Family history of subarachnoid hemorrhage and the incidence of asymptomatic, unruptured cerebral aneurysms.

OBJECT: Previously the authors reported a significant correlation between a family history of subarachnoid hemorrhage (SAH) and the discovery of an unruptured aneurysm in a group of healthy volunteers. This study corroborates and extends previous findings regarding the relationship between genetic and acquired factors in the formation of cerebral aneurysms. METHODS: The incidence of asymptomatic, unruptured cerebral aneurysms was studied among patients with a family history of SAH within the second degree of consanguinity. Forty-one unruptured cerebral aneurysms were found in 34 (13.9%) of 244 patients. This incidence was significantly higher than that found in a control group of healthy volunteers (6%). Furthermore, patients who had a family history of SAH combined with multiple systemic risk factors were found to have the highest incidence of unruptured aneurysms (32%; odds ratio 3.49, 95% confidence interval 1.37-8.9). CONCLUSIONS: These findings suggest that patients with a family history of SAH with or without the presence of more than one systemic risk factor are at significantly higher risk of harboring cerebral aneurysms. This high-risk group should be periodically screened and treated with appropriate surgical or other forms of therapy when necessary.     

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

BackgroundPrevention 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.MethodsThis 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.ResultsAfter 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.ConclusionIdentification of risk factors for aneurysm formation and rupture separately seems to be pivotal for reducing the incidence of SAH.     

Long-term prognosis in patients with clipped unruptured cerebral aneurysms―increased cerebrovascular events in patients with surgically treated unruptured aneurysms

We retrospectively investigated surgical immediate and long-term overall results after clipping of the unruptured aneurysms. Between 1991 and 2008, 166 patients underwent neck clipping of unruptured saccular aneurysms at our institute. Patients were subsequently followed to clarify the occurrence of subarachnoid hemorrhage (SAH), and stroke other than SAH, aneurysm recurrence, cerebrovascular death, all-cause death, and risk factors. Surgical complication was noted in 14 patients (8.4 %) and surgical morbidity in two patients (1.2 %). Of 164 patients except for these two patients who suffered surgical morbidity, we could obtain more than 3 years follow-up information for 144 patients (87.8 %). There were 49 men and 95 women. The mean age was 58.5 years, and mean follow-up period was 7.9 years. Eight cases had died during follow-up (hepatic insufficiency in one, renal insufficiency in one, suicide in one, intracerebral hemorrhage (ICH) in two, SAH in one, and pneumonia after stroke in two). Therefore, the cause of death was stroke and late effects of stroke. Twelve symptomatic cerebrovascular events (cerebral infarction in seven, ICH in four, and SAH in one) occurred in ten patients. Consequently, annual risk of SAH after clipping of unruptured aneurysms was 0.085 %. Besides, annual risk of stroke in those patients was 1.06 %, and this incidence was higher than that in the general population. Although this study confirmed the good surgical result, annual risk of stroke after clipping of unruptured aneurysms was much higher than that in the general population. The long-term periodic examination to detect recurrent aneurysms and appropriate management to prevent stroke should be performed for patients with surgically treated unruptured aneurysm.     

Subarachnoid hemorrhage in the presence of both intracranial dissecting and saccular aneurysms--two case reports

Two patients presented with subarachnoid hemorrhage (SAH) associated with both intracranial dissecting and saccular aneurysms. Case 1, a 48-year-old woman, had a saccular aneurysm of the right internal carotid artery and dissecting aneurysms of the bilateral vertebral arteries. Case 2, a 52-year-old man, had three saccular aneurysms in the anterior circulation and a dissecting aneurysm of the unilateral vertebral artery. A saccular aneurysm was responsible for the SAH in both patients. Ruptured saccular aneurysms were treated with surgical clipping and unruptured dissecting aneurysms remained untreated. SAH recurred due to bleeding from an untreated dissecting aneurysm 4 days after the initial SAH in Case 1. Triple-H therapy, which causes increased hemodynamic stress, was not administered for symptomatic cerebral vasospasm after SAH in Case 2, because of the risk of bleeding from the untreated dissecting aneurysm, and the patient suffered cerebral infarction. The risk factors for this rare association are unclear, but both patients were smokers and had hypocholesterolemia including low apolipoprotein E levels. The clinical management of patients with SAH and both dissection and saccular aneurysms is complicated. Asymptomatic dissecting aneurysm has a benign clinical course in general, but hemodynamic stress related to stroke may induce abrupt development of dissecting aneurysms. Prophylactic obliteration during the acute stage of SAH may provide better outcomes if the unruptured dissecting lesion appears as obvious aneurysmal dilatation or pearl-and-string sign and is safely treatable with endovascular trapping.     

Problems of surgical treatment for multiple intracranial aneurysms]

A series of 105 patients presenting with multiple aneurysms and subarachnoid hemorrhage (SAH) were operated on for ruptured and unruptured aneurysms between 1976 and 1984. Clinical factors other than the severity of SAH affecting the outcomes included: 1) Misdiagnosis of the location of a ruptured aneurysm among multiple aneurysms resulted in poor outcomes because of multiple surgical approaches or rebleeding during the acute period. 2) Combinations of aneurysmal locations requiring multiple surgical approaches, such as interhemispheric and transsylvian, during the acute stage caused worse outcomes than with multi-stage surgeries. If an unruptured aneurysm could not be reached during the initial exposure, multi-stage surgery was safe if the ruptured aneurysm had been clipped during the acute period. 3) Complications occurring during unruptured aneurysm surgery. The patient's age, the location and size of the unruptured aneurysms were significant factors in the clinical prognosis. Surgery for unruptured aneurysm caused 1.8% morbidity in patients between 28 and 55 years, but 18.0% morbidity in patients over 56 years of age. Surgery for internal carotid artery aneurysms resulted in 14.8% overall morbidity. Surgery for middle cerebral and anterior cerebral artery aneurysms caused below 5% morbidity. Postoperative morbidity in patients with aneurysms less than 5 mm in diameter was 1.3%, and with aneurysms measuring 10 mm or more, 20%. The optimum treatment for multiple aneurysms with SAH should be based on all factors of the patient's condition, including the unruptured 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).     

De novo formation and rupture of an azygos pericallosal artery aneurysm. Case report

An azygos pericallosal artery (APCA) aneurysm is a rare anomaly that is closely associated with saccular aneurysms. This is the earliest report to document de novo formation and rupture of an aneurysm at the bifurcation of an unpaired pericallosal trunk. The authors report the case of a woman who presented at the age of 52 years with subarachnoid hemorrhage (SAH) from the rupture of a newly formed APCA bifurcation aneurysm, 7 years after she had undergone surgery to clip a ruptured anterior cerebral artery aneurysm. De novo formation of aneurysms after SAH rarely occurs and certain risk factors like multiple and familial aneurysms, arterial hypertension, or smoking have been postulated. Late follow-up examination with angiography to detect de novo aneurysms should be considered in patients with this vascular anomaly after SAH.     

Characteristics of aneurysms arising from the horizontal portion of the anterior cerebral artery

BACKGROUND: Aneurysms arising from the proximal portion of the anterior cerebral artery (A1: horizontal portion) are quite rare and are considered to be unique, because they are usually connected with other vascular anomalies and are sometimes part of a multiple aneurysm occurrence. A1 aneurysm cases experienced over the past seven and a half years are summarized in this paper. METHODS: A total of 413 patients were surgically treated including 142 patients with subarachnoid hemorrhage (SAH); the remaining 271 patients had unruptured aneurysms. Among them, nine cases were categorized as constituent A1 aneurysms, three with SAH and six with unruptured aneurysms. RESULTS: The shape of the aneurysm was saccular in all nine cases. Three of the nine cases had associated vascular malformations. The average aneurysm diameter in the three cases with SAH was 4.0 mm, which is smaller than other common aneurysms presenting with SAH. Eight aneurysms developed at the takeoff point of perforating arteries-the medial lenticulostriate artery in five cases and the recurrent artery of Heubner in three cases. In the remaining case, the aneurysm originated from the proximal end of the associated A1 fenestration. All nine patients had an excellent outcome after surgery. CONCLUSION: A1 aneurysms require surgical elimination even if they are small. We emphasize the importance of preserving the blood flow of these perforating arteries by avoiding compression with either the clip blade or the clip body itself.     

Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture

OBJECT: The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed. METHODS: One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using life-table analyses and Cox's proportional hazards regression models including time-dependent covariates. The median follow-up time was 19.7 years (range 0.8-38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1-1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93-1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04-2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21-7.66, p = 0.02). CONCLUSIONS: Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.     

Natural history of unruptured intracranial aneurysms: probability of and risk factors for aneurysm rupture

OBJECT: The authors conducted a study to investigate the long-term natural history of unruptured intracranial aneurysms and the predictive risk factors determining subsequent rupture in a patient population in which surgical selection of cases was not performed. METHODS: One hundred forty-two patients with 181 unruptured aneurysms were followed from the 1950s until death or the occurrence of subarachnoid hemorrhage or until the years 1997 to 1998. The annual and cumulative incidence of aneurysm rupture as well as several potential risk factors predictive of rupture were studied using lifetable analyses and Cox's proportional hazards regression models including time-dependent covariates. The median follow-up time was 19.7 years (range 0.8-38.9 years). During 2575 person-years of follow up, there were 33 first-time episodes of hemorrhage from previously unruptured aneurysms, for an average annual incidence of 1.3%. In 17 patients, hemorrhage led to death. The cumulative rate of bleeding was 10.5% at 10 years, 23% at 20 years, and 30.3% at 30 years after diagnosis. The diameter of the unruptured aneurysm (relative risk [RR] 1.11 per mm in diameter, 95% confidence interval [CI] 1-1.23, p = 0.05) and patient age at diagnosis inversely (RR 0.97 per year, 95% CI 0.93-1, p = 0.05) were significant independent predictors for a subsequent aneurysm rupture after adjustment for sex, hypertension, and aneurysm group. Active smoking status at the time of diagnosis was a significant risk factor for aneurysm rupture (RR 1.46, 95% CI 1.04-2.06, p = 0.033) after adjustment for size of the aneurysm, patient age, sex, presence of hypertension, and aneurysm group. Active smoking status as a time-dependent covariate was an even more significant risk factor for aneurysm rupture (adjusted RR 3.04, 95% CI 1.21-7.66, p = 0.02). CONCLUSIONS: Cigarette smoking, size of the unruptured intracranial aneurysm, and age, inversely, are important factors determining risk for subsequent aneurysm rupture. The authors conclude that such unruptured aneurysms should be surgically treated regardless of their size and of a patient's smoking status, especially in young and middle-aged adults, if this is technically possible and if the patient's concurrent diseases are not contraindications. Cessation of smoking may also be a good alternative to surgery in older patients with small-sized aneurysms.     

Natural history of unruptured cerebral aneurysms of the unoperated and observed cases

PURPOSE: Natural history of unruptured cerebral aneurysms is still a matter of discussion. In this study, we investigated the prognosis of unruptured cerebral aneurysms of unoperated cases in a prospective design. METHODS: Between September, 1992 and December, 2001, we have encountered a 256 cases of unruptured cerebral aneurysms. Among them, 118 cases were observed and were checked every year for their status. The endpoint was designed as their death and aneurysm rupture. Their rupture rate, mortality due to aneurysm death, and the cause of death other than aneurysm were investigated. Univariate analysis, chi-square test was used as statistics. A p-value less than 0.05 was considered as significant. RESULTS: Annual rupture rate of unoperated unruptured cerebral aneurysms of size below 5 mm, between 5-15 mm, and over 15 mm increased according to the aneurysm size, 0.4%, 3.3% and 9.9% respectively. The sole risk factor for the feasibility of rupture of unruptured aneurysms was their size (p < 0.001). Aneurysm related mortality, however, was high in posterior circulation aneurysms. In patients under 70 years of age, 45% of patients died of cerebral aneurysms, but this rate decreased to 17% for patients over 70 years of age. CONCLUSION: The rupture rate of unruptured cerebral aneurysms over 5 mm in size is not low. Unruptured aneurysms of the posterior circulation may have a much higher risk of rupture, so further investigation is necessary.     

Screening of risk groups for discovering intracranial aneurysms before rupture

In development of intracranial aneurysms contribute genetic factors together with smoking, hypertension, diabetes mellitus. Epidemiology studies suggest that as many as 5% of people harbour a cerebral aneurysm by age 75. Rupture of cerebral aneurysm is the most frequent cause of spontaneous subarachnoid haemorrhage (up to 80%.) Annual incidence of SAH is 10-14/100 000, but only 15-20% of aneurysms will rupture, and that will happen probably between 40-60 years. The morbidity and mortality of aneurismal subarachnoid (SAH) continues to be high. It is not possible to predict who has aneurysm and is it going to bleed or not, but it is possible to reveal high risk groups (polycystic kidney disease, Ehlers-Danlos sy, Marphan sy, family history of cerebral aneurysms, suspect de novo aneurysm formation in patients with prior history of cerebral aneurysm). Reviewing data from literature and reporting cases from each group with high risk, that have been screened and aneurysms discovered, authors wish to focus interest on this matter and propose screening program for these groups of patients. The mortality and morbidity in cases treated before rupture is significantly lower than after SAH, so screening programs could save many lives. According to our preliminara data, mostly based on control angiographies after 8-10 zears in patients previouslz operated for intracranial aneurysmas, from 15 angipgraphies 4 revealed new aneurysms (26% in 10 years period) with total number of 6 de novo formed aneurysms, which is not valid due to small number of patients but strongly suggests the importancy of screening program for risk groups.     

Complications of endovascular treatment of cerebral aneurysms

BACKGROUND: The International Subarachnoid Aneurysm Trial has indicated that endovascular management of acutely ruptured aneurysms may be superior to surgery. Clearly poor results ensue from both forms of treatment, and some of these are because of technical complications (not just poor patient status). This observational study was performed to determine the complications associated with the endovascular treatment of ruptured and unruptured cerebral aneurysms. METHODS: Prospective data were gathered on 118 patients undergoing 126 endovascular treatment sessions for 126 nontraumatic cerebral aneurysms (30% unruptured) over a 3-year period. The average age was 51 years (range, 12-85 years). Females comprised 75% of the population treated. RESULTS: Good outcomes were achieved with 71% of the procedures (59% for subarachnoid hemorrhage [SAH]; 97% for unruptured). No bleeding or rebleeding occurred from treated aneurysms. Vessel or aneurysm perforation occurred in 11 cases and led to adverse outcome in 3 (3%). Thromboembolic complications were felt to cause cerebral infarction in 8 cases (6%). The risk of vessel/aneurysm rupture or thromboembolic stroke was greater in patients with SAH. Eight attempts to coil (6%) were initially unsuccessful. Two of these were later successfully coiled and others had surgery. None of the failed attempts led to clinical deterioration. Balloon-assisted coiling (BAC) was not associated with an increased complication rate. CONCLUSIONS: Vessel perforation and thromboembolic stroke are significant risks of endovascular treatment, especially after SAH. In our hands, however, BAC does not add to this risk.     

Outcome for unruptured middle cerebral artery aneurysm treatment: surgical and endovascular approach in a single center

The rupture of an intracranial aneurysm leads to subarachnoid hemorrhage (SAH). To prevent SAH, unruptured lesions can be treated by either endovascular or microsurgical approach. Due to their complex anatomy, middle cerebral artery (MCA) aneurysms represent a unique subgroup of intracranial aneurysms. Primary objective was to determine radiological and clinical outcomes in patients with middle cerebral artery aneurysms who were interdisciplinary treated by either endovascular or microsurgical approach in a single center. Secondary objective was to determine the impact of the lesions’ angiographic characteristics on treatment outcome. Clinical and radiological data of 103 patients interdisciplinary treated for unruptured MCA aneurysms over a 5-year period were analyzed in endovascular (n?=?16) and microsurgical (n?=?87) cohorts. Overall morbidity (Glasgow Outcome Score <5) after 12-month follow-up was 9 %. There was no significant difference between the two cohorts. Complete or “near complete” aneurysm occlusion was achieved in 97 and 75 % in the microsurgical, respective endovascular cohort. A “complex” aneurysm configuration had a significant impact on complete aneurysm occlusion in both cohorts, however, not on clinical outcome. Treatment of unruptured MCA aneurysms can be performed with a low risk of repair using both approaches. However, the risk for incomplete occlusion was higher for the endovascular approach in this series.     

Recent trends in the treatment of cerebral aneurysms: analysis of a nationwide inpatient database

OBJECT: The most appropriate treatment for cerebral aneurysms, both ruptured and unruptured, is currently under debate, and updated guidelines have yet to be defined. The authors attempted to identify trends in therapy for cerebral aneurysms in the US as well as outcomes. METHODS: The authors retrospectively reviewed data from the Nationwide Inpatient Sample hospital discharge database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality) for the period 1993-2003. Multiple variables were categorized and subjected to statistical analysis for International Classification of Diseases, 9th Revision, Clinical Modification codes related to subarachnoid hemorrhage (SAH), unruptured aneurysm, and clipping and endovascular treatment of cerebral aneurysm. RESULTS: During the study period, the numbers of discharges remained stable for SAH but doubled for unruptured aneurysms. Concomitantly, the number of aneurysms treated with clip placement remained stable, and the number treated by means of endovascular procedures doubled. By the study's end, the mortality rates had decreased 20% for SAH and 50% for unruptured aneurysms. Increasing age was associated with increased mortality rates, mean length of hospital stay (LOS), and mean charges (p < 0.01). Endovascular treatment was used more often in older patients (p < 0.01). Teaching status and larger hospital size were associated with higher charges and longer hospital stays (although the association was not statistically significant) and with better outcomes (p < 0.05) and lower mortality rates (p < 0.05), especially in patients who underwent aneurysm clipping (p < 0.01). Endovascular treatment was associated with significantly higher mortality rates in small hospitals (p < 0.001) and steadily increasing morbidity rates (45%). Morbidity rates, mean LOS, and mean charges were higher for aneurysm clipping (p < 0.01). CONCLUSIONS: From 1993 to 2003, endovascular techniques for aneurysm occlusion have been increasingly used, while the use of surgical clipping procedures has remained stable. Toward the end of the study period, better overall outcomes were observed in the treatment of cerebral aneurysms, both ruptured and unruptured. Large academic centers were associated with better results, particularly for surgical clip placement.     

Investigation of the surgically treated and untreated unruptured cerebral aneurysms of the anterior circulation

BACKGROUND: The natural history of unruptured cerebral aneurysms and the surgical risks are modified by several factors including size, location, and presence of subarachnoid hemorrhage (SAH). The main confusion arises because the backgrounds of the past reports describing the natural history or the surgical complication of unruptured cerebral aneurysms were different. The present study aimed to adjust the backgrounds and investigate the surgical indication with close monitoring of both surgically treated and untreated unruptured cerebral aneurysms. METHODS: In the past 9 years, 201 patients who had unruptured anterior circulation aneurysms were monitored. The decision of the operation was not randomized. The patients were divided into three subgroups by the size of the aneurysms (small group: below 5 mm, medium group: between 5 and 15 mm, large group: over 15 mm). In both surgically untreated and treated patients, overall mortality and morbidity corresponding to Rankin score II or worse was counted as unruptured aneurysm related event. The ratio of event free was compared between surgically treated and untreated patients using Log-rank test. RESULTS: In untreated patients, SAH was noted in 1 in the small group and 4 in the medium group. The annual rupture rate of the medium group was 12 times higher than that of the small group. In surgically treated patients, overall mortality and morbidity of the surgery was 2.3% in the small group, 3.6% in the medium group, and 20% in the large group. One surgically treated patient had SAH because of regrowth of aneurysm. When ratio of event free was compared, no significant advantage of surgery was noted in the small group and in all of the patients. However, the benefit of surgery was significant in the medium group (Log-rank p = 0.0189). CONCLUSIONS: The present results indicated that prophylactic surgery has a benefit for the medium-size aneurysms (5-15 mm) of the anterior circulation. For large aneurysms, individual investigation is necessary because of the variety of surgical difficulties, and the complex symptoms because of rupture and the mass effect as well as cerebral embolism. In small aneurysms, careful observation may be a reasonable choice unless the aneurysm is at a specially high risk of rupture.     

Retrospective analysis of the prevalence of asymptomatic cerebral aneurysm in 4518 patients undergoing magnetic resonance angiography--when does cerebral aneurysm develop?

The natural history of cerebral aneurysms was investigated by measuring the prevalence of incidentally found unruptured aneurysms in the general population and evaluating the characteristics including risk factors. 'De novo' formation of aneurysm was also demographically estimated. The prevalence of incidental aneurysm was evaluated among 4518 patients who underwent magnetic resonance (MR) angiography for various reasons in a neurosurgical institute. Double the number of patients were randomly selected from the remaining patients without aneurysm as the Control group so that sex and age group were matched to the Aneurysm group. 127 patients (2.8%) had diagnoses of aneurysm. The prevalence of asymptomatic aneurysm among middle-aged and elderly patients was predominant in women and increased with age in both sexes. Patients with aneurysms had significantly more hypertension and family history of subarachnoid hemorrhage compared to the controls. The prevalence was markedly increased in the 8th decade in men and the 7th decade in women, and new aneurysms seemed to develop predominantly around these decades. Cerebral aneurysms become detectable on MR angiography in the middle or later decades, and women tend to develop aneurysm earlier than men. Hypertension and family history of subarachnoid hemorrhage are probably risk factors for the development of aneurysm.     

Genesis of cerebral aneurysms--an update

To elucidate the molecular pathogenesis of diseases has become a crucial step in the development of new treatment strategies. Although the pathogenesis of cerebral aneurysms has been studied intensively, it is poorly understood. Endogenous factors like elevated arterial blood pressure, the special anatomy of the Circle of Willis or the effect of haemodynamic factors, particularly originating at vessel bifurcation, are all known to be involved in the growth and rupture of an aneurysm. There is an ongoing discussion as to whether these factors also contribute to the very early steps of pathogenesis. Arteriosclerosis and secondary inflammatory reactions are thought to be elementary preconditions. Exogenous factors like cigarette smoking, heavy alcohol consumption or certain medications known to help generate arteriosclerosis and elevated blood pressure have also been found to be related to the occurrence of cerebral aneurysms. Furthermore, there has been a long-lasting debate on whether aneurysms might develop as a result of an inborn genetic defect. First-degree relatives of patients with cerebral aneurysms have a higher risk of having an aneurysm. In addition, the elevated prevalence of cerebral aneurysms in patients suffering from various inherited diseases points to a genetic background in the development of an aneurysm. Recent advances in molecular biology provide evidence that genetic variants of different candidate genes are associated with the occurrence of cerebral aneurysms. The aim of this review is to expose the current status of these various hypotheses and their contribution to the pathogenesis of cerebral aneurysms in order to provide a basis for future investigations in this field.     

Genesis of Cerebral Aneurysms – An Update

Summary  To elucidate the molecular pathogenesis of diseases has become a crucial step in the development of new treatment strategies. Although the pathogenesis of cerebral aneurysms has been studied intensively, it is poorly understood. Endogenous factors like elevated arterial blood pressure, the special anatomy of the Circle of Willis or the effect of haemodynamic factors, particularly originating at vessel bifurcation, are all known to be involved in the growth and rupture of an aneurysm. There is an ongoing discussion as to whether these factors also contribute to the very early steps of pathogenesis. Arteriosclerosis and secondary inflammatory reactions are thought to be elementary preconditions. Exogenous factors like cigarette smoking, heavy alcohol consumption or certain medications known to help generate arteriosclerosis and elevated blood pressure have also been found to be related to the occurrence of cerebral aneurysms. Furthermore, there has been a long-lasting debate on whether aneurysms might develop as a result of an inborn genetic defect. First-degree relatives of patients with cerebral aneurysms have a higher risk of having an aneurysm. In addition, the elevated prevalence of cerebral aneurysms in patients suffering from various inherited diseases points to a genetic background in the development of an aneurysm. Recent advances in molecular biology provide evidence that genetic variants of different candidate genes are associated with the occurrence of cerebral aneurysms. The aim of this review is to expose the current status of these various hypotheses and their contribution to the pathogenesis of cerebral aneurysms in order to provide a basis for future investigations in this field.     

Surgical management of unruptured intracranial aneurysms personal experience with 37 cases and discussion of the indications

Summary The authors report a series of 37 cases of unruptured aneurysms, admitted and operated upon over a 5 year period (1985–1990), which represents an incidence of 18% of the total number of aneurysm patients operated upon during this period. These unruptured aneurysms were discovered in 4 types of circumstances: 1) Associated with a ruptured aneurysm but treated in a second procedure (9 cases); 2) After a transient ischaemic attack (6 cases); 3) After a cerebral haemorrhage of a different origin (3 cases), 4) After the onset of various neurological symptoms other than SAH (19 cases). Giant aneurysms (over 2.5 cm in diameter) are excluded from this series. Overall these 37 patients harboured 52 aneurysms, and 1 patient was operated upon on both sides. 27 aneurysms (52%) were located on the right side, 15 (29%) on the left side, and 10 (19%) on the midline. In the immediate post operative period, 1 patient died (2.6%) and 8 patients (21%) presented various complications. The outcome at 6 months was: death 2.6%, moderately disabled 8%, good recovery 89%.The arguments in favour of, or against, the surgical treatment of unruptured aneurysms are discussed in view of the literature. In favour of prophylactic surgery are: 1) The rather poor overall outcome following aneurysm rupture (including deaths before admission); 2) The rather good outcome of surgery in published series of unruptured aneurysms. The data of the natural history of the unruptured aneurysm are more questionable: in this view, surgery seems to be recommended in young patients with an easily accessible aneurysm and being in a good clinical condition. Several contra indications should be strictly accepted: severe associated diseases, age (over 65 and sometimes over 60), patient's refusal or reluctance. In cases of unruptured aneurysms to be operated upon in a second procedure after a ruptured aneurysm, the authors usually wait for 2 months or more before the second operation.