Decreasing incidence of subarachnoid hemorrhage

Using eQTL Mendelian randomization and transcriptomic analysis to identify the relationship between ion channel genes and intracranial aneurysmal subarachnoid hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a complex condition associated with high disability and mortality rates, leading to poor clinical outcomes. Previous observational studies have suggested a link between ion channel genes and aSAH, but the causal relationship remains uncertain. This study utilized Mendelian randomization (MR) to explore the causal association between ion channel genes and aSAH, employing 5 MR methods: inverse variance weighted (IVW), MR-Egger, maximum likelihood, weighted median, and weighted mode. If results from these methods are inconclusive, IVW will be prioritized as the primary outcome. Additionally, MR-Egger, MR-PRESSO, and Cochrane Q tests were conducted to assess heterogeneity and pleiotropy. The stability of MR findings was evaluated using the leave-one-out approach; Bonferroni correction tested the strength of the causal relationship between exposure and outcome. The MR analysis revealed that CACNA2D3 was positively correlated with aSAH (OR 1.245; 95% confidence intervals [CI] 1.008-1.537; P = .042), while ANO6 showed a negative correlation (OR 0.728; 95% CI 0.533-0.993; P = .045). Our findings indicate that increased expression of CACNA2D3 promotes aSAH whereas elevated levels of ANO6 inhibit it. Transcriptome data from intracranial aneurysm samples confirmed significant differential expression of CACNA2D3 and ANO6 between ruptured and unruptured groups. CACNA2D3 being higher in ruptured cases while ANO6 was more expressed in unruptured ones. Furthermore, GeneMANIA analysis along with functional enrichment provided insights into risk factors for aSAH. Through MR analysis, we established a causal link between ion channel genes and aSAH, which helps to better understand the pathogenesis of aSAH and provide new therapeutic targets.

Effects of Aneurysmal Subarachnoid Hemorrhage in Patients Without In-Hospital Infection on FABP-I, LBP, and sCD-14

Aneurysmal subarachnoid hemorrhage (aSAH) is a serious condition complicated by delayed cerebral ischemia (DCI), where inflammation plays a key role. Although altered gut permeability is noted in other conditions, its significance in aSAH remains unclear. Fatty acid-binding protein (FABP-I), lipopolysaccharide-binding protein (LBP), and soluble CD-14 (sCD-14) are established markers of barrier dysfunction. This study investigates gut permeability marker changes in early and late aSAH phases. The study included 177 aSAH patients and 100 controls. Serum samples were collected on days 1 (D1) and 9 (D9) after ictus. FABP-I, LBP, and sCD-14 levels were measured via ELISA, and clinical data were recorded. Outcomes were assessed using the 90-day modified Rankin scale (mRS 0-3 = favorable outcome). Serum FABP-I was significantly lower in aSAH patients (p < 0.05), while LBP and sCD-14 were higher (p < 0.001) compared to controls. FABP-I did not differ between outcome groups, but LBP and sCD-14 were significantly elevated in unfavorable outcomes (p < 0.001). These markers differed in patients without in-hospital infection, with higher levels noted in DCI patients during the later phase (p < 0.05). In aSAH patients without infection, differences in LBP and sCD-14 levels between outcome groups suggest potential endotoxin release from microbial systems, contributing to neuroinflammation and influencing outcomes.

The HSACat Project: A Prospective Multicenter Observational Study of Spontaneous Subarachnoid Hemorrhage in Catalonia, Spain

BACKGROUND

Incidence, clinical course, and fatality of spontaneous subarachnoid hemorrhage (SAH) are evolving, with prevalence of risk factors diminishing, implementation of early detection programs and strategies for priority aneurysm exclusion, technical refinement with less invasive procedures, and improvements in neurocritical care. Modern epidemiological and prognostic data are lacking, especially in southern European and Mediterranean populations.

METHODS

A prospective multicenter observational study on SAH was held in Catalonia, Northeast Spain, from 2020 to 2022 (HSACat project). All public tertiary hospitals participated in a common registry. Primary end points were functional outcomes (modified Rankin Scale) and mortality at 12 months. Secondary aims included epidemiological data, passage of patients between referral and tertiary hospitals, diagnostic and treatment delays, and in-hospital complications.

RESULTS

Of 550 SAH cases reported in Catalonia (2020-2022), a complete registry for analysis was available for 474. Death rate was 20.6% during hospital admission and 26.9% at 1 year. Good functional outcome (modified Rankin Scale score 0-2) was observed in 63.4%, 70.1%, and 76.0% at 3, 6, and 12 months. Age at presentation was younger in men, patients who smoked, and patients with hypertension (P < 0.05). The female-to-male ratio was 3:2 except in the nonaneurysmal group. Time from onset to tertiary hospital admission was longer in rural than in metropolitan areas (7.0 hours vs. 4.7 hours, P < 0.01). Aneurysm occlusion in the first 72 hours was achieved in 83.3%; mainly endovascularly (77.5%) followed by microsurgically (19.3%).

CONCLUSIONS

Even when most patients received timely aneurysm treatment, case fatality rates were considerably high. Data provided by the HSACat project may have public health effects and be used to guide prevention programs and screening strategies.

Epidemiological trends of subarachnoid hemorrhage at global, regional, and national level: a trend analysis study from 1990 to 2021

BACKGROUND

Subarachnoid hemorrhage (SAH) is a subtype of hemorrhagic stroke characterized by high mortality and low rates of full recovery. This study aimed to investigate the epidemiological characteristics of SAH between 1990 and 2021.

METHODS

Data on SAH incidence, mortality, and disability-adjusted life-years (DALYs) from 1990 to 2021 were obtained from the Global Burden of Disease Study (GBD) 2021. Estimated annual percentage changes (EAPCs) were calculated to evaluate changes in the age-standardized rate (ASR) of incidence and mortality, as well as trends in SAH burden. The relationship between disease burden and sociodemographic index (SDI) was also analyzed.

RESULTS

In 2021, the incidence of SAH was found to be 37.09% higher than that in 1990; however, the age-standardized incidence rates (ASIRs) showed a decreased [EAPC: -1.52; 95% uncertainty interval (UI) -1.66 to -1.37]. Furthermore, both the number and rates of deaths and DALYs decreased over time. It was observed that females had lower rates compared to males. Among all regions, the high-income Asia Pacific region exhibited the highest ASIR (14.09/100,000; 95% UI 12.30/100,000 - 16.39/100,000) in 2021, with an EPAC for ASIR < 0 indicating decreasing trend over time for SAH ASIR. Oceania recorded the highest age-standardized mortality rates (ASMRs) and age-standardized DALYs rates among all regions in 2021 at values of respectively 8.61 (95% UI 6.03 - 11.95) and 285.62 (95% UI 209.42 - 379.65). The burden associated with SAH primarily affected individuals aged between 50 - 69 years old. Metabolic risks particularly elevated systolic blood pressure were identified as the main risk factors contributing towards increased disease burden associated with SAH when compared against environmental or occupational behavioral risks evaluated within the GBD framework.

CONCLUSIONS

The burden of SAH varies by gender, age group, and geographical region. Although the ASRs have shown a decline over time, the burden of SAH remains significant, especially in regions with middle and low-middle SDI levels. High systolic blood pressure stands out as a key risk factor for SAH. More specific supportive measures are necessary to alleviate the global burden of SAH.

Body composition and rupture risk of intracranial aneurysms

BACKGROUND

Rupture of an intracranial aneurysm resulting in a subarachnoid hemorrhage (SAH) is a life-threatening situation. Obesity is an increasing health challenge associated with numerous comorbidities. However, recent studies have shown a surprising decreased risk of SAH with increasing body mass index (BMI). The aim was to explore associations between other anthropometric variables and the rupture risk of an intracranial aneurysm, which to our knowledge is lacking in present literature.

METHODS

Using a bioelectrical impedance analysis device, we performed body composition analyses on 31 patients admitted with aneurysmal SAH (aSAH) and 28 patients with planned intervention on their unruptured aneurysm. We also collected information on comorbidities and relevant risk factors. Logistic regression was used to explore associations between anthropometric variables and patients with ruptured versus unruptured aneurysms.

RESULTS

Unadjusted estimates showed a significant inverse relationship between body fat percent and aneurysmal rupture (OR [95% CI]: 0.92 [0.86, 0.97], P = 0.009), and between body fat mass and aneurysmal rupture (OR [95% CI]: 0.95 [0.90, 0.99], P = 0.047). These risk relationships remained significant in age- and sex-adjusted analyses for body fat percent (OR [95% CI]: 0.93, [0.87, 0.97], P = 0.028), and body fat mass (OR [95% CI]: 0.95 [0.90, 0.99], P = 0.041).

CONCLUSIONS

In recent studies showing a paradoxical relation between aSAH and obesity, BMI was the only parameter investigated. We further explored this "obesity paradox" and found lower body fat in aSAH patients compared to UIA. Future studies should investigate these relationships in larger samples. Clinical Trial Registration NCT04613427, November 3, 2020, retrospectively registered.

Risk factor synergism in aneurysmal subarachnoid hemorrhage: a cross-sectional study

BACKGROUND

Spontaneous subarachnoid hemorrhage (SAH) accounts for 5-10% of strokes but a disproportionately large amount of stroke-related morbidity. Several risk factors have been described, including smoking, hypertension, increasing age, and female sex.

METHODS

This cross-sectional study examined all patients with aSAH within a nationally representative catchment from 01/01/2017 to 31/12/2020. Patients with aneurysmal SAH were identified from multiple sources, including a prospective database and death records. The population was estimated from projections from a door-to-door census and risk factors from stratified random sampled surveys conducted on a yearly basis. Poisson regression models were used to estimate the incidence and incidence rate ratios (IRRs) for risk factors with 95% confidence intervals (95% CIs).

RESULTS

We identified 875 cases of aSAH in 11,666,807 patient-years of follow-up, which corresponded to a crude incidence of 7.5 per 100,000 patient-years (95% CI 7-8) and a standardized incidence of 6.1/100,000 (95% CI 5.6-6.5). Smoking was the strongest individual risk factor, with a standardized incidence of 24/100,000 (95% CI 20-27) in smokers compared with 2.6/100,000 (2.1-3.2) in non-smokers (age-adjusted IRR 9.2, 95% CI 6.3-13.6). Hypertension (age-adjusted IRR 3.1, 95% CI 2.2-4.3) and female sex (age-adjusted IRR 1.8, 95% CI 1.4-2.3) were also associated with increased incidence. The highest incidence was observed in hypertensive smokers (standardized incidence 63/100,000, 95% CI 41-84), who had a lifetime risk of aSAH of 6.7% (95% CI 5.4-8.1) after age 35. Compared with participants who were non-smokers without hypertension, the age-adjusted IRR in hypertensive smokers was 27.9 (95% CI 15.9-48.8).

CONCLUSION

Smoking is the most prominent individual risk factor for aSAH. Smoking and hypertension appear to interact to increase the risk of aSAH synergistically.

Re-Evaluating Risk Factors, Incidence, and Outcome of Aneurysmal and Non-Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE

Subarachnoid hemorrhage (SAH) is one of the world's most life-threatening types of stroke. SAH can be classified into two main categories, aneurysmal (aSAH) and non-aneurysmal SAH (naSAH). In the present study, we aimed to prospectively evaluate SAH and its subcategories incidences, risk factors, complications, and outcomes in central Iran.

METHODS

All SAH patients diagnosed between 2016 and 2020 were included in Isfahan SAH Registry. Demographic, clinical characteristics, incidence rates (based on age categories), and laboratory/imaging findings were collected and compared between aSAH and naSAH subgroups. Complications during hospital stay and outcomes were also analyzed. Binary logistic regression analysis was performed to investigate the predictors of aSAH versus naSAH. Kaplan-Meier curves and Cox regression were used to evaluate the survival probability.

RESULTS

A total of 461 SAH patients were included through Isfahan SAH Registry. The SAH annual incidence rate was 3.11 per 100,000 person-years. aSAH had higher incidence rate than naSAH (2.08/100,000 vs. 0.9/100,000 person-years, respectively). In-hospital mortality was 18.2%. Hypertension (P = 0.003) and smoking (P = 0.03) were significantly associated with aSAH, whereas diabetes mellitus (P < 0.001) was more associated with naSAH. After Cox regression analysis, there were higher hazard ratios for reduced in-hospital survival in conditions including altered mental status, Glasgow Coma Scale ≤13, rebleeding, and seizures.

CONCLUSIONS

This study provided an updated estimation of SAH and its subgroups incidences in central Iran. Risk factors for aSAH are comparable to the ones reported in the literature. It is noteworthy that diabetes mellitus was associated with a higher incidence of naSAH in our cohort.

The weekend effect in aneurysmal subarachnoid haemorrhage: a single centre experience and review

Clinical outcomes for patients admitted to hospital during weekend hours have been reported to be poorer than for those admitted during the week. Aneurysmal subarachnoid haemorrhage (aSAH) is a devastating form of haemorrhagic stroke, with a mortality rate greater than 30%. A number of studies have reported higher mortality for patients with aSAH who are admitted during weekend hours. This study evaluates the effect of weekend admission on patients in our unit with aSAH in terms of time to treatment, treatment type, rebleeding rates, functional outcome, and mortality. We analysed a retrospective database of all patients admitted to our tertiary referral centre with aneurysmal subarachnoid haemorrhage between February 2016 and February 2020. Chi-square tests and t-tests were used to compare weekday and weekend demographic and clinical variables. Univariate and multivariate logistic regression analyses were performed to assess for any association between admission during weekend hours and increased neurological morbidity (assessed via Glasgow Outcome Scale at 3 months) and mortality. Of the 571 patients included in this study, 191 were admitted during on-call weekend hours. There were no significant differences found in time to treatment, type of treatment, rebleeding rates, neurological morbidity, or mortality rates between patients admitted during the week and those admitted during weekend hours. Weekend admission was not associated with worsened functional outcome or increased mortality in this cohort. These results suggest that provision of 7-day cover by vascular neurosurgeons and interventional neuroradiologists in high-volume centres could mitigate the weekend effect sometimes reported in the aSAH cohort.

Predictive factors for pre-intervention rebleeding in aneurysmal subarachnoid haemorrhage: a systematic review and meta-analysis

Rebleeding before intervention is a devastating complication of aneurysmal subarachnoid haemorrhage (aSAH). It often occurs early and is associated with poor outcomes. We present a systematic review and meta-analysis to identify potential predictors of rebleeding in aSAH. A database search identified studies detailing the occurrence of pre-intervention rebleeding in aSAH, and 809 studies were screened. The association between rebleeding and a variety of demographic, clinical, and radiological factors was examined using random effects meta-analyses. Fifty-six studies totalling 33,268 patients were included. Rebleeding occurred in 3,223/33,268 patients (11.1%, 95%CI 9.4-13), with risk decreasing by approximately 0.2% per year since 1981. Systolic blood pressure (SBP) during admission was higher in patients who rebled compared with those who did not (MD 7.4 mmHg, 95%CI 2.2 - 12.7), with increased risk in cohorts with SBP > 160 mmHg (RR 2.12, 95%CI 1.35-3.34), but not SBP > 140 mmHg. WFNS Grades IV-V (RR 2.05, 95%CI 1.13-3.74) and Hunt-Hess grades III-V (RR 2.12, 95%CI 1.38-3.28) were strongly associated with rebleeding. Fisher grades IV (RR 2.24, 95%CI 1.45-3.49) and III-IV (RR 2.05, 95%CI 1.17-3.6) were also associated with an increased risk. Awareness of potential risk factors for rebleeding is important when assessing patients with aSAH to ensure timely management in high-risk cases. Increased SBP during admission, especially > 160 mmHg, poorer clinical grades, and higher radiological grades are associated with an increased risk. These results may also aid in designing future studies assessing interventions aimed at reducing the risk of rebleeding.

Trends in Admissions and Outcomes for Treatment of Aneurysmal Subarachnoid Hemorrhage in the United States

BACKGROUND

Lifestyle modifications and advances in surgical and endovascular techniques for treating unruptured intracranial aneurysm (UIA) have vastly evolved over the last few decades and may have reduced the incidence of aneurysmal subarachnoid hemorrhage (aSAH). However, the actual impact of these changes on the rates and outcomes of aSAH remain unexplored. Thus, we studied national aSAH admissions and outcome trends and changes of major risk factors over time.

METHODS

We queried the National Inpatient Sample between 2006 and 2018 to identify adult patients admitted and treated for UIA or ruptured aneurysm with aSAH. The Cochran-Armitage test was conducted to assess the linear trend of proportion of prevalence, inpatient mortality, hypertension, and current smoking status among aSAH admissions. Multivariable logistic regression was conducted to assess the odds of presenting with aSAH versus UIA, in addition to the odds of inpatient mortality among patients with aSAH.

RESULTS

A total of 159,913 patients presented with UIA and 133,567 presented with aSAH. Admissions for aSAH decreased by 0.97% (p < 0.001) per year. Current smoking and hypertension were associated with higher odds of being admitted for aSAH compared with the treatment for UIA (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.29-1.48; OR 1.15, 95% CI 1.08-1.22, respectively). Compared with White patients, Black patients (OR 1.32, 95% CI 1.21-1.43), Hispanic patients (OR 1.38, 95% CI 1.25-1.52), and patients of other races and/or ethnicities (OR 1.73, 95% CI 1.54-1.95) had a higher chance of presenting with aSAH. Rates of inpatient mortality among aSAH admissions showed no change over time (p = 0.21). Among patients admitted with aSAH, current smoking and hypertension showed an upward trend of 0.58% (p < 0.001) and 1.60% (p < 0.001) per year, respectively.

CONCLUSIONS

Despite a downward trend in the annual frequency of hospitalizations for aSAH, inpatient mortality rates for patients undergoing treatment of the ruptured aneurysm have remained unchanged in the United States. Smoking and hypertension are increasingly prevalent among patients with aSAH. Thus, efforts to control these modifiable risk factors must be further strengthened.

Endocrine dysregulation in aneurysmal subarachnoid haemorrhage

INTRODUCTION

Aneurysmal Subarachnoid haemorrhage (aSAH) is one of the most common causes of neurocritical care admission. Consistent evidence has been suggestive of endocrine dysregulation in aSAH. This review aims to provide an up-to-date presentation of the available evidence regarding endocrine dysregulation in aneurysmal subarachnoid haemorrhage.

METHODS

A comprehensive literature search was performed using PubMed database. All available evidence related to endocrine dysregulation in hypothalamic-pituitary hormones, adrenal hormones and natriuretic peptides after aSAH, published since 2010, were reviewed.

RESULTS

There have been reports of varying prevalence of dysregulation in hypothalamic-pituitary and adrenal hormones in aSAH. The cause of this dysregulation and its pattern remain unclear. Hypothalamic-pituitary and adrenal dysregulation have been associated with higher incidence of poor neurological outcome and increased mortality. Whilst there is evidence that long-term dysregulation of these axes may also develop, it appears to be less frequent than the acute-phase dysregulation and transient in pattern. Increased levels of catecholamines have been reported in the hyper-acute phase of aSAH with reported inconsistent correlation with the outcomes and the complications of the disease. There is growing evidence that of a causal link between the endocrine dysregulation and the development of hyponatraemia and delayed cerebral ischaemia, in the acute phase of aSAH. However, the pathophysiological mechanism and pattern of endocrine dysregulation which could be causally associated with these complications still remain debatable.

CONCLUSION

The evidence, mainly from small observational and heterogeneous in methodology studies, is suggestive of adverse effects of the endocrine dysregulation on the outcome and the incidence of complications of the disease. However, the cause of this dysregulation and a pathophysiological mechanism that could link its presence with the development of acute complications and the outcome of the aSAH remain unclear. Further research is warranted to elucidate the clinical significance of endocrine dysregulation in subarachnoid haemorrhage.

The times they are a-changin': increasing complexity of aneurysmal subarachnoid hemorrhages in patients treated from 2004 to 2018

BACKGROUND

Nationwide study results have suggested varying trends in the incidence of aneurysmal subarachnoid hemorrhage (aSAH) over time. Herein, trends over time for aSAH treated at a quaternary care center are compared to low-volume hospitals.

METHODS

Cases were retrospectively reviewed for patients with aSAH treated at our institution. Trend analyses were performed on the number of aSAH hospitalizations, treatment type, Charlson Comorbidity Index (CCI), Hunt and Hess (HH) grade, aneurysm location, aneurysm type, and in-hospital mortality. The National Inpatient Sample (NIS) was queried to compare the CCI scores of our patients with those of patients in low-volume hospitals (<20 aSAH/year) in our census division.

RESULTS

Some 1248 patients (321 during 2004-2006; 927 during 2008-2018) hospitalized with aSAH were treated with endovascular therapy (489, 39%) or microsurgery (759, 61%). A significant downtrend in the annual aSAH caseload occurred (123 patients in 2004, 75 in 2018, p<0.001). A linear uptrend was observed for the mean CCI score of patients (R²=0.539, p<0.001), with no change to in-hospital mortality (R²=0.220, p=0.24). Mean (SD) CCI for small-volume hospitals treating aSAH within our division was significantly lower than that of our patient population (1.8 [1.6] vs 2.1 [2.0]) for 2012-2015.

CONCLUSIONS

A decreasing number of patients were hospitalized with aSAH throughout the study. Compared with patients with aSAH admitted in 2004, those admitted more recently were sicker in terms of preexisting comorbidity and neurologic complexity. These trends could be attributable to the increasing availability of neurointerventional services at smaller-volume hospitals capable of treating healthier patients.

Risk Factors for Cerebral Aneurysm Rupture in Mongolia

Purpose

Identification of country-specific demographic, medical, lifestyle, and geoenvironmental risk factors for cerebral aneurysm rupture in the developing Asian country of Mongolia. First-time estimation of the crude national incidence of aneurysmal subarachnoid hemorrhage (aSAH).

Methods

A retrospective analysis of all intracranial digital subtraction angiographies (DSA) acquired in Mongolia during the 2‑year period 2016–2017 (1714 examinations) was performed. During this period, DSA was used as primary diagnostic imaging modality for acute severe neurological symptoms in the sole hospital nationwide dedicated to neurological patients. The catchment area of the hospital included the whole country. Patients with incidental and ruptured aneurysms were reviewed with respect to their medical history and living conditions. The data was used to install a Mongolian aneurysm registry.

Results

The estimated annual crude incidence of cerebral aneurysm rupture was 6.71 for the country of Mongolia and 14.53 per 100,000 persons for the capital region of Ulaanbaatar. Risk factors common in developed countries also applied for the Mongolian population: A medical history of hypertension, smoking or the presence of multiple aneurysms led to a higher relative risk of rupture. In contrast, female gender was not associated with a higher risk in this national cohort. Males pursuing a traditional nomadic living may exhibit a specifically high risk of rupture.

Conclusion

Disease management of over 200 individuals/year with aSAH constitutes a socioeconomic burden in Mongolia. Efforts to raise awareness of the risk factors hypertension and smoking among the Mongolian population are desirable. Measures to improve the nationwide availability of modern neurovascular treatment options are currently under consideration.

Blood-brain barrier permeability imaging as a predictor for delayed cerebral ischaemia following subarachnoid haemorrhage. A narrative review

BACKGROUND

Aneurysmal subarachnoid haemorrhage is associated with significant morbidity and mortality due to the myriad of complications contributing to early brain injury and delayed cerebral ischaemia. There is increasing interest in the exploration of the association between blood-brain barrier integrity and risks of delayed cerebral ischaemia and poor outcomes. Despite recent advances in cerebral imaging, radiographic imaging of blood-brain barrier disruption, as a biomarker for outcome prediction, has not been adopted in clinical practice.

METHODS

We performed a narrative review by searching for articles describing molecular changes or radiological identification of changes in BBB permeability following subarachnoid haemorrhage (SAH) on MEDLINE. Preclinical studies were analysed if reported structural changes and clinical studies were included if they investigated for radiological markers of BBB disruption and its correlation with delayed cerebral ischaemia.

RESULTS

There is ample preclinical evidence to suggest that there are structural changes in BBB permeability following SAH. The available clinical literature has demonstrated correlations between permeability imaging and outcomes following aneurysmal subarachnoid haemorrhage (aSAH).

CONCLUSION

Radiological biomarkers offer a potential non-invasive prognostication tool and may also allow early identifications of patients who may be at risk of DCI.

Timing of treatment of aneurysmal subarachnoid haemorrhage: are the goals set in international guidelines achievable?

BACKGROUND AND AIMS

International guidelines emphasise the importance of securing ruptured cerebral aneurysms within 48-72 h of ictus. We assessed the timing of treatment of patients with aneurysmal subarachnoid haemorrhage (aSAH) referred to a national neurosurgical centre.

MATERIALS AND METHODS

Analysis of a prospective database of patients with aSAH admitted between 1st of February 2016 and 29th of February 2020 was performed. The timing to treatment was expressed in days and analysed in three ways: ictus to treatment, ictus to referral and referral to treatment. ORs with 95% CI were calculated for aneurysm treatment within 24, 48 and 72 h for good grade (WFSN 1-3) and poor grade (WFNS 4-5) cohorts separately.

RESULTS

Of a total of 538 patients with aSAH, the aneurysm was secured in 312 (58%) within 24 h and in 398 (74%) within 48 h of ictus. Securing the aneurysm within 48 h of ictus was achieved in 89% (395/444) of patients who were referred within 24 h of ictus, but in only 3.2% (3/94) who were referred > 24 h after ictus. Poor grade patients (WFNS 4-5) were more likely than good grade patients (WFNS 1-3) to be referred to neurosurgery within 48 h of ictus (OR 22.87, 95% CI 3.14-166.49, p = 0.0020) and for their aneurysm to be secured within 48 h (OR 1.78, 95% CI 1.06-2.98, p = 0.0297) of ictus. Ictus to referral delay was highest in WFNS grade 1 patients.

CONCLUSIONS

In centres with 7 day per week provision of interventional neuroradiology and vascular neurosurgery, the majority of patients with aSAH can be treated within the timeframes recommended by international guidelines and this applies to all grades of aSAH. However, delays still occur in a significant proportion of patients and this particularly applies to delays in presentation and diagnosis in good grade patients.

Genetically Determined Smoking Behavior and Risk of Nontraumatic Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Animal and observational studies indicate that smoking is a risk factor for aneurysm formation and rupture, leading to nontraumatic subarachnoid hemorrhage (SAH). However, a definitive causal relationship between smoking and the risk of SAH has not been established. Using Mendelian randomization (MR) analyses, we tested the hypothesis that smoking is causally linked to the risk of SAH.

METHODS

We conducted a 1-sample MR study using data from the UK Biobank, a large cohort study that enrolled over 500 000 Britons aged 40 to 69 from 2006 to 2010. Participants of European descent were included. SAH cases were ascertained using a combination of self-reported, electronic medical record, and death registry data. As the instrument, we built a polygenic risk score using independent genetic variants known to associate (P<5×10^-8) with smoking behavior. This polygenic risk score represents the genetic susceptibility to smoking initiation. The primary MR analysis utilized the ratio method. Secondary MR analyses included the inverse variance weighted and weighted median methods.

RESULTS

A total of 408 609 study participants were evaluated (mean age, 57 [SD 8], female sex, 220 937 [54%]). Among these, 132 566 (32%) ever smoked regularly, and 904 (0.22%) had a SAH. Each additional SD of the smoking polygenic risk score was associated with 21% increased risk of smoking (odds ratio [OR], 1.21 [95% CI, 1.20-1.21]; P<0.001) and a 10% increased risk of SAH (OR, 1.10 [95% CI, 1.03-1.17]; P=0.006). In the primary MR analysis, genetic susceptibility to smoking was associated with a 63% increase in the risk of SAH (OR, 1.63 [95% CI, 1.15-2.31]; P=0.006). Secondary analyses using the inverse variance weighted method (OR, 1.57 [95% CI, 1.13-2.17]; P=0.007) and the weighted median method (OR, 1.74 [95% CI, 1.06-2.86]; P=0.03) yielded similar results. There was no significant pleiotropy (MR-Egger intercept P=0.39; MR Pleiotropy Residual Sum and Outlier global test P=0.69).

CONCLUSIONS

These findings provide evidence for a causal link between smoking and the risk of SAH.

Smoking habits and detection rate of unruptured intracranial aneurysms and incidence rate of subarachnoid haemorrhage in Norway between 2008 and 2015

Objective

The aim of this study was to investigate the detection rate of unruptured intracranial aneurysms (UIAs) and incidence of aneurysmal subarachnoid haemorrhage (SAH) in relation to the rapidly changing smoking rates in Norway between 2008 and 2015.

Methods

The registry-based study included all patients (≥ 16 years old) admitted to a hospital in Norway between 2008 and 2015 with a primary diagnosis of aneurysmal SAH or an outpatient diagnosis of UIAs. Age group–specific and total detection rate of UIAs and incidence rate of SAH over the years were calculated. Age group–specific data on smoking habits was retrieved from a national annual survey representative of the whole Norwegian population.

Results

The rate of daily smokers decreased by 48% between 2008 and 2015. The detection rate of UIAs decreased by 47% from 17.3 in 2008 to 9.3 per 100,000 persons in 2015, and the incidence of SAH decreased by 30% from 11.3 in 2008 to 7.9 per 100,000 persons in 2015. The average annual decline in prevalence of daily smoking, UIA detection rate, and SAH incidence was 6.9%, 6.7%, and 4.3% per year, respectively. Multinomial logistic regression analyses revealed that the correlation between the decline in estimated daily smoking rates and decline in detection rate of UIAs (hazard ratio 52.5 CI = (14.9,∞), p < 0.00001) and incidence of SAH (hazard ratio 11.8 CI=(5.6,32.5), p < 0.00001) are statistically significant. The association is particularly strong in young and middle-aged cohorts (< 66 years old).

Conclusion

It is likely that reducing cigarette smoking on a population-based level strongly reduces the rates of UIAs and SAH.

Abdominal aortic aneurysm is associated with subarachnoid hemorrhage

BACKGROUND

Although intracranial aneurysms (IA) and abdominal aortic aneurysms (AAA) share similar risk factors, little is known about the relationship between them. Previous studies have shown an increased incidence of IA in patients with AAA, though the rate of subarachnoid hemorrhage (SAH) in patients with AAA has not been described.

OBJECTIVE

To use claims data with longitudinal follow-up, to evaluate the incidence of aneurysmal SAH in patients diagnosed with AAA.

METHODS

We examined longitudinally linked medical claims data from a large private insurer to determine rates of aneurysmal SAH (aSAH) and secured aSAH (saSAH) in 2004-2014 among patients with previously diagnosed AAA.

RESULTS

We identified 62 910 patients diagnosed with AAA and compared them 5:1 with age- and sex-matched controls. Both populations were predominantly male (70.9%), with an average age of 70.8 years. Rates of hypertension (69.7% vs 50.6%) and smoking (12.8% vs 4.1%) were higher in the AAA group (p<0.0001) than in controls. Fifty admissions for aSAH were identified in patients with AAA (26/100 000 patient-years, 95% CI 19 to 44) and 115 admissions for aSAH in controls (7/100 000 years, 95% CI 6 to 9), giving an incidence rate ratio (IRR) of 3.6 (95% CI 2.6 to 5.0, p<0.0001) and a comorbidity-adjusted incidence rate ratio (IRR) of 2.8 (95% CI 1.9 to 3.9) for patients with AAA. The incidence of secured aneurysmal SAH was proportionally even higher in patients with AAA, 7 vs 2/100 000 years, IRR 4.5 (95% CI 3.2 to 6.3, p<0.0001).

CONCLUSION

SAH rate was elevated in patients with AAA, even after adjustment for comorbidities. Among risk factors evaluated, AAA was the strongest predictor for SAH. The relative contributions of common genetic and environmental risk factors to both diseases should be investigated.

Population-based stroke surveillance using big data: state-wide epidemiological trends in admissions and mortality in New South Wales, Australia

OBJECTIVES

Epidemiological trends for major causes of death and disability, such as stroke, may be monitored using administrative data to guide public health initiatives and service delivery.

METHODS

We calculated admissions rates for ischaemic stroke, intracerebral haemorrhage and subarachnoid haemorrhage between 1 January 2005 and December 31^st, 2013 and rates of 30-day mortality and 365-day mortality in 30-day survivors to 31 December 2014 for patients aged 15 years or older from New South Wales, Australia. Annual Average Percentage Change in rates was estimated using negative binomial regression.

RESULTS

Of 81,703 eligible admissions, 64,047 (78.4%) were ischaemic strokes and 13,302 (16.3%) and 4,778 (5.8%) were intracerebral and subarachnoid haemorrhages, respectively. Intracerebral haemorrhage admissions significantly declined by an average of 2.2% annually (95% Confidence Interval = -3.5% to -0.9%) (p < 0.001). Thirty-day mortality rates significantly declined for ischaemic stroke (Average Percentage Change -2.9%, 95% Confidence Interval = -5.2% to -1.0%) (p = 0.004) and subarachnoid haemorrhage (Average Percentage Change = -2.6%, 95% Confidence Interval = -4.8% to -0.2%) (p = 0.04). Mortality at 365-days amongst 30-day survivors of ischaemic stroke and intracerebral haemorrhage was stable over time and increased in subarachnoid haemorrhage (Annual Percentage Change 6.2%, 95% Confidence Interval = -0.1% to 12.8%), although not significantly (p = 0.05).

DISCUSSION

Improved prevention may have underpinned declining intracerebral haemorrhage rates while survival gains suggest that innovations in care are being successfully translated. Mortality in patients surviving the acute period is unchanged and may be increasing for subarachnoid haemorrhage warranting investment in post-discharge care and secondary prevention.

The role and therapeutic potential of heat shock proteins in haemorrhagic stroke

Heat shock proteins (HSPs) are induced after haemorrhagic stroke, which includes subarachnoid haemorrhage (SAH) and intracerebral haemorrhage (ICH). Most of these proteins function as neuroprotective molecules to protect cerebral neurons from haemorrhagic stroke and as markers to indicate cellular stress or damage. The most widely studied HSPs in SAH are HSP70, haeme oxygenase-1 (HO-1), HSP20 and HSP27. The subsequent pathophysiological changes following SAH can be divided into two stages: early brain injury and delayed cerebral ischaemia, both of which determine the outcome for patients. Because the mechanisms of HSPs in SAH are being revealed and experimental models in animals are continually maturing, new agents targeting HSPs with limited side effects have been suggested to provide therapeutic potential. For instance, some pharmaceutical agents can block neuronal apoptosis signals or dilate cerebral vessels by modulating HSPs. HO-1 and HSP70 are also critical topics for ICH research, which can be attributed to their involvement in pathophysiological mechanisms and therapeutic potential. However, the process of HO-1 metabolism can be toxic owing to iron overload and the activation of succedent pathways, for example, the Fenton reaction and oxidative damage; the overall effect of HO-1 in SAH and ICH tends to be protective and harmful, respectively, given the different pathophysiological changes in these two types of haemorrhagic stroke. In the present study, we focus on the current understanding of the role and therapeutic potential of HSPs involved in haemorrhagic stroke. Therefore, HSPs may be potential therapeutic targets, and new agents targeting HSPs are warranted.