A Computational Model of Blood D-Dimer, Cystatin C, and CRP Levels Predicts the Risk of Intracranial Aneurysms and their Rupture.

Objective: The aim of this study is to construct a computational model of blood D-dimer, cystatin C, and CRP levels and to predict the risk of intracranial aneurysms and their rupture. Methods: A total of 69 intracranial aneurysms patients were selected as the case group, including 28 cases in the ruptured group and 41 cases in the unruptured group. Another 64 non-intracranial aneurysm patients were selected as the control group. The detection results of serum D-dimer, cystatin C, and CRP were collected. The logistic regression computational model was used to analyze the occurrence and risk factors of intracranial aneurysms. The receiver operating curves (ROC) of serum D-dimer, cystatin C, and C reactive protein (CRP) levels for predicting intracranial aneurysms and their rupture were drawn, and the area under the curve (AUC), sensitivity, and specificity were calculated. Results: The serum levels of D-dimer, cystatin C, and CRP in patients with intracranial aneurysms were significantly higher than those in the control group and the differences were statistically significant (P < 0.05). The serum levels of D-dimer, cystatin C, and CRP in patients with ruptured intracranial aneurysms were higher than those in patients with unruptured intracranial aneurysms, and the differences were also statistically significant (P < 0.05). The combined detection of serum D-dimer, cystatin C, and CRP levels has a higher AUC (0.9014) for predicting intracranial aneurysms and higher AUC (0.9412) for predicting ruptured intracranial aneurysms than D-dimer (0.7118 and 0.8750, respectively), cystatin C (0.6489 and 0.6180, respectively), and CRP (0.7764 and 0.6551, respectively) independent detection; the combined detection had a sensitivity of 93.75% and 87.80 for predicting the occurrence and rupture of intracranial aneurysms, and the specificity was 68.12% and 92.86%, respectively. Conclusion: The combined detection of serum D-dimer, cystatin C, and CRP levels is a very valuable indicator for predicting the occurrence and rupture of intracranial aneurysms, and combined detection can provide scientific evidence-based guidance for clinical prediction of the occurrence and rupture of intracranial aneurysms.

Identifying critical genes associated with aneurysmal subarachnoid hemorrhage by weighted gene co-expression network analysis.

Aneurysmal subarachnoid hemorrhage (aSAH) is a life-threatening medical condition with a high mortality and disability rate. aSAH has an unclear pathogenesis, and limited treatment options are available. Here, we aimed to identify critical genes involved in aSAH pathogenesis using peripheral blood gene expression data of 43 patients with aSAH due to ruptured intracranial aneurysms and 18 controls with headache, downloaded from Gene Expression Omnibus. These data were used to construct a co-expression network using weighted gene co-expression network analysis (WGCNA). The biological functions of the hub genes were explored, and critical genes were selected by combining with differentially expressed genes analysis. Fourteen modules were identified by WGCNA. Among those modules, red, blue, brown and cyan modules were closely associated with aSAH. Moreover, 364 hub genes in the significant modules were found to play important roles in aSAH. Biological function analysis suggested that protein biosynthesis-related processes and inflammatory responses-related processes were involved in the pathology of aSAH pathology. Combined with differentially expressed genes analysis and validation in 35 clinical samples, seven gene (CD27, ANXA3, ACSL1, PGLYRP1, ALPL, ARG1, and TPST1) were identified as potential biomarkers for aSAH, and three genes (ANXA3, ALPL, and ARG1) were changed with disease development, that may provide new insights into potential molecular mechanisms for aSAH.

The relationship between the level of vitamin D and ruptured intracranial aneurysms.

The purpose of our research is to explore whether vitamin D levels were associated with the rupture of intracranial aneurysms. In this retrospective study, 105 patients diagnosed with ruptured intracranial aneurysms (RIAs) and 185 patients diagnosed with unruptured intracranial aneurysms (UIAs) at The First Affiliated Hospital of Zhengzhou University were recruited from September 2019 to September 2020. Patients' demographic and clinical information, including vitamin D levels, were recorded and compared. Univariate analysis showed that patients with UIAs had higher vitamin D levels than RIAs (p = 0.019). In addition, there were significant differences in aneurysm location (p < 0.001), aspirin use (p = 0.001), and comorbid diabetes mellitus (p = 0.037) between patients with UIAs and RIAs. Binary logistic regression analysis showed that the level of vitamin D was independently associated with RIAs [odds ratio (OR) 0.960; 95% confidence intervals (CI), 0.926-0.996, p = 0.028].

Clinical application values of neutrophil-to-lymphocyte ratio in intracranial aneurysms.

Inflammation plays an important role in the pathogenesis and growth of intracranial aneurysms (IAs). We investigated the clinical value of the neutrophil-to-lymphocyte ratio (NLR) as a marker of systemic subclinical inflammation in patients with IAs. Consecutive patients with IAs who underwent endovascular treatment (EVT) were enrolled in the study. The evaluation indicators were aneurysm size and rupture, a poor outcome at 3 to 6 months, and delayed cerebral ischemia (DCI) during hospitalization. In total, 532 patients with IAs underwent EVT (mean age, 54.0 years; 62.4% female). Among patients with ruptured IAs, those with a higher NLR had an increased risk of a poor outcome at 3 to 6 months and DCI during hospitalization than those with a lower NLR. A higher NLR was significantly more strongly associated with the size of unruptured aneurysms and aneurysm rupture than a lower NLR. The NLR and C-reactive protein concentration showed similar predictive ability for aneurysm size and treatment prognosis. The NLR was lower at discharge than admission for patients with ruptured IAs and DCI. An elevated NLR was significantly associated with the size of unruptured IAs, an increased risk of a poor outcome, and DCI in patients with ruptured IAs.

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

BACKGROUND: The rupture of an intracranial aneurysm (IA) causes a systemic response that involves an immune/inflammatory reaction. We sought to characterize the systemic response to IA rupture. METHODS: We included 19 patients in the acute phase of IA rupture and 20 control subjects. Flow cytometry was used to analyze alterations in the level of mononuclear leukocytes. Cell-related parameters, including the neutrophil-to-lymphocyte ratio (NL-R), lymphocyte-to-monocyte ratio (LM-R), platelet-to-lymphocyte ratio (PL-R), and systemic immune-inflammation index (SII), were calculated, and the relationship between the analyzed hematological parameters and clinical status was investigated. RESULTS: Patients with ruptured IAs presented with significantly higher white blood cells (WBC) and neutrophil counts but lower lymphocyte counts than control subjects. NL-R and SII values were higher and the LM-R was lower in the acute phase after IA rupture. Analyzing the severity of clinical status and the outcome of patients with subarachnoid hemorrhage, we found that patients with poor clinical status, as measured by the Glasgow Coma Scale (GCS) and the Hunt and Hess scale, had significantly lower lymphocyte counts and higher NL-R, PL-R and SII values than those with good clinical status. Additionally, patients with lower GCS scores presented a lower proportion of CD3+CD4-CD8- cells. Worse outcomes assessed at discharge were associated with lower lymphocyte counts but higher PL-R values. CONCLUSIONS: The current study pointed to the significance of systemic immune and inflammatory responses after IA rupture and the potential clinical utility of hematological parameters, which can be easily calculated. In particular, the role of DN T cells and the significance of the SII as a marker related to clinical status should be further investigated.

Elevation of inflammatory S100A8/S100A9 complexes in intracranial aneurysms.

BACKGROUND: Inflammation-related factors might give further insight into the pathophysiology of vessel wall inflammation and intracranial aneurysm (IA) rupture. One of these factors is the protein complex S100A8/A9, which is released by neutrophils, monocytes, and activated macrophages and is known for its role in cardiovascular disease. OBJECTIVE: To determine if venous S100A8/A9 levels in patients with a ruptured IA (rIA) or unruptured IA (uIA) are elevated compared with a control group. Second, to assess differences between venous and intra-aneurysmal S100A8/A9 levels of rIA and uIA patients. METHODS: A prospective case study was performed between June 2016 and May 2017 in patients harboring a ruptured or unruptured saccular IA. Primary outcome measures were individual S100A8/A9 serum concentrations as measured in venous and intra-aneurysmal blood samples during endovascular treatment. Venous serum S100A8/A9 concentrations from a healthy control group served as a reference. RESULTS: We included 16 patients with either a rIA or uIA and 47 healthy controls. Venous S100A8/A9 concentrations were higher in aneurysm patients (rIA and uIA) than those of healthy controls (P≤0.001). S100A8/A9 concentrations were higher in intra-aneurysmal samples than in venous samples of rIA patients (P=0.011). This difference was not found in uIA patients (P=0.054). Intra-aneurysmal S100A8/A9 levels were higher in rIAs than in uIAs (P=0.04). CONCLUSIONS: Venous S100A8/A9 levels are elevated in patients with both rIAs and uIAs compared with healthy controls and likely represents aneurysm wall inflammation. S100A8/A9 causes macrophage-induced inflammation and degeneration of the vessel wall which might explain higher intra-aneurysmal S100A8/A9 levels found in rIAs than in uIAs.

Prognostic models for neurological functional outcomes in aneurysmal subarachnoid hemorrhage patients with intracranial hematoma.

OBJECTIVES: Current guidelines paid little attention to a unique severe disease about intracranial hematoma owing to aneurysm rupture. We attempted to explore the predictive factors for prognosis in these poor patient population. PATIENTS AND METHODS: One hundred twenty-one aneurysmal subarachnoid hemorrhage combined with intracerebral hematoma patients discharged between 2013 and 2016 were reviewed in this retrospective study. Unfavorable outcome was defined as a modified Rankin Scale (mRS) score of 3, 4, 5, or 6 at 6 months. Multivariable logistic regression was performed to evaluate the association of unfavorable outcome with preoperative and postoperative clinical characteristics. RESULTS: Of 121 patients with intact follow-up data, 34 (28.10 %) had an unfavorable prognosis. The preoperative prognostic model included patients' age, respiratory rate, Hunt-Hess scale, red cell distribution width, and serum sodium at admission. The postoperative prognostic model included patients' age, respiratory rate, red cell distribution width, serum sodium, postoperative delayed cerebral ischemia, and pulmonary infection. Both preoperative and postoperative prognostic models had excellent discrimination with Area Under The Curve (AUC) of 0.864 (P < .001) and 0.898 (P < .001), respectively. CONCLUSION: In clinical practice, we should pay more attention to those old patients with worse admission Hunt-Hess score, presenting deep-slow respiratory and lower serum sodium. Reduction of postoperative delayed cerebral ischemia and pulmonary infection might improve outcomes after aneurysmal SAH with intracerebral hematoma.

Serum myelin basic protein as a marker of brain injury in aneurysmal subarachnoid haemorrhage.

BACKGROUND: Myelin basic protein (MBP) is the second most abundant protein in central nervous system myelin. Since the 1980s, it has been regarded as a marker of brain tissue injury in both trauma and disease. There have been no recent reports regarding MBP in aneurysmal subarachnoid haemorrhage (SAH). METHODS: One hundred four SAH patients with ruptured aneurysms underwent endovascular treatment within 24 h of rupture, and 156 blood samples were collected: 104 on days 0-3, 32 on days 4-6 and 20 on days 9-12 post-SAH. MBP levels were assayed using ELISA and compared with the clinical status on admission, laboratory results, imaging findings and treatment outcome at 3 months. RESULTS: MBP levels on days 0-3 post-SAH were significantly higher among poor outcome patients (p < 0.001), non-survivors (p = 0.005), patients who underwent intracranial intervention (p < 0.001) and patients with intracerebral haemorrhage (ICH; p < 0.001). On days 4-6 post-SAH, significantly higher levels were found following intracranial intervention (p = 0.009) and ICH (p = 0.039). There was clinically relevant correlation between MBP levels on days 0-3 post-SAH and 3-month Glasgow Outcome Scale (cc = - 0.42) and also ICH volume (cc = 0.48). All patients who made a full recovery had MBP levels below detection limit on days 0-3 post-SAH. Following endovascular aneurysm occlusion, there was no increase in MBP in 86 of the 104 patients investigated (83%). CONCLUSIONS: The concentration of MBP in peripheral blood after intracranial aneurysm rupture reflects the severity of the brain tissue injury (due to surgery or ICH) and correlates with the treatment outcome. Endovascular aneurysm occlusion was not followed by a rise in MBP in most cases, suggesting the safety of this technique.

Analysis of Peripheral Blood Cells' Transcriptome in Patients With Subarachnoid Hemorrhage From Ruptured Aneurysm Reveals Potential Biomarkers.

BACKGROUND: Subarachnoid hemorrhage (SAH) is an uncommon disease. Considering ruptured intracranial aneurysms as the main cause of this disease and only a minority of the intracranial aneurysms will rupture sooner or later, to understand the underlying pathology or a specific gene expression profile of an impending ruptured intracranial aneurysm is of great importance. METHODS: The transcriptome in peripheral blood cells of patients with SAH from ruptured aneurysm was compared with that of control patients suffering from headaches. The microarray dataset GSE36791 comprised 43 patients with SAH from ruptured aneurysms and 18 control patients. Differential expression analysis was performed with the R language packages to identify differentially expressed genes (DEGs). Gene Ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway database analysis were performed to identify significantly altered biological functions and pathways, respectively. The protein-protein interaction networks were constructed with information from the STRING database. RESULTS: A total of 528 DEGs were identified, of which 311 were upregulated and 217 downregulated. Clustering analysis confirmed that these genes can distinguish ruptured aneurysm SAH patients from the control patients. The DEGs were mainly enriched for immune/inflammation response and related pathways. Among the DEGs, 8 genes (ARG1, MAPK14, RPS2, SPI1, FYN, CEBPB, FLOT1, and CD4) were identified as the key regulators in the Protein-Protein Interaction network. MAPK14, CEBPB, FLOT1, and CD4 might be potential biomarkers of SAH. CONCLUSION: This study identified a range of DEGs SAH patients with ruptured aneurysms, which may enhance our current knowledge on this disease and may provide potential biomarkers of this disease.

Lower Hemoglobin Levels Are Associated with Acute Seizures in Patients with Ruptured Cerebral Aneurysms.

OBJECTIVE: We tested the hypothesis that low hemoglobin levels are associated with acute seizures after aneurysmal subarachnoid hemorrhage (aSAH). METHODS: Patients with ruptured intracranial aneurysms were enrolled in the observational cohort study that prospectively collected age, sex, symptom onset, history of diabetes and hypertension, history of coronary artery disease, temperature, Hunt-Hess grade, Fisher grade, aneurysm location, hemoglobin, hematocrit, serum potassium, sodium, calcium, phosphorus, iron, and modified Rankin Scale. Acute seizures were determined as seizures within 1 week after aSAH. RESULTS: We included 554 patients with requisite data for analysis in the prospective study. Incidence of acute seizures following aSAH was 3.61%. In the univariate analysis, significant differences were detected in admission Hunt-Hess grade, Fisher grade, hemoglobin, and serum iron between epilepsy and nonepilepsy groups. Furthermore, acute seizures were associated with higher modified Rankin Scale score and poor outcome (P = 0.004). Serum hemoglobin levels were 114.30 ± 20.08 g/L in the epilepsy group, which were lower than those in the nonepilepsy group (128.64 ± 17.94 mmol/L, P = 0.001). Serum iron levels were 8.89 ± 5.03 g/L in the epilepsy group, which were also lower than those in the nonepilepsy group (13.71 ± 6.70 mmol/L, P = 0.002). The hemoglobin level was positively correlated with serum iron on admission (ρ = 0.321, P = 0.000). In the multivariate logistic regression model, lower hemoglobin was considered as an independent risk factor of acute seizures (odds ratio 4.286, 95% confidence interval 1.492-12.315, P = 0.007). The optimal cutoff value for hemoglobin level as a predictor for acute epilepsy after aSAH was determined as 119 g/L in the receiver operating characteristic curve (sensitivity was 75.00%, and specificity was 69.48%). CONCLUSIONS: These data support the hypothesis that hemoglobin was inversely associated with acute seizures following aSAH.

Decreased Total Iron Binding Capacity May Correlate with Ruptured Intracranial Aneurysms.

Iron and its derivatives play a significant role in various physiological and biochemical pathways, and are influenced by a wide variety of inflammatory, infectious, and immunological disorders. We hypothesized that iron and its related factors play a role in intracranial aneurysm pathophysiology and investigated if serum iron values are associated with ruptured intracranial aneurysms. 4,701 patients with 6,411 intracranial aneurysms, including 1201 prospective patients, who were diagnosed at the Massachusetts General Hospital and Brigham and Women's Hospital between 1990 and 2016 were evaluated. A total of 366 patients with available serum iron, ferritin and total iron binding capacity (TIBC) values were ultimately included in the analysis. 89% of included patients had anemia. Patients were categorized into ruptured and non-ruptured groups. Univariable and multivariable logistic regression analyses were performed to determine the association between ruptured aneurysms and iron, ferritin, and TIBC. TIBC values (10-3 g/L) within 1 year of diagnosis (OR 0.41, 95% CI 0.28-0.59) and between 1 and 3 years from diagnosis (OR 0.52, 95% CI 0.29-0.93) were significantly and inversely associated with intracranial aneurysm rupture. In contrast, serum iron and ferritin were not significant. In this case-control study, low TIBC was significantly associated with ruptured aneurysms, both in the short- and long term. However, this association may not apply to the general population as there may be a selection bias as iron studies were done in a subset of patients only.

Biomarkers from circulating neutrophil transcriptomes have potential to detect unruptured intracranial aneurysms.

BACKGROUND: Intracranial aneurysms (IAs) are dangerous because of their potential to rupture and cause deadly subarachnoid hemorrhages. Previously, we found significant RNA expression differences in circulating neutrophils between patients with unruptured IAs and aneurysm-free controls. Searching for circulating biomarkers for unruptured IAs, we tested the feasibility of developing classification algorithms that use neutrophil RNA expression levels from blood samples to predict the presence of an IA. METHODS: Neutrophil RNA extracted from blood samples from 40 patients (20 with angiography-confirmed unruptured IA, 20 angiography-confirmed IA-free controls) was subjected to next-generation RNA sequencing to obtain neutrophil transcriptomes. In a randomly-selected training cohort of 30 of the 40 samples (15 with IA, 15 controls), we performed differential expression analysis. Significantly differentially expressed transcripts (false discovery rate < 0.05, fold change ≥ 1.5) were used to construct prediction models for IA using four well-known supervised machine-learning approaches (diagonal linear discriminant analysis, cosine nearest neighbors, nearest shrunken centroids, and support vector machines). These models were tested in a testing cohort of the remaining 10 neutrophil samples from the 40 patients (5 with IA, 5 controls), and model performance was assessed by receiver-operating-characteristic (ROC) curves. Real-time quantitative polymerase chain reaction (PCR) was used to corroborate expression differences of a subset of model transcripts in neutrophil samples from a new, separate validation cohort of 10 patients (5 with IA, 5 controls). RESULTS: The training cohort yielded 26 highly significantly differentially expressed neutrophil transcripts. Models using these transcripts identified IA patients in the testing cohort with accuracy ranging from 0.60 to 0.90. The best performing model was the diagonal linear discriminant analysis classifier (area under the ROC curve = 0.80 and accuracy = 0.90). Six of seven differentially expressed genes we tested were confirmed by quantitative PCR using isolated neutrophils from the separate validation cohort. CONCLUSIONS: Our findings demonstrate the potential of machine-learning methods to classify IA cases and create predictive models for unruptured IAs using circulating neutrophil transcriptome data. Future studies are needed to replicate these findings in larger cohorts.

Plasma Soluble Human Elastin Fragments as an Intra-Aneurysmal Localized Biomarker for Ruptured Intracranial Aneurysm.

Background Fragmentation of the tunica media is a hallmark of intracranial aneurysm formation, often leading to aneurysmal progression and subsequent rupture. The objective of this study is to determine the plasma level of elastin fragments in the lumen of ruptured versus unruptured human intracranial aneurysms. Methods and Results One hundred consecutive patients with/without ruptured saccular intracranial aneurysms undergoing endovascular coiling or stent-assisted coiling were recruited. Blood samples were collected from the lumen of intracranial aneurysm using a microcatheter. The tip of the microcatheter was placed inside the aneurysm's sac in close proximity to the inner wall of the dome. Plasma levels of elastin fragments were measured using an ELISA -based method. Mean plasma level of soluble human elastin fragments was significantly greater in ruptured aneurysms when compared with nonruptured aneurysms (102.0±15.5 versus 39.3±9.6 ng/mL; P<0.001). Mean plasma level of soluble human elastin fragments did not have significant correlation with age, sex, size, or aneurysm location. Conclusions The present study revealed that a significantly higher concentration of soluble human elastin fragments in the lumen of ruptured intracranial aneurysms when compared with nonruptured ones.

Elevated International Normalized Ratio Is Associated With Ruptured Aneurysms.

Background and Purpose- The effects of anticoagulation therapy and elevated international normalized ratio (INR) values on the risk of aneurysmal subarachnoid hemorrhage are unknown. We aimed to investigate the association between anticoagulation therapy, elevated INR values, and rupture of intracranial aneurysms. Methods- We conducted a case-control study of 4696 patients with 6403 intracranial aneurysms, including 1198 prospective patients, diagnosed at the Massachusetts General Hospital and the Brigham and Women's Hospital between 1990 and 2016 who were on no anticoagulant therapy or on warfarin for anticoagulation. Patients were divided into ruptured and nonruptured groups. Univariable and multivariable logistic regression analyses were performed to evaluate the association of anticoagulation therapy, INR values, and presentation with a ruptured intracranial aneurysm, taking into account the interaction between anticoagulant use and INR. Inverse probability weighting using propensity scores was used to minimize differences in baseline demographics characteristics. The marginal effects of anticoagulant use on rupture risk stratified by INR values were calculated. Results- In unweighted and weighted multivariable analyses, elevated INR values were significantly associated with rupture status among patients who were not anticoagulated (unweighted odds ratio, 22.78; 95% CI, 10.85-47.81 and weighted odds ratio, 28.16; 95% CI, 12.44-63.77). In anticoagulated patients, warfarin use interacts significantly with INR when INR ≥1.2 by decreasing the effects of INR on rupture risk. Conclusions- INR elevation is associated with intracranial aneurysm rupture, but the effects may be moderated by warfarin. INR values should, therefore, be taken into consideration when counseling patients with intracranial aneurysms.

High-Density Lipoprotein Is Associated with Progression of Intracranial Aneurysms.

BACKGROUND: We tested the hypothesis that high-density lipoprotein (HDL) is associated with intracranial aneurysm growth and rupture. METHODS: We used an observational cohort study design. Age, sex, admission systolic blood pressure (SBP), diabetes, hypertension, coronary artery disease, aneurysmal rupture, apolipoprotein (APO)-A1, APO-B, HDL, low-density lipoprotein, triglycerides, cholesterol, and aneurysm location and size were recorded. Aneurysms <8 mm were categorized as small. RESULTS: The data from 581 patients with intracranial aneurysms were analyzed. The predictive factors for small size of aneurysms were female sex (odds ratio [OR], 0.630; 95% confidence interval [CI], 0.428-0.927; P = 0.019) and higher HDL (OR, 0.327; 95% CI, 0.159-0.672; P = 0.0002). In the subgroup of male patients, lower HDL was the only risk factor for large size (P = 0.015). The predictors of aneurysmal rupture were small size (OR, 0.875; 95% CI, 0.842-0.910; P = 0.000), higher HDL (OR, 3.716; 95% CI, 1.623-8.509; P = 0.002), no coronary artery disease (OR, 4.736; 95% CI, 1.528-14.681; P = 0.007), lower APO-A1 (OR, 0.202; 95% CI, 0.064-0.641; P = 0.007), and higher admission SBP (OR, 1.024; 95% CI, 1.015-1.032; P = 0.000). An HDL/aneurysm size ratio >0.31 was associated with a 46.2-fold increased likelihood of aneurysmal rupture (OR, 46.214; 95% CI, 13.386-159.548; P = 0.002). CONCLUSIONS: The HDL level was inversely associated with intracranial aneurysm growth, especially in men. Higher HDL levels and small aneurysm size contributed to a greater risk of aneurysmal rupture. An HDL/size ratio >0.31 was a valuable predictor of intracranial rupture.

Hemodynamic Stress, Inflammation, and Intracranial Aneurysm Development and Rupture: A Systematic Review.

BACKGROUND: There seems to be a pathogenetic link between hemodynamics and inflammatory arterial wall alteration leading to the development and rupture of intracranial aneurysms (IAs). Noninvasive assessment of the inflammatory status of the aneurysm wall may guide the management of unruptured IAs by identifying reliable markers for increased rupture risk. METHODS: We conducted a qualitative systematic review following the ENTREQ (Enhancing Transparency in Reporting the Synthesis of Qualitative Research) framework. A search was made in MEDLINE/PubMed, Embase, and CINAHL from database inception to October 2017 using the terms "intracranial aneurysm" and "cerebral aneurysm" linked with the following key words: inflammation, hemodynamic(s), remodeling, macrophages, neutrophils, lymphocytes, complement system, vascular smooth muscle cells, mast cells, cytokines, and inflammatory biomarkers. RESULTS: One hundred and twenty-three articles were included in the review. CONCLUSIONS: In this systematic review, we explore the relationship between hemodynamic stress, inflammation, vascular remodeling, and the formation and rupture of IAs to develop novel strategies to predict the individual risk of aneurysmal rupture.

Low Serum Calcium and Magnesium Levels and Rupture of Intracranial Aneurysms.

BACKGROUND AND PURPOSE: Both low serum calcium and magnesium levels have been associated with the extent of bleeding in patients with intracerebral hemorrhage, suggesting hypocalcemia- and hypomagnesemia-induced coagulopathy as a possible underlying mechanism. We hypothesized that serum albumin-corrected total calcium and magnesium levels are associated with ruptured intracranial aneurysms. METHODS: The medical records of 4701 patients, including 1201 prospective patients, diagnosed at the Brigham and Women's Hospital and Massachusetts General Hospital between 1990 and 2016 were reviewed and analyzed. One thousand two hundred seventy-five patients had available serum calcium, magnesium, and albumin values within 1 day of diagnosis. Individuals were divided into cases with ruptured aneurysms and controls with unruptured aneurysms. Univariable and multivariable logistic regression analyses were performed to determine the association between serum albumin-corrected total calcium and magnesium levels and ruptured aneurysms. RESULTS: In multivariable analysis, both albumin-corrected calcium (odds ratio, 0.33; 95% confidence interval, 0.27-0.40) and magnesium (odds ratio, 0.40; 95% confidence interval, 0.28-0.55) were significantly and inversely associated with ruptured intracranial aneurysms. CONCLUSIONS: In this large case-control study, hypocalcemia and hypomagnesemia at diagnosis were significantly associated with ruptured aneurysms. Impaired hemostasis caused by hypocalcemia and hypomagnesemia may explain this association.

Lipid-Lowering Agents and High HDL (High-Density Lipoprotein) Are Inversely Associated With Intracranial Aneurysm Rupture.

BACKGROUND AND PURPOSE: Growing evidence from experimental animal models and clinical studies suggests the protective effect of statin use against rupture of intracranial aneurysms; however, results from large studies detailing the relationship between intracranial aneurysm rupture and total cholesterol, HDL (high-density lipoprotein), LDL (low-density lipoprotein), and lipid-lowering agent use are lacking. METHODS: The medical records of 4701 patients with 6411 intracranial aneurysms diagnosed at the Massachusetts General Hospital and the Brigham and Women's Hospital between 1990 and 2016 were reviewed and analyzed. Patients were separated into ruptured and nonruptured groups. Univariable and multivariable logistic regression analyses were performed to determine the effects of lipids (total cholesterol, LDL, and HDL) and lipid-lowering medications on intracranial aneurysm rupture risk. Propensity score weighting was used to account for differences in baseline characteristics of the cohorts. RESULTS: Lipid-lowering agent use was significantly inversely associated with rupture status (odds ratio, 0.58; 95% confidence interval, 0.47-0.71). In a subgroup analysis of complete cases that includes both lipid-lowering agent use and lipid values, higher HDL levels (odds ratio, 0.95; 95% confidence interval, 0.93-0.98) and lipid-lowering agent use (odds ratio, 0.41; 95% confidence interval, 0.23-0.73) were both significantly and inversely associated with rupture status, whereas total cholesterol and LDL levels were not significant. A monotonic exposure-response curve between HDL levels and risk of aneurysmal rupture was obtained. CONCLUSIONS: Higher HDL values and the use of lipid-lowering agents are significantly inversely associated with ruptured intracranial aneurysms.

Levels of MMP-9 in patients with intracranial aneurysm: Relation with risk factors, size and clinical presentation.

BACKGROUND: Intracranial aneurysms are arterial anomalies affecting 2% to 3% of the general population in the world and these ruptures are associated with a high mortality. Some risk factors, such as age, gender, smoking, alcohol, hypertension and familial history are associated with the number of aneurysms and their size. In addition, inflammatory processes within the blood vessels of the brain can activate matrix metalloproteinase-9 (MMP-9), which degrades various components of the extracellular matrix, such as elastin. Thereby, this work has aimed at evaluating the relationship between plasma MMP-9 levels and the risk factors that are associated with intracranial aneurysm, as well as investigating the aneurysm statuses (ruptured and unruptured) and comparing them with the control volunteers. METHODS: Between August 2014 to June 2016, blood samples were collected from 282 patients (204 ruptured and 78 unruptured saccular intracranial aneurysms) and 286 control volunteers. The MMP-9 plasma levels were measured by ELISA. Statistical analyzes were performed with SPSS software when using parametric or nonparametric tests, after the normality tests. RESULTS: Higher levels of MMP-9 were found in the aneurysm groups as a whole and when they were stratified by rupture status, then compared with the control group (p < 0.0001). When stratifying them by diameter, those smaller than 7 mm presented high levels of MMP-9 (p < 0.0001), especially in the ruptured ones. As for risk factors, hypertension and smoking were the most important. However, hypertension was mostly associated with the ruptured aneurysms (p < 0.0001). CONCLUSIONS: High levels of MMP-9 were found in smaller ruptured and unruptured intracranial aneurysms (<7 mm) with strongest statistical associations than other sizes, especially when associated with smoking and hypertension.