Aneurysm Dome Research Articles

REMOVED: Enlarged Anterior Cerebral Artery Bifurcation Angles May Induce Abnormally Enhanced Hemodynamic Stresses to Initiate Aneurysms

To investigate the relationship of anterior cerebral artery (ACA) bifurcation angles with hemodynamic stresses for aneurysm initiation. Forty patients with or without anterior communicating artery aneurysms were enrolled, and 3 patients with ACA bifurcation angles of 169.0°, 136.9°, and 73.2°, respectively, were entered into computational fluid dynamics analysis for hemodynamic stresses. Larger bifurcation angles had a larger direct flow impinging zone and larger peak pressure area. In the direct flow impinging center, the total pressure was the highest, whereas the other stresses were the lowest. As blood flowed distally, the total pressure decreased rapidly, whereas all other parameters increased quickly to their peaks. The hemodynamic peak distance was decreased as the bifurcation angle became narrower. The total pressure summit and the peak hemodynamic stresses all decreased with the decrease of bifurcation angles. The distance between the hemodynamic peaks was the smallest at 73.2° compared with larger angles. A significant (P < 0.01) positive linear correlation existed in the ACA bifurcation angle with the distance between hemodynamic stress peaks or in the ACA branch diameter with the distance from the direct impinging center to the ipsilateral hemodynamic stress peak. The hemodynamic stresses on the aneurysm dome were significantly (P < 0.001) smaller than at the aneurysm initiation site. Larger bifurcation angles may lead to abnormally enhanced hemodynamic stresses, enlarged zones of direct flow impingement, and increased distance between hemodynamic stress peaks to damage the vascular wall for aneurysm initiation on the bifurcation apex wall.

Microsurgical Treatment of Unruptured Anterior Choroidal Artery Aneurysms: Incidence of and Risk Factors for Procedure-Related Complications

To describe our experiences with microsurgical treatment of unruptured anterior choroidal artery (AchA) aneurysms, and to evaluate the incidence of and risk factors for procedure-related complications. The study included 110 patients treated between January 2012 and December 2016. All patients met the following criteria: 1) microsurgical treatment of an unruptured AchA aneurysm was performed; and 2) clinical and radiographic follow-up data were available, including findings from preoperative digital subtraction angiography. The incidence of and risk factors for procedure-related complications were retrospectively evaluated. The χ2 test and Mann-Whitney U test were used in statistical analysis, and univariate analysis and multivariate logistic regression analysis were conducted. Procedure-related complications occurred in 5 patients (4.5%), including symptomatic complications in 4 patients (3.6%) and asymptomatic complications in 1 patient (0.9%). Multivariate logistic regression analysis indicated that the angle between the vertical line to the cranial base and the axis of the communicating segment of the internal carotid artery (MiC angle) (odds ratio [OR], 1.66; 95% confidence interval [CI], 1.13-5.26; P= 0.038) and the angle between the projection line of the aneurysmal dome and the axis of the communicating segment of the internal carotid artery (DC angle) (OR, 3.82; 95% CI, 1.49-11.7; P= 0.014) were independent risk factors for procedure-related complications. When microsurgical treatment of unruptured AchA aneurysms was performed, the procedure-related complication rate was 4.5%. Patients with AchA aneurysms with a smaller MiC angle and smaller DC angle may be at a higher risk of procedure-related complications when undergoing microsurgical treatment.

Correlating Clinical Risk Factors and Histological Features in Ruptured and Unruptured Human Intracranial Aneurysms: The Swiss AneuX Study

Pathogenesis of intracranial aneurysm is complex and the precise biomechanical processes leading to their rupture are uncertain. The goal of our study was to characterize the aneurysmal wall histologically and to correlate histological characteristics with clinical and radiological factors used to estimate the risk of rupture. A new biobank of aneurysm domes resected at the Geneva University Hospitals (Switzerland) was used. Histological analysis revealed that unruptured aneurysms have a higher smooth muscle cell (SMC) content and a lower macrophage content than ruptured domes. These differences were associated with more collagen in unruptured samples, whereas the elastin content was not affected. Collagen content and type distribution were different between thick and thin walls of unruptured aneurysms. Classification of aneurysm domes based on histological characteristics showed that unruptured samples present organized wall rich in endothelial and SMCs compared with ruptured samples. Finally, aneurysm wall composition was altered in unruptured domes of patients presenting specific clinical factors used to predict rupture such as large dome diameter, dome irregularities, and smoking. Our study shows that the wall of aneurysm suspected to be at risk for rupture undergoes structural alterations relatively well associated with clinical and radiological factors currently used to predict this risk.

Risk Factors for Intracranial Aneurysm Rupture: A Systematic Review.

Intracranial aneurysm rupture prediction is poor, with only a few risk factors for rupture identified and used in clinical practice. To provide an overview of all the risk factors (including genetic, molecular, morphological, and hemodynamic factors) that have potential for use in clinical practice. We systematically searched PubMed and EMBASE and focused on factors that can be easily assessed in clinical practice, might be used for rupture prediction in clinical practice, and/or are potential targets for further research. Studies were categorized according to methodological quality, and a meta-analysis was performed, if possible. We included 102 studies describing 144 risk factors that fulfilled predefined criteria. There was strong evidence for the morphological factors irregular shape (studied in 4 prospective cohort studies of high-quality, pooled odds ratio [OR] of 4.8 [95% confidence interval 2.7-8.7]), aspect ratio (pooled OR 10.2 [4.3-24.6]), size ratio, bottleneck factor, and height-to-width ratio to increase rupture risk. Moderate level of evidence was found for presence of contact with the perianeurysmal environment (pooled OR 3.5 [1.4-8.4]), unbalanced nature of this contact (pooled OR 17.8 [8.3-38.5]), volume-to-ostium ratio, and direction of the aneurysm dome (pooled OR 1.5 [1.2-1.9]). Irregular aneurysm shape was identified as a risk factor with potential for use in clinical practice. The risk factors aspect ratio, size ratio, bottleneck factor, height-to-width ratio, contact with the perianeurysmal environment, volume-to-ostium ratio, and dome-direction should first be confirmed in multivariate analysis and incorporated in prediction models.

Long-term follow-up in the endovascular treatment of intracranial aneurysms with flow-diverter stents: update of a single-centre experience.

Flow-diverter stents are becoming a useful tool in treating patients with intracranial aneurysms with suitable anatomical feature. Purpose of this study was to evaluate effectiveness and safety of endovascular treatment with flow-diverting stents (FD) in unruptured intracranial aneurysms. From May 2009 and May 2014, we treated 49 patients with a total of 58 aneurysms, with FD technique. All patients were treated electively, under general anesthesia and were administered single antiplatelet drug 5days before the procedure and double antiplatelet therapy for 3months afterwards. Fifteen of the patients were asymptomatic, eight had headache, thirteen patients presented symptoms due to mass effect of the aneurysm on CNS structures, twelve were treated due to a post-surgical relapse and one patient presented relapsing TIAs due to distal embolization from the aneurysm dome. Choice of FD treatment was done according to aneurysm anatomy (fusiform over saccular, dome/neck ratio<2) and whenever conventional treatment (coil embolization) appeared difficult (eg. Large aneurysm neck, fusiform aneurysms or difficult sac catheterization). We considered a dome/neck ratio>2 as the only exclusion criteria. Successful stent deployment was achieved in 50 procedures out of 52 (94.34%) while overall mortality was 2% (1/49). Forty-eight patients were evaluated at long-term follow-up for a total of 56 treated aneurysms. At 3months, follow-up 75% (42/56) of the aneurysms were excluded from intracranial circulation, at 6months 80.35% (45/56) and at 12months 84% (47/56). Stent patency was observed in 100% of patients at short and long-term follow-up, with only two cases of intimal hyperplasia at 3months, without any further complications. According to our study FD repair of unruptured intracranial aneurysms appeared to be a safe and effective technique, especially in selected patients with hostile anatomy for traditional embolization.

Critical role of angiographic acquisition modality and reconstruction on morphometric and haemodynamic analysis of intracranial aneurysms

BackgroundSubtracted 3-D rotational angiography (3DRA) and cone-beam computed tomography angiography (CBCT-A) are often used in assessing cerebral aneurysm shape and haemodynamic profile. We sought to evaluate the effect of imaging...

Presence of Anterior Communicating Artery Aneurysm Is Associated With Age, Bifurcation Angle, and Vessel Diameter.

The anterior communicating artery (Acom) aneurysm is the most complex in all cerebral aneurysms, and wider vascular bifurcation angles are considered to be associated with aneurysm formation. The objective of this study was to investigate association of the Acom aneurysm formation with patient age and vascular bifurcation morphology. Three-dimensional angiographic data of 665 patients were used in this study, including 160 patients with Acom aneurysms, 66 with non-Acom aneurysms, and 439 control subjects with no aneurysms. The anterior cerebral artery bifurcation angle (Acom/A2 angle), arterial diameters, and Acom aneurysm geometric characters were examined. Women of 50 to 70 years were more vulnerable to Acom aneurysm formation than men. The Acom/A2 bifurcation angle was significantly increased (P<0.0001) with increase of patient age. The size of the Acom aneurysm dome and neck was statistically positively correlated with the diameter of the Acom, A1 and A2 segments (P<0.0001). The Acom/A2 bifurcation angle was significantly (P<0.0001) wider in patients with than without Acom aneurysms, whereas the A1/A2 angle was significantly smaller in patients with than without Acom aneurysms (P<0.0001). The Acom aneurysms at the bifurcation apex mostly deviated toward the smaller angle formed between the parent A1 and branches and toward the daughter artery with a smaller diameter. The Acom aneurysms were located mostly on the dominant anterior cerebral artery. The presence of Acom aneurysm is significantly associated with patient age, wider angles of the anterior cerebral artery bifurcation, and smaller vascular diameter of the anterior communicating complex.

Microsurgical clipping of a large ruptured anterior communicating artery aneurysm.

Background:Anterior communicating artery (AComA) aneurysms are the most complex aneurysms of the anterior cerebral circulation. They mostly arise between the dominant A1 and the AComA, and are associated with intraventricular hemorrhage or other aneurysms in around 20%–30% of the cases. Giant and fusiform aneurysms are rare in this location in contrast to the common small ruptured aneurysms. Throughout the treatment, branches of A1–A2 complex such as the orbitofrontal artery, the frontopolar artery, the recurrent artery of Heubner, medial lenticulostriate arteries, and small perforators from the A1–A2 junction should be preserved. The orientation of the aneurysm, undefined in case of tortuous A1, but usually to the contralateral side of the dominant A1, might be downward, forward, upward, backward, or even of a complex morphology. Moreover, the evaluation of the chiasm and skull base, the site of possible rupture, the presence of intraluminal thrombosis, vascular calcifications, or anatomic variations of A1 and A2 segments is required. Since the angle between the AComA perforators and the A2s varies between 30° and 180°, parallel application of the clip along the AComA is unrecommended.Technique:The patient with large ruptured AComA aneurysm underwent supine position. The head, placed above the cardiac level, was minimal extended, and slightly tilted and rotated to the opposite side according to the projection of the aneurysm dome. A left lateral supraorbital approach was performed. The carotid cistern and the lamina terminalis were opened to release cerebrospinal fluid. Arachnoid bands extending from the olfactory triangle to the lateral side of the optic nerve were carefully dissected to find the ipsilateral A1 and the aneurysm. Skillful dissection of the AComA complex under repeated temporary and pilot clips allowed a safe definitive clipping. Occasionally, aneurysm remodeling and shrinking under bipolar coagulation might be required. Intraoperative angiography and/or Doppler ultrasound determine complete occlusion of the aneurysm and patency of the vessels.Conclusion:Skillful microneurosurgery is required for the management of challenging ruptured AComA aneurysms.Videolink:http://surgicalneurologyint.com/videogallery/ruptured-acoma-aneurysm-14

One-stage Stent-assisted Coil Embolization for Rupture-side-unknown Bilateral Vertebral Artery Dissecting Aneurysms in an Acute Stage: A Case Report

Bilateral vertebral artery dissecting aneurysms (VADAs) with subarachnoid hemorrhage (SAH) are rare and their management is still challenging. In this report, we successfully performed one-stage stent-assisted coil embolization (SAC) for bilateral VADAs with SAH in an acute stage, because the ruptured side could not be diagnosed. A 47-year-old woman presented with a sudden onset of headache without laterality, and left-side dominant SAH with bilateral VADAs was noted on computed tomography (CT) scans. The size of aneurysmal dome and neck was similar between the two VADAs, and a bleb was observed only on the right VADA. In computational fluid dynamics (CFD) simulations, findings of wall shear stress (WSS), normalized WSS, and WSS gradient suggested that the left VADA was ruptured, while the oscillatory shear index and aneurysm formation indicator suggested the opposite-side one to be ruptured. Thus, we could not determine which VADA was ruptured by clinical data and CFD analyses. Therefore, we performed simultaneous treatment for the bilateral VADAs by using SAC technique 8 h after the onset under dual antiplatelet and anticoagulation therapies. There was no evidence of rebleeding and stent thrombosis. Stent thrombosis was monitored by duplex color-coded ultrasonography after the intervention. She was discharged without neurological deficits, and 6-month follow-up cerebral angiography demonstrated no recanalization of VADAs. This is the first report showing bilateral VADAs with SAH treated by one-stage SAC within 24 h of SAH, and the potential risks are discussed.

The Microsurgical Relationships between Internal Carotid-Posterior Communicating Artery Aneurysms and the Skull Base.

Objective This study aimed to review the anatomical and clinical characteristics of internal carotid-posterior communicating artery (IC-PC) aneurysms, especially those located close to the skull base. Methods The microsurgical anatomy around the posterior communicating artery (PComA) was examined in a dry skull and five formalin-fixed human cadaveric heads. The clinical characteristics of 37 patients with 39 IC-PC aneurysms, who were treated microsurgically between April 2008 and July 2016, were retrospectively reviewed. Results The anterior clinoid process (ACP), as well as the anterior petroclinoidal dural fold (APF), which forms part of the oculomotor triangle, are closely related to the origin of the PComA. Among the 39 IC-PC aneurysms, anterior clinoidectomy was performed on 4 (10.3%) and a partial resection of the APF was performed on 2 (5.1%). Both of these aneurysms projected inferior to the tentorium, or at least part of the aneurysm's dome was inferior to the tentorium. Conclusion Proximally located IC-PC aneurysms have an especially close relationship with the ACP and APF. We should be familiar with the anatomical relationship between IC-PC aneurysms and the structures of the skull base to avoid hazardous complications.

Assessment of endothelialization of aneurysm wall over time in a rabbit model through CD31 scoring

BackgroundIntracranial aneurysms represent a significant health concern and are poorly understood despite decades of research. Our study focused on understanding temporal patterns of endothelial cell distribution in different spatial locations...

Hemodynamics and coil distribution with changing coil stiffness and length in intracranial aneurysms

PurposeThe purpose of this study was to investigate hemodynamics and coil distribution with changing coil stiffness and length using the finite element method (FEM) and computational fluid dynamics (CFD) analysis.MethodsBasic...

Synchrotron speckle-based x-ray phase-contrast imaging for mapping intra-aneurysmal blood flow without contrast agent

Intracranial aneurysms carry risk of rupture with life threatening consequences. Hemodynamic forces are considered to be the key in cerebral aneurysm rupture. Notably, the hemodynamic analysis requires precise characterization of intra-aneurysmal blood velocity field, raising the need to develop novel measurement techniques. This study aims to assess the performance of speckle-based x-ray phase contrast particle imaging velocimetry (PIV) for velocity field mapping of a pulsatile blood flow in a patient specific aneurysm model without contrast agent. Porcine blood was used in a blood circulation loop including the aneurysm model, which was imaged using the synchrotron x-ray phase contrast imaging (PCI) at an optimum phase propagation distance. X-ray images were processed to improve speckle characteristics for PIV analysis. A computational fluid dynamic (CFD) model was developed for simulation of the blood velocity field and compared to the x-ray PCI-PIV measurements. The CFD model and x-ray PCI-PIV measurements showed similar intra-aneurysmal blood flow structures although the velocity magnitudes were generally higher in CFD model. Contrary to CFD model, x-ray PCI-PIV measurements revealed formation of blood cell stagnation at the aneurysm dome at low blood flow rate, cushioning upon the blood flow shear force. Synchrotron x-ray PCI-PIV offers potential for hemodynamic analysis in patient specific cerebral aneurysm models without contrast agent.

Ruptured Middle Cerebral Artery Aneurysms: Retrospective Study and Multivariate Analysis of 105 Patients Treated by Surgical Clipping

In this retrospective study, we analyzed 105 cases of ruptured MCAAs, admitted from January 2001 to December 2015 at Neurosurgical Department of Umberto I University Hospital of Rome, Italy. Predictive factors evaluated are: patient’s features (age, sex, co-morbidities), aneurysmal location (proximal, bifurcation or distal) and size of aneurysmal dome (small, large or giant); surgical timing (ultra-early, early, delayed), and Intracerebral Hemorrhage (ICH) volume. For each parameter we calculated mean and standard deviation, covariance and relation coefficient (through the linear regression model).

The pCONus2 Neck-Bridging Device: Early Clinical Experience and Immediate Angiographic Results.

Treating wide-necked aneurysms is challenging for the interventional neuroradiologist. Recently, numerous devices dedicated to the treatment of these aneurysms have become available. We report our early experience using the pCONus2 device and present the technical success rate, clinical outcomes, and immediate angiographic occlusion rates. We performed a retrospective review of prospectively collected data to identify patients treated with the pCONus2 device between February 2015 and February2017. We identified 12 patients (10 females) treated with the pCONus2 device. The average patient age was56.6 ± 15.8 years (range, 13-71 years). The average aneurysm dome width was 8.83 ± 5.3 mm (range, 3.8-20mm), the average dome height was 7.23 ± 4.06 mm (range, 3.36-15 mm), and the average neck width was 5.88 ± 2.92 mm (range, 2.77-11 mm). The angulation of the aneurysm to the parent vessel varied between 0 and 78°(mean, 32.2°). Ten aneurysms were located in the anterior circulation, and 2 were in the posterior circulation. Immediate posttreatment angiography showed 11 aneurysms with modified Raymond-Roy classification (mRRC) grade I occlusion and 1 aneurysm with mRRC grade II occlusion. There were no deaths or hemorrhagic complications. Three patients developed small thrombi during treatment, all of whom were successfully treated with glycoprotein IIb/IIIa antagonists. Early angiographic follow-up data for 6 patients showed adequate aneurysm occlusion in 5 patients and aneurysm recanalization in 1patient. The early results on the use of the pCONus2 device suggest that it can be useful for treating wide-necked aneurysms; however, larger studies with longer-term follow-up data are needed.

Proximal Stenosis Is Associated with Rupture Status in Middle Cerebral Artery Aneurysms.

Hemodynamic factors impact cerebral aneurysm development and progression. Parent vessel architectural features, such as caliber, curvature, and angle, can affect downstream pressure and shear stress. To investigate the association between proximal parent vessel stenosis and aneurysm rupture status at the middle cerebral artery (MCA) bifurcation. Catheter 3-dimensional rotational angiographic datasets from 69 Japanese patients with MCA aneurysms (58 unruptured/11 ruptured) were analyzed. The narrowest cross-sectional area of the M1 segment was evaluated through equidistant cross-sectional plane cuts along the M1 length. The degree of stenosis relative to M1 size (StenosisIndex) and the distance from stenosis to the aneurysm neck (StenosisAnDist) were statistically evaluated. The effects of StenosisIndex and StenosisAnDist were determined in parametric aneurysm models with/without stenosis using computational fluid dynamic and fluid-structure interaction simulations. MCA harboring ruptured aneurysms had significantly greater StenosisIndex (0.31 ± 0.21 vs. 0.17 ± 0.14, P= 0.01), indicative of greater narrowing, and shorter StenosisAnDist (4.26 ± 1.91 vs. 6.94 ± 4.06 mm, P= 0.02) compared with unruptured aneurysms. Multivariate analysis combining StenosisIndex and StenosisAnDist resulted in P= 0.003, area under the curve= 0.81 (80% sensitivity, 74% specificity). Computational fluid dynamic and fluid-structure interaction simulations identified a synergetic effect of high stenosis and short StenosisAnDist in inducing greater aneurysm inflow velocity and deeper jet penetration, greater dome pressure, and greater tensile stress in the aneurysm wall. Ruptured status in bifurcation MCA aneurysms was associated with severity of proximal M1 stenosis and its proximity to the aneurysm neck, a novel risk factor, which acts by increasing aneurysm dome wall tension, and should be considered in investigations of rupture risk stratification.

Isolated abducens nerve palsy associated with subarachnoid hemorrhage: a localizing sign of ruptured posterior inferior cerebellar artery aneurysms.

OBJECTIVE Compressive cranial nerve syndromes can be useful bedside clues to the diagnosis of an enlarging intracranial aneurysm and can also guide subsequent evaluation, as with an acute oculomotor nerve (cranial nerve [CN] III) palsy that is presumed to be a posterior communicating artery aneurysm and a surgical emergency until proven otherwise. The CN VI has a short cisternal segment from the pontomedullary sulcus to Dorello's canal, remote from most PICA aneurysms but in the hemodynamic pathway of a rupturing PICA aneurysm that projects toward Dorello's canal. The authors describe a cranial nerve syndrome for posterior inferior cerebellar artery (PICA) aneurysms that associates subarachnoid hemorrhage (SAH) and an isolated abducens nerve (CN VI) palsy. METHODS Clinical and radiological data from 106 surgical patients with PICA aneurysms (66 ruptured and 40 unruptured) were retrospectively reviewed. Data from a group of 174 patients with other aneurysmal SAH (aSAH) were analyzed in a similar manner to control for nonspecific effects of SAH. Univariate statistical analysis compared incidence and risk factors associated with CN VI palsy in subarachnoid hemorrhage. RESULTS Overall, 13 (4.6%) of 280 patients had CN VI palsy at presentation, and all of them had ruptured aneurysms (representing 13 [5.4%] of the 240 cases of ruptured aneurysms). CN VI palsies were observed in 12 patients with ruptured PICA aneurysms (12/66 [18.1%]) and 1 patient with other aSAH (1/174 [0.1%], p < 0.0001). PICA aneurysm location in ruptured aneurysms was an independent predictor for CN VI palsy on multivariate analysis (p = 0.001). PICA aneurysm size was not significantly different in patients with or without CN VI palsy (average size 4.4 mm and 5.2 mm, respectively). Within the PICA aneurysm cohort, modified Fisher grade (p = 0.011) and presence of a thick cisternal SAH (modified Fisher Grades 3 and 4) (p = 0.003) were predictors of CN VI palsy. In all patients with ruptured PICA aneurysms and CN VI palsy, dome projection and presumed direction of rupture were directed toward the ipsilateral and/or contralateral Dorello's canal, in agreement with laterality of the CN palsy. In patients with bilateral CN VI palsies, a medial projection with extensive subarachnoid blood was observed near bilateral canals. CONCLUSIONS This study establishes a localizing connection between an isolated CN VI palsy, SAH, and an underlying ruptured PICA aneurysm. CN VI palsy is an important clinical sign in aSAH and when present on initial clinical presentation may be assumed to be due to ruptured PICA aneurysms until proven otherwise. The deficit may be ipsilateral, contralateral, or bilateral and is determined by the direction of the aneurysm dome projection and extent of subarachnoid bleeding toward Dorello's canal, rather than by direct compression.

Predictive anatomical factors for rupture in middle cerebral artery mirror bifurcation aneurysms

OBJECTIVE The aim of this study was to define predictive factors for rupture of middle cerebral artery (MCA) mirror bifurcation aneurysms. METHODS The authors retrospectively analyzed the data in patients with ruptured MCA bifurcation aneurysms with simultaneous presence of an unruptured MCA bifurcation mirror aneurysm treated in two neurosurgical centers. The following parameters were measured and analyzed with the statistical software R: neck, dome, and width of both MCA aneurysms-including neck/dome and width/neck ratios, shape of the aneurysms (regular vs irregular), inflow angle of both MCA aneurysms, and the diameters of the bilateral A1 and M1 segments and the frontal and temporal M2 trunks, as well as the bilateral diameter of the internal carotid artery (ICA). RESULTS The authors analyzed the data of 44 patients (15 male and 29 female, mean age 50.1 years). Starting from the usual significance level of 0.05, the Sidak-corrected significance level is 0.0039. The diameter of the measured vessels was statistically not significant, nor was the inflow angle. The size of the dome was highly significant (p = 0.0000069). The size of the neck (p = 0.0047940) and the width of the aneurysms (p = 0.0056902) were slightly nonsignificant at the stated significance level of 0.0039. The shape of the aneurysms was bilaterally identical in 22 cases (50%). In cases of asymmetrical presentation of the aneurysm shape, 19 (86.4%) ruptured aneurysms were irregular and 3 (13.6%) had a regular shape (p = 0.001). CONCLUSIONS In this study the authors show that the extraaneurysmal flow dynamics in mirror aneurysms are nonsignificant, and the aneurysmal geometry also does not seem to play a role as a predictor for rupture. The only predictors for rupture were size and shape of the aneurysms. It seems as though under the same conditions, one of the two aneurysms suffers changes in its wall and starts growing in a more or less stochastic manner. Newer imaging methods should enable practitioners to see which aneurysm has an unstable wall, to predict the rupture risk. At the moment one can only conclude that in cases of MCA mirror aneurysms the larger one, with or without shape irregularities, is the unstable aneurysm and that this is the one that needs to be treated.

310 Differences in Stump Pressures Between Ruptured and Un-Ruptured Intracranial Aneurysms

Abstract INTRODUCTION We present the largest prospective cohort of intra-saccular pressure recordings of ruptured and non-ruptured intracranial aneurysms. METHODS Aneurysmal dome pressure was collected using a standard 1.8 Fr micro-catheter which was navigated into the dome of the aneurysm under continuous roadmap and fluoroscopic guidance taking care to avoid placement against the wall and past the neck. Once in place, a transducer was attached to the proximal end of the micro-catheter to measure stump pressures for an estimated 60 seconds and only considered valid when clear systole and diastole profiles were observed. Transducer re-zeroing and line re-prepping was performed in the absence of systole and diastole profiles to confirm invalid data prior to data exclusion. RESULTS &gt;A prospective cohort of 38 patients were included in the study. 8 patients' data were discarded due to poor waveform during measurement. Of the remaining 30 patients, 14 presented with ruptured aneurysms while 16 were elective non-ruptured cases. The mean pulse pressure in non-ruptured cases was 21.7 with standard deviation of 17.0 compared to mean of 5.8 and standard deviation of 5.0 in ruptured cases. In addition the average systolic aneurysm pressure was 91% of the systolic blood pressure in non-ruptured cases compared to 78% in ruptured cases. CONCLUSION There is a significant difference noted in systolic and overall pulse pressures between ruptured and non-ruptured aneurysm groups with P = 0.05 and 0.005 respectively. This finding could be due to rupture effect phenomenon in which case this technique could aid in differentiating between ruptured and non-ruptured aneurysms. We hypothesize that lower aneurysm systolic and pulse pressures could be suggestive of low wall shear stress at the aneurysm dome which has been implicated in secondary inflammation of the aneurysm wall leading to aneurysmal rupture. This information could be important for risk stratification of non-ruptured intracranial aneurysms.

Microneurosurgical Clip Ligation of Acutely Ruptured Cerebral Aneurysm Immediately Preceded by Intentional Subtotal Endovascular Coil Embolization Under a Single Anesthesia: Observations Using a Deliberate Combined Sequential Treatment Strategy in 13 Cases.

Endovascular coil embolization and craniotomy with clip ligation are the 2 most commonly used treatments for ruptured cerebral aneurysm. Although coiling maintains the advantages of brevity and complete avoidance of brain retraction and manipulation, clipping offers the benefits of decompression of the injured brain and lower rates of aneurysm recurrence. Acombined, immediately sequential treatment strategy for acutely ruptured cerebral aneurysm that simultaneously maximizes the advantages of both techniques, while minimizing their respective disadvantages, may be a useful paradigm. To demonstrate the complementarity of clipping and coiling in acutely ruptured cerebral aneurysm. Patients with ruptured anterior circulation cerebral aneurysm standing to benefit from brain decompression were treated by a combination of coiling and microneurosurgery in rapid succession, under the same general anesthetic. Surgery consisted of clipping of the aneurysm via either craniotomy or craniectomy with expansion duraplasty in all cases, and ventriculostomy in selected cases. Coil embolization of the ruptured aneurysm was carried out rapidly and improved the efficiency of subsequent clipping by allowing early unequivocal identification of the aneurysm dome and decreased brain retraction, reducing risk of intraoperative rupture and obviating temporary occlusion. All aneurysms were shown eliminated by postoperative cerebral angiography. A deliberate combined treatment strategy that uses clipping immediately preceded by subtotal coiling under a single anesthetic may be ideal for selected ruptured cerebral aneurysms, takes advantage of the unique strengths of both techniques, makes both techniques easier, and maximizes opportunity for brain protection against delayed complications in the prolonged aftermath of aneurysmal subarachnoid hemorrhage.