Risk factors for multiple intracranial aneurysms rupture: a retrospective study

Identifying hemodynamic factors associated with the rupture of anterior communicating artery aneurysms based on global modeling of blood flow in the cerebral artery network

Anterior communicating artery (ACoA) aneurysms are more prone to rupture compared to aneurysms present in other cerebral arteries. We hypothesize that systemic blood flow in the cerebral artery network plays an important role in shaping intra-aneurysmal hemodynamic environment thereby affecting the rupture risk of ACoA aneurysms. The majority of existing numerical studies in this field employed local modeling methods where the physical boundaries of a model are confined to the aneurysm region, which, though having the benefit of reducing computational cost, may compromise the physiological fidelity of numerical results due to insufficient account of systemic cerebral arterial hemodynamics. In the present study, we firstly carried out numerical experiments to address the difference between the outcomes of local and global modeling methods, demonstrating that local modeling confined to the aneurysm region results in inaccurate predictions of hemodynamic parameters compared with global modeling of the ACoA aneurysm as part of the cerebral artery network. Motivated by this finding, we built global hemodynamic models for 40 ACoA aneurysms (including 20 ruptured and 20 unruptured ones) based on medical image data. Statistical analysis of the computed hemodynamic data revealed that maximum wall shear stress (WSS), minimum WSS divergence, and maximum WSS gradient differed significantly between the ruptured and unruptured ACoA aneurysms. Optimal threshold values of high/low WSS metrics were determined through a series of statistical tests. In the meantime, some morphological parameters of aneurysms, such as large nonsphericity index, aspect ratio, and bottleneck factor, were found to be associated closely with aneurysm rupture. Furthermore, multivariate logistic regression analyses were performed to derive models combining hemodynamic and morphological parameters for discriminating the rupture status of aneurysms. The capability of the models in rupture status discrimination was high, with the area under the receiver operating characteristic curve reaching up to 0.9. The findings of the study suggest that global modeling of the cerebral artery network is essential for reliable quantification of hemodynamics in ACoA aneurysms, disturbed WSS and irregular aneurysm morphology are associated closely with aneurysm rupture, and multivariate models integrating hemodynamic and morphological parameters have high potential for assessing the rupture risk of ACoA aneurysms.

Unilateral approach for bilateral clipping of posterior communicating artery aneurysms in a hybrid operating room: A technical note

Bilateral posterior communicating (pComm) artery aneurysms represent only 2% of mirror intracranial aneurysms. Usually, these are surgically approached through bilateral craniotomies for clipping. We present the case of a 50-year-old female presenting with headache and horizontal diplopia. Neurological examination revealed a left oculomotor palsy, with no other neurological deficits. Imaging studies revealed bilateral aneurysmatic lesions in both internal carotid arteries (ICA). A conventional left pterional approach was planned in order to treat the symptomatic aneurysm, and, if deemed feasible, a contralateral clipping through the same approach. The procedure was performed in a hybrid operating room (HOR), performing an intraoperative digital subtraction angiography (DSA) and roadmapping assistance during dissection and clipping. Transoperatively, a post-fixed optic chiasm was identified, with a wide interoptic space, which allowed us to perform the contralateral clipping through a unilateral approach. This technique for clipping bilateral pComm aneurysms can be performed when the proper anatomical features are met.

Unruptured Anterior Communicating Artery Aneurysms: Management Strategy and Results of a Single-Center Experience

Although anterior communicating artery (AComA) unruptured intracranial aneurysms (UIAs) comprise one of the largest aneurysm subgroups, their complex adjacent neurovasculature and increased risk of rupture impede optimal management. In the present study, we analyzed the results of our diverse strategy in AComA UIAs with the additional goal of assessing the risk of treatment and the incidence of hemorrhage. We analyzed 131 patients, of which each was assessed by a multidisciplinary neurovascular team and assigned to observation (45.8%), endovascular treatment (34.4%) or microsurgery (19.8%). Median aneurysm sizes were 3, 7.2 and 7.75 mm, respectively. In the observation group, four (7.1%) aneurysms (initially <5 mm) grew over a median time of 63.5 months and were treated endovascularly. We found that fewer patients in the observation group were smokers (p = 0.021). The aneurysm size ratio was different between the combined treatment versus the observation group (p < 0.0001). Noteworthily, there were no hemorrhages in the observational group. Mortality for all patients with available follow-up was 2.4% (3/124) and permanent morbidity was 1.6% (2/124) over a mean follow-up of 64.2 months. These compelling rates refer to a high-risk group with potentially devastating consequences in which we have decreased the annual risk of hemorrhage to 0.14%.

Hemodynamic indicators of the formation of tandem intracranial aneurysm based on a vascular restoration algorithm

Background

Hemodynamic factors are believed to be closely related to IA growth. However, the underlying pathophysiological mechanism that induces the growth sequence in tandem intracranial aneurysms (IAs) remains unclear.

Methods and results

This study involved five patients with tandem IAs. Aneurysm models were reconstructed based on image datasets. A novel vascular restoration algorithm was proposed to generate the hypothetical geometry of the healthy parent vessel before each IA formation in the concatenated structure. Detailed hemodynamic patterns and morphological features were revealed under various growth sequences of tandem IAs to investigate the flow-driven mechanism of IA growth. Potential hemodynamic indicators of IA formation were proposed.

Results

The patient cases were divided into two groups based on the size difference of tandem IAs. In the group with a similar size of tandem IAs, the position of the vortex core was associated with the site of the secondary aneurysm, while in the group with a significant size difference of the IAs, the position with the maximum curvature of the parent vessel plays a significant role in aneurysm formation.

Conclusions

This study preliminarily revealed key hemodynamic and morphological indicators that determine the formation of tandem IAs. The proposed vascular restoration algorithm that provided the pre-aneurysm vasculature might be useful in investigating the flow-driven mechanism of IA growth, thus contributing to the risk evaluation of secondary aneurysm formation.

Risk factors for anterior communicating artery aneurysm rupture: A protocol for systematic review and meta-analysis

BACKGROUND

Although the research on the risk factors of anterior communicating artery (AComA) aneurysm has made great progress, the independent effect of each risk factor on the rupture of AComA aneurysm is controversial among different studies. We will perform a protocol for systematic review and meta-analysis to investigate risk factors for AComA aneurysm rupture and quantify their independent effects.

METHODS

A systematic search according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols guidelines in PubMed, Embase, and the Cochrane Library databases was conducted from inception to August 31, 2021 for published studies concerning risk factors for AComA aneurysm rupture. In the absence of statistical heterogeneity (ie, P > .10 and I2 < 50%), we will use a fixed-effects model to pool the results across sufficient studies. Otherwise, we will present the results employing the random-effects model. Quality assessment of the included studies will be evaluated using the Newcastle-Ottawa Scale. Statistical analyses will be performed using Stata16 (Stata Corporation, College Station, TX, USA) software.

RESULTS

The findings of this study will be submitted to peer-reviewed journals for publication.

CONCLUSION

This systematic review will provide evidence to determine the risk factors that affect the rupture of the AComA aneurysm and quantify their independent effects.

ETHICS AND DISSEMINATION

Since the proposed study uses pre-published data, ethical approval is not required.

REVIEW REGISTRATION NUMBER

CRD42021284262. (https://www.crd.york.ac.uk/PROSPERO/).

Endovascular Treatment of Intracranial Kissing Aneurysms: Technical Feasibility and Clinical Outcomes

BACKGROUND

Kissing aneurysms are situated on the same artery but have separate points of origin. Open surgical strategies for access from opposing directions may be technically problematic. Recent advances in protective devices and coiling techniques have compelled the present study, aimed at technical aspects and procedural outcomes of coil embolization in this setting.

METHODS

Data prospectively accruing between May 2001 and May 2020 were systematically reviewed, assessing clinical and morphologic outcomes of coil embolization in 36 patients with 72 kissing aneurysms.

RESULTS

Lesions most often involved paraclinoid internal carotid artery (n = 22), followed by anterior communicating artery (n = 7). Single-stage coil embolization of both aneurysms took place in nearly all patients (n = 35). Microcatheter tips for selecting paired aneurysms were usually directed opposite to one another (32 of 36, 88.9%), applying protective devices (i.e., balloons or stents) to 1 or both aneurysms in 21 patients (58.3%). Balloons were placed in 9 patients, often when treating first aneurysms and largely for second aneurysms as well (7 of 9, 77.8%). Stents deployed in 14 patients involved first and second aneurysms equally. Two patients required balloon of stent combinations. No procedure-related morbidity or mortality resulted. In follow-up of 68 aneurysms (mean: 40.2 ± 28.1 months) after coiling, 86.8% (59 of 68) showed sustained complete saccular occlusion.

CONCLUSIONS

Strategies for endovascular treatment of kissing aneurysms rely heavily on characteristics that the paired aneurysms display. Properly conducted single-stage coil embolization is a safe and effective method of treating such lesions.

Analysis of Risk Factors for Anterior Communicating Artery Aneurysm Rupture: A Single-Center Study

BACKGROUND

Congenital hypoplasia or aplasia of the A1 segment of the anterior cerebral artery is associated with an increased incidence of berry aneurysms at the anterior communicating artery (ACoA) complex. We analyzed the factors contributing to ACoA aneurysm rupture.

METHODS

We retrospectively analyzed the data of patients with ACoA aneurysms who had undergone cerebral angiography from July 2008 to January 2020. The risk factors for rupture were identified using univariate and multivariate logistic regression models. We used the imaging data of patients without intracranial aneurysms as the control population.

RESULTS

We confirmed 253 aneurysms in 253 patients, including 137 men (54.2%) and 116 women (45.8%), with a mean age of 54.6 ± 12.7 years. Of the 253 aneurysms, 218 (86.2%) were ruptured and 35 (13.8%) were unruptured, with a mean diameter of 4.56 ± 1.96 mm and 3.24 ± 1.79 mm, respectively. Of the 253 aneurysms, 176 (69.6%) were <5 mm in diameter, 146 (83%) of which were ruptured. Of the 253 patients, 141 (55.7%) exhibited A1 segment hypoplasia or aplasia: 106 (41.9%) on the right side of the circle of Willis and 35 (13.8%) on the left. Multivariate logistic regression analysis identified the aneurysm diameter (odds ratio, 4.11; 95% confidence interval, 1.601-16.07; P = 0.003) and age <65 years (odds ratio, 0.17; 95% confidence interval, 0.062-0.48; P < 0.001) as independent predictors of rupture.

CONCLUSIONS

ACoA aneurysms are small (<5 mm) and have a high risk of rupture. A1 segment hypoplasia or aplasia is a risk factor for ACoA aneurysm formation; however, it was uncorrelated with aneurysm diameter or rupture risk. The strongest independent risk factors for rupture were age <65 years and aneurysm diameter.

Predictors of Outcome Following Interventions for Ruptured Intracranial Aneurysms in an Emerging Health Institution in West Bengal: A 6-Year Experience

Background:

Microsurgical clipping and endovascular coiling have remained over the past half-century, the main options for definitive treatment of ruptured intracranial aneurysms. However, recent advances in endovascular techniques have broadened their application stimulating much debate regarding the usefulness of microsurgical options. For locations with limited capacity or evolving endovascular service, however, microsurgical treatment offers not only cost-effective and durable options but also oftentimes the only option available for most patients.

Materials and Methods:

This was a single institution questionnaire-based retrospective study from West Bengal India. It was performed on patients with aneurysmal rupture managed from June 2010 to October 2016. Data analysis was performed with SPSS for Windows, version 21.

Results:

One hundred and ten patients were studied. The mean age was 50.8 years (standard deviation [SD] ±13.5) for females and 50.2 (SD ± 12.4) for males (P = 0.8112, t-test). Ninety (81.8%) patients received microsurgical clipping. Microsurgical options such as wrapping, bypass, and excision were performed for 9 (8.2%) patients. Coiling was performed for 11 (10%) patients. ACOM was the most common site for ruptured aneurysm. Ictus-intervention interval (χ₂ = 10.034, P = 0.007) and multiple surgical procedures (χ₂ = 8.9341, P = 0.003) were the significant outcome determinants. Overall, 72.7% of those treated had a good outcome (Glasgow Outcome Score of 4 and 5). The good outcome was higher among microsurgery groups (73.7%) compared to the coiling group (63.6%) but this difference did not achieve statistical significance (χ₂ = 0.46 P = 0.4976).

Conclusion:

Microsurgical options achieved good outcomes in the management of ruptured aneurysms in our series. Their availability makes them first-line options for low-income settings.

Clinical Characteristics of Ruptured Intracranial Aneurysm in Patients with Multiple Intracranial Aneurysms

OBJECTIVE

It is difficult to correctly identify the ruptured aneurysm in patients with multiple intracranial aneurysms. Here, we investigated the clinical characteristics of ruptured intracranial aneurysms in such patients.

METHODS

We retrospectively analyzed 361 patients who underwent microsurgical clipping of ruptured intracranial aneurysms at our institution from 2012 to 2018. Patients' age, sex, Fisher group, World Federation of Neurosurgical Societies grade, size (neck width, depth, maximum diameter), location, and shape of intracranial aneurysm, and hemorrhage pattern on admission were reviewed.

RESULTS

In total, 266 patients (74%) had single intracranial aneurysms and 95 (26%) had multiple intracranial aneurysms. Eighty-nine of the 95 multiple intracranial aneurysms (94%) had irregular shape (P < 0.01). The median aspect ratios of ruptured and unruptured intracranial aneurysms were 2.2 ± 1.1 and 1.0 ± 0.4, respectively (P < 0.01). Twelve of 95 patients (13%) had ruptured intracranial aneurysms that were smaller than unruptured intracranial aneurysms. Among the 12 patients, the aspect ratios of ruptured intracranial aneurysms were greater than those of unruptured intracranial aneurysms (P < 0.01). Regarding morphologic characteristics, aspect ratio, maximum size, and irregular shape could be the useful predictive factors, but the greatest aspect ratio among patients with multiple aneurysms was the most predictive of an intracranial aneurysm rupture, after adjustment for aneurysmal size (adjusted odds ratio 217.82; 95% confidence interval 56.41-841.08).

CONCLUSIONS

The results of this study indicate that the aspect ratio is the most predictive factor of a ruptured intracranial aneurysm in patients with multiple intracranial aneurysms.

One-stage coiling versus clipping of multiple intracranial aneurysms in elderly patients

OBJECTIVES

Although multiple intracranial aneurysms (MIAs) are frequent and disastrous, determining treatment strategy for them is often complicated, especially in elderly patients (≥60 years old). We evaluated the safety and effectiveness of one-stage coiling versus surgical clipping for MIAs in elderly patients.

METHODS

All elderly patients who underwent one-stage embolization or surgical clipping for more than two aneurysms were identified in our hospital between January 2012 and June 2018. Patient characteristics and clinical outcomes at discharge and follow-up were retrospectively evaluated.

RESULTS

A total of 32 patients with 76 IAs underwent one-stage coiling and 21 patients with 46 IAs underwent one-stage clipping were enrolled in this study. Patients who underwent clipping were younger (mean age 64.1 versus 67.2, P = 0.006) and had lower total hospital costs (mean14764 $ versus 24,620 $, P < 0.001) compared with patients who underwent coiling. Immediate posttreatment angiography showed complete occlusion in 56 aneurysms, near complete in 11 and incomplete in 2 in coiling group. Aneurysms wrapping was performed in 2, incomplete clipping in 1 and complete clipping in 41 aneurysms in clipping group. At discharge, 49 (92.5 %) patients were in a good condition (GOS score 4 and 5), 4 (7.5 %) were disabled. At 12 months after discharge, 25 (92.6 %) and 16 (94.1 %) patients had favorable outcomes in the coiling and clipping groups, respectively.

CONCLUSIONS

Both one-stage coiling and surgical clipping are safe, effective methods for treating MIAs in elderly patients.

Clinical evaluation of subtracted pointwise encoding time reduction with radial acquisition-based magnetic resonance angiography compared to 3D time-of-flight magnetic resonance angiography for improved flow dephasing at 3 Tesla

OBJECTIVE

Flow dephasing artifacts within intracranial internal carotid artery (ICA) have been problematic for 3D time-of-flight magnetic resonance angiography (3D-TOF-MRA). This study aimed to evaluate pointwise encoding time reduction with radial acquisition subtraction-based MR angiography (PETRA-MRA) for decreasing flow dephasing artifacts compared to 3D-TOF-MRA in intracranial segments of ICA at 3 T.

METHODS

Sixty healthy participants and seven patients with intracranial ICA aneurysms were enrolled to undergo 3D-TOF-MRA and PETRA-MRA. Two radiologists each evaluated the image quality of healthy participants using a 4-point scale (1: the best and 4: the worst). Quantitative analysis of the extent of homogeneity in signal intensity within the ICA and intracranial aneurysms was conducted using a parameter d: the higher the d value, the greater the signal homogeneity. Wilcoxon signed rank test, Chi-square test and the weighted kappa (κ) statistic were used for statistical analyses.

RESULTS

The image quality of PETRA-MRA with an overall score of 1.35 ± 0.53 was significantly better than that obtained with 3D-TOF-MRA, with an overall score of 3.50 ± 0.62 (Z = -9.56, p < 0.001). The parameter d of PETRA-MRA was higher than that of 3D-TOF-MRA for both 60 healthy participants (0.97 ± 0.05, 0.87 ± 0.11; z = -13.21, p < 0.001) and 7 patients with intracranial aneurysms (0.81 ± 0.18, 0.74 ± 0.16; z = -2.37, p = 0.018).

CONCLUSION

Compared with conventional 3D-TOF-MRA, PETRA-MRA remarkably improved the image quality with reduced flow dephasing artifacts in segments of intracranial ICA.

Pointwise encoding time reduction with radial acquisition in subtraction-based magnetic resonance angiography to assess saccular unruptured intracranial aneurysms at 3 Tesla

PURPOSE

To investigate the clinical utility of pointwise encoding time reduction with radial acquisition in subtraction-based magnetic resonance angiography (PETRA-MRA) and time-of-flight magnetic resonance angiography (TOF-MRA) to evaluate saccular unruptured intracranial aneurysms (UIAs).

METHODS

A total of 49 patients with 54 TOF-MRA-identified saccular UIAs were enrolled. The morphologic parameters, contrast-to-noise-ratios (CNRs), and sharpness of aneurysms were measured using PETRA-MRA and TOF-MRA. Two radiologists independently evaluated subjective image scores, focusing on aneurysm signal homogeneities and sharpness depictions using a 4-point scale: 4, excellent; 3, good; 2, poor; 1, not assessable. PETRA-MRA and TOF-MRA acoustic noises were measured.

RESULTS

All aneurysms were detected with PETRA-MRA. The morphologic parameters of 15 patients evaluated with PETRA-MRA were more closely correlated with those receiving computed tomography angiography over those receiving TOF-MRA. No significant differences between PETRA-MRA and TOF-MRA parameters were seen in the 54 UIAs (p > 0.10), excluding those with inflow angles (p < 0.05). In four patients with inflow angles on PETRA-MRA, the angles were more closely related to those of digital subtraction angiography than those of TOF-MRA. CNRs between TOF-MRA and PETRA-MRA were comparable (p = 0.068), and PETRA-MRA sharpness values and subjective image scores were significantly higher than those of TOF-MRA (p < 0.001). Inter-observer agreements were excellent for both PETRA-MRA and TOF-MRA (intraclass correlation coefficients were 0.90 and 0.97, respectively). The acoustic noise levels of PETRA-MRA were much lower than those of TOF-MRA (59 vs.73 dB, p < 0.01).

CONCLUSIONS

PETRA-MRA, with better visualization of aneurysms and lower acoustic noise levels than TOF-MRA, showed a superior diagnostic performance for depicting saccular UIAs.

A predictive score for identification of rupture site in subarachnoid haemorrhage with multiple intracranial aneurysm

PURPOSE

The rigid method of identifying the rupture site in cases of subarachnoid haemorrhage (SAH) with multiple intracranial aneurysms (MIAs) is still unclear. Here we present a reliable method by using a combination of six predictors.

MATERIALS AND METHODS

Concerning the 48 SAH patients with MIAs who visited the Showa General Hospital during the period from January 2005 to March 2016, several predictors of rupture site such as the aneurysm-related morphologic features (size, aspect ratio, shape, bleb), aneurysm location, and the distribution of SAH were investigated. Compared with other coexisting aneurysms in each predictor, each aneurysm was categorized into 'suspicion' or 'non-suspicion', and we analyzed the association between 'suspicion' and rupture.

RESULTS

In the first analysis, all variables were associated with rupture and included in the multivariate logistic regression analysis. The presence of bleb (OR, 20.7; CI, 2.3-186; p = .007) and the aneurysm location (OR, 23.5; CI, 5.2-106; p < .001) were significantly associated with rupture in multivariate logistic regression analysis. Based on the results, a predictive score for rupture was created and calculated for each aneurysm, and the aneurysm with highest predictive score in each patient was categorized into 'suspicion'. 'Suspicion' in the predictive score was significantly associated with rupture (OR, 412.5; CI, 52.2-16384; p < .001). The sensitivity (0.90), specificity (0.98) and the accuracy (0.94) of identifying the rupture site by the predictive score were quite satisfactory.

CONCLUSION

Our results suggest that the predictive score may be an excellent parameter to identify the rupture site in cases of SAH with MIAs.

One-stage Operation with Ipsilateral Two-Piece Craniotomies for a Case of Subarachnoid Hemorrhage with Multiple Intracranial Aneurysms

Subarachnoid hemorrhage (SAH) with multiple intracranial aneurysms is common, but the difficulties often arise in determining treatment strategy in the acute phase. We experienced a case of SAH with distal anterior cerebral artery aneurysm coexisting with middle cerebral artery and anterior communicating artery aneurysms, in which it was difficult to identify the precise rupture site preoperatively, and both pterional approach and interhemispheric approach were required in the acute phase of SAH. However, we could treat whole aneurysms in one stage and obtained an excellent outcome using our surgical procedure with ipsilateral frontotemporal and frontal parasagittal craniotomies through a single skin incision.

Safety and Efficacy of Bilateral Flow Diversion for Treatment of Anterior Circulation Cerebral Aneurysms

BACKGROUND

Nearly 20% of individuals with an aneurysm will have multiple aneurysms-these individuals are at increased risk of subarachnoid hemorrhage. Treatment of bilateral aneurysms with flow diverters (FDs), or Pipeline embolization device, has not yet been established as an effective therapy. We evaluated the safety and efficacy of a 2-stage treatment of bilateral aneurysms with Pipeline embolization devices placed 6 months apart.

METHODS

We performed a retrospective review to analyze the clinical and angiographic outcomes of 16 individuals with bilateral aneurysms treated with 2-stage flow diversion at a tertiary referral center from January 2010 to July 2018.

RESULTS

Of the 16 patients with 33 aneurysms treated with bilateral flow diversion, 1 had 2 aneurysms treated with a single FD on the contralateral side. The aneurysms treated were ophthalmic, superior hypophyseal, posterior communicating, or cavernous segment aneurysms, with an average size of 6.5 mm. No major complications, such as in-stent stenosis, thromboembolic events, distal intraparenchymal hemorrhage, rerupture, stent migration, or neurological death, were recorded. All the patients had good functional outcomes. At the 24-month follow-up examination, 81% of aneurysms showed complete occlusion. No aneurysm required repeat treatment.

CONCLUSIONS

The results from the present study have demonstrated that 2-stage treatment of bilateral aneurysms with FDs is both safe and efficacious. The timing of contralateral FD stent placement is critical. We found that 6 months allows for adequate neurological recovery and stent endothelialization.

Concomitant ruptured anterior circulation and unruptured posterior circulation aneurysms: Treatment strategy and review of literature

Basilar artery apex or bifurcation is the most common location for aneurysms arising from posterior cerebral circulation. Reports of unruptured aneurysms of the basilar bifurcation associated with ruptured anterior circulation aneurysms are rare. The presence of multiple intracranial aneurysms poses a significantly high risk to management than a single aneurysm due several factors involved. Surgical management is considered the best treatment modality for most aneurysmal types and location with quite a few limitations when applicable. Authors have conducted a literature review of anterior and posterior circulation concomitant aneurysms and report their own experience with a case of anterior communicating artery blister type aneurysmal rupture presented with the symptoms and signs of subarachnoid hemorrhage concomitant with an unruptured basilar artery bifurcation aneurysm. Moreover, the anomalous origin of thalamoperforators at the basilar apex instead of the posterior cerebral artery makes it reasonably challenging for the microsurgical clipping. Discussed is the clinical presentation, radiological studies obtained, surgical approach utilized with an adequate exposure of the entire circle of Willis as well as the critical decision making when managing these challenging cases.

Meta-Analysis of Clipping versus Coiling for the Treatment of Unruptured Middle Cerebral Artery Aneurysms: Direct Comparison of Procedure-Related Complications

BACKGROUND

Endovascular coiling and surgical clipping are routinely used to treat unruptured middle cerebral artery aneurysms (MCAAs). However, the optimal treatment for unruptured MCAAs is controversial. We aimed to systematically and comprehensively compare the clinical outcomes between endovascular coiling and surgical clipping for the treatment of MCAAs.

METHOD

This meta-analysis retrieved academic articles comparing the clinical outcomes between endovascular coiling and surgical clipping for unruptured MCAAs from the Cochrane Library, Medline, PubMed, and EMBASE databases. The reference articles of the identified studies were carefully reviewed to ensure that all available articles were represented in the study. The meta-analysis was conducted in accordance with the acknowledged the prioritized reported items for systematic review and meta-analysis (PRISMA) guidelines.

RESULTS

A total of 6 studies, which enrolled a total of 789 participants, were included in our analysis. Of these 789 patients with MCAAs, 144 were assigned to an endovascular coiling group, and 645 were assigned to a surgical clipping group. Our results demonstrated that endovascular coiling was associated with a higher rate of retreatment (OR = 104.926; 95% CI: 12.931 to 851.379; P<0.001) and postoperative complications (OR = 3.157; 95% CI: 1.239 to 8.048; P= 0.016) than surgical clipping, especially for postoperative thrombus without infarction (OR = 4.905, 95% CI: 1.097 to 21.933; P = 0.037). Furthermore, surgical clipping was related to a higher rate of complete occlusion (OR = 0.349, 95% CI: 0.140 to 0.872; P = 0.024) and Glasgow Outcome Scale (GOS) ≥4 (OR = 0.250; 95% CI: 0.072 to 0.867; P= 0.029) than endovascular coiling after the operation. However, there was no significant difference in the rate of death, the proportion of patients with modified Rankin Scale (mRS)>2, infarction, or bleeding.

CONCLUSION

Although this study has inherent limitations, surgical clipping of unruptured MCAAs resulted in significantly higher complete aneurysm occlusion and GOS≥4 rates and was associated with a lower incidence of retreatment and complication, especially for postoperative thrombus without infarction. Therefore, the effect induced by surgical clipping of unruptured MCAAs remains superior to that induced by endovascular coiling; surgical clipping should be regarded as the first choice of treatment for unruptured MCAAs.

Intracranial Mirror Aneurysms: Anatomic Characteristics and Treatment Options

Objective

Mirror aneurysms are generally considered as a subset of multiple aneurysms, defined as aneurysms occurring bilaterally and symmetrically on the same-named vessels. Although not infrequent, the characteristics of mirror aneurysms are not well studied. This investigation was conducted to elucidate the anatomic features of such lesions and examine treatment options.

Materials and Methods

A retrospective review was conducted, aimed at 172 patients treated for 344 mirror aneurysms between January 2007 and December 2015. Aneurysms of similar nature but in asymmetric locations on the same-named vessels were excluded. All available records were examined and lesion characteristics, as well as treatment outcomes were assessed.

Results

In study subjects (n = 172), mirror aneurysms most often involved middle cerebral artery bifurcation (n = 83), followed by a paraclinoid internal carotid artery (n = 50) and posterior communicating artery (n = 21). Most of the lesions (95.3%) measured ≤ 10 mm, and in 126 patients (74.6%), the size ratios were > 50%. Of the 344 aneurysms studied, coil embolization was undertaken in 217, surgical clipping in 62, and observation alone (no treatment) in 65. Coil embolization and surgical clipping were done bilaterally in 83 and 12 patients, respectively. In 12 patients, combined coiling and clipping were implemented on each side. Single-stage coil embolization of both the aneurysms was performed in 73 patients, with excellent post-procedural (85.6%) and follow-up (86.8%) occlusive results. There was no procedure-related morbidity or mortality.

Conclusion

By adopting different treatment strategies to different configurations and vascular sources, mirror aneurysms can be safely and effectively treated. If feasible, single-stage coil embolization should be considered as a reasonable treatment option for mirror aneurysms.

Morphological Parameters Related to Aneurysm Wall Enhancement in Patients with Multiple Intracranial Aneurysms

BACKGROUND

Vessel wall magnetic resonance imaging (MRI) has been suggested as a potential in vivo method to detect inflammation of aneurysm wall and identify unruptured intracranial aneurysm (UIA) at high risk for rupture. This study aims to investigate the correlation between aneurysm wall enhancement (AWE) on vessel wall MRI and rupture-related morphological parameters in patients with multiple UIAs.

METHODS

Clinical data and vessel wall MRI images were reviewed in 14 patients with 30 multiple UIAs. The AWE was defined as enhancement of the aneurysm wall in postcontrast vessel wall MRI using the precontrast MRI as a reference. Morphological parameters, including aneurysm size, aspect ratio, size ratio, bottleneck factor, height-to-width ratio, nonsphericity index (NSI), and inflow angle, were measured using 3-dimensional rotation angiography. Univariate and multivariate analyses were performed to evaluate the correlations between morphological parameters and the presence of AWE.

RESULTS

Sixteen of the 30 multiple UIAs presented with AWE on vessel wall MRI. On univariate analyses, UIAs with AWE were significantly larger (P = 0.001) and had significantly higher aspect ratio (P = 0.047), size ratio (P = 0.003), bottleneck factor (P = 0.007), and NSI (P = 0.007) values. Further multivariate logistic regression showed that aneurysm size (odds ratio, 3.54; 95% confidence interval, 1.10-11.35; P = 0.033) and NSI (odds ratio, 3.53; 95% confidence interval, 1.06-11.80; P = 0.040) were independently associated with the presence of AWE in multiple UIAs.

CONCLUSIONS

The presence of AWE on vessel wall MRI was significantly correlated with conventional morphological rupture risk factors in patients with multiple UIAs, which might indicate AWE as a potential radiologic predictor for UIAs with high rupture risk.

Hemodynamic Characteristics of Ruptured and Unruptured Multiple Aneurysms at Mirror and Ipsilateral Locations

BACKGROUND AND PURPOSE

Different hemodynamic patterns have been associated with aneurysm rupture. The objective was to test whether hemodynamic characteristics of the ruptured aneurysm in patients with multiple aneurysms were different from those in unruptured aneurysms in the same patient.

MATERIALS AND METHODS

Twenty-four mirror and 58 ipsilateral multiple aneurysms with 1 ruptured and the others unruptured were studied. Computational fluid dynamics models were created from 3D angiographies. Case-control studies of mirror and ipsilateral aneurysms were performed with paired Wilcoxon tests.

RESULTS

In mirror pairs, the ruptured aneurysm had more oscillatory wall shear stress (P = .007) than the unruptured one and tended to be more elongated (higher aspect ratio), though this trend achieved only marginal significance (P = .03, 1-sided test). In ipsilateral aneurysms, ruptured aneurysms had larger maximum wall shear (P = .05), more concentrated (P < .001) and oscillatory wall shear stress (P < .001), stronger (P < .001) and more concentrated inflow jets (P < .001), larger maximum velocity (P < .001), and more complex flow patterns (P < .001) compared with unruptured aneurysms. Additionally, ruptured aneurysms were larger (P < .001) and more elongated (P < .001) and had wider necks (P < .001) and lower minimum wall shear stress (P < .001) than unruptured aneurysms.

CONCLUSIONS

High wall shear stress oscillations and larger aspect ratios are associated with rupture in mirror aneurysms. Adverse flow conditions characterized by high and concentrated inflow jets; high, concentrated, and oscillatory wall shear stress; and strong, complex and unstable flow patterns are associated with rupture in ipsilateral multiple aneurysms. In multiple ipsilateral aneurysms, these unfavorable flow conditions are more likely to develop in larger, more elongated, more wide-necked, and more distal aneurysms.

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.

Exploring potential association between flow instability and rupture in patients with matched-pairs of ruptured-unruptured intracranial aneurysms

Background

Patients with multiple intracranial aneurysms present a great challenge to the neurosurgeon, particularly when presenting with subarachnoid hemorrhage. Misjudgment may result in disastrous postoperative rebleeding from the untreated but true-ruptured lesion.

Methods

In this study, computational fluid dynamic simulations of two matched-pairs of ruptured–unruptured cerebral aneurysms were performed to investigate the potential association between flow instability and aneurysm rupture. Two pairs of cerebral aneurysms from two patients were located in the middle cerebral artery and the anterior communicating artery respectively.

Results

Our results demonstrated highly disturbed states of the blood flows in the ruptured aneurysms of the two patients with multiple aneurysms, which are characterized by remarked velocity and wall shear stress (WSS) fluctuations at late systole. The ruptured aneurysms exhibit obviously temporal intra-cycle WSS fluctuations rather than the unruptured aneurysms of the same patient. Cycle-to-cycle fluctuations are further observed in the ruptured aneurysms when the flow turns to decelerate.

Conclusions

The obvious differences observed between matched-pairs of ruptured–unruptured aneurysms imply that flow instability may be a potential source correlating to aneurysm rupture.

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.

Morphologic and Hemodynamic Analysis in the Patients with Multiple Intracranial Aneurysms: Ruptured versus Unruptured

Background and Purpose

The authors evaluated the impact of morphologic and hemodynamic factors on multiple intracranial aneurysms and aimed to identify which parameters can be reliable indexes as one aneurysm ruptured, and the others did not.

Methods

Between June 2011 and May 2014, 69 patients harboring multiple intracranial aneurysms (69 ruptured and 86 unruptured) were analyzed from 3D-digital subtraction angiography (DSA) images and computational fluid dynamics (CFD). Morphologic and hemodynamic parameters were evaluated for significance with respect to rupture. Receiver operating characteristic (ROC) analysis identified area under the curve (AUC) and optimal thresholds separating ruptured from unruptured intracranial aneurysms for each parameter. Significant parameters were examined by binary logistic regression analysis to identify independent discriminators.

Results

Nine morphologic (size, neck width, surface area, volume, diameter of parent arteries, aspect ratio, size ratio, lateral/bifurcation type and regular/irregular type) and 6 hemodynamic (WSSmean, WSSmin, OSI, LSA, flow stability and flow complexity) parameters achieved statistical significance (p<0.05). Six morphologic (size, surface area, volume, aspect ratio, size ratio and regular/irregular type) and five hemodynamic (WSSmean, WSSmin, LSA, flow stability and flow complexity) parameters had high AUC values (AUC>0.7). By binary logistic regression analysis, large aspect ratio and low WSSmean were the independently significant rupture factors (AUC, 0.924; 95% CI, 0.883–0.965).

Conclusions

Large aspect ratio and low WSSmean were independently associated with the rupture status of multiple intracranial aneurysms.

Influence of morphology and hemodynamic factors on rupture of multiple intracranial aneurysms: matched-pairs of ruptured-unruptured aneurysms located unilaterally on the anterior circulation

BACKGROUND

The authors evaluated the impact of morphological and hemodynamic factors on the rupture of matched-pairs of ruptured-unruptured intracranial aneurysms on one patient's ipsilateral anterior circulation with 3D reconstruction model and computational fluid dynamic method simulation.

METHODS

20 patients with intracranial aneurysms pairs on the same-side of anterior circulation but with different rupture status were retrospectively collected. Each pair was divided into ruptured-unruptured group. Patient-specific models based on their 3D-DSA images were constructed and analyzed. The relative locations, morphologic and hemodynamic factors of these two groups were compared.

RESULTS

There was no significant difference in the relative bleeding location. The morphological factors analysis found that the ruptured aneurysms more often had irregular shape and had significantly higher maximum height and aspect ratio. The hemodynamic factors analysis found lower minimum wall shear stress (WSSmin) and more low-wall shear stress-area (LSA) in the ruptured aneurysms than that of the unruptured ones. The ruptured aneurysms more often had WSSmin on the dome.

CONCLUSIONS

Intracranial aneurysms pairs with different rupture status on unilateral side of anterior circulation may be a good disease model to investigate possible characteristics linked to rupture independent of patient characteristics. Irregular shape, larger size, higher aspect ratio, lower WSSmin and more LSA may indicate a higher risk for their rupture.

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.

Neurology of pregnancy

Pregnancy creates alterations in maternal physiology which predispose to unique neurologic disorders. Pre-eclampsia, eclampsia, certain types of ischemic and hemorrhagic stroke, reversible cerebral vasoconstriction syndrome, posterior reversible encephalopathy syndrome, and thunderclap headache all appear to share a common origin from vascular endothelial dysfunction, with overlapping clinical presentations. Multiple sclerosis often improves during pregnancy. Compression mononeuropathies may occur in the extremities. Myasthenia gravis may affect second stage labor. Various inflammatory peripheral neuropathies, dystrophies, myopathies may occur during pregnancy. The safety of specific immune suppressants is reviewed. Epilepsy does not have a significant effect upon the course of pregnancy, albeit there is a modest increase in the need for cesarean section. Certain antiepileptic drugs may produce fetal malformations, most notably valproic acid. Brain tumors are rare during pregnancy, but may increase in size due to activation of hormonal receptors on tumor cells surfaces, water retention, and engorged blood vessels.

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.