Predictors of Rehemorrhage After Treatment of Ruptured Intracranial Aneurysms

Open Microsurgical Cerebral Aneurysm Treatment After Failed Endovascular Therapy: An Evaluation of Aneurysm Treatment Frequencies in All Neurovascular Centers Across Austria and the Czech Republic Over 20 Years

BACKGROUND AND OBJECTIVES

Endovascular treatment of cerebral aneurysms has tremendously advanced over the past decades. Nevertheless, aneurysm residual and recurrence remain challenges after embolization. The objective of this study was to elucidate the portion of embolized aneurysms requiring open surgery and evaluate whether newer endovascular treatments have changed the need for open surgery after failed embolization.

METHODS

All 15 cerebrovascular centers in Austria and the Czech Republic provided overall aneurysm treatment frequency data and retrospectively reviewed consecutive cerebral aneurysms treated with open surgical treatment after failure of embolization from 2000 to 2022. All endovascular modalities were included.

RESULTS

On average, 1362 aneurysms were treated annually in the 2 countries. The incidence increased from 0.006% in 2005 to 0.008% in 2020 in the overall population. Open surgery after failed endovascular intervention was necessary in 128 aneurysms (0.8%), a proportion that remained constant over time. Subarachnoid hemorrhage was the initial presentation in 70.3% of aneurysms. The most common location was the anterior communicating artery region (40.6%), followed by the middle cerebral artery (25.0%). The median diameter was 6 mm (2-32). Initial endovascular treatment included coiling (107 aneurysms), balloon-assist (10), stent-assist (4), intrasaccular device (3), flow diversion (2), and others (2). Complete occlusion after initial embolization was recorded in 40.6%. Seventy-one percent of aneurysms were operated within 3 years after embolization. In 7%, the indication for surgery was (re-)rupture and, in 88.3%, reperfusion. Device removal was performed in 16.4%. Symptomatic intraoperative and postoperative complications occurred in 10.2%. Complete aneurysm occlusion after open surgery was achieved in 94%.

CONCLUSION

Open surgery remains a rare indication for cerebral aneurysms after failed endovascular embolization even in the age of novel endovascular technology, such as flow diverters and intrasaccular devices. Regardless, it is mostly performed for ruptured aneurysms initially treated with primary coiling that are in the anterior circulation.

Surgical Treatment Strategies for Residual or Recurrent Intracranial Aneurysms Following Endovascular Embolization

OBJECTIVE

To explore how to effectively manage the residual or recurrent intracranial aneurysms after embolization.

METHODS

The authors retrospectively reviewed our experience of endovascular interventional therapy, surgical clipping, and cerebrovascular bypass surgery in the treatment of residual or recurrent aneurysms after embolization at the authors' institution from 2018 to 2022.

RESULTS

The Glasgow Outcome Scale of 28 patients after the procedure and at discharge showed that 24 recovered well, 3 had severe disability, and 1 died. During the 24-month follow-up, 26 had a good recovery, 1 suffered from disability, and 1 died. Two cases of aneurysm recurrence were detected, and both were treated through endovascular therapy. Among them, 1 case underwent a repeat endovascular embolization, and 1 case was switched to surgical clipping. No residual aneurysms were observed in the remaining patients who underwent bypass surgery, and their bypass grafts were all patent.

CONCLUSION

Based on the clinical status of patients, aneurysmal characteristics, surgical risk, and possibility of rerupture of aneurysms, an individualized strategy was proposed for residual or recurrent aneurysms after embolization. The use of endovascular interventional therapy or surgical clipping can be safely and effectively managed, and cerebrovascular bypass surgery can effectively manage complex aneurysms.

Flow Diverter Combined with Coil Embolization for Acutely Ruptured Intracranial Aneurysms: A Single Center Experience

BACKGROUND

Extensive research has confirmed the safety and effectiveness of flow diverters in the treatment of unruptured intracranial aneurysms. However, their use in cases of acute rupture remains a subject of debate.

METHODS

This study was conducted as a single-center retrospective investigation from January 2018 to January 2022 and included patients with acutely ruptured intracranial aneurysms (within three days of rupture) who were treated using the Pipeline Embolization Device with adjunctive coil embolization. Patient demographics, operative procedures, and outcomes were analyzed. Antiplatelet therapy included intra-arterial tirofiban and postoperative dual therapy with clopidogrel and aspirin.

RESULTS

A total of 21 patients (5 males, 16 females) diagnosed with acutely ruptured intracranial aneurysms were included in this study. The aneurysm types included 7 blood blister-like aneurysms (30.0%), 3 dissecting (14.3%), and 1 fusiform aneurysm (4.8%). Perioperative complications occurred in 2 patients (9.5%), and both cases involved thrombogenesis. Nineteen patients completed digital subtraction angiography during follow-up, with an average follow-up time of 8.7 months (5 - 18 months). Results showed a complete embolization rate of 94.7% (18/19), with a partial aneurysm still present in 1 patient. A total of 90.4% (19/21) of patients had a favorable prognosis (modified Rankin Scale score = 0 - 2).

CONCLUSIONS

The Pipeline Embolization Device with adjunctive coil embolization proved to be a viable option for managing acutely ruptured intracranial aneurysms, notwithstanding the potential for ischemic complications.

Kissing Aneurysms of the Anterior Communicating Artery Treated With Surgical Clipping: A Case Report and Literature Review

Intracranial "kissing" aneurysms are rare vascular conditions described as two anatomically adjacent aneurysms originating from either the same or different arteries, with their walls pressed together. Two-dimensional angiography was formerly considered the gold standard for diagnosis, with the three-dimensional rotational type now offering more insightful details about vascular discrepancies. The treatment of anterior communicating artery (AcoA) "kissing" aneurysms poses significant challenges, with surgical clipping proving difficult due to their deep midline location or the bilateral anterograde arterial supply. However, advancements in endovascular coil embolization, such as dual-volume reconstruction, can assist in diagnosis. This study presents the case of a 50-year-old patient who was diagnosed with "kissing" aneurysms of the AcoA. The patient underwent surgical clipping and showed no pathological follow-up findings. The surgical intervention often provides a more direct and effective approach. This case contributes to the body of knowledge surrounding the management of this complex disease.

Acute Coiling With Delayed Flow Diversion for Posterior Communicating Segment Internal Carotid Artery Aneurysms: A Multicenter Case Series

BACKGROUND AND OBJECTIVES

In ruptured posterior communicating artery (PcomA) aneurysms, the protection of the aneurysm dome alone with initial subtotal coiling decreases the risk of rerupture in the acute setting but does not provide durable/definitive long-term protection against delayed rupture. Delayed flow diverter (FD) placement can be a potential alternative to definitively secure these aneurysms without increasing the risk of complications and PComA occlusion. We analyzed PComA aneurysms treated with a planned delayed FD after primary coiling and assess radiographic and clinical outcomes.

METHODS

We performed a retrospective study of prospectively collected data for intracranial aneurysms treated with planned FD at 2 institutions from 2013 to 2022. PComA aneurysms that underwent primary coiling and delayed FD placement were included for analysis.

RESULTS

There were 29 PComA aneurysms identified that were included in the analysis. Patients were mostly female (79.3%), with a median age of 60 years. The mean aneurysm maximum diameter was 7.2 mm ± (5.3). Immediate Raymond-Roy occlusion grade after primary coiling was I in 48.3%, II in 41.4%, and III in 10.3% of aneurysms. The median time from initial coiling to planned delayed FD placement was 6.3 months (3.2-18.6). A total of 21 (72.4%) aneurysms underwent follow-up radiological imaging. Complete and near-complete occlusion status was achieved in 76.2% of the evaluated aneurysms. There were no retreatments and no evidence of delayed aneurysm rupture. One case (3.5%) presented thromboembolic complications and 1 (3.5%) intracranial hemorrhagic complication after FD placement, which was associated with mortality. Most patients (90.5%) had a modified Rankin scale of ≤2 on the last follow-up.

CONCLUSION

Primary coiling with planned staged FD placement is effective for treating ruptured PComA aneurysms with high occlusion rates and low complications.

Degrees of macrophage-facilitated healing in aneurysm occlusion devices

Insufficient healing of aneurysms following treatment with vascular occlusion devices put patients at severe risk of fatal rupture. Therefore, promoting healing and not just occlusion is vital to enhance aneurysm healing. Following occlusion device implantation, healing is primarily orchestrated by macrophage immune cells, ending with fibroblasts depositing collagen to stabilize the aneurysm neck and dome, preventing rupture. Several modified occlusion devices are available currently on-market. Previous in vivo work demonstrated that modifications of occlusion devices with a shape memory polymer foam had enhanced aneurysm healing outcomes. To better understand cellular response to occlusion devices and improve aneurysm occlusion device design variables, we developed an in vitro assay to isolate prominent interactions between devices and key healing players: macrophages and fibroblasts. We used THP-1 monocyte derived macrophages and human dermal fibroblasts in our cell culture models. Macrophages were allowed device contact with on-market competitor aneurysm occlusion devices for up to 96 h, to allow for any spontaneous device-driven macrophage activation. Macrophage secreted factors were captured in the culture media, in response to device-specific activation. Fibroblasts were then exposed to device-conditioned macrophage media (with secreted factors alone), to determine if there were any device-induced changes in collagen secretion. Our in vitro studies were designed to test the direct effect of devices on macrophage activation, and the indirect effect of devices on collagen secretion by fibroblasts to promote aneurysm healing and stabilization. Over 96 h, macrophages displayed significant migration toward and interaction with all tested devices. As compared to other devices, shape memory polymer foams (SMM, Shape Memory Medical) induced significant changes in gene expression indicating a shift toward an anti-inflammatory pro-healing M2-like phenotype. Similarly, macrophages in contact with SMM devices secreted more vascular endothelial growth factor (VEGF) compared with other devices. Macrophage conditioned media from SMM-contacted macrophages actively promoted fibroblast secretion of collagen, comparable to amounts observed with exogenous stimulation via VEGF supplementation. Our data indicate that SMM devices may promote good aneurysm healing outcomes, because collagen production is an essential step to ultimately stabilize an aneurysm.

Long-term outcomes of surgical clipping of saccular middle cerebral artery aneurysms: a consecutive series of 92 patients

Despite advances in endovascular treatment, microsurgical clipping of middle cerebral artery (MCA) aneurysms remains appropriate. We review the high occlusion rate and treatment durability seen with surgical clipping of MCA aneurysms. We retrospectively reviewed patients who underwent microsurgical clipping of saccular MCA aneurysms by a single surgeon. Outcomes included aneurysm occlusion rate and durability, modified Rankin scale (mRS), and postoperative neurological morbidities. Ninety-two patients with 92 saccular MCA aneurysms were included, 50% of which were ruptured aneurysms. The mean follow-up period was 59 months. Complete aneurysm occlusion was achieved in all except one patient (99%) with near-complete occlusion. MCA aneurysm clipping was durable, with only one patient (1%) requiring retreatment after 4 years due to regrowth. Of the cohort, 79.3% achieved mRS 0-2 at last follow-up, including all with unruptured aneurysms. Poor outcome at discharge was associated with age > 65 (p = .03), postoperative neurological morbidities (p = .006), and aneurysm rupture (p < .001). Older age remained the single correlate for poor long-term outcome (p = .04). For ruptured aneurysms, predictors of poor long-term outcome included hemiparesis on presentation (p = .017), clinical vasospasm requiring treatment (p = .026), and infarction related to vasospasm (p = .041). Older age (p = .046) and complex anatomy (p = .036) were predictors of new postoperative neurological morbidities in the unruptured group. MCA aneurysm clipping is safe, durable, and should be considered first-line treatment for patients with saccular MCA aneurysms, especially in centers with abundant surgical experience.

Comparative analysis of long term effectiveness of Neuroform Atlas stent versus low profile visualized intraluminal stent/Woven EndoBridge devices in treatment of wide necked intracranial aneurysms

BACKGROUND

We compared the outcomes of wide necked aneurysms (WNA) treated with the Neuroform Atlas with those treated with the low profile visualized intraluminal stent (LVIS) or the Woven EndoBridge (WEB).

METHODS

Objective, prospectively collected, core laboratory adjudicated data from published trials for the Neuroform Atlas, LVIS, and WEB devices were reviewed. ATLAS (Safety and Effectiveness of the Treatment of Wide Neck, Saccular Intracranial Aneurysms With the Neuroform Atlas Stent System) study patients were included if they met other studies' inclusion criteria. Outcomes included (1) primary effectiveness (complete aneurysmal occlusion without retreatment/>50% parent vessel stenosis), (2) primary safety, (3) complete aneurysmal occlusion, and (4) retreatment rates (outcomes evaluated at the 12 month follow-up). Matching adjusted indirect comparison analysis was used to compare outcomes.

RESULTS

Analytical samples included 141 ATLAS subjects meeting WEB-IT (Woven EndoBridge Intrasaccular Therapy Study) criteria (ATLAS/WEB-IT) and 241 meeting LVIS (Pivotal Study of the Low Profile Visualized Intraluminal Support) criteria (ATLAS/LVIS). ATLAS/WEB-IT exhibited significantly higher rates of primary effectiveness and complete occlusion versus WEB (86.6% vs 53.9 %, P<0.0001, and 90.3% vs 53.9%, P<0.0001, respectively). For LVIS, there was no significant differences in primary effectiveness rates between ATLAS and LVIS (84.2% vs 77.7%, respectively, P=0.12). However, ATLAS/LVIS had a significantly higher proportion of patients achieving complete occlusion than LVIS (88.1 vs 79.1, P=0.03). Retreatment rates and primary safety outcomes were not significantly different (P>0.05) for the Atlas versus other devices except for a lower retreatment rate for ATLAS/WEB-IT versus WEB-IT (2.4% vs 9.8%, P=0.01).

CONCLUSION

The Neuroform Atlas provided higher occlusion rates and similar retreatment rates in comparable datasets compared with LVIS and WEB devices when treating WNA.

A shift from open to endovascular repair in the treatment of ruptured middle cerebral artery aneurysms: a single institution experience

PURPOSE

Middle cerebral aneurysms were underrepresented in the two largest trials (BRAT and ISAT) for the treatment of ruptured intracranial aneurysms. Recent institutional series addressing the choice between endovascular or open repair for this subset of aneurysms are few and have not yielded a definitive conclusion. We compare clinical outcomes of patients presenting with acute subarachnoid hemorrhage from ruptured middle cerebral artery aneurysms undergoing either open or endovascular repair.

METHODS

We conducted a retrospective review of 138 consecutive patients with ruptured middle cerebral artery aneurysms admitted into our institution from January 2008 to March 2019 to compare endovascular and open surgical outcomes.

RESULTS

Of the ruptured middle cerebral artery aneurysms, 57 underwent endovascular repair while 81 were treated with open surgery. Over the study period, there was a notable shift in practice toward more frequent endovascular treatment of ruptured MCA aneurysms (31% in 2008 vs. 91% in 2018). At discharge (49.1% vs 29.6%; p = .002) and at 6 months (84.3% vs 58.6%; p = 0.003), patients who underwent endovascular repair had a higher proportion of patients with good clinical outcomes (mRS 0-2) compared to those undergoing open surgery. Long-term follow-up data (endovascular 54.9 ± 37.9 months vs clipping 18.6 ± 13.4 months) showed no difference in rebleeding (1.8% vs 3.7%, p = 0.642) and retreatment (5.3% vs 3.7%, p = 0.691) in both groups.

CONCLUSION

Our series suggests equipoise in the treatment of ruptured middle cerebral artery aneurysms and demonstrates endovascular repair as a potentially feasible treatment strategy. Future randomized trials could clarify the roles of these treatment modalities.

A comparison of treating physician versus independent core lab assessments of post-aneurysm treatment imaging outcomes: an analysis of prospectively collected data from a randomized trial

OBJECTIVE

Aneurysm occlusion has been used as surrogate marker of aneurysm treatment efficacy. Aneurysm occlusion scales are used to evaluate the outcome of endovascular aneurysm treatment and to monitor recurrence. These scales, however, require subjective interpretation of imaging data, which can reduce the utility and reliability of these scales and the validity of clinical studies regarding aneurysm occlusion rates. Use of a core lab with independent blinded reviewers has been implemented to enhance the validity of occlusion rate assessments in clinical trials. The degree of agreement between core labs and treating physicians has not been well studied with prospectively collected data.

METHODS

In this study, the authors analyzed data from the Hydrogel Endovascular Aneurysm Treatment (HEAT) trial to assess the interrater agreement between the treating physician and the blinded core lab. The HEAT trial included 600 patients across 46 sites with intracranial aneurysms treated with coiling. The treating site and the core lab independently reviewed immediate postoperative and follow-up imaging (3-12 and 18-24 months, respectively) using the Raymond-Roy occlusion classification (RROC) scale, Meyer scale, and recanalization survey. A post hoc analysis was performed to calculate interrater reliability using Cohen's kappa. Further analysis was performed to assess whether degree of agreement varied on the basis of various factors, including scale used, timing of imaging, size of the aneurysm, imaging modality, location of the aneurysm, dome-to-neck ratio, and rupture status.

RESULTS

Minimal interrater agreement was noted between the core lab reviewers and the treating physicians for assessing aneurysm occlusion using the RROC grading scale (k = 0.39, 95% CI 0.38-0.40) and Meyer scale (k = 0.23, 95% CI 0.14-0.38). The degree of agreement between groups was slightly better but still weak for assessing recanalization (k = 0.45, 95% CI 0.38-0.52). Factors that significantly improved degree of agreement were scales with fewer variables, greater time to follow-up, imaging modality (digital subtraction angiography), and wide-neck aneurysms.

CONCLUSIONS

Assessment of aneurysm treatment outcome with commonly used aneurysm occlusion scales suffers from risk of poor interrater agreement. This supports the use of independent core labs for validation of outcome data to minimize reporting bias. Use of outcome tools with fewer point categories is likely to provide better interrater reliability. Therefore, the outcome assessment tools are ideal for clinical outcome assessment provided that they are sensitive enough to detect a clinically significant change.

2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage: A Guideline From the American Heart Association/American Stroke Association

AIM

The "2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage" replaces the 2012 "Guidelines for the Management of Aneurysmal Subarachnoid Hemorrhage." The 2023 guideline is intended to provide patient-centric recommendations for clinicians to prevent, diagnose, and manage patients with aneurysmal subarachnoid hemorrhage.

METHODS

A comprehensive search for literature published since the 2012 guideline, derived from research principally involving human subjects, published in English, and indexed in MEDLINE, PubMed, Cochrane Library, and other selected databases relevant to this guideline, was conducted between March 2022 and June 2022. In addition, the guideline writing group reviewed documents on related subject matter previously published by the American Heart Association. Newer studies published between July 2022 and November 2022 that affected recommendation content, Class of Recommendation, or Level of Evidence were included if appropriate. Structure: Aneurysmal subarachnoid hemorrhage is a significant global public health threat and a severely morbid and often deadly condition. The 2023 aneurysmal subarachnoid hemorrhage guideline provides recommendations based on current evidence for the treatment of these patients. The recommendations present an evidence-based approach to preventing, diagnosing, and managing patients with aneurysmal subarachnoid hemorrhage, with the intent to improve quality of care and align with patients' and their families' and caregivers' interests. Many recommendations from the previous aneurysmal subarachnoid hemorrhage guidelines have been updated with new evidence, and new recommendations have been created when supported by published data.

Impact of aneurysm diameter, angulation, and device sizing on complete occlusion rates using the woven endobridge (WEB) device: Single center United States experience

BACKGROUND

The Woven EndoBridge device is a novel treatment option for wide-necked bifurcation intracranial aneurysms (WNBA). While this device has had good results, there remains a subset of WNBA that fail this treatment. The main objective of this study is to identify risk factors that are associated with incomplete occlusion of WEB treated aneurysms at short-term follow up.

METHODS

This was a retrospective study of 31 patients with intracranial aneurysms who were treated with WEB at a single institution in the USA in 2019-2021. Data was collected via chart review on patient demographics, aneurysm characteristics, procedural details, and occlusion status at six months follow up. Bivariate analyses were performed comparing completely occluded aneurysms with neck remnants and residual aneurysms.

RESULTS

16 (52%) had completely occluded aneurysms while 11 (35%) patients had a neck remnant, and 4 (13%) patients had a residual aneurysm at follow up. Patients with neck remnants and residual aneurysms had aneurysms with a larger diameter. A large aneurysm diameter is an independent risk factor for incomplete occlusion (OR 4.23 95% CI 1.08-16.53 P value = 0.038). Patients with residual aneurysms had an average difference between the aneurysm width and WEB diameter of -0.08mm compared to 1.2 mm in patients with occluded aneurysms. 75% of patients with a residual aneurysm presented with a ruptured aneurysm. Lastly, more patients with a residual aneurysm had an immediate angiographic outcome of incomplete occlusion.

CONCLUSION

Larger aneurysms are at risk for incomplete occlusion status post WEB treatment. Larger, ruptured aneurysms with minimal difference in aneurysm and WEB diameter that fail to occlude immediately post-treatment are more likely to present as residual aneurysms at short-term follow up.

Endovascular and Medical Management of Unruptured Intracranial Aneurysms

Unruptured intracranial aneurysms are often discovered incidentally on noninvasive imaging. As use of noninvasive imaging has increased, our understanding of the presumed prevalence of intracranial aneurysms in adults has increased. Incidentally found aneurysms are often asymptomatic; however, they can rarely rupture and cause life-threatening illness. Elective treatment of intracranial aneurysms carries risks which need to be considered along with patient-specific factors (e.g., anatomy, medical comorbidities, personal preferences). In this article, we review the natural history, risk factors for cerebral aneurysm formation and rupture, evidence for medical management, and the safety profile and efficacy of available endovascular treatment options.

Study and modeling of the thrombosis of small cerebral aneurysms, with and without flow diverter, by the lattice Boltzmann method

BACKGROUND AND OBJECTIVE

Small cerebral aneurysms are currently commonly treated non-invasively by flow diverter device. These stents lead to thrombotic occlusion of the aneurysm soon after their placement. The purpose of this work is to model clotting into intracranial aneurysms with and without stents, using a non-Newtonian of blood behavior, and to investigate the importance of stent to generate desired thrombus in intracranial aneurysms.

METHOD

The description of blood flow is made by the Boltzmann lattice equations, while thrombosis is modeled by the "fluid age" model. The lattice Boltzmann method is a computational technique for simulating fluid dynamics. The method is based on a mesoscopic approach, where the fluid is represented by a set of particles that move and interact on a grid. The model for blood coagulation is described by lattice Boltzmann Method, and it doesn't take into account the complicated coagulation pathway, this main idea is developed using the model of residence time of blood: all fluid in the domain is assumed to be capable of clotting, given enough time. The fluid age is measured by a passive scalar using a transport equation, and the node coagulates if the fluid age increases enough. Three small aneurysms of different sizes and shapes with three stents of various porosities were used to test the ability of the model to predict thrombosis. The "occlusion rate" parameter is used to assess the effectiveness of the flow diverter device.

RESULTS

For the large aspect ratio factor, the occlusion is: 91% for flow diverter devise with seven struts. For medium aspect ratio, a rate of 80% is achieved. An occlusion rate of slightly more than 30% is obtained for very small aneurysms with low aspect ratio. The Newtonian model underestimates the volume of thrombosis generated. The difference in the prediction of the thrombosis volume between the Newtonian and no-Newtonian Carreau-Yasuda models is approximately 10%.

CONCLUSION

The occlusion rate is proportional to the aspect ratio form factor. For the large and medium aspect ratio factors, the occlusion is satisfactory. Concerning very small aneurysms with low aspect ratio, aneurysm occlusion is low. This rate can be improved to almost complete occlusion if the flow diverter device is doubled. The generality of the model suggests its extensibility toward any other type of thrombosis (stenosis, thrombosis in aortic aneurysms).

Risk of intracranial aneurysm recurrence after microsurgical clipping based on 3D digital subtraction angiography

OBJECTIVE

Current knowledge of recurrence rates after intracranial aneurysm (IA) surgery relies on 2D digital subtraction angiography (DSA), which fails to detect more than 75% of small aneurysm remnants. Accordingly, the discrimination between recurrence and growth of a remnant remains challenging, and actual assessment of recurrence risk of clipped IAs could be inaccurate. The authors report, for the first time, 3D-DSA-based long-term durability and risk factor data of IA recurrence and remnant growth after microsurgical clipping.

METHODS

Prospectively collected data for 305 patients, with a total of 329 clipped IAs that underwent baseline 3D-DSA, were evaluated. The incidence of recurrent IA was described by Kaplan-Meier curves. Risk factors for IA recurrence were analyzed by multivariable Cox proportional hazards and logistic regression models.

RESULTS

The overall observed proportion of IA recurrence after clipping was 2.7% (9 of 329 IAs) at a mean follow-up of 46 months (0.7% per year). While completely obliterated IAs did not recur during follow-up, incompletely clipped aneurysms (76 of 329) demonstrated remnant growth in 11.8% (3.4% per year). Young age and large initial IA size significantly increased the risk of IA recurrence.

CONCLUSIONS

The findings support those in previous studies that hypothesized that completely clipped IAs have an extremely low risk of recurrence. Conversely, the results highlight the significant risk posed by incompletely clipped IAs. Young patients with initial large IAs and incomplete obliteration have an especially high risk for IA recurrence and therefore should be monitored more closely.

Single-Energy Metal Artifact Reduction (SEMAR) in Ultra-High-Resolution CT Angiography of Patients with Intracranial Implants

PURPOSE

To evaluate the effects of single-energy metal artifact reduction (SEMAR) on image quality of ultra-high-resolution CT-angiography (UHR-CTA) with intracranial implants after aneurysm treatment.

METHODS

Image quality of standard and SEMAR-reconstructed UHR-CT-angiography images of 54 patients who underwent coiling or clipping was retrospectively evaluated. Image noise (i.e., index for metal-artifact strength) was analyzed in close proximity to and more distally from the metal implant. Frequencies and intensities of metal artifacts were additionally measured and intensity-differences between both reconstructions were compared in different frequencies and distances. Qualitative analysis was performed by two radiologists using a four-point Likert-scale. All measured results from both quantitative and qualitative analysis were then compared between coils and clips.

RESULTS

Metal artifact index (MAI) and the intensity of coil-artifacts were significantly lower in SEMAR than in standard CTA in close vicinity to and more distally from the coil-package (p < 0.001, each). MAI and the intensity of clip-artifacts were significantly lower in close vicinity (p = 0.036; p < 0.001, respectively) and more distally from the clip (p = 0.007; p < 0.001, respectively). In patients with coils, SEMAR was significantly superior in all qualitative categories to standard images (p < 0.001), whereas in patients with clips, only artifacts were significantly less (p < 0.05) for SEMAR.

CONCLUSION

SEMAR significantly reduces metal artifacts in UHR-CT-angiography images with intracranial implants and improves image quality and diagnostic confidence. SEMAR effects were strongest in patients with coils, whereas the effects were minor in patients with titanium-clips due to the absent of or minimal artifacts.

Radiological follow-up of endovascularly treated intracranial aneurysms: a survey of current practice in the UK and Ireland

PURPOSE

Due to the risk of intracranial aneurysm (IA) recurrence and the potential requirement for re-treatment following endovascular treatment (EVT), radiological follow-up of these aneurysms is necessary. There is little evidence to guide the duration and frequency of this follow-up. The aim of this study was to establish the current practice in neurosurgical units in the UK and Ireland.

METHODS

A survey was designed with input from interventional neuroradiologists and neurosurgeons. Neurovascular consultants in each of the 30 neurosurgical units providing a neurovascular service in the UK and Ireland were contacted and asked to respond to questions regarding the follow-up practice for IA treated with EVT in their department.

RESULTS

Responses were obtained from 28/30 (94%) of departments. There was evidence of wide variations in the duration and frequency of follow-up, with a minimum follow-up duration for ruptured IA that varied from 18 months in 5/28 (18%) units to 5 years in 11/28 (39%) of units. Young patient age, previous subarachnoid haemorrhage and incomplete IA occlusion were cited as factors that would prompt more intensive surveillance, although larger and broad-necked IA were not followed-up more closely in the majority of departments.

CONCLUSIONS

There is a wide variation in the radiological follow-up of IA treated with EVT in the UK and Ireland. Further standardisation of this aspect of patient care is likely to be beneficial, but further evidence on the behaviour of IA following EVT is required in order to inform this process.

Comparison of staged-stent and stent-assisted coiling technique for ruptured saccular wide-necked intracranial aneurysms: Safety and efficacy based on a propensity score-matched cohort study

Background

Application of stent-assisted coiling and FD in acute phase of ruptured wide-necked aneurysms is relatively contraindicated due to the potential risk of ischemic and hemorrhagic complications. Scheduled stenting after initial coiling has emerged as an alternative paradigm for ruptured wide-necked aneurysms. The objective of this study is to evaluate the safety and efficacy of a strategy of staged stent-assisted coiling in acutely ruptured saccular wide-necked intracranial aneurysms compared with conventional early stent-assisted coiling strategy via propensity score matching in a high-volume center.

Methods

A retrospective review of patients with acutely ruptured saccular wide-necked intracranial aneurysms who underwent staged stent-assisted coiling or conventional stent-assisted coiling from November 2014 to November 2019 was performed. Perioperative procedure-related complications and clinical and angiographic follow-up outcomes were compared.

Results

A total of 69 patients with staged stent-assisted coiling and 138 patients with conventional stent-assisted coiling were enrolled after 1:2 propensity score matching. The median interval time between previous coiling and later stenting was 4.0 weeks (range 3.5-7.5 weeks). No rebleeding occurred during the intervals. The rate of immediate complete occlusion was lower with initial coiling before scheduled stenting than with conventional stent-assisted coiling (21.7 vs. 60.9%), whereas comparable results were observed at follow-up (82.5 vs. 72.9%; p = 0.357). The clinical follow-up outcomes, overall procedure-related complications and procedure-related mortality between the two groups demonstrated no significant differences (P = 0.232, P = 0.089, P = 0.537, respectively). Multivariate analysis showed that modified Fisher grades (OR = 2.120, P = 0.041) were independent predictors for overall procedure-related complications and no significant predictors for hemorrhagic and ischemic complications.

Conclusions

Staged stent-assisted coiling is a safe and effective treatment strategy for acutely ruptured saccular wide-necked intracranial aneurysms, with comparable complete occlusion rates, recurrence rates at follow-up and overall procedure-related complication rates compared with conventional stent-assisted coiling strategy. Staged stent-assisted coiling could be an alternative treatment option for selected ruptured intracranial aneurysms in the future.

WEB Treatment of Ruptured Intracranial Aneurysms: Long-Term Follow-up of a Single-Center Cohort of 100 Patients

BACKGROUND AND PURPOSE

The Woven EndoBridge device (WEB) was introduced for the intrasaccular treatment of wide-neck aneurysms without the need for adjunctive devices. We used the WEB as a primary treatment for 100 ruptured aneurysms regardless of neck size or location. In this study, we present the long-term follow-up of 78 surviving patients.

MATERIALS AND METHODS

Between February 2015 and April 2017, one hundred ruptured aneurysms were treated with the WEB. For surviving patients, angiographic and clinical follow-up was scheduled at 3 months, and 3T MRA and clinical follow-up, at 6, 12, 36, and 60 months. Of 100 patients, 18 died during hospital admission, and in 4, the ruptured aneurysm was additionally treated. The remaining 78 patients had a mean follow-up of 51 months (median, 52 months; range, 5-84 months). There were 57 women and 21 men, with a mean age of 58.5 years (median, 59 years; range, 24-80 years). Of 78 aneurysms with long-term follow-up, 52 (66%) had a wide neck.

RESULTS

Of 78 ruptured aneurysms, 56 (72%) remained completely occluded and 17 (22%) had a stable small neck remnant. Five of 78 aneurysms (6%; 95% CI, 2.4%-14.5%) reopened during follow-up and were additionally treated. There were no rebleeds during follow-up.

CONCLUSIONS

Treatment of ruptured aneurysms with the WEB was safe and effective and has long-term results comparable with those of simple coiling of small-neck aneurysms. The WEB proved to be a valuable alternative to coils for both wide- and small-neck ruptured aneurysms without the need for stents, balloons, or antiplatelet therapy.

[Microsurgical and endovascular treatment of residual and recurrent cerebral aneurysms]

Cerebral aneurysms are characterized by high risk of adverse outcome due to severe intracranial hemorrhages and their consequences. Aneurysm remnants after incomplete exclusion can cause hemorrhage. Filling of these fragments immediately after surgery is usually defined as residual aneurysms. Recurrent aneurysms develop in the area of excluded aneurysm in long-term period after surgery. The authors analyze foreign and national literature data on the diagnosis and management of residual and recurrent aneurysms. Risk factors, the most common classifications, diagnostic methods and surgical treatment are presented.

Coil Embolization with Subsequent Subacute Flow Diversion Before Hospital Discharge as a Treatment Paradigm for Ruptured Aneurysms

BACKGROUND

Subtotal coil embolization followed by subsequent flow diversion is often pursued for treatment of acutely ruptured aneurysms. Owing to the need for anti-platelet therapy, the optimal time of safely pursuing flow diversion treatment has not been fully elucidated. In this study, we aim to demonstrate the safety and feasibility of staged treatment of acutely ruptured aneurysms with early coil embolization followed by flow diversion prior to discharge.

METHODS

A retrospective study to evaluate clinical outcomes of patients who presented with aneurysmal subarachnoid hemorrhage and underwent coil embolization followed by subacute flow diversion treatment during the same hospitalization.

RESULTS

A total of 18 patients are included in our case series. Eight patients presented with Hunt-Hess (H-H) grade 2 bleed, 6 patients with H-H grade 3, and 2 patients each with H-H grade 4 and H-H grade 1. Eight patients required placement of an external ventricular drain on admission. After initial coil embolization, 12 achieved Raymond-Roy grade 2 occlusion, and 6 attained grade 3a/b occlusion. The mean duration between coil embolization and subsequent flow diversion was 9.83 days (range: 1-30). There were no instances of re-hemorrhage between initial coil embolization and subsequent flow diversion treatment. Sixteen patients had a minimum of 6-month follow-up, of which 15 were found to have complete occlusion, and 1 required subsequent clipping.

CONCLUSIONS

Subtotal coil embolization followed by definitive treatment using flow diversion during the same hospitalization is feasible and achieves excellent aneurysm occlusion rates while avoiding dual anti-platelet therapy during the initial hemorrhage period.

Incidence rate and predictors of recurrent aneurysms after clipping: long-term follow-up study of survivors of subarachnoid hemorrhage

Recurrent aneurysms are a major cause of re-aneurysmal subarachnoid hemorrhage (aSAH), but information on long-term clip durability and predictors is insufficient. This study aimed to present the incidence rate of > 10 years and investigate predictors of a recurrent aneurysm in aSAH survivors. We included 1601 patients admitted with aSAH and treated by microsurgical clipping between January 1993 and May 2010. Of these patients, 435 aSAH survivors were included in this study (27.2%). The total follow-up time was 5680.9 patient-years, and the overall incidence rate was 0.77% per patient-year. The cumulative probability of recurrence without residua and regrowth of the neck remnant was 0.7% and 13.9% at 10 years, respectively. Neck remnant (hazard ratio [HR], 10.311; 95% confidence interval [CI], 5.233-20.313) and alcohol consumption over the moderate amount (HR, 3.166; 95% CI, 1.313-7.637) were independent risk factors of recurrent aneurysm. Current smoking and multiplicity at initial aSAH presentation were significant factors in a univariate analysis. Furthermore, de novo intracranial aneurysms (DNIAs) were more common in the recurrent group than in the non-recurrent group (40.9% vs. 11.5%, P < 0.001). In the present study, we noted the long-term clip durability and predictor of recurrence after microsurgical clipping. These findings can assist clinicians in identifying patients at a high risk of recurrent aneurysm and recommending selective long-term surveillance after microsurgical clipping.

Risk factors for repeated recurrence of cerebral aneurysms treated with endovascular embolization

Purpose

To explore the risk factors of recurrence after second endovascular embolization of recurrent aneurysms and the characteristics of recurrent refractory aneurysms to help clinical decision-making.

Materials and methods

Forty-nine patients with recurrent aneurysms who underwent repeated embolization were retrospectively enrolled and divided into the recurrent and non-recurrent group. The risk factors of recurrence, complications and follow-up results of repeated embolization, and characteristics of recurrent refractory aneurysms were analyzed.

Results

Among the 49 patients with the second embolization, 5 were lost to follow-up, 9 recurred, and 35 did not. Univariate analysis showed that aneurysm size (P = 0.022), aneurysm classification (P = 0.014), and Raymond-Roy grade after the second embolization (P = 0.001) were statistically different between the two groups. Multivariate analysis demonstrated the Raymond-Roy grade as an independent risk factor for the recurrence of aneurysms after the second embolization (P = 0.042). The complication rate after the second embolization was 4%. There were five recurrent refractory aneurysms with an average aneurysm size of 23.17 ± 10.45 mm, including three giant aneurysms and two large aneurysms. To achieve complete or near-complete embolization of the recurrent refractory aneurysms, multiple treatment approaches were needed with multiple stents or flow diverting devices.

Conclusion

Aneurysm occlusion status after the second embolization is an independent risk factor for the recurrence of intracranial aneurysms. Compared with near-complete occlusion, complete occlusion can significantly reduce the risk of recurrence after second embolization. In order to achieve complete or near-complete occlusion, recurrent refractory aneurysms need multiple treatments with the use of multiple stents or flow diverting devices.

Intrasaccular flow disruption for brain aneurysms: a systematic review of long-term outcomes

OBJECTIVE

The long-term safety and efficacy of intrasaccular flow disruption (IFD) for the treatment of brain aneurysms remain unclear. With accumulating experience and increasing use of IFD devices, recent studies have provided additional data regarding their outcomes. This review summarizes the long-term outcomes of IFD-treated brain aneurysms.

METHODS

A systematic literature review was performed on May 23, 2021, in PubMed, Web of Science, and Ovid MEDLINE for aneurysm treatment outcomes with IFD devices. Procedural details, including use of adjunctive devices and complications, were collected. The quality of studies was assessed using the Downs and Black checklist. Angiographic outcomes were classified as complete occlusion, residual neck, and residual aneurysm. Other outcomes included need for retreatment, permanent neurological deficit, and mortality. Pooled analyses were performed.

RESULTS

The final analysis comprised 1217 patients with 1249 aneurysms from 22 studies. The mean aneurysm diameter and neck width were 6.9 and 4.5 mm, respectively, and 27.6% of aneurysms were ruptured. The complete occlusion rates at 12 months and final follow-up (pooled mean duration 15.7 months) were 50.1% and 58.2%, respectively. Adjunctive devices were used in 6.4% of cases. The rates of hemorrhage, symptomatic infarction, permanent neurological deficit, and mortality were 1.2%, 2.8%, 1.0%, and 2.6%, respectively.

CONCLUSIONS

IFD is a very safe treatment for appropriately selected brain aneurysms with low complication and neurological deterioration rates. However, complete occlusion is achieved in only half of IFD-treated aneurysms at 1 year with a modest increase beyond this time point. As the majority of the studies were single arm, the pooled data are subject to selection and reporting biases. Future device developments, increased operator experience, and direct comparisons with alternative endovascular strategies and surgical clipping may clarify the role of IFD in aneurysm management.

Intrasaccular Flow Disruptor-Assisted Coiling of Intracranial Aneurysms Using the Novel Contour Neurovascular Systems and NEQSTENT: A Single-Center Safety and Feasibility Study

Background: Intrasaccular flow disruptors (IFD) have been introduced in the treatment of intracranial aneurysms (IAs) to overcome the low aneurysm occlusion rate and the high recanalization rate of the coiling technique. Among them, the Contour Neurovascular System (CNS) and the Neqstent (NQS) were designed to reconstruct the aneurysmal neck and both can be used as assisting coiling devices. We aimed to report our preliminary experience with the flow disruptor-assisted coiling (IFD-AC) technique. Methods: We performed a retrospective analysis of prospectively collected data of all patients with IAs treated with the IFD-AC. Results: Between February 2021 and April 2022, we treated 15 IAs with the IFD-AC: 10 ruptured and 5 unruptured. The IFD-AC was successfully performed in 13 cases, with a post-operative RROC 1 in 12 cases (92.3%) and RROC 2 in 1 case (7.7%). There was one ischemic event (6.7%) and no hemorrhagic complications. Twelve patients underwent a mid-term radiologic follow-up: Ten IAs (83.4%) presented an adequate occlusion, while 2 (16.7%) had a recurrence. Conclusions: The IFD-AC, both with the CNS and the NQS, seems a safe technique with promising efficacy profile. The IFD-AC has proved to be safe without antiplatelet therapy in ruptured cases. Further studies are needed to confirm our preliminary results.

Staged treatment for ruptured wide-neck intracranial aneurysm with intentional partial coiling in the acute phase followed by definitive treatment

Background:

Evidence supports endovascular coiling for ruptured intracranial aneurysms (RIAs). However, in some cases, it is difficult to achieve complete occlusion by coiling, such as with wide-neck aneurysms. We report our experience with intentional staged RIA treatment using targeted endovascular coiling at the rupture point in the acute phase, followed by delayed stent-assisted coiling, flow diverter stenting, or surgical clipping.

Methods:

Consecutive patients with RIAs treated between April 2015 and June 2021 were retrospectively investigated. Clinical characteristics, treatment complications, and patient outcomes data were collected.

Results:

Among 108 RIAs treated in our hospital, 60 patients underwent initial coiling; 10 patients underwent staged treatment. The aneurysm locations were the anterior communicating artery (n = 5), internal carotid-posterior communicating artery (n = 3), internal carotid-paraclinoid (n = 1), and vertebral artery-posterior inferior cerebellar artery (n = 1). The mean ± standard deviation aneurysmal diameter was 9.6 ± 5.4 mm and the mean aspect ratio was 1.2 ± 0.7. As the second treatment to obliterate blood flow to the neck area, we performed five stent-assisted coiling, two flow-diverter stentings, and three surgical clippings. Only one minor perioperative complication occurred. The median duration between the first and second treatments was 18 days (range, 14– 42 days). Good clinical outcome (modified Rankin scale score 0–2) at 90 days was achieved in 5 (50%) cases. The median follow-up duration was 6.5 months (range, 3–35 months); no rerupture occurred.

Conclusion:

Intentional staged treatment with a short time interval for RIA was effective and feasible.

Long-term clinical and angiographic outcome of the Woven EndoBridge (WEB) for endovascular treatment of intracranial aneurysms

The Woven EndoBridge (WEB) is a well-established device for endovascular treatment of wide-necked bifurcation aneurysms. The objective was to evaluate the long-term angiographic outcome of the WEB and to identify factors that influence aneurysm occlusion. Patient, aneurysm and procedural characteristics of 213 consecutive patients treated with the WEB at three German tertiary care centers between 2011 and 2020 were retrospectively reviewed. Aneurysm occlusion was determined immediately after the procedure, at mid-term (≤ 12 months) and at long-term (> 12 months) follow-up. Among 182 included aneurysms (mean diameter: 7.0 ± 2.4, mean neck width: 4.3 ± 1.6 mm), 29.7% were ruptured. The novel WEB 17 was used in 41.8%, and 11.0% were treated in combination with coiling and/or stenting. Complete and adequate occlusions were observed in 101/155 (65.2%) and 133/155 (85.8%) at mid-term, respectively, and in 59/94 (62.8%) and 87/94 (92.6%) at long-term follow-up (median: 19 months), respectively. Among 92 patients available for both mid- and long-term follow-up, occlusion was stable in 72.8%, improved in 16.3% and worsened in 10.9%. There were no major recurrences leading to aneurysm remnants between mid- and long-term follow-up. Retreatment was performed in 10/155 (6.5%) during mid-term and in 1/94 (1.0%) during long-term follow-up. The WEB provides durable aneurysm occlusion at the long-term. Nevertheless, follow-up imaging is necessary to identify late recurrences that may occur in around 10%.

Noncurative microsurgery for cerebral aneurysms: a systematic review and meta-analysis of wrapping, residual, and recurrence rates

OBJECTIVE

Microsurgery for cerebral aneurysms is called definitive, yet some patients undergo a craniotomy that results in noncurative treatment. Furthermore, the overall rate of noncurative microsurgery for cerebral aneurysms is unclear. The objective of this study was to complete a systematic review and meta-analysis to quantify three scenarios of noncurative treatment: aneurysm wrapping, postclipping remnants, and late regrowth of completely obliterated aneurysms.

METHODS

A PRISMA-guided systematic literature review of the MEDLINE and Cochrane Library databases and meta-analysis was completed. Studies were included that detailed rates of aneurysm wrapping, residua confirmed with imaging, and regrowth after confirmed total occlusion. Pooled rates were subsequently calculated using a random-effects model. An assessment of statistical heterogeneity and publication bias among the included studies was also completed for each analysis, with resultant I2 values and p values determined with Egger's test.

RESULTS

Sixty-four studies met the inclusion criteria for final analysis. In 41 studies, 573/15,715 aneurysms were wrapped, for a rate of 3.5% (95% CI 2.7%-4.2%, I2 = 88%). In 43 studies, 906/13,902 aneurysms had residual neck or dome filling, for a rate of 6.4% (95% CI 5.2%-7.6%, I2 = 93%). In 15 studies, 71/2568 originally fully occluded aneurysms showed regrowth, for a rate of 2.1% (95% CI 1.2%-3.1%, I2 = 58%). Together, there was a total rate of noncurative surgery of 12.0% (95% CI 11.5%-12.5%). Egger's test suggested no significant publication bias among the studies. Meta-regression analysis revealed that the reported rate of aneurysm wrapping has significantly declined over time, whereas the rates of aneurysm residua and recurrence have not significantly changed.

CONCLUSIONS

Open microsurgery for cerebral aneurysm results in noncurative treatment approximately 12% of the time. This metric may be used to counsel patients and as a benchmark for other treatment modalities. This investigation is limited by the high degree of heterogeneity among the included studies.

Delayed rupture of an anterior communicating artery aneurysm after elective Woven EndoBridge embolization, re-treated with microsurgical clipping: operative technique and systematic review

BACKGROUND

The Woven EndoBridge (WEB) device is designed for intrasaccular flow disruption for embolization of intracranial aneurysms. In limited experience so far, the rate of rupture after adequate occlusion by embolization is low.

TECHNICAL REPORT

A 58-year-old man initially had an incidental, unruptured 10.4 mm anterior communicating artery (ACoA) aneurysm treated with WEB embolization. Although his 6-month follow-up angiogram showed adequate occlusion of the aneurysm, he presented to our facility with aneurysmal recurrence due to WEB compaction and rupture. This was treated with surgical clipping of the aneurysm.

METHODS

The literature was systematically reviewed for cases of delayed rupture after WEB embolization. Statistical analyses included studies with at least 20 patients and follow-up of 3 months.

RESULTS

We identified 36 studies, which were primarily retrospective observational studies. The rate of complete occlusion ranged from 33% to 89%, and the rate of re-treatment ranged from 1.5% to 27%. Across four studies, the rate of recanalization ranged from 8.7% to 13%. Two cases of delayed rupture were reported; an additional four cases were found in case reports and case series. In only one previous case, the aneurysm was reported as previously untreated.

CONCLUSION

Early retrospective data has begun to define the history of WEB-treated aneurysms. Rupture of a previously unruptured, WEB-treated aneurysm with adequate initial occlusion is rare. We describe such a case with techniques for management, demonstrating that aneurysm recurrence and delayed rupture is possible despite good interim angiographic result. This report raises questions about follow-up for WEB-treated aneurysms.

Clipping Could Be the Best Treatment Modality for Recurring Anterior Communicating Artery Aneurysms Treated Endovascularly

BACKGROUND

The anterior communicating artery (AcoA) is the most common location for intracranial aneurysms.

OBJECTIVE

To present occlusion outcomes, complication rate, recurrence rate, and predictors of recurrence in a large cohort with AcoA aneurysms treated primarily with endosaccular embolization. We also attempt to present data on the most effective treatment modality for recurrent AcoA aneurysms.

METHODS

This is a retrospective, single-center study, reviewing the outcomes of 463 AcoA aneurysms treated endovascularly between 2003 and 2018.

RESULTS

The study cohort consisted of 463 patients. Adequate immediate occlusion was achieved in 418 (90.3%). Independent functional status at discharge was observed in 269 patients (58.0%), and the mortality rate was 6.8% (31). At 6 months, adequate occlusion was achieved in 418 (90.4%). Of all the patients, recurrence was observed in 101 cases (21.8%), and of those, 98 (22.4%) underwent retreatment. The combined frequency of retreatment for the coiling group was 42.4%, which was significantly higher than the 0 incident of retreatment in the clipping group (P < .0001). Among the retreatment cohort, there was a significantly higher subsequent retreatment rate in the endovascular group (0% in the clipping group vs 42.4% in the endovascular group, P < .0001).

CONCLUSION

Coiling with and without stent/balloon assistance is a relatively safe and effective modality for the treatment of AcoA aneurysms; however, in the setting of recurrence, microsurgical reconstruction leads to improved outcomes regarding durable occlusion, thus avoiding the potential for multiple interventions in the future.

Clinical Trials of Microsurgery for Cerebral Aneurysms: Past and Future

BACKGROUND

New findings and research regarding the microsurgical treatment of intracerebral aneurysms (IAs) continue to advance even in the era of endovascular therapies. Research in the past 2 decades has continued to revolve around the question of whether open surgery or endovascular treatment is preferable. The answer remains both complex and in flux.

OBJECTIVE

This review focuses on microsurgery, reflects on the research decisions of previous landmark studies, and proposes future study designs that may further our understanding of IAs and how best to treat them.

RESULTS

The future of IA research may include a combination of pragmatic trials, artificial intelligence integrated tools, and mining of large data sets, in addition to the publication of high-quality single-center studies.

CONCLUSIONS

The future will likely emphasize testing innovative techniques, looking at granular patient data, and considering every patient encounter as a potential source of knowledge, creating a system in which data are updated daily because each patient interaction contributes to answering important research questions.

Can further subdivision of the Raymond-Roy classification of intracranial aneurysms be useful in predicting recurrence and need for future retreatment following endovascular coiling?

Background:

The Raymond-Roy classification has been the standard for neck recurrences following endovascular coiling with three grades. Several modified classification systems with subdivisions have been reported in literature but it is unclear whether this adds value in predicting recurrence or retreatment. Our aim is to assess if these subdivisions aid in predicting recurrence and need for retreatment.

Methods:

A retrospective review of all patients undergoing endovascular coiling between 2013 and 2014. Patients requiring stent assistance or other embolization devices were excluded from the study. The neck residue was graded at time of coiling on the cerebral angiogram and subsequent 6, 24, and 60 months MRA. Correlation between grade at coiling and follow-up with need for subsequent retreatment was assessed.

Results:

Overall, 17/200 (8.5%) cases required retreatment within 5 years of initial coiling. 4/130 (3.1%) required retreatment within 5 years with initial Grade 0 at coiling, 6/24 cases (25%) of those Grade 2a, 4/20 cases (20%) Grade 2b, 3/8 (38%) Grade 3, and none of those with Grade 1. Large aneurysms ≥11 mm had an increased risk of aneurysm recurrence and retreatment. About 9.7% of ruptured aneurysms required retreatment versus 4.4% for unruptured. About 55% of carotid ophthalmic aneurysms were retreated.

Conclusion:

Although the modified classification system was significantly predictive of progressive recurrence and need for retreatment, no significant difference between the subdivisions of Grade 2 was observed. Similar predictive value was seen when using the Raymond-Roy classification compared to the new modified, limiting the usefulness of the new system in clinical practice.

Microsurgical clipping vs Woven EndoBridge (WEB) device for the management of unruptured wide-neck bifurcation aneurysms

The Woven EndoBridge device (WEB) was introduced in 2010 to treat wide-neck bifurcation aneurysms (WNBAs). Three landmark studies have been conducted to assess its safety and efficacy: WEBCAST, WEBCAST 2, and French Observatory Study. However, these studies have not compared its safety and efficacy to other treatment modalities. In this study, we compare WEB versus microsurgical clipping in the management of unruptured WNBA. We conducted a retrospective study of unruptured WNBA meeting the morphological criteria to be amenable for WEB treatment operated on at our institution. Surgical morbidity, mortality, and occlusion rates were assessed. We compared our results to those reported in the cumulative population of the three WEB landmark studies at 1 year. A total of 84 patients with 89 WNBA were included. The most common aneurysm location was the middle cerebral artery bifurcation (n = 67/89, 75%). No operative mortality was observed. Morbidity comprised small-vessel vasospasm (n = 1/89, 1%) resulting in hemiparesis vs. 3% morbidity for WEB (p = .324). All but one (n = 1/89, 1%) WNBA were completely occluded vs WEB occlusion rate of 53% at 1 year, statistically significantly worse (p < .001). In our analysis, we were not able to show superiority of WEB in terms of procedural morbidity in comparison to microsurgical clipping, defined as worsening in mRS. Microsurgical clipping achieves statistically significantly higher rates of complete aneurysm occlusion, thus posing the question of whether the WEB should be presented as a viable, comparable alternative to patients amenable to surgical treatment.

Interrater and intrarater agreement superior for three-dimensional digital subtraction angiography (3D-DSA) over 2D-DSA classification for detecting remnants after intracranial aneurysm clipping, a GRRAS Reliability and Agreement Study

BACKGROUND

Growing evidence suggests that three-dimensional digital subtraction angiography (3D-DSA) is superior to 2D-DSA in detection of intracranial aneurysm (IA) remnants after clipping. With a simple, practical quantitative scale proposed to measure maximal remnant dimension on 3D-DSA, this study provides a rigorous interrater and intrarater reliability and agreement study comparing this newly established scale with a commonly used (Sindou) 2D-DSA scale.

METHOD

Records of 43 patients with clipped IAs harboring various sized remnants who underwent 2D- and 3D-DSA between 2012 and 2018 were evaluated. Using the 2D and 3D scales, six raters scored these remnants and repeated the scoring task 8 weeks later. Interrater and intrarater agreement for both grading schemes were calculated using kappa (κ) statistics.

RESULTS

Interrater agreement was highly significant, yielding κ-values at 95% CI (p = 0.000) of 0.225 for the first [0.185; 0.265] and 0.368 s [0.328; 0.408] time points for 2D-DSA and values of 0.700 for the first [0.654; 0.745] and 0.776 s [0.729; 0.822] time points for 3D-DSA. Intrarater agreement demonstrated κ-values between 0.139 and 0.512 for 2D-DSA and between 0.487 and 0.813 for 3D-DSA scores.

CONCLUSION

Interrater and intrarater agreement was minimal or weak for 2D-DSA scores, but strong for 3D-DSA scores. We propose that baseline 3D-DSA characterization may prove more reliable when categorizing clipped IA remnants for purposes of risk stratification and lifelong follow-up.

Repeated Aneurysm Intervention

Over the past 25 years the endovascular treatment of cerebral aneurysms has gained preference in some countries over the traditional surgical procedures. The review part of the article clearly demonstrates that the clinical results of both modalities are similar and the difference is seen only in technical effectivity. Surgical techniques fail far less frequently than the endovascular ones. Incompletely occluded or growing aneurysms after the endovascular approach expose the patient to the risk of rebleeding with all possible consequences. Markedly repeated procedures are much more common for endovascularly treated aneurysms, again with all the risks.In the authors institution over the past 20 years, a total of 2032 aneurysms were treated. In 1263 endovascularly managed aneurysms the regrowth or inclomplete initial occlusion necessitated 159 repeated propcedures (12.6%). In surgical group the total of 27 aneurysms needed retreatment (3.5%). The difference is statistically significant. In nine patients in endovascular group the rebleeding was the reason for repeated procedures. No rebleeding was seen in the surgical group.This fact, also shown in the review part of the article, is important in patients counseling. Given the similar clinical results of both modalities the patient should be advised on the necessity of repeated follow-ups and of possible technical failure and eventual repeated procedure which is more likely if endovascular procedure is chosen.

Posterior Circulation Aneurysms

Posterior circulation aneurysms have a higher tendency to rupture and become symptomatic in comparison to anterior circulation aneurysms. Current treatment modalities for aneurysms in these locations vary widely including microsurgical clipping, trapping with bypass, wrapping, and various endovascular methods such as coiling, balloon or stent-assisted coiling, flow diversion, and vessel sacrifice, among others.Overall, surgical versus endovascular treatment of posterior circulation aneurysms continue to be a controversial topic in cerebrovascular neurosurgery. At our center, multi-disciplinary assessments including surgeons capable of both endovascular and microsurgical treatments of these aneurysms are employed to guide the treatment strategies. As advancements in both fields are made, this will continue to be a topic for debate. Anatomy and individual patient's characteristics will dictate the correct approach and therefore proficiency in the microsurgical techniques required to treat these aneurysms will continue to be both relevant and important.

Avenir® vs. AxiumTM Coils for the Treatment of Intracranial Aneurysms: Results of a Multicenter Randomized Controlled Trial With Short-Term Follow-Up

Purpose

Endovascular coil occlusion is a successful and rapidly evolving strategy used to treat patients who present with intracranial aneurysms. This study aimed to compare the safety and efficacy of the Avenir® and Axium^TM passive mechanically detachable coil systems.

Methods

A prospective, multicenter, randomized controlled study was carried out at ten medical centers from March 2018 to December 2019. A series of consecutive patients diagnosed with intracranial aneurysms were randomly assigned to undergo endovascular treatment with either the Avenir® or the Axium^TM mechanically detachable coil systems. The short-term outcomes from the two groups were compared with a focus on treatment efficacy and safety.

Results

A total of 162 and 161 patients were enrolled in the Avenir and Axium groups, respectively. The rate of successful coil detachment was 100% for the Avenir group and 99.38% for the Axium group. At the six-month follow-up visit, the overall aneurysm occlusion rate was 94.66% for the Avenir group and 96.95% for the Axium group (p > 0.05). We observed no statistically significant differences in clinical condition (as per the modified Rankin Scale) or the degree of aneurysm occlusion (as determined by digital subtraction angiography [DSA] and Raymond-Roy Occlusion Classification). Surgical complications were reported in 27 subjects in the Avenir group and 22 in the Axium group (p > 0.05). DSA performed at 6 months revealed complete aneurysm occlusion in 84 and 86% of patients in the Avenir and Axium groups, respectively.

Conclusion

We observed no significant short-term differences with respect to efficacy or safety when using either Avenir® or Axium^TM coils for the treatment of intracranial aneurysms.

Sex Differences in Cerebral Aneurysms and Subarachnoid Hemorrhage

Sex differences in cerebral aneurysm occurrence and characteristics have been well described. Although sex differences in outcomes following ischemic stroke have been identified, the effect of sex on outcomes following hemorrhagic stroke, and in particular, aneurysm treatment has been less studied. We describe the current state of knowledge regarding the impact of sex on treatment and outcomes of cerebral aneurysms. Although prior studies suggest that aneurysm prevalence and progression may be related to sex, we did not find clear evidence that outcomes following subarachnoid hemorrhage vary based on sex. Last, we identify areas for future research that could enhance understanding of the role sex plays in this context.

Clipping versus coiling for treatment of middle cerebral artery aneurysms: a retrospective Italian multicenter experience

Endovascular treatment has emerged as the predominant approach in intracranial aneurysms. However, surgical clipping is still considered the best treatment for middle cerebral artery (MCA) aneurysms in referral centers. Here we compared short- and long-term clinical and neuroradiological outcomes in patients with MCA aneurysms undergoing clipping or coiling in 5 Italian referral centers for cerebrovascular surgery. We retrospectively reviewed 411 consecutive patients admitted between 2015 and 2019 for ruptured and unruptured MCA aneurysm. Univariate and multivariate analyses of the association between demographic, clinical, and radiological parameters and ruptured status, type of surgical treatment, and clinical outcome at discharge and follow-up were performed. Clipping was performed in 340 (83%) cases, coiling in 71 (17%). Clipping was preferred in unruptured aneurysms and in those showing collateral branches originating from neck/dome. Surgery achieved a higher rate of complete occlusion at discharge and follow-up. Clipping and coiling showed no difference in clinical outcome in both ruptured and unruptured cases. In ruptured aneurysms age, presenting clinical status, intracerebral hematoma at onset, and treatment-related complications were significantly associated with outcome at both short- and long-term follow-up. The presence of collaterals/perforators originating from dome/neck of the aneurysms also worsened the short-term clinical outcome. In unruptured cases, only treatment-related complications such as ischemia and hydrocephalus were associated with poor outcome. Clipping still seems superior to coiling in providing better short- and long-term occlusion rates in MCA aneurysms, and at the same time, it appears as safe as coiling in terms of clinical outcome.

Risk of Re-Rupture, Vasospasm, or Re-Stroke after Clipping or Coiling of Ruptured Intracranial Aneurysms: Long-Term Follow-Up with a Propensity Score-Matched, Population-Based Cohort Study

Scarce evidence is available in Asia for estimating the long-term risk and prognostic factors of major complications such as re-rupture, vasospasm, or re-stroke for patients with aneurysmal subarachnoid hemorrhage (SAH) undergoing endovascular coil embolization or surgical clipping. This is the first head-to-head propensity score-matched study in an Asian population to demonstrate that endovascular coil embolization for aneurysmal SAH treatment is riskier than surgical clipping in terms of re-rupture, vasospasm, or re-stroke. In addition, the independent poor prognostic factors of vasospasm or re-stroke were endovascular coil embolization, male sex, older age (≥65 years; the risk of vasospasm increases with age), hypertension, congestive heart failure, diabetes, previous transient ischemic attack, or stroke in aneurysmal SAH treatment. Background: To estimate the long-term complications and prognostic factors of endovascular coil embolization or surgical clipping for patients with ruptured aneurysmal subarachnoid hemorrhage (SAH). Methods: We selected patients diagnosed with aneurysmal SAH between 1 January 2011 and 31 December 2017. Propensity score matching was performed, and Cox proportional hazards model curves were used to analyze the risk of re-rupture, vasospasm, and re-stroke in patients undergoing the different treatments. Findings: Multivariate Cox regression analysis revealed that the adjusted hazard ratio (aHR) of re-rupture for endovascular coil embolization compared with surgical clipping was 1.36 (95% confidence interval [CI]: 1.17–1.57; p < 0.0001). The aHRs of the secondary endpoints of vasospasm and re-stroke (delayed cerebral ischemia) for endovascular coil embolization compared with surgical clipping were 1.14 (1.02–1.27; p = 0.0214) and 2.04 (1.83–2.29; p < 0.0001), respectively. The independent poor prognostic factors for vasospasm and re-stroke were endovascular coil embolization, male sex, older age (≥65 years; risk increases with age), hypertension, congestive heart failure, diabetes, and previous transient ischemic attack or stroke. Interpretation: Endovascular coil embolization for aneurysmal SAH carries a higher risk than surgical clipping of both short- and long-term complications including re-rupture, vasospasm, and re-stroke.

The Combination of Stent and Antiplatelet Therapy May Be Responsible of Parenchymal Magnetic Susceptibility Artifacts after Endovascular Procedure

The aim was to assess the occurrence of magnetic susceptibility artifacts (MSA) following endovascular treatment of intracranial aneurysm by stent using susceptibility weighted imaging (SWI). Imaging and clinical data of 46 patients who underwent stent placement in the case of intracranial aneurysm endovascular treatment (S-Group) were retrospectively analyzed and compared to a control group (C-Group) in which 46 patients had coiling alone. The mean number of MSA was higher in the S-group than in the C-group on postprocedural SWI sequence (8.76, 95%CI [5.76; 11.76] vs. 0.78 [0.32; 1.25], respectively, p < 0.001) with a higher frequency of the appearance of MSA also in the S-group (78.26% vs. 21.74% in the C-group, p < 0.001). In the S-group, in the vascular territory of the treated artery, there was a higher number of MSA than in other vascular territories (mean of 5.18 [3.43; 6.92] vs. 3.08 [1.79; 4.36], p = 0.001). An odds ratio (OR) of 20.98 [5.24; 83.95] suggested a higher proportion of onset of MSA in the S-group than in the C-group (p < 0.001). The appearance of MSA after a treatment by stenting for intracranial aneurysm in patients under antiplatelet therapy was common, particularly in the treated artery territory.

Patient and aneurysm factors associated with aneurysm recanalization after coiling

BACKGROUND

One limitation of the endovascular treatment of intracranial aneurysms is aneurysm recanalization. The Analysis of Recanalization after Endovascular Treatment of intracranial Aneurysm (ARETA) study is a prospective multicenter cohort study evaluating the factors associated with recanalization after endovascular treatment.

METHODS

The current analysis is focused on patients treated by coiling or balloon-assisted coiling (BAC). Postoperative, mid-term vascular imaging, and evolution of aneurysm occlusion were independently evaluated by two neuroradiologists. A 3-grade scale was used for aneurysm occlusion (complete occlusion, neck remnant, and aneurysm remnant) and for occlusion evolution (improved, stable, and worsened). Recanalization was defined as any worsening of aneurysm occlusion.

RESULTS

Between December 2013 and May 2015, 16 French neurointerventional departments enrolled 1289 patients. A total of 945 aneurysms in 908 patients were treated with coiling or BAC. The overall rate of aneurysm recanalization at mid-term follow-up was 29.5% (95% CI 26.6% to 32.4%): 28.9% and 30.3% in the coiling and BAC groups, respectively. In multivariate analyses factors independently associated with recanalization were current smoking (36.6% in current smokers vs 24.5% in current non-smokers (OR 1.8 (95% CI 1.3 to 2.4); p=0.0001), ruptured status (31.9% in ruptured aneurysms vs 25.1% in unruptured (OR 1.5 (95% CI 1.1 to 2.1); p=0.006), aneurysm size ≥10 mm (48.8% vs 26.5% in aneurysms <10 mm (OR 2.6 (95% CI 1.8 to 3.9); p<0.0001), wide neck (32.1% vs 25.8% in narrow neck (OR 1.5 (95% CI 1.1 to 2.1); p=0.02), and MCA location (34.3% vs 28.3% in other locations (OR 1.5 (95% CI 1.0 to 2.1); p=0.04).

CONCLUSIONS

Several factors are identified by the ARETA study as playing a role in aneurysm recanalization after coiling: current smoking, aneurysm status (ruptured), aneurysm size (≥10 mm), neck size (wide neck), and aneurysm location (middle cerebral artery). This finding has important consequences in clinical practice.

TRIAL REGISTRATION NUMBER

URL: http://www.clinicaltrials.gov; Unique Identifier: NCT01942512.

Retreatment of previously treated intracranial aneurysm: Procedural complications and risk factors for complications

OBJECTIVE

Intracranial aneurysm (IA) is a frequent vascular malformation that can be managed by endovascular treatment (EVT) or microsurgery. A previously treated IA can recanalize, which may require further treatment. The aim of our study was to evaluate procedural complications related to IA retreatment and their risk factors.

METHODS

All patients retreated for IA between 2007 and 2017 in 4 hospitals were included. We retrospectively reviewed the frequency of procedural complications of IA retreatment, defined as death or≥1-point increase in modified Rankin score 24h after the procedure. We then screened for risk factors of procedural complications by comparing the characteristics of patients with and without complications.

RESULTS

During the inclusion period, 4,997 IAs were treated in our 4 institutions. Of these, 237 (4.7%) were retreated. 29 (12.2%) had≥1 procedural complication. However, severe complications, defined as death or dependency at 1 month, occurred only in 3 patients (1.3%). The only risk factor for complications was microsurgical clipping as retreatment.

CONCLUSIONS

Procedural complications during IA retreatment were frequent but, in most cases, retreatment did not lead to death or severe disability. The only risk factor for complications of IA retreatment was clipping as retreatment. However, the design of the study did not allow any conclusion to be drawn as to the optimal means of aneurysm retreatment, and further studies are needed.