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

Prevalence of cerebral aneurysms in autopsy studies: a review of the literature

Cerebral aneurysms (CAs) are one of the most important causes of stroke, but details of their prevalence remain under-researched. Autopsy data for CAs were reviewed using standard search engines. Based on previously published autopsy and clinical studies, the prevalence of CAs with respect to age, gender, and aneurysm site, size, and multiplicity was investigated, and the natural course of CA prevalence was estimated. In autopsy studies, the prevalence of CAs across all age groups was 0.3-4.0% for unruptured cerebral aneurysms (UCAs) and 1.3-7.6% for CAs including UCAs and ruptured cerebral aneurysms (RCAs). Patients with UCAs were generally older than those with RCAs. Middle cerebral artery aneurysms were more predominant in autopsy studies than in clinical studies. UCAs tended to be smaller than RCAs, and minute UCAs (< 2 mm), diagnosed microscopically at autopsy and thought to be in the very early stages of formation, were present in 10-20% of the general population. Taking into consideration the clinical data for UCAs and RCAs, 10% of minute UCAs enlarge to major UCAs (≥ 2 mm) detectable by conventional imaging techniques, and 10% of major UCAs eventually rupture within 10 years. The high prevalence of UCAs and RCAs in the elderly and women can be attributed to the more frequent occurrence of minute UCAs in these populations. Minute UCAs occur at a high rate, but only a few enlarge to become major UCAs and rupture. Further advances in diagnostic technology are essential for revealing the true natural course of CA prevalence.

Contralateral Clipping of Multiple Intracranial Aneurysms

The reported incidence of multiple intracranial aneurysms (MIA) is approximately 7-35% of all intracranial aneurysms. The primary goal in the management of MIAs is to secure the ruptured aneurysm and to treat as many of the remaining lesions as possible without affecting the outcome of the patient. In recent era endovascular treatment is the preferred treatment of multiple bilateral intracranial aneurysms if all aneurysms are amenable to addressed in single stage. But most often all aneurysms were not possible to addressed due to complexity of different aneurysms, technical limitation and infrastructure. In such scenarios options left were two stage sequential craniotomy on either sides and clipping of bilateral aneurysms or unilateral craniotomy and clipping of bilateral MIA. Bilateral two stage surgery or two stage endovascular treatment caries risk of bleeding from one of the untreated aneurysms, morbidity due to two stage and increase the cost of treatment. In properly selected cases of unilateral craniotomy and clipping of bilateral MIA secure the all aneurysm in one stage and decreased morbidity and cost of treatment. When patient selection done meticulously, clipping of MIA including contralateral side aneurysms is feasible and safe.

Microsurgical Clipping of Carotid-Ophthalmic Tandem Aneurysms: Case Report and Surgical Nuances

Tandem intracranial aneurysms (TandIAs) are rare but inherently complex, and special technical considerations are required for their surgical management. The present case highlights the key surgical aspects of two carotid-ophthalmic TandIAs incidentally found in a 60-year-old female. Both the aneurysms were superiorly projecting, regular in size, and involved the left ophthalmic segment of the internal carotid artery (ICA). The minimum distance between the necks was 3 mm. The patient underwent microsurgery because of the reported major complications rate of the endovascular treatment in the case of a very short minimum distance between the TandIAs. After cervical ICA exposure, both the aneurysms were excluded through a pterional approach. Intradural anterior clinoidectomy and unroofing of the optic canal allowed the mobilization of the left optic nerve. The more distal aneurysm was clipped before the opening of the distal dural ring of the ICA. The proximal aneurysm was clipped with two straight clips stacked perpendicular to the ICA. A small remnant was intentionally left to avoid the stenosis of the ophthalmic artery. Postoperative angiography showed the exclusion of both the aneurysms with a small dog-ear of the more proximal one. The patient was discharged neurologically intact and, after one year, the remnant remained stable. Microsurgical clipping is a definitive and durable treatment for carotid-ophthalmic TandIAs. In the case of a very short minimum distance between the aneurysms, the distal one should be clipped first to make the anterior clinoidectomy, opening of the distal dural ring of the ICA, and clipping of the more proximal aneurysm easier.

The Minimum Distance May Affect Perioperative Complications and Completed Occlusions of Endovascular Treatment for Tandem Intracranial Aneurysms: A Multi-Institutional Retrospective Study

BACKGROUND

Tandem aneurysms (TAs) are a distinct type of multiple intracranial aneurysms (IAs), the treatment strategies for which remain controversial. We aimed to reveal the clinical and angiographic outcomes of endovascular treatment as well as their risk factors in these complex multiple IAs.

METHODS

This multicenter, retrospective follow-up study was carried out in 3 hospitals in China. In total, clinical and angiographical data of 137 patients with 145 lesions (7 patients had bilateral lesions) and 315 TAs were collected. The treatment strategies were divided into full or partial treatment, single- or multiple-session treatment, and coiling (including single coiling and stent-assisted coiling)- or flow-diverting stent (FDS) treatment. Perioperative complications, as well as angiographic and clinical outcomes and their risk factors, were analyzed using univariate analysis and a multiple regression model.

RESULTS

Of treated TA lesions, 17 (16.0%) perioperative complications were found. Significant differences were found between the single- and multiple-session treatment groups (p = 0.012). At the latest follow-up, there were no significant differences in the modified Raymond Scale scores between different treatment groups. Significant differences were found in the embolization degree between the coiling and FDS groups (p = 0.038) and between the single common stent (without coiling) and the other treatment groups (p < 0.001). In IAs managed by a single LVIS stent (without coiling), 60% achieved improved or completed occlusion. Multivariate regression analysis found that a shorter minimum distance (odds ratio [OR] 5.967, 95% confidence interval [CI] 1.366-26.074; p = 0.018), multiple-session treatment (OR 9.961, 95% CI 1.707-58.127; p = 0.011), and diabetes (OR 8.106, 95% CI 1.928-34.084; p = 0.004) were predictors of perioperative complications, while shorter minimum distance (OR 5.619, 95% CI 1.493-21.152; p = 0.011), greater diameter ratio (OR 3.621, 95% CI 1.014-12.937; p = 0.048), and greater size ratio (OR 2.424, 95% CI 1.007-5.834; p = 0.048) were predictors of low completed occlusion rate.

CONCLUSIONS

Both coiling and FDS can be utilized safely and can achieve similar clinical outcomes. FDS and LVIS are recommended for IAs that do not require embolization but cannot be prevented from being covered by stents. A multiple-session treatment may increase the treatment risk, and the minimum distance may affect the incidence of perioperative complications and completed occlusions. Further hemodynamic and prospective studies on such TAs in close proximity to one another are needed.

Risk factors involved in the formation of multiple intracranial aneurysms

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Fusion of subarachnoid hemorrhage data and computed tomography angiography data is helpful to identify the rupture source in patients with multiple intracranial aneurysms

Determining the rupture source is imperative in patient with aneurysmal subarachnoid hemorrhage (SAH). About one third of SAH cases with multiple intracranial aneurysms cannot be certain of the rupture source according to the hemorrhage pattern. This study aims to identify of the rupture source in patients with multiple intracranial aneurysms by fusing SAH data and computed tomography angiography (CTA) data. This retrospective study included 52 aneurysmal SAH patients with multiple intracranial aneurysms. In the 52 patients, 36 had definitive hemorrhage patterns on computed tomography imaging. And the other 16 patients had non-definitive hemorrhage patterns, which were bewildered for us to determine the ruptured aneurysms. Fusion of SAH data and CTA data was performed to demonstrate the spatial relationship between the SAH with each aneurysm by using the 3D Slicer software. For the patients with definitive bleed patterns, all of the suspected ruptured aneurysms were confirmed to be accurate according to the surgical records. Interestingly, the suspected rupture sources were correct in 14 of 16 patients with non-definitive hemorrhage patterns. For all 52 patients with multiple intracranial aneurysms, the ruptured aneurysms were identified in 50 cases (96.2%). In conclusion, fusion of SAH data and CTA data can precisely demonstrate the spatial relationship between the SAH with each aneurysm, which is helpful to determine the ruptured aneurysm in patients with multiple intracranial aneurysms.

Surpass Flow-Diverter in the Treatment of Two Wide-Neck Aneurysms in the Scheme of an Arteriovenous Malformation Patient: A Case Study

BACKGROUND:

The cerebral arterial aneurysm, especially in the circumstances of ateriovenous malformation (AVM), has higher risk of rupture than normal isolated aneursym. Therefore, the treatment strategy needs to be plan very carefully in such case.

CASE PRESENTATION

We report a patient with 2 wide-neck aneurysms located in the feeding artery of the arteriovenous malformation and he, then, was treated by using Surpass stent (flow-diverter) to eliminate the aneurysms.

CONCLUSION:

In our case, multiple wide-neck aneurysms in combination with low risk unruptured AVM, using long Surpass stent-diversion is an effective way to eliminate all the aneurysms in the main feeding artery while still preserving the AVM anatomy.

Comparison of Flow Diversion and Coiling for the Treatment of Unruptured Intracranial Aneurysms

BACKGROUND

To systematically assess the efficacy and safety between flow diversion and coiling for patients with unruptured intracranial aneurysms.

METHODS

Potential academic articles were identified from Cochrane Library, Medline, PubMed, EMBASE, ScienceDirect, and other databases. The time range we retrieved from was the inception of electronic databases to February 2019. Gray studies were identified from the references of included literature reports. STATA version 11.0 was used to analyze the pooled data.

RESULTS

A total of 11 articles (10 retrospective studies and 1 prospective study) were involved in our study. The overall participants of the coiling group were 611, whereas 576 were in the flow diversion group. Our meta-analysis showed that flow diversion was preferable for unruptured intracranial aneurysms as its lower value of total cost per case (weighted mean difference, 5705.906; 95% confidence interval [CI], [4938.536, 6473236]; P < 0.001), fluoroscopy time per case (weighted mean difference, 25.786; 95% CI, 17.169-34.377; P < 0.001), and retreatment rates (odds ratio [OR], 7.127; 95% CI, [3.525, 14.410]; P < 0.001), at the same time, a higher rate of immediate completed occlusion (OR, 0.390; 95% CI, [0.224, 0.680]; P = 0.001) and follow-up completed occlusion (OR, 0.173; 95% CI, [0.080, 0.375]; P < 0.001) was demonstrated in the flow diversion group. There was no difference on intraoperative complication rates (P = 0.070), procedure-related mortality (P = 0.609) and rupture rates (P = 0.408), modified Rankin Scale (mRS) 0-2 at discharge (P = 0.077), and mRS 0-2 at follow-up (P = 0.484).

CONCLUSIONS

The use of flow diversion for the treatment of unruptured intracranial aneurysms may reduce total cost per case, fluoroscopy time per case, retreatment rates, and increases immediate completed occlusion and follow-up completed occlusion rates without affecting the results of mRS and intraoperative complication.

Intracranial Mirror Aneurysm: Epidemiology, Rupture Risk, New Imaging, Controversies, and Treatment Strategies

There are some controversies about the surgical treatment strategy of mirror aneurysms. Whether to choose 1-stage or 2-stage surgery, bilateral or unilateral craniotomy, or surgical or interventional treatment are the main points in dispute. In this review, the different surgery strategies faced by patients are discussed. Different surgical methods are adopted based on the patient's individual state and the location and size of the aneurysm. A new imaging method is introduced using 3D Slicer, which clearly recognizes the relationship among aneurysm, brain tissue, skull, and nerve. The 3D Slicer can help surgeons undertake adequate preoperative preparation. In addition, we also introduce some ruptured factors (e.g., age, gender, hypertension, morphologic, and hemodynamic) concerning mirror aneurysm. Systematic discussion of the controversies and methods in surgical treatment of mirror aneurysms may provide new perspectives in future research for the prevention and treatment of mirror aneurysms.

Aneurysms Arising From the Fenestrated Middle Cerebral Artery

Intracranial artery fenestration is segmental duplication of the lumen into 2 distinct channels and is known to have a low angiographical incidence of 0.3 to 0.9%. Intracranial artery fenestration is frequently associated with aneurysms, and aneurysms arising at the site of fenestrated middle cerebral artery (MCA) is extremely rare. To our best knowledge, there are only 10 such patients have been reported. Herein, the authors describe the 11th case of aneurysm arising from the fenestrated MCA. As the characteristics of fenestrated MCA aneurysms has not been well determined until now, these interesting patients are investigated and summarized.

Initially Missed or Delayed Diagnosis of Subarachnoid Hemorrhage: A Nationwide Survey of Contributing Factors and Outcomes in Japan

BACKGROUND

Subarachnoid hemorrhage (SAH) remains a significant cause of mortality in Japan. The Japan Stroke Society set out to conduct a nationwide survey to identify contributing factors and outcomes of SAH misdiagnosis.

METHODS

We initially surveyed 737 training institutes and 1259 departments in Japan between April 2012 and March 2014 for the presence of misdiagnosed SAH. Clinical information was then sought from respondents with a positive misdiagnosis. Information on 579 misdiagnosed cases was collected.

RESULTS

Most initial misdiagnoses occurred in nonteaching hospitals (72%). Of those presenting with headache, 55% did not undergo a computed tomography (CT) scan. In addition, SAH was missed in the patients who underwent CT scans. The clinically diagnosed rerupture rate was 27%. Mortality among all cases was 11%. Institutes achieving a final diagnosis were staffed by neurologists or neurosurgeons. Multivariate logistic regression analysis indicated that age (≥65), consciousness level (Japan Coma Scale score at correct diagnosis), rerupture of an aneurysm, and no treatment by clipping or coiling were significantly associated with poor clinical outcome.

CONCLUSIONS

The prognosis of misdiagnosis of SAH is severe. Neuroradiological assessment and correct diagnosis can prevent SAH misdiagnosis. When there is a possible diagnosis of SAH, consultation with a specialist is important.

Risk factors analysis of mirror aneurysms: A multi-center retrospective study based on clinical and demographic profile of patients

As a special subgroup of multiple intracranial aneurysms, mirror aneurysms are located bilaterally on the corresponding intracranial arteries. The current study sought to compare the clinical and demographic features of patients harboring mirror aneurysm, and to elucidate the corresponding risk factors. We performed a retrospective cohort study of 2641 intracranial aneurysms patients, who were admitted to our hospitals between January 2005 and June 2014. Patients were subdivided into three groups based on the inclusion criteria: (i) single (n=2250); (ii) non-mirror multiple (n=285); and (iii) mirror aneurysms (n=106). Clinical and demographic files of the three groups were collected and compared, and medical histories including stroke, hyperlipemia, hypertension, hyperglycemia, valvular heart disease were considered as potential risk factors. Potential morphological reasons for mirror cerebral aneurysms rupture, including aneurysms size, irregular walls and cerebral hemispheric dominance, were also compared. Our data showed that the male to female ratio of mirror aneurysms patients was 1:3.61, which was significantly different from that of single aneurysm (1:1.27) and multiple aneurysms (1:2.00). The prevalence of mirror aneurysms in women is higher than that in men (P<0.001). Older patients (especially 60-69 years old) also appear to be more vulnerable to mirror aneurysm than single aneurysm (P<0.001). In 84 mirror aneurysm patients the aneurysms were located on the internal carotid arteries (79.2%), most typically at the PComA or in the Cavernous ICA. Patients with medical history of hyperlipemia appear to have an increased risk of harboring mirror aneurysms. Larger aneurysm size and presence of an irregular aneurysm wall appear to be the morphological factors that predispose for mirror aneurysms rupture.

Treatment of Tandem Internal Carotid Artery Aneurysms Using a Single Pipeline Embolization Device: Evaluation of Safety and Efficacy

BACKGROUND AND PURPOSE

Tandem aneurysms are defined as multiple aneurysms located in close proximity on the same parent vessel. Endovascular treatment of these aneurysms has rarely been reported. Our aim was to evaluate the safety and efficacy of a single Pipeline Embolization Device for the treatment of tandem aneurysms of the internal carotid artery.

MATERIALS AND METHODS

A retrospective analysis of consecutive aneurysms treated with the Pipeline Embolization Device between 2009 and 2016 at 3 institutions in the United States was performed. Cases included aneurysms of the ICA treated with a single Pipeline Embolization Device, and they were divided into tandem versus solitary. Angiographic and clinical outcomes were compared.

RESULTS

The solitary group (median age, 58 years) underwent 184 Pipeline Embolization Device procedures for 184 aneurysms. The tandem group (median age, 50.5 years) underwent 34 procedures for 78 aneurysms. Aneurysms were primarily located along the paraophthalmic segment of the ICA in both the single and tandem groups (72.3% versus 78.2%, respectively, P = .53). The median maximal diameters in the solitary and tandem groups were 6.2 and 6.7 mm, respectively. Complete occlusion on the last angiographic follow-up was achieved in 75.1% of aneurysms in the single compared with 88.6%% in the tandem group (P = .06). Symptomatic thromboembolic complications were encountered in 2.7% and 8.8% of procedures in the single and tandem groups, respectively (P = .08).

CONCLUSIONS

Tandem aneurysms of the ICA can be treated with a single Pipeline Embolization Device with high rates of complete occlusion. While there appeared to be a trend toward higher thromboembolic complication rates, this did not reach statistical significance.

The Incidence and Characteristics of Patients with Small Ruptured Aneurysms (<5 mm) in Subarachnoid Hemorrhage

OBJECTIVE

Small unruptured aneurysms (<5 mm) are known for their very low risk of rupture, and are recommended to be treated conservatively. However, we encounter many patients with small ruptured aneurysms in the clinical practice. We aimed to investigate the incidence and characteristics of patients with small ruptured aneurysms.

METHODS

We reviewed all patients admitted to our hospital with subarachnoid hemorrhage from January 2005 to December 2015. The patients were divided into two groups: those with aneurysms <5 mm (group S) and those with aneurysms ≥5 mm (group L). The patient's age and sex, size and location of aneurysms, and risk factors such as hypertension, diabetes, alcohol use, and smoking were compared between the two groups.

RESULTS

Eight-hundred eleven patients were diagnosed with ruptured aneurysms, and 337 (41.6%) were included in group S. The mean size of all aneurysms was 6.10±2.99 mm (range, 0.7-37.7); aneurysms with a diameter of 4-5 mm accounted for the largest subgroup of all aneurysms. Female sex was significantly associated with the incidence of small ruptured aneurysms (odds ratio [OR] 1.50, 95% confidence intervals [CI] 1.02-2.19, p=0.037). Despite female predominance in the incidence of small ruptured aneurysms, the proportion of small ruptured aneurysms in young (<50 years) men was high. In men, there were no significant differences regarding the location of the aneurysms between group S and group L (p=0.267), with the most frequent location being the anterior communicating artery (ACoA) in both group S (50.9%) and group L (51.4%). However, in women, there were significant differences regarding the location of the aneurysms between group S and group L (p=0.023), with the most frequent locations being the ACoA (33.0%) in group S, and the posterior communicating artery (30.6%) in group L. In women, two locations were significantly associated with small (<5 mm) ruptured aneurysms: the ACoA (OR 2.14, 95% CI 1.01-4.54, p=0.047) and anterior cerebral artery (OR 3.54, 95% CI 1.19-10.54, p=0.023). Multiplicity and smoking were significantly associated with large (≥5 mm) ruptured aneurysms in women. The use of alcohol was related to small ruptured aneurysms in men over 50 years of age (OR 2.23, 95% CI 1.03-4.84, p=0.042).

CONCLUSION

In this study, small (<5 mm) ruptured aneurysms exhibited different incidences by age, sex, location, and risk factors such as multiplicity, smoking, and alcohol use.

Accuracy in Identifying the Source of Subarachnoid Hemorrhage in the Setting of Multiple Intracranial Aneurysms

BACKGROUND

Subarachnoid hemorrhage cases with multiple cerebral aneurysms frequently demonstrate a hemorrhage pattern that does not definitively delineate the source aneurysm. In these cases, rupture site is ascertained from angiographic features of the aneurysm such as size, morphology, and location.

OBJECTIVE

To examine the frequency with which such features lead to misidentification of the ruptured aneurysm.

METHODS : Records of patients who underwent surgical clipping of a ruptured aneurysm at our institution between 2004 and 2014 and had multiple aneurysms were retrospectively reviewed. A blinded neuroendovascular surgeon provided the rupture source based on the initial head computed tomography scans and digital subtraction angiography images. Operative reports were then assessed to confirm or refute the imaging-based determination of the rupture source.

RESULTS

One hundred fifty-one patients had multiple aneurysms. Seventy-one patients had definitive hemorrhage patterns on initial computed tomography scans and 80 patients had nondefinitive hemorrhage patterns. Thirteen (16.2%) of the cases with nondefinitive hemorrhage patterns had discordance between the imaging-based determination of the rupture source and intraoperative findings of the true ruptured aneurysm, yielding an imperfect positive predictive value of 83.8%. Of all multiple aneurysm cases with subarachnoid hemorrhage treated by surgical or endovascular means at our institution, 4.3% (13 of 303) were misidentified.

CONCLUSION

Morphological features cannot reliably be used to determine rupture site in cases with nondefinitive subarachnoid hemorrhage patterns. Microsurgical clipping, confirming obliteration of the ruptured lesion, may be preferentially indicated in these patients unless, alternatively, all lesions can be contemporaneously and safely treated with endovascular embolization.

Irregular Shape Identifies Ruptured Intracranial Aneurysm in Subarachnoid Hemorrhage Patients With Multiple Aneurysms

BACKGROUND AND PURPOSE

We investigated which aneurysm-related risk factors for rupture best discriminate ruptured versus unruptured saccular intracranial aneurysms (sIAs) in subarachnoid hemorrhage patients with multiple sIAs.

METHODS

We included 264 subarachnoid hemorrhage patients with a ruptured sIA and at least one additional unruptured sIA, from the Kuopio Intracranial Aneurysm database from 2003 to 2015. These patients had 268 ruptured and 445 unruptured sIAs. Angiograms of the 713 sIAs were reevaluated for multiple variables describing aneurysm shape. Multivariate generalized linear mixed models were used to calculate odds ratios with corresponding 95% confidence intervals for the independent risk factors for aneurysm rupture.

RESULTS

In the multivariate analysis, only sIA size (P<0.004) and irregular shape (P<0.000) independently associated with sIA rupture. As an independent risk factor, irregular shape showed the strongest association with rupture (odds ratio 90.3; 95% confidence interval, 47.0-173.5). The sIA location, flow angles, bottleneck factor, or aspect ratio were not significantly associated with rupture.

CONCLUSIONS

Irregular shape may identify the ruptured sIA better than size in patients presenting with aSAH and multiple sIAs.

A Patient with Eight Intracranial Aneurysms: Endovascular Treatment in Two Sessions

The frequency of multiple intracranial aneurysms seen in patients with or without subarachnoid hemorrhage is high. The advancement of the endovascular technique and devices has ensured that endovascular treatment of intracranial aneurysms is the first choice in most cases, especially in unruptured ones. Different combinations of treatment modalities and techniques can be used in the management of multiple aneurysms. But in selected patients without subarachnoid hemorrhage, treatment of all aneurysms in one or more sessions with endovascular techniques is less traumatic than that with surgery. In the literature, the maximum number of aneurysms in one patient treated endovascularly and/or surgically is seven. In this case report, we present, with a review of the literature, a patient with eight intracranial aneurysms, all of which were treated in two sessions with various endovascular techniques. A 40-year-old female patient was admitted due to headache. Angiography showed eight aneurysms in the posterior circulation and, bilaterally, in the anterior circulation. All aneurysms were treated endovascularly in two sessions. In the treatment of the aneurysms, different endovascular techniques were used including flow diverters stents, stent-assisted coiling, Y-stent-assisted coiling, and coiling alone.

Patient and aneurysm characteristics associated with rupture risk of multiple intracranial aneurysms in the anterior circulation system

BACKGROUND

Multiple intracranial aneurysms (MIAs) are associated with poorer outcomes after rupture than are single intracranial aneurysms (SIAs). Although the risk factors for intracranial aneurysm rupture have been widely investigated, few studies have focused on MIAs. Thus, the present study aimed to determine whether there are differences in the patient and aneurysm characteristics between those with ruptured and unruptured anterior circulation MIAs (AC-MIAs).

METHOD

The present study included 97 patients with AC-MIAs (58 ruptured, 39 unruptured). Data regarding patient characteristics, aneurysm location, mirror aneurysms (MirAns), and bleb formations were collected from medical records and angiography images. Three-dimensional (3D) geometries generated with a 3D Slicer were evaluated to determine the range of morphological parameters. A univariate analysis was conducted to identify significant differences between the groups and receiver-operating characteristic (ROC) analyses were performed for each morphological parameter.

RESULTS

There are significantly fewer patients younger than 40 years of age in the ruptured group (P = 0.04); although the groups did not significantly differ with regard to smoking and hypertension, the ruptured group included significantly more current smokers who smoked more than 20 cigarettes per day (P = 0.025) and significantly more patients with a history of hypertension but an irregular use of anti-hypertensive medications (P = 0.043). Ruptured AC-MIAs were more likely to be located in the internal carotid artery (ICA) communicating artery (ICA C7) and anterior communicating artery (AComA; P = 0.000), to have formed a pair of MirAns (P = 0.001), and to have a bleb formation (P = 0.000). In terms of morphological parameters, the two groups differed significantly regarding aneurysm size (P = 0.000), neck width (P = 0.016), bottleneck factor (BNF; P = 0.000), height/width ratio (H/W; P = 0.031), aspect ratio (AR; P = 0.000) and size ratio (SR; P = 0.000). Additionally, the ROC analyses revealed that the optimal threshold size for rupture was 4.00 mm and that the SR had the highest area under the curve (AUC) value (0.826).

CONCLUSIONS

The present study found that current smokers who smoked more than 20 cigarettes per day and those with hypertension but an irregular use of anti-hypertensive medications were more likely to suffer from rupture. Aneurysm location and bleb formation were closely related to the rupture of AC-MIAs, and SR was a better predictor of AC-MIAs rupture status than size, neck width, BNF, H/W and AR. These findings should be verified by future prospective follow-up studies of AC-MIAs.

Contralateral Approach to Bilateral Middle Cerebral Artery Aneurysms: Comparative Study, Angiographic Analysis, and Surgical Results

BACKGROUND

Bilateral aneurysms located between the 2 middle cerebral artery (MCA) bifurcations may be approachable through a single unilateral approach.

OBJECTIVE

To identify anatomic parameters based on imaging that would favor a contralateral approach.

METHODS

From January 1998 to December 2013, we retrospectively identified 173 patients with bilateral intracranial aneurysms. Fifty-one patients had bilateral MCA aneurysms. A total of 38 patients underwent a single craniotomy with a contralateral microsurgical approach (group 1 or contralateral group) and 13 patients underwent bilateral craniotomies (group 2 or bilateral group). For both groups, we analyzed aneurysm characteristics, morphology, size, projections, and distance to the contralateral corridor, as well as surgical time, outcome, and postoperative complications.

RESULTS

All aneurysms approached contralaterally were unruptured and without wall calcifications. Of the contralaterally approached aneurysms, 97% were smaller than 14 mm. The median length of the contralateral A1 was 13.2 mm (range: 6-19.8 mm) and the median length of the contralateral M1 was 14.2 mm (range: 4.6-21 mm). The contralateral group had a good postoperative outcome (modified Rankin Scale 0-3) in 80% of ruptured cases and 86% of unruptured cases. The median surgical time was 120 minutes (range: 75-255 minutes), 43% shorter than the bilateral group.

CONCLUSION

The contralateral approach for bilateral MCA aneurysms in selected patients is feasible in experienced hands, with acceptable morbidity and mortality. The contralateral approach requires a meticulous preoperative analysis of the characteristics of the aneurysms to be clipped and of the anatomic constraints of the microsurgical operative corridor.

ABBREVIATIONS

A1, anterior cerebral artery proximal segmentbMCA, bilateral middle cerebral arteryCTA, computed tomographic angiographyHH, Hunt-Hess scaleIA, intracranial aneurysmsICA, internal carotid arteryICAbif, internal carotid artery bifurcationMCA, middle cerebral arteryM1, middle cerebral artery proximal segmentmRS, modified Rankin ScaleSAH, subarachnoid hemorrhage.

Contralateral Approach to Internal Carotid Artery Ophthalmic Segment Aneurysms: Angiographic Analysis and Surgical Results for 30 Patients

BACKGROUND

Contralateral aneurysm clipping can be applied to bilateral intracranial aneurysms of the anterior circulation and to selected aneurysms on the medial wall of the internal carotid artery (ICA).

OBJECTIVE

To identify anatomic and radiological parameters that would favor a contralateral microsurgical approach to ICA-ophthalmic segment (ICA-opht) aneurysms.

METHODS

For the period January 1957 to December 2012, we retrospectively analyzed 268 patients with ICA-opht aneurysms treated in our institution. Of these patients, 30 underwent a contralateral approach; 15 patients (50%) had multiple intracranial aneurysms, and 15 patients had a single aneurysm on the contralateral side of the craniotomy.

RESULTS

Thirty saccular aneurysms located on the contralateral ICA were treated. Six aneurysms (20%) were present in patients with a subarachnoid hemorrhage due to associated aneurysms, whereas 24 aneurysms (80%) had no history of bleeding. Contralateral aneurysms were smaller than 14 mm and showed no wall irregularities, calcifications, or secondary pouches. Projections of the aneurysms were superomedial (n = 23, 77%), medial (n = 4, 13%), and superior (n = 3, 10%). The median prechiasmatic distance was 5.7 mm (range, 3.4-8.7 mm), the median interoptic distance was 10.5 mm (range, 7.6-15.9 mm), and the median distance between both ICAs was 14.7 mm (range, 10.4-21.4 mm).

CONCLUSION

The contralateral approach for ICA-opht aneurysms remains a treatment option for intracranial aneurysms. Its feasibility depends on specific anatomic parameters related to the aneurysm itself and to the prechiasmatic distance, interoptic distance, and relationship of the ICA with the anterior clinoid process.

Endovascular management of adjacent tandem intracranial aneurysms: utilization of stent-assisted coiling and flow diversion

BACKGROUND

Tandem intracranial aneurysms are aneurysms located along a single intracranial vessel. Adjacent tandem aneurysms arise within the same vascular segment and their presence often suggests diffuse parent vessel anomaly. Endovascular management of these rare lesions has not been well studied. In this retrospective observational study, we describe our experience treating adjacent tandem intracranial aneurysms with endovascular embolization.

METHODS

We retrospectively reviewed records of patients with these lesions who underwent endovascular treatment between 2008 and 2013.

RESULTS

Thirteen patients (mean age 60.8 years; 12 women) with 28 adjacent tandem aneurysms were treated during the study timeframe. Aneurysms were located along the clinoidal, ophthalmic, and communicating segments of the internal carotid artery in 12 patients and at the basilar apex in one patient. Average size was 8.4 mm. Six patients (12 aneurysms) were treated by flow diversion via the Pipeline embolization device (PED) and seven (16 aneurysms) by stent-assisted coiling, with coils successfully placed in 11 aneurysms. Clinical follow-up was available for an average of 26.1 months; postprocedural angiography was performed for 12 patients. Complete occlusion was achieved in nine of ten (90 %) PED-treated aneurysms and eight of 11 (72.7 %) treated by stent-assisted coiling (p = 0.44). Two patients treated by stent-assisted coiling required re-coiling for aneurysm recanalization. Overall, modified Rankin scale scores were 0-1 for 12 patients and 3 for one patient.

CONCLUSIONS

Adjacent tandem intracranial aneurysms can be safely and effectively treated by either stent-assisted coiling or flow diversion. We prefer PED flow diversion due to better parent vessel reconstruction and lower recanalization risk.

Clinical characteristics and preferential location of intracranial mirror aneurysms: a comparison with non-mirror multiple and single aneurysms

INTRODUCTION

The purpose of our study was to compare the clinical characteristics and preferential localization of aneurysms in three patient groups: single aneurysm, non-mirror multiple aneurysms, and mirror aneurysms.

METHODS

We retrospectively reviewed the clinical and radiological data of 2223 consecutive patients harboring 3068 aneurysms registered at the Toronto Western Hospital between May 1994 and November 2010. The patients were divided into single, non-mirror multiple, or mirror aneurysm groups. Expected incidences of mirror aneurysms at each location were calculated on the basis of the single aneurysm incidences at each location.

RESULTS

Patients with mirror aneurysms (n = 197) did not differ from patients with non-mirror multiple aneurysms (n = 392) in having female predominance (81.7 vs. 76.3 %) or a family history of intracranial aneurysm (20.5 vs. 17.6 %). When compared with expected incidences at each location, mirror aneurysms were more frequently found at the cavernous internal carotid artery (30 vs. 11.5 %) (p < 0.0001). Mirror aneurysms involving the posterior circulation were less frequent (6.7 %) than aneurysms in the single (19.6 %) or non-mirror multiple aneurysm groups (18.9 %) (p < 0.05).

CONCLUSION

Patients with mirror aneurysms had similar clinical characteristics to non-mirror multiple aneurysm patients. Mirror aneurysms showed a predilection for the cavernous carotid artery, whereas they were comparatively rare in the posterior circulation.

Single-session Coil Embolization of Multiple Intracranial Aneurysms

OBJECTIVE

There is no clear treatment strategy for the management of multiple intracranial aneurysms because of variable anatomical distribution, difficult identification of the aneurysm ruptured, and poor overall outcomes. The purpose of this study was to assess the efficacy and safety of single-session coil embolization for multiple intracranial aneurysms.

METHODS

Between September 2008 and December 2012, 209 aneurysms in 117 patients were treated at our institute. Twenty eight among the 117 patients had multiple aneurysms with a total of 71, and 60 of the 71 aneurysms underwent coil embolization in a single-session.

RESULTS

A total of 60 aneurysms were treated with a single-session coil embolization, of which the most frequent locations were in the posterior communicating artery, followed by the middle cerebral artery. Immediate post-embolization angiographies showed total occlusion in 49 (81.7%) aneurysms, remnant neck in 6 (10%), and body-filling in 5 (8.3%). Procedure-related complications had developed in 2 (3.3%) of the 60 embolized aneurysms: an asymptomatic thromboembolic event, and a partial coil protrusion without a subsequent thromboembolic complication.

CONCLUSION

With careful evaluation of individual aneurysm characteristics and configuration, multiple intracranial aneurysms previously thought to require multimodality therapy can be safely treated in a single-session coil embolization.

Ruptured saccular aneurysm arising from fenestrated proximal anterior cerebral artery : case report and literature review

The aneurysm arising from fenestrated proximal anterior cerebral artery (ACA) is considered to be unique. The authors report a case of a 59-year-old woman who presented with a subarachnoid hemorrhage (SAH) secondary to a ruptured aneurysm originating from the fenestrated A1 segment of right ACA. The patient had another unruptured aneurysm which was located at the right middle cerebral artery bifurcation. She was successfully treated with surgical clipping for both aneurysms. From the previously existing literatures, we found 18 more cases (1983-2011) of aneurysms associated with fenestrated A1 segment. All cases represented saccular type of aneurysms, and 79% of the patients had SAH. There were three subtypes of the fenestrated A1 aneurysms depending on the anatomical location, relative to the fenestrated segment. The most common type was the aneurysms located on the proximal end of fenestrated artery (82%). Azygos ACA and hypoplastic A1 were frequently accompanied by the aneurysm (33% and 31%, respectively), and multiple aneurysms were shown in three cases (16%). Considering that fenestrated A1 segment is likely to develop an aneurysm, which has high risk of rupture, early management may benefit patients with aneurysms accompanied by fenestrated proximal ACA.

Multiple intracranial aneurysms associated with multiple dural arteriovenous fistulas and cerebral arteriovenous malformation

BACKGROUND

The association between intracranial aneurysms and arteriovenous malformations (AVMs) or dural arteriovenous fistulas (DAVFs) has been well documented, and the changes in cerebral blood flow dynamics were thought to be one of the major causes. There has not been a report on intracranial aneurysms associated with multiple DAVFs and AVMs in the same patient.

METHODS

The authors report a unique case of multiple intracranial vascular pathologies, including 5 aneurysms, 2 DAVFs, and 1 AVM coexisting in a single patient. The patient presented with headache and left hemiparesis and was found to have 4 bilateral internal carotid aneurysms, 1 ruptured right pericallosal aneurysm, 2 frontoparietal DAVFs, and 1 right temporal AVM.

RESULTS

Endovascular coiling and Onyx embolization successfully occluded 4 aneurysms and both DAVFs. The patient remained asymptomatic at 1-year follow-up.

CONCLUSIONS

To our knowledge, this is the first report of a very rare case with a unique combination of cerebrovascular pathologies including multiple aneurysms, DAVFs, and 1 high-grade AVM. Analyzing the hemodynamic relationships of these concurrent lesions is essential to determine the hemorrhage risk of each lesion and the order of priority in management. Flow-related aneurysms with irregular morphology require early, aggressive treatment.

Intracranial aneurysms: optimized diagnostic tools call for thorough interdisciplinary treatment strategies

OBJECTIVE

Intracranial aneurysms (IAs) require deliberately selected treatment strategies as they are incrementally found prior to rupture and deleterious subarachnoid haemorrhage (SAH). Multiple and recurrent aneurysms necessitate both neurointerventionalists and neurosurgeons to optimize aneurysmal occlusion in an interdisciplinary effort. The present study was conducted to condense essential strategies from a single neurovascular centre with regard to the lessons learned.

METHOD

Medical charts of 321 consecutive patients treated for IAs at our centre from September 2008 until December 2010 were retrospectively analysed for clinical presentation of the aneurysms, multiplicity and treatment pathways. In addition, a selective Medline search was performed.

RESULTS

A total of 321 patients with 492 aneurysms underwent occlusion of their symptomatic aneurysm: 132 (41.1%) individuals were treated surgically, 189 (58.2%) interventionally; 138 patients presented with a SAH, of these 44.2% were clipped and 55.8% were coiled. Aneurysms of the middle cerebral artery were primarily occluded surgically (88), whereas most of the aneurysms of the internal carotid artery and anterior communicating artery (114) were treated endovascularly. Multiple aneurysms (range 2-5 aneurysms/individual) were diagnosed in 98 patients (30.2%). During the study period 12 patients with recurrent aneurysms were allocated to another treatment modality (previously clip to coil and vice versa).

CONCLUSIONS

Our data show that successful interdisciplinary occlusion of IAs is based on both neurosurgical and neurointerventional therapy. In particular, multiple and recurrent aneurysms require tailored individual approaches to aneurysmal occlusion. This is achieved by a consequent interdisciplinary pondering of the optimal strategy to occlude IAs in order to prevent SAH.

Delayed diagnosis of aneurysmal subarachnoid hemorrhage in patients: a community-based study

OBJECT

A community-based study was conducted to estimate the frequency of and evaluate the clinical features related to delayed diagnosis of aneurysmal subarachnoid hemorrhage (SAH).

METHODS

Between 1980 and 1998, 358 patients with aneurysmal SAH underwent treatment in Izumo, Japan. The diagnosis of SAH was delayed in 76 patients (21%) and was early in 282 (79%). Among the 76 patients whose diagnosis was delayed, the condition was misdiagnosed by clinicians in 46 cases (Subgroup A), and in the remaining 30 the patients were unaware that SAH had occurred and failed to seek prompt treatment (Subgroup B).

RESULTS

The proportion of Subgroup A patients decreased significantly from 18% (30 of 170 patients) between 1980 and 1989 to 9% (16 of 188 patients) between 1990 and 1998 (p = 0.0098), whereas the proportion of Subgroup B patients during the same periods was 8% (13 of 170 patients) and 9% (17 of 188 patients), respectively (p = 0.6341). With regard to Subgroup A, the misdiagnosis rate in private clinics decreased from 14% (23 of 170 patients) between 1980 and 1989 to 5% (10 of 188 patients) between 1990 and 1998 (p = 0.0073), whereas the misdiagnosis rate in hospitals during the same periods was 4% (7 of 170 patients) and 3% (6 of 188 patients), respectively (p = 0.6399). Multivariate analysis revealed that World Federation of Neurosurgical Societies Grade I or II was the main risk factor for delayed diagnosis of SAH (OR 3.97 [95% CI 1.69-10.37]), and that the timing of SAH onset, that is, between 12:00 a.m. and 6:00 a.m., was an important reason for the condition in Subgroup B patients (OR 9.29 [95% CI 2.66-33.93]). Rebleeding before admission occurred in 26% of the patients in whom diagnosis was delayed, and in 3% of those who were diagnosed early (p < 0.0001).

CONCLUSIONS

Although the rate of SAH misdiagnosis seems to be decreasing, failure of patients to present for prompt treatment is unlikely to decrease unless the public becomes better educated about SAH and the importance of getting prompt medical attention, even in the middle of the night.