Using endothelial nitric oxide synthase gene polymorphisms to identify intracranial aneurysms more prone to rupture in Japanese patients

OBJECT: Recent investigators found that the presence of three tandem polymorphisms of the endothelial nitric oxide synthase (eNOS) gene-promoter single nucleotide polymorphism (SNP) T-786C, intron-4 27-bp variable number of tandem repeats, and the G894T SNP in exon 7-was indicative of intracranial aneurysms more prone to rupture in a Caucasian patient sample. In the present study, the authors sought to determine whether the presence of these eNOS polymorphisms could indicate which Japanese patients with aneurysms were more endangered by a subarachnoid hemorrhage (SAH). METHODS: The three eNOS polymorphisms were genotyped in 297 patients with ruptured aneurysms (RAs), 108 patients with unruptured aneurysms (UAs), and 176 healthy volunteers by using polymerase chain reaction. The distribution of the variant alleles did not differ significantly (p > 0.05) between the RA group and the UA group. The frequency of the corresponding genotypes between the two groups and a haplotype analysis did not show any significant differences. Further comparisons of the RA and UA groups with the control group did not yield any significant allele or genotype frequency differences. Conclusions. These data show that the examined set of eNOS polymorphisms were not indicative of which Japanese patients with intracranial aneurysms would suffer an SAH. The presence of eNOS polymorphisms is not useful in identifying intracranial aneurysms that are more prone to rupture in a Japanese patient sample.     

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

BACKGROUND: As the indication for surgical treatment of incidentally discovered small aneurysms remains controversial. METHODS: We retrospectively investigated the characteristics of small ruptured aneurysms and examined the relationship between the size and location of ruptured intracranial aneurysms and the sex, age, lifestyle, and medical history of 280 patients with ruptured aneurysm treated at our institute. RESULTS: The mean diameter of ruptured aneurysms in this series was 7.6 mm. In diameter, 135 (48.2%) ranged between 5 and 10 mm; 73 (26.1%) were smaller than 5 mm. The size of the ruptured aneurysms was significantly smaller (mean 6.5 mm) in patients with non- or poorly controlled hypertension than in normotensive patients (mean 8.3 mm) (p < 0.05). Ruptured aneurysms in the anterior communicating artery (AcomA) and anterior cerebral artery (ACA) were significantly smaller (p < 0.01) than those in the internal carotid artery or middle cerebral artery. Among 58 patients with multiple aneurysms, only 7 (12%) suffered rupture of aneurysms smaller than 5 mm (p < 0.01). Patients younger than 40 years and patients with a family history of subarachnoid hemorrhage appeared to predispose to the rupture of small-sized aneurysms, although those did not affect the statistical significance. CONCLUSIONS: This study shows that even aneurysms smaller than 10 mm may rupture. However, treatment decisions for unruptured aneurysm should not be based solely on the size of the unruptured aneurysms. Our data implies that even small aneurysms in the AcomA and ACA had an increased tendency for rupture, and that hypertensive patients were at higher risk for the rupture of small aneurysms.     

以蛛网膜下腔出血起病的颅内多发动脉瘤的诊治

【摘要】〓随着脑血管成像技术的广泛应用及不断提高,动脉瘤性蛛网膜下腔出血患者中多发动脉瘤检出率越来越高。研究表明既往有蛛网膜下腔出血病史患者的未破裂动脉瘤破裂风险要高于无蛛网膜下腔出血病史者,对于发生动脉瘤破裂的多发动脉瘤患者除明确责任动脉瘤并首先处理外,其未破裂动脉瘤也应尽量检出并积极治疗,因此多发动脉瘤的诊断和治疗均要比单发动脉瘤复杂。     

Influence of endothelial nitric oxide synthase T-786C single nucleotide polymorphism on aneurysm size

OBJECT: Among patients with aneurysms, those with heterozygous (T/C) endothelial nitric oxide synthase (eNOS) T-786C single nucleotide polymorphism (SNP), a mutation reducing endothelial nitric oxide synthesis, are reported to have larger ruptured intracranial aneurysms (IAs) than those with homozygous (C/C or T/T) genotype. The authors tested patients harboring aneurysms for eNOS T-786C SNP in two populations--Japanese and Korean. METHODS: The eNOS T-786C SNP was genotyped through direct sequencing in genomic DNA obtained from 336 Japanese and 191 Korean patients with lAs and 214 Japanese and 191 Korean control volunteers. Differences in genotype frequencies among the various aneurysm sizes were evaluated using the Fisher exact test. There was no significant difference in heterozygous (T/C) eNOS T-786C SNP between aneurysms 5 mm or smaller and those from 6 to 9 mm, and between lesions 5 mm or smaller and those 10 mm or larger in 336 Japanese patients harboring aneurysms--220 with ruptured and 116 with unruptured lesions--and in 191 Korean patients with ruptured aneurysms. CONCLUSION: The eNOS T-786C SNP genotype does not influence the size of aneurysms.     

Quantified aneurysm shape and rupture risk

OBJECT: The authors investigated whether quantified shape or size indices could better discriminate between ruptured and unruptured aneurysms. METHODS: Several custom algorithms were created to quantifiy the size and shape indices of intracranial aneurysms by using three-dimensional computerized tomography angiography models of the brain vasculature. Data from 27 patients with ruptured or unruptured aneurysms were evaluated in a blinded fashion to determine whether aneurysm size or shape better discriminated between the ruptured and unruptured groups. Five size and eight shape indices were calculated for each aneurysm. Two-tailed independent Student t-tests (significance p < 0.05) were used to determine statistically significant differences between ruptured and unruptured aneurysm groups for all 13 indices. Receiver-operating characteristic-area under curve analyses were performed for all indices to quantify the predictability of each index and to identify optimal threshold values. None of the five size indices were significantly different between the ruptured and unruptured aneurysms. Five of the eight shape indices were significantly different between the two lesion groups, and two other shape indices showed a trend toward discriminating between ruptured and unruptured aneurysms, although these differences did not reach statistical significance. CONCLUSIONS: Quantified shape is more effective than size in discriminating between ruptured and unruptured aneurysms. Further investigation will determine whether quantified aneurysm shape will prove to be a reliable predictor of aneurysm rupture.     

Unruptured intracranial aneurysms in elderly patients.

A total of 556 patients with 769 intracranial aneurysms, of which 256 were unruptured and 513 were ruptured, were included in the present study. The patients were divided into three age groups: those aged 59 years or younger, those aged 60 to 69 years, and those aged 70 years or older. Small aneurysms of 4 mm or less in diameter were more common in the series of unruptured aneurysms than in the ruptured aneurysms. The rupture rate in anterior communicating artery aneurysms was the highest, and it increased with age. A follow-up study was performed on 47 patients with 55 unruptured aneurysms, and only one giant basilar artery aneurysm ruptured during the average follow-up period of 5.2 years. Direct operation was performed on 52 patients with unruptured aneurysms. While the surgical mortality rate was 0%, the morbidity rate was 6% (three of 52 cases), which was not directly related to the patients' age. When considering surgery for unruptured aneurysms, rupture rate of aneurysms at each site is one of the most important factors, especially in elderly patients.     

The significance of unruptured intracranial saccular aneurysms

The authors report the results of a long-term follow-up study of 130 patients with 161 unruptured intracranial saccular aneurysms. Their findings suggest that unruptured saccular aneurysms less than 10 mm in diameter have a very low probability of subsequent rupture. The mean diameter of the aneurysms that subsequently ruptured was 21.3 mm, compared with a diameter of 7.5 mm for aneurysms defined after rupture at the same institution. Part of the explanation for this discrepancy may be that the size of the filling compartment of the aneurysm decreases after rupture. There is also evidence from the present study that intracranial saccular aneurysms develop with increasing age of the patient and stabilize over a relatively short period, if they do not initially rupture, and that the likelihood of subsequent rupture decreases considerably if the initial stabilized size is less than 10 mm in diameter. Consequently, the critical size for aneurysm rupture is likely to be smaller if rupture occurs at the time of or soon after aneurysm formation. There seems to be a substantial difference in potential for growth and rupture between previously ruptured and unruptured aneurysms.     

Size and location of ruptured and unruptured intracranial aneurysms measured by 3-dimensional rotational angiography

OBJECTIVE: The aim of the study was to report about accurate size and location of a consecutive series of ruptured and unruptured aneurysms taking the complex 3-dimensional (3D) anatomy and parent vessel morphology into consideration by using the newly developed 3D rotational angiography (3D-RA). METHODS: One hundred eighteen consecutive patients with 155 saccular intracranial aneurysms were included in the study and received 3D-RA reconstructions for measurement of maximal height and width of the aneurysmal sac. Statistical evaluation compared values for ruptured (n = 83) and unruptured (n = 72) aneurysms. RESULTS: Mean height and width of unruptured aneurysms were 5.7 and 5.7 mm; of ruptured aneurysms, 6.7 and 6.1 mm (not significant, P = .7 for height and P = .9 for width). The majority of ruptured aneurysms, 81.9% and 59%, were smaller than 10 and 7 mm; likewise, 81.9% and 68.1% of unruptured aneurysms were smaller than 10 and 7 mm. The difference in frequency of small (<10/<7 mm) aneurysms between unruptured and ruptured aneurysms was not significant (P = 1.0 and .32, respectively). The majority (69.4%) of small ruptured aneurysms (<7 mm) were located in the anterior circulation. Most ruptured aneurysms were in the size group 4 to 6 mm in height and 2 to 4 mm in width, and a critical threshold size for aneurysm rupture could not be identified. CONCLUSIONS: An automated calibration procedure applied to all images and excellent visualization of aneurysm and parent vessel morphology using 3D-RA allow accurate size measurement of intracranial aneurysms which may be smaller than previously thought. Small aneurysm (<7 mm), also in the anterior circulation, should be carefully evaluated for treatment.     

Current multimodality management of infectious intracranial aneurysms

OBJECTIVE: To implement an algorithm for and assess multimodality (medical, endovascular, and microsurgical) treatment of patients with infectious intracranial aneurysms. METHODS: Twenty patients with 27 infectious aneurysms were treated during a 10-year period. Bacterial endocarditis was the most common cause (65%). Most aneurysms presented with rupture (75%), and the middle cerebral artery was the most common location (70%). RESULTS: Five patients were treated endovascularly, with direct coiling for three patients and parent artery occlusion for two patients. Ten patients (15 aneurysms) were treated surgically, with 6 aneurysms being trapped/resected, 2 trapped/bypassed, 4 clipped, and 3 wrapped. Five patients were treated medically. Treatment-associated neurological morbidity was observed for two patients (10%), and two patients died (10%). Good outcomes were observed for 16 patients (80%). CONCLUSION: Factors that guide management decisions for these patients include aneurysm rupture, hematomas with increased intracranial pressure, and the eloquence of brain tissue supplied by the parent artery. Patients with unruptured infectious aneurysms are initially treated medically, with antibiotics and serial angiography. Patients with ruptured aneurysms that are not associated with hematomas and that do not involve eloquent vascular territory are treated endovascularly. Patients with ruptured aneurysms are treated surgically when there is a hematoma or the risk of ischemic complications in eloquent territory. Therefore, endovascular therapy is the first option for patients in stable condition with ruptured aneurysms; surgical therapy is the first option for patients in unstable condition with ruptured aneurysms and the second option for patients in stable condition who experience failure of endovascular therapy. Medically treated patients with enlarging or dynamic unruptured aneurysms also require direct surgical or endovascular intervention. Favorable patient outcomes can be achieved with this multimodality management.     

Saccular cerebral aneurysms in young adults

BACKGROUND: The formation and rupture of cerebral aneurysms has been controversial. In order to clarify their nature, this study investigates the size and location of ruptured and unruptured aneurysms in young adults and the results of surgery. METHODS: The subjects of this study are 35 patients with ruptured and two with unruptured aneurysms. They range in age from 20 to 39 years. The size and location of their aneurysms were determined by angiographic measure of their maximal inner diameters. Direct surgery was performed on 34 patients with ruptured aneurysms and on one with an unruptured aneurysm. RESULTS: Ruptured aneurysms in young adults increase in number and size as they grow older. In young adults showing no atherosclerosis or hypertension, ruptured aneurysms occurred in locations and with a frequency found in patients with hypertension. In young adults, aneurysms in the internal carotid artery larger than 3.5 mm (Fisher's exact test; p < 0.05) and the anterior communicating artery showed a tendency to rupture. The surgery produced excellent results in young adults with grade I to III by Hunt and Kosnik classification, but extremely poor results for those with grade IV resulting from vasospasm (Fisher's exact test; p < 0.05). CONCLUSION: It is possible that aneurysms found in young adults might in fact have been present from childhood and adolescence, increasing sufficiently in size to rupture in the forties and fifties. Accordingly, while aneurysm formation may be related to fragile arterial walls, aneurysm rupture may be the result of aging factors such as hypertension and atherosclerosis. Even in young adults, vasospasm had an impact on the outcome of surgery.     

Rupture of bacterial intracranial aneurysms following replacement of cardiac valves

Two patients with rheumatic valvular heart disease are discussed in whom a bacterial intracranial aneurysm ruptured in relation to cardiac surgery. Cardiac surgery may predispose such aneurysms to rupture. Cerebral angiography for detecting unruptured aneurysms and surgical excision prior to valve replacement may be indicated in certain patients.     

A proposed parent vessel geometry-based categorization of saccular intracranial aneurysms: computational flow dynamics analysis of the risk factors for lesion rupture

OBJECT: The authors created a simple, broadly applicable classification of saccular intracranial aneurysms into three categories: sidewall (SW), sidewall with branching vessel (SWBV), and endwall (EW) according to the angiographically documented patterns of their parent arteries. Using computational flow dynamics analysis (CFDA) of simple models representing the three aneurysm categories, the authors analyzed geometry-related risk factors such as neck width, parent artery curvature, and angulation of the branching vessels. METHODS: The authors performed CFDAs of 68 aneurysmal geometric formations documented on angiograms that had been obtained in patients with 45 ruptured and 23 unruptured lesions. In successfully studied CFDA cases, the wall shear stress, blood velocity, and pressure maps were examined and correlated with aneurysm rupture points. Statistical analysis of the cases involving aneurysm rupture revealed a statistically significant correlation between aneurysm depth and both neck size (p < 0.0001) and caliber of draining arteries (p < 0.0001). Wider-necked aneurysms or those with wider-caliber draining vessels were found to be high-flow lesions that tended to rupture at larger sizes. Smaller-necked aneurysms or those with smaller-caliber draining vessels were found to be low-flow lesions that tended to rupture at smaller sizes. The incidence of ruptured aneurysms with an aspect ratio (depth/neck) exceeding 1.6 was 100% in the SW and SWBV categories, whereas the incidence was only 28.75% for the EW aneurysms. CONCLUSIONS: The application of standardized categories enables the comparison of results for various aneurysms' geometric formations, thus assisting in their management. The proposed classification system may provide a promising means of understanding the natural history of saccular intracranial aneurysms.     

Simulation of the natural history of cerebral aneurysms based on data from the International Study of Unruptured Intracranial Aneurysms

OBJECT: Despite recent publications of large-scale study data, controversy over the management of unruptured cerebral aneurysms continues. The low rupture rates in the International Study of Unruptured Intracranial Aneurysms (ISUIA) apparently contradicted surgeons' experiences with ruptured aneurysms. In the present study, based on data from the ISUIA, a mathematical model describing the natural history of cerebral aneurysms was developed. With this model, the author aimed to examine the validity of data from the ISUIA and to provide a better treatment guideline for unruptured aneurysms. METHODS: The author made a computer simulation of the natural history of cerebral aneurysms that was used to calculate such figures as the prevalence of unruptured aneurysms, incidence of subarachnoid hemorrhage (SAH), and age and size distribution of both unruptured and ruptured aneurysms. The lifetime lesion rupture probability for individual patients with various ages and aneurysm sizes was also computed, thereby providing a useful index to help patients in the medical decision-making process. The computer model produced a sample of unruptured aneurysms in the general population with a prevalence of 4.2% and a median diameter of 5.8 mm. These unruptured aneurysms--affected by the rupture rate reported in the ISUIA--had a yearly SAH incidence of 19.6 per 100,000 persons. The median diameter of these aneurysms was 9.4 mm. CONCLUSIONS: Findings in the present study validated the results of the ISUIA by showing that the seemingly low rupture rates could explain the statistical data for ruptured aneurysms. With the featured model, the author calculated the lifetime probability of lesion rupture--a useful measure for deciding on the optimal treatment for unruptured aneurysms.     

Endothelial Nitric Oxide Synthase Gene [G894T] polymorphism as a possible risk factor in aneurysmal subarachnoid haemorrhage

Summary Background. The exact aetiology, growth and rupture of intracranial aneurysms is unclear. In this study we investigated a possible association between intracranial aneurysm rupture and polymorphism of the endothelial nitric oxide synthase gene G894T. Methods. Endothelial nitric oxide synthase gene polymorphism of 53 patients with ruptured intracranial aneurysms and 60 control subjects were analysed by the polymerase chain reaction-restriction fragment length polymorphism technique. The genotype distribution and allele frequencies of endothelial nitric oxide synthase gene polymorphism in patients with ruptured intracranial aneurysm and healthy subjects were compared. Findings. The homozygous (TT) genotype frequency was significantly higher in patients with ruptured intracranial aneurysms. It was also found that the presence of eNOS 894TT genotype was significantly associated with the risk of intracranial aneurysm rupture (p < 0.05). Conclusion. Polymorphism in exon 7 of the endothelial nitric oxide synthase gene G894T seems to be a possible risk factor for intracranial aneurysm rupture. Correspondence: ünal ?züm, MD, PhD, Department of Neurosurgery. Cumhuriyet University School of Medicine, 58140 Sivas, Turkey.     

Differences in anatomical distribution,gender, and sidedness between ruptured and unruptured intracranial aneurysms in a defined patient population

Background  

Working with patients with intracranial aneurysms, we have developed a clinical suspicion that there may be differences in the rupture rate of aneurysms depending on the aneurysm’s anatomical location. The aim of the study was to examine the anatomical distribution of ruptured and unruptured intracranial aneurysms in a defined population.     

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.     

Association of endovascular therapy of very small ruptured aneurysms with higher rates of procedure-related rupture

OBJECT: Procedure-related rupture during endovascular therapy of intracranial aneurysms is associated with a mortality rate of more than one third. Previously ruptured aneurysms are a known risk factor for procedure-related rupture. The objective of this study was to evaluate whether very small, ruptured aneurysms are associated with more frequent intraprocedural ruptures. METHODS: This was a retrospective cohort study in which the investigators examined consecutive ruptured aneurysms treated with coil embolization at a single institution. The study was approved by the institutional review board. Very small aneurysms were defined as < or = 3 mm. Procedure-related rupture was defined as contrast extravasation during treatment. Univariate analysis with the Fisher exact test and the Mann-Whitney U test was performed. RESULTS: Between August 1992 and January 2007, 682 aneurysms were selectively treated with coils in 668 patients. Procedure-related rupture occurred in 7 (11.7%) of 60 aneurysms < or = 3 mm, compared with 14 (2.3%) of 622 aneurysms > 3 mm (relative risk 5.2, 95% confidence interval 2.2-12.8; p < 0.001). Among cases with procedure-related rupture, inflation of a compliant balloon was associated with better outcome (Glasgow Outcome Scale Score > or = 4) compared with patients treated without balloon assistance (5 of 5 compared with 7 of 16; p = 0.05). Death resulting from procedure-related rupture occurred in 8 (38%) of 21 patients, and a vegetative state occurred in 1 patient. Clinical outcome was good in the other 12 patients (57%). CONCLUSIONS: Endovascular coil embolization of very small (< or = 3 mm) ruptured cerebral aneurysms is 5 times more likely to result in procedure-related rupture compared with larger aneurysms. Balloon inflation for hemostasis may be associated with better outcome in the event of intraprocedural rupture and merits further study.     

The aspect ratio (dome/neck) of ruptured and unruptured aneurysms

OBJECT: In this retrospective study the authors examined the aspect ratio (AR; the maximum dimension of the dome/width of the neck of an aneurysm) and compared the distribution of this ratio in a group of ruptured and unruptured aneurysms. A similar comparison was performed in relation to the maximum dimension of the aneurysm alone. The authors sought to evaluate the utility of these measures for differentiating ruptured and unruptured aneurysms. METHODS: Measurements were made of 774 aneurysms in 532 patients at three medical centers. One hundred twenty-seven patients harbored only unruptured lesions, 290 only ruptured lesions, and 115 both ruptured and unruptured lesions. Cases were included if angiograms were available for measurement and the status of the individual patient's aneurysm(s) was known. The odds of a lesion falling in the ruptured aneurysm group increased with both the lesion's maximum size and the AR. The odds ratio for rupture rose progressively only for the AR. The distribution curves showed that ruptured aneurysms were larger and had greater ARs. The mean size of unruptured aneurysms was 7 mm and that of ruptured ones was 8 mm; the corresponding mean ARs were 1.8 and 3.4, respectively. The odds of rupture were 20-fold greater when the AR was larger than 3.47 compared with an AR less than or equal to 1.38. Only 7% of ruptured aneurysms had an AR less than 1.38 compared with 45% of unruptured lesions. CONCLUSIONS: The AR is probably a useful index to calculate. A high AR might reasonably influence the decision to treat actively an unruptured aneurysm independent of its maximum size. Prospective studies are warranted.     

Is aspect ratio a reliable predictor of intracranial aneurysm rupture?

OBJECTIVE: This study was undertaken to assess the reliability of the aspect ratio (AR) (i.e., aneurysm depth to aneurysm neck) in predicting aneurysm rupture. It has been shown that the AR is a key factor in predicting intraaneurysmal blood flow and aneurysm rupture. METHODS: Seventy-five patients with subarachnoid hemorrhage and multiple aneurysms were studied. The sizes of the aneurysms and their ARs were determined by examining the angiographic films. By comparing the difference between ruptured and unruptured aneurysms in the same individual, each patient in effect served as his or her own control. Each ruptured aneurysm was confirmed during surgery. RESULTS: There were 75 ruptured and 107 unruptured aneurysms. The mean AR was 2.70 for ruptured aneurysms, compared with 1.8 for unruptured aneurysms. This difference between the ARs was statistically significant (P < 0.001). The difference in aneurysm sizes in the two groups also was significant (P < 0.001). CONCLUSION: AR on its own is as reliable a variable as the size of the aneurysm for predicting aneurysm rupture.     

Management outcomes for ruptured and unruptured aneurysms in the elderly

OBJECTIVE: In a patient older than 70 years, the decision to treat an intracranial aneurysm remains difficult whether it is ruptured or unruptured. We sought to review our institutional risks of treatment of such lesions in the context of the risks of rupture and its associated morbidity and mortality in this age group. METHODS: One hundred twenty-nine consecutive patients aged 70 years or older, who were treated at a single institution for an intracranial aneurysm, were retrospectively reviewed. Forty patients were treated for unruptured aneurysms, and 89 patients presented after subarachnoid hemorrhage. Seven additional patients in this age group who had solely intracavernous lesions, as well as one patient with a dolichoectatic fusiform basilar lesion, were excluded. Management outcomes were assessed using a modification of the Glasgow Outcome Scale, and additional physical and functional disability was assessed using the Barthel index and the Reintegration to Normal Living index. RESULTS: Six-month outcomes for the unruptured group were: excellent, 70%; good, 15%; fair, 5%; poor, 7.5%; and death (2.5%). Outcomes for all patients with ruptured lesions (including those not offered aggressive therapy) were: excellent, 34%; good, 9%; fair, 5.6%; poor, 3.4%; and death, 45%. Long-term follow-up was performed by questionnaire to assess physical and functional disability. Although physical disability (Barthel index) was similar among survivors, the Reintegration to Normal Living index, a global assessment of function, was significantly higher in patients with unruptured aneurysms (84.8 versus 70.1; P = 0.05), which highlights the disabling effects of hemorrhage. CONCLUSION: On the basis of an individual treatment center's management risks, annual aneurysmal rupture rates can be estimated that justify treatment in this difficult patient population. Despite recent controversy regarding aneurysmal hemorrhage rates, we think that symptomatic unruptured aneurysms should be treated and good results can be achieved, even in older patients.