Stent-Assisted Coiling May Prevent the Recurrence of Very Small Ruptured Intracranial Aneurysms: A Multicenter Study

OBJECTIVE

To evaluate the safety and efficacy of endovascular treatments, including stent-assisted coiling, of very small (≤3 mm), ruptured intracranial aneurysms.

METHODS

Ninety-three endovascularly treated patients with very small ruptured aneurysms were recruited from 4 high-volume centers between September 2010 and February 2014. Factors influencing procedural complications and outcomes were analyzed.

RESULTS

Fifty-one (54.8%) aneurysms were treated by stent-assisted coiling, 41 (44.1%) by coiling alone, and 1 (1.1%) by balloon-assisted coiling. Intraprocedural or postprocedural complications occurred in 13 patients (14.0%): coil migration in 1, intraprocedural rupture in 1, hydrocephalus in 6, and ischemic event in 1. No tested factor was able to predict procedural complications. Angiographic follow-up of 67 aneurysms (72%) revealed recurrence in 5 patients (7.5%). One recurrent case was treated initially by stent-assisted coiling and the remaining four by coiling alone (P = 0.044). Multivariate regression analysis showed that coiling alone was significantly associated with aneurysm recurrence (odds ratio, 13.8; 95% confidence interval, 1.1-175.3; P = 0.043).

CONCLUSIONS

Endovascular treatment of very small ruptured aneurysms was safe and effective and was not associated with a high rate of intraprocedural rupture. Treatment with the use of stents significantly lowered the recurrence rate without additional risks.

Global Gene Expression Patterns and Somatic Mutations in Sporadic Intracranial Aneurysms

BACKGROUND

High-throughput sequencing technologies can expand our understanding of the pathologic basis of intracranial aneurysms (IAs). Our study was aimed to decipher the gene expression signature and genetic factors associated with IAs.

METHODS

We determined the gene expression levels of 3 cases of IAs by RNA sequencing. Bioinformatics analysis was conducted to identify the differentially expressed genes (DEGs) and uncover their biological function. In addition, whole genome sequencing was performed on an additional 6 cases of IAs to detect the potential somatic alterations in DEGs.

RESULTS

Compared with the normal arterial tissue, 1709 genes were differentially expressed in IAs arterial tissue. The most significantly up-regulated gene and down-regulated gene, H19 and HIST1H3J, may be essential for tumorigenesis of IAs. Hub protein of IKBKG in protein-protein interaction network was probably involved in the inflammation process in aneurysms. Another 2 hub proteins, ACTB and MKI67IP, as well as up-regulated genes, might be abnormally activated in aneurysms and involved in the pathogenesis of IAs. Further whole genome sequencing and filtering yielded 4 candidate somatic single nucleotide variants including MUC3B, and BLM may be involved in the pathogenesis of IAs. Even though, our results do not support the hypothesis of somatic mutations occurred in the DEGs.

CONCLUSIONS

Two-dimensional genomic data from transcriptome and whole genome sequencing indicated that no somatic mutations occurred in DEGs. In addition, 3 DEGs (IKBKG, ACTB, and MKI67IP) and 2 mutant genes (MUC3B and BLM) were essential in IAs.

PulseRider for Treatment of Wide-Neck Bifurcation Intracranial Aneurysms: 6-Month Results

BACKGROUND/OBJECTIVE

PulseRider is a new endovascular stent dedicated to treat bifurcation intracranial aneurysms with a wide neck. Our purpose was to evaluate 6-month clinical and anatomic results of the device when used to facilitate endovascular coiling of wide-neck bifurcation aneurysms.

METHODS

Unruptured intracranial aneurysms coiled with PulseRider, in 6 European centers and 1 U.S. center, were retrospectively reviewed from June 2014 to October 2015. Immediate and 6-month results were evaluated independently by using the Raymond classification scale. Recanalization was defined as worsening, and progressive thrombosis was defined as improvement on the Raymond scale.

RESULTS

Nineteen patients (10 women, 9 men; mean age, 63 years) harboring 19 bifurcation aneurysms (mean dome size, 8.8 mm; mean neck size, 5.8 mm) were included. Immediate angiographic outcome showed 11 complete aneurysm occlusions, 6 neck remnants, and 2 residual aneurysms. Follow-up at 6 months, obtained in all patients, included 12 complete aneurysm occlusions (63.1%), 6 neck remnants (31.6%), and 1 residual aneurysm (5.3%). Adequate occlusion (defined as complete occlusion and neck remnant combined) was observed in 94.7%. Progressive thrombosis was observed in 2 cases (10.6%) and recanalization in 1 case (5.3%). There was no in-stent stenosis or jailed branch occlusion. No bleeding was observed during the follow-up period. Permanent morbidity rate was 5.3% (1/19), and the mortality rate was 0% at 6 months.

CONCLUSIONS

The PulseRider allows endovascular treatment of wide-neck bifurcation intracranial aneurysms. Larger series are needed to confirm our preliminary results.

Low wall shear stress is associated with the rupture of intracranial aneurysm with known rupture point: case report and literature review

Background

Few previous hemodynamic studies demonstrated the detailed features of rupture point of intracranial aneurysms. The hemodynamic simulation for the case that ruptured during angiography was even rare. In the present study, we studied the hemodynamic characteristics of a posterior communicating artery segment aneurysm that ruptured during angiography and detailed the hemodynamic features at the rupture point.

Case presentation

One 64-years-patient was 60–69 years old and suffered a subarachnoid hemorrhage within 24 h. Standard digital subtraction angiography and three-dimensional (3D) rotational angiography were performed and an 8 mm left posterior communicating artery segment aneurysm was found. The patient had a seizure immediately following 3D angiography for about 40 s and the immediate follow-up angiography showed contrast extravasation from the tip of identified aneurysms. The consequent vital sign of the patient became unstable. Urgent embolization under general anesthesia was planned, but the relatives refused interventional operation considering the high risk of procedure and poor condition of the patient. The computational fluid dynamic (CFD) method was used to evaluate the hemodynamic characteristics at rupture point, and the results showed that the rupture point was associated with markedly low wall shear stress and high oscillatory shear index without flow impingement.

Conclusions

We present a rare case of which the rupture site was identified during angiography. The hemodynamic simulations revealed that the rupture point was associated with markedly low WSS and high OSI without flow impingement. The result may be unique to this particular aneurysm; however, our findings provide insight into the hemodynamics of rupture point.

Electronic supplementary material

The online version of this article (doi:10.1186/s12883-016-0759-0) contains supplementary material, which is available to authorized users.

Comparison between smaller ruptured intracranial aneurysm and larger un-ruptured intracranial aneurysm: gene expression profile analysis

As it grows in size, an intracranial aneurysm (IA) is prone to rupture. In this study, we compared two extreme groups of IAs, ruptured IAs (RIAs) smaller than 10 mm and un-ruptured IAs (UIAs) larger than 10 mm, to investigate the genes involved in the facilitation and prevention of IA rupture. The aneurismal walls of 6 smaller saccular RIAs (size smaller than 10 mm), 6 larger saccular UIAs (size larger than 10 mm) and 12 paired control arteries were obtained during surgery. The transcription profiles of these samples were studied by microarray analysis. RT-qPCR was used to confirm the expression of the genes of interest. In addition, functional group analysis of the differentially expressed genes was performed. Between smaller RIAs and larger UIAs, 101 genes and 179 genes were significantly over-expressed, respectively. In addition, functional group analysis demonstrated that the up-regulated genes in smaller RIAs mainly participated in the cellular response to metal ions and inorganic substances, while most of the up-regulated genes in larger UIAs were involved in inflammation and extracellular matrix (ECM) organization. Moreover, compared with control arteries, inflammation was up-regulated and muscle-related biological processes were down-regulated in both smaller RIAs and larger UIAs. The genes involved in the cellular response to metal ions and inorganic substances may facilitate the rupture of IAs. In addition, the healing process, involving inflammation and ECM organization, may protect IAs from rupture.

Arterial aneurysms associated with arteriovenous malformations of the brain: classification, incidence, risk of hemorrhage, and treatment-a systematic review

BACKGROUND

Aneurysms associated with brain arteriovenous malformations (bAVMs) influence the natural history of these lesions and pose important therapeutic challenges. However, the epidemiology, natural history, and appropriate management of the aneurysms associated with bAVMs are not completely understood due to the paucity of large and uniform studies. We performed a systematic review of published series examining the association between aneurysms and bAVMs with the purpose of clarifying the prevalence, risk of hemorrhage, and appropriate management of these lesions.

METHOD

PRISMA/MOOSE guidelines were followed. We conducted a comprehensive literature search of three databases (PubMed, Ovid MEDLINE, and Ovid EMBASE) on aneurysms associated with bAVMs. Only studies examining consecutive case series of aneurysms associated with bAVMs were included. From the collected studies, we extracted data regarding prevalence of bAVM-associated aneurysms, risk of aneurysm rupture in relation to bAVM location and aneurysm characteristics, and treatment-related outcomes.

RESULTS

Our systematic review included 44 articles with a total of 10,093 bAVMs. The proportion of bAVMs with an associated aneurysm was 20.2 % (95 % CI = 19.4-20.9 %). Among ruptured bAVMs with associated aneurysms, the aneurysm was the source of hemorrhage in 49.2 % (95 % CI = 43.7-54.7 %) of cases. Flow-related aneurysms were the most common source of aneurysm rupture (78.5 %, 95 % CI = 70.6-84.9 %). Infratentorial bAVM-associated aneurysms presented a higher risk of rupture (60 %, 95 % CI = 47.4-71.9 %) when compared with supratentorial lesions (29 %, 95 % CI = 21.4-38.5 %). Endovascular treatment of aneurysms associated with bAVMs had a cure rate of 80.0 % (95 % CI = 73.3-85.3 %), complication rate of 8.7 % (95 % CI = 5.5-13.1 %), and a good neurological outcome rate of 78.8 % (95 % CI = 72.5-83.9 %).

CONCLUSIONS

Twenty percent of bAVMs harbored arterial aneurysms. The presence of aneurysm increases the risk of bleeding of the bAVM, especially when flow-related or infratentorially located. Aneurysms associated with bAVMs should be treated promptly. Selective endovascular treatment of bAVM-associated aneurysms appears safe and effective.

The "ICG Entrapment Sign" in Cerebral Aneurysm Surgery Assisted by Indocyanine Green Videoangiography

BACKGROUND

Indocyanine green videoangiography (ICG-VA) after clipping can be misleading in evaluating aneurysm exclusion when the dye is injected before clipping. This is due to indocyanine green (ICG) entrapment by the clip blades in the aneurysm dome.

METHODS

We examined the intraoperative findings of 7 patients presenting ICG entrapment. In all cases, the clipped aneurysms were opened intraoperatively at the end of the procedure to confirm aneurysm exclusion.

RESULTS

In 4 cases ICG entrapment was caused by dye injection before clipping for the surgical strategy and in 3 cases because the clip was repositioned based on ICG-VA findings. In all cases, the final sac opening confirmed that the dye entrapment indicated complete aneurysm exclusion. In our experience ICG entrapment avoided a second ICG injection in 2 cases and yielded a better understanding of the videoangiographic findings in 5 patients.

CONCLUSIONS

The "ICG entrapment sign" can be used intraoperatively as an indirect sign of excluded aneurysm and can be helpful in the decision-making process for aneurysm treatment when ICG-VA is performed before clipping.

Uncertainty quantification of wall shear stress in intracranial aneurysms using a data-driven statistical model of systemic blood flow variability

Adverse wall shear stress (WSS) patterns are known to play a key role in the localisation, formation, and progression of intracranial aneurysms (IAs). Complex region-specific and time-varying aneurysmal WSS patterns depend both on vascular morphology as well as on variable systemic flow conditions. Computational fluid dynamics (CFD) has been proposed for characterising WSS patterns in IAs; however, CFD simulations often rely on deterministic boundary conditions that are not representative of the actual variations in blood flow. We develop a data-driven statistical model of internal carotid artery (ICA) flow, which is used to generate a virtual population of waveforms used as inlet boundary conditions in CFD simulations. This allows the statistics of the resulting aneurysmal WSS distributions to be computed. It is observed that ICA waveform variations have limited influence on the time-averaged WSS (TAWSS) on the IA surface. In contrast, in regions where the flow is locally highly multidirectional, WSS directionality and harmonic content are strongly affected by the ICA flow waveform. As a consequence, we argue that the effect of blood flow variability should be explicitly considered in CFD-based IA rupture assessment to prevent confounding the conclusions.

Evaluation of Pipeline Flex delivery system for the treatment of unruptured aneurysms

INTRODUCTION

Refinements in endovascular technology have revolutionized the treatment of intracranial aneurysms (IAs) with the development of flow-diversion technology. The first generation of the Pipelin Embolization Device (PED) has demonstrated its safety and efficacy. However, the deployment technique was a difficult task that often led to complex maneuvers. The Pipeline Flex Embolization Device (PED Flex) is the second generation and its introduction has arrived with high expectations due to a completely redesigned delivery system that intends to overcome deployment difficulties seen in the previous generation. Areas covered: Preclinical studies, mechanism of action of flow-diverters, technical aspects and deployment system of the PED Flex, and clinical outcomes with both PED generations. Expert commentary: Flow diversion has allowed us to treat lesions that would be otherwise challenging for surgical clipping or unsuitable for other endosaccular strategies. Although the experience with PED Flex is limited, initial results suggest its safety and short-term efficacy.

Wall enhancement on high-resolution magnetic resonance imaging may predict an unsteady state of an intracranial saccular aneurysm

INTRODUCTION

The aneurysm wall has been reported to play a critical role in the formation, development, and even rupture of an aneurysm. We used high-resolution magnetic resonance imaging (HRMRI) to investigate the aneurysm wall in an effort to identify evidence of inflammation invasion and define its relationship with aneurysm behavior.

METHODS

Patients with intracranial aneurysms who were prospectively evaluated using HRMRI between July 2013 and June 2014 were enrolled in this study. The aneurysm's wall enhancement and evidence of inflammation invasion were determined. In addition, the relationship between aneurysm wall enhancement and aneurysm size and symptoms, including ruptured aneurysms, giant unruputred intracranial aneurysms (UIAs) presenting as mass effect, progressively growing aneurysms, and aneurysms associated with neurological symptoms, was statistically analyzed.

RESULTS

Twenty-five patients with 30 aneurysms were available for the current study. Fourteen aneurysms showed wall enhancement, including 6 ruptured and 8 unruptured aneurysms. Evidence of inflammation was identified directly through histological studies and indirectly through intraoperative investigations and clinical courses. The statistical analysis indicated no significant correlation between aneurysm wall enhancement and aneurysm size. However, there was a strong correlation between wall enhancement and aneurysm symptoms, with a kappa value of 0.86 (95 % CI 0.68-1).

CONCLUSIONS

Aneurysm wall enhancement on HRMRI might be a sign of inflammatory change. Symptomatic aneurysms exhibited wall enhancement on HRMRI. Wall enhancement had a high consistent correlation of symptomatic aneurysms. Therefore, wall enhancement on HRMRI might predict an unsteady state of an intracranial saccular aneurysm.

LVIS Stent Versus Enterprise Stent for the Treatment of Unruptured Intracranial Aneurysms

OBJECTIVE

This retrospective study compared clinical and angiographic outcomes between LVIS and Enterprise stents.

MATERIALS AND METHODS

From November 2014 to December 2015, total 190 patients with 208 unruptured intracranial aneurysms were coiled assisted by LVIS and Enterprise stents. Procedure-related complications, clinical outcomes, and angiographic results were analyzed retrospectively.

RESULTS

A total of 92 patients with 96 aneurysms received LVIS stents and 98 patients with 112 aneurysms were treated with Enterprise stents. Procedure-related complications occurred in 10.9% of patients (2 hemorrhagic events and 8 thromboembolic events) in the LVIS stents group whereas 16.3% (1 hemorrhage, 1 mass effect, and 14 thromboembolic events) in the Enterprise stents group. No statistical significant differences in thromboembolic (P = 0.263), hemorrhagic complications (P = 0.611), and favorable clinical outcomes (modified Rankin Scores of 0-2) (P = 0.379) were found between 2 groups. A greater initial complete or near-complete obliteration was found in the LVIS stents group compared with the Enterprise stents group (96.9% vs. 88.4%, P = 0.034). Larger aneurysm size (P = 0.048) was an independent predictor of procedure-related complications in univariate analysis.

CONCLUSIONS

Compared with Enterprise stents, LVIS stents may achieve greater complete or near-complete occlusion rate. There was no significant difference in procedural-related complications and clinical outcomes between LVIS and Enterprise stents.

Occlusion assessment of intracranial aneurysms treated with the WEB device

INTRODUCTION

The Woven EndoBridge (WEB) system is an innovative device under evaluation for its capacity to treat wide-neck bifurcation intracranial aneurysms. The purpose of this study is to evaluate the use of the different occlusion scales available in clinical practice.

METHODS

Seven WEB-experienced neurointerventionalists were provided with 30 angiographic follow-up data sets and asked to grade each evaluation point according to the Bicêtre Occlusion Scale Score (BOSS), firstly based on DSA images only then using additional C-Arm VasoCT analysis. This BOSS evaluation was then converted into the WEB Occlusion Scale (WOS) and into a dichotomized scale (complete occlusion or not). To estimate the inter-rater agreement among the seven raters, an overall kappa coefficient [1] and its standard error (SE) were computed.

RESULTS

Using the five-grade BOSS, raters showed "moderate" agreement (kappa = 0.56). Using the three-grade WOS, agreement appeared slightly better (kappa = 0.59). Strongest inter-rater agreement was observed with a dichotomized version of the scale (complete occlusion or not), which enabled an "almost perfect" agreement (kappa = 0.88). VasoCT consistently enhanced the agreement particularly with regards depicting intra-WEB residual filling.

CONCLUSION

The WOS is a consistent means to angiographically evaluate the WEB device efficiency. But the five-grade BOSS scale allows to identify aneurysm subgroups with differing risks of recurrence and/or rehemorrhage, which needs to be separated especially at the initial phase of evaluation of this innovative device. The additional use of VasoCT allows better inter-rater agreement in evaluating occlusion and specially in depicting intra-WEB persistent filling.

Analysis of Multiple Intracranial Aneurysms with Different Outcomes in the Same Patient After Endovascular Treatment

BACKGROUND

Aneurysm recanalization after coiling, with or without stent assistance, is a major issue in the endovascular management of intracranial aneurysms. Multiple intracranial aneurysms with different outcomes after endovascular treatment may represent a useful disease model in which patient-specific risk factors can be balanced to investigate possible features linked to aneurysm recanalization. In the present study, we evaluated the impact of aneurysm-specific, treatment-related, and hemodynamics-related factors on multiple aneurysms and to explore the reason why one aneurysm recanalized and the other did not.

METHODS

Between 2010 and 2015, 763 multiple intracranial aneurysms in 326 patients were diagnosed by digital subtraction angiography. We retrospectively collected and analyzed 13 pairs of multiple aneurysms with different outcomes (recanalized or stable) in the same patient. Patient-specific models were constructed and analyzed by a computational fluid dynamics method. The virtual stent deployment method was used, and the coils were simulated by a porous medium model. Factors were evaluated for significance with respect to recanalization.

RESULTS

Aneurysm size (P = 0.021), neck width (P = 0.027), ruptured aneurysms (P = 0.002), reduction ratio of averaged velocity (P = 0.008), and wall shear stress (P = 0.024) were significantly associated with aneurysm recanalization. By contrast, the aneurysm location, all of treatment-related factors (packing density, duration of follow-up, stent use, initial angiographic result) and the reduction ratio of averaged pressure were not significantly associated (P > 0.05).

CONCLUSIONS

Small aneurysm size and neck width, unruptured aneurysm, and perianeurysmal hemodynamics with marked reduction may be important factors associated with the midterm durability of aneurysm embolization.

A Multicenter Analysis of Computed Tomography Angiography Alone Versus Digital Subtraction Angiography for the Surgical Treatment of Poor-Grade Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Poor-grade aneurysmal subarachnoid hemorrhage (aSAH) is associated with increased intracranial pressure, and these patients are unstable with a high risk of rebleeding. Computed tomography angiography (CTA) has been proposed as an examination tool for the rapid detection of ruptured aneurysms. We aimed to determine the safety and efficacy of CTA alone for surgical treatment of poor-grade aSAH compared with digital subtraction angiography (DSA).

METHODS

We conducted a multicenter retrospective analysis of 144 patients with poor-grade aSAH who underwent surgical treatment for 2 different cohorts. Patients were grouped into CTA alone and DSA groups. Baseline characteristics, postoperative complications, and clinical outcomes at discharge and at last follow-up were compared between the 2 groups. Multivariate logistic regression models were used to assess the association between CTA alone and clinical outcomes after we adjusted for potential confounders.

RESULTS

Of the 116 patients included, 42 (36.2%) patents received CTA alone and 74 patients (63.7%), including 12 patients with CTA and DSA and 62 patients with DSA alone, received DSA before surgical treatment. Patients with larger ruptured aneurysms (P = 0.006), aneurysm sizes of larger than 5 mm (P = 0.025), presence of single aneurysms (P = 0.018), and presence of intraventricular hemorrhage (P = 0.019) more often received CTA alone. All ruptured aneurysms were clipped successfully during surgery. There were no statistically significant differences in postoperative complications and clinical outcomes between the 2 groups.

CONCLUSIONS

Although CTA alone can be safely and effectively used in most patients requiring surgical treatment, additional DSA may be considered in patients with smaller ruptured aneurysms or in those with multiple aneurysms.

Natural History of Unruptured Intracranial Aneurysms : A Retrospective Single Center Analysis

Objective

We conducted a retrospective cohort study to elucidate the natural course of unruptured intracranial aneurysms (UIAs) at a single institution.

Methods

Data from patients diagnosed with UIA from March 2000 to May 2008 at our hospital were subjected to a retrospective analysis. The cumulative and annual aneurysm rupture rates were calculated. Additionally, risk factors associated with aneurysmal rupture were identified.

Results

A total of 1339 aneurysms in 1006 patients met the inclusion criteria. During the follow-up period, 685 aneurysms were treated before rupture via either an open surgical or endovascular procedure. Six hundred fifty-four UIAs were identified and not repaired during the follow-up period. The mean UIA size was 4.5±3.2 mm, and 86.5% of the total UIAs had a largest dimension <7 mm. Among these UIAs, 18 ruptured at a median of 1.6 years (range : 27 days to 9.8 years) after day 0. The annual rupture risk during a 9-year follow-up was 1.00%. A multivariate Cox proportional hazards analysis revealed that the aneurysm size and a history of subarachnoid hemorrhage (SAH) were statistically significant risk factors for rupture. For an aneurysms smaller than 7 mm in the absence of a history of SAH, the annual rupture risk was 0.79%.

Conclusion

In our study, the annual rupture risk for UIAs smaller than 7 mm in the absence of a history of SAH was higher than that of Western populations but similar to that of the Japanese population.

Effects of preventive surgery for unruptured intracranial aneurysms on attention, executive function, learning and memory: a prospective cohort study

BACKGROUND

We prospectively evaluated the effects of preventive surgery for unruptured intracranial aneurysms on attention, executive function, learning and memory.

METHODS

Between March 2012 and June 2013, 56 patients were recruited for this study. Fifty-one patients met the inclusion criteria and were enrolled. Inclusion criteria were as follows: (1) age ≤65 years and (2) planned microsurgery or endovascular surgery for unruptured intracranial aneurysm. Exclusion criteria were as follows: (1) preoperative intelligence quotient <80 (n = 3); (2) initial modified Rankin scale ≥1 (n = 1); (3) loss to follow-up (n = 1). An auditory controlled continuous performance test (ACCPT), word-color test (WCT) and verbal learning test (VLT) were performed before and after (6 months) preventive surgery.

RESULTS

ACCPT (attention), WCT (executive function) and VLT (learning and memory) scores did not change significantly between the pre- and postoperative evaluations. The ACCPT, WCT, total VLT scores (verbal learning) and delayed VLT scores (memory) did not differ significantly between patients undergoing microsurgery and those undergoing endovascular surgery. However, ACCPT, WCT and delayed VLT scores decreased postoperatively in patients with leukoaraiosis on preoperative FLAIR images (OR 9.899, p = 0.041; OR 11.421, p = 0.006; OR 2.952, p = 0.024, respectively).

CONCLUSIONS

Preventive surgery for unruptured intracranial aneurysms did not affect attention, executive function, learning or memory. However, patients with leukoaraiosis on FLAIR images might be prone to deficits in attention, executive function and memory postoperatively, whereas learning might not be affected.

Stem Cells as a Potential Adjunctive Therapy in Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

Despite advances in the management of subarachnoid hemorrhage, a considerable proportion of patients are still left with severe and disabling long-term consequences. Unfortunately, there are limited therapeutic options to counteract the sequelae following the initial insult. The role of stem cells has been studied in the treatment of various diseases. The goal of this study was to provide a literature review regarding the potential advantages of stem-cell therapy to counteract or minimize the sequelae of aneurysmal subarachnoid hemorrhage.

METHODS

PubMed, Google Scholar, and ClinicalTrials.gov searches were conducted to incorporate pertinent studies that discussed stem cell use in the management of subarachnoid hemorrhage. Included articles were subjected to data extraction for the synthesis of the efficacy of stem-cell therapy.

RESULTS

Four preclinical studies with 181 animal model subjects (44 mice, 137 rats) were incorporated in our review. Endovascular punctures (65%) and blood injections in subarachnoid spaces (17%) were used to induce hemorrhage models. Stem cells were administered intravenously (3.0 × 10(6) cells) or intranasally (1.5 × 10(6) cells). According to literature, mesenchymal cell therapy significantly (p<0.05) induces stem-cell migration to lesion sites, decreases associated neural apoptosis and inflammation, improves ultrastructural integrity of cerebral tissue, and aids in improving sensorimotor function post subarachnoid hemorrhage.

CONCLUSION

Stem cells, particularly mesenchymal stem cells, have shown promising cellular, morphological, and functional benefits in animal models suffering from induced subarachnoid hemorrhages. However, further studies are warranted to elucidate the full effects of stem-cell therapy for aneurysmal subarachnoid hemorrhage.

Flow Dynamics of Aneurysm Growth and Rupture: Challenges for the Development of Computational Flow Dynamics as a Diagnostic Tool to Detect Rupture-Prone Aneurysms

Saccular intracranial aneurysm (sIA) is a relatively common disease that can potentially cause a devastating, life-threatening intracranial hemorrhage. Many sIAs never rupture and thus do not necessitate interventions, making the detection of rupture-prone sIAs a very relevant clinical problem. Moreover, because currently available methods to prevent sIA rupture have significant risks of morbidity and mortality, diagnostic tools that can predict imminent rupture and help plan proper timing of prophylactic interventions, can improve patient care. Hemorrhage from an sIA occurs when hemodynamic stress exceeds sIA wall strength. Computational fluid dynamics (CFD) is a tool with which the hemodynamic stress to which the sIA wall is exposed can be determined non-invasively. Studies using CFD in sIAs have demonstrated associations of wall shear stress (WSS) with aneurysm growth, fragile sIA wall, and sIA rupture; these studies show the potential of CFD as a diagnostic tool. This review discusses the limitations of CFD and of the studies performed, and what needs to be done in order to develop CFD into a useful diagnostic tool to determine aneurysm-specific rupture risk.

Endovascular coiling of small intracranial aneurysms using a very soft bare platinum coil: A comparison of the packing performance of new and old HyperSoft® helical coils

AIMS

Soft and small coils are known to be appropriate for the treatment of small aneurysms. The purpose of this study was to determine whether the new HyperSoft® helical coil, which is softer and smaller than its predecessors, has any effect on the packing performance in a matched-pair study with an old HyperSoft® helical coil.

MATERIALS AND METHODS

Thirty-six consecutive patients harboring 43 cerebral aneurysms treated with new HyperSofts were included in this study. Forty-one aneurysms treated with old HyperSofts were identified from our database as matched controls based on similar volumes and locations. Packing attenuation, adverse events during the procedures, and angiographic occlusions were observed and compared between the two groups.

RESULTS

The mean packing density was significantly higher in the new HyperSoft® group compared to the control group (35.5% vs. 26.9%), and a larger proportion of the aneurysms embolized with the 1.5 mm size coil, which has higher packing density. There was no difference in immediate and midterm angiographic outcomes. There was no difference in the rate of intraprocedural perforation, but there was no intraprocedural rupture related to the 1.5 mm coil.

CONCLUSIONS

The use of new HyperSoft® helical coils allows higher packing density comparable with the old technology. New HyperSoft® coils, especially those with 1.5 mm loop diameter, can be expected to fill smaller residual spaces in small aneurysms and may be helpful in preventing recanalization.

Cell Therapy for Intracranial Aneurysms: A Review

One in five patients undergoing endovascular coiling (the current standard of care for treating intracranial aneurysms) experience a recurrence of the aneurysm as a result of improper healing. Recurrence remains the only major drawback of the coiling treatment and has been the focus of many studies over the last two decades. Cell therapy, a novel treatment modality in which therapeutic cells are introduced to the site of the injury to promote tissue regeneration, has opened up new possibilities for treating aneurysms. The healing response that ensues aneurysm embolization includes several cellular processes that can be targeted with cell therapy to prevent the aneurysm from recurring. Ten preclinical studies involving cell therapy to treat aneurysms were published between 1999 and 2014. In this review, we summarize the results of these studies and discuss advances, shortcomings, and the future of cell therapy for intracranial aneurysms.

Treatment strategies for dissecting aneurysms of the posterior cerebral artery

BACKGROUND

Dissecting aneurysms of the posterior cerebral artery (PCA) are rare and difficult to treat because of their deep and unfamiliar locations and unusual shapes. Although several treatment modalities have been proposed, none have generated satisfying results. Our experiences with PCA-dissecting aneurysms are reviewed and the treatment strategies discussed.

METHODS

All consecutive patients with PCA-dissecting aneurysm who were treated in a tertiary referral hospital between January 1998 and March 2014 were identified by retrospective review. Their clinical characteristics, radiological findings, treatment modalities and outcomes were documented.

RESULTS

Of the 21 patients with 21 PCA-dissecting aneurysms, 9 had subarachnoid hemorrhage and 3 had acute infarction of the thalamus at presentation. The aneurysms involved P1 (n = 4), the P1-2 junction (n = 3), mid-P2 (n = 6), P2A (n = 3), P2P (n = 1) and the P2-3 junction (n = 4). The aneurysm shapes were as follows: fusiform (n = 12), partially thrombosed (n = 8) and blood blister-like aneurysms (n = 1). The mean size was 16.6 ± 9.7 mm. Parent artery occlusion (PAO) without bypass (n = 15), PAO with bypass (n = 2), stent-assisted endosaccular coiling (n = 3) and stent placement only (n = 1) were performed. All three patients who underwent stent-assisted endosaccular coiling and the single patient who underwent PAO without bypass developed aneurysm recurrence. Six of the ten patients who received a PAO without a balloon test occlusion (BTO) experienced PCA territory infarction, whereas only one of the five patients who received a PAO after passing the BTO experienced an infarction.

CONCLUSIONS

PAO for PCA-dissecting aneurysm was effective in preventing recurrence. In addition, BTO before PAO was helpful in identifying candidates who truly needed surgical revascularization.

Life-Threatening Cerebral Hematoma Owing to Aneurysm Rupture

OBJECTIVE

To refine the surgical indications of surgery for life-threatening cerebral hematomas caused by aneurysm rupture, through the analysis of possible outcome predictors.

METHODS

Forty-nine consecutive patients requiring prompt clot evacuation were retrospectively reviewed. In all cases, the hematoma was equal to or greater than 60 mL. The bleeding aneurysm was located on the middle cerebral artery in 26 cases, on the internal carotid artery in 10 cases, and on the anterior cerebral artery in 13 cases; four aneurysms were giant. Six patients underwent aneurysm coiling followed by clot removal, whereas 43 patients were managed by concomitant clot evacuation and aneurysm clipping. The main clinical and radiologic features, the management paths and the treatment modalities were correlated with the outcomes. A statistical analysis was conducted.

RESULTS

Overall mortality was 32.6%, severe morbidity was 22.4% and 22 patients (44.8%) achieved favorable results. The short-term results were more significantly influenced by the radiological parameters than by the initial clinical conditions. The prognostic weight of the radiologic findings was partially lost for six-month results, whereby management factors gained in importance.

CONCLUSIONS

The bleeding severity was strongly determinant for early mortality. However, if patients can survive the initial crucial phase, their chances of a favorable outcome are not negligible. Further improvement may be possible through better patient selection and the identification of nonsalvageable subjects.

Evaluation of a clip-reinforced wrapping technique with collagen-impregnated Dacron for intracranial aneurysms inaccessible to other treatment

OBJECTIVE

To describe our clip-reinforced wrapping technique (CRW) with collagen-impregnated Dacron and report our experience in intracranial aneurysms (IA) untreatable by coil embolization (CE) or surgical clipping (SC).

METHODS

Between July 2003 and November 2010, CRW was performed on 20 IAs in 18 patients using a collagen-impregnated Dacron fabric (Hemashield(®), USA) fixed with a clip around the parent vessel and the IA.

RESULTS

Two patients (11%) died of complications from their subarachnoid hemorrhage and preexisting conditions. In the remaining 16 patients, after an average follow-up of 45 months (min: 27, max: 77), 16 (89%) out of the 18 treated aneurysms were no longer visible and two were reduced and stable.

CONCLUSION

Our preliminary results suggest that CRW with Hemashield could be an accurate and safe alternative technique for some IA without any other treatment option.

IMPLICATIONS

Description of an alternative surgical technique for otherwise untreatable intracranial aneurysms.

3D bone subtraction CT angiography for the evaluation of intracranial aneurysms: a comparison study with 2D bone subtraction CT angiography and conventional non-subtracted CT angiography

BACKGROUND

Bone subtraction computed tomography angiography (BSCTA) is better able to facilitate the detection of intracranial aneurysms adjacent to bone structures compared to conventional non-subtracted CTA (CNSCTA). However, the comparison of the diagnostic accuracy of three-dimensional (3D) and two-dimensional (2D) BSCTA and conventional CTA in evaluating intracranial aneurysms remains unclear.

PURPOSE

To evaluate whether 3D BSCTA has a superior diagnostic accuracy to those of 2D BSCTA and CNSCTA in a single center with the same instrument.

MATERIAL AND METHODS

Sixty-three patients received 3D BSCTA, 2D BSCTA, and NSCTA for the detection and treatment planning of suspected intracranial aneurysms. The angiography readouts were reviewed by two independent radiologists. The sensitivity of CTA in detecting aneurysm was analyzed on a per-aneurysm and per-patient basis, using 3D digital subtraction angiography (DSA) and surgical findings as the gold standard. The potential of endovascular treatment or surgical clipping was also assessed based on information provided by the CTA.

RESULTS

A total of 66 aneurysms were detected in 54 patients. The overall sensitivity, specificity, positive, and negative predictive values of 3D BSCTA were all 100%, and these values for 2D BSCTA were 98.1%, 100%, 100%, and 90%, respectively. The total sensitivity, specificity, positive, and negative predictive values of CNSCTA were 94.4%, 100%, 100%, and 75%, respectively. Finally, 100%, 98.1%, and 85.2% patients received appropriate treatment decisions after 3D BSCTA, 2D BSCTA, and CNSCTA imaging, respectively.

CONCLUSION

3D BSCTA has a higher sensitivity for the detection of small aneurysms and aneurysms adjacent to bone compared to 2D BSCTA or CNSCTA, which were still able to obtain sufficient information for the detection of intracranial aneurysms and therapeutic decision-making.

Influence of Parent Artery Segmentation and Boundary Conditions on Hemodynamic Characteristics of Intracranial Aneurysms

PURPOSE

The purpose of this study is to explore the influence of segmentation of the upstream and downstream parent artery and hemodynamic boundary conditions (BCs) on the evaluated hemodynamic factors for the computational fluid dynamics (CFD) analysis of intracranial aneurysms.

MATERIALS AND METHODS

Three dimensional patient-specific aneurysm models were analyzed by applying various combinations of inlet and outlet BCs. Hemodynamic factors such as velocity pattern, streamline, wall shear stress, and oscillatory shear index at the systolic time were visualized and compared among the different cases.

RESULTS

Hemodynamic factors were significantly affected by the inlet BCs while there was little influence of the outlet BCs. When the inlet length was relatively short, different inlet BCs showed different hemodynamic factors and the calculated hemodynamic factors were also dependent on the inlet length. However, when the inlet length (L) was long enough (L>20D, where D is the diameter of inlet section), the hemodynamic factors became similar regardless of the inlet BCs and lengths. The error due to different inlet BCs was negligible. The effect of the outlet length on the hemodynamic factors was similar to that of the inlet length.

CONCLUSION

Simulated hemodynamic factors are highly sensitive to inlet BCs and upstream parent artery segmentation. The results of this work can provide an insight into how to build models and to apply BCs for more accurate estimation of hemodynamic factors from CFD simulations of intracranial aneurysms.

[Intracranial aneurysms and their clinical and genetic behaviour]

BACKGROUND

Intracranial aneurysms are abnormal dilations of the cerebral arteries of unknown origin. However, some genes have been linked to their formation, as in the case of NOS3 gene which encodes the endothelial nitric oxide synthase responsible for producing nitric oxide. Several polymorphisms in this gene, in association with a variable number tandem repeat located in intron 4 from eNOS4 gene, can influence the formation of aneurysms. Therefore, the purpose of this study is to determine the genotype frequencies of eNOS3 and eNOS4 genes, and their relationship with intracranial aneurysms.

MATERIAL AND METHODS

A prospective case-control study was performed on 79 cases with ruptured intracranial aneurysm and 93 healthy controls. DNA was obtained from all subjects for the study of the eNOS3 and eNOS4 genes by molecular techniques.

RESULTS

The GG genotype of eNOS3 gene showed the largest number of patients (n=29) with a large aneurysm. While the intracranial aneurysms of medium size were found in a higher percentage (50%) in patients with genotype GT. In terms of patient outcomes, it was observed that those with genotype GG had the highest percentage (43.13%) recovery, compared to genotype GT (27.27%).

CONCLUSIONS

The present study shows that there is a tendency of an association between genotypes of eNOS3 gene with the mean size of the aneurysm, as well as clinical sequelae of the disease in patients with intracranial aneurysms.

Endovascular treatment of bifurcation intracranial aneurysms with the WEB SL/SLS: 6-month clinical and angiographic results

BACKGROUND

The WEB device is a recent intrasaccular flow disruption technique developed for the treatment of wide-necked intracranial aneurysms. To date, a single report on the WEB Single-Layer (SL) treatment of intracranial aneurysms has been published with 1-months' safety results. The aim of this study is to report our experience and 6-month clinical and angiographic follow-up of endovascular treatment of wide-neck aneurysm with the WEB SL.

METHODS

Ten patients with 10 unruptured wide-necked aneurysms were prospectively enrolled in this study. Feasibility, intraoperative and postoperative complications, and outcomes were recorded. Immediate and 6-month clinical and angiographic results were evaluated.

RESULTS

Failure of WEB SL placement occurred in two cases. Eight aneurysms were successfully treated using one WEB SL without additional treatment. Three middle cerebral artery, four anterior communicating artery, and one basilar artery aneurysms were treated. Average dome width was 7.5 mm (range 5.4-10.7 mm), and average neck size was 4.9 mm (range 2.6-6.5 mm). No periprocedural complication was observed, and morbi-mortality at discharge and 6 months was 0.0%. Angiographic follow-up at 6 months demonstrated complete aneurysm occlusion in 2/8 aneurysms, neck remnant in 5/8 aneurysms, and aneurysm remnant in 1/8 aneurysm.

CONCLUSIONS

From this preliminary study, treatment of bifurcation intracranial aneurysms using WEB SL is feasible. WEB SL treatment seems safe at 6 months; however, the rate of neck remnants is not negligible due to compression of the WEB SL. Further technical improvements may be needed in order to ameliorate the occlusion in the WEB SL treatment.

Comparison of Intracranial Aneurysms Treated by 2-D Versus 3-D Coils: A Matched-Pairs Analysis

OBJECTIVE

Knowledge on the influence of 2D and 3D coils to occlude intracranial aneurysms is poor. Therefore, aim of our analysis was to evaluate whether the use of 3-D versus 2-D coils alone may improve the efficacy of endovascular aneurysm treatment.

PATIENTS AND METHODS

We performed a matched pair analysis comparing aneurysms treated by 3-D coils as initial "framing" coils to aneurysms treated exclusively by 2-D coils. Number of coils, implanted coil length/volume, and associated packing density were calculated. Aneurysmal occlusion was assessed and monitored 6 months (DSA; magnetic resonance angiography (MRA)) and 18 months (MRA) after embolization. Periprocedural complications and retreatment rate of each group were analyzed.

RESULTS

Our retrospective analysis revealed 50 pairs. Concerning the 3-D group, number of coils (353 in total, median 7; p = 0.002), implanted coil length (55.69  ± 48.4 cm), implanted coil length per volume (5.92 mm/mm³), and packing density (30 %; p = 0.017) was higher than in the 2-D group (259 in total, median 5 coils; 38.52 ± 43.13 cm; 4.54 mm/mm³; 23 %). Occlusion was not significantly different immediately after treatment but at 6 and 18 months follow-up in favor of 3-D coils. Retreatment was performed in 2 cases of the 3-D group and in 3 cases of the 2-D group and therefore in a similar range (p = 0.564).

CONCLUSION

Initial use of 3-D coils revealed a higher packing density and a higher long-term occlusion. Therefore, we recommend initial use of 3-D coils.

Early Experience with the TransForm™ Occlusion Balloon Catheter: A Single-Center Study

BACKGROUND AND OBJECTIVE

Balloon-assisted coil embolization has become an important adjunct in the endovascular treatment of intracranial aneurysms. The management of broad-necked cerebral aneurysms is technically perplexed due to a variety of factors, which include the difficulty in defining the aneurysm-parent vessel interface angiographically and problems in achieving complete aneurysmal occlusion. This could later predispose to regrowth or recanalization. We sought to determine the safety and efficacy of the TransForm™ occlusion balloon catheter (TOBC) for the coiling of intracranial aneurysms at our institute.

METHODS

A retrospective review was performed to identify TOBC cases between May 1, 2013, and April 30, 2014.

RESULTS

A total of 24 TOBC cases were identified. In 23 cases, the TOBC was used for balloon-remodeled coil embolization, and in 1 case, it was used for vasospasm treatment alone. Out of the total 24 cases in which the TOBC was used, 16 (66.6%) were ruptured aneurysms. Stents were used in 6/23 (26%) cases. In all cases, the balloon could be placed as intended. The inflation and deflation times ranged from 3 to 4 s. No serious complications were noted. In the experience of the authors, the balloon performed the intended role in most cases.

CONCLUSIONS

This series shows that the TOBC is feasible, safe and useful in the treatment of cerebral aneurysms. The balloon was traceable to the intended site and the preparation, inflation and deflation times were short. We believe that the TOBC has effective utility in treating broad-necked and small aneurysms.

Computation of the change in length of a braided device when deployed in realistic vessel models

PURPOSE

An important issue in the deployment of braided stents, such as flow diverters, is the change in length, also known as foreshortening, underwent by the device when is released from the catheter into a blood vessel. The position of the distal end is controlled by the interventionist, but knowing a priori the position of the proximal end of the device is not trivial. In this work, we assess and validate a novel computer method to predict the length that a braided stent will adopt inside a silicon model of an anatomically accurate vessel.

METHODS

Three-dimensional rotational angiography images of aneurysmatic patients were used to generate surface models of the vessels (3D meshes) and then create accurate silicon models from them. A braided stent was deployed into each silicon model to measure its length. The same stents deployed on the silicon models were virtually deployed on the 3D meshes using the method being evaluated.

RESULTS

The method was applied to five stent placements on three different silicon models. The length adopted by the real braided device in the silicon models varies between 15 and 30% from the stent length specified by the manufacturer. The final length predicted by the method was within the estimated error of the measured real stent length.

CONCLUSIONS

The method provides, in a few seconds, the length of a braided stent deployed inside a vessel, showing an accurate estimation of the final length for the cases studied. This technique could provide useful information for planning the intervention and improve endovascular treatment of intracranial aneurysms in the future.

Morphological-Hemodynamic Characteristics of Intracranial Bifurcation Mirror Aneurysms

BACKGROUND

Many morphological and hemodynamic parameters have been proposed as promising aneurysm rupture status discriminators. Besides, a clear dichotomy between sidewall and bifurcation aneurysms was reported. In this study, we strove to evaluate the contribution of many reported morphological and hemodynamic parameters to retrospective rupture status determination in bifurcation aneurysms independent of patients' characteristics.

METHODS

Computational fluid dynamics were performed on 16 patients with bifurcation mirror aneurysms (MANs). Each pair was divided into ruptured and unruptured groups. The morphological and hemodynamic factors were analyzed and compared. Receiver operating characteristics (ROC) analysis was performed, and the area under the ROC curve (AUC) was calculated for all parameters to quantify the predictability of each index and identify the optimal threshold.

RESULTS

Morphological (size, aspect ratio, size ratio, and height-width ratio) and hemodynamic (time-averaged mean wall shear stress [WSSmean], low WSS area [LSA]) parameters reached statistical significance (P < 0.05). Aneurysm irregular shape, oscillatory shear index (OSI), flow stability, inflow concentration, and impingement zone did not achieve significantly statistical differences (P = 0.508, P = 0.319, P = 0.523, P = 0.227, and P = 1.000, respectively). After ROC analysis, only aspect ratio and LSA had excellent AUC values (0.840 and 0.824, respectively). Other key parameters, including size, size ratio, height-width ratio, and WSSmean, had AUC values between 0.7 and 0.8 (0.730, 0.715, 0.703, 0.727, respectively).

CONCLUSIONS

Higher aspect ratio and LSA are good indicators for bifurcation aneurysm rupture. MANs with different rupture status might be a useful disease model in which many factors are balanced to investigate possible features linked to aneurysm rupture.

The supraorbital endoscopic approach for aneurysms

OBJECTIVE

To review our surgical experience in minimally invasive transcranial endoscope-assisted microsurgical treatment of intracranial aneurysms, using the supraorbital keyhole craniotomy.

METHODS

The supraorbital keyhole approach was performed through an eyebrow skin incision in 793 cases for treatment of 989 intracranial aneurysms. Of patients, 474 were operated on after subarachnoid hemorrhage, and 319 were operated on under elective conditions. After lateral frontobasal burr hole trephination, a limited subfrontal craniotomy was created. To achieve adequate intraoperative exposure through the limited approach, endoscopes were used routinely. Surgical outcome was assessed using the modified Rankin scale.

RESULTS

The transcranial endoscope-assisted microneurosurgery technique was used routinely via a supraorbital approach. In 152 operations (19.1%), the endoscope provided important visual information in the vicinity of the aneurysm, revealing subsequent clip repositioning. The results of incidental aneurysms were excellent with a modified Rankin scale score ≤2 in 96.52%. The overall outcome of ruptured aneurysms was good with a modified Rankin scale score ≤2 in 72.2% of patients. There were no approach-related intraoperative or postoperative complications.

CONCLUSIONS

The minimally invasive supraorbital keyhole approach allowed safe surgical treatment of intracranial aneurysms, including after subarachnoid hemorrhage. The markedly improved endoscopic visualization increased the assessment of clip placement with ideal control of surrounding vessels including perforators for identification of incorrect clip position.

microRNAs in Cerebrovascular Disease

Cardiovascular diseases are major causes of morbidity and mortality in developed countries. Cerebrovascular diseases, especially stroke, represent major burden of disability and economy impact. Major advances in primary and secondary prevention and therapy are needed in order to tackle this public health problem. Our better understanding of pathophysiology is essential in order to develop novel diagnostic and therapeutic tools and strategies. microRNAs are a family of important post-transcriptional regulators of gene expression and their involvement in the pathophysiology of cerebrovascular diseases has already been reported. Moreover, microRNAs may represent above-mentioned potential diagnostic and therapeutic tools in clinical practice. Within this chapter, we briefly describe basic epidemiology, aetiology and clinical manifestation of following cerebrovascular diseases: extracranial carotid atherosclerosis, acute stroke, intracranial aneurysms and cerebral arterio-venous malformations. Further, in each chapter, the current knowledge about the involvement of specific microRNAs and their potential use in clinical practice will be summarized. More specifically, within the subchapter "miRNAs in carotid atherosclerosis", general information about miRNA involvement in atherosclerosis will be described (miR-126, miR-17-92, miR-155 and others) with special emphasis put on miRNAs affecting carotid plaque progression and stability (e.g. miR-145, miR-146 or miR-217). In the subchapter "miRNAs in acute stroke", we will provide insight into recent knowledge from animal and human studies concerning miRNA profiling in acute stroke and their expression dynamics in brain tissue and extracellular fluids (roles of, e.g. let-7 family, miR-21, miR-29 family, miR-124, miR-145, miR-181 family, miR-210 and miR-223). Subchapters dealing with "miRNAs and AV malformations" and "miRNAs and intracranial aneurysms" will focus on miR-21, miR-26, miR-29 family and miR-143/145.

Endovascular embolization is applicable for large and giant intracranial aneurysms: experience in one center with long-term angiographic follow-up

BACKGROUND

Endovascular treatment of large and giant intracranial aneurysms and long-term results of angiographic follow-up of these aneurysms treated endovascularly are not known currently.

PURPOSE

To investigate the outcome of endovascular treatment of large and giant aneurysms and the long-term angiographic follow-up results.

MATERIAL AND METHODS

A retrospective analysis of all patients with endovascular treatment of large and giant aneurysms between 1998 and 2009 was performed. There were 90 large or giant aneurysms treated with coiling alone, stent-assisted coiling, covered-stent deployment, or parent artery occlusion (PAO) in 88 patients (female/male, 54/34; age range, 23-92 years; mean age, 56 years).

RESULTS

Immediately after the initial endovascular embolization procedure, complete occlusion was achieved in 56.7%, near complete occlusion in 37.8%, and incomplete occlusion in 5.5%. The total periprocedural complication rate excluding subarachnoid hemorrhage (SAH)-induced vasospasm was 10.2% with a mortality rate of 2.3%. Follow-up angiography was performed in all of the aneurysms with the longest follow-up duration of 131 months. Among 38 aneurysms initially treated with coiling alone and 17 initially treated with stent-assisted coiling, 22 (57.9%) and four (23.5%) recurred, respectively, during follow-up. No recurrence occurred in aneurysms initially treated with covered-stent deployment or PAO. Aneurysm recurrence was predominantly seen in older and female patients, in larger aneurysms, and in aneurysms treated with coiling alone. Twenty-three aneurysms were successfully retreated endovascularly.

CONCLUSION

Endovascular intervention with coiling alone or stent-assisted coiling for large and giant cerebral aneurysms is not very effective, while covered stents are more promising. Better endovascular devices are needed to obtain more secure closure.

[Variability in decision-making for treatment choice of intracranial aneurysms]

OBJECTIVES

To measure the variability in choosing treatment options in different clinical situations involving intracranial aneurysms.

MATERIALS AND METHODS

A questionnaire regarding 25 clinical cases was presented via visual projection, to attendees of the Congrès de la Société française de neurochirurgie et de la Société de langue française de neurochirurgie held in Toulouse from May 9th to May 12th, 2012. The audience (n=59) consisted of 58 neurosurgeons and one neuroradiologist. A minority of them (29.2%) stated that they specialized in vascular neurosurgery. The questionnaire dealt with 25 illustrative clinical cases, in which age, gender, and clinical context were provided along with the corresponding angiographic image of the aneurysm. The questionnaire asked whether the physician would have proposed treatment, and if so, which type of treatment (clip, coil or other). In addition, the physician had to indicate, on a scale of one to ten, the degree of confidence they had in their decision.

RESULTS

For one-third of the cases, there was at least 10% of the respondents who opted for a decision opposite to the one of the majority. For 41.7% of the cases, the proportion of respondents who opted for the clip was not significantly different from the proportion of those who opted for the coil.

CONCLUSION

Even in a relatively homogenous group of physicians, there were significantly diverging opinions regarding the management of cerebral aneurysms. This demonstrates the need for evidence-based data from controlled randomized studies.

Realistic non-Newtonian viscosity modelling highlights hemodynamic differences between intracranial aneurysms with and without surface blebs

Most computational fluid dynamic (CFD) simulations of aneurysm hemodynamics assume constant (Newtonian) viscosity, even though blood demonstrates shear-thinning (non-Newtonian) behavior. We sought to evaluate the effect of this simplifying assumption on hemodynamic forces within cerebral aneurysms, especially in regions of low wall shear stress, which are associated with rupture. CFD analysis was performed for both viscosity models using 3D rotational angiography volumes obtained for 26 sidewall aneurysms (12 with blebs, 12 ruptured), and parametric models incorporating blebs at different locations (inflow/outflow zone). Mean and lowest 5% values of time averaged wall shear stress (TAWSS) computed over the dome were compared using Wilcoxon rank-sum test. Newtonian modeling not only resulted in higher aneurysmal TAWSS, specifically in areas of low flow and blebs, but also showed no difference between aneurysms with or without blebs. In contrast, for non-Newtonian analysis, bleb-bearing aneurysms showed significantly lower 5% TAWSS compared to those without (p=0.005), despite no significant difference in mean dome TAWSS (p=0.32). Non-Newtonian modeling also accentuated the differences in dome TAWSS between ruptured and unruptured aneurysms (p<0.001). Parametric models further confirmed that realistic non-Newtonian viscosity resulted in lower bleb TAWSS and higher focal viscosity, especially when located in the outflow zone. The results show that adopting shear-thinning non-Newtonian blood viscosity in CFD simulations of intracranial aneurysms uncovered hemodynamic differences induced by bleb presence on aneurysmal surfaces, and significantly improved discriminant statistics used in risk stratification. These findings underline the possible implications of using a realistic model of blood viscosity in predictive computational hemodynamics.

Are infundibular dilatations at risk of further transformation? Ten-year progression of a prior documented infundibulum into a saccular aneurysm and rupture: Case report and a review of the literature

Infundibular dilatations (IFDs) are conical, triangular, or funnel-shaped enlargements at the origin of cerebral arteries, and they are primarily located (7-25%) on the posterior communicating artery (PComA). Progression over time into a saccular aneurysm with a risk of rupture of a previously demonstrated IFD has rarely been reported. We report the case of a 60-year-old female who presented 10 years earlier with a subarachnoid hemorrhage caused by a left internal carotid artery aneurysm rupture. At that time, the carotid angiography showed the left internal carotid artery aneurysm and a right posterior communicating artery infundibular dilatation. Neck clipping for the left internal carotid artery aneurysm was performed and the patient was discharged with no neurological deficit. Ten years later, the patient suffered a second fatal subarachnoid hemorrhage; carotid angiography revealed a right posterior communicating artery aneurysm developed from the previously documented infundibular dilatation with a de novo right anterior choroidal artery aneurysm. This case is another proof of the small but growing number of examples of infundibular transformation over time, as well as their risk of progression into saccular aneurysms and subsequent rupture.

Intra-aneurysmal thrombus modification after flow-diversion

Flow diversion has been successfully used to treat large and giant intracranial aneurysms that present with mass effect. We conducted a retrospective review, evaluating the modification of thrombi in this aneurysm type after treatment with the Pipeline Embolization Device (ev3 Endovascular, Plymouth, MN, USA) and the effects of these modifications on symptoms. Eight patients, seven of whom were female, harbored eight partially thrombosed large or giant aneurysms. Five of the eight aneurysms presented with symptomatic mass effect. At 1 year follow-up, complete occlusion occurred in 75% (6/8) of patients. On average, the longest thrombus diameter measured 22.31 mm before treatment and 14.05 mm 1 year afterwards. Seven of the eight thrombi regressed, as did their aneurysms. All six patients with shrunken thrombi had tremendous symptom improvement and became asymptomatic in the following year. The current findings seem to reflect the size variation of the intra-aneurysmal thrombus rather than the size of the aneurysm itself.

Aneurysm Recurrence Volumetry Is More Sensitive than Visual Evaluation of Aneurysm Recurrences

PURPOSE

Considerable inter-observer variability in the visual assessment of aneurysm recurrences limits its use as an outcome parameter evaluating new coil generations. The purpose of this study was to compare visual assessment of aneurysm recurrences and aneurysm recurrence volumetry with an example dataset of HydroSoft coils (HSC) versus bare platinum coils (BPC).

METHODS

For this retrospective study, 3-dimensional time-of-flight magnetic resonance angiography datasets acquired 6 and 12 months after endovascular therapy using BPC only or mainly HSC were analyzed. Aneurysm recurrence volumes were visually rated by two observersas well as quantified by subtraction of the datasets after intensity-based rigid registration.

RESULTS

A total of 297 aneurysms were analyzed (BPC: 169, HSC: 128). Recurrences were detected by aneurysm recurrence volumetry in 9 of 128 (7.0 %) treated with HSC and in 24 of 169 (14.2 %) treated with BPC (odds ratio: 2.39, 95 % confidence interval: 1.05-5.48; P = 0.039). Aneurysm recurrence volumetry revealed an excellent correlation between observers (Cronbach's alpha = 0.93). In contrast, no significant difference in aneurysm recurrence was found for visual assessment (3.9 % in HSC cases and 4.7 % in BPC cases). Recurrences were observed in aneurysms smaller than the sample median in 10 of 33 (30.3 %) by aneurysm recurrence volumetry and in 1 of 13 (7.7 %) by visual assessment.

CONCLUSIONS

Aneurysm recurrences were detected more frequently by aneurysm recurrence volumetry when compared with visual assessment. By using aneurysm recurrence volumetry, differences between treatment groups were detected with higher sensitivity and inter-observer validity probably because of the higher detection rate of recurrences in small aneurysms.

Pitfalls and complications management in the endovascular treatment of aneurysms

This article reviews complications associated with the endovascular management of intracranial aneurysms, focusing on risk factors, avoidance, recognition, and management. Such complications can be devastating. Both neurologic and nonneurologic complications can occur. Several patient and procedure related parameters can increase the incidence of complications. Reduction of complication rates can be achieved by careful patient selection, meticulous planning and preparation for the procedure, anticipating potential complications, and preparing for their management. Tracking outcomes and a robust case conference can further enhance outcomes. Education of the care team and a collaborative environment can foster greater focus on avoidance of complications.

In-hospital outcomes of aneurysmal subarachnoid hemorrhage associated with cocaine use in the USA

Cocaine use is associated with higher mortality in small retrospective studies of brain-injured patients. We aimed to explore in-hospital outcomes in a large population based study of aneurysmal subarachnoid hemorrhage (aSAH) with cocaine use. aSAH patients were identified from the 2007-2010 USA Nationwide Inpatient Sample using International Classification of Disease, Ninth Revision codes. Demographics, comorbidities and surgical procedures were compared between cocaine users and non-users. The primary outcomes were in-hospital mortality and home discharge/self-care. Secondary outcomes were vasospasm treated with angioplasty, hydrocephalus, gastrostomy and tracheostomy. There were 103,876 patients with aSAH. The cocaine group were younger (45.8 ± 9.8 versus 58.4 ± 15.8, p<0.001), predominantly male (53.3% versus 38.5%, p<0.001) and had a higher proportion of black patients (36.9% versus 11.5%, p<0.001). The incidence of seizures was higher among cocaine users (16.2% versus 11.1%, p<0.001). Endovascular coiling of intracranial aneurysms (24% versus 18.5%, p<0.001) was more frequent in cocaine users. The univariate analysis showed higher rates of in-hospital mortality and vasospasm treated with angioplasty, but lower home discharge in the cocaine group. In the multivariate analysis, the cocaine cohort had higher in-hospital mortality (odds ratio [OR] 1.43, 95% confidence interval [CI] 1.27-1.61, p<0.001) and lower home discharge rates (OR 0.79, 95% CI 0.69-0.87, p<0.001) after adjusting for confounders. Rates of vasospasm treated with angioplasty however were similar between the two groups. Cocaine use was found to be independently associated with poor outcomes, particularly higher mortality and lower home discharge rates. Cocaine use however, was not associated with vasospasm that required treatment with angioplasty. Prospective confirmation is warranted.

Cognitive function, depression, anxiety and quality of life in Chinese patients with untreated unruptured intracranial aneurysms

Detected unruptured intracranial aneurysms (UIA) are becoming more common with the increased utilization of CT angiography, MR angiography and digital subtraction angiography. A proportion of patients with UIA remain untreated. We investigated to assess cognitive function, depression, anxiety and quality of life (QoL) in Chinese patients with untreated UIA. Thirty one Chinese patients with untreated UIA and 25 healthy controls were identified and matched for variables including age, sex, and living area. Cognitive function was evaluated with the Montreal Cognitive Assessment (MoCA). Depression, anxiety and QoL were screened with the Self-Rating Depression Scale, Self-Rating Anxiety Scale, and Short Form-36, respectively. Non-parametric tests were used for comparisons between groups. No patient had cognitive dysfunction at 1 month or 1 year after detection of UIA. However, a significant decrease of overall MoCA subscores was found in 30 (97%) of 31 patients 5 years after UIA discovery, suggestive of mild cognitive impairment. A significant decrease in depression and anxiety was found in patients over time. QoL in patients was reduced most prominently in psychosocial function and social activities 1 year after detection of UIA, but these improved to within normal limits at the end of the follow-up period. For Chinese patients with untreated UIA, depression, anxiety and reduced QoL may be short-term complications. Mild cognitive impairment may be a long-term complication.

A Self-expanding Nitinol Stent (Enterprise) for the Treatment of Wide-necked Intracranial Aneurysms: Angiographic and Clinical Results in 40 Aneurysms

Objective

Self-expanding stents are increasingly used for the treatment of complex intracranial aneurysms. The purpose of this study was to evaluate the usefulness and safety of a self-expanding nitinol stent (Enterprise) in the treatment of wide-necked intracranial aneurysms.

Methods

This was a retrospective study of 39 patients with 40 wide-necked intracranial aneurysms who were enrolled in a single-center registry of patients treated with the Enterprise between June 2009 and December 2011. Thirty patients were asymptomatic, four had cerebrovascular accident sequelae, and five had suffered subarachnoid hemorrhage. One aneurysm had reopened after prior coil embolization, while 39 had not been treated. Clinical charts, procedural data, and angiographic results, including both immediate post-procedural angiograms and follow-up imaging, were reviewed.

Results

The mean neck size of the aneurysms was 5.58 mm (range 3-15.1 mm). Embolization was successful in all patients. There were five procedure-related events. There were no fatalities, but one procedure-related morbidity was noted. The immediate angiographic results included eight complete occlusions (20%), six remnant necks (15%), and 26 remnant sacs (65%). At angiographic follow-up (mean: 11.3 months), out of 18 of the aneurysms treated with stent-assisted coiling, there were 13 (72.2%) complete occlusions, four (22.2%) remnant necks, and one recanalization (5.6%).

Conclusion

Stent-assisted coiling using the Enterprise is effective for the treatment of wide-necked intracranial aneurysms. Further angiographic and clinical follow-up investigation will be needed for evaluation of the long-term outcomes.