Incidence Of Aneurysmal Subarachnoid Hemorrhage Research Articles

Meteorological Influences on the Incidence of Aneurysmal Subarachnoid Hemorrhage – A Single Center Study of 511 Patients

ObjectiveTo assess the potential meteorological influence on the incidence of aneurysmal subarachnoid hemorrhage (SAH). Previous studies used inhomogeneous patient groups, insufficient study periods or inappropriate statistics.Patients and MethodsWe analyzed 511 SAH admissions between 2004 and 2012 for which aneurysmal rupture occurred within the Zurich region. The hourly meteorological parameters considered are: surface pressure, 2-m temperature, relative humidity and wind gusts, sunshine, and precipitation. For all parameters we investigate three complementary statistical measures: i) the time evolution from 5 days before to 5 days after the SAH occurrence; ii) the deviation from the 10-year monthly mean; and iii) the change relative to the parameter's value two days before SAH occurrence. The statistical significance of the results is determined using a Monte Carlo simulation combined with a re-sampling technique (1000×).ResultsRegarding the meteorological parameters considered, no statistically significant signal could be found. The distributions of deviations relative to the climatology and of the changes during the two days prior to SAH events agree with the distributions for the randomly chosen days. The analysis was repeated separately for winter and summer to exclude compensating effects between the seasons.ConclusionBy using high-quality meteorological data analyzed with a sophisticated and robust statistical method no clearly identifiable meteorological influence for the SAH events considered can be found. Further studies on the influence of the investigated parameters on SAH incidence seem redundant.

Unruptured Intracranial Aneurysms in the Norwegian Nord-Trøndelag Health Study (HUNT)

Rupture risk of unruptured intracranial aneurysms (UIAs) has been investigated in studies observing the natural history of this condition. Such studies have been prone to selection bias that may influence the results. To calculate the overall rupture risk from data on the prevalence of UIA, which constitutes the population at risk, and the incidence of aneurysmal subarachnoid hemorrhage (aSAH) in the same population. Data were collected from the Norwegian Nord-Trøndelag Health Study (HUNT), a large population-based cohort study. The prevalence of UIAs was estimated by performing magnetic resonance angiography in 1006 randomly selected volunteers 50 to 65 years of age from this population cohort. The incidence of aSAH was investigated by searching national and hospital registers with thorough case ascertainment to avoid inclusion of nonaneurysmal subarachnoid hemorrhage. The prevalence of UIAs was 1.9% and incidence of aSAH was 16.4 per 100,000 person-years. Based on these figures, the overall rupture risk in the 50- to 65-year age group in the HUNT population is 0.87% per year. This is the first study to estimate rupture risk of intracranial aneurysms from epidemiologic data in a large population-based cohort. This study design is less prone to selection bias and may provide an important supplement to the existing literature of studies of natural history of UIAs.

Impact of the moon on cerebral aneurysm rupture

Several external and internal risk factors for cerebral aneurysm rupture have been identified to date. Recently, it has been reported that moon phases correlate with the incidence of aneurysmal subarachnoid hemorrhage (SAH), however, another author found no such association. Therefore, the present study investigates the influence of the lunar cycle on the incidence of aneurysmal rupture, the initial clinical presentation, and the amount of subarachnoid blood. Lunar phase and the particular day of the lunar cycle were correlated to the date of aneurysm rupture, aneurysm location, initial clinical presentation, and amount of subarachnoid blood assessed from CT scans of all patients treated for basal SAH in our department from 2003 to 2010. We found no correlation between incidence of aneurysmal SAH, location of the aneurysm, initial clinical presentation, or amount of subarachnoid blood and the lunar cycle. The moon influences neither the incidence of aneurysmal SAH nor the grade of initial neurological deterioration or amount of subarachnoid blood.

Seasonal Variation in the Incidence of Aneurysmal Subarachnoid Hemorrhage Associated with Age and Gender: 20-Year Results from the Yamaguchi Cerebral Aneurysm Registry

Background: This study was a cerebral aneurysm registry study conducted in a region with few climatic differences. Based on data collected for over 20 years, seasonal variations and characteristics of subarachnoid hemorrhage (SAH) due to ruptured aneurysms were analyzed. Methods: This study included 5,007 patients in the Yamaguchi Prefecture with aneurysmal SAH between 1986 and 2005. Incidence rates by month, sex, age, severity, and aneurysm site were analyzed. Results: In women, seasonal variation was observed, in particular among those aged ≥50 years. Among those aged 50-69 years, the highest incidence was in October, and the nadir was in June (peak-to-trough ratio = 1.72). At age ≥70 years, this was slightly different, with the highest incidence in December and the nadir in July (peak-to-trough ratio = 1.48). However, there was no seasonal variation in men overall; it was limited to elderly men at age ≥70 years, with the highest incidence in January and the nadir in July (peak-to-trough ratio = 2.9). Aneurysm site and severity showed no relationship with seasonal variation. Conclusion: The present study shows seasonal variations in the onset of SAH. Seasonal variations in SAH differed depending on age and sex.

Lifetime risks for aneurysmal subarachnoid haemorrhage: multivariable risk stratification

ObjectiveThe overall incidence of aneurysmal subarachnoid haemorrhage (aSAH) in western populations is around 9 per 100 000 person-years, which confers to a lifetime risk of around half per cent. Risk...

Unresolved Issues in the Management of Aneurysmal Subarachnoid Hemorrhage

A cerebral aneurysm is an outpouching of a weakened arterial wall, usually at a bifurcation of one of the larger vessels of the Circle of Willis. When the outpouching ruptures, arterial pressure forces blood into the subarachnoid space. The annual incidence of aneurysmal subarachnoid hemorrhage is 8 to 10 per 100 000 in the United States. The outcome varies for this patient population. New management strategies have emerged; some practices are evidence based, whereas others are based on anecdotal experiences. This variation has resulted in a number of unresolved issues in caring for patients with an aneurysmal subarachnoid hemorrhage. This article discusses some of these unresolved issues, including the use of medications such as nimodipine, antifibrinolytics, statins, and magnesium; coiling or clipping for aneurysm securement; and the prevention and treatment of potential complications. Critical care nurses must conduct detailed assessments and provide complex care to optimize patient outcomes.

Unresolved Issues in the Management of Aneurysmal Subarachnoid Hemorrhage

A cerebral aneurysm is an outpouching of a weakened arterial wall, usually at a bifurcation of one of the larger vessels of the Circle of Willis. When the outpouching ruptures, arterial pressure forces blood into the subarachnoid space. The annual incidence of aneurysmal subarachnoid hemorrhage is 8 to 10 per 100 000 in the United States. The outcome varies for this patient population. New management strategies have emerged; some practices are evidence based, whereas others are based on anecdotal experiences. This variation has resulted in a number of unresolved issues in caring for patients with an aneurysmal subarachnoid hemorrhage. This article discusses some of these unresolved issues, including the use of medications such as nimodipine, antifibrinolytics, statins, and magnesium; coiling or clipping for aneurysm securement; and the prevention and treatment of potential complications. Critical care nurses must conduct detailed assessments and provide complex care to optimize patient outcomes.

Increased Incidence of Aneurysmal Subarachnoid Hemorrhage on Sundays and Mondays in 1,862 Patients from Eastern Finland

Background: Temporal patterns of aneurysmal subarachnoid hemorrhage (aSAH) from saccular intracranial aneurysm (sIA) were studied in a consecutive series of 1,862 patients. Methods: Neurosurgery of Kuopio University Hospital (KUH) solely serves a defined catchment population in Eastern Finland. Kuopio’s sIA database contains 1,596 sporadic and 266 familial patients admitted to KUH within 72 h from the onset of aSAH between 1980 and 2007. The distributions by the weekday of the onset of aSAH, admission to KUH, and occlusive therapy of the ruptured sIA were analyzed. Logistic regression was used to search for clinical variables (patients, sIA disease, clinical condition) that would independently correlate with each distribution. Results: The onset of aSAH occurred significantly most often (p < 0.001) on Sundays (n = 330) and Mondays (n = 309) and least frequently on Saturdays (n = 231). None of the clinical variables tested associated significantly and independently with the Sunday and Monday peaks. The admissions to KUH after aSAH were most frequent (p < 0.001) on Mondays (n = 331) and least frequent on Thursdays (n = 221) and Saturdays (n = 221). Overall, 1,655 patients underwent occlusive therapy, most frequently on Mondays (n = 318) and least frequently on Saturdays (n = 189) and Sundays (n = 197). Conclusions: Sundays and Mondays were the most frequent and Saturdays the least frequent days of aSAH in a defined Eastern Finnish population. We could not identify any etiology to this temporal pattern. Binge drinking is frequent in Finland, especially among young males, but age and gender did not correlate with the Sunday and Monday peaks.

Impact of Ultra-early Coiling on Clinical Outcome after Aneurysmal Subarachnoid Hemorrhage in Elderly Patients

The incidence of aneurysmal subarachnoid hemorrhage is increasing in the elderly as life expectancy increases. The purpose of this study was to analyze whether ultra-early coiling of ruptured intracranial aneurysms improves clinical outcomes in elderly patients. Records of patients (aged ≥ 70 years) with aneurysmal subarachnoid hemorrhage treated with endovascular coiling were retrieved. Patients were classified into two groups: group A (patients coiled within 24 hours of subarachnoid hemorrhage) and group B (patients coiled ≥24 hours after subarachnoid hemorrhage). For each group, patient demographics, World Federation of Neurological Surgeons clinical grade, Fisher computed tomographic grade, aneurysm characteristics, and clinical outcomes were recorded. Outcomes were measured using the Modified Rankin Scale at 6 months. Fifty-six patients were coiled within 24 hours of subarachnoid hemorrhage (group A) and 40 patients at ≥24 hours after subarachnoid hemorrhage (group B). Groups A and B had similar clinical and angiographic characteristics. Clinical outcomes showed that a total of 87.5% of patient (49 of 56) in group A were independent (Modified Rankin Scale score 0-2) compared with 70.0% of patients (28 of 40) in group B (P = .034). In multivariate logistic regression analysis, ultra-early coiling (odds ratio, 3.860; 95% confidence interval, 1.125-13.249; P = .032) proved to be an independent predictor of better clinical outcome (Modified Rankin Scale score 0-2). Ultra-early (<24 hours after subarachnoid hemorrhage) coiling of ruptured aneurysms was marginally associated with improved clinical outcomes compared to coiling at ≥24 hours in elderly patients. Larger, prospective studies are required to adequately assess outcome differences between these two groups.

Incidence and mortality of aneurysmal subarachnoid hemorrhage in two Norwegian cohorts, 1984–2007

The incidence of aneurysmal subarachnoid hemorrhage (aSAH) ranges from 4 to 10 per 100,000 person-years in most countries, and 30-day case fatality is high. The aim of this study was to estimate the incidence and case fatality of aSAH and to assess preictal predictors of survival in 2 large Norwegian population-based cohort studies. A total of 94,976 adults (≥20 years) in the Nord-Trøndelag Health Study and 31,753 participants (aged ≥20 years) in the Tromsø Study were included. During follow-up, aSAHs were identified, incidence rates were estimated, and predictors of survival were assessed using Cox and Poisson regression analysis. A total of 214 patients with aSAH were identified during 2,077,927 person-years of follow-up from 1984 to 2007. The incidence rate was 10.3 per 100,000 person-years: 13.3 for women and 7.1 for men. The incidence increased by 2% (95% confidence interval [CI] 0-4) per 5-year time period. Case fatality at 3, 7, and 30 days was 20%, 24%, and 36%. Thirty-day case fatality remained stable during follow-up (odds ratio 1.01, 95% CI 0.97-1.06 per year). Never smokers had poorer survival after aSAH than current and former smokers combined (hazard ratio 1.6, 95% CI 0.9-2.9). The slight increase in incidence of aSAH over time may be explained by differences in diagnostic procedures. Case fatality remained stable during 23 years of follow-up.

What Is the Real Incidence of Aneurysmal Subarachnoid Hemorrhage in the Middle East? A Preliminary Multicenter Study in Iran

71 (49.7%) 72 (50.3%) 143 (100%) Aneurysm 57 (80.3%) 40 (55.6%) 97 (68%) AVM — 3 (4.2%) 3 (2%) HTN 12 (16.90%) 17 (23.61%) 27 (18.88%) Unknown 2 (2.81%) 12 (16.66%) 14 (9.79%)

Intracranial aneurysms: new aspects of formation, rupture and outcome

Rupture of an intracranial aneurysm (IA) and subarachnoid haemorrhage (SAH) is still one of the most feared neurological diseases. The incidence of aneurysmal SAH is 6–15/100000/year with a 30-day case fatality of 30–50%. About 50% of survivors are disabled. Although SAH only represents the third most common cause of stroke, because of the poor outcome after the haemorrhage and the young age at which it occurs, the loss of productive life years from SAH is as large as that from ischaemic stroke and the estimated lifetime costs are more than double that of ischaemic stroke [1]. The prevalence of unruptured IAs of 2% in the general population has been confirmed by recent MRI studies of healthy volunteers and represents a common incidental finding when patients are sent to MRI scanning for unspecific complaints such as headache, vertigo, dizziness or others. Still, management of these incidental findings is a controversial topic and the decision of whether to “waitand-scan” or to treat the patient by microsurgical clipping or endovascular coiling is based on weak data and highly individualised.

破裂脳動脈瘤の治療成績 高齢者の破裂脳動脈瘤に対する，単一施設における治療成績の検討

The incidence of aneurysmal subarachnoid hemorrhage (SAH) increases with age. Aged patients of SAH are thought to have higher risk for complications and poorer prognosis. We retrospectively reviewed the consecutive medical records of ruptured intracranial aneurysm patients over 75 years old (y/o), who were admitted to our hospital, where endovascular treatment was adopted as the first option between April 2004 and July 2010. Thirty-eight patients (6 males and 32 females) ranging from 75 to 90 (average 82.1) y/o were enrolled. They were divided into a course observation (CO) group (n=7), clipping (CL) group (n=13) and coil embolization (CE) group (n=18). Among these 3 groups, we evaluated the clinical characteristics, Hunt & Kosnik (H&K) grade on admission, and modified Rankin Scale (mRS) and Glasgow Outcome Scale (GOS) 3 months after ictus as the outcomes. Furthermore, we analyzed the main cause leading to unfavorable outcomes. According to the location of radically treated aneurysms, all MCA aneurysms were clipped and all VBA aneurysms were coil embolized, while ACoA aneurysms were more likely to be treated with coil embolization. Although it was necessary in some cases to alter the approach route from trans-femoral to trans-brachial or trans-carotid due to atherosclerotic tortuosity, every coil embolization was successful without procedure-related complications. Moreover, neither re-rupture nor re-growth requiring further treatment occurred during follow-up period (range, 6 months–6 years). Among the CL group and CE group, 20 (64.5%) of 31 resulted in mRS 3–6 despite aggressive treatment. However, the results of the CO group were much worse than those of the CL group and CE group. All 7 patients in the CO group died of primary brain damage (PBD) 3, re-rupture 3, pneumonia 1, respectively. There was no significant difference between the CL group and CE group in age distribution or H&K grade. Nevertheless, the proportion of mRS 0 and 1 in the CE group was larger than that in the CL group (44.4% vs. 23.1%), although there was no statistical difference. No vegetative survival (V) was found in this study, so we regarded severely disabled (SD) and dead (D) as unfavorable outcomes. There were 6 SD and 3 D of 13 in the CL group, whereas there were 7 SD and 3 D of 18 in the CE group. As the main cause of unfavorable outcomes, PBD, systematic complications such as pneumonia, pre-existing comorbidities etc. were named, but above all, vasospasm was strongly correlated with SD in the CL group (4 of 6) compared with the CE group (2 of 7). Though there were inherent limitations and biases in this study and the overall results were unsatisfactory, we validated the usefulness of coil embolization for ruptured aneurysm in elderly patients. Because coil embolization was effective against re-rupture, it might be a preferred alternative for aneurysms not amenable to clipping. Optimum treatment should be considered individually when both microsurgical and endovascular treatment modalities are available. Furthermore, intensive peri-procedural management of patients’ clinical conditions especially focused on preventing vasospasm as well as greater skill in both treatments are important to improve outcomes.

Incidence of aneurysmal subarachnoid hemorrhage in Norway, 1999-2007

To investigate changes and regional variations in annual incidence rates of aneurysmal subarachnoid hemorrhage (SAH) in Norway between 1999 and 2007. The authors retrospectively reviewed data from the Norwegian Patient Register for the period 1999-2007. Crude incidence of aneurysmal SAH was 10.0/100,000 person years [95% CI (confidence interval): 9.7-10.3] and was higher in women (12.0/100,000 person years; 95% CI: 11.5-12.5) than men (8.1/100,000 person years; 95% CI: 7.7-8.4). Decreasing annual incidence rates were observed from 11.1/100,000 person years (95% CI: 10.5-11.6) in the period 1999-2001 to 8.9/100,000 person years (95% CI: 8.4-9.4) in the period 2005-2007 (P for trend <0.001). Regional variations were observed, from 8.4/100,000 person years (95% CI: 7.7-9.00) in the southern region, 10.4/100,000 person years (95% CI: 9.5-11.2) in the central region and 11.9/100,000 person years (95% CI: 10.8-12.9) in the northern region. Incidence of aneurysmal SAH in Norway decreased from 1999 to 2007, with significant regional variations indicating an increasing gradient from south to north.

A 5-year retrospective study assessing the association between seasonal and meteorological change and incidence of aneurysmal subarachnoid haemorrhage

Objective. Seasonal variation in incidence of spontaneous subarachnoid haemorrhage (SAH) is well recognised. This retrospective single-centre study aimed to characterise seasonality of SAH in the temperate climate of London, UK and to determine associations of incidence with meteorological variables. We further investigated whether associations vary according to location of aneurysm.Methods. Admission data on 647 patients admitted with spontaneous SAH from December 2003 to August 2008 was analysed using our neurosurgical referrals database. Average monthly incidence of SAH was correlated with local temperature, atmospheric pressure and humidity data. In a subset of 467 patients, impact of aneurysm location on seasonal variation was evaluated.Results. A non-significant bi-annual peak incidence was observed in Spring and Autumn with a trough in Summer (χ2 = 1.5, p = 0.47). This trend was particularly marked with middle cerebral and posterior communicating artery aneurysms. However, anterior communicating artery aneurysmal SAH peaked in Summer only. SAH incidence correlated significantly with average humidity (coefficient 0.213, CI (0.02–0.404), p = 0.035) and peak humidity (coefficient 0.128, CI (0.008–0.248), p = 0.041). Temperature and atmospheric pressure did not correlate with incidence.Conclusions. This study illustrates a pattern of variation in SAH incidence similar to that seen in other populations and climates. However, our data suggests that this pattern differs according to aneurysm location. Unusually, we also find that humidity, and not temperature or atmospheric pressure, correlates with SAH incidence. Seasonal variability in aneurysm rupture is likely to be multifactorial, but meteorological factors may play an important role.

Incidence of Aneurysmal Subarachnoid Hemorrhage and Analysis of Factors Involved in Early Aneurysm Rebleeding

Incidence of Aneurysmal Subarachnoid Hemorrhage and Analysis of Factors Involved in Early Aneurysm Rebleeding

Risk Factors for Aneurysmal Subarachnoid Hemorrhage in a Prospective Population Study

The morbidity and mortality of subarachnoid hemorrhage (SAH) are high, and established risk factors are scarce. We prospectively assessed the association of blood pressure, smoking, and body mass with the risk of aneurysmal SAH. All residents >or=20 years were invited to the Nord-Trøndelag Health (HUNT) Study (1984 to 1986) and 74,977 (88.1%) attended. The study included standardized measurements of blood pressure, body weight and height, and self-administered questionnaires. Participants who later had aneurysmal SAH (n=132) were identified, and hazard ratios (HRs), adjusted for age and sex, were estimated using Cox regression analysis. The crude annual incidence of aneurysmal SAH was 9.9 per 100,000 people; the incidence was almost twice as high in women as in men (12.9 versus 6.8, P=0.001). Systolic blood pressure was positively associated with risk (P for trend=0.001). Compared with the reference (<130 mm Hg), the adjusted HR in people with systolic blood pressure of 130 to 139 mm Hg was 2.3 (95% CI, 1.4 to 3.8) and for systolic blood pressure >170 mm Hg, the HR was 3.3 (95% CI, 1.7 to 6.3). Diastolic pressure showed similar positive associations. Compared with never smokers, former (HR, 2.7; 95% CI, 1.4 to 5.1) and current (HR, 6.1; 95% CI, 3.6 to 10.4) smokers had substantially higher risk. Compared with normal weight (body mass index, 18.5 to 24.9 kg/m(2)), overweight people were at lower risk (HR, 0.6; 95% CI, 0.4 to 1.0). Systolic and diastolic blood pressure were strong predictors of aneurysmal SAH, and there was a substantially increased risk associated with smoking. However, high body mass was associated with reduced risk of aneurysmal SAH.

Impact of the lunar cycle on the incidence of aneurysmal subarachnoid haemorrhage: Myth or reality?

Objective To investigate the impact of the lunar cycle on the incidence of aneurysmal subarachnoid haemorrhages. Methods We retrospectively identified all patients admitted to the department of neurosurgery during 1992 and 2004 suffering from aneurysmal subarachnoid haemorrhage. The onset of bleeding was compared with the lunar phase. Results We did not observe any significant impact of the lunar cycle on the incidence of aneurysmal subarachnoid haemorrhage in 717 consecutive patients ( p = 0.84). Conclusion The impact of the lunar cycle on aneurysmal subarachnoid haemorrhage is a myth rather than reality.

Differences in Aneurysm and Patient Characteristics Between Cohorts of Finnish and Dutch Patients With Subarachnoid Hemorrhage

The high incidence of aneurysmal subarachnoid hemorrhage (aSAH) in Finland may be related to genetic or environmental factors, which may also influence patient and aneurysm characteristics. We compared these characteristics in 2 cohorts in Finland (Kuopio) and the Netherlands (Utrecht). For aSAH patients in Kuopio (n=1786) and Utrecht (n=1788), we compared sex, age at onset, and the sites and number of aneurysms from 1986 to 2005. Five-year time trends were assessed with chi(2) tests (sex distribution and the sites and number of aneurysms) and with 1-way ANOVA (age). The proportion of men in Kuopio (46.1%; 95% CI, 43.8% to 48.4%) was higher than in Utrecht (33.6%, 95% CI, 31.4% to 35.8%) and declined in Kuopio from 50.9% (95% CI, 46.3% to 55.5%) in 1986-1990 to 42.8% (95% CI, 38.0% to 47.6%) in 2001-2005. Mean+/-SD age at onset was 52.4+/-13.3 years in Kuopio and 53.3+/-14.3 years in Utrecht. Both increased similarly over time. The most common aneurysm site in the Kuopio cohort was the middle cerebral artery (33.1%; 95% CI, 30.9% to 35.3%) and in the Utrecht cohort was the anterior communicating artery (38.0%; 95% CI, 35.5% to 40.5%). Multiple aneurysms were more frequent in Kuopio (27.8%; 95% CI, 25.1% to 29.2%) than in Utrecht (14.8%; 95% CI, 13.0% to 16.6%). Sites and proportions of multiple aneurysms did not change during 1986-2005. The cohorts of aSAH patients differed with respect to age at onset and the number and sites of aneurysms. The decline in the proportion of men in Kuopio coincided with increased smoking and alcohol use in women and decreased smoking in men. The differences in aneurysm characteristics remained stable, which suggests that these factors are less influenced by environmental factors.

Impact of the lunar cycle on the incidence of intracranial aneurysm rupture: Myth or reality?

Objective To analyze the impact of the lunar cycle and season on the incidence of aneurysmal subarachnoid hemorrhage (SAH). Patients and methods The medical records of 111 patients who were admitted over a 5-year period to our department because of aneurysmal SAH were retrospectively reviewed. The date of aneurysm rupture was matched with the corresponding season and moon phase. Results An incidence peak for aneurysm rupture (28 patients) was seen during the phase of new moon, which was statistically significant ( p < 0.001). In contrast, no seasonal variation in the incidence of SAH was observed. Conclusion The lunar cycle seems to affect the incidence of intracranial aneurysm rupture, with the new moon being associated with an increased risk of aneurysmal SAH.