Factors Associated with Aneurysm Size in Patients with Subarachnoid Hemorrhage: Effect of Smoking and Aneurysm Location:

Neuroimaging characteristics of ruptured aneurysm as predictors of outcome after aneurysmal subarachnoid hemorrhage: pooled analyses of the SAHIT cohort

OBJECT Neuroimaging characteristics of ruptured aneurysms are important to guide treatment selection, and they have been studied for their value as outcome predictors following aneurysmal subarachnoid hemorrhage (SAH). Despite multiple studies, the prognostic value of aneurysm diameter, location, and extravasated SAH clot on computed tomography scan remains debatable. The authors aimed to more precisely ascertain the relation of these factors to outcome. METHODS The data sets of studies included in the Subarachnoid Hemorrhage International Trialists (SAHIT) repository were analyzed including data on ruptured aneurysm location and diameter (7 studies, n = 9125) and on subarachnoid clot graded on the Fisher scale (8 studies; n = 9452) for the relation to outcome on the Glasgow Outcome Scale (GOS) at 3 months. Prognostic strength was quantified by fitting proportional odds logistic regression models. Univariable odds ratios (ORs) were pooled across studies using random effects models. Multivariable analyses were adjusted for fixed effect of study, age, neurological status on admission, other neuroimaging factors, and treatment modality. The neuroimaging predictors were assessed for their added incremental predictive value measured as partial R(2). RESULTS Spline plots indicated outcomes were worse at extremes of aneurysm size, i.e., less than 4 or greater than 9 mm. In between, aneurysm size had no effect on outcome (OR 1.03, 95% CI 0.98-1.09 for 9 mm vs 4 mm, i.e., 75th vs 25th percentile), except in those who were treated conservatively (OR 1.17, 95% CI 1.02-1.35). Compared with anterior cerebral artery aneurysms, posterior circulation aneurysms tended to result in slightly poorer outcome in patients who underwent endovascular coil embolization (OR 1.13, 95% CI 0.82-1.57) or surgical clipping (OR 1.32, 95% CI 1.10-1.57); the relation was statistically significant only in the latter. Fisher CT subarachnoid clot burden was related to outcome in a gradient manner. Each of the studied predictors accounted for less than 1% of the explained variance in outcome. CONCLUSIONS This study, which is based on the largest cohort of patients so far analyzed, has more precisely determined the prognostic value of the studied neuroimaging factors. Treatment choice has strong influence on the prognostic effect of aneurysm size and location. These findings should guide the development of reliable prognostic models and inform the design and analysis of future prospective studies, including clinical trials.

Risk Factors for Cerebral Vasospasm Following Aneurysmal Subarachnoid Hemorrhage: A Review of the Literature

OBJECTIVE

To examine the literature on risk factors for cerebral vasospasm (CV), one of the most serious complications following aneurysmal subarachnoid hemorrhage (SAH), with special reference to the definition of CV.

METHODS

Using standard search engines, including PubMed, the medical literature on risk factors for CV after SAH was reviewed, and the best definition representative of CV was searched.

RESULTS

Severe SAH evident on computed tomography scan was the only consistent risk factor for CV after SAH. Effects of risk factors on CV, including age, clinical grade, rebleeding, intraventricular or intracerebral hemorrhage on computed tomography scan, acute hydrocephalus, aneurysm site and size, leukocytosis, interleukin-6 level, and cardiac abnormalities, appeared to be associated with the severity of SAH rather than each having a direct effect. Cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram were associated with CV without any relationship to SAH severity. With regard to parameters representative of CV, the grade of angiographic vasospasm (i.e., the degree of arterial narrowing evident on angiography) was the most adequate. Nevertheless, few reports on the risk factors associated with angiographic vasospasm grade have been reported to date.

CONCLUSIONS

Severe SAH evident on computed tomography scan appears to be a definite risk factor for CV after SAH, followed by cigarette smoking, hypertension, and left ventricular hypertrophy on electrocardiogram. To understand the pathogenesis of CV, further studies on the relationships between risk factors, especially factors not related to the severity of SAH, and angiographic vasospasm grade are necessary.

The impact of smoking on neurosurgical outcomes

Cigarette smoking is a common health risk behavior among the general adult population, and is the leading preventable cause of morbidity and mortality in the US. The surgical literature shows that active tobacco smoking is a major risk factor for perioperative morbidity and complications, and that preoperative smoking cessation is an effective measure to lower these risks associated with active smoking. However, few studies have examined the effects of smoking and perioperative complications following neurosurgical procedures. The goal of this review was to highlight the scientific data that do exist regarding the impact of smoking on neurosurgical outcomes, to promote awareness of the need for further work in the specific neurosurgical context, and to suggest ways that neurosurgeons can promote smoking cessation in their patients and lead efforts nationally to emphasize the importance of preoperative smoking cessation. This review indicates that there is limited but good evidence that smoking is associated with higher rates of perioperative complications following neurosurgical intervention. Specific research is needed to understand the effects of smoking and perioperative complications. Neurosurgeons should encourage preoperative smoking cessation as part of their clinical practice to mitigate perioperative morbidity associated with active smoking.

Influence of experimental subarachnoid hemorrhage on nicotine-induced contraction of the rat basilar artery in relation to arachidonic acid metabolites signaling pathway

BACKGROUND

Smoking is one of the most important risk factors for cerebral circulatory disorders. The purpose of this study was to investigate the influence of experimental subarachnoid hemorrhage (SAH) on nicotine-induced contraction (arachidonic acid metabolites) in the basilar arteries of rats.

METHODS

Rats were killed at 1 hour and 1 week after blood injection, and the basilar artery was isolated and cut into a spiral strip.

RESULTS

Testing of cyclooxygenase-1 (COX-1) and 5-lipoxygenase (5-LOX) inhibitors revealed no significant differences in their effects on normal and SAH (1 hour and 1 week). Phospholipase C (PLC) inhibitor (1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17yl)amino)hexyl)-1H-pyrrole-2,5,-dione [U-73122]) slightly inhibited contraction of SAH (1 hour and 1 week) when compared to controls. Phospholipase A2 (PLA2) inhibitor (manoalide) and cytosolic PLA2 (cPLA2) inhibitor (arachidonyltrifluoromenthylketone [AACOCF3]) more strongly attenuated contraction in SAH (1 hour and 1 week) than in controls. Secreted PLA2 (sPLA2) inhibitor (indoxam), PLC inhibitor (2-nitro-4-carboxyphenyl N, N-diphenylcarbamate [NCDC]), and COX-2 inhibitors (nimesulide, (5-methanesulfonamido-6-(2,4-difluorothiophenyl)-1-indanone) [L-745337], and celecoxib) only slightly inhibited contraction of SAH (1 week) when compared to normal and SAH (1 hour). The calcium-independent PLA2 (iPLA2) inhibitor bromoenol lactone (BEL) showed greater inhibition of contraction in SAH (1 hour) when compared to normal and SAH (1 week).

CONCLUSIONS

One week after exposure to SAH, PLC, sPLA2, and COX-2 activity were enhanced and cPLA2 activity was inhibited. One hour after exposure to SAH, PLC activity was enhanced and cPLA2 and iPLA2 activity was inhibited. Such changes of inflammatory arachidonic acid metabolites by smoking after SAH may play important roles in fatal cerebral circulatory disorders, suggesting important implications for the etiology and pathogenesis of SAH.

Cigarette smoking as a risk factor for recurrence of aneurysms treated by endosaccular occlusion

Object

Aneurysms treated by endovascular coil embolization have been associated with coil compaction, and the rate of recanalization has been reported to be as high as 40%. The authors report the first published evidence of a correlation between aneurysm recanalization correlated with a history of cigarette smoking.

Methods

The authors conducted a retrospective chart review of all cases involving patients admitted to their institution from January 1, 2003, to December 31, 2003, for treatment of a cerebral aneurysm. Cases in which patients were treated with coil embolization were reviewed for inclusion. Coil compaction was defined as change in the shape of the coil mass. Aneurysm recanalization was defined as an increase in inflow to the aneurysm in comparison with baseline. The incidence of coil compaction and the relationship with cigarette smoking history were compared in patients with and without recurrence.

Results

A total of 110 patients qualified for inclusion. The odds ratio (OR) for aneurysm recanalization after endosaccular occlusion with respect to history of cigarette smoking was significant for the entire cohort (OR 4.53, 95% confidence interval [CI] 1.95–10.52) and especially for the female cohort (OR 3.72, 95% CI 1.45–9.54). The male cohort demonstrated a trend toward a direct correlation, but the sample size was not large enough for statistical significance (OR 7.50, 95% CI 1.02–55.00).

Conclusions

There was an increased risk of recanalization especially in patients with low-grade subarachnoid hemorrhage who had a history of cigarette smoking. These data suggest a correlation between cigarette smoking and aneurysm recurrence.

Usefulness of MR imaging for the assessment of nonophthalmic paraclinoid aneurysms

BACKGROUND AND PURPOSE

The neuroradiologic location of asymptomatic paraclinoid aneurysms is decisive for patient management. In a preliminary study, we designed a paraclinoid MR protocol (PMP) including high-resolution T2-weighted images in 2 orthogonal planes to define the inferior limit of the distal dural ring plane that represents the borderline between the intradural and extradural internal carotid artery. In this clinical study, we compared this protocol with digital subtraction angiography (DSA) for the location of paraclinoid aneurysms.

MATERIALS AND METHODS

During a 3-year period, we performed PMP and conventional angiograms in 14 consecutive patients with 17 asymptomatic paraclinoid aneurysms. Ophthalmic (superior) aneurysms were excluded. Two independent observers reviewed MR imaging data, and a third experienced neuroradiologist analyzed the conventional angiograms. MR imaging and conventional angiograms were independently analyzed, and interpretations obtained with each technique were compared.

RESULTS

PMP allowed correct visualization of the aneurysms in all patients. No significant differences (P >.05) were found between the DSA and PMP for the measurement of the aneurysmal neck or sac. Interobserver agreement was good. MR imaging was discordant with conventional angiography regarding the position around the cavernous sinus of the aneurysmal neck and sac in 5 cases. PMP images were helpful for treatment decisions in 4 cases.

CONCLUSION

PMP is an interesting tool that might be used in association with conventional angiography for the assessment of paraclinoid aneurysms.

Unruptured intracranial aneurysms: using evidence and outcomes to guide patient teaching

It is estimated that approximately 10 to 15 million Americans have intracranial aneurysms. Intracranial aneurysms are classified as either unruptured or ruptured. Advances in knowledge and technology are enhancing diagnosis, management, and outcomes associated with unruptured intracranial aneurysms. Optimal outcomes are achieved when aneurysms are treated before they rupture. If the aneurysm ruptures, the mortality rate ranges from 30% to 60%. A review of evidence regarding aneurysms, including the pathogenesis, risk factors, treatment options, and outcomes, is presented. Treatment options addressed include surgical clipping, endovascular coiling, or watchful waiting. Current evidence supports aggressive treatment for patients with previously ruptured aneurysms, large or symptomatic aneurysms, a family history of aneurysm rupture, a long life expectancy, and aneurysms demonstrating growth. Factors that favor watchful waiting include aneurysms that are small or located in the anterior circulation and in patients with a short life expectancy or comorbid medical conditions. Nurses are in an ideal position to use evidence and outcomes to provide accurate and current information on how to reduce the risks for rupture and evaluate treatment options.

Risk of hemorrhagic stroke in Asian American ethnic groups

The sparseness of prospective data about hemorrhagic stroke (HS) risk among Asian American ethnic groups led to the investigation of 128,934 persons with self-classified ethnicity at health examinations in 1978-1985. Subsequently, 431 persons were hospitalized for HS; 31% for subarachnoid hemorrhage (SAH) and 69% for intracerebral hemorrhage (ICH). Ethnic predictors of HS were studied by Cox proportional hazard models with 7 covariates. With whites as reference, the adjusted relative risk (95% CI) of all Asians for HS was 1.6 (1.1-2.3, p = 0.01), due substantially to increased risks of SAH in Japanese people and ICH in Filipinos. These data mandate emphasis upon preventive measures in these groups.

Risk factors for aneurysmal subarachnoid hemorrhage in patients in Izumo City, Japan

OBJECT

The annual incidence of aneurysmal subarachnoid hemorrhage (SAH) in Izumo City, Japan, appears to be the highest rate among those reported; therefore the author investigated the risk factors for SAH in patients in this city.

METHODS

A case-control study of 247 patients (108 men and 139 women with ages ranging from 28-96 years) with aneurysmal SAH was conducted in Izumo between 1980 and 1998. Hypertension, diabetes mellitus, heart disease, liver disease, cigarette smoking, alcohol consumption, and serum levels of total cholesterol, aspartate aminotransferase, alanine aminotransferase, and urea nitrogen were assessed as possible risk factors for SAH by using conditional logistic regression. After adjustment for other risk factors, results of multivariate analysis showed that hypertension was the most powerful risk factor, regardless of age and sex. The odds ratio for hypertension was higher in women than in men. The second greatest risk factors were cigarette smoking in those 59 years of age or younger and in men and hypercholesterolemia in those 60 years of age or older and in women. Among individuals 60 years of age or older and among women, diabetes mellitus and heart disease were inversely associated with the risk of SAH. When analyses were performed in 219 cases of confirmed ruptured cerebral aneurysm, very similar results were obtained.

CONCLUSIONS

Among patients in Izumo, hypertension was the most notable risk factor for aneurysmal SAH, regardlessof age and sex, followed by cigarette smoking in younger men and hypercholesterolemia in older women. In older women, diabetes mellitus and heart disease decreased the risk of SAH.

Size of cerebral aneurysms and related factors in patients with subarachnoid hemorrhage

BACKGROUND

As the indication for surgical treatment of incidentally discovered small aneurysms remains controversial.

METHODS

We retrospectively investigated the characteristics of small ruptured aneurysms and examined the relationship between the size and location of ruptured intracranial aneurysms and the sex, age, lifestyle, and medical history of 280 patients with ruptured aneurysm treated at our institute.

RESULTS

The mean diameter of ruptured aneurysms in this series was 7.6 mm. In diameter, 135 (48.2%) ranged between 5 and 10 mm; 73 (26.1%) were smaller than 5 mm. The size of the ruptured aneurysms was significantly smaller (mean 6.5 mm) in patients with non- or poorly controlled hypertension than in normotensive patients (mean 8.3 mm) (p < 0.05). Ruptured aneurysms in the anterior communicating artery (AcomA) and anterior cerebral artery (ACA) were significantly smaller (p < 0.01) than those in the internal carotid artery or middle cerebral artery. Among 58 patients with multiple aneurysms, only 7 (12%) suffered rupture of aneurysms smaller than 5 mm (p < 0.01). Patients younger than 40 years and patients with a family history of subarachnoid hemorrhage appeared to predispose to the rupture of small-sized aneurysms, although those did not affect the statistical significance.

CONCLUSIONS

This study shows that even aneurysms smaller than 10 mm may rupture. However, treatment decisions for unruptured aneurysm should not be based solely on the size of the unruptured aneurysms. Our data implies that even small aneurysms in the AcomA and ACA had an increased tendency for rupture, and that hypertensive patients were at higher risk for the rupture of small aneurysms.

Identifying patients at risk for postprocedural morbidity after treatment of incidental intracranial aneurysms: the role of aneurysm size and location

Object

A decision to treat incidental intracranial aneurysms (IIAs) relies on understanding the risks of treatment and weighing them against the those of aneurysm rupture. Whereas the natural history of IIAs is currently being studied, the risks associated with treating IIAs and factors associated with poor outcome need to be clearly established.

Methods

In a consecutive series of 125 patients, 160 IIAs were treated either surgically (152 cases) or endovascularly (eight cases). Postprocedural morbidity was defined as a new neurological deficit associated with a score greater than or equal to 3 on the modified Rankin Scale or a score of less than 24 on the Mini-Mental Status Examination. Logistic regression analysis was used to identify predictors of postprocedural morbidity from retrospectively collected data on demographic, clinical, and radiographic characteristics.

Treatment of IIAs was not associated with any mortality and was associated with postprocedural morbidity in 17 (13.6%) of 125 patients (early outcome) and eight (6.4%) of patients (late outcome). In the logistic-regression model, treatment of aneurysms (≥13 mm) and posterior circulation aneurysms were independently associated with postprocedural morbidity. In patients in whom postprocedural neurological deficits developed, 12 (70.6%) of 17 and four (23.5%) of 17 patients harbored aneurysms with broad or calcified necks, respectively. Age, comorbidities, multiple aneurysms, specific aneurysm location, and history of subarachnoid hemorrhage related to a different aneurysm were not significantly associated with poor outcome.

Conclusions

The authors found that IIAs can be safely and effectively treated without causing mortality and with a lower morbidity rate than previously reported. A combination of radiographic variables may be helpful in identifying patients at risk for postprocedural morbidity.

Seasonal variation in the incidence of aneurysmal subarachnoid hemorrhage in hospital- and community-based studies

OBJECT

The aim of this study was to examine seasonal variations in the onset of aneurysmal subarachnoid hemorrhage (SAH) in one hospital-based and one community-based patient series.

METHODS

The study population consisted of 941 patients with aneurysmal SAH who were admitted to Shimane Prefectural Central Hospital and 358 patients who were treated in Izumo City, Japan. When investigated as a whole, no significant seasonal variations were found in either population; however, in both series, statistically significant seasonal trends, with a peak in winter and a nadir in summer, were found among patients aged 59 years or younger (p < 0.05 for the hospital-based series and p < 0.005 for the community-based series), but not among those aged 60 years or older, regardless of sex. In the hospital-based series, seasonal variations were most apparent at certain times of day, with significant variations observed between 8:00 a.m. and 10:00 a.m. or 8:00 a.m. and noon (p < 0.001 and p < 0.005, respectively), regardless of patient age, and between 4:00 p.m. and 6:00 p.m. for patients aged 59 years or younger (p < 0.05). Consequently, seasonal variations were significant during daytime hours (between 8:00 a.m. and 8:00 p.m., p < 0.005) but not during the night (between 8:00 p.m. and 8:00 a.m.). Similar tendencies were found in the community-based series. Among patients aged 59 years or younger who had no risk factors for SAH, these seasonal variations were significant in both series. In patients with untreated hypertension, who were current smokers and daily alcohol drinkers, however, no significant patterns were observed in either series, even among younger patients.

CONCLUSIONS

In both hospital- and community-based studies, aneurysmal SAH appears to undergo seasonal variation, with a peak in winter and a nadir in summer. This seasonal pattern may be derived mainly from the occurrence of SAH in the morning, but may also be modified by patient age and SAH risk factors, resulting in the masking of significant seasonal patterns when all patients are considered together.

Endovascular treatment of intracranial aneurysms by using Guglielmi detachable coils in awake patients: safety and feasibility

OBJECT

Embolization of intracranial aneurysms performed using Guglielmi detachable coils (GDCs) is performed with the patient in a state of general anesthesia at most centers. Such an approach does not allow intraprocedural evaluation of the patient's neurological status and carries additional risks associated with general anesthesia and mechanical ventilation. At the authors' institution, GDC embolization of intracranial aneurysms is performed in awake patients after administration of sedative and analgesic agents (midazolam, fentanyl, morphine, and/or hydromorphone). To determine the feasibility and safety of this approach, the authors have retrospectively reviewed their clinical experience.

METHODS

The authors reviewed the medical records of all patients in whom GDC embolization for the treatment of intracranial aneurysms was undertaken between February 1, 1990 and October 31, 1999. Clinical presentation, medical comorbidities, anesthetic agents used, intraprocedural complications, and final procedural outcome were recorded for each patient. Guglielmi detachable coil embolization was attempted in the awake patient in 150 procedures. Among 92 procedures for unruptured aneurysms, 75 (82%) were completed without complications. Four procedures were completed with complications. Of the 92 procedures, 13 were aborted due to patient uncooperativeness (one patient), complications (three patients), morphological characteristics of the aneurysm or surrounding vessels that made embolization technically difficult (eight patients), or vasospasm (one patient). Among 58 procedures for ruptured aneurysms, the procedure was completed without complication in 48 cases (83%). The procedure was completed with complications in five cases and two patients required induction of general anesthesia during the procedure. Five procedures were aborted because morphological characteristics of the aneurysm or surrounding vessels made embolization technically difficult (two patients) or because of aneurysm rupture (two patients) or the appearance of a transient neurological deficit (one patient).

CONCLUSIONS

Embolization of intracranial aneurysms performed using GDCs in the awake patient appears to be safe and feasible and allows intraprocedural evaluation of the patient. Potential advantages, including decreased cardiopulmonary morbidity rates, shorter hospital stay, and lower hospital costs, still require confirmation by a direct comparison with other anesthetic procedures.

Primary intracerebral and aneurysmal subarachnoid hemorrhage in Izumo City, Japan. Part I: incidence and seasonal and diurnal variations

OBJECT

The purpose of this community-based study was first to estimate the incidence rates of primary intracerebral hemorrhage (ICH) and aneurysmal subarachnoid hemorrhage (SAH) in Izumo City, Japan, and second to investigate whether there were seasonal and diurnal periodicities in their onset.

METHODS

During 1991 through 1996, 267 patients with primary ICH and 123 with aneurysmal SAH were treated in Izumo City. The crude and the age- and sex-adjusted annual incidence rates per 100,000 population for all ages were 52 and 48 for ICH and 24 and 23 for SAH, respectively. These incidence rates were higher than those previously published for any other geographical region. The incidence rates of both ICH and SAH increased almost linearly with age. For ICH, a significant seasonal pattern was observed in men and in patients younger than 65 years, with a peak in winter and a trough in summer. However, no significant seasonal fluctuation was found in women or in individuals aged 65 years or older. There was no significant seasonal periodicity for SAH, even when patients were analyzed according to sex and age. Diurnal variations in the onset of both ICH and SAH were significant (except in men with SAH), with a nadir between midnight and 6:00 a.m.

CONCLUSIONS

The actual incidence rates of both primary ICH and aneurysmal SAH seem to be much higher than have been reported so far. In addition, the data indicate the existence of seasonal periodicity for men and younger patients with ICH, and that the risk of both ICH and SAH is lower during nighttime.