Intracranial aneurysms. Age, sex, blood pressure, and multiplicity in an unselected series of patients

Chronological Change of the Clinical Features and Treatment Outcomes for Subarachnoid Hemorrhage in Japan: A Multicenter Retrospective Study

Aneurysmal subarachnoid hemorrhage (SAH) treatment has progressed, and patients are rapidly aging in Japan. Consequently, dynamic changes must have emerged in the clinical practice of SAH. This study aimed to elucidate chronological changes of aneurysmal SAH and the prognostic factors in the previous quarter century in Japan. We conducted a retrospective survey regarding aneurysmal SAH in eight institutions in Japan. The study included 848, 863, and 781 patients in the first (1989-1993), second (1999-2003), and third (2009-2013) periods, respectively. The chronological changes of factors that influenced the poor outcomes and differences between the nonelderly (<75 years) and elderly patients were investigated. Mean age was significantly higher in patients in the third period (61.4 years) than in those in the other two periods (first, 57.8 years; second, 59.5 years). During these periods, the proportion of good outcomes did not change; however, the mortality rate significantly decreased from 19% in the first period to 11% and 9.2% in the second and third periods, respectively. The poor outcome was mainly caused by the significantly higher incidence of systemic complication and procedural complication in the first period and the significantly lower incidence of delayed ischemic neurological deficit in the third period. The elderly patients had significantly poorer clinical outcomes than the nonelderly ones. During the last 25 years, the age of patients with aneurysmal SAH has rapidly increased. The study results may contribute to the improvement of the treatment strategy of SAH in advanced countries with a rapidly aging population.

HYBRID MICROSURGICAL AND ENDOVASCULAR APPROACH IN THE TREATMENT OF MULTIPLE CEREBRAL ANEURYSMS: AN ILLUSTRATIVE CASE SERIES IN CORRELATION WITH LITERATURE DATA

Contemporary cerebral aneurysm treatment has advanced due to the expansion of microsurgical and endovascular techniques having different advantages and restraints. However, some aneurysms cannot be effectively treated by a single method alone due to their specific anatomy, location, complexity, and/or multiplicity. Subsequently, multiple aneurysms sometimes necessitate a hybrid strategy integrating both methods. The study aims were to discuss indications, possibilities, and challenges of a hybrid strategy in the decision making and treatment of multiple intracranial aneurysms. A single-institution illustrative case series of multiple intracranial aneurysm patients treated by a hybrid approach was analyzed and management outcome discussed and correlated with literature data. Following the treatment, both patients from our case series recovered well, having complete and stable aneurysmal occlusion with no relapse and no postoperative procedure-related complications or long-lasting neurological symptoms. In conclusion, a hybrid approach is advised as a treatment option for multiple cerebral aneurysms when a single modality is insufficient to bring satisfactory results. It may be a suitable and safe addition to an assortment of treatments pledging clinical improvement and enabling positive management outcome in patients with ruptured and non-ruptured multiple cerebral aneurysms.

Risk factors involved in the formation of multiple intracranial aneurysms

BACKGROUND

Although several risk factors of the multiple intracranial aneurysms (MIAs) formation has been reported, the results are controversial. We aimed to find out the risk factors of MIAs formation by analyzing our clinic data combined with a meta-analysis.

MATERIAL AND METHODS

A retrospective review work of medical records for the patients with aneurysms was undertaken. Univariate analysis was used to examine all mentioned variables. Binary logistic regression analysis was used to identify the risk factors of MIAs formation.

RESULTS

In the retrospective review work, a total of 565 patients with aneurysm were included in this study. Of these 565 participants, 449 patients suffered SIAs and 116 patients suffered MIAs. Univariate analysis showed a significant difference in terms of female, cigarette smoking, family history of hypertension, and primary hypertension between the SIAs and MIAs group. The binary logistic regression analysis showed that the female (OR = 1.624), primary hypertension (OR = 1.563), and family history of hypertension (OR = 2.496) were independent risk factors of the formation of MIAs (for each P < 0.05). With regard to the meta-analysis results, it revealed that there was significant difference in the rates of female (P < 0.001), cigarette smoking (P < 0.001), primary hypertension (P = 0.001), and higher age (P = 0.011) among the MIAs patients.

CONCLUSIONS

A higher rate of the formation of MIAs is closely associated with the elder and female. Patients with hypertension history, cigarette smoking, and family primary hypertension history also affected the formation of MIAs, these risk factors should be a guard against.

Cerebral Aneurysms and Polycystic Kidney Disease: A Critical Review

The pathogenic basis of the association between adult polycystic kidney disease (APKD) and cerebral aneurysms is unknown. We have compared cerebral aneurysms in 79 patients with APKD gleaned from the literature to the sporadic aneurysm cases reported by the Cooperative Study to determine if there are significant biological differences between these two groups. Sixty-eight patients had a single aneurysm and 11 (14%) had multiple aneurysms. In APKD patients with subarachnoid hemorrhage from a single aneurysm there was a significant over-representation of males (72%, p < 0.01); and the APKD group had more aneurysms of the middle cerebral artery (37%, p < 0.05). The peak decennial incidence and mean age of rupture of APKD-associated aneurysms was younger (mean age 39.7 years, p < 0.01) and over 77% of APKD-associated aneurysms had ruptured by age 50 versus 42% for sporadic aneurysms (p < 0.001). Cerebral aneurysms co-existed with APKD in the absence of hypertension in 25% of 45 cases where the presence or absence of hypertension was recorded. These biological differences and the occurrence of aneurysms in normotensive APKD patients suggests an etiology which may be independent of hypertension and that APKD-associated aneurysms may be genetically determined. It is hypothesized that cases of inherited, familial cerebral aneurysms could be linked to a genetic defect resembling that which occurs on chromosome 16 in APKD.

Pressure Changes Within the Sac of Human Cerebral Aneurysms in Response to Artificially Induced Transient Increases in Systemic Blood Pressure

Formation and rupture of cerebral aneurysms have been associated with chronic hypertension. The effect of transient increase in blood pressure and its effect on intra-aneurysmal hemodynamics have not been studied. We examined the effects of controlled increases in blood pressure on different pressure parameters inside the sac of human cerebral aneurysms and corresponding parent arteries using invasive technology. Twelve patients (10 female, 2 male, age 54±15 years) with unruptured cerebral aneurysms undergoing endovascular coiling were recruited. Dual-sensor microwires with the capacity to simultaneously measure flow velocity and pressure were used to measure systolic, diastolic, and mean pressure inside the aneurysm sac and to measure both pressures and flow velocities in the feeder vessel just outside the aneurysm. These pressures were recorded simultaneously with pressures from a radial arterial catheter. Measurements were taken at baseline and then during a gradual increase in systemic systolic blood pressure to a target value of ≈25 mm Hg above baseline, using a phenylephrine infusion. The dose needed to achieve the required increase in radial arterial systolic blood pressure was 0.8±0.2 μg/kg/min. There was a clear linear relationship between changes in radial and aneurysmal pressures with substantial patient-by-patient variation in the slopes of those relationships. The overall increases in systolic and mean pressures in both radial artery and in the aneurysms were similar. Pressures in the aneurysm and in the parent vessels were similar. Peak and mean flow velocities in the parent arteries did not change significantly with phenylephrine infusion, nor did vessel diameters as measured angiographically.

A comparative review of the hemodynamics and pathogenesis of cerebral and abdominal aortic aneurysms: lessons to learn from each other

OBJECTIVE

Cerebral aneurysms (CAs) and abdominal aortic aneurysms (AAAs) are degenerative vascular pathologies that manifest as abnormal dilations of the arterial wall. They arise with different morphologies in different types of blood vessels under different hemodynamic conditions. Although treated as different pathologies, we examine common pathways in their hemodynamic pathogenesis in order to elucidate mechanisms of formation.

MATERIALS AND METHODS

A systematic review of the literature was performed. Current concepts on pathogenesis and hemodynamics were collected and compared.

RESULTS

CAs arise as saccular dilations on the cerebral arteries of the circle of Willis under high blood flow, high wall shear stress (WSS), and high wall shear stress gradient (WSSG) conditions. AAAs arise as fusiform dilations on the infrarenal aorta under low blood flow, low, oscillating WSS, and high WSSG conditions. While at opposite ends of the WSS spectrum, they share high WSSG, a critical factor in arterial remodeling. This alone may not be enough to initiate aneurysm formation, but may ignite a cascade of downstream events that leads to aneurysm development. Despite differences in morphology and the structure, CAs and AAAs share many histopathological and biomechanical characteristics. Endothelial cell damage, loss of elastin, and smooth muscle cell loss are universal findings in CAs and AAAs. Increased matrix metalloproteinases and other proteinases, reactive oxygen species, and inflammation also contribute to the pathogenesis of both aneurysms.

CONCLUSION

Our review revealed similar pathways in seemingly different pathologies. We also highlight the need for cross-disciplinary studies to aid in finding similarities between pathologies.

Gender-related protection from or vulnerability to severe CNS diseases: gonado-structural and/or gonado-activational? A meta-analysis of relevant epidemiological studies

BACKGROUND

A vast scientific literature has dealt with gender-specific risk for brain disorder. That field is evolving toward a consensus to the effect that the estrogen hormone family is outstandingly and uniquely neuroprotective. However, the epidemiology relevant to this general outlook remains piecemeal.

METHOD

The present investigation strategically formats the relevant epidemiological findings around the world in order to quantitatively meta-analyze gender ratio of risk for a variety of relevant severe central nervous system (CNS) diseases at all three gonadal stages of the life cycle, pre pubertal, post adolescent/pre menopausal, and post menopausal.

RESULTS

The data quantitatively establish that (1) no single epidemiological study should be cited as evidence of gender-specific neuroprotection against the most common severe CNS diseases because the gender-specific risk ratios are contradictory from one study to the other; (2) risk for severe CNS disease is indeed significantly gender-specific, but either gender can be protected: it depends on the disease, not at all on the age bracket.

CONCLUSION

Our assay of gender-specific risk for severe brain disease around the world has not been able to support the idea according to which any one gender-prevalent gonadal steroid hormone dominates as a neuroprotective agent at natural concentrations.

Risk of hemorrhage from de novo cerebral aneurysms

OBJECT

A small percentage of patients will develop a completely new or de novo aneurysm after discovery of an initial aneurysm. The natural history of these lesions is unknown. The authors undertook this statistical evaluation a large cohort of patients with both ruptured and unruptured de novo aneurysms with the aim of analyzing risk factors for rupture and estimating a risk of subarachnoid hemorrhage (SAH).

METHODS

A review of a prospectively maintained database of all aneurysm patients treated by the vascular neurosurgery service of Goodman Campbell Brain and Spine from 1976-2010 was performed. Of the 4718 patients, 611 (13%) had long-term follow-up imaging. The authors identified 27 patients (4.4%) with a total of 32 unruptured de novo aneurysms from routine surveillance imaging. They identified another 10 patients who presented with a new SAH from a de novo aneurysm after treatment of their original aneurysm. The total study group was thus 37 patients with a total of 42 de novo aneurysms. The authors then compared the 27 patients with incidentally discovered aneurysms with the 10 patients with SAH. A statistical analysis was performed, comparing the 2 groups with respect to patient and aneurysm characteristics and risk factors.

RESULTS

Thirty-seven patients were identified as having true de novo aneurysms. This group had a female predominance and a high percentage of smokers. These 37 patients had a total of 42 de novo aneurysms. Ten of these 42 aneurysms hemorrhaged. De novo aneurysms in both the SAH and non-SAH group were anatomically small (< 10 mm). The estimated risk of hemorrhage over 5 years was 14.5%, higher than the expected SAH risk of small, unruptured aneurysms reported in the ISUIA (International Study of Unruptured Intracranial Aneurysms) trial. There was no statistically significant correlation between hemorrhage and any of the following risk factors: hypertension, diabetes, tobacco and alcohol use, polycystic kidney disease, or previous SAH. There was a statistically significant between-groups difference with respect to patient age, with the mean patient age being significantly older in the SAH aneurysm group than in the non-SAH group (p = 0.047). This is likely reflective of longer follow-up and discovery time, as the mean length of time between initial treatment and discovery of the de novo aneurysm was longer in the SAH group (p = 0.011).

CONCLUSIONS

While rare, de novo aneurysms may have a risk for SAH that is comparatively higher than the risk associated with similarly sized, small, initially discovered unruptured saccular aneurysms. The authors therefore recommend long-term follow-up for all patients with aneurysms, and they consider a more aggressive treatment strategy for de novo aneurysms than for incidentally discovered initial aneurysms.

Giant intracranial aneurysms: morphology and clinical presentation

The purpose of this study was to correlate the morphology of giant intracranial aneurysms (GIA) with their clinical presentation. Eighty patients with GIA, 14 males and 66 females, were studied. Univariate and multivariate analyses were made to test the associations between morphological and clinical features. The main locations of the unruptured GIA included the carotid cavernous segment, and for the ruptured GIA, the most frequent were the carotid supraclinoid and middle cerebral arteries. There was a significant association among communicating arteries (CA) of "bad" quality and presence of thrombus and calcification (TC). The risk of rupture is 8 times higher in patients with CA of "bad" quality and 11 times higher in patients without TC. GIA are more frequent in the cavernous segment. There is a high rupture risk in the middle cerebral artery. CA of "bad" quality are associated with TC. The rupture risk is significantly higher in patients without TC.

Morphological differences between the aneurysmal and normal artery in patients with internal carotid-posterior communicating artery aneurysm

The aim of this study was to identify image-based morphological parameters that correlated with the formation of internal carotid artery-posterior communicating artery (ICA-PcomA) aneurysms. Morphological parameters obtained from 3-dimensional digital subtraction angiography (3D-DSA) were evaluated from nine patients with ICA-PcomA aneurysms, including the diameter of the ICA (Dica) and PcomA (Dpcom), the angle between the ICA and the origin of the PcomA (Apcom), and the angle between the ophthalmic and communicating segments of the ICA (Aica). Measurements were performed on both sides of each patient. Parameters were analyzed with a paired-samples t-test for significance. In additional, receiver operating characteristic (ROC) analysis was performed on the significant parameter. Statistically significant differences were found between the aneurysmal (45.28±29.07°) and control sides (79.22±17.83°) for Apcom (p=0.020). In the ROC analysis, the area under the curve value of Apcom was 0.852, and the threshold for optimal sensitivity and specificity was 52.25°. Therefore, the Apcom parameter was correlated with the formation of an ICA-PcomA aneurysm, and seems to be a promising morphological parameter for risk assessment of aneurysm formation.

Presence of anatomical variations of the circle of Willis in patients undergoing surgical treatment for ruptured intracranial aneurysms

BACKGROUND/AIM

The presence of aneurysmal changes on the brain blood vessels has been subject to numerous research. This study investigated the relation between ruptured aneurysms and anatomical configuration of the Circle of Willis, with the purpose to obtain an insight into their mutual connection.

METHODS

The analysis included 114 patients suffering from ruptured intracranial aneurysms. Preoperative cerebral angiography was performed and compared with the intraoperative findings in order to attain a precise insight into morphological changes occurring on the circle of Willis.

RESULTS

The prevalence of asymmetrical Willis in the whole group of patients was 64%. Within the group of patients suffering from multiple aneurysms, the presence of asymmetrical Willis' circle was 75.7%. The highest incidence of the asymmetrical Circle of Willis was found among patients with aneurysmal rupture detected at the anterior comunicative artery (ACoA) site (72.7% among cases with solitary and 100% among those with multiple aneurysms). Morphological changes on the A1 segment of ACoA were observed in 50 (44%) cases, with higher incidence found on the right side (60%). When comparing location of ruptured aneurysms between genders, a statistically significant prevalence of the ruptured aneurisms on ACoA was present in men, whereas women showed higher incidence of ruptured aneurysms on interior cartid artery (ICA) site (p < 0.01). The linkage between aneurysms with hypoplasia of the A1 segment of ACA and decreasing of the angle at which segments A1 and A2 join suggests the relationship between their onset, corresponding configuration type of Willis and subsequent hemodynamic changes.

CONCLUSION

High incidence of asymmetry of Willis circle in the group of patients with ruptured aneurysms imply association of asymmetrical configuration and disorder in haemodynamic relations with forming and rupture of intracranial aneurysms.

Incidence and risk factors for multiple intracranial saccular aneurysms in patients with subarachnoid hemorrhage in Izumo City, Japan

BACKGROUND

A community-based study was conducted to estimate the incidence rates of multiple aneurysms and to investigate the factors related to multiplicity.

METHOD

The subjects were 291 patients with ruptured saccular aneurysms treated between 1980 and 1998, in Izumo, Japan. There were 403 aneurysms in total, and 78 patients (27%) had multiple aneurysms.

FINDINGS

Both the crude and the age- and sex-adjusted annual incidence rates per 100,000 population for multiple and single aneurysms were five and 14 for all ages, respectively, and were higher in women than in men. The age-specific incidence rates of both multiple and single aneurysms showed a tendency to increase with age. Of the 190 patients who underwent four-vessel studies, 26% (49) had multiple aneurysms. The frequencies of multiple aneurysms in patients with ruptured aneurysms > or =10 and <10 mm in diameter were 41% and 21%, respectively (p = 0.0081). In patients with multiple aneurysms, the number of aneurysms was greater in those with large ruptured aneurysms, and the unruptured aneurysms tended to be larger in patients with large ruptured aneurysms. The size of the ruptured aneurysms was positively associated with multiplicity, whereas hypertension had an inverse association. Age, sex, aneurysm site and risk factors other than hypertension were not predictive.

CONCLUSIONS

This study is the first to provide annual incidence rates for multiple aneurysms in a defined population. It appears that multiplicity of aneurysms is associated with larger ruptured aneurysms and that patients with larger ruptured aneurysms have a higher number of aneurysms as well as larger unruptured aneurysms.

Risk factors for the formation and rupture of intracranial saccular aneurysms in Shimane, Japan

BACKGROUND

Prevention of aneurysmal subarachnoid hemorrhage (SAH) can be achieved by reducing risk factors, which include those for aneurysm formation and aneurysm rupture. However, neither of these 2 factors has been discussed separately so far. A case control study was undertaken in Shimane, Japan, to identify modifiable risk factors for the formation and rupture of aneurysms.

METHODS

This study included 858 patients with ruptured aneurysms, 285 patients with unruptured aneurysms without a history of SAH, and 798 control subjects. Hypertension, diabetes mellitus, heart disease, hypercholesterolemia, cigarette smoking, and alcohol consumption were assessed as risk factors by using conditional logistic regression.

RESULTS

After adjustment for other risk factors, hypertension was the most powerful risk factor for aneurysm formation, regardless of age and sex, followed by hypercholesterolemia, heart disease, and cigarette smoking, whereas diabetes mellitus and daily drinking were insignificant for aneurysm formation. Hypertension and daily drinking were not related to the risk of aneurysm rupture, regardless of age and sex, whereas cigarette smoking was associated with an increased risk of aneurysm rupture in patients 60 years or older and in men. In contrast, hypercholesterolemia was strongly associated with a decreased risk of rupture, regardless of age and sex, and in patients with small aneurysms (<5 mm). Diabetes mellitus and heart disease were also related to a decreased risk of rupture in patients 60 years or older and in women.

CONCLUSION

Identification of risk factors for aneurysm formation and rupture separately seems to be pivotal for reducing the incidence of SAH.

MORPHOLOGICAL DIFFERENCES BETWEEN RUPTURED AND UNRUPTURED CASES IN MIDDLE CEREBRAL ARTERY ANEURYSMS

OBJECTIVE

To elucidate the morphological differences between ruptured and unruptured aneurysms, three-dimensional digital subtraction angiography was performed in 44 cases (20 unruptured, 24 ruptured) of middle cerebral artery aneurysm.

METHODS

When the neck was located on the extension of the midline of the parent artery, it was defined as Type C; when it was not, it was defined as Type D. Aspect ratio (AP ratio; dome/neck ratio) and daughter artery ratio (DA ratio; diameter of the larger daughter artery/diameter of the smaller daughter artery) were calculated, and these ratios were compared for ruptured and unruptured cases.

RESULTS

Nineteen cases were Type C and 25 cases were Type D. χ2 test revealed that there were significantly more ruptured cases among Type C (14 out of 19) compared with Type D (10 out of 25) (P &lt; 0.05). AP ratios were 2.24 ± 0.75 for ruptured cases and 1.56 ± 0.58 for unruptured cases. DA ratios were 1.53 ± 0.54 in ruptured cases and 2.14 ± 0.80 for unruptured cases. Both showed significant differences (P &lt; 0.01). In cases with an AP ratio of 1.8 or greater and a DA ratio less than 1.7, 13 out of 15 (87%) were ruptured cases. On the contrary, in cases with an AP ratio less than 1.8 and a DA ratio of 1.7 or greater, 12 out of 13 (92%) were unruptured cases.

CONCLUSION

Type C and equality of the diameters of two daughter arteries, together with high AP ratios, seem to be morphological factors that associate with aneurysmal rupture.

TNF-alpha-mediated inflammation in cerebral aneurysms: a potential link to growth and rupture

Intracranial aneurysm (IA) rupture is one of the leading causes of stroke in the United States and remains a major health concern today. Most aneurysms are asymptomatic with a minor percentage of rupture annually. Regardless, IA rupture has a devastatingly high mortality rate and does not have specific drugs that stabilize or prevent aneurysm rupture, though other preventive therapeutic options such as clipping and coiling of incidental aneurysms are available to clinicians. The lack of specific drugs to limit aneurysm growth and rupture is, in part, attributed to the limited knowledge on the biology of IA growth and rupture. Though inflammatory macrophages and lymphocytes infiltrate the aneurysm wall, a link between their presence and aneurysm growth with subsequent rupture is not completely understood. Given our published results that demonstrate that the pro-inflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha), is highly expressed in human ruptured aneurysms, we hypothesize that pro-inflammatory cell types are the prime source of TNF-alpha that initiate damage to endothelium, smooth muscle cells (SMC) and internal elastic lamina (IEL). To gain insights into TNF-alpha expression in the aneurysm wall, we have examined the potential regulators of TNF-alpha and report that higher TNF-alpha expression correlates with increased expression of intracellular calcium release channels that regulate intracellular calcium (Ca2+), and Toll like receptors (TLR) that mediate innate immunity. Moreover, the reduction of tissue inhibitor of metalloproteinase-1 (TIMP-1) expression provides insights on why higher matrix metalloproteinase (MMP) activity is noted in ruptured IA. Because TNF-alpha is known to amplify several signaling pathways leading to inflammation, apoptosis and tissue degradation, we will review the potential role of TNF-alpha in IA formation, growth and rupture. Neutralizing TNF-alpha action in the aneurysm wall may have a beneficial effect in preventing aneurysm growth by reducing inflammation and arterial remodeling.

Genetics Of Intracranial Aneurysms

Despite advances in the treatment of intracranial aneurysms (IA) in recent years, the overall outcome of patients with aneurysmal subarachnoid hemorrhage has shown only modest improvement. Given this poor prognosis, diagnosis of IA before rupture is of paramount importance. Currently, there are no reliable methods other than screening imaging studies of high-risk individuals to diagnose asymptomatic patients. Multiple levels of evidence suggest that environmental factors acting in concert with genetic susceptibilities lead to the formation, growth, and rupture of aneurysms in these patients. Epidemiological studies have already identified aneurysm-specific risk factors such as size and location, as well as patient-specific risk factors, such as age, sex, and presence of medical comorbidities, such as hypertension. In addition, exposure to certain environmental factors such as smoking have been shown to be important in the formation of IA. Furthermore, substantial evidence proves that certain loci contribute genetically to IA pathogenesis. Genome-wide linkage studies using relative pairs or rare families that are affected with the Mendelian forms of IA have already shown genetic heterogeneity of IA, suggesting that multiple genes, alone or in combination, are important in the disease pathophysiology. The linkage results, along with association studies, will ultimately lead to the identification of IA susceptibility genes. Identification of the genes important in IA pathogenesis will not only provide novel insights into the primary determinants of IA, but will also result in new opportunities for early diagnosis in the preclinical setting. Ultimately, novel therapeutic strategies based on biology will be developed, which will target these newly elucidated genetic susceptibilities.

Multiple aneurysms of the anterior communicating artery: radiological and surgical difficulties

OBJECT

Multiple aneurysms of the anterior communicating artery (ACoA) occur rarely and have not been well investigated previously. The authors report on a consecutive series of six patients who each harbored multiple ACoA aneurysms. The radiological and surgical difficulties encountered in treating these complex and uncommon aneurysms are described and the pertinent literature is reviewed.

METHODS

Between October 1996 and August 2003, the authors surgically treated 146 patients with ACoA aneurysms. Six (4.1%) of these patients harbored multiple aneurysms of the ACoA. Four of these patients were men and two were women; their ages ranged from 36 to 72 years. Five patients had two aneurysms and one patient had three. All underwent surgery performed using the pterional approach. The clinical presentations, angiograms, intraoperative difficulties, and surgical results were retrospectively analyzed. All patients had premorbid hypertension. In two cases, the aneurysms were initially misdiagnosed as a single complex aneurysm based on routine cerebral angiograms, but special angiographic views demonstrated double aneurysms. In one case, multiple ACoA aneurysms could be identified using three-dimensional (3D) computerized tomography (CT) angiography. The size of the ACoA aneurysms ranged from 3 to 12 mm (mean 5.3 mm). A total of 13 ACoA aneurysms were successfully occluded in the six patients. Four patients were discharged in good condition, and two patients died.

CONCLUSIONS

Although multiple ACoA aneurysms are quite rare, the following points should be kept in mind. (1) In bilobular ACoA aneurysms, special angiographic projections and 3D CT angiography or 3D digital subtraction angiography should also be performed to obtain a correct diagnosis. The differentiation of two aneurysms from a bilobular aneurysm during the preoperative period is important for surgical planning. (2) Angiographically, detection of the ruptured aneurysm is often difficult. (3) Resection of the gyrus rectus is necessary to obtain a good operative exposure. 4) Clip selection and sequencing are important. Straight clips with short blades should be preferred to avoid narrowing of the surgeon's view and a collision between the clips.

Evaluation of relation among aneurysmal neck, parent artery, and daughter arteries in middle cerebral artery aneurysms, by three-dimensional digital subtraction angiography

Intracranial aneurysms usually occur at arterial bifurcations. However, in middle cerebral artery (MCA) aneurysms, we often find that the aneurysmal neck does not necessarily exist just on the arterial bifurcation. In this study, we have evaluated the relation among aneurysmal neck, parent artery, and daughter arteries in middle cerebral artery aneurysms, by three-dimensional digital subtraction angiography. Twenty consecutive patients (9 men and 11 women) with MCA aneurysms were examined. The total number of aneurysms was 22, of which 10 aneurysms were unruptured and 12 were ruptured. Aneurysmal sizes and angles between the parent artery and each of the two daughter arteries were measured. Furthermore, aneurysms were classified into two types based on neck location. Thus, when the neck was located on the extension of the midline of the parent artery, it was defined as a classical neck type aneurysm, and when it was not, it was defined as a deviating neck type aneurysm. There were 15 cases of deviating and 7 cases of classical neck type. Interestingly, in the deviating neck type, all the aneurysms existed on the side of the daughter arteries of which the angles between parent arteries were narrower, and in 93%, the sizes of the daughter arteries in which the neck existed were smaller compared with other daughter arteries.

Estimating the annual rate of de novo multiple aneurysms: three statistical approaches

Object

Individuals with unruptured intracranial aneurysms experience a higher rate of rupture if their history includes another aneurysm that has previously bled. The authors used systematic review and metaregression to estimate the annual rate of development of second de novo aneurysms after subarachnoid hemorrhage.

Methods

This investigation included studies in which more than 300 patients with intracranial aneurysms were described, and in which the age of the patients and the proportion with multiple aneurysms were documented. Studies describing delayed follow-up angiography that was performed after treatment of aneurysms were also reviewed.

Twenty studies were included in a between-study analysis. The univariate odds ratio (OR) for multiple intracranial aneurysms per year of age was 1.085 (95% confidence interval [CI] 1.015–1.165); this value was calculated using a hierarchical model for between-study heterogeneity. Five studies were included that provided age stratification. The estimated OR for multiple intracranial aneurysms per year was 1.011 (95% CI 1.005–1.018). Four follow-up studies were available.

Conclusions

According to the three different approaches (study-level, patient-level, and follow-up analyses), the estimated annual rates of development of de novo aneurysms were 1.62% (95% CI 0.28–3.59%), 0.28% (95% CI 0.12–0.49%), and 0.92% (95% CI 0.64–1.25%), respectively. The estimated annual rate of development of second de novo aneurysms ranged from 0.28 to 1.62%.

A comparison of risk factors in the etiology of mirror and nonmirror multiple intracranial aneurysms

BACKGROUND

Pure mirror intracranial aneurysms represent a subgroup of multiple aneurysm patients where a congenital predisposition may play a major etiologic role. The aim of this study was to compare the pattern of prevalence of known risk factors for aneurysm disease between pure mirror and pure nonmirror multiple aneurysm populations.

METHODS

Clinical records of all patients with multiple intracranial aneurysms admitted to our institution between January 1985 and September 2001 were reviewed. Age, localization of aneurysms, gender, and history of cigarette smoking or hypertension were noted and compared using Fisher's exact test and logistic regression analysis.

RESULTS

There were 33 patients presented with pure mirror aneurysms (MirAn) and 49 with nonmirror multiple aneurysms (nMirAn). Average age of rupture occurred in the 5th decade in both groups. Female:male ratio was 3.1:1 in MirAn; 2.1:1 in nMirAn. In MirAn patients younger than 40 years it was 1:1. Smoking was the most prevalent risk factor in nMirAn (59.2%). In MirAn this was true only for patients in the 5th or 6th decades (65%), and hypertension was the most prevalent risk factor over that age (62.5%). A total of 80% of mirror aneurysm patients under 40 years had no known extrinsic risk factor, compared with 20% in nMirAn (p < 0.05).

CONCLUSIONS

Differences in the relative prevalence of risk factors between both groups supports the hypothesis of a different etiologic process occurring in mirror aneurysm disease. Early rupture in patients with no extrinsic risk factors lends support to the role of a congenital predisposition over degenerative causes in these patients.

Management of intracranial aneurysms: factors that influence clinical grade and surgical outcome

BACKGROUND

We report the experience in managing intracranial aneurysms at our medical center.

METHODS

We retrospectively analyzed 297 intracranial aneurysms managed during a 6-year period. Risk factors were analyzed with respect to their influence on outcome after surgery as measured by Glasgow Outcome Scale score.

RESULTS

Fifty-eight patients had multiple aneurysms. Of all aneurysms, 83% were in the anterior circulation, 37% were unruptured, and 59% were larger than 10 mm in size. Good outcomewas achieved in 75% of patients, and another 16% had fair outcomes. The mortality rate was 4%, and significant morbidity occurred in 5% of patients. Significant indicators of poor outcome were worsened clinical grade, posterior aneurysm location, and large aneurysm size.

CONCLUSION

Hypertensive patients, older patients, and patients with posterior circulation aneurysms had poorer neurologic status, which significantly influenced outcome. Larger aneurysms and vertebrobasilar aneurysms were associated with poor outcomes.

Aneurysmal subarachnoid hemorrhage in young adults

OBJECT

The authors reviewed the management protocols for young adults who presented with subarachnoid hemorrhage (SAH) at the Regional Neurosurgery Unit in Newcastle during a study period of 9 years. Aneurysmal SAH is uncommon in the age group selected (18-39 years) and, therefore, the performance of these patients has not been extensively reported in the literature. The authors also evaluated the good-grade rebleed rate (an index of management efficiency) in this cohort of patients.

METHODS

The Newcastle neurosurgical unit serves a population of close to 3 million people, and an average of 180 patients with SAH are seen each year. The majority of patients are transferred from other hospitals in the region. This study includes patients admitted between January 1990 and December 1998. A total of 1,609 patients were admitted during this period, of whom 295 (18.4%) between the ages of 18 and 39 years constituted the study population of young adults. Two hundred ninety-five young adults presented with SAH; 181 (61.4%) were women and 114 (38.6%) were men, a ratio of 3:2. Of 246 patients in whom this value was recorded, 15 (6.1%) presented with a history of hypertension, and there was an association between hypertension and the occurrence of multiple aneurysms (Fisher two-tailed exact test, p = 0.008). Thirty-five patients (11.9%) presented with a hematoma on computerized tomography scans; of these, 20 (57%) were women and 15 were men. In six patients the lesion had rebled before treatment. The good-grade rebleed rate was three (1.7%) of 178. The overall favorable outcome rate was 83.8% (Glasgow Outcome Scale [GOS] 4 and 5) and unfavorable outcome occurred in 16.2% (GOS 1-3), with a total of 40 deaths in this group (13%). Age had no influence on outcome in young adults. Comparing the outcome at discharge with the follow-up evaluation at 6 months revealed that patients in the moderate and severe disability groups continued to improve and many achieved good recovery.

CONCLUSIONS

In this report the authors detail the outcome of a large number of young adults with SAH. The incidence of SAH was higher in the female population, although the ratio was not as high as previously reported. The authors have also demonstrated a progressive increase in the incidence of aneurysmal SAH with age, even in young adults. Hypertension but not age influenced the occurrence of multiple aneurysms. The good-grade rebleed rate is low, although it is not zero. Generally, a satisfactory outcome was obtained and significant continuing improvements were noted between discharge and follow-up evaluation. This reflects the power of recovery in young adults. These are people whose economic productivity and fertility are at peak levels and therefore the financial and social burden occasioned by less-than-perfect outcomes is large.

Prevalence of intracranial aneurysms in first-degree relatives of patients with aneurysms

Object

A familial predisposition toward cerebral aneurysms has been previously described in patients with two or more affected family members. In the present study the familial incidence of unruptured intracranial aneurysms was studied in 96 patients with at least one first-degree relative (parent, sibling, or child) in whom a cerebral aneurysm was diagnosed.

Methods

All patients were between 20 and 70 years of age and underwent three-dimensional fast–spin echo magnetic resonance imaging. Sixty-one patients (63.5%) were women. The majority of patients (84%) were caucasian and the remainder were Hispanic (13%) or African-American (3%). No patient suffered a medical condition (excluding hypertension and smoking) known to be associated with cerebral aneurysm formation.

In four patients at least one aneurysm was found (two harbored multiple aneurysms). Three of the four patients were women. Two of the patients were siblings. The estimated prevalence in first-degree relatives was 4.2% (95% confidence interval 1.2–10.1). Of note, the mean age in the current study population was 39 years. The authors of recent metaanalyses have suggested that the prevalence of nonfamilial aneurysms is approximately 2%, despite earlier reports in which higher figures were cited.

Conclusions

The authors conclude that first-degree relatives of patients with aneurysms are at higher risk for harboring an intracranial aneurysm.

Vascular anomalies and the risk of multiple aneurysms development and bleeding

SUMMARY

The pathogenesis of aneurysmal subarachnoid hemorrhage is still debated and the prognosis remains severe, especially in multiple aneurysms, where the therapeutic management is complex. The aim of this study was to look for vascular anomalies and assess their relationship with aneurysm formation and bleeding in patients with multiple intracranial aneurysms. A prospective angiographical review was performed on 141 patients with multiple intracranial aneurysms seen from 1992 to 2000. Three hundred and fifty three aneurysms were studied. In 88% of the patients vascular anomalies were found. The most common were: asymmetric caudal basilar fusion (43.2%), variations of the anterior communicating artery (AcoA) complex (31.2%), symmetric caudal basilar fusion (26.2%), antero-inferior cerebellar artery-postero- inferior cerebellar artery (AICA-PICA) (15.6%), extradural origin of the PICA (10.6%), cavernous origin of the ophthalmic artery or dorsal ophthalmic artery (dOPH) (3.5%). Some aneurysm locations were associated with a high rate of vascular anomalies, e.g.: posterior cerebral aneurysm with asymmetric caudal fusion, AcoA aneurysm with AcoA complex variation, basilar tip aneurysm with extradural PICA or symmetric caudal fusion, PICA aneurysm with AICA-PICA, para-ophthalmic aneurysm with dOPH. These aneurysm locations bled proportionally more frequently when associated with the related vascular anomaly. In conclusion, these results suggest that vascular anomalies are associated with aneurysm development and bleeding.

The surgical management of contralateral anterior circulation intracranial aneurysms

This study reviews the surgical management of contralateral anterior circulation aneurysms in patients with bilateral intracranial aneurysms repaired following a unilateral craniotomy. Between 1993 and 1999, 27 patients had 88 intracranial aneurysms repaired. Eleven patients presented following subarachnoid haemorrhage. Excluding midline aneurysms, 31 anterior circulation aneurysms were contralateral to the craniotomy and all were repaired at the same time that ipsilateral or midline aneurysms were repaired. Morbidity included one death and one case of loss of unilateral vision directly attributable to surgery and two cases of cerebral infarction due to vasospasm. No new neurological deficit or mortality could be directly attributed to the repair of a contralateral aneurysm. The repair of all accessible aneurysms, including those contralateral to the craniotomy, during one session avoids the risk of haemorrhage from incidental or unrecognised ruptured aneurysms (particularly during the aggressive treatment of vasospasm), avoids a second craniotomy, decreases overall hospitalisation and can improve visualisation of carotid-ophthalmic aneurysms.

Risk factors for the formation of multiple intracranial aneurysms

Object. Several factors are known to increase the risk of subarachnoid hemorrhage (SAH) and spontaneous intracerebral hematoma. However, information on the roles of these same factors in the formation of multiple aneurysms is less well defined. The purpose of this study was to examine factors associated with an increased risk of multiple aneurysm formation.

Methods. A retrospective review of the medical records of all patients with a diagnosis of SAH and intracranial aneurysms who were admitted to a single institution between 1985 and 1997 was undertaken. The authors examined associations between risk factors (patient age and sex, menopausal state of female patients, hypertension, cigarette smoking, alcohol consumption, history of cardiovascular disease or diabetes mellitus, and family history of cerebrovascular disease) and the presence of multiple aneurysms by using the Fisher exact test and logistic regression analysis. Of 400 patients admitted with a diagnosis of cerebral aneurysms, 392 were included in the study (287 women and 105 men). Two hundred eighty-four patients harbored a single aneurysm and 108 harbored multiple aneurysms (2 aneurysms in 68 patients, three aneurysms in 22 patients, four aneurysms in 13 patients, and five aneurysms in five patients).

Conclusions. Statistical analysis revealed that, as opposed to the occurrence of a single aneurysm, there was a significant association between the presence of multiple aneurysms and hypertension (p < 0.001), cigarette smoking (p < 0.001), family history of cerebrovascular disease (p < 0.001), female sex (p < 0.001), and postmenopausal state in female patients (p < 0.001).

Influence of smoking, hypertension, and sex on the phenotypic expression of familial intracranial aneurysms in siblings

OBJECTIVE

To investigate the effects of smoking, hypertension, and sex on the phenotypic expression of familial intracranial aneurysms (FIAs).

METHODS

We retrospectively reviewed the case records of 806 consecutive patients undergoing aneurysm surgery at our institution (1986-1995) and discovered 24 families with at least two affected siblings. Prevalence rates for the smoking, hypertension, and sex risk factors in these nuclear families were compared with those of patients with sporadic intracranial aneurysms (SIAs) and population-based control patients.

RESULTS

Affected family members with FIAs exhibited prevalence rates of smoking and hypertension (74% and 43%, respectively) that tended to be higher than those of population-based control patients (52% [P < 0.005] and 36% [P = not significant (NS)], respectively) and comparable to those of patients with SIAs (64% [P = NS] and 40% [P = NS], respectively). A positive association existed between FIA formation and female sex but was somewhat less strong than that observed in the SIAs (59% FIAs, 71% SIAs, 50% control patients). In addition, the prevalence rates of smoking, hypertension, and female sex were higher in affected family members with FIAs than in their unaffected siblings (58% [P < 0.05], 28% [P = 0.06], and 39% [P < 0.05], respectively). Individuals in families with expressed FIAs who had high aneurysmal penetrance had a greater tendency to be smokers, hypertensive, and female (74%, 59%, and 55%, respectively) than did their low-penetrance counterparts (61% [P = 0.1], 27% [P < 0.05], and 45% [P = NS], respectively).

CONCLUSION

Together these data suggest that hypertension, smoking, and female sex increase the likelihood that a member of a family with an expressed FIA will have an aneurysm. These observations may prove helpful in guiding the use of screening studies and encouraging education about the potential risks of continued tobacco use and untreated hypertension in this patient cohort.

Impact of Guglielmi detachable coils on outcomes of patients with intracranial aneurysms treated by a multidisciplinary team at a single institution

OBJECT

The goal of this study was to investigate the impact of the introduction of the Guglielmi detachable coil (GDC) therapeutic option on the overall management outcome of intracranial aneurysms. The authors accomplished this by assessing patient morbidity and mortality, inflation-adjusted hospital charges, lengths of stay in the hospital and the intensive care unit (ICU), and treatment efficacy.

METHODS

The authors conducted a retrospective analysis of consecutive cases of intracranial intradural aneurysms managed by a single multidisciplinary neurovascular team at a tertiary care, academic referral center during the 24 months preceding the introduction of the GDC procedure (Group I or pre-GDC era, 77 patients) and during the first 24 months after its introduction (Group II or GDC era, 99 patients). Treatment with GDCs was considered for cases of higher clinical grade or poor surgical risk, or in response to patient preference (27 [27%] of 99 patients in Group II). Host and lesion parameters in our cohort were validated against outcome parameters by using univariate and multivariate analyses. The pre-GDC and GDC subgroups of patients were comparable for major disease severity parameters (patient age, lesion location, clinical grade, and hemorrhage severity). There was no significant difference in clinical outcome at 6 months, infarcts on computerized tomography scanning, or aneurysm obliteration rates before and after introduction of GDC treatment. Decreasing trends in duration of hospital and ICU stay and in inflation-adjusted hospital charges occurred well before and thus were unrelated to the introduction of the GDC therapeutic option.

CONCLUSIONS

The results of this study do not demonstrate any significant impact of integration of the GDC modality on clinical outcome, mortality, morbidity, or effectiveness of treatment. Ongoing improvements in hospital charges and length of hospital stay appeared unrelated to the introduction of the GDC option.

Intracranial aneurysms and arterial hypertension: a review and hypothesis

BACKGROUND

Intracranial aneurysms and systemic arterial hypertension coexist in a high percentage of patients. The relationship between intracranial aneurysms and hypertension is poorly defined.

METHODS

Therefore, we reviewed the role of hypertension in the pathogenesis of saccular aneurysms as previously reported in clinical, experimental, and autopsy studies.

RESULTS

Among 24 relevant clinical and/or autopsy studies, the mean incidence of pre-existing hypertension was 43.5% in aneurysm patients compared to 24.4% in the normal population. Although definitive evidence is lacking, data from multiple types of investigations indicate that systemic arterial hypertension creates a greater risk for the development of intracranial aneurysms than previously believed. The underlying pathophysiological mechanism(s) are also poorly defined.

CONCLUSIONS

We propose a unifying hypothesis: Endothelial injury, occlusion of the vasa vasorum, and disruption of the synthesis of collagen and elastin are likely the most important factors in initiating the development of aneurysms. Chronic hypertension potentially affects all of these factors. Consequently, chronic hypertension may cause intimal thickening, necrosis of the tunica media, changes in the compositional matrix, and degeneration of the internal elastic lamina to develop in the arterial wall. These structural changes could cause a focal weakening in the arterial wall with resultant bulging. This theory accounts for the high incidence of intracranial aneurysms in the absence of any known associated hereditary or connective-tissue disease. Nor does it exclude the possibility of other etiological factors. From the perspective of prevention, however, it offers clear opportunities for prophylaxis.

Catecholamine-secreting carotid body tumor and intracranial aneurysm: coincidence?

BACKGROUND

An extremely rare case of intracranial aneurysm associated with catecholamine-secreting carotid body tumor is presented.

CASE DESCRIPTION

A 64-year-old woman suffering from hypertensive attacks was admitted first to the Otolaryngology Department with a neck swelling. Right common carotid angiography revealed a hypervascular mass at the carotid bifurcation. On the same angiogram a middle cerebral artery aneurysm was discovered incidentally and the patient was referred to the Neurosurgical Department. Because of her history the tumor was considered to be endocrinologically active and the patient underwent alpha- and beta-blockade to protect intraoperative cardiovascular instability. Despite all precautions, during the operation hypertensive crises developed and the aneurysm was clipped with difficulty.

CONCLUSION

Perioperative management designed to avoid complications in treating this rare association is discussed. Although this is the first reported case of an intracranial aneurysm associated with a functional carotid body tumor, a possible etiopathogenesis of the relationship between the aneurysm and hypertensive attacks due to an acute catecholamine-discharging tumor is presented.

Risk factors for multiple intracranial aneurysms

BACKGROUND AND PURPOSE

The presence of multiple intracranial aneurysms may be a sign of significant risk factors for aneurysm formation that differ from those factors that increase risk for aneurysm rupture. Only 2 studies concern independent risk factors for multiple aneurysms, and the results are in part controversial. This study was designed to identify independent risk factors for multiple intracranial aneurysms in patients with subarachnoid hemorrhage.

METHODS

Of 266 patients with aneurysmal subarachnoid hemorrhage (139 men and 127 women, aged 15 to 60 years), 80 (30%) had multiple intracranial aneurysms. The prevalence of several health-related habits, previous diseases, and medications of these patients were compared by multiple logistic regression between those with single and those with multiple aneurysms.

RESULTS

On the basis of multivariate statistics, only regular cigarette smoking at any time was a significant risk factor for the presence of multiple aneurysms. The odds ratio (OR) of smoking for multiple aneurysms was 2.10 (95% CI, 1.06 to 4.13) after adjustment for age and sex. After additional adjustment for hypertension, the risk was 2.06 (95% CI, 1. 04 to 4.07). Of other variables, only age (OR, 1.02 per year; 95% CI, 1.00 to 1.05; P=0.09) and female sex (OR, 1.60; 95% CI, 0.90 to 2. 85; P=0.11) showed a tendency to increase the risk for multiple aneurysms after adjustment for smoking. On the other hand, patients with hypertension had significantly (P=0.029) more aneurysms (1. 61+/-1.04) than did those without (1.37+/-0.68), although they did not more frequently have multiple aneurysms.

CONCLUSIONS

Cigarette smoking and possibly also age and female sex seem to be risk factors for multiple intracranial aneurysms in patients of working age who have suffered a subarachnoid hemorrhage. Patients with hypertension seem to have more aneurysms than those without.

Experimental cerebral aneurysms in the female heterozygous Blotchy mouse

The Blotchy mouse is characterized by an X-linked inherited disorder of connective tissue synthesis. The susceptibility to aneurysm formation in the cerebral arteries of the circle of Willis was compared in female heterozygous 'Blotchy' and control mice subjected to unilateral carotid artery ligation either alone or associated with hypertension. Cerebral aneurysms developed only in hypertensive Blotchy mice (6/31 vs. 0/30 in hypertensive controls). Aneurysms of the aorta and its major branches occurred in normotensive mice only in the Blotchy group in which hypertension increased the incidence of mesenteric and coeliac aneurysms. A light microscopic study of interruptions of the internal elastic lamina (IIEL) showed that they developed in arteries of both Blotchy and control mice but to a greater extent in the Blotchy group where hypertension further increased their incidence. The IIEL incidence in the aortic arch varied in parallel to the occurrence of aneurysms in all the different arterial sites. Thus, in an apparently normally viable animal, the presence of a mutated gene which indirectly leads to defective elastin and collagen fibre synthesis, favours the formation of both peripheral and cerebral aneurysms. However, the development of cerebral aneurysms requires the addition of an increase in haemodynamic stress.

De novo formation of familial cerebral aneurysms: case report

OBJECTIVES

The factors regulating the formation and growth of cerebral aneurysms are poorly understood. We report the case of a patient whose grandfather had a cerebral aneurysm and who developed numerous de novo aneurysms of varying size 9 years after the treatment of a first aneurysm. This observation sheds light on the cause and growth of cerebral aneurysms in familial cases that may be pertinent to sporadic cases.

CLINICAL PRESENTATION

A 58-year-old man was admitted to the Montreal Neurological Institute in 1956 for an ultimately fatal, autopsy-proven, ruptured internal carotid artery aneurysm. His granddaughter was first admitted to the same institution in 1984 after suffering a subarachnoid hemorrhage from a ruptured right terminal internal carotid artery aneurysm that was successfully treated. Four-vessel cerebral angiography did not reveal other aneurysms. The granddaughter was readmitted to the hospital 9 years later after a new, lumbar puncture-proven subarachnoid hemorrhage occurred. Cerebral angiography demonstrated that the previously clipped aneurysm did not fill. However, five new aneurysms were present.

INTERVENTION

An anterior communicating artery aneurysm, thought to be the one that bled, was surgically clipped, and a large right posterior communicating artery aneurysm was coiled endovascularly. The remaining, smaller aneurysms were left untreated.

CONCLUSION

The appearance of five new aneurysms during a 9-year interval suggests that there may be a genetic factor operating in the development of cerebral aneurysms in families and that this may produce a more widespread cerebral arteriopathy than is generally appreciated. Patients with treated cerebral aneurysms from families in which two or more individuals have cerebral aneurysms, and perhaps their first and second degree relatives who have had negative angiograms, should be considered for periodic follow-up cerebrovascular imaging to rule out the subsequent development of de novo aneurysms.

Risk factors for multiple intracranial aneurysms

OBJECTIVE

Risk factors that predispose to the formation of multiple intracranial aneurysms, which are present in up to 34% of patients with intracranial aneurysms, are not well defined. In this study, we examined the association between known risk factors for cerebrovascular disease and presence of multiple intracranial aneurysms.

METHODS

We reviewed the medical records and results of conventional angiography in all patients with a diagnosis of intracranial aneurysms admitted to the Johns Hopkins University hospital between January 1990 and June 1997. We determined the independent association between various cerebrovascular risk factors and the presence of multiple aneurysms using logistic regression analysis.

RESULTS

Of 419 patients admitted with intracranial aneurysms (298 ruptured and 121 unruptured), 127 (30%) had multiple intracranial aneurysms. In univariate analysis, female gender (odds ratio [OR] = 1.9; 95% confidence interval [CI], 1.1-3.3) and cigarette smoking at any time (OR = 1.8; 95% CI, 1.1-3.0) were significantly associated with presence of multiple aneurysms. In the multivariate analysis, cigarette smoking at any time (OR = 1.7; 95% CI, 1.1-2.8) and female gender (OR = 2.1; 95% CI 1.2-3.5) remained significantly associated with multiple aneurysms. Hypertension, diabetes mellitus, and alcohol and illicit drug use were not significantly associated with presence of multiple aneurysms.

CONCLUSION

Cigarette smoking and female gender seem to increase the risk for multiple aneurysms in patients predisposed to intracranial aneurysm formation. Further studies are required to investigate the mechanism underlying the association between cigarette smoking and intracranial aneurysm formation.

Risk classification after aneurysmal subarachnoid hemorrhage

BACKGROUND

Prediction of patient outcome is an important aspect of the management and study of aneurysmal subarachnoid hemorrhage (SAH). In the present study, we evaluated the prognostic value of two multivariate approaches to risk classification, Classification and Regression Trees (CART) and multiple logistic regression, and compared them with the best single predictor of outcome, level of consciousness.

METHODS

Data prospectively collected in the first Cooperative Aneurysm Study of intravenous nicardipine after aneurysmal SAH (NICSAH I, n = 885) were used to develop the prediction models. Low-, medium-, and high-risk groups for unfavorable outcome were devised using CART and a stepwise logistic regression analysis. Admission factors incorporated into both classification schemes were: level of consciousness, age, location of aneurysm (basilar versus other), and the Glasgow Coma Score. The CART prediction tree also branched on a dichotomy of admission glucose level. The two multivariate classifications were then compared with a prediction scheme based on the single best performing prognostic factor, level of consciousness in an independent series, NICSAH II (n = 353), and also in the original training dataset.

RESULTS

A similar discrimination of risk was achieved by the three classification systems in the testing sample (NICSAH II). The 8%, 19%, and 52% rates of unfavorable outcome obtained from low-, medium-, and high-risk groups defined by LOC approximated those obtained using the more complex multivariate systems.

CONCLUSION

Although multivariate classification systems are useful to characterize the relationship of multiple risk factors to outcome, the simple clinical measure LOC is favored as a concise and practical classification for predicting the probability of unfavorable outcome after aneurysmal SAH.

Intracranial aneurysms associated with aortitis syndrome: case report and review of the literature

OBJECTIVE AND IMPORTANCE

Aortitis syndrome is a systemic vasculitis of unknown etiology, affecting mainly the major branches of the aorta and leading to stenosis or occlusion. Intracranial aneurysms are rarely associated with this syndrome. Only 15 cases have been previously reported.

CLINICAL PRESENTATION

A 54-year-old woman with a 10-year history of aortitis syndrome demonstrated nonruptured cerebral aneurysms in the left internal carotid and anterior communicating arteries, with decreased flow in the right internal carotid artery and ipsilateral A1 segment.

INTERVENTION

The patient underwent clipping of the aneurysms through a left pterional craniotomy and transsylvian approach.

CONCLUSION

In our review of 16 reported cases, including the present case (13 with ruptured aneurysms and 3 with nonruptured aneurysms), there were 25 saccular aneurysms, and we noted the following clinical characteristics: 1) patient age was 26 to 64 years, with an average of 50.2 years; 2) aneurysms arose predominantly along the course of collateral flow, especially in the vertebrobasilar system (13 of 25 aneurysms, 52.0%); 3) there was a high incidence of multiplicity (7 of 16 cases, 43.8%). These characteristics suggest that increased hemodynamic stress, produced by stenosis or occlusion of the major branches of the aorta and systemic hypertension, plays an important role in the development of cerebral aneurysms in patients with this syndrome.

Pheochromocytoma and multiple intracranial aneurysms: is it a coincidence? Case report

The authors present a case of multiple intracranial aneurysms associated with a pheochromocytoma. The aneurysms were successfully clipped, and a suprarenal tumor located on the left side was totally removed. To the authors' knowledge this is the fourth reported case of these combined entities in the literature. The authors speculate on the possible etiopathogenesis of the relationship between intracranial aneurysms and attacks of hypertension caused by the presence of neoplasms that discharge acute and irregular levels of catecholamines, especially pheochromocytomas. Perioperative management designed to avoid undesired complications in this rare association is also discussed.

Epidemiological study of reptured intracranial aneurysms in the Saguenay-Lac-Saint-Jean region (Quebec, Canada)

BACKGROUND

Using a population-based register of the Saguenay-Lac-Saint-Jean region (Quebec, Canada), the genealogical reconstruction of 533 individuals with intracranial aneurysm (IA) showed a familial aggregation (the presence of aneurysm in two or more first- to third-degree relatives) for 159 (29.8%) of them; this proportion is much higher than reported elsewhere.

OBJECTIVE

As part of an ongoing project to assess a genetic predisposition to intracranial aneurysms in the Saguenay-Lac-Saint-Jean population, the objective of the present study was to determine whether age-specific rates of reputed cerebral aneurysms were higher than in other populations.

DESIGN

A retrospective study of cases of proven ruptured IAs which were hospitalized during the 1973 to 1992 period was conducted. Age-adjusted rates were computed and compared to those reported in the Helsinki population.

RESULTS

We identified 412 cases of ruptured aneurysms. The age-adjusted incidence rate was 7.2/100,000/year (6.2 for men, 8.1 for women), which is similar to the incidence rates reported in other studies. Although the mean age at time of rupture was younger (46.6 years +/- 13.8) than usually reported, no increase in age-specific incidence rates was detected.

CONCLUSIONS

The results of this epidemiological study neither support nor reject the hypothesis of a genetic predisposition to intracranial aneurysms in the Saguenay-Lac-Saint-Jean population.

Familial cerebral aneurysms. A bias for women

BACKGROUND AND PURPOSE

We evaluated the influence of gender on the formation and rupture of familial cerebral aneurysms.

METHODS

We studied 30 patients with ruptured cerebral aneurysms from 14 consecutive families. These patients were compared with the patients with sporadic aneurysms reported by the first Cooperative Study.

RESULTS

Eighty percent of familial aneurysms occurred in women versus 59% of sporadic aneurysms (P < .05, chi 2 test). This overrepresentation of women occurred at below the age of 50 years, where 78% of patients with familial aneurysms were women compared with 45% for sporadic aneurysms (P < .01, chi 2 test). Above this age, there was no statistical difference in incidence of familial aneurysms in men or women compared with sporadic aneurysms. In women with familial aneurysms, rupture occurred before the age of 50 years in 59%, compared with 31% for sporadic aneurysms (P < .01, chi 2 test). In four of five families, aneurysms ruptured within 10 years of each other in sisters (mean, 6 years). Multiple aneurysms were equal in both groups (17%), but multiple familial aneurysms occurred mainly in women. There was no difference in the site of single cerebral aneurysms in either group, but familial aneurysms in females occurred at the same site in five of eight families (62%) and in 11 of 17 mother-daughter or sister pairs (65%), compared with 20% for two randomly selected sporadic aneurysms (P < .01).

CONCLUSIONS

There is an overrepresentation of women with ruptured familial aneurysms compared with those with sporadic aneurysms. Familial aneurysms rupture in females predominantly before the age of 50, in the same decade, and at the same site within families in the majority of cases. These observations support a possible genetic cause for cerebral aneurysms and a possible hormonal contribution to their rupture.