Asymptomatic Cerebral Aneurysms Research Articles

Abstract WMP32: Endovascular Coiling Recommended for Management of Elderly Patients With Unruptured Cerebral Aneurysm Based on the Nationwide Database in Japan

Introduction: Asymptomatic unruptured cerebral aneurysms (UCAs) are frequently discovered at brain check-up in Japan. The Japanese population has a high proportion of elderly individuals, and Japan has the highest life expectancy at birth worldwide. This aging of the population is expected to occur in other countries in the near future. Age is a significant risk factor for UCA rupture in elderly patients. This study aims to clarify the risk factors of age by comparing the outcome at discharge for UCAs between non-elderly (<65 years) and elderly (≥65 years) patients, based on the Diagnosis Procedure Combination database, the national database of in-hospital patients in Japan. Hypothesis: Effective treatment for UCA in elderly patients will be required in the future. Endovascular coiling might be a better choice for UCA in the elderly. Subjects and Methods: Outcome at discharge was investigated in two patient groups registered in the nationwide database from 2010 through 2015 in Japan. The risk factors were identified by multivariate logistic regression analysis for poor outcome using the Barthel index <90 at discharge in each group. Age, sex, location of UCA, clipping or coiling, medical history, hospital volume, and academic were evaluated as variables. Additionally, propensity score-matched analysis was conducted in both groups to compare the outcomes between clipping and coiling. Results: The risk factors for poor outcome at discharge were basilar artery aneurysm (odds ratio [OR], 1.7-2.6; 95% confidence interval [CI], 1.1-4.6), low volume hospital (OR, 2.0-2.5; 95% CI, 1.6-3.7), and diabetes mellitus (OR, 2.0-2.5; 95% CI, 1.6-3.7) in both groups, and age (OR, 1.1; 95% CI, 1.1-1.1) and clipping (OR, 1.7; 95% CI, 1.3-2.1) only in the elderly group. Hyperlipidemia was an adverse risk factor in both groups (OR, 0.6-0.7; 95% CI, 0.4-0.9). No significant difference between clipping and coiling was found in the non-elderly group (p=0.91), but better outcome by coiling was found in the elderly group (p<0.001) by propensity score-matched analysis. Conclusions: Treatment of UCA should be performed in high volume hospitals after control of diabetes mellitus. Endovascular coiling is recommended for UCA in elderly patients.

Impact of Reducing the Procedure Time on Thromboembolism After Coil Embolization of Cerebral Aneurysms.

Background: There is still controversy regarding which procedure-related factors affect the occurrence of periprocedural thromboembolism. This study aimed to investigate which procedure-related risk factors can be modified to prevent adverse thromboembolic events after coil embolization of intracranial aneurysm.Methods: Using a single-center database, we retrospectively identified a consecutive series of patients with symptomatic and asymptomatic cerebral aneurysms treated with coil embolization. We evaluated the following procedure-related factors: procedure time, procedure methods (simple coiling, stent-assisted coiling, and use of multiple microcatheters), and number of coils inserted. The primary outcome was the development of thromboembolism before and after coil embolization confirmed by diffusion-weighted imaging (DWI) irrespective of the location of the procedure. Pearson's chi-square, Student's t-test, multivariable logistic regression analysis, and sensitivity analysis with multinomial logistic regression analysis were used in the statistical analyses.Results: Of 180 cases enrolled, 146 (81.1%) had evidences of thromboembolism confirmed by DWI, and 13 (7.2%) had neurologic symptoms. Among the documented modifiable procedure-related factors, every 10 min increase in the procedure time was independently associated with the risk of thromboembolism, after adjusting the analysis (adjusted odds ratio 1.11; 95% confidence interval 1.01–1.21). The coiling methods, use of multiple catheters, and number of coils inserted did not change the effect of the procedure time on thromboembolic events (p for interactions > 0.05).Conclusion: This study showed that the procedure time might be the most effective modifiable factor for reducing thromboembolic events irrespective of the procedure methods used during coil embolization of cerebral aneurysms.

Endovascular coiling for cerebral aneurysm: single-center experience in Egypt

BackgroundEndovascular management for cerebral saccular aneurysm has evolved in the last decade with evolution in both equipment and material. Coiling is still the mainstay of cerebral aneurysm endovascular management. In Egypt, practice outcome needs evaluation especially at low-volume centers.PurposeTo discuss the technical and management outcomes of our first symptomatic and asymptomatic cerebral saccular aneurysm case series treated with simple coiling.Patients and methodsClinical, treatment, and outcome variables of consecutive symptomatic and asymptomatic cerebral aneurysm cases treated with simple coiling between January 2011 and June 2016 in one center were analyzed.ResultsIn 31 patients, 35 aneurysms were found, 34 aneurysms (97.1%) were treated by endovascular coiling, and only one aneurysm (2.9%) was not fit for endovascular treatment. Total occlusion was achieved in 29 aneurysms (82.9%). Neck remnants were present in 4 aneurysms (11.4%). Partial coiling (incomplete occlusion) was achieved in 1 aneurysm (2.9%). Regarding functional outcome (mRS at discharge), 25 patients had good outcome (mRS = 0, 1, 2, 3) and 6 patients had poor outcome (mRS = 4, 5, 6).ConclusionThe endovascular coiling could be used as a first-choice option for treatment of saccular cerebral aneurysms at our center despite the low case rate.

Abstract TP86: Post Hoc Subgroup Analysis of Unruptured Cerebral Aneurysm in Japan Special Reference to Small Sized Aneurysm

Introduction: In Japan, asymptomatic unruptured cerebral aneurysms (UCA) are frequently discovered at brain check-ups. The overall annual rupture rate of these aneurysms has been reported as 0.95% according to UCAS Japan. Japanese people have a 2.8-times increased risk of rupture in UCA according to PHASES score. According to the recent reports, the rate of the small sized ruptured cerebral aneurysm ≤ 5mm (RCA) was over 35%. In this paper, we discuss the post hoc subgroup analysis of UCA in Japan special reference to small aneurysms. Subjects and Methods: From January 2001 to March 2004, a total of 6697 UCAs among 5720 patients were prospectively registered from any one of 283 institutions in Japan. In a subgroup of small UCAs ≤ 4mm (sUCA), aneurysms which developed a subarachnoid hemorrhage were extracted for this post hoc analysis. Intrapatient comparisons of each sUCAs were carried out using aneurysm specific factors such as size, location, calcification, thrombosis and shape, and patient specific factors such as age, sex, the reason of discovery for UCA, hypertension, hyperlipidemia, smoking, polycystic kidney and old cerebral infarction. Multivariate logistic regression analysis for rupture by JMP software was performed. Results: Eight sUCAs among 3132 sUCAs were ruptured and the annual rupture rate was 0.35% / year. By multivariate logistic regression analysis for rupture, the sCUA discovered by brain check-ups (OR: 3.69, CI: 1.02 – 15.5) and non-hyperlipidemia (OR: 5.65, CI: 1.11 – 103.9) were significant risk factors. The annual rupture rate of sUCA discovered by brain check-ups and with non-hyperlipidemia were 0.62 % and 0.42 %, respectively. Conclusions: SUCA has not indicated the category for radical treatment of UCA, however, the countermeasure for sUCA should be required to reduce the incidence of subarachnoid hemorrhage. Using of statin and any psychogenic stress might be related to rupture of sUCAs. Further precise research should be needed about the treatment for sUCA.

Tactics of surgical treatment of patients with unruptured asymptomatic cerebral aneurysms

To clarify the indications for surgical treatment and the principles for choosing a surgical technique for patients with unruptured asymptomatic aneurysms (UAAs) based on the results of direct and endovasal operations performed at the Burdenko Neurosurgical Institute and on the literature data. The study included 694 UAA patients (481 females (69.3%) and 213 males (30.7%)) operated on at the Burdenko Neurosurgical Institute from 1997 to 2013. The patients' age ranged from 1 to 74 years (mean age, 48.3 years). Multiple aneurysms were in 126 (18.2%) patients. Anterior circle of Willis aneurysms were in 92.8% of cases. Among these, internal carotid artery (ICA) aneurysms (46.3%) and middle cerebral artery (MCA) aneurysms (30.8%) were predominant. Microsurgical and endovascular interventions on aneurysms were performed in 665 patients (95.8%). Complete aneurysm exclusion was achieved in 94.8% of cases. A pronounced neurological deficit developed in 8 (1.2%) patients, and a moderate neurological deficit developed in 62 (9.3%) patients. Postoperative mortality was 0.5%. Surgical treatment of UAAs is associated with low disability and mortality rates. All UAAs need to be operated on, especially in young and middle age patients, if surgery is technically possible, and there are no concomitant diseases contraindicating the intervention. The choice of an UAA exclusion technique is made based on the general principles of surgical treatment of cerebral aneurysms. At present, the method of choice is endovascular surgery for most cases of vertebrobasilar basin and ICA aneurysms and a microsurgical intervention for anterior cerebral artery and MCA aneurysms.

Middle Cerebral Artery Bifurcation Aneurysms: When and How to Treat Asymptomatic Unruptured Aneurysms

Management of unruptured asymptomatic cerebral aneurysms is one of the most highly controversial and most discussed topics in vascular neurosurgery. The increasing availability and use of imaging modalities, including computed tomography with and without angiography, magnetic resonance imaging, magnetic resonance angiography, and digital subtraction angiography, has resulted in an increased number of diagnosed unruptured aneurysms. This trend has led more patients to ask if their vascular lesion should be treated and if so when should such treatment be done. The current medical literature shows conflicting data regarding the natural history of unruptured cerebral aneurysms and the risks associated with their management. In 2003, the International Study of Unruptured Intracranial Aneurysms (ISUIA) (11) showed that aneurysms in the anterior circulation measuring <7 mm had a 5-year cumulative risk of rupture of 0% in patients with no history of subarachnoid hemorrhage and that aneurysms measuring 7e12 mm had a 5-year cumulative risk of 2.6%, making the risk associated with any treatment modality

Prevalence of Asymptomatic Cerebral Aneurysm in General population and Ischemic Stroke Patient (I2-4A)

Prevalence of Asymptomatic Cerebral Aneurysm in General population and Ischemic Stroke Patient (I2-4A)

Prevalence of Asymptomatic Cerebral Aneurysm in General population and Ischemic Stroke Patient (S47.007)

Prevalence of Asymptomatic Cerebral Aneurysm in General population and Ischemic Stroke Patient (S47.007)

Delayed rupture of a basilar artery aneurysm treated with coils: Case report and review of the literature

Delayed rupture of a previously unruptured cerebral aneurysm after uneventful saccular coil packing is rare, particularly when the quality of aneurysm occlusion is appropriate (neck remnant or total occlusion). The present report describes the case of a 70-year-old woman with an incidentally detected, asymptomatic, small basilar tip non-thrombosed aneurysm who experienced rupture of the aneurysm 2 years after coiling. Cerebral angiography taken on the day of rupture revealed only small recanalization of the aneurysm neck with no dome-filling. This is the first report of delayed rupture due to minor recurrence of a previously unruptured small asymptomatic cerebral aneurysm after saccular coil packing. A literature review of 26 reports of late bleeding after coil embolization of previously unruptured cerebral aneurysms showed that dome-filling after coil embolization, symptomatic aneurysms and large/giant aneurysms all increase the risk of delayed rupture in previously unruptured aneurysms after saccular coil packing.

Precise mapping system of entrance skin dose during endovascular embolization for cerebral aneurysm

Abstract Although several cases of radiation-induced skin injury (RSI) have been reported in association with neurointerventional procedures, such as endovascular embolization for cerebral aneurysm, the absorbed doses are not directly measured in most cases. We therefore built a direct measurement system in order to simplify determination of the entrance skin dose (ESD) during neurointerventional procedures. This system was then applied to patients undergoing long and repetitive procedures in order to establish the efficacy of precise mapping of ESDs using a number of radiophotoluminescence glass dosimeters (RPLDs) and to avoid RSI. We also analyzed the correlation between maximum ESDs and angiographic parameters in order to estimate maximum ESD in real-time. ESD was measured in 35 procedures in 34 cerebral aneurysm patients with a median age of 65 years (range, 38–79 years). Patients were measured for ESDs while wearing a fitted dosimetry cap equipped with 60 RPLD chips throughout the procedure. Angiographic parameters, including total fluoroscopic time and dose-area product (DAP), were recorded. The Pearson correlation test was used to determine the relationship between maximum ESD and each parameter. Five of thirty-five procedures showed temporal epilation (14.3%). The correlations between a patient’s maximum ESD and total fluoroscopic time and DAP were r = 0.7372, P We concluded that the regional ESD with geometric information could be obtained by applying the RPLDs. Although this passive dosimetry system may not entirely prevent RSI in real-time, precise dose mapping accompanied by monitoring of angiographic parameters during the procedure should contribute to reducing X-ray dose accumulation in repeated prophylactic endovascular embolization for asymptomatic cerebral aneurysm.

小型の無症候性未破裂脳動脈瘤に対する治療適応と外科治療の現状・展望(&lt;特集&gt;未破裂脳動脈瘤治療の展望)

未破裂脳動脈瘤は,破裂例と異なり治療の時期,方法,施設と術者の選択の幅が大きく,また切迫破裂ないしmass effectを呈する多くは,大型の症候性未破裂動脈瘤と,脳ドックなどで偶然発見された小型の無症候性未破裂動脈瘤との間で対応に差が生じるのは明らかで,後者に「許容されうる」合併症の余地は皆無に近い.一定の手術経験者が小型の未破裂動脈瘤手術を行った際に問題となる合併症は主に穿通枝閉塞,脳神経障害であり,ガイドラインに基づいた症例選択,術者や施設の経験の蓄積とおよび内視鏡,術中蛍光血管撮影,モニタリングの進歩などによる確認水準の向上により,これら合併症の多くは克服可能となった.自経例や最近の報告では,手術morbidityは数%,死亡率はほぼゼロである.この治療水準は,完全な動脈瘤頚部閉塞よりも合併症回避を優先させる判断に基づいたものであり,その理念は小型の無症候性未破裂脳動脈瘤においてはコンセンサスを得ているものと考えられる.

Theoretical model for quantifying the operative benefit of unruptured cerebral aneurysms by location, age and size

Aim: The indications for surgery on unruptured asymptomatic cerebral aneurysms are still unclear. Previous mathematical models that have addressed this issue group all aneurysm sizes and locations into one category and report one average rupture and surgical complication rate. In this report the authors used a comprehensive review of the literature and mathematical models to create an online open-access program to quantify the benefit of surgery on unruptured aneurysms according to age, size and location. Materials and methods: Using 5-year prospective International Study of Unruptured Intracranial Aneurysms data and a literature search of 30 additional studies (10,545 patients), we calculated annual rupture rates and operative complication rates for aneurysms by size (5–25 mm), patient age (40–70 years) and 14 common locations. Using this location-, size- and age-specific data, a mathematical model was created by solving differential equations measuring the survival rate of a patient with and without an unruptured aneurysm. Operative benefit was calculated by comparing the quality-adjusted life year outcomes of surgical versus conservative management. Results: We focused on three controversial, high prevalence aneurysm locations (supraclinoid, cavernous and basilar bifurcation). Despite vastly different operative mortality rates and annual rupture rates, 5 mm supraclinoid internal carotid artery aneurysms and basilar bifurcation aneurysms revealed similar operative indications. Small basilar and supraclinoid aneurysms (∼5 mm) only yielded operative benefits in young patients (∼40 years of age). By contrast, larger aneurysms (10 and 15 mm) yielded an operative benefit for a wider range of ages. There was no age and size combination that yielded an operative benefit for cavernous aneurysms. Conclusion: In any mathematical model, some simplifications are inevitable. However, we believe this model is successful in providing helpful estimates and guidelines when delegating patients to surgical or medical management.

Development of cranial nerve palsy shortly after endosaccular embolization for asymptomatic cerebral aneurysm: report of two cases and literature review

We report two cases of asymptomatic cerebral aneurysm in which cranial nerve palsy (CNP) developed shortly after symbolization. The CNP occurred immediately in case 1, but case 2 showed the CNP 30 h after symbolization. Although both aneurysms had increased in size on follow-up angiography, case 2 who showed dome re canalization resulted in progressive CNP deterioration. These findings suggest that the CNP may result not only from mechanical compression by coils but also from inflammation induced by perpendicular thrombosis, and that the prognosis of the CNP may be influenced by dome re canalization. This complication should be kept in mind in treatment for asymptomatic aneurysms adjacent to the cranial nerves.

未破裂・無症候性脳動脈瘤の手術成績―高次脳機能，ＭＲＩ，脳血流評価の意義―

We evaluated neuropsychological function, magnetic resonance (MR) images and cerebral blood flow (CBF) in patients with unruptured asymptomatic cerebral aneurysms. Among consecutive operations (n=73) on 70 patients since 2000, direct surgery was performed in 53 operations on 50 patients, and intravascular surgery was performed in 20 operations on 20 patients. Surgical results of direct surgery were studied. Direct surgery was selected mainly for patients with small and anterior circulation aneurysms. MR imaging was conducted 1 week after surgery, and Wechsler Adult Intelligence Scale-Revised (WAIS-R) examination and CBF measurement using 133Xe-SPECT were done before and 1 month after surgery. Abnormal neurological findings were recognized postoperatively in 26% of surgeries. Among them, visual disturbance was permanent in 4% of surgeries, all of which were surgeries for paraclinoid internal carotid artery aneurysms. WAIS-R results deteriorated in 26% of surgeries at 1 month and at least in 5% of surgeries at 1 year after surgery. MR images at 1 week after surgery revealed brain damage in 30% of surgeries and subdural fluid collection in 19% of surgeries. Patients with large brain damage or thick subdural fluid collection frequently showed neurological deficits and/or WAIS-R deterioration. These complications were recognized frequently in patients with ACoA aneurysms. Resting CBF decreased significantly in the area supplied by the anterior cerebral artery and anterior border zone on the operated side postoperatively. The brain damage and subdural fluid collection were observed frequently and caused neurological deficits and neuropsychological dysfunction, although these were usually transient. It may be necessary to evaluate neuropsychological function, MRI and CBF in patients with unruptured asymptomatic cerebral aneurysms to improve surgical results.

未破裂・無症候性脳動脈りゅうの治療―手術成績と今後の課題について―

We evaluated neuropsychological function and MR images in patients with asymptomatic cerebral aneurysms in order to improve the results of surgical treatment. Consecutive operations (n=53) on 51 patients since 2000 were included in this study. Direct surgery (DS) was performed in 37 operations on 35 patients, and intravascular surgery (IVS) was performed in 16 operations on 16 patients. IVS was selected for patients with large-sized or posterior circulation aneurysms. MR imaging was conducted 1 week after surgery and WAIS-R examination was done 1 month and 1 year after surgery. In the DS group, abnormal neurological findings were recognized postoperatively in 27% of surgeries. Among them, visual disturbance was permanent in 5% of surgeries, all of which were surgeries for paraclinoid internal carotid artery aneurysms. WAIS-R results deteriorated in 26% of surgeries at 1 month and in 4% of surgeries at 1 year after surgery. MR images at 1 week after surgery revealed brain damage in 38% of surgeries and subdural fluid collection in 18% of surgeries. Of patients with anterior communicating artery aneurysms, 33% showed abnormal neurological findings, 33% showed deterioration of WAIS-R results, although almost all these findings were transient, and 58% showed brain damage upon evaluation of MR images at 1 week after surgery. In the IVS group, abnormal neurological findings were recognized postoperatively in 19% of patients, and hemiparesis was permanent in 6% of patients. Cerebral infarction was observed in 31% of patients on MR images at 1 week after surgery. Of patients with partially thrombosed aneurysms, 75% showed cerebral infarction and 50% showed abnormal neurological findings transiently. To improve surgical results, selection of treatment or surgical approaches should be strictly based on evaluation of postoperative MR images and neuropsychological function, as well as on neurological findings and outcome. Results of DS were not satisfactory in patients with anterior communicating artery or paraclinoid internal carotid artery aneurysms, and results of IVS were discontented in patients with partially thrombosed aneurysms.

Endovascular Treatment of Asymptomatic Cerebral Aneurysms: Anatomic and Technical Factors Related to Ischemic Events and Coil Stabilization

The present study assessed the safety and efficacy of embolization using Guglielmi detachable coils (GDCs) in 100 asymptomatic cerebral aneurysms classified as sidewall (70) or terminal (30) aneurysms according to the parent artery (68 small aneurysms with a small neck, 21 small aneurysms with a wide neck, and 11 large aneurysms). A balloon-assisted technique was used in 49 aneurysms. Immediate angiography revealed that 71 aneurysms were completely obliterated. Transient deficits occurred in 19 patients, permanent deficits in four patients, and one patient died. Most complications occurred during or immediately after treatment and resolved within a few minutes to a few weeks. None of the surviving patients manifested significant morbidity at 1-year follow up. Follow-up angiographic study was performed in 79 aneurysms. Rates of recanalization and progressive thrombosis (total occlusion of the residual aneurysm at follow up) were 11% and 38%, respectively, in sidewall aneurysms, and 26% and 0%, respectively, in terminal aneurysms. Treatment with GDCs was effective for patients with small aneurysms with small necks, the morbidity was acceptable, and progressive thrombosis occurred during the follow-up period. GDC treatment achieved unsatisfactory results in patients with small terminal aneurysms with wide necks and in large aneurysms, because the obliteration rate was low, and the recanalization and complication rates were high. Multivariate analysis showed that complete occlusion was associated with small-necked aneurysms, and ischemic events tended to occur in terminal aneurysms and in aneurysms treated by the balloon-assisted technique.

テント上無症候性未破裂脳動脈瘤の治療方針

テント上の無症候性未破裂脳動脈瘤の自然歴と手術成績を文献学的に検討し,下記の結果を得た.1)年間出血率は1〜2%であり,国際共同研究で示された出血率は対象とした症例の選択にバイアスがかっかている可能性が高く,考慮しなくてよいと考えられる.2)5mm以下の小さな脳動脈瘤および70歳以上の高齢者の脳動脈瘤も出血する可能性がある.3)手術成績は死亡率1%以下,悪化率4%であった.4)手術法は現在のところ直達手術が第一に考慮されるべき方法である.以上の結果から,巨大脳動脈瘤を除くとテント上の無症候性未破裂脳動脈瘤は,正常な日常生活が可能で,重篤な全身合併のない例では5mm以下の脳動脈瘤を含め70歳以上でも手術適応があり,巨大脳動脈瘤では手術がむずかしく手術成績もやや悪いことから,70歳以下の例で手術適応があると考える.

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

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

未破裂脳動脈りゅうの治療指針

An increasing number of cases of incidental cerebral aneurysms are currently being reported. However, the indications for surgery of unruptured asymptomatic cerebral aneurysms are still unclear. The benefit of treatment ultimately depends on the relative risk of subsequent aneurysm rupture in untreated patients versus the risk involved in surgery. We report a series of 90 cases of unruptured aneurysms, admitted and treated over a period of 6 years and 1 month (1993. 12. 1-1999. 12. 31). General information about the natural history of incidentally discovered aneurysms was given to the patients and their relatives. Informed consent was based on the fact that subarachnoid hemorrhage was associated with a poor prognosis, while excellent operative results were common in patients with unruptured aneurysms. Sixty-six patients underwent surgery, and the remaining 24 patients who did not receive surgery were followed up at periods ranging from 1.5 months to 5 years and 9 months. Of the 66 patients who were operated on, there were 11 (17%) cases of postoperative complications, including 5 venous infarctions, 2 memory disturbance, 1 recurrent cerebral infarction, 1 visual disturbance, 1 cerebral embolism and 1 intraoperative rupture. Three patients (4.5%) did not recover. The remaining 8 patients, however, recovered with time or through treatment. Among the 24 patients who were treated conservatively, only 2 developed rupture of the aneurysms (0.4% annual rupture rate) and both made an uneventful recovery. It is our clinical impression, however, that they harbor an unruptured aneurysm with at least mild trepidation. Aneurysm size, location, and number were risk predictors for surgical morbidity in patients with unruptured aneurysms. This experience suggests that if intact aneurysms are treated surgically, careful preoperative evaluation and precise microsurgical techniques are essential. An endovascular approach or some skull base surgical techniques should be considered to obtain better results.

Incidental asymptomatic cerebral aneurysms in patients with extracranial cerebrovascular disease: is this a case against carotid endarterectomy without arteriography?

As less arteriography is performed before carotid surgery, concern arises about missing occult cerebral aneurysms and possible adverse outcomes. A study was conducted by the divisions of vascular surgery and neurosurgery of Northwestern University Medical School to evaluate the frequency of incidental cerebral aneurysms and outcomes of patients with extracranial cerebrovascular disease and asymptomatic cerebral aneurysms. From October 1995, through March 1997, 200 patients underwent intracranial and extracranial cerebrovascular angiography for evaluation of extracranial disease. Demographic data, symptoms, data of vascular lesions, surgical treatment and outcomes of stroke and death were recorded prospectively. Two patients (1%) had asymptomatic cerebral aneurysms found on angiography. Six more patients were referred with a known asymptomatic cerebral aneurysm with extracranial disease during this same period. Of these eight patients, five underwent extracranial vascular reconstruction surgery and seven received treatment for their aneurysms. There were two stroke complications, both occurred after treatment of a basilar artery aneurysm. One of these patients died. No aneurysms ruptured following 203 extracranial revascularizations during this same period. On the basis of the low prevalence of diagnosing coincidental cerebral aneurysms during work-up of extracranial disease, as well as the lack of evidence that carotid surgery predisposes to aneurysm rupture in these patients in both our study and the literature review, it is concluded that coexisting extracranial disease and asymptomatic cerebral aneurysms do not pose a case against carotid surgery without routine arteriography. However, arteriography should be considered in selected groups of patients where the yield of intracranial aneurysms is high; these include patients with a familial history of cerebral aneurysms, autosomal dominant polycystic kidney disease, extracranial internal carotid artery medial fibrodysplasia, Takayasu's arteritis, alpha1-antitripsin deficiency and atypical clinical presentations, including headache.