Hemodynamic and morphological characteristics of unruptured posterior communicating artery aneurysms with oculomotor nerve palsy

The rupture risk factors of mirror intracranial aneurysms: A systematic review and meta-analysis based on morphological and hemodynamic parameters

OBJECTIVE

Intracranial aneurysms (IAs) are a prevalent form of vascular disease that can lead to fatal outcomes upon rupture. Mirror intracranial aneurysms (MIAs) are a specific type of multiple aneurysms situated symmetrically on both sides of the parent arteries. The factors contributing to the risk of MIA rupture, based on morphological and hemodynamic parameters, are currently controversial. Thus, we conducted a systematic review and meta-analysis to investigate the risk factors for MIA rupture.

METHODS

The study performed an electronic search of Chinese and English databases, including China national Knowledge Infrastructure (CNKI), WanFang, VIP, PubMed, Embase, Web of Science, Scopus, and the Cochrane Library databases, and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The morphological parameters (IA size, aspect ratio [AR], size ratio [SR], bottleneck factor [BNF], height-width ratio [HWR], irregular shape) and hemodynamic parameters (wall shear stress [WSS], low WSS area [LSA], oscillatory shear index [OSI]) were analyzed for their significance in determining the risk of MIA rupture.

RESULTS

The analysis comprised 18 retrospective studies involving 647 patients, with a total of 1294 IAs detected, including 605 ruptured and 689 unruptured. The meta-analysis revealed that IA size, AR, SR, and irregular shape exhibited significant differences between the ruptured and unruptured groups, but HWR did not. In terms of hemodynamic parameters, WSS, OSI, and LSA were found to have significant differences between the two groups.

CONCLUSIONS

Our results demonstrate that larger IAs, higher AR, SR, and BNF are associated with a higher risk of rupture in patients with MIAs, regardless of their location. there is no significant difference in HWR between the ruptured and unruptured groups. These preliminary findings offer valuable insights for clinical decision-making and a more comprehensive comprehension of the current MIA status. Nevertheless, larger and multi-center studies are indispensable for corroborating these findings. Systematic review registration: https://www.crd.york.ac.uk/prospero/ identifier: CRD42022345587.

Risks for Oculomotor Nerve Palsy and Time to Recovery After Surgical Clipping of Posterior Communicating Artery Aneurysms: A Multicenter Retrospective Cohort Study

BACKGROUND

Aneurysms of the posterior communicating segment of carotid artery (PcomA) have a high risk of rupture; when these nonruptured aneurysms are associated with oculomotor nerve palsy (ONP), the risk of rupture increases compared with asymptomatic nonruptured PcomA.

OBJECTIVE

To retrospectively analyze the risk factors involved in ONP secondary to PcomA aneurysm and to study the factors involved in the recovery time of ONP once it is established.

METHODS

This was a retrospective study of patients from 10 neurosurgery centers from October 2008 to December 2020. We analyzed age at diagnosis, presence of compressive neuropathy of the oculomotor nerve, presence of aneurysm rupture, largest aneurysm diameter, aneurysm projection, smoking, hypertension, diabetes, time between diagnosis and surgical treatment, as well as the outcome.

RESULTS

Approximately 1 in 5 patients (119/511 23.3%) with a PcomA presented with ONP. We found that patients with aneurysms measuring greater than or equal to 7.5 mm were 1.6 times more likely to have ONP than those with aneurysms smaller than 7.5 mm. In our study, the prevalence of smoking in the PcomA + ONP group was 57.76%, and we also found that smokers were 2.51 times more likely to develop ONP. A total of 80.7% showed some degree of improvement, and 45.4% showed complete improvement with a median recovery time of 90 days.

CONCLUSION

This study showed that 80.7% of patients with PcomA aneurysms undergoing surgical treatment with aneurysm clipping showed some degree of improvement of the ONP, with a median time to recovery between 90 and 120 days.

Nomogram model for predicting oculomotor nerve palsy in patients with intracranial aneurysm

AIM

To explore the risk factors of oculomotor nerve palsy (ONP) in patients with intracranial aneurysm (IA) and develop a nomogram model for predicting ONP of IA patients.

METHODS

A total of 329 IA patients were included. Logistic regression analysis was applied to identify independent factors, which were then integrated into the nomogram model. The performance of the nomogram model was evaluated by calibration curve, receiver operating curve (ROC), and decision curve analysis.

RESULTS

Univariate and multivariate logistic regression analysis indicated posterior communicating artery (PCoA) aneurysm [hazard ratio (HR)=17.13, P<0.001] and aneurysm diameter (HR=1.31, P<0.001) were independent risk factors of ONP in IA patients. Based on the results of logistic regression analysis, a nomogram model for predicting the ONP in IA patients was constructed. The calibration curve indicated the nomogram had a good agreement between the predictions and observations. The nomogram showed a high predictive accuracy and discriminative ability with an area under the curve (AUC) of 0.863. The decision curve analysis showed that the nomogram was powerful in the clinical decision. PCoA aneurysm (HR=3.38, P=0.015) was identified to be the only independent risk factor for ONP severity.

CONCLUSION

PCoA aneurysm and aneurysm diameter are independent risk factors of ONP in IA patients. The nomogram established is performed reliably and accurately for predicting ONP. PCoA aneurysm is the only independent risk factor for ONP severity.

Efficacy and long-term results of endovascular embolization and surgical clipping for posterior communicating artery unruptured aneurysms complicated with oculomotor nerve palsy

to investigate the efficacy and long-term outcomes of endovascular embolization and surgical clipping for patients with posterior communicating artery unruptured aneurysms (PcomAs) concomitant with oculomotor nerve palsy (ONP). No significant (P > .05) difference existed in the age, gender, proportion of complete ONP, and size of eye fissure and pupil before treatment between 2 groups. After compared with before treatment, the eye fissure was widened significantly (P < .05) and the pupil narrowed significantly (P < .05), but no significant (P > .05) differences existed between the 2 groups. Complete ONP recovery was observed in 32 (80%) patients in the embolization group and 31 (77.5%) in the microsurgical group, partial ONP recovery occurred in 6 (15%) in the embolization group and 8 (20%) in the microsurgical group. The recovery rate was 95% in the embolization group and 97.5% in the microsurgical group, with no significant (P > .05) difference between 2 groups. The recovery rate of the ONP was significantly (P < .01) greater in the microsurgical group than that in the embolization group at follow-up of 1 month, 3 months, six and 12 months, respectively. At 18 months, the ONP recovery rate was not significantly different between 2 groups (95% vs 97.5%) Surgical clipping may have a faster effect on the recovery of oculomotor nerve palsy than endovascular embolization for patients with posterior communicating artery unruptured aneurysms complicated with oculomotor nerve palsy, but both approaches may result in a similar effect on the nerve recovery in the long run.Eighty patients treated with endovascular embolization or surgical clipping were retrospectively enrolled into the endovascular embolization group or surgical clipping and analyzed.

Radiologic assessment of rupture risk in small (<5 mm) posterior communicating artery aneurysms

Although previous studies have investigated the predictors of posterior communicating artery (PCoA) aneurysm rupture with clinical and radiologic parameters, the accessibility of "small PCoA aneurysms (<5 mm)" has rarely been reported. Here, we designed a study to identify the factors which are thought to be risky and prone to rupture in small PCoA aneurysms (<5 mm).A total of 114 patients diagnosed with PCoA aneurysm under 5 mm in size on digital subtraction angiography were retrospectively enrolled and divided into ruptured (n = 51) and unruptured (n = 63) groups. Clinical variables were reviewed, and 10 radiologic parameters were obtained, including maximum diameter, height, width, neck width, aspect ratio, dome-to-neck ratio, bleb formation, size ratio, presence of fetal-type PCoA, and inflow angle. Statistical analyses were conducted to compare the groups (ruptured vs unruptured) and identify the risk factors for rupture.High rupture rate of small PCoA aneurysm is noted (51/114, 44.7%). In the comparison analysis, parameters of size ratio (P = .045), aspect ratio (P = .001), and bleb formation (P = .015) were significantly different between the 2 groups. In the regression model, the aspect ratio (P = .045) and bleb formation (P = .004) were significantly associated with the rupture of aneurysm.In respect of small (<5 mm) PCoA aneurysms of our cohort, morphologic parameters of "bleb formation" and "a high aspect ratio" are present more often in ruptured aneurysms as compared to unruptured aneurysms.

U-Shaped Association of Aspect Ratio and Single Intracranial Aneurysm Rupture in Chinese Patients: A Cross-Sectional Study

Background: Previous studies have analyzed the association of aspect ratio (AR) on the ruptured intracranial aneurysm (IA), but the findings are inconclusive and controversial. Therefore, the study aimed to derive a more detailed estimation of this association between AR and ruptured IA in Chinese IA patients. Methods: The present work was a cross-sectional study. We retrospectively collected 1,588 Chinese patients with a single IA from January 2010 to November 2017. The relationship was examined between AR at diagnosis and ruptured IA. Covariates included data of demographics, morphological parameters, lifestyle habits, clinical features, and comorbidities. Binary logistic regression and two-piecewise linear models were used to analyze independent associations of AR with ruptured IA. Results: The results suggest that the association between AR and IA rupture was U-shaped. In the AR range of 1.08-1.99, the prevalence of IA rupture was 13% lower for each 0.1-unit increment in AR [odds ratio 0.87, 95% confidence interval (CI) 0.80-0.98]. Conversely, for every 0.1-unit increase in AR, the prevalence of IA rupture increased by ~3% (odds ratio 1.03, 95% CI 1.01-1.06) in the AR range of 3.42-4.08. Conclusion: The relationship between AR and ruptured IA was U-shaped, with the negative association at AR of 1.08-1.99 and positive association at AR of 3.42-4.08.

Hemodynamic and Morphological Parameters of Ruptured Mirror Posterior Communicating Artery Aneurysms

Objective: Morphological and hemodynamic parameters might predict rupture of intracranial aneurysms (IAs). A practical model for the study is patients with ruptured mirror IAs in which one is ruptured and the other is unruptured. Although there have been analyses of the morphology and hemodynamics of ruptured mirror posterior communicating artery aneurysms (PComAAs), the sample sizes in these studies were small and only considered hemodynamics or morphological characters. Therefore, this study aimed to investigate the morphological and hemodynamic parameters associated with ruptured mirror PComAAs. Methods: We considered 72 patients with ruptured mirror PComAAs using computational fluid dynamics (CFDs). Ruptured mirror PComAAs were divided into ruptured and unruptured groups. Fourteen morphological and eight hemodynamic parameters were calculated and compared. Significant parameters were analyzed by the multivariate logistic regression to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for all independent risk factors to determine the predictability and identify the optimal threshold. Results: Four hemodynamic and three morphological parameters were significantly different between ruptured and unruptured groups: normalized wall shear stress (NWSS), mean WSS, low wall shear WSS area (LSA%), size, aspect ratio (AR), size ratio (SR), and inflow angle (IA). Multivariate logistic regression analysis showed that AR, SR, NWSS, mean WSS, and LSA% were all independent factors significantly associated with PComAAs rupture. The ROC analysis for independent risk factors indicated that AR (0.751), NWSS (0.755), mean WSS (0.69), and LSA (0.778) had merely acceptable AUC values. Only SR (0.803) had a high acceptable AUC value. The threshold value of SR was 1.96. Conclusions: SR (>1.96) was the most significant parameter associated with IA rupture, whereas AR, NWSS, mean WSS, and LSA independently characterized the status of IA rupture.

Prediction of rupture risk in cerebral aneurysms by comparing clinical cases with fluid-structure interaction analyses

Cerebral aneurysms should be treated on the basis of accurate rupture risk prediction. Nowadays, the rupture risk in aneurysms has been estimated using hemodynamic parameters. In this paper, we suggest a new way to predict the rupture risks in cerebral aneurysms by using fluid–structure interaction (FSI) analysis for better decision-making regarding treatment. A patient-specific model was constructed using digital subtraction angiography of 51 cerebral aneurysms. For each model, a thin-walled area (TWA) was first predicted using computational fluid dynamics (CFD), and then the highest equivalent strain in the TWA was calculated with FSI by varying wall thicknesses and mechanical properties. A critical curve was made from 16 FSI results for each patient-specific model to estimate the rupture risk. On average, the equivalent strains of the ruptured aneurysms were higher than those of the unruptured aneurysms. Furthermore, the patterns of critical curves between unruptured and ruptured aneurysms were clearly distinguishable. From the rupture risk evaluation based on the cut-off value, 24 of the 27 unruptured aneurysms and 15 of the 24 ruptured aneurysms were matched with actual-clinical setting cases. The critical curve proposed in the present study could be an effective tool for the prediction of the rupture risk of aneurysm.

Hemodynamic and Morphological Differences Between Unruptured Carotid-Posterior Communicating Artery Bifurcation Aneurysms and Infundibular Dilations of the Posterior Communicating Artery

Objective: Posterior communicating artery bifurcation aneurysms (PcomA-BAs) and infundibular dilations (PcomA-IDs) are found at the junction between the internal carotid artery (ICA) and the posterior communicating artery (PcomA). Several studies found that PcomA-IDs potentially progress to aneurysms and can even rupture. In our clinical practice, digital subtraction angiography (DSA) helps differentiate PcomA-IDs from unruptured PcomA-BAs. However, when PcomA-IDs are >3 mm in diameter or PcomA are absent on DSA, it is challenging to use DSA to differentiate PcomA-IDs from unruptured PcomA-BAs. Hemodynamic and morphological factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. We compared hemodynamic and morphological differences in unruptured PcomA-BAs and PcomA-IDs to better manage PcomA-IDs. Methods: We included 83 PcomA-IDs and 115 unruptured PcomA-BAs dignosed and measured using DSA from January 2015 to January 2019. Computational fluid dynamics was performed on these patient-specific models reconstructed using axial slices in DICOM format. Clinical, hemodynamic, and morphological factors were compared between the PcomA-IDs and PcomA-BAs. Significant parameters were analyzed using binary logistic regression analysis to identify independent risk factors. Receiver operating characteristic (ROC) analysis was performed on the independent risk factors to acquire cutoff values. Results: One hemodynamic and four morphyological parameters were significantly different between PcomA-IDs and PcomA-BAs: normalized wall shear stress (NWSS), size, the angle between the ophthalmic segment of the ICA and the PcomA (APcomA), the angle between the ophthalmic and the communicating segment of the ICA (AICA) and the diameter of the PcomA (DPcomA). Binary logistic regression analysis showed that small size and DPcomA as well as APcomA were all independent significant factors characterizing the status of PcomA-IDs and the ROC analysis for independent risk factors indicated the cutoff values of size, APcomA, and DPcomA were 3.45 mm, 66.27°, and 1.24 mm, respectively. Conclusions: Size, DpcomA, and ApcomA could independently characterize the status of PcomA-IDs. These might help us better differentiate them from real aneurysms and guide its management.

Endovascular versus surgical treatment for improvement of oculomotor nerve palsy caused by unruptured posterior communicating artery aneurysms

Background

There is no consensus regarding the best treatment option for unruptured aneurysms of the posterior communicating artery (PCom) presenting with oculomotor nerve palsy (ONP). We aimed to assess predictors of ONP recovery in a multicenter series of consecutive patients.

Materials and methods

A retrospective review of prospective databases in three tertiary neurosurgical centers was carried out, selecting patients with ONP caused by unruptured PCom aneurysms, treated by surgical clipping or embolization, between January 2006 and December 2013. Patient files and imaging studies were used to extract ophthalmological assessments, treatment outcomes, and follow-up data. Predictors of ONP recovery during follow-up were explored using univariate and multivariate analyses.

Results

We identified 55 patients with a median ONP duration before treatment of 11 days (IQR 4.5–18); the deficit was complete in 27 (49.1%) and incomplete in 28 (50.9%) cases. Median aneurysm size was 7 mm (IQR 5–9). Twenty-four (43.6%) patients underwent surgical clipping and 31 (56.4%) embolization as the primary treatment. Overall, ONP improved in 40 (72.7%) patients and persisted/recurred in 15 (27.3 %). Surgery, interval to complete treatment <4 weeks, aneurysm recurrence during follow-up, and retreatment during follow-up were significantly correlated with ONP outcome in the univariate analysis. In the multivariate analysis, independent predictors of ONP improvement were interval to complete treatment <4 weeks (OR 5.15, 95% CI 1.37 to 23.71, p=0.015) and aneurysm recurrence during follow-up (OR 0.1, 95% CI 0.02 to 0.47, p=0.003).

Conclusion

There was no significant difference in ONP recovery between surgical clipping and embolization. The best predictor for ONP recovery was timely, complete, and durable aneurysm exclusion.

Wall Enhancement, Hemodynamics, and Morphology in Unruptured Intracranial Aneurysms with High Rupture Risk

The purpose of this study is to investigate the relationship between morphology, hemodynamics, and aneurysm wall enhancement (AWE) on vessel wall MRI and their potential role in rupture of intracranial aneurysms. Fifty-seven patients (22 males and 35 females; mean age of 58.4) harboring 65 unruptured intracranial aneurysms were retrospectively recruited. Vessel wall MRI images were reviewed and differentiated as no (NAWE), partial (PAWE), and circumferential (CAWE) wall enhancement. Computational geometry and computational fluid dynamics were used to calculate morphological and hemodynamic parameters. The PHASES score was calculated for each case to estimate its rupture risk. Univariate and multivariate logistic regression analysis was performed to investigate the relationship between morphological-hemodynamic pattern and AWE as well as their association with rupture risk. AWE was present in 26 (40.0%) lesions, including 14 (21.5%) PAWE and 12 (18.5%) CAWE. Aneurysm size (odds ratio = 7.46, 95% confidence interval = 1.56–35.77, p = 0.012), size ratio (odds ratio = 12.90, 95% confidence interval = 2.28–72.97, p = 0.004), and normalized wall shear stress (odds ratio = 0.11, 95% confidence interval = 0.02–0.69, p = 0.018) were independently associated with the presence of AWE. With increasing PHASES score, size-related parameters and the frequency of irregular shape increased significantly, and a hemodynamic pattern of lower and oscillating wall shear stress was observed. Simultaneously, the proportion of NAWE aneurysms decreased, and PAWE and CAWE aneurysms increased significantly (p < 0.001). Unruptured intracranial aneurysms with a higher rupture risk presented with a significantly larger size, lower wall shear stress, and more intense AWE, which might support the interaction between morphology, hemodynamics, and inflammation and their potential role in aneurysm rupture prediction.

Hemodynamic and Morphological Analysis of Mirror Aneurysms Prior to Rupture

OBJECTIVE

Hemodynamic factors are thought to play important roles in the pathogenesis, progression, and rupture of cerebral aneurysms. Previous hemodynamic studies have been based on comparisons between post-ruptured and unruptured aneurysms. Nevertheless, changes of aneurysm morphology after rupture render these results unreliable. Moreover, pressure, age, gender, and the morphology of the parent artery also influence these results. Therefore, in the present study, we identified hemodynamic and morphological characteristics of aneurysms prior to rupture using twelve mirror aneurysms.

MATERIALS AND METHODS

From our database, we retrospectively analyzed twelve mirror aneurysms (MANs) prior to rupture. Each mirror aneurysm was divided into the prior to rupture or the unruptured group. Patient-specific models were reconstructed from three-dimensional (3D) images of all patients. Hemodynamic and morphological factors were analyzed and compared.

RESULTS

Compared with the unruptured side of MANs, aneurysms prior to rupture were significantly larger and significantly more irregular in shape; they also had significantly higher aspect ratio (AR), size ratio (SR), undulation index (UI), ellipticity index (EI), percentage of low wall shear stress area (LSA) and significantly lower normal wall shear stress (NWSS). The oscillatory shear index (OSI) and nonsphericity index (NSI) in the aneurysms prior to rupture were non-significantly higher than those of the unruptured group.

CONCLUSION

MANs prior to rupture may be extremely useful models to assess the risk of aneurysm rupture. Larger size, irregular shape, higher AR, SR, UI, NI, and lower WSS may be associated with aneurysms at risk for rupture.

Detection of microbleeds associated with sentinel headache using MRI quantitative susceptibility mapping: pilot study

OBJECT

Sentinel headaches (SHs) associated with cerebral aneurysms (CAs) could be due to microbleeds, which are considered a sign that an aneurysm is unstable. Despite the prognostic importance of these microbleeds, they remain difficult to detect using routine imaging studies. The objective of this pilot study is to detect microbleeds associated with SH using a magnetic resonance imaging (MRI) quantitative susceptibility mapping (QSM) sequence and then evaluate the morphological characteristics of unstable aneurysms with microbleeds.

METHODS

Twenty CAs in 16 consecutive patients with an initial presentation of headache (HA) leading to a diagnosis of CA were analyzed. Headaches in 4 of the patients (two of whom had 2 aneurysms each) met the typical definition of SH, and the other 12 patients (two of whom also had 2 aneurysms each) all had migraine HA. All patients underwent imaging with the MRI-QSM sequence. Two independent MRI experts who were blinded to the patients' clinical history performed 3D graphical analysis to evaluate for potential microbleeds associated with these CAs. Computational flow and morphometric analyses were also performed to estimate wall shear and morphological variables.

RESULTS

In the 4 patients with SH, MRI-QSM results were positive for 4 aneurysms, and hence these aneurysms were considered positive for non-heme ferric iron (microbleeds). The other 16 aneurysms were negative. Among aneurysm shape indices, the undulation index was significantly higher in the QSM-positive group than in the QSM-negative group. In addition, the spatial averaged wall shear magnitude was lower in the aneurysm wall in direct contact with microbleeds.

CONCLUSIONS

MRI-QSM allows for objective detection of microbleeds associated with SH and therefore identification of unstable CAs. CAs with slightly greater undulation indices are associated with positive MRI-QSM results and hence with microbleeds. Studies with larger populations are needed to confirm these preliminary findings.

Identification of Hostile Hemodynamics and Geometries of Cerebral Aneurysms: A Case-Control Study

BACKGROUND AND PURPOSE

Hostile hemodynamic conditions and geometries are thought to predispose aneurysms for instability and rupture. This study compares stable, unstable, and ruptured aneurysms while controlling for location and patient characteristics.

MATERIALS AND METHODS

The hemodynamics and geometries of 165 stable, 65 unstable, and 554 ruptured aneurysms were compared. Hemodynamics was modeled using image-based computational fluid dynamics. Case-control pairs were selected matching aneurysm location, patient age, and sex. Paired Wilcoxon tests were used to compare hemodynamic and geometric variables among different aneurysm groups. The pairing was repeated 100 times, and the combined P values were calculated and adjusted for multiple testing.

RESULTS

Ruptured aneurysms had lower minimum wall shear stress (P = .03), higher maximum wall shear stress (P = .03), more concentrated (P = .03) and mean oscillatory shear stress (P = .03), higher maximum velocity (P = .03), and more complex flows (vortex core-line length, P = .03) than stable aneurysms. Similarly, unstable aneurysms had more concentrated shear stress (P = .04) and more complex flows (vortex core-line length, P = .04) than stable aneurysms. Compared with stable aneurysms, ruptured aneurysms were larger (size ratio, aneurysm size/vessel size, P = .03), more elongated (aspect ratio, P = .03), and irregular (nonsphericity index, P = .03). Similarly, unstable aneurysms were larger (size ratio, P = .04), more elongated (aspect ratio, P = .04), and irregular (bulge location, P = .04; area-weighted Gaussian curvature; P = .04) than stable aneurysms. No significant differences were found between unstable and ruptured aneurysms.

CONCLUSIONS

Unstable and ruptured aneurysms have more complex flows with concentrated wall shear stress and are larger, more elongated, and irregular than stable aneurysms, independent of aneurysm location and patient sex and age.

Morphological and Hemodynamic Parameters for Middle Cerebral Artery Bifurcation Aneurysm Rupture Risk Assessment

OBJECTIVE

To investigate the morphological and hemodynamic parameters associated with middle cerebral artery (MCA)bifurcation aneurysm rupture.

METHODS

A retrospective study of 67 consecutive patients was carried out based on 3D digital subtraction angiography data. Morphological and hemodynamic parameters including aneurysm size parameters (dome width, height, and perpendicular height), longest dimension from the aneurysm neck to the dome tip, neck width, aneurysm area, aspect ratio, Longest dimension from the aneurysm neck to the dome tip (Dmax) to dome width, and height-width, Bottleneck factor, as well as wall shear stress (WSS), low WSS area (LSA), percentage of LSA (LSA%) and energy loss (EL) were estimated. Parameters between ruptured and un-ruptured groups were analyzed. Receiver operating characteristics were generated to check prediction performance of all significant variables.

RESULTS

Sixty-seven patients with MCA bifurcation aneurysm were included (31 unruptured, 36 ruptured). Dmax (p=0.008) was greater in ruptured group than that in un-ruptured group. D/W (p<0.001) and the percentage of the low WSS area (0.09±0.13 vs. 0.01±0.03, p<0.001) were also greater in the ruptured group. Moreover, the EL in ruptured group was higher than that in un-ruptured group (6.39±5.04 vs. 1.53±0.86, p<0.001). Multivariate regression analysis suggested D/W and EL were significant predictors of rupture of MCA bifurcation aneurysms. Correlation analyses revealed the D/W value was positively associated with the EL (R=0.442, p<0.01).

CONCLUSION

D/W and EL might be the most two favorable factors to predict rupture risk of MCA bifurcation aneurysms.

Association of wall shear stress with intracranial aneurysm rupture: systematic review and meta-analysis

To evaluate the relationship between wall shear stress (WSS) magnitude and cerebral aneurysm rupture and provide new insight into the disparate computational fluid dynamics (CFD) findings concerning the role of WSS in intracranial aneurysm (IA) rupture. A systematic electronic database (PubMed, Medline, Springer, and EBSCO) search was conducted for all accessible published articles up to July 1, 2016, with no restriction on the publication year. Abstracts, full-text manuscripts, and the reference lists of retrieved articles were analyzed. Random effects meta-analysis was used to pool the complication rates across studies. Twenty-two studies containing CFD data on 1257 patients with aneurysms were included in the analysis. A significantly higher rate of low WSS (0–1.5 Pa) was found in ruptured aneurysms (odds ratio [OR] 2.17; 95% confidence interval [CI], 1.73–2.62). The pooled analyses across 14 studies with low WSS showed significantly lower mean WSS (0.64 vs. 1.4 Pa) (p = 0.037) in the ruptured group. This meta-analysis provides evidence that decreased local WSS may be an important predictive parameter of IA rupture.