross-validation AUC 0.87, sensitivity 0.79, and specificity 0.93). CART identified high levels of eotaxin as most predictive of mortality (AUC 0.74, cross-validation AUC 0.57). LASSO identified higher serum IL6, lower IL12, and higher glucose as predictive of mortality (full data AUC 0.9, sensitivity 1.0, and specificity 0.72; cross-validation AUC 0.8, sensitivity 0.85, and specificity 0.79).

CONCLUSION

Inflammatory cytokine levels after sTBI may have predictive value that exceeds conventional clinical variables for certain outcomes. IL-9, pulse rate, and eotaxin as well as Rotterdam score and age predict development of PTV. Eotaxin, IL-6, IL-12, and glucose were predictive of mortality. These results warrant validation in a prospective cohort.

Predictive Value of Fibrin Fibrinogen Degradation Products-to-Potassium Ratio for Poor Functional Outcome in Patients with Aneurysmal Subarachnoid Hemorrhage: A Retrospective Case-Control Study

BACKGROUND

The relationship of fibrin(ogen) degradation products (FDPs) and potassium with the functional outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH) is still uncertain. This study aims to evaluate the predictive value of a novel combination biomarker, the FDP-to-potassium ratio (FPR), for poor functional outcomes in patients with aSAH.

METHODS

A total of 425 consecutive patients with aSAH at a single center were retrospectively enrolled in our study. An unfavorable outcome was defined as a modified Rankin Scale (mRS) score of 3-6 at 3 months after discharge. Univariate analysis and multivariable logistic regression were performed for baseline information and laboratory parameters recorded at admission. In addition, the receiver operating characteristic curve was plotted, and propensity score matching was performed based on the FPR.

RESULTS

On the basis of mRS grade, 301 patients were classified as having favorable outcomes, and 124 patients were assessed as having unfavorable outcomes. FPR levels were significantly correlated with mRS grade (r[Spearman] = 0.410; P < 0.001). Multivariate logistic regression analysis showed that age (odds ratio [OR] 1.043, 95% confidence interval [CI] 1.016-1.071; P = 0.002), white blood cell count (OR 1.150, 95% CI 1.044-1.267; P = 0.005), potassium (OR 0.526, 95% CI 0.291-0.949; P = 0.033), World Federation of Neurosurgical Societies grade (OR 1.276, 95% CI 1.055-1.544; P = 0.012), and FPR (OR 1.219, 95% CI 1.102-1.349; P < 0.001) at admission were independently associated with poor functional outcomes. The DeLong test showed that the area under the receiver operating characteristic curve of FPR was higher than that of age, white blood cell count, potassium, World Federation of Neurosurgical Societies grade, or FDP alone, indicating that FPR had better predictive potential than these other variables. After 1:1 propensity score matching (FPR ≥ 1.45 vs. FPR < 1.45), the rate of poor prognosis was still significantly increased in the high-FPR group (48/121 [39.7%] vs. 16/121 [13.2%], P < 0.001).

CONCLUSIONS

Fibrin(ogen) degradation product-to-potassium ratio is an independent predictor of poor outcomes for patients with aSAH and may be a promising tool for clinicians to evaluate patients' functional prognosis.

Serum C-reactive protein value on day 14 as a possible prognostic factor of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Serum C-reactive protein (CRP), as a reflection of early brain injury at onset, is a prognostic factor in aneurysmal subarachnoid hemorrhage (aSAH). However, in some severe cases, patients exhibit a good prognosis despite their elevated serum CRP level. Therefore, we examined the relationship between serum CRP transitions in the acute phase of aSAH and the prognosis.

METHODS

We recruited 63 patients with aSAH and retrospectively analyzed the relationships between the serum CRP transitions during the acute phase and the prognosis, patient background, and clinical course.

RESULTS

Serum CRP values on days 1, 3, and 14 were significantly lower in the good prognosis group than those in the poor prognosis group. Moreover, serum CRP values on days 1 and 14 significantly affected the prognosis in the multiple regression analysis.

CONCLUSIONS

A low serum CRP value on day 14, in addition to that on day 1 as reported previously, is associated with a good prognosis of aSAH. Furthermore, a good prognosis of aSAH is determined not only by absence of early brain injury at onset but also by appropriate management to obtain a low serum CRP value on day 14.

CLR (C-Reactive Protein to Lymphocyte Ratio) Served as a Promising Predictive Biomarker for Cerebral Vasospasm in Aneurysmal Subarachnoid Hemorrhage (aSAH): A Retrospective Cohort Study

Background: Subarachnoid hemorrhage is a devastating disease. Even after state-of-the-art treatment patients suffer from complications, including cerebral vasospasm (CVS), delayed cerebral ischemia (DCI), and chronic hydrocephalus (CH) following aneurysmal subarachnoid hemorrhage (aSAH). The aim of our study is to identify the predictive value of the C-reactive protein to lymphocyte ratio (CLR) for neurological functional outcome and complications after aSAH. Methods: We retrospectively analyzed a total of 166 aSAH patients who met the inclusion criteria enrolled in our study. Multivariate logistic regression analyses were performed to evaluate the independent risk factors. The predictive value of different models was compared by calculating the areas under the receiver operating characteristic (ROC) curve. Results: On-admission levels of CLR in patients with poor outcomes (6 months mRS 3-6), CVS, DCI, and CH were significantly higher than those in patients with good outcomes (6 months mRS 0-2), non-CVS, non-DCI, and non-CH. Multivariate logistic regression analysis revealed that admission CLR was independently associated with CVS (OR [95% CI] 2.116 [1.507-2.971]; p < 0.001), and DCI (OR [95% CI] 1.594 [1.220-2.084]; p = 0.001). In ROC analysis, the area under the curve (AUC) of CLR for poor outcomes (6 months mRS 3-6), CVS, DCI, and CH prediction were (AUC [95% CI] 0.639 [0.555-0.724]; p = 0.002), (AUC [95% CI] 0.834 [0.767-0.901]; p < 0.001), (AUC [95% CI] 0.679 [0.581-0.777]; p < 0.001), and (AUC [95% CI] 0.628 [0.543-0.713]; p = 0.005) revealing that admission CLR had a favorable predictive value for CVS after aSAH. The sensitivity and specificity of admission CLR for CVS prediction were 77.1% and 75.4%. On-admission CLR of 0.757 mg × 10-6 was identified as the best cutoff threshold to discriminate between CVS and non-CVS (CVS: CLR < 0.757 mg × 10-6 11/100 [11.0%] vs. CLR ≥ 0.757 mg × 10-6 37/66 [56.1%]; p < 0.001). Conclusions: High levels of on-admission CLR serve as an independent risk factor for CVS and DCI after aSAH. Admission CLR is an easy-to-quantify laboratory parameter that efficiently predicts the CVS after aSAH, which can provide some guidance for clinicians to evaluate for possible progression and treatment strategies in patients with aSAH.

C-Reactive Protein: Pathophysiology, Diagnosis, False Test Results and a Novel Diagnostic Algorithm for Clinicians

The current literature provides a body of evidence on C-Reactive Protein (CRP) and its potential role in inflammation. However, most pieces of evidence are sparse and controversial. This critical state-of-the-art monography provides all the crucial data on the potential biochemical properties of the protein, along with further evidence on its potential pathobiology, both for its pentameric and monomeric forms, including information for its ligands as well as the possible function of autoantibodies against the protein. Furthermore, the current evidence on its potential utility as a biomarker of various diseases is presented, of all cardiovascular, respiratory, hepatobiliary, gastrointestinal, pancreatic, renal, gynecological, andrological, dental, oral, otorhinolaryngological, ophthalmological, dermatological, musculoskeletal, neurological, mental, splenic, thyroid conditions, as well as infections, autoimmune-supposed conditions and neoplasms, including other possible factors that have been linked with elevated concentrations of that protein. Moreover, data on molecular diagnostics on CRP are discussed, and possible etiologies of false test results are highlighted. Additionally, this review evaluates all current pieces of evidence on CRP and systemic inflammation, and highlights future goals. Finally, a novel diagnostic algorithm to carefully assess the CRP level for a precise diagnosis of a medical condition is illustrated.

Biomarkers in aneurysmal subarachnoid hemorrhage: A short review

Poor outcomes of aneurysmal subarachnoid hemorrhage (aSAH) can be the result of the initial catastrophic event or the many acute or delayed neurological complications. Recent evidence suggests that some molecules play a critical role in both events, through some unknown pathways involved. Understanding the role of these molecules in these events could allow to improve diagnostic accuracy, guide management, and prevent long-term disability in aSAH. Here we present the studies on aSAH biomarkers present in current medical literature, highlighting their roles and main results.

Continuous lumbar drainage after aneurysmal subarachnoid hemorrhage decreased malondialdehyde in cerebrospinal fluid and improved outcome

PURPOSE

The use of a continuous lumbar drain (LD) for the treatment of aneurysmal subarachnoid hemorrhage (aSAH), and malondialdehyde (MDA), a marker of oxidative stress, is correlated with clinical outcome. This study aimed to investigate the relationship between LD placement and MDA level after aSAH.

METHODS

Patients with modified Fisher's grade III and IV aSAH who underwent early aneurysm obliteration were enrolled. Cerebrospinal fluid (CSF) was obtained on day 7 after aSAH in non-LD group. In LD group, the LD was inserted on day 3 after aSAH for continuous CSF drainage. The levels of intrathecal hemoglobin, total bilirubin, ferritin, and MDA were measured.

RESULTS

There were 41 patients in non-LD group (age: 58.7 ± 13.7 years; female: 61.0%) and 48 patients in LD group (age: 58.3 ± 10.4 years; female: 79.2%). There were more favorable outcomes (Glasgow Outcome Scale ≥4) at 3 months after aSAH in LD group (p = 0.0042). The intrathecal hemoglobin, total bilirubin, ferritin, and MDA levels at day 7 after aSAH were all significantly lower in LD group. An older age (>60 years) (p = 0.0293), higher MDA level in the CSF (p = 0.0208), and delayed ischemic neurological deficit (p = 0.0451) were independent factors associated with unfavorable outcomes. LD placement was associated with a decreased intrathecal MDA level on day 7 after aSAH (p < 0.001).

CONCLUSION

The intrathecal MDA level at day 7 after aSAH can be an effective outcome indicator in modified Fisher's grade III/IV aSAH. Continuous CSF drainage via a LD can decrease the intrathecal MDA level and improve the functional outcome.

C-reactive protein elevation predicts in-hospital deterioration after aneurysmal subarachnoid hemorrhage: a retrospective observational study

Background

There is increasing evidence that inflammation plays a role in the pathogenesis of aneurysmal subarachnoid hemorrhage (aSAH) and in the development of delayed cerebral ischemia (DCI). However, the assessment and interpretation of classically defined inflammatory parameters is difficult in aSAH patients. The objective of this study was to investigate the relationship between easily assessable findings (hyperventilation, fever, white blood cell count (WBC), and C-reactive protein (CRP)) and the occurrence of DCI and unfavorable neurological outcome at discharge in aSAH patients.

Methods

Retrospective analysis of prospectively collected data from a single center cohort. We evaluated the potential of clinical signs of inflammation (hyperventilation, fever) and simple inflammatory laboratory parameters CRP and WBC to predict unfavorable outcomes at discharge and DCI in a multivariate analysis. A cutoff value for CRP was calculated by Youden’s J statistic. Outcome was measured using the modified Rankin score at discharge, with an unfavorable outcome defined as modified Rankin scale (mRS) > 3.

Results

We included 97 consecutive aSAH patients (63 females, 34 males, mean age 58 years) in the analysis. Twenty-one (22%) had major disability or died by the time of hospital discharge. Among inflammatory parameters, CRP over 100 mg/dl on day 2 was an independent predictor for worse neurological outcome at discharge. The average C-reactive protein level in the first 14 days was higher in patients with a worse neurological outcome (96.6, SD 48.3 vs 56.3 mg/dl, SD 28.6) in the first 14 days after aSAH. C-reactive protein on day 2 was an indicator of worse neurological outcome. No inflammatory parameter was an independent predictor of DCI. After multivariate adjustment, DCI, increased age, and more than 1 day of mechanical ventilation were significant predictors of worse neurological outcome.

Conclusions

Early elevated CRP levels were a significant predictor of worse neurological outcome at hospital discharge and may be a useful marker of later deterioration in aSAH.

Leukocytosis and C-Reactive Protein May Predict Development of Secondary Cerebral Vasospasm in Patients with Aneurysmal Subarachnoid Hemorrhage

Background and Objectives: Secondary cerebral vasospasm (CV) with subsequent delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) remains an unpredictable pathology. The aim of this retrospective study was to investigate the association between inflammatory parameters, white blood cell (WBC) count, and C-reactive protein plasma levels (CRP) and the occurrence of secondary CV in patients with aSAH. Materials and Methods: The medical records of 201 Intensive Care Unit patients in Riga East University Hospital with aSAH were retrospectively reviewed in a 24-month period. WBC count and CRP values were observed at admission to the hospital and on the third day. According to the inclusion criteria, 117 (48 males) participants were enrolled for further analysis, with average age of 56 ± 15 years (mean ± SD). In total, secondary CV was diagnosed in 21.4% of cases, and DCI in 22.4% of cases. The patients were classified into three groups: SAH-CV group (n = 25), SAH-DCI group (n = 12), and SAH or control group (n = 80), for comparative analysis. Results: We found that SAH-CV patients demonstrated notably higher inflammatory parameters compared to controls: WBC 13.2 ± 3.3 × 10⁹/L vs. 11.2 ± 3.7 × 10⁹/L; p = 0.01 and CRP median 9.3 mg/L vs. 1.9 mg/L; p < 0.001, respectively. We found that the odds of developing CV increased by 5% for each CRP increase of 1 mg/L at admission (OR, 1.05; CI, 1.014–1.087; p = 0.006). Concomitantly, the odds increased by 16% for every rise in WBC count of 1 × 10⁹/L (OR, 1.16; CI, 1.02–1.32; p = 0.02). WBC count was associated with the occurrence of CV with 96% sensitivity and 40% specificity, with a cut off level of 10.015 × 10⁹/L and AUC 0.683; p = 0.006. CRP displayed 54% sensitivity and 90% specificity with a cut off value of 8.9 mg/L and AUC 0.751; p < 0.001. Moreover, higher values of inflammatory parameters at admission correlated with a longer stay in ICU (r = 0.3, p = 0.002 for WBC count and r = 0.305, p = 0.002 for CRP values), and poor outcome (death) was significantly associated with higher CRP values at admission and on the third day (16.1. vs. 2.2. and 57.4. vs. 11.1, p < 0.001, respectively). Higher mortality was detected in SAH-CV patients (32%) compared to controls (6.3%; p < 0.001). Conclusions: Inflammatory parameters such as WBC count and CRP values at admission might be helpful to predict the development of secondary CV.

Role of Monocyte-to-lymphocyte Ratio, Mean Platelet Volume-to-Platelet Count Ratio, C-Reactive Protein and Erythrocyte Sedimentation Rate as Predictor of Severity in Secondary Traumatic Brain Injury: A Literature Review

BACKGROUND: Secondary traumatic brain injury (TBI) is injury to the brain following primary TBI because of neuroinflammation as consequences of neuronal and glial cell injury which cause release of various inflammation cytokine and chemokine. Biomarker examination to predict the severity of secondary TBI is important to provide appropriate treatment to the patient. This article reviews possibility several common laboratory parameter such as monocyte-to-lymphocyte ratio (MLR), mean platelet volume-to-platelet count (PC) ratio (MPV-PCR), c-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) to predict severity of secondary TBI. LITERATURE REVIEW: TBI activates microglia which increase infiltration and proliferation of monocyte. Neuroinflammation also increases thrombopoiesis which leads to increase megakaryocytes production. In the other hand, due to disruption of brain blood vessels because of trauma, coagulation cascade is also activated and leads to consumptive coagulopathy. These are reflected as high monocyte count, low PC, and high MPV. Lymphocyte count is reported low in TBI especially in poor outcome patients. CRP is an acute phase reactant that increased in inflammation condition. In TBI, increased production of Interleukin-6 leads to increase CRP production. In head injured patients, ESR level does not increase significantly in the acute phase of inflammation but last longer when compared to CRP. CONCLUSION: MLR, MPV-PCR, CRP, and ESR could be predictor of severity in secondary TBI.

Association of cerebrospinal fluid protein biomarkers with outcomes in patients with traumatic and non-traumatic acute brain injury: systematic review of the literature

BACKGROUND

Acute brain injuries are associated with high mortality rates and poor long-term functional outcomes. Measurement of cerebrospinal fluid (CSF) biomarkers in patients with acute brain injuries may help elucidate some of the pathophysiological pathways involved in the prognosis of these patients.

METHODS

We performed a systematic search and descriptive review using the MEDLINE database and the PubMed interface from inception up to June 29, 2021, to retrieve observational studies in which the relationship between CSF concentrations of protein biomarkers and neurological outcomes was reported in patients with acute brain injury [traumatic brain injury, subarachnoid hemorrhage, acute ischemic stroke, status epilepticus or post-cardiac arrest]. We classified the studies according to whether or not biomarker concentrations were associated with neurological outcomes. The methodological quality of the studies was evaluated using the Newcastle-Ottawa quality assessment scale.

RESULTS

Of the 39 studies that met our criteria, 30 reported that the biomarker concentration was associated with neurological outcome and 9 reported no association. In TBI, increased extracellular concentrations of biomarkers related to neuronal cytoskeletal disruption, apoptosis and inflammation were associated with the severity of acute brain injury, early mortality and worse long-term functional outcome. Reduced concentrations of protein biomarkers related to impaired redox function were associated with increased risk of neurological deficit. In non-traumatic acute brain injury, concentrations of CSF protein biomarkers related to dysregulated inflammation and apoptosis were associated with a greater risk of vasospasm and a larger volume of brain ischemia. There was a high risk of bias across the studies.

CONCLUSION

In patients with acute brain injury, altered CSF concentrations of protein biomarkers related to cytoskeletal damage, inflammation, apoptosis and oxidative stress may be predictive of worse neurological outcomes.

CRP (C-Reactive Protein) in Outcome Prediction After Subarachnoid Hemorrhage and the Role of Machine Learning

BACKGROUND AND PURPOSE

Outcome prediction after aneurysmal subarachnoid hemorrhage (aSAH) is challenging. CRP (C-reactive protein) has been reported to be associated with outcome, but it is unclear if this is independent of other predictors and applies to aSAH of all grades. Therefore, the role of CRP in aSAH outcome prediction models is unknown. The purpose of this study is to assess if CRP is an independent predictor of outcome after aSAH, develop new prognostic models incorporating CRP, and test whether these can be improved by application of machine learning.

METHODS

This was an individual patient-level analysis of data from patients within 72 hours of aSAH from 2 prior studies. A panel of statistical learning methods including logistic regression, random forest, and support vector machines were used to assess the relationship between CRP and modified Rankin Scale. Models were compared with the full Subarachnoid Hemmorhage International Trialists' (SAHIT) prediction tool of outcome after aSAH and internally validated using cross-validation.

RESULTS

One thousand and seventeen patients were included for analysis. CRP on the first day after ictus was an independent predictor of outcome. The full SAHIT model achieved an area under the receiver operator characteristics curve (AUC) of 0.831. Addition of CRP to the predictors of the full SAHIT model improved model performance (AUC, 0.846, P=0.01). This improvement was not enhanced when learning was performed using a random forest (AUC, 0.807), but was with a support vector machine (AUC of 0.960, P <0.001).

CONCLUSIONS

CRP is an independent predictor of outcome after aSAH. Its inclusion in prognostic models improves performance, although the magnitude of improvement is probably insufficient to be relevant clinically on an individual patient level, and of more relevance in research. Greater improvements in model performance are seen with support vector machines but these models have the highest classification error rate on internal validation and require external validation and calibration.

C-Reactive Protein Levels Are Higher in Patients With Fusiform Intracranial Aneurysms: A Case-Control Study

BACKGROUND

Comprehending the risk factors that contribute to the formation of fusiform aneurysms (FAs) might provide some insight into treatment and prevention strategies. This case-control study aimed to compare the levels of serum C-reactive protein (CRP), as a biomarker, between patients with fusiform and saccular intracranial aneurysms.

METHODS

We retrospectively analyzed medical records from 2010 to 2019. Thirty-five patients were identified as having FAs: 13 (37.1%) were ruptured, and 22 were unruptured. An age-matched sample of 70 controls (2:1) with saccular aneurysms was obtained from the same records: 36 (51.4%) ruptured and 34 unruptured.

RESULTS

Patients with FAs had median CRP values of 0.61 mg/dL (IQR: 1.5), compared with 0.29 mg/dL (IQR: 0.42) in controls (P < 0.01). Within both the ruptured and the unruptured group, median CRP was higher in patients with FAs compared with controls (P < 0.01). Diabetes, smoking status, hypertension, and sex did not significantly influence CRP levels. Age-adjusted analyses showed that fusiform morphology was independently associated with higher CRP levels for unruptured aneurysms (OR 1.2, 95% CI 1.05-1.43), but not for ruptured aneurysms (OR 1.02, 95%CI 0.99-1.05).

CONCLUSIONS

CRP was higher in patients with FAs than controls, and it constituted an independent predictor of fusiform morphology for patients with unruptured aneurysms. Inflammation might be an especially important factor in FA formation and growth, and further studies could use this finding to design new treatment strategies.

Associations Between Levels of High-Sensitivity C-Reactive Protein and Outcome After Intracerebral Hemorrhage

Background: Patients with spontaneous intracerebral hemorrhage (ICH) have high mortality and morbidity rates; approximately one-third of patients with ICH experience hematoma expansion (HE). The spot sign is an established and validated imaging marker for HE. High-sensitivity C-reactive protein (hs-CRP) is an established laboratory marker for inflammation and secondary brain injury following ICH. Objective: To determine the association between the spot sign and hs-CRP, hematoma expansion, and clinical outcomes. Methods: Between December 2014 and September 2016, we prospectively recruited 1,964 patients with acute symptomatic ICH at 13 hospitals in Beijing, China. Next, we selected 92 patients within 24 h of the onset of symptoms from this cohort for the present study. ICH was diagnosed in the emergency room by non-contrast computed tomography (NCCT) scans. Follow-up scans were carried out within 48 h to evaluate patients for HE. Multidetector computed tomography angiography (MDCTA) was also used to identify spot signs. Blood samples were collected from each patient at admission in EDTA tubes (for plasma) or vacutainer tubes (for serum). hs-CRP values were determined by a particle-enhanced immunoturbidimetric assay in the laboratory at Beijing Tiantan Hospital, Capital Medical University. Patients were categorized into two groups according to their hs-CRP levels (hs-CRP <3 mg/L, hs-CRP ≥3 mg/L). Results: The incidences of spot sign and HE in our study cohort were 31.5 and 29.3%, respectively. Following the removal of potential confounding variables, stepwise-forward logistic regression analysis identified that an hs-CRP level ≥3 mg/L was not a significant indicator for either spot sign (p = 0.68) or HE (p = 0.07). However, an hs-CRP level ≥3 mg/L (odds ratio: 16.64, 95% confidence interval: 2.11-131.45, p = 0.008) was identified as an independent predictor of an unfavorable outcome 1 year after acute ICH. Conclusions: Our analyses identified that an hs-CRP level ≥3 mg/L was a significant indicator for an unfavorable outcome 1 year after acute ICH.

Can admission lipoprotein-associated phospholipase A2 predict the symptomatic cerebral vasospasm following aneurysmal subarachnoid hemorrhage?

Background

Inflammation has been believed to be related to the development of cerebral vasospasm following aneurysmal subarachnoid hemorrhage (aSAH). A potential biomarker for vascular inflammation that is well recognized is the lipoprotein-associated phospholipase A2 (Lp-PLA2). However, whether Lp-PLA2 can predict the occurrence of symptomatic cerebral vasospasm (SCV) in aSAH patients is still unknown. Thus, this study aimed to assess the value of Lp-PLA2 for predicting SCV in patients with aSAH.

Methods

Between March 2017 and April 2018, we evaluated 128 consecutive aSAH patients who were admitted in the First Affiliated Hospital of Fujian Medical University. Their Lp-PLA2 level was obtained within 24 h of the initial bleeding. Factors might be related to SCV were analyzed.

Results

Compared to patients without SCV, those with SCV (9.4%, 12/128) had significantly higher Lp-PLA2 level. Multivariate logistic analysis revealed that worse modified Fisher grade (OR = 10.08, 95% CI = 2.04-49.86, P = 0.005) and higher Lp-PLA2 level (OR = 6.66, 95% CI = 1.33-3.30, P = 0.021) were significantly associated with SCV, even after adjustment for confounders. Based on the best threshold, Lp-PLA2 had a sensitivity of 83.3% and a specificity of 51.7% for predicting SCV, as shown by the receiver operating characteristic curve analysis. In the poor World Federation of Neurosurgical Societies grade patient sub-group, patients with Lp-PLA2 > 200 μg/L had significantly higher SCV rate than that of patients having Lp-PLA2 ≤ 200 μg/L.

Conclusion

The admission Lp-PLA2 level might be a helpful predictor for SCV in aSAH.

CRP Albumin ratio is positively associated with poor outcome in patients with traumatic brain injury

OBJECTIVES

The C-reactive protein/albumin ratio (CAR), a novel inflammation-based index, has been proved useful in predicting outcome of various diseases. We designed this study to explore the prognostic value of CAR in patients with traumatic brain injury (TBI).

PATIENTS AND METHODS

We retrospectively included 151 patients diagnosed with TBI and collected related clinical and laboratory data. Univariate and multivariate logistic regression were conducted to find independent risk factors of mortality. Then, we incorporated CAR into prognostic model and drew receiver operating characteristic (ROC) curve of models. Finally, we compared the predictive value of different models by evaluating the area under the receiver operating characteristic curves (AUC).

RESULTS

In this study, a total of 54 patients had poor survival outcome with mortality rate of 35.8 %. Results of multivariate analysis showed that GCS score in admission (OR 0.700, 95 %Cl 0.570-0.860, p=0.001), acute kidney injury (AKI) (OR 3.952, 95Cl 1.631-9.577, p=0.002) and CAR (OR 1.202, 95Cl 1.039-1.390, p=0.013) were independently associated with in-hospital mortality. The AUC value of predictive model composed of the above three factors was higher than GCS or CAR alone.

CONCLUSION

CAR is an independent risk factor of mortality in patients with TBI. Incorporating CAR into predictive model could increase the value in predicting outcome of TBI patients.

Clinical usefulness of early serial measurements of C-reactive protein as outcome predictors in patients with subarachnoid hemorrhage

BACKGROUND

The purpose of this study was to evaluate the role of C-reactive protein (CRP) in predicting neurological outcomes of patients with subarachnoid hemorrhage (SAH).

METHODS

In this retrospective, observational study of adult patients with SAH treated between January 2012 and June 2017. Initial CRP levels collected within 24 h from the onset of SAH, the follow-up CRP levels were measured. The primary outcome was neurological status at six-month follow-up assessed with the Glasgow Outcome Scale (GOS, 1 to 5).

RESULTS

Among 156 patients with SAH, 145 (92.9%) survived until discharge. Of these survivors, 109 (69.9%) manifested favorable neurological outcomes (GOS of 4 or 5). Initial CRP levels on admission and maximal CRP levels within four days were significantly higher in the group with poor neurological outcome compared with those manifesting favorable neurological outcomes (P = 0.022, P < 0.001, respectively). However, the clearance of CRPs did not differ significantly between the two groups (P = 0.785). Analysis of the receiver operating characteristic curve for prediction of poor neurological outcome showed that the performance of the maximal CRP was significantly better compared with the initial CRP or the clearance of CRP (P = 0.007, P < 0.001, respectively). In this study, the effect of CRP on neurological outcomes differed according to surgical clipping. The maximal CRP levels within four days facilitate the prediction of neurological outcomes of SAH patients without surgical clipping (C-statistic: 0.856, 95% confidence interval [CI]: 0.767-0.921). However, they were poorly associated with neurological prognoses in SAH patients who underwent surgical clipping (C-statistic: 0.562, 95% CI: 0.399-0.716). Multivariable logistic regression analysis revealed that age (adjusted odds ratio [OR]: 1.10, 95% CI: 1.052-1.158), initial Glasgow Coma Scale (adjusted OR: 0.74, 95% CI: 0.647-0.837), and maximal CRP without surgical clipping (adjusted OR: 1.27, 95% CI: 1.066-1.516) were significantly associated with poor neurological outcomes in SAH patients.

CONCLUSIONS

Early serial measurements of CRP may be used to predict neurological outcomes of SAH patients. Furthermore, maximal CRP levels within four days post-SAH are significantly correlated with poor neurological outcomes.

Soluble ST2 Is Associated With New Epileptiform Abnormalities Following Nontraumatic Subarachnoid Hemorrhage

Background and Purpose- We evaluated the association between 2 types of predictors of delayed cerebral ischemia after nontraumatic subarachnoid hemorrhage, including biomarkers of the innate immune response and neurophysiologic changes on continuous electroencephalography. Methods- We studied subarachnoid hemorrhage patients that had at least 72 hours of continuous electroencephalography and blood samples collected within the first 5 days of symptom onset. We measured inflammatory biomarkers previously associated with delayed cerebral ischemia and functional outcome, including soluble ST2 (sST2), IL-6 (interleukin-6), and CRP (C-reactive protein). Serial plasma samples and cerebrospinal fluid sST2 levels were available in a subgroup of patients. Neurophysiologic changes were categorized into new or worsening epileptiform abnormalities (EAs) or new background deterioration. The association of biomarkers with neurophysiologic changes were evaluated using the Wilcoxon rank-sum test. Plasma and cerebrospinal fluid sST2 were further examined longitudinally using repeated measures mixed-effects models. Results- Forty-six patients met inclusion criteria. Seventeen (37%) patients developed new or worsening EAs, 21 (46%) developed new background deterioration, and 8 (17%) developed neither. Early (day, 0-5) plasma sST2 levels were higher among patients with new or worsening EAs (median 115 ng/mL [interquartile range, 73.8-197]) versus those without (74.7 ng/mL [interquartile range, 44.8-102]; P=0.024). Plasma sST2 levels were similar between patients with or without new background deterioration. Repeated measures mixed-effects modeling that adjusted for admission risk factors showed that the association with new or worsening EAs remained independent for both plasma sST2 (β=0.41 [95% CI, 0.09-0.73]; P=0.01) and cerebrospinal fluid sST2 (β=0.97 [95% CI, 0.14-1.8]; P=0.021). IL-6 and CRP were not associated with new background deterioration or with new or worsening EAs. Conclusions- In patients admitted with subarachnoid hemorrhage, sST2 level was associated with new or worsening EAs but not new background deterioration. This association may identify a link between a specific innate immune response pathway and continuous electroencephalography abnormalities in the pathogenesis of secondary brain injury after subarachnoid hemorrhage.

Mechanisms of neuroinflammation and inflammatory mediators involved in brain injury following subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disorder. Neuroinflammation is a critical cause of brain injury following SAH in both acute and chronic phases. While accumulating evidence has shown that therapies targeting neuroinflammation exerted beneficial effects in experimental SAH, there is little clinical evidence. One of the factors making neuroinflammation complicated is that inflammatory signaling pathways and mediators act as protective or detrimental responses at different phases. In addition, biomarkers to detect neuroinflammation are little known in clinical settings. In this review, first, we discuss how the inflammatory signaling pathways contribute to brain injury and other secondary pathophysiological changes in SAH. Damage-associated molecular patterns arising from mechanical stress, transient global cerebral ischemia, red blood cell breakdown and delayed cerebral ischemia following SAH trigger to activate pattern recognition receptors (PRRs) such as Toll-like receptors, nucleotide-binding oligomerization domain-like receptors, and receptors for advanced glycation end products. Most of PRRs activate common downstream signaling transcriptional factor nuclear factor-κΒ and mitogen-activated protein kinases, releasing pro-inflammatory mediators and cytokines. Next, we focus on how pro-inflammatory substances play a role during the course of SAH. Finally, we highlight an important inducer of neuroinflammation, matricellular protein (MCP). MCPs are a component of extracellular matrix and exert beneficial and harmful effects through binding to receptors, other matrix proteins, growth factors, and cytokines. Treatment targeting MCPs is being proved efficacious in pre-clinical models for preventing brain injury including neuroinflammation in SAH. In addition, MCPs may be a candidate of biomarkers predicting brain injury following SAH in clinical settings.

Chitinase-3-Like Protein 1, Serum Amyloid A1, C-Reactive Protein, and Procalcitonin Are Promising Biomarkers for Intracranial Severity Assessment of Traumatic Brain Injury: Relationship with Glasgow Coma Scale and Computed Tomography Volumetry

OBJECTIVE

The volume and location of intracranial hematomas are well-known prognostic factors for traumatic brain injury. The aim of this study was to determine the relationship of serum biomarkers S100β, glial fibrillary acidic protein, neuron-specific enolase, total tau, phosphorylated neurofilament heavy chain, serum amyloid A1 (SAA1), C-reactive protein, procalcitonin (PCT), and chitinase-3-like protein 1 (YKL-40) with traumatic brain injury severity and the amount and location of hemorrhagic traumatic lesions.

METHODS

A prospective observational cohort of 115 patients with a Glasgow Coma Scale (GCS) score of 3-15 were evaluated. Intracranial lesion volume was measured from the semiautomatic segmentation of hematoma on computed tomography using Analyze software. The establishment of possible biomarker cutoff points for intracranial lesion detection was estimated using the Youden Index (J) obtained from the area under the receiver operating characteristic curve.

RESULTS

SAA1, YKL-40, PCT, and S100β showed the most robust association with level of consciousness, both with total GCS and motor score. Biomarkers significantly correlated with volumetric measurements of subdural hematoma, traumatic subarachnoid hemorrhage, intraparenchymal hemorrhage, intraventricular hemorrhage, and total amount of bleeding. The type of intracranial hemorrhage was associated with various release patterns of neurobiochemical markers.

CONCLUSIONS

YKL-40, SAA1, C-reactive protein, and PCT combined with S100β were the most promising biomarkers to determine the presence, location, and extent of traumatic intracranial lesions. Combination of biomarkers further increased the discriminatory capacity for the detection of intracranial bleeding.

Plasma Levels of IL-6, IL-8, IL-10, ICAM-1, VCAM-1, IFNγ, and TNFα are not Associated with Delayed Cerebral Ischemia, Cerebral Vasospasm, or Clinical Outcome in Patients with Subarachnoid Hemorrhage

BACKGROUND

Delayed cerebral ischemia (DCI) is a serious and frequent complication following subarachnoid hemorrhage (SAH). The pathophysiology behind DCI remains poorly understood, but inflammation has been proposed to play a significant role. This study investigated the relationship between plasma levels of some of the most important inflammatory markers and DCI, cerebral vasospasm, and functional outcome in patients with SAH.

METHODS

In 90 patients with SAH, interleukin-6, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, high sensitivity C-reactive protein (HsCRP), interleukin-8, interleukin-10, interferon gamma, and tumor necrosis factor alpha were measured in peripheral blood day 3 and day 8 after SAH. Any occurrence of DCI or infection was recorded, and computed tomography angiography was performed on day 8. Clinical outcome was assessed after 3 months.

RESULTS

HsCRP on day 3 was higher in patients with angiographic vasospasm (P = 0.003), and HsCRP on day 8 was higher in patients with poor outcome (P = 0.014). No association with DCI, vasospasm, or outcome was found for any of the remaining analyzed substances.

CONCLUSIONS

High plasma levels of HsCRP were significantly associated with angiographic vasospasm and clinical outcome. Plasma levels of interleukin-6, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, interleukin-8, interleukin-10, interferon gamma, and tumor necrosis factor alpha were not associated with DCI, angiographic vasospasm, or clinical outcome at 3 months.

Serum Glucose and Potassium Ratio as Risk Factors for Cerebral Vasospasm after Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

Cerebral vasospasm is associated with poor prognosis in patients with aneurysmal subarachnoid hemorrhage (SAH), and biomarkers for predicting poor prognosis have not yet been established. We attempted to clarify the relationship between serum glucose/potassium ratio and cerebral vasospasm in patients with aneurysmal SAH.

METHODS

We studied 333 of 535 aneurysmal SAH patients treated between 2006 and 2016 (123 males, 210 females; mean age 59.7 years; range 24-93). We retrospectively analyzed the relationship between cerebral vasospasm grade and clinical risk factors, including serum glucose/potassium ratio.

RESULTS

Postoperative angiography revealed cerebral vasospasm in 112 patients (33.6%). Significant correlations existed between the ischemic complication due to cerebral vasospasm and glucose/potassium ratio (P < .0001), glucose (P = .016), and potassium (P = .0017). Serum glucose/potassium ratio was elevated in the cerebral vasospasm grade dependent manner (Spearman's r = 0.1207, P = .0279). According to the Glasgow Outcome Scale (GOS) score at discharge, 185 patients (55.5%) had a poor outcome (GOS scores 1-3). Serum glucose/potassium ratio was significantly correlated between poor outcome (GOS scores 1-3) and age (P < .0001), serum glucose/potassium ratio (P < .0001), glucose (P < .0001), potassium (P = .0004), white blood cell count (P = .0012), and cerebral infarction due to cerebral vasospasm (P < .0001). Multivariate logistic regression analyzes showed significant correlations between cerebral infarction due to cerebral vasospasm and serum glucose/potassium ratio (P = .018), glucose (P = .027), and potassium (P = .052).

CONCLUSIONS

Serum glucose/potassium ratio in cases of aneurysmal SAH was significantly associated with cerebral infarction due to cerebral vasospasm and GOS at discharge. Therefore, this factor was useful to predict prognosis in patients with cerebral vasospasm and aneurysmal SAH.

Red Cell Distribution Width After Subarachnoid Hemorrhage

BACKGROUND

High red cell distribution width (RDW) values have been associated with increased hospital mortality in critically ill patients, but few data are available for subarachnoid hemorrhage (SAH).

METHODS

We analyzed an institutional database of adult (>18 y) patients admitted to the Department of Intensive Care after nontraumatic SAH between January 2011 and May 2016. RDW (normal value, 10.9% to 13.4%) was obtained daily from admission for a maximum of 7 days, from routine blood analysis. We recorded the occurrence of delayed cerebral ischemia (DCI), and neurological outcome (assessed using the Glasgow Outcome Scale [GOS]) at 3 months.

RESULTS

A total of 270 patients were included (median age 54 y-121/270 male [45%]), of whom 96 (36%) developed DCI and 109 (40%) had an unfavorable neurological outcome (GOS, 1 to 3). The median RDW on admission was 13.8 [13.3 to 14.5]% and the highest value during the intensive care unit (ICU) stay 14.2 [13.6 to 14.8]%. The RDW was high (>13.4%) in 177 patients (66%) on admission and in 217 (80%) at any time during the ICU stay. Patients with a high RDW on admission were more likely to have an unfavorable neurological outcome. In multivariable regression analysis, older age, a high WFNS grade on admission, presence of DCI or intracranial hypertension, previous neurological disease, vasopressor therapy and a high RDW (OR, 1.1618 [95% CI, 1.213-2.158]; P=0.001) during the ICU stay were independent predictors of unfavorable neurological outcome.

CONCLUSIONS

High RDW values were more likely to result in an unfavorable outcome after SAH. This information could help in the stratification of SAH patients already on ICU admission.

The role of inflammation and potential use of sex steroids in intracranial aneurysms and subarachnoid hemorrhage

Background

Aneurysmal subarachnoid hemorrhage (aSAH) continues to be a devastating neurological condition with a high risk of associated morbidity and mortality. Inflammation has been shown to increase the risk of complications associated with aSAH such as vasospasm and brain injury in animal models and humans. The goal of this review is to discuss the inflammatory mechanisms of aneurysm formation, rupture and vasospasm and explore the role of sex hormones in the inflammatory response to aSAH.

Methods

A literature review was performed using PubMed using the following search terms: "intracranial aneurysm," "cerebral aneurysm," "dihydroepiandrosterone sulfate" "estrogen," "hormone replacement therapy," "inflammation," "oral contraceptive," "progesterone," "sex steroids," "sex hormones" "subarachnoid hemorrhage," "testosterone." Only studies published in English language were included in the review.

Results

Studies have shown that administration of sex hormones such as progesterone and estrogen at early stages in the inflammatory cascade can lower the risk and magnitude of subsequent complications. The exact mechanism by which these hormones act on the brain, as well as their role in the inflammatory cascade is not fully understood. Moreover, conflicting results have been published on the effect of hormone replacement therapy in humans. This review will scrutinize the variations in these studies to provide a more detailed understanding of sex hormones as potential therapeutic agents for intracranial aneurysms and aSAH.

Conclusion

Inflammation may play a role in the pathogenesis of intracranial aneurysm formation and subarachnoid hemorrhage, and administration of sex hormones as anti-inflammatory agents has been associated with improved functional outcome in experimental models. Further studies are needed to determine the therapeutic role of these hormones in the intracranial aneurysms and aSAH.

Neurocognitive outcomes after aneurysmal subarachnoid hemorrhage: Identifying inflammatory biomarkers

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe type of stroke which carries a high case-fatality rate. Those who survive the ictus of aneurysm rupture harbor substantial risks of neurological morbidity, functional disability, and cognitive dysfunction. Although the pervasiveness of cognitive impairment is widely acknowledged as a long-term sequela of aSAH, the mechanisms underlying its development are poorly understood. The onset of aSAH elicits activation of the inflammatory cascade, and ongoing neuroinflammation is suspected to contribute to secondary complications, such as vasospasm and delayed cerebral ischemia. In this review, we analyze the extant literature regarding the relationship between neuroinflammation and cognitive dysfunction after aSAH. Pro-inflammatory cytokines appear to play a role in maintaining normal cognitive function in adults unaffected by aSAH. However, in the setting of aSAH, elevated cytokine levels may correlate with worse neuropsychological outcomes. This seemingly dichotomous relationship between neuroinflammation and cognition suggests that the action of cytokines varies, depending on their physiologic environment. Experimental therapies which suppress the immune response to aSAH appear to have a beneficial effect on cognitive outcomes. However, further studies are necessary to determine the utility of inflammatory mediators as biomarkers of neurocognitive outcomes, as well as their role in the management of aSAH.

Vascular diseases and bleedings

Diseases of the central nervous system that are caused by an underlying vascular pathology typically result in either hemorrhage or ischemia. Most prominent entities include spontaneous subarachnoid hemorrhage, spontaneous intracerebral hemorrhage, and ischemic stroke. For anatomic reasons, cerebrospinal fluid (CSF) qualifies as body fluid for the exploration of biomarkers in these disorders. Even though in subarachnoid hemorrhage a few CSF parameters have been established for routine diagnostic purposes, there is still an unmet need and broad interest in the identification of molecules that would allow further insight into disease mechanisms and supplement patients' medical care. This chapter provides an overview on what is presently known about CSF biomarkers in spontaneous subarachnoid hemorrhage, spontaneous intracerebral hemorrhage, and ischemic stroke. We recapitulate current evidence on established diagnostic tests, discuss the role of various CSF molecules in the pathophysiology of these diseases, and illuminate their potential use in future clinical practice. Furthermore, we address methodologic aspects as well as shortcomings of research in this field.

Hypothesis on the Role of Cryptochromes in Inflammation and Subarachnoid Hemorrhage Outcome

We have recently found that the temperature variability (TV) in the day-night cycle may predict the mean intracranial pressure in the following 24 h (ICP₂₄) in subarachnoid hemorrhage (SAH) patients under multimodality monitoring, sedation, and hypothermia (<35°C). Specifically, we found that ICP₂₄ = 6 (4 - TV) mmHg. TV is the ratio between the coefficient of variation of temperature during the nocturnal and the preceding diurnal periods. This result suggests that the circadian clock reflects brain plasticity mechanisms and its malfunctioning leads to deterioration of the neurologic status. The sleep-wake cycle is absent in these patients and their circadian clock can function properly only by environment light-independent mechanisms. One mechanism involves the circadian clock proteins named cryptochromes (CRYs). CRYs are highly preserved and widespread in the evolutionary tree, are expressed in different cell types in humans [type II CRYs, in two forms: human cryptochrome 1 and 2 (hCRY1 and hCRY2)], and in certain species, respond to blue light and play role in magnetoreception. Interestingly, SAH outcome seems to correlate with inflammation, and CRYs decrease inflammatory activity. Our hypothesis derived from these observations is that CRYs modulate the circadian oscillation of temperature even during therapeutic hypothermia and improve outcome in SAH through decrease in inflammation. A strategy to test this hypothesis is to measure periodically during the acute phase of high-grade SAH the level of CRYs in cerebrospinal fluid (CSF) and circulating white blood cells, and to correlate these levels with outcome, TV, ICP₂₄, and pro- and anti-inflammatory markers in CSF and blood. If this hypothesis is true, the development of therapies targeting inflammation in SAH could take advantage of cryptochrome properties. It has been shown that blue light phototherapy increases the expression of CRYs in blood mononuclear cells in jaundiced neonates. Likewise, visual stimulus with flashing light improves Alzheimer's disease features in experimental model and there is a prominent expression of CRYs in the retina. Remarkably, recent evidence showed that hCRY2 responds to electromagnetic fields, which could be one elusive mechanism of action of transcranial magnetic stimulation and a reason for its use in SAH.

Inhibition of myeloid differentiation primary response protein 88 provides neuroprotection in early brain injury following experimental subarachnoid hemorrhage

Accumulating of evidence suggests that activation of nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) exacerbates early brain injury (EBI) following subarachnoid hemorrhage (SAH) by provoking pro-inflammatory and pro-apoptotic signaling. Myeloid differentiation primary response protein 88 (MyD88) is an endogenous adaptor protein in the toll-like receptors (TLRs) and interleukin (IL) -1β family signaling pathways and acts as a bottle neck in the NF-κB and MAPK pathways. Here, we used ST2825, a selective inhibitor of MyD88, to clarify whether inhibiting MyD88 could provide neuroprotection in EBI following SAH. Our results showed that the expression of MyD88 was markedly increased at 24 h post SAH. Intracerebroventricular injection of ST2825 significantly reduced the expression of MyD88 at 24 h post SAH. Involvement of MAPKs and NF-κB signaling pathways was revealed that ST2825 inhibited SAH-induced phosphorylation of TAK1, p38 and JNK, the nuclear translocation of NF-κB p65, and degradation of IκBα. Further, ST2825 administration diminished the SAH-induced inflammatory response and apoptosis. As a result, SAH-induced EBI was alleviated and neurological deficits caused by SAH were reversed. Our findings suggest that MyD88 inhibition confers marked neuroprotection against EBI following SAH. Therefore, MyD88 might be a promising new molecular target for the treatment of SAH.

Serum glucose/potassium ratio as a clinical risk factor for aneurysmal subarachnoid hemorrhage

OBJECTIVE

Aneurysmal subarachnoid hemorrhage (SAH) can result in poor outcomes, and biomarkers for predicting poor prognosis have not yet been established. The aim of this study was to clarify the significance of the serum glucose/potassium ratio for predicting the prognosis of aneurysmal SAH.

METHODS

The authors retrospectively reviewed the records of 565 patients with aneurysmal SAH between 2006 and 2016. The patient group comprised 208 men and 357 women (mean age 61.5 years, range 10-95 years). A statistical analysis was conducted of the clinical and laboratory risk factors of poor outcome, including the serum glucose/potassium ratio.

RESULTS

On estimation of the initial assessment using Hunt and Kosnik (H-K) grading, 233 patients (41.2%) were classified as the severe SAH group (H-K Grade IV or V). There were significant correlations between the severe SAH group and serum glucose/potassium ratio (p < 0.0001). Serum glucose/potassium ratio was elevated in an H-K grade-dependent manner (Spearman's r = 0.5374, p < 0.0001). With the estimation of the Glasgow Outcome Scale (GOS) score at discharge, 355 patients (62.8%) were classified as poor outcome (GOS score 1-3). The serum glucose/potassium ratio was elevated in a GOS score at discharge-dependent manner (Spearman's r = 0.4006, p < 0.0001), and was significantly elevated in the poor outcome group compared with the good outcome group (GOS score 4 or 5; p = 0.0245). There were significant correlations between poor outcome and serum glucose/potassium ratio (p < 0.0001), age (p < 0.0001), brain natriuretic peptide levels (p = 0.011), cerebral infarction due to vasospasm (p < 0.0001), and H-K grade (p < 0.0001). Multivariate logistic regression analyses showed significant correlations between poor outcome and serum glucose/potassium ratio (p = 0.009).

CONCLUSIONS

In this study, the serum glucose/potassium ratio of patients with aneurysmal SAH at admission was significantly correlated with H-K grade and GOS score at discharge. Therefore, this ratio was useful for predicting prognosis of aneurysmal SAH, especially in severe cases.

Early Diagnosis of Delayed Cerebral Ischemia: Possible Relevance for Inflammatory Biomarkers in Routine Clinical Practice?

BACKGROUND

Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) is one of the main causes of neurologic deterioration. However, it frequently evades timely detection. Early identification and effective reversal may improve the clinical outcome. In this prospective study, we evaluate several serum inflammatory markers after aneurysmal SAH with regard to the occurrence of DCI.

METHODS

On days 1, 4, 7, 10, and 14 after SAH, leucocyte count, C-reactive protein, interleukin 6, E-selectin, matrix metallopeptidase 9, intercellular adhesion molecule 1, and leukemia inhibitory factor were assessed in patients' serum samples. Using a Cox regression model (SPSS 21.0), associations of baseline parameters, maximum and delta (maximum minus baseline) values with occurrence of DCI were evaluated.

RESULTS

Considering the assessed parameters, leucocyte count (high baseline and delta values) matches most closely with occurrence of DCI. Although baseline levels of C-reactive protein are also associated with occurrence of DCI, neither maximum (only on a borderline level) nor delta levels do so.

CONCLUSIONS

Our data analysis identified leucocyte count as the parameter most likely associated with occurrence of DCI. However, because of its lack of specificity leucocyte count, it cannot be used as a biomarker. As hypothesized earlier, the results indicate a possible involvement of the inflammatory reaction after aneurysmal SAH in the pathomechanism of DCI.

Radiodensity of intraventricular hemorrhage associated with aneurysmal subarachnoid hemorrhage may be a negative predictor of outcome

OBJECTIVE The presence, extent, and distribution of intraventricular hemorrhage (IVH) have been associated with negative outcomes in aneurysmal subarachnoid hemorrhage (SAH). Several qualitative scores (Fisher grade, LeRoux score, and Graeb score) have been established for evaluating SAH and IVH. However, no study has assessed the radiodensity within the ventricular system in aneurysmal SAH patients with IVH. Prior studies have suggested that hemorrhage with a higher radiodensity, as measured by CT Hounsfield units, can cause more irritation to brain parenchyma. Therefore, the authors set out to investigate the relationship between the overall radiodensity of the ventricular system in aneurysmal SAH patients with IVH and their clinical outcome scores. METHODS The authors reviewed the records of 101 patients who were admitted to their institution with aneurysmal SAH and IVH between January 2011 and July 2015. The following data were collected: age, sex, Glasgow Coma Scale (GCS) score, Hunt and Hess grade, extent of SAH (none, thin, or thick/localized), aneurysm location, and Glasgow Outcome Scale (GOS) score. To evaluate the ventricular radiodensity, the initial head CT scan was loaded into OsiriX MD. The ventricular system was manually selected as the region of interest (ROI) through all pertinent axial slices. After this, an averaged ventricular radiodensity was calculated from the ROI by the software. GOS scores were dichotomized as 1-3 and 4-5 subgroups for analysis. RESULTS On univariate analysis, younger age, higher GCS score, lower Hunt and Hess grade, and lower ventricular radiodensity significantly correlated with better GOS scores (all p < 0.05). Subsequent multivariate analysis yielded age (OR 0.936, 95% CI 0.895-0.979), GCS score (OR 3.422, 95% CI 1.9-6.164), and ventricular density (OR 0.937, 95% CI 0.878-0.999) as significant independent predictors (p < 0.05). A receiver operating characteristic curve yielded 12.7 HU (area under the curve 0.625, p = 0.032, sensitivity = 0.591, specificity = 0.596) as threshold between GOS scores of 1-3 and 4-5. CONCLUSIONS This study suggests that the ventricular radiodensity in aneurysmal SAH patients with IVH, along with GCS score and age, may serve as a predictor of clinical outcome.

Neuroinflammation responses after subarachnoid hemorrhage: A review

Subarachnoid hemorrhage (SAH) is an important cause of stroke mortality and morbidity, especially in the young stroke population. Recent evidences indicate that neuroinflammation plays a critical role in both early brain injury and the delayed brain deterioration after SAH, including cellular and molecular components. Cerebral vasospasm (CV) can lead to death after SAH and independently correlated with poor outcome. Neuroinflammation is evidenced to contribute to the etiology of vasospasm. Besides, systemic inflammatory response syndrome (SIRS) commonly occurs in the SAH patients, with the presence of non-infectious fever and systematic complications. In this review, we summarize the evidences that indicate the prominent role of inflammation in the pathophysiology of SAH. That may provide the potential implications on diagnostic and therapeutic strategies.

An introduction to the pathophysiology of aneurysmal subarachnoid hemorrhage

Pathophysiological processes following subarachnoid hemorrhage (SAH) present survivors of the initial bleeding with a high risk of morbidity and mortality during the course of the disease. As angiographic vasospasm is strongly associated with delayed cerebral ischemia (DCI) and clinical outcome, clinical trials in the last few decades focused on prevention of these angiographic spasms. Despite all efforts, no new pharmacological agents have shown to improve patient outcome. As such, it has become clear that our understanding of the pathophysiology of SAH is incomplete and we need to reevaluate our concepts on the complex pathophysiological process following SAH. Angiographic vasospasm is probably important. However, a unifying theory for the pathophysiological changes following SAH has yet not been described. Some of these changes may be causally connected or present themselves as an epiphenomenon of an associated process. A causal connection between DCI and early brain injury (EBI) would mean that future therapies should address EBI more specifically. If the mechanisms following SAH display no causal pathophysiological connection but are rather evoked by the subarachnoid blood and its degradation production, multiple treatment strategies addressing the different pathophysiological mechanisms are required. The discrepancy between experimental and clinical SAH could be one reason for unsuccessful translational results.

Early Predictors of Fever in Patients with Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Fever is commonly observed in patients who have had aneurysmal subarachnoid hemorrhage (SAH), and it has been associated with the occurrence of delayed cerebral ischemia and worse outcomes in previous studies. Frequently, fever is not the result of bacterial infections, and distinction between infection-related fever and fever secondary to brain injury (also referred as central fever) can be challenging.

OBJECTIVES

The current study aimed to identify risk factors on admission for the development of central fever in patients with SAH.

METHODS

Databank analysis was performed using information from demographic data (age, gender), imaging (transcranial Doppler ultrasound, computed tomography, and cerebral angiogram), laboratory (white blood cell count, hemoglobin, renal function, and electrolytes), and clinical assessment (Hunt-Hess and modified Fisher scales on admission, occurrence of fever). A multivariate logistic regression model was created.

RESULTS

Of 55 patients, 32 developed fever during the first 7 days of hospital stay (58%). None of the patients had identifiable bacterial infections during their first week in the neurocritical care unit. Hunt-Hess scale >2 and leukocytosis on admission were associated to the development of central fever, even after correction in a logistic regression model.

CONCLUSION

Leukocytosis and a poor neurologic examination on admission might help predict which subset of patients with SAH are at higher risk of developing central fever early in their hospital stay.

Elevated Baseline C-Reactive Protein as a Predictor of Outcome After Aneurysmal Subarachnoid Hemorrhage: Data From the Simvastatin in Aneurysmal Subarachnoid Hemorrhage (STASH) Trial

There remains a proportion of patients with unfavorable outcomes after aneurysmal subarachnoid hemorrhage, of particular relevance in those who present with a good clinical grade. A forewarning of those at risk provides an opportunity towards more intensive monitoring, investigation, and prophylactic treatment prior to the clinical manifestation of advancing cerebral injury.

Impact of Early Leukocytosis and Elevated High-Sensitivity C-Reactive Protein on Delayed Cerebral Ischemia and Neurologic Outcome After Subarachnoid Hemorrhage

BACKGROUND

The role of inflammatory response in the pathophysiology of subarachnoid hemorrhage (SAH) is being increasingly recognized. This study analyzed the impact of cellular and biochemical markers of early inflammatory response to ictus on outcome after SAH.

METHODS

Patients with SAH were prospectively studied for markers of early cellular, biochemical, and cytotoxic inflammatory response, including total leukocyte count (TLC), high-sensitivity C-reactive protein (hs-CRP), and lactate dehydrogenase. The relationship of these markers to delayed cerebral ischemia (DCI), new infarct, and Glasgow Outcome Scale (GOS) score at 3 months was studied.

RESULTS

The study comprised 246 patients. Of patients, 94 who developed DCI had a significantly higher TLC [± SD] (11.2 × 10(3)/mm(3) [± 4.0] vs. 9.4 × 10(3)/mm(3) [± 2.9], P = 0.001) and 62 with new infarct had significantly higher TLC (11.0 × 10(3)/mm(3) [± 3.6] vs. 9.8 × 10(3)/mm(3) [± 3.4], P = 0.05). GOS score had a significant inverse relationship to TLC at admission. The mean TLC [± SD] was 12.7 × 10(3)/mm(3) [± 4.2], 11.7 × 10(3)/mm(3) [± 3.1], 10.2 × 10(3)/mm(3) [± 3.4], and 9.3 × 10(3)/mm(3) [± 2.8] among patients with GOS scores of 1, 3, 4, and 5 (P < 0.001). hs-CRP showed a trend of an inverse relationship to GOS score in univariate analysis. Lactate dehydrogenase had no relationship with any outcome parameter. In multivariate analysis, higher admission TLC had a significant association with DCI (P = 0.01) and poorer GOS score (P < 0.001), and higher hs-CRP had a significant association with poorer GOS score (P = 0.05).

CONCLUSIONS

A leukocytosis response to ictus seems to have a significant independent association with both DCI and poor GOS score, and hs-CRP level had a significant independent association with poor GOS score, indicating preeminence of early cellular response in SAH pathophysiology.

Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (SAH) is a worldwide health burden with high fatality and permanent disability rates. The overall prognosis depends on the volume of the initial bleed, rebleeding, and degree of delayed cerebral ischemia (DCI). Cardiac manifestations and neurogenic pulmonary edema indicate the severity of SAH. The International Subarachnoid Aneurysm Trial (ISAT) reported a favorable neurological outcome with the endovascular coiling procedure compared with surgical clipping at the end of 1 year. The ISAT trial recruits were primarily neurologically good grade patients with smaller anterior circulation aneurysms, and therefore the results cannot be reliably extrapolated to larger aneurysms, posterior circulation aneurysms, patients presenting with complex aneurysm morphology, and poor neurological grades. The role of hypothermia is not proven to be neuroprotective according to a large randomized controlled trial, Intraoperative Hypothermia for Aneurysms Surgery Trial (IHAST II), which recruited patients with good neurological grades. Patients in this trial were subjected to slow cooling and inadequate cooling time and were rewarmed rapidly. This methodology would have reduced the beneficial effects of hypothermia. Adenosine is found to be beneficial for transient induced hypotension in 2 retrospective analyses, without increasing the risk for cardiac and neurological morbidity. The neurological benefit of pharmacological neuroprotection and neuromonitoring is not proven in patients undergoing clipping of aneurysms. DCI is an important cause of morbidity and mortality following SAH, and the pathophysiology is likely multifactorial and not yet understood. At present, oral nimodipine has an established role in the management of DCI, along with maintenance of euvolemia and induced hypertension. Following SAH, hypernatremia, although less common than hyponatremia, is a predictor of poor neurological outcome.

In-hospital C-reactive protein predicts outcome after aneurysmal subarachnoid haemorrhage treated by endovascular coiling

BACKGROUND

This study aimed to examine prospectively whether the inflammatory marker C-reactive protein (CRP) increases in patients with aneurysmal subarachnoid haemorrhage (aSAH) treated by endovascular coiling and investigate whether CRP could be used as prognostic factor for long-term neurological outcome.

METHODS

This single-hospital study comprised 98 consecutive patients with confirmed aSAH treated by endovascular coiling. Admission status was classified according to the World Federation of Neurosurgical Societies (WFNS) Scale and initial cerebral computed tomography according to Fisher scale. CRP was analysed on days 0, 1, 2, 3, 4, 6 and 8 after the initial bleed. A neurological follow up was performed 1 year later according to the Extended Glasgow Outcome Scale (GOSE) for overall outcome and National Institute of Health Stroke Scale (NIHSS) for focal deficit.

RESULTS

CRP values increased from normal to peak at 53 mg/l at day 3-4 and then declined, without normalising, at day 8. Patients with a higher increase in CRP had a poorer neurological outcome after 1 year. CRP during the first week had a stronger correlation to outcome (r = 0.417) and NIHSS (r = 0.449) than initial clinical status (WFNS; r = 0.280 and 0.274) and radiology (Fisher scale; r = 0.137 and 0.158). CRP increase indicated a risk of poor outcome (GOSE) (P < 0.001) and permanent loss of neurological function (NIHSS) (P < 0.001). Logistic regression analysis suggested that elevated CRP already on day 2 is an independent prognostic marker for outcome.

CONCLUSION

Early CRP values can perhaps be used as a prognostic factor for long-term neurological outcome prediction after endovascular treatment of aSAH.

Effects of intravenous infusion of hydrogen-rich fluid combined with intra-cisternal infusion of magnesium sulfate in severe aneurysmal subarachnoid hemorrhage: study protocol for a randomized controlled trial

Background

The failures of recent studies intended to prevent cerebral vasospasm have moved the focus of research into delayed cerebral ischemia away from cerebral artery constriction towards other mechanisms. Recent accumulating evidence has suggested that early brain injury is also involved in the development of delayed cerebral ischemia, and that hydrogen can prevent early brain injury. Therefore, we have established a combination therapy of intravenous hydrogen infusion and intra-cisternal magnesium sulfate infusion for the treatment of both early brain injury and cerebral vasospasm. The present randomized controlled clinical trial is designed to investigate the effects of this novel therapeutic strategy on the occurrence of cerebral vasospasm, delayed cerebral ischemia, and clinical outcomes after high-grade subarachnoid hemorrhage.

Methods

This study is a randomized, double-blind, placebo-controlled design to be conducted in two hospitals. A total of 450 patients with high-grade subarachnoid hemorrhage will be randomized to one of three arms: (i) Mg + H₂ group, (ii) Mg group, and (iii) control group. Patients who are assigned to the Mg + H₂ group will receive intra-cisternal magnesium sulfate infusion (2.5 mmol/L) at 20 mL/h for 14 days and intravenous hydrogen-rich fluid infusion (200 mL) twice a day for 14 days. Patients who are assigned to the Mg group will receive intra-cisternal magnesium sulfate infusion (2.5 mmol/L) at 20 mL/h for 14 days and intravenous normal glucose-electrolyte solution (200 mL) without added hydrogen twice a day for 14 days. Patients who are assigned to the control group will receive intra-cisternal Ringer solution without magnesium sulfate at 20 mL/h for 14 days and intravenous normal glucose-electrolyte solution (200 mL) without added hydrogen twice a day for 14 days. Primary outcome measures will be occurrence of delayed cerebral ischemia and cerebral vasospasm. Secondary outcome measures will be modified Rankin scale score at 3, 6, and 12 months and biochemical markers.

Discussion

The present protocol for a randomized, placebo-controlled study of intravenous hydrogen therapy with intra-cisternal magnesium infusion is expected to establish the efficacy and safety of this therapeutic strategy.

Trial registration

UMIN-CTR: UMIN000014696

Serum amyloid A is increased in children with abusive head trauma: a gel-based proteomic analysis

BACKGROUND

Abusive head trauma (AHT) is the leading cause of death from traumatic brain injury in infants and young children. Identification of mild AHT (Glasgow Coma Scale score: 13-15) is difficult because children can present with nonspecific symptoms and with no history of trauma.

METHODS

Two-dimensional difference gel electrophoresis combined with mass spectrometry was used to compare the serum protein profile of children with mild AHT and age-matched controls. Protein changes were confirmed by western blots. Western blots were performed using serum from children with mild, moderate, and severe AHT to assess the effect of injury severity on protein intensity. The protein identified--serum amyloid A (SAA)--was then measured by enzyme-linked immunosorbent assay.

RESULTS

Using serum from 18 mild AHT cases and 20 controls, there were ~1,000 protein spots; 2 were significantly different between groups. Both spots were identified as SAA. There was no relationship between protein levels and injury severity. SAA concentrations measured by enzyme-linked immunosorbent assay were increased in cases vs. controls.

CONCLUSION

SAA may be a potential biomarker to identify children with mild AHT who present for medical care without a history of trauma and who might otherwise not be recognized as needing a head computed tomography.

To look beyond vasospasm in aneurysmal subarachnoid haemorrhage

Delayed cerebral vasospasm has classically been considered the most important and treatable cause of mortality and morbidity in patients with aneurysmal subarachnoid hemorrhage (aSAH). Secondary ischemia (or delayed ischemic neurological deficit, DIND) has been shown to be the leading determinant of poor clinical outcome in patients with aSAH surviving the early phase and cerebral vasospasm has been attributed to being primarily responsible. Recently, various clinical trials aimed at treating vasospasm have produced disappointing results. DIND seems to have a multifactorial etiology and vasospasm may simply represent one contributing factor and not the major determinant. Increasing evidence shows that a series of early secondary cerebral insults may occur following aneurysm rupture (the so-called early brain injury). This further aggravates the initial insult and actually determines the functional outcome. A better understanding of these mechanisms and their prevention in the very early phase is needed to improve the prognosis. The aim of this review is to summarize the existing literature on this topic and so to illustrate how the presence of cerebral vasospasm may not necessarily be a prerequisite for DIND development. The various factors determining DIND that worsen functional outcome and prognosis are then discussed.

Biomarkers and acute brain injuries: interest and limits

For patients presenting with acute brain injury (such as traumatic brain injury, subarachnoid haemorrhage and stroke), the diagnosis and identification of intracerebral lesions and evaluation of the severity, prognosis and treatment efficacy can be challenging. The complexity and heterogeneity of lesions after brain injury are most probably responsible for this difficulty. Patients with apparently comparable brain lesions on imaging may have different neurological outcomes or responses to therapy. In recent years, plasmatic and cerebrospinal fluid biomarkers have emerged as possible tools to distinguish between the different pathophysiological processes. This review aims to summarise the plasmatic and cerebrospinal fluid biomarkers evaluated in subarachnoid haemorrhage, traumatic brain injury and stroke, and to clarify their related interests and limits for diagnosis and prognosis. For subarachnoid haemorrhage, particular interest has been focused on the biomarkers used to predict vasospasm and cerebral ischaemia. The efficacy of biomarkers in predicting the severity and outcome of traumatic brain injury has been stressed. The very early diagnostic performance of biomarkers and their ability to discriminate ischaemic from haemorrhagic stroke were studied.