Clinical Relevance of Changes in Peripheral Blood Cells After Intracranial Aneurysm Rupture

The association between systemic immune-inflammation index and the short-term functional outcome of patients with aneurysmal subarachnoid hemorrhage: a meta-analysis

Systemic immune-inflammation index (SII), calculated as platelet count × neutrophil count/lymphocyte count, is a novel biomarker reflecting immune and inflammatory responses. Its prognostic value in patients with subarachnoid hemorrhage (SAH) remains unclear. This meta-analysis aimed to evaluate the association between SII at admission and the short-term functional outcomes of patients with SAH. A systematic search of PubMed, Embase, Web of Science, China National Knowledge Infrastructure, and Wanfang databases identified cohort studies reporting the relationship between SII levels and functional outcomes in SAH. Poor functional outcomes were defined as modified Rankin Scale > 2 or Glasgow Outcome Scale < 4. Heterogeneity was assessed using I² statistic, and data synthesis was performed using a random-effects model by incorporating the influence of heterogeneity. RevMan 5.1 and Stata 17.0 were used for the analyses. Ten cohort studies involving 2,228 patients were included. Meta-analysis revealed that a high SII at admission significantly increased the risk of poor functional outcomes (OR: 3.08, 95% CI: 2.07-4.59, p < 0.001) with moderate heterogeneity (I² = 61%). Subgroup analysis showed a stronger association in studies with SII cutoffs ≥ 1400 compared to < 1400 (p for subgroup difference < 0.001). Meta-regression identified the cutoff value for SII as a significant modifier (p = 0.03) for the association between SII and poor functional outcome. Sensitivity analyses by excluding one dataset at a time showed similar results (p all < 0.05). In conclusion, elevated SII at admission is associated with an increased risk of poor short-term functional outcomes in SAH. These findings highlight SII as a potential prognostic biomarker for early risk stratification in SAH patients.

Regulatory T Cell- and Natural Killer Cell-Mediated Inflammation, Cerebral Vasospasm, and Delayed Cerebral Ischemia in Aneurysmal Subarachnoid Hemorrhage-A Systematic Review and Meta-Analysis Approach

Aneurysmal subarachnoid hemorrhage (SAH) involves a significant influx of blood into the cerebrospinal fluid, representing a severe form of stroke. Despite advancements in aneurysm closure and neuro-intensive care, outcomes remain impaired due to cerebral vasospasm and delayed cerebral ischemia (DCI). Previous pharmacological therapies have not successfully reduced DCI while improving overall outcomes. As a result, significant efforts are underway to better understand the cellular and molecular mechanisms involved. This review focuses on the activation and effects of immune cells after SAH and their interactions with neurotoxic and vasoactive substances as well as inflammatory mediators. Particular attention is given to clinical studies highlighting the roles of natural killer (NK) cells and regulatory T cells (Treg) cells. Alongside microglia, astrocytes, and oligodendrocytes, NK cells and Treg cells are key contributors to the inflammatory cascade following SAH. Their involvement in modulating the neuro-inflammatory response, vasospasm, and DCI underscores their potential as therapeutic targets and prognostic markers in the post-SAH recovery process. We conducted a systematic review on T cell- and natural killer cell-mediated inflammation and their roles in cerebral vasospasm and delayed cerebral ischemia. We conducted a meta-analysis to evaluate outcomes and mortality in studies focused on NK cell- and T cell-mediated mechanisms.

Treatment of hidradenitis suppurativa with adalimumab in the PIONEER I and II randomized controlled trials reduced indices of systemic inflammation, recognized risk factors for cardiovascular disease

BACKGROUND

Hidradenitis suppurativa (HS) is associated with increased cardiovascular disease (CVD) risk. Systemic immune inflammation index (SII), neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) are biomarkers of systemic inflammation and CVD. One small study identified a lower NLR and PLR in patients treated with adalimumab (ADA).

OBJECTIVES

To assess changes in SII, NLR, PLR and MLR in a larger cohort and to evaluate their association with disease severity and treatment response.

METHODS

This was a post hoc analysis of PIONEER I (ClinicalTrials.gov ID: NCT01468207) and PIONEER II (ClinicalTrials.gov ID: NCT01468233), two phase III randomized placebo-controlled clinical trials of ADA for HS. SII, NLR, PLR and MLR were log10-transformed and a linear mixed model was used to estimate the treatment effect.

RESULTS

SII, NLR, PLR and MLR decreased from baseline levels with ADA treatment by week 12, when the primary response endpoint was assessed. Significant changes first appeared at week 4 and were maintained to week 36. In contrast, no significant changes were observed in placebo-treated patients. In patients re-randomized at week 12 from placebo to ADA, SII, NLR, PLR and MLR also reduced within 4 weeks. In patients re-randomized from ADA to placebo, these biomarkers returned to baseline by week 36. In addition, SII, NLR and PLR correlated with draining fistula count (r = 0.26-0.43, P < 0.001). ADA nonresponders in PIONEER I had a higher SII, NLR and PLR at baseline and week 12, but this change did not achieve statistical significance when draining fistulae were adjusted for.

CONCLUSIONS

Treatment of patients with HS with ADA resulted in rapid sustained reduction in systemic inflammation, measured by the biomarkers SII, NLR, PLR and MLR, which correlate with CVD risk. SII, NLR and PLR may predict ADA response, although this may be dependent on their interaction with the number of draining fistulae.

Developmental endothelial locus-1 as a potential biomarker for the formation and progression of intracranial aneurysm

BACKGROUND

Intracranial aneurysms (IAs) are pathological dilations occurring at major branch points of cerebral arteries, which can lead to aneurysmal subarachnoid hemorrhage (aSAH) upon rupture. Recent studies have identified developmental endothelial locus-1 (DEL1) as closely associated with IA, though its role remains not fully understood. This study aimed to investigate serum DEL1 level differences in IA patients and explore its function in vascular endothelial cells.

METHODS

We enrolled 32 IA patients and 32 healthy controls at our hospital between February 2024 and August 2024. Clinical data were collected from electronic medical records. Peripheral blood samples were taken preoperatively to measure serum DEL1 concentrations using enzyme-linked immunosorbent assay (ELISA). Functional assays were conducted on human umbilical vein endothelial cells (HUVECs) in vitro.

RESULTS

Serum DEL1 levels were significantly lower in IA patients compared to healthy controls. Subgroup analysis showed that DEL1 levels were lower in patients with ruptured IAs and multiple IAs. Serum DEL1 level exhibits good performance as a biomarker for IA and aSHA. Additionally, in vitro experiments demonstrated that DEL1 knockdown (siDEL1) in HUVECs significantly enhanced cell proliferation, migration, and tube formation, while abnormal shear stress reduced endothelial DEL1 gene expression and disrupted endothelial barrier, suggesting a role in IA formation and progression.

CONCLUSION

Our findings suggest that decreased serum DEL1 levels may serve as a potential biomarker for the formation and progression of IAs. DEL1 could be a key target for future studies investigating the pathogenesis of IA and aSAH.

Elevated serum and cerebrospinal fluid levels of Interleukin-4 related to poor outcome of Aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a hemorrhagic cerebrovascular disease that seriously jeopardizes human life and health. Some studies have shown that although Interleukin-4 (IL-4) acts as an anti-inflammatory factor, IL-4 levels are elevated when the disease occurs. This study focuses on exploring the relationship between IL and 4 concentrations in the serum and cerebrospinal fluid (CSF) and poor outcome in patients with aSAH. This study was a prospective observational study and 210 aSAH patients who met the inclusion criteria were divided into two groups according to the mRS score at 3 months after discharge, and 210 healthy people were selected as controls. The IL-4 concentrations were quantitatively determined with enzyme-linked adsorption assay (ELISA). We can draw a conclusion that Serum and CSF IL-4 concentrations are generally elevated in patients with poor outcome(P < 0.05), and the CSF IL-4 concentration decreased gradually over the progress of time (P < 0.05). The IL-4 concentration in the CSF was positively correlated with age, platelet-lymphocyte ratio (PLR), C-reactive protein (CRP), Hunt-Hess grade, mRS score, and World Federation of Neurological Surgeons score (WFNS) (P < 0.0001). Additionally, IL-4 concentrations in the CSF were correlated with complications such as intracranial infection (P = 0.01), cerebral edema (P < 0.01), hydrocephalus (P = 0.02), and complications by DCI (P = 0.02). Elevated serum and CSF concentrations of IL-4 may associated with the outcome of aSAH and may be a candidate early biomarkers for outcome of aSAH.

Dynamic changes of systemic inflammation response index and systemic immune-inflammation index are associated with delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

OBJECTIVES

Delayed cerebral ischemia (DCI) is a factor contributing to poor outcome of aneurysmal subarachnoid hemorrhage (aSAH). Serial inflammatory response is known to affect the occurrence of DCI. The aim of this study was to evaluate associations of dynamic changes of various inflammatory markers with occurrence of DCI after aSAH.

METHODS

A total of 279 patients with interventional treatment for aSAH were enrolled, and dichotomized according to the occurrence of DCI. Various inflammatory markers, including systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), and their dynamic changes were analyzed at four different time points. Receiver operating characteristic (ROC) curve analysis with area under the curve (AUC) and univariate, multivariate Cox regression analyses with hazard ratio (HR) and 95 % confidence interval (CI) were performed to identify predictors for DCI.

RESULTS

Differences of SII and SIRI values between DCI (+) and DCI (-) group were significantly higher at 5-7 days than at other time points (P < 0.001 and P < 0.001, respectively). SII and SIRI had higher predicting values for DCI occurrence than other inflammatory markers (AUC: 0.862, 95 % CI: 0.786-0.928; P < 0.001 and AUC: 0.851, 95 % CI: 0.769-0.913; P < 0.001, respectively). SII at 5-7 days (HR: 1.74, 95 % CI: 1.38-3.22, P = 0.020) and SIRI at 5-7 days (HR: 1.62, 95 % CI: 1.28-2.84, P = 0.035) were associated with occurrence of DCI.

CONCLUSIONS

Dynamic changes of SII and SII might be predictors of DCI occurrence in patients with aSAH.

Pan-immune-inflammation value predict delayed cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage

Inflammatory reaction and immune dysregulation are known as components contributing to delayed cerebral ischemia (DCI) in patients with following aneurysmal subarachnoid hemorrhage (aSAH). The objective of this study was to investigate the role of pan-immune-inflammation value (PIV) as a novel comprehensive inflammatory marker in predicting the DCI development following aSAH. A total of 1028 participants with aSAH were enrolled. There were 296 patients with DCI and 732 patients without DCI. Various inflammatory markers were analyzed using peripheral blood sample obtained at admission. Receiver operating characteristic (ROC) analysis was performed to identify the optimal cutoff value of PIV for distinguishing DCI. Multivariate analysis was used to determine independent predictors for DCI. Mean PIV was significantly higher in the DCI (+) group than in the DCI (-) group (437.6 ± 214.7 vs 242.1 ± 154.7, P = 0.007). In ROC analysis, the optimal cutoff value of PIV was 356.7 for predicting DCI (area under the curve [AUC] 0.772, 95 % confidence interval [CI] 0.718-0.816; P < 0.001). Multivariate analysis showed that high Hunt-Hess grade (odds ratio [OR] 1.70, 95 % CI 1.38-2.22; P = 0.007), thick SAH (OR 1.82, 95 % CI 1.44-2.32; P = 0.005), and elevated PIV (≥356.7) (OR 1.42, 95 % CI 1.10-1.74; P = 0.013) were independent predictors of DCI after aSAH. PIV is a potent predictor of DCI in patients with aSAH. Elevated PIV is associated with more DCI development. Thus, PIV has predictive value for DCI development.

Blood inflammatory biomarkers predict in-hospital pneumonia after endovascular treatment of aneurysm in patients with aneurysmal subarachoid hemorrhage

The systemic inflammatory response index (SIRI) is a well-known marker of systemic inflammation reflecting the body's inflammatory/immune state. The study aimed to evaluate the relationship between the SIRI on admission and aneurysmal subarachnoid hemorrhage (aSAH)-associated pneumonia and compare with other currently used bio-markers. We reviewed 562 successive patients with aneurysmal SAH who underwent endovascular treatment between January 2019 and September 2021. ASAH-associated pneumonia was diagnosed using the modified Centers for Disease Control and Prevention criteria. The SIRI on admission was calculated as monocyte count × neutrophil count / lymphocyte count. Multiple logistic regression models were used for data analysis. A total of 158 (28.11%) patients developed aSAH-associated pneumonia. Using the Multiple logistic regression analysis, a notable dose-response association was found between the elevated SIRI (fourth quartile) and aSAH-associated pneumonia (adjusted odds ratio = 6.759; 95% confidence interval [CI], 3.280-13.930; p < 0.001 [p for trend < 0.001]). The SIRI (0.701, 95% CI: 0.653-0.749) presented a higher area under the curve (AUC) than systemic immune- inflammation index (SII) (0.669, 95% CI: 0.620-0.718) (p = 0.089); neutrophil-to-lymphocyte ratio (NLR) (0.665, 95% CI: 0.616-0.714) (p = 0.035) and platelet-lymphocyte ratio (PLR) (0.587, 95% CI: 0.534-0.641) (p < 0.001). A higher SIRI on admission was associated with aSAH-associated pneumonia, which may guide further clinical trials of prophylactic antibiotic therapy.

The potential of high-order features of routine blood test in predicting the prognosis of non-small cell lung cancer

BACKGROUND

Numerous studies have demonstrated that the high-order features (HOFs) of blood test data can be used to predict the prognosis of patients with different types of cancer. Although the majority of blood HOFs can be divided into inflammatory or nutritional markers, there are still numerous that have not been classified correctly, with the same feature being named differently. It is an urgent need to reclassify the blood HOFs and comprehensively assess their potential for cancer prognosis.

METHODS

Initially, a review of existing literature was conducted to identify the high-order features (HOFs) and classify them based on their calculation method. Subsequently, a cohort of patients diagnosed with non-small cell lung cancer (NSCLC) was established, and their clinical information prior to treatment was collected, including low-order features (LOFs) obtained from routine blood tests. The HOFs were then computed and their associations with clinical features were examined. Using the LOF and HOF data sets, a deep learning algorithm called DeepSurv was utilized to predict the prognostic risk values. The effectiveness of each data set's prediction was evaluated using the decision curve analysis (DCA). Finally, a prognostic model in the form of a nomogram was developed, and its accuracy was assessed using the calibration curve.

RESULTS

From 1210 documents, over 160 blood HOFs were obtained, arranged into 110, and divided into three distinct categories: 76 proportional features, 6 composition features, and 28 scoring features. Correlation analysis did not reveal a strong association between blood features and clinical features; however, the risk value predicted by the DeepSurv LOF- and HOF-models is significantly linked to the stage. Results from DCA showed that the HOF model was superior to the LOF model in terms of prediction, and that the risk value predicted by the blood data model could be employed as a complementary factor to enhance the prognosis of patients. A nomograph was created with a C-index value of 0.74, which is capable of providing a reasonably accurate prediction of 1-year and 3-year overall survival for patients.

CONCLUSIONS

This research initially explored the categorization and nomenclature of blood HOF, and proved its potential in lung cancer prognosis.

The clinical significance of peripheral blood cell ratios in patients with intracranial aneurysm

Background and objective

Inflammation is an important factor in the development of aneurysm, and has been identified as a key characteristic predictive of rupture of intracranial aneurysm (IA). However, the role of inflammatory peripheral blood cell ratios in patients with IA has not been well delineated.

Methods

A total of 1,209 patients, including 1,001 with unruptured IA and 208 with ruptured IA, were enrolled in this study. Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), platelet-to-neutrophil ratio (PNR), and platelet-to-white-blood-cell ratio (PWR) were compared between ruptured and unruptured IA.

Results

Compared with the ruptured IA group, the unruptured IA group had higher PNR {median, 65.96 [interquartile range (IQR) 48.95-85.05] vs. 37.78 (IQR, 23.17-54.05); p < 0.001} and PWR [median, 36.89 (IQR 29.38-44.56) vs. 22.39 (IQR, 16.72-29.29); p < 0.001]. In multivariate analysis, PNR and PWR were independently associated with ruptured IA (p = 0.001 and p < 0.001, respectively). Unruptured IA subgroup analyses according to the PHASES scores showed that a higher PHASES score was associated with significantly higher NLR and erythrocyte sedimentation rate (p < 0.001 and p = 0.025) and lower PNR and PWR (p < 0.001 and p = 0.007).

Conclusions

We demonstrated that lower PNR and PWR levels are associated with ruptured IA and a higher PHASES score. Unlike many other inflammatory markers and bioassays, peripheral blood cell ratios are inexpensive and readily available biomarkers that may be useful for risk stratification in patients with cerebral aneurysm. However, a long-term prospective study is needed to clarify this matter.

Systemic immune-inflammation index as a potential biomarker of cardiovascular diseases: A systematic review and meta-analysis

Background

Several studies have investigated the value of the systemic immune-inflammation index (SII) for predicting cardiovascular disease (CVD), but the results were inconsistent. Therefore, a meta-analysis and systematic review were conducted to assess the correlation between SII and risk of CVD.

Materials and methods

Two investigators systematically searched PubMed, Embase, Web of Science, Cochrane library, and CINAHL databases to identify all studies that examined the association between SII levels and CVD. The risk estimates of CVD for people with high SII compared to those with low SII levels and the weighted mean difference (WMD) between the CVD and control groups were pooled using fixed- or random-effects models based on the heterogeneity test. We used the Newcastle-Ottawa Scale to assess the risk of bias in eligible studies, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system was applied to rate the certainty of evidence.

Results

A total of 13 studies with 152,996 participants were included for analysis. The overall pooled results showed that higher SII was significantly associated with an increased risk of CVD (HR = 1.39, 95%CI: 1.20–1.61, P < 0.001). This increased risk could be observed in almost all CVD subtypes, including ischemic stroke (HR = 1.31, 95%CI: 1.06–1.63, P = 0.013), hemorrhagic stroke (HR = 1.22, 95%CI: 1.10–1.37, P < 0.001), myocardial infarction (HR = 1.11, 95%CI: 1.01–1.23, P = 0.027), and peripheral arterial disease (HR = 1.51, 95%CI: 1.18–1.93, P = 0.001). There were no significant but still similar trends in venous thrombosis (HR = 4.65, 95%CI: 0.66–32.71, P = 0.122), cerebral small vessel disease (HR = 1.09, 95%CI: 0.95–1.25, P = 0.233), and acute coronary syndrome (HR = 1.08, 95%CI: 0.96–1.22, P = 0.200). Furthermore, the pooled results showed that SII levels at the onset of CVD were significantly higher than that in the general population (WMD = 355.2, 95%CI: 234.8–475.6, P < 0.001), which was consistent across different CVD subtypes. The GRADE assessment suggested that the quality of current evidence from observational studies was low or very low.

Conclusion

This study indicated that SII may be a potential biomarker for CVD development and elevated SII is associated with an increased risk of CVD. However, the quality of evidence is generally low. Additional well-designed studies are necessary to determine the optimal cutoff value and to characterize the benefited population.

Inflammation and Oxidative Stress: Potential Targets for Improving Prognosis After Subarachnoid Hemorrhage

Subarachnoid hemorrhage (SAH) has a high mortality rate and causes long-term disability in many patients, often associated with cognitive impairment. However, the pathogenesis of delayed brain dysfunction after SAH is not fully understood. A growing body of evidence suggests that neuroinflammation and oxidative stress play a negative role in neurofunctional deficits. Red blood cells and hemoglobin, immune cells, proinflammatory cytokines, and peroxidases are directly or indirectly involved in the regulation of neuroinflammation and oxidative stress in the central nervous system after SAH. This review explores the role of various cellular and acellular components in secondary inflammation and oxidative stress after SAH, and aims to provide new ideas for clinical treatment to improve the prognosis of SAH.

Clinical significance of platelet to neutrophil ratio and platelet to lymphocyte ratio in patients with aneurysmal subarachnoid hemorrhage

The aim of study was aimed to investigate associations of platelet-to-neutrophil ratio (PNR) and platelet-to-lymphocyte ratio (PLR) on admission with clinical outcomes of patients with aneurysmal subarachnoid hemorrhage (aSAH). A retrospective analysis was performed on patients who were treated for aSAH. Unfavorable clinical outcome was defined as Modified Rankin Scale (mRS) score of 3-6 at 90-days. Receiver operating characteristic curve analysis was performed to detect optimal cutoff values of PNR and PLR for predicting clinical outcomes. Logistic regression was used to explore associations of PNR and PLR with clinical outcomes. A total of 544 patients with aSAH were enrolled. Of them, 152 (29.9%) had unfavorable clinical outcome. Optimal cutoff values of PNR and PLR to predict clinical outcomes at 90 days after aSAH were 25 and 130, respectively (P < 0.001 and <0.001, respectively). In multivariate logistic regression analysis, PNR <25 and PLR ≥ 130 were associated with unfavorable clinical outcome at 90 days after aSAH (odds ratio [OR]: 1.81; 95% confidence interval [CI]: 1.23-3.69; P = 0.018 and OR: 1.56; 95% CI: 1.18-2.62; P = 0.031, respectively). PNR and PLR as novel inflammatory biomarkers could predict the clinical outcome after aSAH. PNR <22 and PLR ≥ 130 were associated with unfavorable clinical outcome at 90 days after aSAH.

Identification of Circulating Gene Expression Signatures of Intracranial Aneurysm in Peripheral Blood Mononuclear Cells

Peripheral blood mononuclear cells (PBMCs) play an important role in the inflammation that accompanies intracranial aneurysm (IA) pathophysiology. We hypothesized that PBMCs have different transcriptional profiles in patients harboring IAs as compared to IA-free controls, which could be the basis for potential blood-based biomarkers for the disease. To test this, we isolated PBMC RNA from whole blood of 52 subjects (24 with IA, 28 without) and performed next-generation RNA sequencing to obtain their transcriptomes. In a randomly assigned discovery cohort of n = 39 patients, we performed differential expression analysis to define an IA-associated signature of 54 genes (q < 0.05 and an absolute fold-change ≥ 1.3). In the withheld validation dataset, these genes could delineate patients with IAs from controls, as the majority of them still had the same direction of expression difference. Bioinformatics analyses by gene ontology enrichment analysis and Ingenuity Pathway Analysis (IPA) demonstrated enrichment of structural regulation processes, intracellular signaling function, regulation of ion transport, and cell adhesion. IPA analysis showed that these processes were likely coordinated through NF-kB, cytokine signaling, growth factors, and TNF activity. Correlation analysis with aneurysm size and risk assessment metrics showed that 4/54 genes were associated with rupture risk. These findings highlight the potential to develop predictive biomarkers from PBMCs to identify patients harboring IAs.

Systemic Inflammation Response Index and Systemic Immune-inflammation Index for Predicting the Prognosis of Patients with Aneurysmal Subarachnoid Hemorrhage

OBJECTIVES

Inflammatory response plays a pivotal role in the progress of aneurysmal subarachnoid hemorrhage (aSAH). As novel inflammatory markers, systemic inflammation response index (SIRI) and systemic immune-inflammation (SII) index could reflect clinical outcomes of patients with various diseases. The aim of this study was to ascertain whether initial SIRI and SII index were associated with prognosis of aSAH patients.

METHODS

A total of 680 patients with aSAH were enrolled. Their prognosis was evaluated with modified Rankin Scale (mRS) at 3 months, and unfavorable clinical outcome was defined as mRS score of 3-6. Receiver operating characteristic (ROC) curve analysis was performed to identify cutoff values of SIRI and SII index for predicting clinical outcomes. Univariate and multivariate regression analyses were performed to explore relationships of SIRI and SII index with prognosis of patients.

RESULTS

Optimal cutoff values of SIRI and SII index to discriminate between favorable and unfavorable clinical outcomes were 3.2 × 10⁹/L and 960 × 10⁹/L, respectively (P < 0.001 and 0.004, respectively). In multivariate analysis, SIRI value ≥ 3.2 × 10⁹/L (odds ratio [OR]: 1.82, 95% CI: 1.46-3.24; P = 0.021) and SII index value ≥ 960 × 10⁹/L (OR: 1.68, 95% CI: 1.24-2.74; P = 0.040) were independent predicting factors for poor prognosis after aSAH.

CONCLUSIONS

SIRI and SII index values are associated with clinical outcomes of patients with aSAH. Elevated SIRI and SII index could be independent predicting factors for a poor prognosis after aSAH.

The Pathogenesis of Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage

Hydrocephalus is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) and reportedly contributes to poor neurological outcomes. In this review, we summarize the molecular and cellular mechanisms involved in the pathogenesis of hydrocephalus following aSAH and summarize its treatment strategies. Various mechanisms have been implicated for the development of chronic hydrocephalus following aSAH, including alterations in cerebral spinal fluid (CSF) dynamics, obstruction of the arachnoid granulations by blood products, and adhesions within the ventricular system. Regarding molecular mechanisms that cause chronic hydrocephalus following aSAH, we carried out an extensive review of animal studies and clinical trials about the transforming growth factor-β/SMAD signaling pathway, upregulation of tenascin-C, inflammation-dependent hypersecretion of CSF, systemic inflammatory response syndrome, and immune dysregulation. To identify the ideal treatment strategy, we discuss the predictive factors of shunt-dependent hydrocephalus between surgical clipping and endovascular coiling groups. The efficacy and safety of other surgical interventions including the endoscopic removal of an intraventricular hemorrhage, placement of an external ventricular drain, the use of intraventricular or cisternal fibrinolysis, and an endoscopic third ventriculostomy on shunt dependency following aSAH were also assessed. However, the optimal treatment is still controversial, and it necessitates further investigations. A better understanding of the pathogenesis of acute and chronic hydrocephalus following aSAH would facilitate the development of treatments and improve the outcome.