Asymptomatic familial cerebral aneurysms

Screening for Intracranial Aneurysms in Individuals with a Positive First-Degree Family History: A Systematic Review

BACKGROUND

Subarachnoid hemorrhage secondary to rupture of an intracranial aneurysm (IA) is a devastating condition with high morbidity and mortality. Individuals with a positive family history of aneurysmal subarachnoid hemorrhage (aSAH) or IA can have an increased risk for aSAH or IA themselves. Screening is currently recommended in families with ≥2 affected first-degree relatives. We sought to assess the usefulness and cost-effectiveness of IA screening in individuals with a positive first-degree family history, relative to the number of family members affected.

METHODS

We performed a systematic literature search using PubMed and Google Scholar and identified additional studies by reviewing reference lists. Only original studies and review papers were considered. We excluded genetic diseases associated with IA and studies with unclear data concerning the number of first-versus second-degree relatives affected.

RESULTS

This review included 37 articles. Individuals with ≥2 affected first-degree relatives had a greater prevalence of IA (average 13.1% vs. 3% in the general population). Similarly, we found a greater prevalence of IA in individuals with ≥1 affected first-degree relative (average 4.8%, up to 19% in individuals with additional risk factors). The risk of aSAH also was increased in both categories. Recent studies stressed the importance of serial screening over time and suggested that such screening can be cost-effective in persons with only one first-degree relative with IA or aSAH.

CONCLUSIONS

While current guidelines do not recommend screening individuals with ≥1 first-degree relative affected, we found strong arguments in favor of this approach.

Risk factors and treatment approach for subarachnoid hemorrhage in a patient with nine intracranial aneurysms

Introduction. In about one-third of the patients with aneurysmal subarachnoid bleeding, multiple intracranial aneurysms are confirmed. Risk factors such as female gender, smoking, hypertension, and age over 60 tend to be associated with multiple aneurysms. In this paper, we also discuss family predisposition and the treatment approach for multiple cerebral aneurysms. Case outline. Here, we present a case of a female patient, 64-year-old, with spontaneous subarachnoid hemorrhage that had nine intracranial aneurysms. The patient was treated for hypertension for a longer period, excessive smoker, and two of her nearest members of the family died from intracranial bleeding. The patient was fully conscious, without any neurological impairment. Subarachnoid bleeding was diffuse and nor brain-computer tomography finding nor digital subtraction angiography couldn't suggest the source or location of bleeding among nine presented aneurisms. Magnet resonance imaging had to be done, and the T1W fast spin-echo sequence showed a 9 mm large ruptured an aneurysm at the basilar tip, after contrast application, beside others. Three days after insult endovascular embolization was done and two basilar aneurysms were excluded from the circulation, including the one that bled. Conclusion. The patient had the majority of risk factors for multiple intracranial aneurysms. Knowledge of the family predisposition of multiple intracranial aneurysms allowed us to make proper diagnostics of a patient's descendant and reveal a new patient.

Replication of GWAS Loci Revealed an Increased Risk of BET1L and H19 Polymorphisms with Intracranial Aneurysm

A genome-wide association study (GWAS) identified that BET1L rs2280543 at chromosome 11p15.5 was a susceptibility loci of intracranial aneurysm (IA). Long noncoding RNA H19, located in this region, was reported to play a crucial role in the formation of IA. In this study, we aimed to examine whether BET1L rs2280543 and potentially functional polymorphisms in H19 influence the risk of IA. A hospital-based case-control study was performed involving 542 IA patients and 588 age- and gender-matched controls. The BET1L rs2280543 and H19 polymorphisms were genotyped using the TaqMan assay. The BET1L rs2280543 CT, CT/TT genotypes, and T allele were associated with an increased risk of IA (CT vs. CC, adjusted OR = 1.43, 95% CI: 1.08-1.90, P = 0.01; CT/TT vs. CC, adjusted OR = 1.48, 95% CI: 1.12-1.94, P = 0.005; and T vs. C, adjusted OR = 1.44, 95% CI: 1.13-1.83, P = 0.003). Similarly, the H19 rs217727 TT genotype and T allele were associated with an increased risk of IA (TT vs. CC, adjusted OR = 1.90, 95% CI: 1.35-2.67, P < 0.001; T vs. C, adjusted OR = 1.38, 95% CI: 1.16-1.64, P < 0.001). Combined analyses revealed that the rs2280543 CC-rs217727 CT/TT, rs2280543 CT/TT-rs2735971 GG, and rs217727 CT/TT-rs2735971 GG genotypes were related to the risk of IA. Interaction analysis showed that the 3-loci model of rs2280543-rs217727-rs2839698 contributed to an increased risk of IA. These findings suggest that the GWAS-discovered risk loci BET1L rs2280543 may increase IA susceptibility by interacting with lncRNA H19.

Association between angiotensin-converting enzyme insertion/deletion polymorphisms and intracranial aneurysm susceptibility: A meta-analysis

Various studies have evaluated the association between polymorphisms of angiotensin-converting enzyme (ACE) and intracranial aneurysm (IA) risk; however, the results remain inconsistent. The PubMed, Embase, and Wanfang Data databases were systematically searched until January 6th 2016. Case-control studies investigating the association between the ACE polymorphism and IA risk were included. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with the fixed or random-effects model assuming allele, homozygote comparison of codominant, heterozygote comparison of codominant, dominant, and recessive models. Seven studies including 1,074 cases and 1,500 controls were included in the current meta-analysis. The results of the analysis indicated that the ACE polymorphism significantly increased IA risk in the allele, homozygote comparison of codominant and dominant models. According to the further stratified analysis by ethnicity, source of control and sample sizes, a significant association was identified between the ACE variant and IA risk in Asian individuals, hospital-based, or large (>300) subgroups in all of the genetic models, not including the recessive model. Furthermore, no significantly increased risk was indicated in Caucasian individuals, population-based, or small (<300) subgroups in the heterozygote comparison of codominant, dominant and recessive models. The available evidence indicates that the ACE polymorphism is associated with an increased risk of IA, particularly in Asian individuals. However, other factors may impact this association. Further large, well-designed multicenter studies are required to validate the findings from the present study.

Association between functional polymorphisms in the promoter of the miR-143/145 cluster and risk of intracranial aneurysm

MicroRNAs (miRs)-143/145 are involved in various biological processes related to aneurysm formation and are downregulated in patients with intracranial aneurysm (IA). We aimed to determine whether two functional polymorphisms (i.e. rs4705342 and rs4705343) in the promoter of miR-143/145 are related to IA risk. A case-control study was undertaken to examine the association of rs4705342 and rs4705343 with IA risk, including 565 patients with IA and 622 age- and gender-matched controls. rs4705342 was analysed by TaqMan Assay, and rs4705343 was genotyped using polymerase chain reaction-restriction fragment length polymorphism. miR-143/145 expression was quantified using RT-PCR. rs4705342 was associated with a significantly lower risk of IA, with adjusted ORs of 0.74 (95% CI: 0.58–0.95) for TC genotype carriers and 0.74 (95% CI: 0.59–0.94) for TC/CC genotypes carriers. Individuals carrying the rs4705342 C allele had a reduced risk of IA (adjusted OR = 0.82; 95% CI: 0.68–0.98). Haplotype of the two loci of rs4705342 and rs4705343 showed that the CT haplotype carried a lower IA risk and higher miR-143 level. Moreover, the rs4705342 CC/CT genotypes were associated with higher miR-143 levels. Thus, the rs4705342C-rs4705343T haplotype in the promoter of miR-143/145 cluster may be related to IA development.

A Review of the Genetics of Intracranial Berry Aneurysms and Implications for Genetic Counseling

Here we review the current understanding of the genetic architecture of intracranial berry aneurysms (IBA) to aid in the genetic counseling of patients at risk for this condition. The familial subtype of IBA, familial intracranial aneurysms (FIA), is associated with increased frequency of IBA, increased risk of rupture, and increased morbidity and mortality after rupture. Family history is the strongest predictor for the development of IBA. However, a genetic test is not yet available to assess risk within a family. Studies using linkage analysis, genome-wide association, and next-generation sequencing have found several candidate loci and genes associated with disease onset, but have not conclusively implicated a single gene. In addition to family history, a separate or concurrent diagnosis of autosomal dominant polycystic kidney disease is a strong genetic risk factor for IBA formation. We also discuss the relative risk for developing IBA in several Mendelian syndromes including vascular Ehlers-Danlos syndrome, Marfan syndrome, Neurofibromatosis Type I, and Loeys-Dietz syndrome.

Prevalence and Characteristics of Unruptured Cerebral Aneurysms in Ischemic Stroke Patients

BACKGROUND AND PURPOSE

The prevalence of unruptured cerebral aneurysms (UCAs) in ischemic stroke patients is not clearly defined. This study aimed to measure the prevalence and characteristics of UCAs in patients with acute ischemic stroke (AIS) and to compare our findings with those of the general population. In addition, we investigated the factors associated with cerebral aneurysms in AIS patients.

METHODS

We retrospectively reviewed the brain magnetic resonance angiography images of 955 patients with AIS and 2,118 controls who had received a brain magnetic resonance angiography as part of a health check-up. We investigated the prevalence, size, location, and risk factors of the subjects in the context of UCAs.

RESULTS

UCAs were found in 74 patients with AIS (7.7%) and in 79 who received a health check-up (3.7%). The prevalence of UCAs was significantly higher in the AIS group than in the health check-up group (odds ratio 2.17, 95% confidence interval 1.56-3.01). The mean aneurysm diameter was larger in the AIS group than in the health check-up group (3.75 mm vs. 3.02 mm, P=0.009). UCAs were primarily located in the internal carotid artery in both groups, and aneurysms in the middle cerebral artery were particularly common in the AIS group. According to multivariate analysis, hypertension alone was associated with an increased prevalence of UCAs in stroke patients.

CONCLUSIONS

This study identified a higher prevalence and larger size of UCAs in AIS patients than in the general population. Hypertension was an independent risk factor of UCA in AIS.

Neuroimaging in the Evaluation of Patients with Non-Acute Headache

Available studies offer only limited guidance on neuroimaging of non-acute headache patients. The aim of this study was to estimate the frequency of significant intracranial lesions in patients with headache and to determine the clinical variables helpful in identifying patients with intracranial lesions. All patients aged ≥l 15 years attending the Neurology Clinic with non-acute headache were included in the study and followed prospectively. Every patient was investigated by neuroimaging studies, either computed tomography or magnetic resonance imaging. Neuroimaging results were classified as ‘significant abnormalities’, ‘nonsignificant abnormalities’ or ‘normal’. Significant abnormalities included neoplastic disease, hydrocephalus, vascular malformations, Chiari malformation, large arachnoid cysts, intracranial haemorrhage, and acute cerebral infarcts. Consecutive patients ( n = 1876; 1243 women and 633 men) were included. Their mean age was 38 years (range 15-95 years). Neuroimaging studies detected significant lesions in 22 patients [1.2%, 95% confidence interval (CI) 0.7, 1.8]. The rate of significant intracranial abnormalities in patients with headache and normal neurological examination was 0.9% (95% CI 0.5, 1.4). The only clinical variable associated with a higher probability of intracranial abnormalities was neurological examination. The proportion of patients with headache and intracranial lesions is relatively small, but neither neurological examination nor the features in the clinical history permit us to rule out such abnormalities.

CTA Characteristics of the Circle of Willis and Intracranial Aneurysm in a Chinese Crowd with Family History of Stroke

BACKGROUND AND PURPOSE

The vascular morphology in crowd with family history of stroke remains unclear. The present study clarified the characteristics of the intracranial vascular CoW and prevalence of intracranial aneurysms in subjects with family history of stroke.

METHODS

A stratified cluster, random sampling method was used for subjects with family history of stroke among rural residents in Jixian, Tianjin, China. All the subjects underwent a physical examination, head computed tomography (CT) scan, and cephalic and cervical computed tomography angiography (CTA) scan. Anatomic variations in the Circle of Willis and cerebrovascular disease in this population were analyzed.

RESULTS

In the crowd with similar living environment, stable genetic background, and family history of stroke and without obvious nerve function impairment (1) hypoplasia or absence of A1 segment was significantly different in gender (male versus female: 9.8% versus 18.8%, p = 0.031), especially the right-side A1 (male versus female: 5.9% versus 16.4%, p = 0.004). (2) Hypoplasia or absence of bilateral posterior communicating arteries was more common in men than women (58.2% versus 45.3%, p = 0.032). Unilateral fetal posterior cerebral artery was observed more often in women than men (17.2% versus 8.5%, p = 0.028). (3) The percentage of subjects with incomplete CoW did not increase significantly with age. Compared to healthy Chinese people, the crowd had a higher percentage of incomplete CoW (p < 0.001). (4) No obvious correlation between risk factors and CoW was found. (5) The prevalence of aneurysm was 10.3% in the special crowd.

CONCLUSIONS

The certain variations of CoW showed significant relation to gender, but not to age in people with family history of stroke. The incomplete circle may be a dangerous factor that is independent of common risk factors for stroke and tend to lead to cerebral ischemia in the crowd with family history of stroke. The prevalence of intracranial aneurysm is comparatively high in the present subjects compared to other people.

A Potential Polymorphism in the Promoter of Let-7 is Associated With an Increased Risk of Intracranial Aneurysm: A Case-Control Study

Let-7 family plays a key role in the progression of atherosclerosis and intracranial aneurysm (IA). We hypothesized that rs10877887 and rs13293512 polymorphisms in the promoters of let-7 family may be associated with the susceptibility of IA. We genotyped the 2 single nucleotide polymorphisms (SNPs) in 305 patients with IA and 401 healthy controls. The rs10877887 was analyzed using a polymerase chain reaction-restriction fragment length polymorphism assay, and the rs13293512 was analyzed using a TaqMan SNP genotyping method. The relative expression of let-7 family was measured in plasma of cases and controls using real-time PCR. We found that the rs13293512CT genotype was associated with a significantly increased risk of developing IA in a heterozygote comparison (adjusted OR = 1.43, 95% CI, 1.00-2.05, P = 0.048) and dominant comparison (adjusted OR = 1.44, 95% CI, 1.02-2.03, P = 0.04). Combined analysis showed that the rs10877887TT and rs13293512CC/CT genotypes had a significantly increased risk of IA (OR = 1.67, 95% CI, 1.04-2.68, P = 0.03). Moreover, the levels of let-7a, let-7d, and let-7f were downregulated in IA patients, and patients with the rs13293512CC/CT genotypes had a lower level of let-7a than those with rs13293512TT genotype (P = 0.03). These findings indicate that the rs13293512CC/CT is a risk factor for the development of IA, possibly because of the genotypes resulting in a lower level of let-7a.

Subarachnoid hemorrhage in Kashmir: Causes, risk factors, and outcome

Context:

Kashmir, a snow bound and mountain locked valley, is populated by about 7 million ethnic and non-migratory Kashmiris who have specific dietary and social habits than rest of the world. The neurological disorders are common in Kashmiri population.

Aims:

To study the prevalence and outcome of spontaneous intracranial subarachnoid hemorrhage (SAH) in Kashmir compared withother parts of the world.

Settings and Design:

A retrospective and hospital based study from 1982 to 2010 in the single and only Neurosurgical Centre of the State of Jammu and Kashmir.

Materials and Methods:

A hospital based study, in which, information concerning all Kashmiri patients was collected from the case sheets, patient files, discharge certificates, death certificates, and telephonic conversations with the help of Medical Records Department and Central Admission Register of Sher–i-Kashmir Institute of Medical Sciences, Kashmir India.

Statistical Analysis:

Analysis of variance and students T-test were used at occasions.

Results:

Incidence of SAH in Kashmiris is about 13/100,000 persons per year. SAH comprises 31.02% of total strokes and aneurysmal ruptures are cause of 54.35% SAHs. The female suffers 1.78 times more than the male. Total mortality of 36.60% was recorded against a good recovery of 14.99%. The familial SAHs and multiple aneurysms were also common. Intra-operative finding of larger aneurysmal size than recorded on pre-operative computed tomography (CT) angiogram of same patients was noteworthy. In 493 patients of SAH, the angiography revealed 705 aneurysms.

Conclusion:

Spontaneous intracranial subarachnoid hemorrhage, due to aneurysmal rupture, is common in Kashmir, with worst outcome. Food habits like “salt-tea twice a day”, group-smoking of wet tobacco like “Jejeer”, winter season, female gender, hypertension, and inhalation of “Kangri” smoke are special risk factorsof SAH, in Kashmiris. The plain CT brain and CT angiography are best diagnostic tools. The preventive measures for aneurysmal formation and rupture seems most promising management of future. The detachable endovascular aneurysmal occupying video assisted micro-camera capsules or plugs may be future treatment.

Management of aneurysmal subarachnoid hemorrhage

OBJECTIVE

Acute aneurysmal subarachnoid hemorrhage (SAH) is a complex multifaceted disorder that plays out over days to weeks. Many patients with SAH are seriously ill and require a prolonged intensive care unit stay. Cardiopulmonary complications are common. The management of patients with SAH focuses on the anticipation, prevention, and management of these secondary complications.

DATA SOURCES

Source data were obtained from a PubMed search of the medical literature.

DATA SYNTHESIS AND CONCLUSION

The rupture of an intracranial aneurysm is a sudden devastating event with immediate neurologic and cardiac consequences that require stabilization to allow for early diagnostic angiography. Early complications include rebleeding, hydrocephalus, and seizures. Early repair of the aneurysm (within 1-3 days) should take place by surgical or endovascular means. During the first 1-2 weeks after hemorrhage, patients are at risk of delayed ischemic deficits due to vasospasm, autoregulatory failure, and intravascular volume contraction. Delayed ischemia is treated with combinations of volume expansion, induced hypertension, augmentation of cardiac output, angioplasty, and intra-arterial vasodilators. SAH is a complex disease with a prolonged course that can be particularly challenging and rewarding to the intensivist.

Sequencing of TGF-beta pathway genes in familial cases of intracranial aneurysm

BACKGROUND AND PURPOSE

Familial aggregation of intracranial aneurysms (IA) strongly suggests a genetic contribution to pathogenesis. However, genetic risk factors have yet to be defined. For families affected by aortic aneurysms, specific gene variants have been identified, many affecting the receptors to transforming growth factor-beta (TGF-beta). In recent work, we found that aortic and intracranial aneurysms may share a common genetic basis in some families. We hypothesized, therefore, that mutations in TGF-beta receptors might also play a role in IA pathogenesis.

METHODS

To identify genetic variants in TGF-beta and its receptors, TGFB1, TGFBR1, TGFBR2, ACVR1, TGFBR3, and ENG were directly sequenced in 44 unrelated patients with familial IA. Novel variants were confirmed by restriction digestion analyses, and allele frequencies were analyzed in cases versus individuals without known intracranial disease. Similarly, allele frequencies of a subset of known SNPs in each gene were also analyzed for association with IA.

RESULTS

No mutations were found in TGFB1, TGFBR1, TGFBR2, or ACVR1. Novel variants identified in ENG (p.A60E) and TGFBR3 (p.W112R) were not detected in at least 892 reference chromosomes. ENG p.A60E showed significant association with familial IA in case-control studies (P=0.0080). No association with IA could be found for any of the known polymorphisms tested.

CONCLUSIONS

Mutations in TGF-beta receptor genes are not a major cause of IA. However, we identified rare variants in ENG and TGFBR3 that may be important for IA pathogenesis in a subset of families.

Genomewide Linkage in a Large Caucasian Family Maps a New Locus for Intracranial Aneurysms to Chromosome 13q

Background and Purpose— Familial aggregation of intracranial aneurysms (IAs) indicates a genetic role in the pathogenesis of this disease. Despite a number of reported susceptibility loci, no disease-causing gene variants have been identified. In this study, we used a parametric genomewide linkage approach to search for new IA susceptibility loci in a large Caucasian family.

Methods— The affection status of family members with clinical signs of IA was confirmed with medical records or through radiological or surgical examinations. All other relatives were screened using MR angiography. Genomewide linkage analysis was performed on 35 subjects using approximately 250 000 single nucleotide polymorphic markers.

Results— Ten individuals had an IA. Linkage analysis using a dominant model showed significant linkage to a 7-cM region in 13q14.12–21.1 with a maximum logarithm of odds score of 4.56.

Conclusion— A new IA susceptibility locus on 13q was identified, adding to the number of IA loci already reported. Given that no coding variants have been reported to date, it is possible that alternative genetic variants such as regulatory elements or copy number variation are important in IA pathogenesis. We are proceeding with attempts to identify such variants in our locus.

TUMOR NECROSIS FACTOR-α GENE AND CEREBRAL ANEURYSMS

OBJECTIVE

The pathogenesis of intracranial aneurysms is still uncertain. In addition to atherosclerosis, immunological factors may play a role in the disease. Recent studies have suggested that tumor necrosis factor-alpha (TNF-alpha), one of the main proinflammatory cytokines, may play a key role in the formation and rupture of cerebral aneurysms. The purpose of this study is to evaluate the association of a functionally active polymorphism (-308 G<A) in the TNF-alpha gene with the risk and the clinical features of aneurysmal subarachnoid hemorrhage.

METHODS

A total of 171 consecutive aneurysmal subarachnoid hemorrhage patients and 144 healthy controls were involved in the study. Computed tomographic scan findings were assessed by Fisher grade; clinical neurological assessment was performed using the Hunt and Hess grading system. Patients and controls were genotyped for the-308 biallelic (G<A) polymorphism of the TNF-alpha gene.

RESULTS

The TNF-alpha G allele was significantly more frequent in patients than in controls (chi2 = 5.59; P = 0.0181) and homozygosity for the G allele, compared with remaining genotypes, was associated with a significantly increased risk of aneurysmal subarachnoid hemorrhage (odds ratio = 2.20; 95% confidence interval = 1.29<odds ratio<3.75). Allelic and genotypic frequencies of the examined polymorphism were not significantly different in disease subgroups. The different TNF-alpha genotypes do not seem to significantly modify the main clinical features of the disease.

CONCLUSION

Our data suggests that the TNF-alpha gene or a linked locus significantly modulates the risk for aneurysmal subarachnoid hemorrhage. Additional studies in different populations are warranted to confirm our findings.

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.

[Endovascular therapy for intracranial aneurysms]

During the past 5 to 10 years, therapy for aneurysms has seen dramatic changes. In some centers they happened before the ISAT study, in others afterward. Endovascular treatment is now the method of choice for intracranial aneurysms whenever possible. Large centers are using it for 70-80% of aneurysms. Due to constant development of new interventional materials, even wide-necked aneurysms in practically all localizations can be treated today with very dependable results. The remaining aneurysms are quite difficult to treat and represent a great neurosurgical challenge. Despite all the technical improvements, closure is still not the most difficult element of the therapeutic procedure. This role is played by the subarachnoidal hemorrhage, which still is decisive for patient outcome. All related disciplines are urgently called upon to solve the unresolved problems as quickly and efficiently as possible through determined research.

Risk Factors for Growth of Unruptured Intracranial Aneurysms: Follow-up Study by Serial 0.5–T Magnetic Resonance Angiography

OBJECTIVE:

The independent risk factors for aneurysm growth were retrospectively investigated in 130 patients with unruptured aneurysms who were followed up by 0.5–T serial magnetic resonance angiography with stereoscopic images.

METHODS:

Age, sex, site of aneurysm, size of aneurysm, multiplicity of aneurysms, type of circle of Willis, length of follow-up period, cerebrovascular event, hypertension, diabetes, hyperlipidemia, smoking habit, and family history of subarachnoid hemorrhage were investigated using multiple logistic analysis.

RESULTS:

Fourteen patients (16 aneurysms) among the 130 patients (159 aneurysms) showed aneurysm growth (10.8%) during follow-up of 10 to 69 months (mean 29.3 ± 10.5 mo). Multiple logistic analysis disclosed that location on the middle cerebral artery (odds ratio [OR] 0.08, P &lt; 0.01), multiplicity of aneurysms (OR 68.5, P &lt; 0.01), aneurysm size of 5 mm or larger (OR 1.17, P = 0.05), and family history of subarachnoid hemorrhage (OR 10.9, P &lt; 0.01) were independent risk factors.

CONCLUSION:

Location on the middle cerebral artery, multiplicity, aneurysm size of 5 mm or larger, and family history of subarachnoid hemorrhage are independent risk factors for aneurysm growth. These results may help to determine the treatment choice for unruptured aneurysms.

The genetics of intracranial aneurysms

The rupture of an intracranial aneurysm (IA) leads to a subarachnoid hemorrhage, a sudden onset disease that can lead to severe disability and death. Several risk factors such as smoking, hypertension and excessive alcohol intake are associated with subarachnoid hemorrhage. IAs, ruptured or unruptured, can be treated either surgically via a craniotomy (through an opening in the skull) or endovascularly by placing coils through a catheter in the femoral artery. Even though the etiology of IA formation is mostly unknown, several studies support a certain role of genetic factors. In reports so far, genome-wide linkage studies suggest several susceptibility loci that may contain one or more predisposing genes. Studies of several candidate genes report association with IAs. To date, no single gene has been identified as responsible for IA formation or rupture. The identification of susceptible genes may lead to the understanding of the mechanism of formation and rupture and possibly lead to the development of a pharmacological therapy.

A haplotype spanning two genes, ELN and LIMK1, decreases their transcripts and confers susceptibility to intracranial aneurysms

The rupture of an intracranial aneurysm (IA) results in subarachnoid hemorrhage, a catastrophic neurological condition with high morbidity and mortality. Following-up on our previous genome-wide linkage study in Japanese population, we extensively analyzed a 4.6 Mb linkage region around D7S2472 on 7q11 by genotyping 168 single nucleotide polymorphisms (SNPs). SNP association and window scan haplotype-based association studies revealed a susceptibility locus for IA on a single LD block covering the 3'-untranslated region (3'-UTR) of ELN and the entire region of LIMK1. An association study with 404 IA patients and 458 non-IA controls revealed that the ELN 3'-UTR G(+659)C SNP has the strongest association to IA (P=0.000002) and constitutes a tag-SNP for an at-risk haplotype, which contains two functional SNPs, the ELN 3'-UTR (+502) A insertion and the LIMK1 promoter C(-187)T SNP. These allelic and haplotype-based associations were confirmed in a Korean population. Ex vivo and in vitro analyses demonstrate that the functional impact of both SNPs is the decrease of transcript levels, either through accelerated ELN mRNA degradation or through decreased LIMK1 promoter activity. Elastin and LIMK1 protein are involved in the same actin depolymerization signaling pathway; therefore, these lines of evidence suggest a combined effect of the SNPs in the at-risk haplotype possibly by weakening the vascular wall and promoting the development of IA.

Anévrismes intracrâniens non rompus : que proposer ?

Intracranial unruptured aneurysm (ICUA) has become a common condition for patient consultation. The mortality rate after fissuration is estimated to be between 52% and 85.7%. The final therapeutic decision results from a balance between the risk of rupture and risks related to the aneurysmal exclusion. Analysis of the risk of rupture risk enables a classification of risk factors. Depending on the circumstances of diagnosis, we considered the ICUA at high risk of rupture for incidental ICUA larger than 7 mm and in the event of associated aneurysms. Classifying by morphologic features, high-risk ICUA were located in the vertebrobasilar system (RR: 4.4; 95%CI: 2.7-6.8), those with a size between 7 and 12 mm (RR: 3.3; 95%CO: 1.3-8.2), larger than 12 mm (RR: 17; 95%CI: 8-36.1), those that were multilobular or a larger size and those ones with a index P/L superior to 3.4 (risk x20). Familial ICUA would expose to a major rupture risk (2 to 7 times sporadic ICUA). Some systemic factors were related to ICUA rupture: arterial hypertension (RR: 1.46; 95%CI: 1.01-2.11) and smoking addiction (RR: 3.04; 95%CI: 1.21-7.66). After microsurgical exclusion, the morbidity and mortality rates were 10% and 2% respectively. Some microsurgical morbidity factors were identified: age (32%>65 years), size (14%>15 mm), vertebrobasilar location and temporary occlusion. The rupture incidence after microsurgical exclusion was estimated 0.26%/year. After endovascular exclusion, the morbidity and mortality rates were 8% and 1% respectively. The complete exclusion rate varied between 47% and 67%. The rupture risk was estimated at 0.9%/year. Treatment recommendations were classified into 3 categories.

Subarachnoid hemorrhage: neurointensive care and aneurysm repair

Aneurysmal subarachnoid hemorrhage (SAH) is often a neurologic catastrophe. Diagnosing SAH can be challenging, and treatment is complex, sophisticated, multidisciplinary, and rarely routine. This review emphasizes treatment in the intensive care unit, surgical and endovascular therapeutic options, and the current state of treatment of major complications such as cerebral vasospasm, acute hydrocephalus, and rebleeding. Outcome assessment in survivors of SAH and controversies in screening of family members are discussed.

Automated computerized scheme for detection of unruptured intracranial aneurysms in three-dimensional magnetic resonance angiography

RATIONALE AND OBJECTIVES

A computerized scheme for automated detection of unruptured intracranial aneurysms in magnetic resonance angiography was developed based on the use of a three-dimensional selective enhancement filter for dots (aneurysms).

MATERIALS AND METHODS

Twenty-nine cases with 36 unruptured aneurysms (diameter, 3 to 26 mm; mean, 6.6 mm) and 31 non-aneurysm cases were used in this study. The isotropic 3-dimensional magnetic resonance angiography images with 400 x 400 x 128 voxels (voxel size, 0.5 mm) were processed by use of the selective enhancement filter. The initial candidates were identified by use of a multiple gray-level thresholding technique on the dot-enhanced images and a region-growing technique with monitoring some image features. All candidates were classified into four types of candidates according to the size and local structures based on the effective diameter and skeleton image of each candidate (ie, large candidates and three types of small candidates including short-branch type, single-vessel type, and bifurcation type). In each group, a number of false-positives were removed by use of different rules on localized image features related to gray levels and morphology. Linear discriminant analysis was used for further removal of false-positives.

RESULTS

With this computer-aided diagnostic scheme, all of 36 aneurysms were correctly detected with 2.4 false-positives per patient based on a leave-one-out-by-patient test method.

CONCLUSION

This computer-aided diagnostic system would be useful in assisting radiologists for the detection of intracranial aneurysms in magnetic resonance angiography.

Identical cerebral aneurysms in siblings: report of two families

Two pairs of sisters with identical cerebral aneurysms are reported. In the first family, a sibship of three, the two female members presented with subarachnoid haemorrhages from identical, left internal carotid artery bifurcation aneurysms. The subarachnoid haemorrhage occurred in one of the sisters at the age of 20 and at the age of 50 in the other. The remaining healthy sibling, a 40-year-old male, underwent elective cerebral angiography, which was normal. The other sibship, two 48-year-old female identical twins, had identical right middle cerebral artery aneurysms. The first twin became symptomatic after subarachnoid haemorrhage. The aneurysm in her identical twin was identified by screening angiography. There were no verified subarachnoid haemorrhages among the parents and grandparents in either family. No systemic anomalies were identified and collagen type 3 deficiencies were excluded. The identical location of these familial aneurysms, particularly in view of the relatively rare location in the first family, suggests that local factors in the developing vascular tree may play a role in the pathogenesis of saccular aneurysms in addition to systemic anomalies affecting the general structure of cerebral vascular walls.

Anticipation in familial intracranial aneurysms in consecutive generations

Intracranial aneurysms (IA) are the major cause of subarachnoid haemorrhages (SAH). A positive family history for SAH is reported in 5-10% of the patients. The mode of inheritance is not unambiguously established; both autosomal dominant and recessive modes have been reported. In sporadic as well as in familial SAH, approximately 60% of the SAH patients are female. Recently, anticipation has been described in familial SAH. Since up to 15% of the SAHs are not caused by an IA, we have analysed anticipation, sex ratio and mode of inheritance only in families with patients with a proven IA in two consecutive generations. A total of 10 families were studied in which at least two persons in consecutive generations were affected by SAH, a symptomatic IA (SIA) or a presymptomatic IA (PIA). We also analysed published data from families with a proven IA in two consecutive generations on age of SIA onset and sex ratios among affected family members (both SIA and PIA). The age of SIA onset in the parental generation (mean 55.5 years) differed significantly from the age of onset in their children (mean 32.4 years). In the parental generation 11 men and 37 women were affected (both SIA and PIA), in the consecutive generation these numbers were 28 men and 32 women. There is a significant difference in sex ratio of affected family members when the generations are compared (P<0.02). No family could be found in which three consecutive generations were affected by an IA (SIA or PIA).

Molecular pathogenesis of subarachnoid haemorrhage

Subarachnoid haemorrhage (SAH) results from leakage of blood into the subarachnoid space and carries high morbidity and mortality. However, there is limited understanding to date, of the risk factors, cellular, intermediate biochemical and genetic traits predisposing to SAH. Nevertheless, in conjunction with improved methods of diagnostic imaging and less invasive approaches to preventing aneurysmal rupture, there may be utility in gaining a better understanding of the pathogenesis and in identifying pre-disease markers. Additionally, it is not impossible that drugs of value (e.g. matrix or endothelial modifiers) could become available. Several different clinical subtypes can be recognised, distinguished by arterial or venous involvement, presence of unruptured arterial aneurysms, and apparently "sporadic" and "familial" occurrences. Epidemiological risk factors include alcohol consumption and smoking: hypertension is a risk factor for rupture. About 10% seem to reflect strong family history and this subset may be particularly illuminating with respect to the molecular pathogenesis. Haemodynamic stress and poor vascular structure may be the main mechanisms of pathogenesis. The epidemiological and statistical evidence for familial megaphenic genes and modifier genes is reviewed. This review focuses on the pathogenesis, as opposed to inflammatory response to SAH. It sets in context the roles of specific genes and their protein products, such as polycystin (PKD1), fibrillin (FBN1), collagen III (COL3A1), elastin (ELN), collagen IV, protease inhibitor or alpha1-antitrypsin (PI) and proteases. These considerations illustrate the shortfalls in current knowledge, the needs of future biochemical and cellular research and their potential implications for future prevention of this often fatal condition.

Screening for intracranial aneurysms in autosomal dominant polycystic kidney disease. Review Article

Screening patients with autosomal dominant polycystic kidney disease (ADPKD) for asymptomatic intracranial aneurysms has been proposed as a method of reducing the morbidity and mortality associated with aneurysm rupture. However, recent studies have shown lower spontaneous rupture rates of small aneurysms and higher risks of significant complications with interventions than previously reported. Risk-benefit analysis has not demonstrated any benefit of screening ADPKD patients without a history of subarachnoid haemorrhage (SAH) for intracranial aneurysms, and has suggested that screening might cause harm.

Familial intracranial aneurysms: an analysis of 346 multiplex Finnish families

BACKGROUND AND PURPOSE

Genetic risk factors are considered important in the development, growth, and rupture of intracranial aneurysms; however, few have been identified. We analyzed intracranial aneurysm families with at least 2 affected persons and determined relationships between affected persons and assessed the inheritance patterns of aneurysms.

METHODS

Families with > or =2 members with verified diagnoses of intracranial aneurysms were recruited from Kuopio and Helsinki, Finland. Families with a diagnosis of other heritable disorders that have associated intracranial aneurysms, such as autosomal dominant polycystic kidney disease, were excluded.

RESULTS

We identified 346 Finnish multiplex families with 160 (46.2%) male and 186 (53.8%) female index cases. There were a total of 937 aneurysm cases, with an average of 2.7 cases per family. The majority of the families had only 2 affected relatives (n=206; 59.5%), although there were families with up to 6 (n=10), 7 (n=1), 8 (n=1), or 10 (n=2) affected persons. The affected relatives of the index cases included 108 sisters, 116 brothers, 105 parents, 30 children, 15 grandparents, 102 aunts or uncles, and 64 cousins. Of the 937 affected persons, 569 (60.7%) were alive and available for genetic analysis. Inheritance patterns consistent with autosomal recessiveness were observed in 198 (57.2%), autosomal dominance in 126 (36.4%), and autosomal dominance with incomplete penetrance in 19 (5.5%) of the families.

CONCLUSIONS

The collection is the most extensive published to date and extends previous observations of familial aggregation that are consistent with a major gene effect.

Absence of linkage of familial intracranial aneurysms to 7q11 in highly aggregated Japanese families

BACKGROUND AND PURPOSE

We sought to test the linkage of familial intracranial aneurysms (FIAs) to the ELN (elastin) locus in chromosome 7q11 reported previously.

METHODS

Intracranial aneurysm (IA) probands were searched from patient records or neurosurgeons' recalls in collaborating hospitals. Members of the participating probands' families who had unknown affection status were screened by MR angiography and diagnosed by digital subtraction angiography. Inclusion criteria of families for genetic analyses were as follows: at least 3 alive affected members or 2 alive affected members with at least 1 unaffected member (>or=60 years). Linkage to the ELN locus was tested with the use of GENEHUNTER by parametric and nonparametric methods. To exclude false-negatives in the linkage analysis, the lowest 5% limits of logarithms of the odds (LOD) and nonparametric LOD (NPL) scores for individual families and for the total set of families were simulated on assumption that the ELN locus is linked to FIAs.

RESULTS

Questionnaires were sent to 885 patients, and 563 responded. Seventy-nine probands were positive for family history. One hundred thirty-four family members of unknown affection status were screened. A total of 14 families with 64 members met the criteria. Linkage to the ELN locus was discarded in 11 families and was inconclusive for 3 families. The total LOD and total NPL scores for 14 families were -8.04 and -0.643, respectively. Our conclusion did not change even when the values of penetrance were changed or only affected members were analyzed.

CONCLUSIONS

The majority of aggregated IA Japanese families may not have a genetic linkage to chromosome 7q11.

Family history and risk of subarachnoid hemorrhage: a case-control study in Nagoya, Japan

BACKGROUND AND PURPOSE

We sought to examine the relation between a family history of subarachnoid hemorrhage (SAH) and the risk of SAH by using a case-control study.

METHODS

Case subjects consisted of a consecutive series of 195 patients with spontaneous SAH, aged 30 to 79 years, with aneurysms confirmed by angiography and/or CT scan. Hospital and community control subjects were identified and matched to each case by sex and age (+/-2 years). Multiple conditional logistic regression was used to calculate the odds ratio (OR) and 95% interval (CI) adjusted for potential confounders.

RESULTS

Having a family member with SAH was significantly associated with an increased risk of SAH (OR, 4.0, 95% CI, 2.0 to 8.0), after adjusting for potential confounders. The risk for a positive family history of SAH was similar for men and women and was inversely related to the SAH patient's age. A maternal positive SAH history (OR, 5.4; 95% CI, 1.8 to 16.0) posed a much greater risk than a paternal positive history (OR, 3.2, 95% CI, 1.1 to 13.4).

CONCLUSIONS

A positive family history of SAH was significantly and strongly associated with the risk of SAH. To prevent the onset of SAH at a younger age, much more attention should be given to individuals with any family member (first-degree relatives) suffering SAH episodes.

Aneurysm observation versus intervention: a literature review

Aneurysmal subarachnoid hemorrhage (SAH) is a devastating illness that affects persons at the peaks of their lives. The 1990s witnessed rapid growth in noninvasive vascular imaging technologies, which allowed safe diagnosis of unruptured saccular intracranial aneurysms. Presently, it is unclear who will benefit from screening. Mass screening is neither feasible nor cost-effective. The current literature suggests that persons in a family with two or more relatives with a history of SAH are most likely to benefit from screening. Individuals with a history of SAH, with aneurysms greater than 10 mm in diameter or with symptomatic aneurysms are clearly at increased risk for SAH. These aneurysms should be treated, though the method of treatment remains open to question. Treatment of older patients or those with smaller aneurysms has been modeled by decision analysis, but has yet to be verified in a prospective clinical trial. Future directions for aneurysm management are explored.

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.

Computed tomography scan of the head in patients with migraine or tension-type headache

A retrospective study was performed in order to evaluate the frequency of abnormalities found by computed tomography (CT) scan of the head in 78 patients with migraine or tension-type headache. In the present study CT scan was normal in 61.5% of the patients with migraine or tension-type headache. A number of abnormalities were encountered in more than one third of the patients studied, including inflammatory sinus disease (19.2%), cysticercosis (3.9%), unruptuted cerebral aneurysm (2.6%), basilar impression (2.6%), intracranial lipoma (2.6%), arachnoid cyst (2.6%), empty sella (2.6%), intracranial neoplasm (2.6%), and others (2.6%). None of these lesions were symptomatic or responsible by the headache picture, therefore, considered incidental findings. In conclusion, the fortuitous encounter of some abnormalities on CT scan of the head is often higher than what we could predict in patients suffering migraine or tension-type headache. We briefly discuss clinical, epidemiologic, and practical management of some of the abnormalities detected by CT scan as well as the indication to request a neuroimaging investigation.

Endovascular management of unruptured intracranial aneurysms: does outcome justify treatment?

OBJECTIVE

The appropriate management of unruptured intracranial aneurysms depends on a complete understanding of their natural history and on the risks and efficacy of treatment options. There is little current data on the risks of endovascular therapy for these aneurysms. The aim of this study was to assess outcome of endovascular treatment of unruptured intracranial aneurysms.

METHOD

A retrospective analysis was performed on all unruptured aneurysms treated by Guglielmi detachable (GD) coils at this institution from 1994 to 2000.

RESULTS

Seventy three unruptured aneurysms were treated in 62 patients. There were 52 female and 10 male patients, with a median age of 55.7 years. Clinical background was: subarachnoid haemorrhage due to rupture of an additional aneurysm (40), headache (4), third nerve palsy (four), familial (four), and incidental (10). There were 14 technical failures with no clinical sequelae. Four procedural complications occurred (5.5%, 95% confidence interval (95% CI) 0.3% to 10.9%). One patient had temporary clinical sequelae (1.4%, 95% CI 0% to 2.7%); 79% of treated aneurysms had stable occlusions at follow up, 10.5% showed improved occlusion grade, 10.5% showed some recurrence, and three patients have required retreatment. Follow up modified Glasgow outcome scores were grade 1, 71%; grade 2, 18%; grade 3, 3%; grade 4, 3%. There were no deaths or haemorrhages during the follow up period. Two patients died as a result of complications from subarachnoid haemorrhage.

CONCLUSION

The endovascular treatment of patients with unruptured aneurysms is safe with few clinical or procedural complications. Poor outcomes were only seen in those patients who presented with subarachnoid haemorrhage due to rupture of an aneurysm at another site.

Characteristics of brain arteriovenous malformations with coexisting aneurysms: a comparison of two referral centers

BACKGROUND

Patients harboring a brain arteriovenous malformation (BAVM) often have coexisting arterial aneurysms. Experts have argued about the clinical significance of these aneurysms, which may be important for risk stratification in patient management and clinical trials. We studied the association between coexisting aneurysms and initial presentation with intracranial hemorrhage (ICH) in patients with BAVM evaluated at two tertiary-care centers.

METHODS

Demographic and clinical data were collected from a prospective series of patients evaluated for BAVM at the University of California, San Francisco (UCSF; n=82), and Columbia-Presbyterian Medical Center, New York (CPMC; n=254). Using multivariate logistic regression, we examined the independent association between ICH presentation and the presence of a coexisting aneurysm, and compared the association at the two hospitals.

RESULTS

Aneurysms were associated with 28 BAVMs at UCSF (34%) and 74 at CPMC (29%; P=0.39). Initial presentation with ICH was associated with the presence of a coexisting aneurysm at CPMC (odds ratio 1.8, 95% confidence interval 1.0 to 3.0, P=0.044). The opposite trend was observed at UCSF (odds ratio 0.4, 95% confidence interval 0.2 to 1.1, P=0.085). We observed an interaction by site involving the association between ICH presentation and aneurysm (P=0.016).

CONCLUSION

Although many BAVM characteristics were similar at the referral centers studied, the association between initial presentation with ICH and coexisting aneurysms was not. This heterogeneity between populations undermines the validity of inferences on the role of aneurysms from any single referral series, and emphasizes the complexity in creating BAVM risk-stratification models that incorporate aneurysms.

Treatment strategy for patients with unruptured intracranial aneurysms

The increased sensitivity of neuroimaging techniques has enabled the more frequent diagnosis of unruptured aneurysms. Because the most devastating complication of an unruptured aneurysm is subarachnoid hemorrhage, it has been considered desirable to treat these aneurysms before they rupture. However, the optimal treatment strategy for patients with unruptured aneurysms remains controversial. The management decision requires knowledge of the natural history and an accurate assessment of the risks related to various treatment options. On December 10, 1998 the New England Journal of Medicine published an article by the International Study of Unruptured Intracranial Aneurysms Investigators. The study retrospectively assessed the natural history of unruptured aneurysms in 1449 patients; in addition, treatment-related mortality and morbidity were examined in a prospective cohort of 1172 patients. The major finding was that the rate of rupture for aneurysms smaller than 10 mm in diameter in patients with no history of subarachnoid hemorrhage was 0.05% per year, and that the mortality and morbidity associated with surgery greatly exceeded the risk of rupture in such patients. This report has generated tremendous controversy in the treatment of unruptured aneurysms and has influenced our decision making. The results of this study are critically analyzed and potential flaws presented. To develop recommendations for treatment, the literature was reviewed. The conclusion of this search is that there is insufficient evidence to recommend a standard of management. Therapeutic guidelines are provided, particularly for patients with small incidental aneurysms and no history of subarachnoid hemorrhage.

Intracranial aneurysms: CT angiography and MR angiography for detection prospective blinded comparison in a large patient cohort

PURPOSE

To compare computed tomographic (CT) angiography and magnetic resonance (MR) angiography with intraarterial digital subtraction angiography (DSA) in the detection of intracranial aneurysms.

MATERIALS AND METHODS

One hundred forty-two patients underwent intraarterial DSA to detect aneurysms. CT angiography, three-dimensional time-of-flight MR angiography, and intraarterial DSA were performed contemporaneously. Film hard-copy images and maximum intensity projection reconstructions of the CT angiograms and MR angiograms were reviewed at different times.

RESULTS

The accuracy per patient for the best observer was 0.87 at CT angiography and 0.85 at MR angiography. The accuracy per aneurysm for the best observer was 0.73 at CT angiography and 0.67 at MR angiography. Differences between readers and modalities were not significant. Interobserver agreement was good: kappa value of 0.73 for CT angiography and of 0.74 for MR angiography. The sensitivity for detection of aneurysms smaller than 5 mm was 0.57 for CT angiography and 0.35 for MR angiography compared with 0.94 and 0.86, respectively, for detection of aneurysms 5 mm or larger. The accuracy of both CT angiography and MR angiography was lower for detection of internal carotid artery aneurysms compared with that at other sites. With low observer confidence, the likelihood of correct interpretation was significantly poorer.

CONCLUSION

CT angiography and MR angiography have limited sensitivity in the detection of small aneurysms but good interobserver agreement. There is no significant difference in diagnostic performance between the noninvasive modalities.

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.

Subarachnoid haemorrhage: diagnosis, causes and management

The incidence of subarachnoid haemorrhage (SAH) is stable, at around six cases per 100 000 patient years. Any apparent decrease is attributable to a higher rate of CT scanning, by which other haemorrhagic conditions are excluded. Most patients are <60 years of age. Risk factors are the same as for stroke in general; genetic factors operate in only a minority. Case fatality is approximately 50% overall (including pre-hospital deaths) and one-third of survivors remain dependent. Sudden, explosive headache is a cardinal but non-specific feature in the diagnosis of SAH: in general practice, the cause is innocuous in nine out of 10 patients in whom this is the only symptom. CT scanning is mandatory in all, to be followed by (delayed) lumbar puncture if CT is negative. The cause of SAH is a ruptured aneurysm in 85% of cases, non-aneurysmal perimesencephalic haemorrhage (with excellent prognosis) in 10%, and a variety of rare conditions in 5%. Catheter angiography for detecting aneurysms is gradually being replaced by CT angiography. A poor clinical condition on admission may be caused by a remediable complication of the initial bleed or a recurrent haemorrhage in the form of intracranial haematoma, acute hydrocephalus or global brain ischaemia. Occlusion of the aneurysm effectively prevents rebleeding, but there is a dearth of controlled trials assessing the relative benefits of early operation (within 3 days) versus late operation (day 10-12), or that of endovascular treatment versus any operation. Antifibrinolytic drugs reduce the risk of rebleeding, but do not improve overall outcome. Measures of proven value in decreasing the risk of delayed cerebral ischaemia are a liberal supply of fluids, avoidance of antihypertensive drugs and administration of nimodipine. Once ischaemia has occurred, treatment regimens such as a combination of induced hypertension and hypervolaemia, or transluminal angioplasty, are plausible, but of unproven benefit.

Unruptured Intracranial Aneurysms: Appraisal of the Literature and Suggested Recommendations for Surgery, Using Evidence-based Medicine Criteria

OBJECTIVE

The literature on unruptured intracranial aneurysms is reviewed, and an attempt is made to stratify it according to the weight of the evidence. Recommendations for surgery are suggested, using evidence-based criteria.

METHODS

A MEDLINE search was performed for 1966 to 1999. The focus was restricted to surgical management rather than other types of management, such as endovascular treatments. Each article was classified as Class I, II, or III according to the weight of the evidence. Some articles, such as literature reviews and data analyses, did not fit this classification and were grouped separately. Recommendations are based on the evidence available.

RESULTS

Forty-five articles were reviewed. Thirteen articles contained information on the natural history, 19 contained data on the risks of surgery, and 2 contained information on both. In addition, 11 contained analyses of costs and benefits. None met the criteria for Class I evidence. Seven articles on the natural history and 7 on the risks of surgery met the criteria for Class II evidence, and 6 and 12, respectively, met those for Class III evidence. The remainder of the articles were analyses or review articles.

CONCLUSION

There is insufficient evidence to recommend a standard of management. As a therapeutic guideline, conservative treatment is recommended for small aneurysms (&lt;10 mm) and asymptomatic nongiant aneurysms in older people, whereas surgery is recommended for larger aneurysms in younger people and symptomatic aneurysms in fit patients. Other recommendations can be justified only as therapeutic options, using evidence-based criteria. Areas for future investigation are discussed.

Can noninvasive imaging accurately depict intracranial aneurysms? A systematic review

PURPOSE

To perform a systematic review to determine the accuracy of computed tomographic (CT) angiography, magnetic resonance (MR) angiography, and transcranial Doppler ultrasonography (US) in depicting intracranial aneurysms.

MATERIALS AND METHODS

A 1988-1998 literature search for studies with 10 or more subjects in which noninvasive imaging was compared with angiography was undertaken. Studies meeting initial criteria were evaluated by using intrinsically weighted standardized assessment to determine suitability for inclusion. Studies scoring greater than 50% were included.

RESULTS

Of 103 studies that met initial criteria, 38 scored greater than 50%. CT angiography and MR angiography had accuracies per aneurysm of 89% (95% CI: 87%, 91%) and 90% (95% CI: 87%, 92%), respectively. For US, data were scanty and accuracy was lower, although the CIs overlapped those of CT angiography and MR angiography. Sensitivity was greater for detection of aneurysms larger than 3 mm than for detection of aneurysms 3 mm or smaller-for CT angiography, 96% (95% CI: 94%, 98%) versus 61% (95% CI: 51%, 70%), and for MR angiography, 94% (95% CI: 90%, 97%) versus 38% (95% CI: 25%, 53%). Diagnostic accuracy was similar for anterior and posterior circulation aneurysms.

CONCLUSION

CT angiography and MR angiography depicted aneurysms with an accuracy of about 90%. Most studies were performed in populations with high aneurysm prevalence, which may have introduced bias toward noninvasive examinations.

Clinical features of intracranial aneurysms in siblings

OBJECTIVE

Among the family members of patients with aneurysmal subarachnoid hemorrhage (SAH), siblings have been documented to be at high risk of SAH and to have a high prevalence of unruptured aneurysms. We studied the distinctive features of aneurysms in siblings and attempted to determine the risk of rupture.

METHODS

We analyzed detailed data on 159 patients with siblings who had ruptured and unruptured aneurysms in 77 families from throughout Japan.

RESULTS

Seventy-three percent of the patients were female, and the mean age at the time of rupture was 55.6 years. In 39 families, two or more siblings had SAH. Eighty of 107 patients with ruptured aneurysms and 28 of 52 with unruptured aneurysms had a family history of SAH in siblings (P = 0.0082). Multiple and mirror-image aneurysms were found in 42 and 21 patients, respectively. Among 218 aneurysms, middle cerebral artery aneurysms were the most common type (43%). Anterior communicating artery aneurysms were underrepresented (15%). There were significantly more ruptured than unruptured anterior communicating artery aneurysms, compared with other aneurysms (P = 0.01).

CONCLUSION

The clinical features of aneurysms in siblings in this population agreed well with those reported for familial intracranial aneurysms and SAH, except for the age at the time of rupture. It is suggested that the risk of rupture is greater when patients with unruptured aneurysms have siblings with aneurysmal SAH and/or anterior communicating artery aneurysms.