Acutely Ruptured Intracranial Aneurysms Treated with Flow-Diverter Stents: A Systematic Review and Meta-Analysis

Long-term Safety and Efficacy of the Derivo Embolization Device in a Single-center Series

PURPOSE

This study analyzes the long-term clinical and angiographic outcomes of the Derivo Embolization Device (DED), an advanced flow diverter device with an electropolished surface, for the treatment of intracranial aneurysms.

METHODS

A consecutive series of 101 patients (mean age: 58 years, 72% female) treated with the DED for 122 aneurysms at a single center between 2017 and 2023 was retrospectively analyzed for major (change in National Institutes of Health Stroke Scale [NIHSS] score ≥ 4 points) and minor (change in NIHSS score < 4 points) neurological events, procedural morbidity (increase of at least one point on the modified Rankin Scale), and angiographic results.

RESULTS

There were 14 (11%) recurrent aneurysms, 15 (12%) ruptured aneurysms, 26 (21%) posterior circulation aneurysms and 16 (13%) fusiform or dissecting aneurysms. Device deployment failed in 1 case (1%). Procedure-related symptomatic procedural complications consisted of 2 (2%) major events (1 major stroke and 1 vessel perforation with intracranial hemorrhage and infarction) and 6 minor events (6 minor strokes). Procedural morbidity was 5%. There were no late ischemic or hemorrhagic events during follow-up. Complete and favorable aneurysm occlusion was achieved in 54% (40/74) and 62% (46/74) at a mean of 5 months, 71% (27/38) and 87% (33/38) at a mean of 12 months, and 76% (25/33) and 97% (32/33) at a mean of 35 months, respectively.

CONCLUSION

The results demonstrate progressive aneurysm occlusion beyond 12 months after DED implantation with an almost 100% favorable occlusion rate. Procedural morbidity was low and there were no late complications.

Silk vista baby flow diversion beyond the circle of Willis: A single-center experience with long-term outcomes

INTRODUCTION

There is a lack of evidence of flow diversion (FD) safety for aneurysms treatment beyond the circle of Willis. Therefore, we provide a single-center real-world experience with the Silk Vista Baby (SVB).

METHODS

A single-center database was retrospectively reviewed for aneurysms treated with SVB flow diverters. Demographic information, clinical presentation, radiographic characteristics, procedural complications, and outcomes were assessed.

RESULTS

About 57 patients (66.7% female, mean age 54.3 ± 13.2) encompassing 57 aneurysms were included. Overall, 40.4% were ruptured: 68.4% saccular, 17.5% blister, 8.7% fusiform, and 5.3% dissecting. The majority were in the anterior circulation (68.4%), and in 48.2% of cases, the distal vessel diameter was inferior to 2 mm. The symptomatic ischemic rate was 5.2%, with one case due to in-stent thrombosis (1.8%). There were no hemorrhagic complications. Complication rates did not differ between ruptured and unruptured lesions (p = 0.356). There were no cases of delayed aneurysm rupture, and overall mortality was 1.8%. The median follow-up time was 18 ± 12 months. In-stent stenosis rate was 10.5% (6/57), all of which were asymptomatic. At the last follow-up, 70.2% of cases had an adequate occlusion (OKM C and D), and 96.5% had an mRS of 0-2.

CONCLUSION

In our series, SVB was shown to be a safe device in the treatment of not only distal anterior circulation aneurysms but also in the management of complex posterior fossa and ruptured blister aneurysms. Multicenter studies are needed to confirm and generalize these results.

Placement of an intrasaccular flow diverter in an intracranial sidewall aneurysm using the Bendit articulating microcatheter

Intrasaccular flow diversion is a new endovascular option for managing unruptured intracranial aneurysms.1-6 However, catheter ejection can occur during placement of an intrasaccular flow diverter, especially in tortuous vasculature that creates unfavorable angles between the aneurysm neck and the parent vessel.5 The Bendit steerable microcatheter (Bendit Technologies, Petah Tikva, Israel) can dynamically change its tip angle and may mitigate these placement concerns.7-9 Here, we report the placement of an intrasaccular flow diverter for the treatment of an unruptured internal carotid artery sidewall aneurysm at an unfavorable neck angle using the Bendit microcatheter (video 1). The Bendit was navigated around the 180° turn of the carotid siphon and held a stable position during device delivery. The device was sequentially deployed as the Bendit was progressively straightened and was successfully placed within the aneurysm. No neurological complications were experienced and the patient was asymptomatic on follow-up 3 months later. neurintsurg;16/10/1066/V1F1V1Video 1Placement of an intrasaccular flow diverter in an intracranial sidewall aneurysm using the Bendit articulating microcatheter.

An overview of decision-making in cerebrovascular treatment strategies: Part II - Ruptured aneurysms

Introduction

Decision-making for the treatment of ruptured aneurysms is an intricate process, which involves several factors. There has been a rapid advancement in endovascular, but also in the surgical treating field of ruptured intracranial aneurysms, with a growing body of evidence for either treatment technique.

Research question

As there is a wide variety of treatment possibilities, it can be hard to understand the intricacies which lie behind the decision-making process for a given aneurysm.

Materials and methods

An overview of the most relevant literature in decision-making on ruptured intracranial aneurysms is given.

Results

Different decision-altering factors were identified, which can be divided into information from the general evidence, to influential factors such as the patient's age, initial presenting status, and aneurysmal factors such as size, morphology and aneurysmal location.

Discussion and conclusion

This review provides an evidence-based overview of the most pertinent literature on these different aspects of decision-making in ruptured aneurysm cases and provides some recommendations after each of these segments. As always, all different aspects of the patient and aneurysmal factors should be taken into consideration before coming to a conclusion, as to obtain the best possible result for an individual patient.

Flow diverting stent monotherapy as the best choice in the treatment of intracranial blood blister-like aneurysms: a systematic review

OBJECTIVE

To evaluate the effectiveness and safety of flow-diverting stent (FDS) monotherapy in the treatment of intracranial blood blister-like aneurysms (BBAs) through a detailed systematic review.

METHODS

This review adheres to the PRISMA guidelines, focusing on studies utilizing FDS monotherapy for BBAs, spanning from July 2010 to November 2023. A systematic search across databases including Embase, Medline/PubMed, Scopus, and Google Scholar was conducted. Studies in English that solely used FDS for BBA treatment and assessed perioperative complications were included. Data from 23 studies encompassing 181 cases were systematically analyzed for patient demographics, aneurysm characteristics, treatment specifics, and outcomes.

RESULTS

The collected data indicates a dominant occurrence of BBAs in the internal carotid artery (86.9%), with a mean patient age of 50.27 years and a higher prevalence in females (73.43%). Treatment timing varied, with 45.9% treated within the first three days, 35.7% were treated between 4 and 14 days, and 18.4% of patients were treated after 14 days. The study found a complete occlusion rate of 88.1% in follow-up imaging and a favorable clinical outcome in 82.2% of cases. Periprocedural complications were reported in 19.2% of patients, with a related mortality rate of 3.9%.

CONCLUSIONS

The systematic review demonstrates that FDS monotherapy is highly effective and safe in the treatment of intracranial BBAs. It offers a high rate of complete aneurysm occlusion, favorable clinical outcomes, and low complication rates. These results highlight FDS monotherapy as a prominent treatment method, ensuring robust aneurysmal protection while maintaining the patency of the parent artery.

Flow diverter braid deformation following treatment of cerebral aneurysms: incidence, clinical relevance, and potential risk factors

BACKGROUND

Although flow diverters (FDs) have benefited from several technical improvements, recently concerns have arisen regarding the braid stability after implantation. Thus, we investigated frequency, predictive factors, and clinical impact of the phenomenon of FD braid deformation (FDBD).

METHODS

Consecutive intracranial aneurysms (IAs) treated with various FDs, between January 2018 and July 2023, were reviewed to identify FDBD (defined as the deformation of a FD without any external force applied to it). Patient, aneurysm, procedural, and FD characteristics were retrieved and analyzed using univariate and multivariable analyses. Morbidity is defined as a score of +1 in the modified Rankin Scale at 3 months.

RESULTS

In total, 245 FD procedures (271 FDs implanted; 25 multiple IAs treated with 1 FD) in 228 patients; FDBD was observed in 36/245 cases (14.7%), mainly at follow-up angiography (32/36, 88.9%); fish-mouthing was the most frequent FDBD. Morbidity was related to fish-mouthing and braid collapse and was significantly higher in the FDBD group after retreatment (p=0.04). Drawn filled tubing with platinum (DFT) (adjusted odds ratio (aOR)=7.0, 95% CI 3.0 to 17.5; p<0.001) and FD diameter (aOR=2.2, 95% CI 1.3 to 4.1; p<0.01) were identified as independent predictors of FDBD. The metal alloy composing the FD (p=0.13) and coated surfaces were not significantly associated with FDBD (p=0.54 in multivariable analysis).

CONCLUSIONS

FDBD is a frequent phenomenon observed in about 15% of cases, and it was responsible for higher morbidity. Only FD characteristics (DFT and FD diameter) were independent determinants of FDBD. Future research should focus on the impact of novel braid configurations and materials on braid stability.

Flow diversion with hydrophilic polymer coating with prasugrel as single antiplatelet therapy in the treatment of acutely ruptured intracranial aneurysms: a multicenter case series, complication and occlusion rates

BACKGROUND

This study reports a multicenter experience of using hydrophilic polymer-coated (HPC) flow diverters with prasugrel single antiplatelet therapy to treat ruptured aneurysms with subarachnoid hemorrhage (SAH).

METHODS

Patients treated for intracranial aneurysms within 30 days after SAH with a p64/p48 MW HPC flow diverter were prospectively identified. Clinical presentation and outcomes, periprocedural and postprocedural complications, and degree of occlusion at follow-up were evaluated.

RESULTS

A total of 84 patients were treated in 88 sessions (54.5% women; mean age 53.3 years). Four patients (4.7%) experienced flow diverter-dependent complications. No cases of aneurysm re-rupture or hemorrhagic complications related to antiplatelet therapy were recorded. Immediate complete occlusion was achieved in 27.4% of cases (23/84). The rate of complete occlusion among survivors was 83% in early follow-up, 90.2% in mid-term follow-up, and 92.3% in the latest possible follow-up.

CONCLUSION

p64/p48 MW HPC flow diverters with prasugrel single antiplatelet therapy were associated with safety from aneurysm re-rupture and high occlusion rates at medium- and long-term follow-up in managing ruptured aneurysms. Adequate management of single antiplatelet therapy with prasugrel is crucial, particularly with higher doses than usual, to avoid both ischemic and hemorrhagic complications.

Flow Diversion for Endovascular Treatment of Intracranial Aneurysms: Past, Present, and Future Directions

Flow diversion for intracranial aneurysms emerged as an efficacious and durable treatment option over the last two decades. In a paradigm shift from intrasaccular aneurysm embolization to parent vessel remodeling as the mechanism of action, the proliferation of flow-diverting devices has enabled the treatment of many aneurysms previously considered untreatable. In this review, we review the history and development of flow diverters, highlight the pivotal clinical trials leading to their regulatory approval, review current devices including endoluminal and intrasaccular flow diverters, and discuss current and expanding indications for their use. Areas of clinical equipoise, including ruptured aneurysms and wide-neck bifurcation aneurysms, are summarized with a focus on flow diverters for these pathologies. Finally, we discuss future directions in flow diversion technology including bioresorbable flow diverters, transcriptomics and radiogenomics, and machine learning and artificial intelligence.

Evaluation of flow diverter use in acutely ruptured vertebral artery dissecting Aneurysms: A focus on safety and efficacy for rapid Aneurysm obliteration

OBJECTIVE

Flow diverter device (FDD) has emerged as the reconstruction technique for treating ruptured dissecting vertebral artery Aneurysms (VADA), but data on feasibility regarding re-rupture risk and timing of Aneurysm obliteration following FDD treatment is still limited. Therefore, this study aimed to evaluate the safety and efficacy of FDD in the treatment of VADAs presenting with subarachnoid hemorrhage (SAH).

METHODS

We retrospectively reviewed patients with ruptured VADA presenting with subarachnoid hemorrhage who underwent FDD placement at our institution between 2015 and 2023. Patient demographic data, Aneurysm configuration, and occlusion status were analyzed.

RESULTS

Thirteen patients with SAH from VADA rupture underwent FDD implantation. The average size of the largest diameter of the Aneurysm was 11.2 mm (range 6.5-21 mm). Eight of 13 (61.5 %) patients had their Aneurysms completely obliterated within 2 weeks after the procedure. The small dissecting Aneurysm (d = 0.636, p = 0.002) and degree of intra-Aneurysmal contrast stasis (d = 0.524, p = 0.026) were associated with rapid Aneurysm occlusion, according to the Somer's d coefficient. There were no ischemic or hemorrhagic complications at the average clinical follow-up of 28.4 months (range 5-67 months) and average angiographic follow-up of 20.1 months (range 3-60 months). A favorable outcome (mRS 0-2) was achieved in 12 patients (92.3 %).

CONCLUSIONS

FDD is safe and effective for the reconstruction of acutely ruptured VADAs. In addition, our study emphasizes that small dissecting Aneurysms tend to be rapidly obliterated after flow diversion, which eliminates the risk of re-rupture during the acute phase of subarachnoid hemorrhage.

The clinical challenge of subarachnoid hemorrhage associated with multiple aneurysms when the bleeding source is not certainly identifiable

BACKGROUND

Multiple intracranial aneurysms (IAs) are encountered in 20-30% of the subarachnoid hemorrhages (SAH). Neuroimaging and clinical examination are usually sufficient to detect the bleeding source, but sometimes it can be misdiagnosed with catastrophic consequences.

METHODS

We reviewed our diagnostic work-up for all patients admitted from January 2016 to December 2020 for SAH with multiple IAs accounting for our rate of diagnostic failure. Then, we grouped the patients into 4 categories according to aneurysms topography and described our operative protocol in case of uncertain bleeding origin.

RESULTS

Sixty-two patients harboring 161 IAs were included. The bleeding source was identified in 56 patients (90.3%), who harbored other 81 bystander aneurysms. In 6 cases (9.7%) with a total of 24 aneurysms we failed the bleeding source identification. According to IAs topography, we grouped the IAs multiplicity in: 1) anterior plus posterior circulation IAs; 2) multiple posterior circulation IAs; 3) bilateral anterior circulation IAs; and 4) multiple ipsilateral anterior circulation IAs. In case of unidentified bleeding source, key-elements favoring the simultaneous multiple IAs treatment were their number, morphology, topography, clinicians' experience, and management modality as endovascular treatment allows a faster exclusion of multiple IAs distant one each other compared with surgery. MCA involvement represented the more frequent reason to prefer multiple clipping rather than multiple coiling.

CONCLUSIONS

In a small percentage of patients with SAH with multiple IAs, bleeding source identification can be difficult. Until the routinely availability of new tools such as vessel wall imaging or computational fluid dynamics, an experienced neurovascular team and strategies aiming to simultaneously exclude multiple IAs remain mandatory.

Treatment of ruptured intracranial aneurysms using the novel generation of flow-diverters with surface modification: A systematic review and meta-analysis

BACKGROUND

Surface modification of flow diverters (FDs) has been explored as a solution for reducing thrombotic risk of these devices, without necessarily using dual antiplatelet therapy (DAPT). If effective, this could pose a promising alternative for treatment of ruptured aneurysms not amenable to other modalities.

METHODS

We performed a comprehensive search of PubMed, MEDLINE, and Embase databases following Preferred Reporting Items for Systematic reviews and Meta-analyzes guidelines. We included articles reporting use of surface-modified FDs for treatment of ruptured aneurysms. Demographics, subarachnoid hemorrhage (SAH) severity, aneurysm characteristics, devices used, periprocedural complications, angiographic outcomes, and mortality were extracted for sample size-based weighted analysis.

RESULTS

Six studies comprising 59 patients with 64 aneurysms were included. Mean patient age was 56.6 ± 6.3 years and 60.6% (95% confidence interval [CI], 46.7-72.9%) were women. The anterior circulation was the location in 60.4% (95%CI, 45.5-73.5%) of aneurysms; 41.8% of the aneurysms were saccular (95%CI, 29.3-55.4%), 16.7% were fusiform (95%CI, 8.3-30.8%), 29.9% were dissecting (95%CI, 12.8-55.4%), 24.4% were blood-blister (95%CI, 15.2-36.7%), and 5.7% were mycotic (95%CI, 2-15.1%). Poor SAH grade was reported in 46.9% (95%CI, 33.3-60.9%). Adjunctive coiling was used in 33.2% (95%CI, 12.4-63.6%). Periprocedural thromboembolic and hemorrhagic complications occurred in 20% (95%CI, 7.1-45.1%) and 8.8% (95%CI, 3.7-19.5%), respectively. Complete occlusion was achieved in 76.4% (95%CI, 58.1-88.3%); no retreatments during follow-up were reported. Overall mortality was 15.1% (95%CI, 7.7-27.6%). There were no differences between single antiplatelet therapy (SAPT) and DAPT regimens with respect to periprocedural thromboembolic complications (P = 0.09), hemorrhagic (P = 0.834) complications, and mortality (P = 0.312).

CONCLUSION

Surface-modified FD treatment of ruptured aneurysms resulted in high rates of thromboembolic complications and acceptable rates of hemorrhagic complications. A considerable proportion of aneurysms were nonsaccular. Rates of complete occlusion were high and retreatment were low. Importantly, no statistically significant difference was found between SAPT and DAPT with respect to complications and mortality.

Flow Diverters with Surface Modification in Patients with Intracranial Aneurysms: A Systematic Review and Meta-Analysis

BACKGROUND

Flow diverters with surface modification (FDSM) are increasingly being used in the treatment of intracranial aneurysms (ANs). We aimed to evaluate the effectiveness and safety across different devices and antiplatelet therapies using a systematic review and meta-analysis.

METHODS

A systematic review was performed to identify original studies of ≥10 patients with intracranial ANs treated with FDSM from database inception through August 2023. Primary effectiveness outcome was the rate of complete AN occlusion at follow-up ≥6 months. Safety outcomes included ischemic stroke, hemorrhage, and in-stent thrombosis, and were stratified by FDSM devices and antiplatelet therapies. Certainty of evidence was evaluated following the Grading of Recommendations, Assessment, Development, and Evaluations approach.

RESULTS

Twenty-seven studies were included, yielding 2161 patients with 2373 ANs. A total of 70.5% of the ANs were located on the internal carotid artery (ICA). Total 10.3% were acutely ruptured. The complete AN occlusion rate was 72.3% at follow-up ≥6 months. Sensitivity analysis in the ICA AN cohort yielded comparable occlusion rates between Pipeline Flex Embolization Device-Shield (80.4%) and Phenox-hydrophilic polymer-coated (77.5%, P = 0.54), but a lower 66.2% rate for Flow Redirection Endoluminal Device-X (P = 0.02). The rate of in-stent thrombosis and stenosis tended to be higher in Phenox-hydrophilic polymer-coated (3.4%) and Flow Redirection Endoluminal Device-X (4.3%) versus Pipeline Flex Embolization Device-Shield (0.8%, P = 0.05).

CONCLUSIONS

FDSM were safe with satisfactory effectiveness for intracranial ANs. More specific investigations are warranted to explore their performance in ANs beyond the ICA and optimal antiplatelet therapy.

Safety and efficacy of coated flow diverters in the treatment of ruptured intracranial aneurysms: a retrospective multicenter study

BACKGROUND

This multicenter study evaluated the safety and efficacy of coated flow diverters (cFDs) for the treatment of ruptured intracranial aneurysms.

METHODS

Consecutive patients treated with different cFDs for ruptured aneurysms under tirofiban at eight neurovascular centers between 2016 and 2023 were retrospectively analyzed. The majority of patients were loaded with dual antiplatelet therapy after the treatment. Aneurysm occlusion was determined using the O'Kelly-Marotta (OKM) grading scale. Primary outcome measures were major procedural complications and aneurysmal rebleeding during hospitalization.

RESULTS

The study included 60 aneurysms (posterior circulation: 28 (47%)) with a mean size of 5.8±4.7 mm. Aneurysm morphology was saccular in 28 (47%), blister-like in 12 (20%), dissecting in 13 (22%), and fusiform in 7 (12%). Technical success was 100% with a mean of 1.1 cFDs implanted per aneurysm. Adjunctive coiling was performed in 11 (18%) aneurysms. Immediate contrast retention was observed in 45 (75%) aneurysms. There was 1 (2%) major procedural complication (a major stroke, eventually leading to death) and no aneurysmal rebleeding. A good outcome (modified Rankin Scale 0-2) was achieved in 40 (67%) patients. At a mean follow-up of 6 months, 27/34 (79%) aneurysms were completely occluded (OKM D), 3/34 (9%) had an entry remnant (OKM C), and 4/34 (12%) had residual filling (OKM A or B). There was 1 (3%) severe in-stent stenosis during follow-up that was treated with balloon angioplasty.

CONCLUSIONS

Treatment of ruptured aneurysms with cFDs was reasonably safe and efficient and thus represents a valid treatment option, especially for complex cases.

Flow diversion of ruptured intracranial aneurysms: a single-center study with a standardized antithrombotic treatment protocol

BACKGROUND

The use of antithrombotic medication following acute flow diversion for a ruptured intracranial aneurysm (IA) is challenging with no current guidelines. We investigated the incidence of treatment-related complications and patient outcomes after flow diversion for a ruptured IA before and after the implementation of a standardized antithrombotic medication protocol.

METHODS

We conducted a single-center retrospective study including consecutive patients treated for acutely ruptured IAs with flow diversion during 2015-2023. We divided the patients into two groups: those treated before the implementation of the protocol (pre-protocol) and those treated after the implementation of the protocol (post-protocol). The primary outcomes were hemorrhagic and ischemic complications. A secondary outcome was clinical outcome using the modified Ranking Scale (mRS).

RESULTS

Totally 39 patients with 40 ruptured IAs were treated with flow diversion (69% pre-protocol, 31% post-protocol). The patient mean age was 55 years, 62% were female, 63% of aneurysms were in the posterior circulation, 92% of aneurysms were non-saccular, and 44% were in poor grade on admission. Treatment differences included the use of glycoprotein IIb/IIIa inhibitors (pre-group 48% vs. post-group 100%), and the use of early dual antiplatelets (pre-group 44% vs. 92% post-group). The incidence of ischemic complications was 37% and 42% and the incidence of hemorrhagic complications was 30% and 33% in the pre- and post-groups, respectively, with no between-group differences. There were three (11%) aneurysm re-ruptures in the pre-group and none in the post-group. There were no differences in mortality or mRS 0-2 between the groups at 6 months.

CONCLUSION

We found no major differences in the incidence of ischemic or hemorrhagic complications after the implementation of a standardized antithrombotic protocol for acute flow diversion for ruptured IAs. There is an urgent need for more evidence-based guidelines to optimize antithrombotic treatment after flow diversion in the setting of subarachnoid hemorrhage.

Flow Diversion for the Management of Posterior Circulation's Intracranial Aneurysms

The endovascular treatment of posterior circulation aneurysms, although challenging, has been well-established due to various factors that limit the surgical approach in most cases. Flow diversion has also been utilized in the treatment of such aneurysms, although its effectiveness and safety still require evaluation. Numerous studies have examined the outcomes and complication rates in patients treated with FD, resulting in varying findings. This review aimed to summarize the most recent literature concerning the effectiveness of flow diversion devices in posterior circulation aneurysms. Additionally, it highlights reports that compare results in the posterior versus anterior circulation, as well as flow diversion versus stent-assisted coiling.

Endovascular treatment of middle cerebral artery aneurysms: current status and future prospects

Middle cerebral artery (MCA) aneurysms are complex and widely distributed throughout the course of the MCA. Various types of aneurysms can occur in the MCA. Ruptured as well as unruptured MCA aneurysms may require treatment to avoid bleeding or rebleeding. Currently, clipping is regarded as the first-line choice for the treatment of MCA aneurysms. However, endovascular treatment (EVT) is emerging as an alternative treatment in selected cases. EVT techniques vary. Therefore, it is necessary to review EVT for MCA aneurysms. In this review, the following issues were discussed: MCA anatomy and anomalies, classifications of MCA aneurysms, the natural history of MCA aneurysms, EVT status and principle, deployments of traditional coiling techniques and flow diverters (FDs), and deployments and prospects of intrasaccular flow disruptors and stent-like devices. According to the review and our experience, traditional coiling EVT is still the preferred therapy for most MCA aneurysms. FD deployment can be used in selective MCA aneurysms. Parent artery occlusion (PAO) can be used to treat distal MCA aneurysms. In addition, new devices can be used to treat MCA aneurysms, such as intrasaccular flow disruptors and stent-like devices. In general, EVT is gaining popularity as an alternative treatment option; however, there is still a lack of evidence regarding EVT, and longer-term data are not currently available for most EVT devices.

Coiling embolization strategy for medium-to-giant-sized intracranial aneurysms treated with pipeline embolization device: a propensity score-weighted study

OBJECTIVES

We aim to investigate associations between different coil strategies and outcomes in the aneurysms treated by a pipeline embolization device (PED).

METHODS

Patients with medium-to-giant-sized aneurysms treated by PED were included. The total cohort was divided into PED-alone and PED-coiling groups, and the PED-coiling group was further divided into loose and dense packing subgroups. Multivariate logistic analyses and stabilized inverse probability of treatment weighting (sIPTW) were performed to investigate the relationships between coiling strategies and outcomes. Restricted cubic spline (RCS) curves were used to describe the coiling degree and angiographic outcome relationship.

RESULTS

A total of 398 patients with 410 aneurysms were included. Aneurysms treated with PED coiling had a lower incomplete occlusion rate (15.3% vs. 30.3%, p = 0.002), higher total perioperative complication rate (14.2% vs. 3.5%, p = 0.001), longer production time (142.14 min vs. 101.26 min, p < 0.001), and higher total cost ($45,158.63 vs. $34,680.91, p < 0.001) than those treated with PED alone. There were no differences in outcomes between the loose and dense packing subgroups. However, the total cost was higher in the dense packing group ($43,787.46 vs. $47,288.32, p = 0.001) than in the loose packing group. The result was still robust in the multivariate and sIPTW analyses. The RCS curves showed "L-shape" relationships between the coil degree and angiographic outcomes.

CONCLUSION

Compared with PED alone, PED coiling could improve aneurysm occlusion. However, it could also increase the total complication risk, prolong procedure time, and increase the total cost. Compared with loose packing, dense packing did not enhance the treatment effectiveness but increased the treatment cost.

CLINICAL RELEVANCE STATEMENT

The additional treatment effect from coiling embolization declines sharply after a certain point. Specifically, the aneurysm occlusion rate is roughly stable when the coil number is greater than 3 or the total coil length is longer than 150 cm.

KEY POINTS

• Compared with pipeline embolization device (PED) alone, PED combined with coiling can improve aneurysm occlusion. • Compared with PED alone, PED combined with coiling increases the total complication risk, cost, and prolongs procedure time. • Compared with loose packing, dense packing did not increase the treatment effectiveness but increased the cost.

Overlapping Stent Treatment for Ruptured Dissecting Aneurysms in Posterior Circulation

Ruptured dissecting aneurysms in posterior intracranial circulation present significant clinical challenges and often cause poor prognoses. Our cohort used overlapping stents as the primary treatment. We analyzed the medical records of 27 patients (18 men/nine women) with ruptured posterior circulation dissecting aneurysms (PCDAs). Their average age was 52 years. We selected 11 patients who used Enterprise (EP) and LVIS stents overlappingly and matched them 1:1 with counterparts who received either EP or LVIS stents individually. Overlapping stents was a feasible treatment in all 27 cases. We successfully followed up 26 patients for ≥6 months. Regrettably, one patient died from intracranial hypertension on Day 7 post-procedure. Immediate post-procedure angiographies indicated Raymond grade I, II, and III occlusions of PCDAs in 16 (59.3%), 7 (25.9%), and 4 (14.8%) cases, respectively. At an average follow-up duration of 16.2 months, 25 patients (96.2%) had modified Rankin Scale scores of 0-2, signifying positive outcomes. One patient (3.8%) had a score of 3-4. Recurrence rates for the EP and LVIS stent groups were higher than those of the overlapping stent group (45.45% vs. 9.09%, p = 0.15 and 27.27% vs. 9.09%, p = 0.59, respectively). No significant difference in recurrence rates existed between the overlapping and single-stent groups. Similarly, follow-up outcomes were consistent between the two groups. Overlapping stents could be an efficient method for treating ruptured PCDAs.

Trends in Ruptured and Unruptured Aneurysmal Treatment from 2010 to 2020: A Focus on Flow Diversion

OBJECTIVE

Flow diverters are a promising new tool in the neurosurgeon's arsenal for aneurysm management. We sought to quantify the trends of flow diversion in comparison to traditional endovascular coiling and surgical clip ligation techniques in the United States from 2010 to 2020 with an emphasis on aneurysm location and preferences in usage for ruptured versus unruptured aneurysms.

METHODS

In this large cross-sectional study, patients aged 18 and older within the MARINER database were analyzed. Descriptive characteristics were calculated for all included patients. χ2 tests were used to compare categorical variables. P values < 0.05 were statistically significant.

RESULTS

A total of 45,542 procedures were conducted in the United States from 2010 to 2020 (clipping: 14,491; coiling: 28,840; flow diversion: 2211). The Southern United States had the largest operative volume across all 3 intervention types, closely followed by the Midwest. Aneurysms of the middle cerebral artery were mostly clipped, whereas coiling and flow diversion techniques were most utilized for anterior communicating and posterior communicating artery aneurysms. Flow diversion is growing most rapidly in the treatment of unruptured aneurysms, though there were also significant increases in usage for ruptured aneurysm treatment from 2019 to 2020.

CONCLUSIONS

Flow diverters have gained significant traction in the treatment for both unruptured and ruptured aneurysms. In the coming years, the indications and use of flow diversion will undoubtedly grow further, but excitement over their application should be tempered by the safety and efficacy data that continues to emerge.

Long-term outcomes of coils embolization for superior hypophyseal artery aneurysms

Objective

Superior hypophyseal artery (SHA) aneurysms are intradural, and their rupture can result in subarachnoid hemorrhage. Considering the related surgical difficulty and anatomical restrictions, endovascular treatment (EVT) is considered the most favorable modality for SHA aneurysms; however, the long-term outcomes of EVT have rarely been reported. The study assessed the incidence of and risk factors for recurrence of SHA aneurysms after EVT as well as the correlation factors for SHA aneurysm rupture.

Methods

We included 112 patients with SHA aneurysms treated with EVT at our facility between 2009 and 2020. Here, EVT included non-stent-assisted (simple or balloon-assisted) or stent-assisted coiling. Flow diverter was not included because it was barely used due to its high cost under our national insurance's limitation, and a high proportion of ruptured aneurysms in our series. Univariate and multivariate logistic regression was performed to evaluate the correlation factors for SHA aneurysm rupture, along with the incidence of and risk factors for post-EVT SHA aneurysm recurrence and re-treatment.

Results

In our patients, the mean angiographic follow-up period was 3.12 years. The presence of type IA or IB cavernous internal carotid artery (cICA) was strongly correlated with SHA aneurysm rupture. Recurrence occurred in 17 (13.4%) patients, of which only 1 (1.4%) patient had received stent-assisted coiling. All cases of recurrence were observed within 2 years after EVT. The multivariate logistic regression results showed that ruptured aneurysm and non-stent-assisted coiling were independent risk factors for aneurysm recurrence. Of the 17 cases of aneurysm recurrence, 9 (52.9%) received re-treatment. Moreover, aneurysm rupture was the only factor significantly correlated with re-treatment in multivariate logistic regression. No re-recurrence was observed when a recurrent aneurysm was treated with stent-assisted coiling.

Conclusion

Type I cICA was common factor for aneurysm rupture. Although flow-diverter treatment serves as another suitable technique that was not compared with, coils embolization was effective treatment modality for SHA aneurysms, leading to low recurrence and complication rates, especially with stent use. All cases of recurrence occurred within 2 years after EVT; they were strongly associated with prior aneurysm rupture. Further stent-assisted coiling was noticed to prevent re-recurrence.

Utility of flow diverters in treatment of acutely ruptured uncoilable aneurysms of the posterior circulation of the brain

PURPOSE

Aim of this study is to evaluate safety and efficacy of flow diverters (FDs) in treatment of acutely ruptured posterior circulation aneurysms MATERIALS AND METHODS: Databases of three participating institutions were retrospectively scanned for patients in whom FD placement was attempted for treatment of acutely ruptured vertebrobasilar aneurysms. An interval of 14 days or fewer between the latest ictus and treatment was used as inclusion criterion. Patients with dolichoectasia of vertebrobasilar arteries were excluded. If necessary, adjunctive techniques including coiling or stenting were utilized. Clinical outcomes were graded using mWFNS (modified World Federation of Neurosurgical Societies Scale) and mRS (modified Rankin Scale). Aneurysmal occlusion was defined as Raymond-Roy Class 1. Spearman's (ρ) test was used to assess the correlation between variables. Univariate and multivariate logistic regression were used to assess outcomes.

RESULTS

31 patients (25 women, mean age: 52.7 ± 15.2) harboring 32 aneurysms (16 non-saccular, mean size: 11.4 ± 7 mm) were included. Mean number of FDs used was 1.22 ± 0.42. In six cases, adjunctive coiling and in five cases, apposing stent placement were used. Overall mortality rate and procedure-related mortality rates were 22.5% (7/31) and 9.6% (3/31), respectively. At a mean imaging follow-up of 17.2 ± 12.6 months, total occlusion was achieved in 22 aneurysms (91.6%). Univariate analysis showed that mortality was positively correlated with vasospasm (ρ = 0.600, p < 0.05), higher mWFNS Scale (ρ = 0.685, p < 0.05), higher modified Fischer Score (ρ = 0.609, p < 0.05), higher mRS (ρ = 0.594, p < 0.05) on admission and negatively correlated with saccular morphology (ρ = -0.529, p < 0.05). Multivariate logistic regression identified mWFNS on admission as a significant predictor. (OR: 7.148, 95% CI 1.777-28.758, p: 0.01). Adjunctive coiling positively correlated with aneurysm occlusion. (ρ = 0.522, p < 0.05).

CONCLUSION

The procedure-related morbidity and mortality is not negligible. However, the risks and efficacy associated with FDs are acceptable, especially when adjunctive coiling is possible, given the lack of treatment alternatives.

Use of the Woven EndoBridge Device for Sidewall Aneurysms: Systematic Review and Meta-analysis

BACKGROUND

The Woven EndoBridge device was originally approved to treat intracranial wide-neck saccular bifurcation aneurysms. Recent studies have suggested its use for the treatment of sidewall intracranial aneurysms with variable success.

PURPOSE

Our aim was to evaluate the safety and efficacy of the Woven EndoBridge device for sidewall aneurysms using a meta-analysis of the literature.

DATA SOURCES

We performed a systematic review of all studies including patients treated with the Woven EndoBridge device for sidewall aneurysms from inception until May 2022 on Scopus, EMBASE, MEDLINE, the Web of Science, and the Cochrane Central Register of Controlled Trials.

STUDY SELECTION

Ten studies were selected, and 285 patients with 288 sidewall aneurysms were included.

DATA ANALYSIS

A random-effects meta-analysis of proportions using a generalized linear mixed model was performed as appropriate. Statistical heterogeneity across studies was assessed with I2 statistics.

DATA SYNTHESIS

The adequate occlusion rate at last follow-up was 89% (95% CI, 81%-94%; I2, = 0%), the composite safety outcome was 8% (95% CI, 3%-17%; I2 = 34%), and the mortality rate was 2% (95% CI, 1%-7%; I2 = 0%). Aneurysm width (OR = 0.5; P = .03) was the only significant predictor of complete occlusion.

LIMITATIONS

Given the level of evidence, our results should be interpreted cautiously until confirmation from larger prospective studies is obtained.

CONCLUSIONS

The initial evidence evaluating the use of the Woven EndoBridge device for the treatment of wide-neck sidewall intracranial aneurysms has demonstrated high rates of adequate occlusion with low procedural complications. Our findings favor the consideration of the Woven EndoBridge device as an option for the treatment of sidewall aneurysms.

Endovascular treatment of ruptured basilar artery trunk aneurysm in the acute period: risk factors for periprocedural complications

OBJECTIVES

Endovascular treatment (EVT) has become a popular option for the treatment of basilar artery (BA) trunk aneurysms because microsurgery of these lesions is difficult due to narrow surgical fields and perforating arteries or cranial nerves in the brainstem. The purpose of this study is to report our experiences using EVT for ruptured BA trunk aneurysms in the acute period and to evaluate the risk factors for periprocedural complications.

METHODS

From October 2004 to December 2020, a total of 27 consecutive patients with ruptured BA trunk aneurysms were treated with EVT. All patients met the following criteria: presence of ruptured BA trunk aneurysms and treatment with EVT for those aneurysms within 72 hours of rupture. The incidence of and risk factors for periprocedural complications were evaluated retrospectively.

RESULTS

Among the 27 patients, periprocedural complications occurred in 4 patients (14.8%); mass effect inducing cranial neuropathy due to brainstem compression in 1 (3.7%) and brainstem infarction in 3 (11.1%). Hemorrhagic complications did not occur within 30 days. Subacute or delayed thromboembolic complications were not observed during the follow-up period. Large/giant aneurysm (odds ratio [OR], 6.417; 95% confidence interval [CI], 1.732-18.031; P = 0.045) and stent-assisted coiling (OR, 4.145; 95% CI, 1.018-14.212; P = 0.031) remained independent risk factors for periprocedural complications based on multiple logistic regression analysis.

CONCLUSIONS

When performing stent-assisted coiling for ruptured large/giant BA trunk aneurysms, awareness of and caution regarding periprocedural complications, such as brainstem infarction caused by thromboembolism or brainstem compression due to mass effect, are necessary.

A Systematic Literature Review and Meta-Analysis of the Treatment of Ruptured Intracranial Aneurysms with Hydrophilic Polymer and Phosphorylcholine-Coated Flow Diverters Under Single Antiplatelet Therapy

OBJECTIVE

Flow diverters coated with antithrombogenic substances were recently introduced and have shown encouraging results in the preclinical setting. Our aim was to analyze their clinical application in patients with ruptured intracranial aneurysms using single antiplatelet therapy (SAPT).

METHODS

We performed a PRISMA-compliant systematic review and meta-analysis covering 3 major data bases until March 2022.Two reviewers independently reviewed clinical studies for eligibility.Random-effects analysis of proportions was used to pool safety outcomes (hemorrhagic, thrombembolic, and overall complications). Studies were tested for publication bias and heterogeneity.

RESULTS

Five studies reporting 43 patients with 46 aneurysms were identified. More than 1 stent was implanted in 16%, and additional coil embolization was performed in 53.8% of patients. SAPT with one of various acetylsalicylic acid regimens was used in 86%, altogether antiplatelet protocols were variable. The pooled risks of thromboembolic (23.9%; 95% confidence interval [CI], 9.6-47.9), hemorrhagic (9.4%; 95% CI, 3.6-22.6), and overall complications (28.3%; 95% CI, 12.4-52.5) were calculated in the absence of publication bias with low to moderate study heterogeneity measures. All complications occurred in patients under acetylsalicylic acid SAPT. Adequate aneurysm occlusion was described in 65.5% of patients.few retrospective observational studies with moderate heterogeneity, encompassing a limited number of patients treated with variable SAPT regimens.

CONCLUSIONS

Flow diversion for ruptured aneurysms under SAPT with coated stents is feasible. Although the risk of hemorrhagic complications was low, thromboembolic complications occurred in a significant number of patients, all under ASA SAPT.

Worldwide productivity and research trends of publications concerning stent application in acutely ruptured intracranial aneurysms: A bibliometric study

Background

Stenting is a common clinical practice to treat acutely ruptured intracranial aneurysm (RIA). Although multiple studies have demonstrated its long-term safety and effectiveness, there is currently a lack of bibliometric analysis on stent application in acutely RIA. This study sought to summarize the current status of research in this field and lay a foundation for further study.

Materials and methods

Related publications were searched in the Web of Science Core Collection (WoSCC) database. Data analysis and visualization were performed by R and CiteSpace software.

Results

A total of 275 publications published in English from 1997 to 2022 were included in this study. The growth of publications slowed down. The reference co-citation network identified 13 clusters with a significant network (Q = 0.7692) and convincing clustering (S = 0.9082). The research focus was acutely RIA and the application of stents during interventional procedures. The main trends of research were: (1) development of materials, and (2) safety of stent application in acutely RIA. The United States contributed the most articles, and Jianmin Liu was the most prolific author. Mayo Clinic was the leading institution in this field. Most articles were published in Interventional Neuroradiology.

Conclusions

This study analyzed the research trends, hotspots and frontiers of stent application in acutely RIA. It is our hope that the results obtained could provide useful information to researchers to get a clearer picture about their future research directions in this field.

A Meta-analysis: Cost Comparison of Flow Diversion and Coil Embolization for Intracranial Aneurysm

Background

Intracranial aneurysm serves as a prevalent cerebral disorder leading to the low-quality life and financial burden of the patients. Flow diversion and coil embolization have been confirmed as common therapeutic strategies for intracranial aneurysms. In this work, we identified and compared the cost between the flow diversion and coil embolization in the treatment of intracranial aneurysms in a meta-analysis.

Methods

We downloaded literatures that are published before Feb 2021 from Cochrane Library, Embase, and Pubmed using terms including “flow diversion”, “pipeline embolization device”, “coil embolization”, “coiling”, “Intracranial aneurysms”, and “Cerebral aneurysms”. The data were analyzed by STATA 15.1. Differences in treatment costs were determined by WMD (95% CI).

Results

A total of 1332 articles were included in the search of the limited terms, and 8 were selected after eliminating duplicate and unwanted studies. Our data indicated that the total cost of flow diversion for intracranial aneurysms is significantly lower than coil embolization (WMD = −4419.12, 95% CI: -6292.21 to -2546.03, p ≤ 0.001). In addition, we explored the retreatment hospitalization cost of flow diversion and coil embolization for intracranial aneurysms. We found that the retreatment hospitalization cost of flow diversion for intracranial aneurysms is significantly higher than coil embolization (WMD = 3203.85, 95% CI: 1904.60 to 4503.10, p ≤ 0.001).

Conclusion

We concluded that the total cost was lower, and the retreatment hospitalization costs of flow diversion were higher than coil embolization for the treatment of intracranial aneurysms. Our finding provides valuable insights into the application of flow diversion and coil embolization in intracranial aneurysm therapy. Flow diversion may be applied as a major treatment with the consideration of retreatment.

Comparative study of on-label versus off-label treatment of intracranial aneurysms with the Pipeline embolization device

OBJECTIVE

The Pipeline embolization device (PED) is widely used for the treatment of intracranial aneurysms, including in off-label applications. In this work, the authors compared the real-world efficacy and safety of PED use in on-label and off-label aneurysm treatments.

METHODS

Clinical and angiographic data of patients who underwent PED placement at a high-volume academic medical center were retrospectively obtained. Treatments were classified as on-label if they fell within the applications approved by the United States Food and Drug Administration as of 2021. Recorded outcomes included aneurysm occlusion, procedural complications, ischemic events, in-stent stenosis, intracranial hemorrhage, postprocedural functional status, and death.

RESULTS

In total, 416 aneurysms in 330 patients were treated with PED, comprising 256 aneurysms that received on-label treatments and 160 that received off-label treatments. The overall rate of complete aneurysm occlusion was 76.4% for on-label aneurysms and 75.6% for off-label aneurysms (p = 0.898). The risk of ischemic stroke in patients who underwent off-label treatments was 15.2%, which was higher than the 4.2% rate in patients who underwent on-label treatment (p = 0.003). All other clinical complications, procedural complications, and long-term functional status were comparable between the on-label and off-label groups.

CONCLUSIONS

In real-world practice, off-label use of PED is common and can achieve similar efficacy as on-label use. However, in aggregate, off-label use was found to carry an increased rate of ischemic complications. With judicious attention to safety and individual patient characteristics, these results highlight the scale and general feasibility of off-label PED use by experts.

Endovascular Therapy Versus Microsurgical Clipping of Ruptured Wide Neck Aneurysms (EVERRUN Registry): a multicenter, prospective propensity score analysis

OBJECTIVE

Randomized controlled trials have demonstrated the superiority of endovascular therapy (EVT) compared to microsurgery (MS) for ruptured aneurysms suitable for treatment or when therapy is broadly offered to all presenting aneurysms; however, wide neck aneurysms (WNAs) are a challenging subset that require more advanced techniques and warrant further investigation. Herein, the authors sought to investigate a prospective, multicenter WNA registry using rigorous outcome assessments and compare EVT and MS using propensity score analysis (PSA).

METHODS

Untreated, ruptured, saccular WNAs were included in the analysis. A WNA was defined as having a neck ≥ 4 mm or a dome/neck ratio (DNR) < 2. The primary outcome was the modified Rankin Scale (mRS) score at 1 year posttreatment, as assessed by blinded research nurses (good outcome: mRS scores 0-2) and compared using PSA.

RESULTS

The analysis included 87 ruptured aneurysms: 55 in the EVT cohort and 32 in the MS cohort. Demographics were similar in the two cohorts, including Hunt and Hess grade (p = 0.144) and modified Fisher grade (p = 0.475). WNA type inclusion criteria were similar in the two cohorts, with the most common type having a DNR < 2 (EVT 60.0% vs MS 62.5%). More anterior communicating artery aneurysms (27.3% vs 18.8%) and posterior circulation aneurysms (18.2% vs 0.0%) were treated with EVT, whereas more middle cerebral artery aneurysms were treated with MS (34.4% vs 18.2%, p = 0.025). Within the EVT cohort, 43.6% underwent stand-alone coiling, 50.9% balloon-assisted coiling, 3.6% stent-assisted coiling, and 1.8% flow diversion. The 1-year mRS score was assessed in 81 patients (93.1%), and the primary outcome demonstrated no increased risk for a poor outcome with MS compared to EVT (OR 0.43, 95% CI 0.13-1.45, p = 0.177). The durability of MS was higher, as evidenced by retreatment rates of 12.7% and 0% for EVT and MS, respectively (p = 0.04).

CONCLUSIONS

EVT and MS had similar clinical outcomes at 1 year following ruptured WNA treatment. Because of their challenging anatomy, WNAs may represent a population in which EVT's previously demonstrated superiority for ruptured aneurysm treatment is less relevant. Further investigation into the treatment of ruptured WNAs is warranted.

Silk Vista Baby flow diverter stent for ruptured intracranial aneurysms: a retrospective observational study

PURPOSE

Flow diversion changed the approach to complex intracranial aneurysms, leading to a widespread use and a rapid technological evolution. Indeed, indications continued to expand, including ruptured intracranial aneurysms in selected cases. Recently, new devices have been designed specifically to target smaller vessels. Therefore, we conducted a multicenter study to evaluate clinical outcome, complications, and occlusion rate of patients with ruptured aneurysms treated with new generation low profile Silk Vista Baby (SVB) flow diverter stent (FD).

METHODS

We performed a retrospective observational study on consecutive patients who underwent treatment with SVB for ruptured aneurysms at 12 Italian centers. Primary end point was favorable clinical outcome rate, defined as modified ranking score (mRS) of 0-2 at the 3 months. Secondary outcomes were complication rate, aneurysm re-rupture, and complete aneurysm occlusion at last radiological follow-up.

RESULTS

Twenty-five patients were included; at 3 months' follow-up, 19 patients (79.1%) had favorable clinical outcome (mRS 0-2). Three patients (12.5%) died during follow-up. In-stent thrombosis occurred in two cases (8.3%), managed with glycoprotein IIb/IIIA and intra-stent angioplasty, without clinical consequences. In 18 (85.7%) patients, complete occlusion at 3 months was demonstrated. No rebleeding occurred during follow-up. Presentation with unfavorable World Federation of Neurosurgical Societies grading system (WFNS) and posterior circulation location were both significantly correlated with unfavorable clinical outcome (p = 0.005 and p = 0.02).

CONCLUSIONS

Our data suggests that low profile FD treatment of ruptured intracranial aneurysms located distally of the circle of Willis is feasible. New generation low profile FD may represent an alternative option in carefully selected cases.

Use of intravenous cangrelor in the treatment of ruptured and unruptured cerebral aneurysms: an updated single-center analysis and pooled analysis of current studies

BACKGROUND

Intracranial stent placement for the treatment of cerebral aneurysms is increasingly utilized in both ruptured and unruptured scenarios. Intravenous (IV) cangrelor is a relatively new antiplatelet agent that was initially approved for coronary interventions. In addition to our institution, five other centers have published their results using IV cangrelor in neurointerventional procedures. This article combines the aneurysm treatment data from all prior studies to provide insight into the safety and efficacy of cangrelor for intracranial aneurysm treatment.

METHODS

A prospectively maintained database was reviewed to identify all cases of IV cangrelor administration during aneurysm embolization. 20 additional patients were identified who had not been previously published. In addition, a literature search was performed to identify prior publications regarding cangrelor in neurointervention. The data from these were combined with our institutional results in a pooled-analysis.

RESULTS

Overall, 85 patients who received IV cangrelor during aneurysm embolization were identified, including 46 ruptured and 39 unruptured cases. The asymptomatic and symptomatic intracranial hemorrhage rates were 4% (2/46) for ruptured cases and 2.6% (1/39) for unruptured cases. The rate of retroperitoneal hematoma and gastrointestinal bleeding was 0%. There were no incidents of intraprocedural thromboembolic complication or intraprocedural in-stent thrombosis in either cohort. One subject suffered an ischemic stroke at 24 hours secondary to in-stent thrombosis in a ruptured case.

CONCLUSIONS

IV cangrelor during aneurysm embolization appears to be safe, with a symptomatic intracranial hemorrhage rate of 4% in ruptured cases and 2.6% in unruptured cases. More research is needed to determine the ideal dosing regimen.

The Safety and Efficacy of Flow Diversion versus Conventional Endovascular Treatment for Intracranial Aneurysms: A Meta-analysis of Real-world Cohort Studies from the Past 10 Years

BACKGROUND

Although the flow diverter has advantages in the treatment of intracranial aneurysms, pooled studies that directly compare it with conventional endovascular treatments are rare.

PURPOSE

Our aim was to compare the safety and efficacy of flow-diverter and conventional endovascular treatments in intracranial aneurysms.

DATA SOURCES

We performed a comprehensive search of the literature using PubMed, EMBASE, and the Cochrane Database.

STUDY SELECTION

We included only studies that directly compared the angiographic and clinical outcomes of flow-diverter and conventional endovascular treatments.

DATA ANALYSIS

Random effects or fixed effects meta-analysis was used to pool the cumulative rate of short- and long-term angiographic and clinical outcomes.

DATA SYNTHESIS

Eighteen studies with 1001 patients with flow diverters and 1133 patients with conventional endovascular treatments were included; 1015 and 1201 aneurysm procedures were performed, respectively. The flow-diverter group had aneurysms of a larger size (standard mean difference, 0.22; 95% CI, 0.03-0.41; P = .026). There was a higher risk of complications in the flow-diverter group compared with the conventional endovascular group (OR, 1.4; 95% CI, 1.01-1.96; P = .045) during procedures. The follow-up angiographic results of flow-diverter treatment indicated a higher rate of complete occlusion (OR, 2.55; 95% CI, 1.70-3.83; P < .001) and lower rates of recurrence (OR, 0.24; 95% CI, 0.12-0.46; P < .001) and retreatment (OR, 0.31; 95% CI, 0.21-0.47; P < .001).

LIMITATIONS

Limitations include a retrospective, observational design in some studies, high heterogeneity, and selection bias.

CONCLUSIONS

Compared with the conventional endovascular treatments, the placement of a flow diverter may lead to more procedure-related complications, but there is no difference in safety, and it is more effective in the long term.

Computed Tomography Perfusion Imaging Study of Intracranial Complex Aneurysms Treated by Internal Maxillary Artery Bypass Grafting

BACKGROUND

Cerebral revascularization strategies through extracranial to intracranial bypass have been adopted in the management of complex intracranial aneurysms. The internal maxillary artery used as a donor in a bypass is an effective method. At present, there are few quantitative analyses of cerebral blood flow perfusion. The main focus of this study was to evaluate the effectiveness of blood perfusion after bypass grafting.

METHODS

From April 2015 to December 2017, 19 patients who underwent internal maxillary artery radial artery middle cerebral artery bypass surgery with unobstructed bypass vessels were selected. Cerebral blood flow perfusion before and after bypass surgery was quantitatively evaluated by computed tomography perfusion imaging. The cerebral blood perfusion in the region of interest was measured by computed tomography perfusion.

RESULTS

The aneurysms were excised after trapping in 2 cases with mass effects and neural compression. Proximal occlusion of the parent artery was performed in 9 cases of fusiform or giant dissecting aneurysms. Trapping was performed after bypass surgery in 8 cases. Within 3 months after surgery, 17 patients had good outcomes. After the hypothesis test, there was a significant difference between the preoperative △cerebral blood volume and postoperative △cerebral blood volume in the anterior area of the semioval center cross section (P = 0.001 < 0.05).

CONCLUSIONS

The internal maxillary artery as a bypass donor is an effective method that can provide sufficient intracranial blood perfusion, and there is usually no cerebral ischemia in the surrounding area.

Timing and outcome of bystanders treatment in patients with subarachnoid hemorrhage associated with multiple aneurysms

In case of subarachnoid hemorrhage (SAH) associated with multiple intracranial aneurysms (MIAs), the main goal of acute treatment is securing the source of bleeding (index aneurysm). Indications and timing of bystanders treatment are instead still debated as the risk of new SAHs in patients harboring MIAs is not yet established. However, even if technically feasible, a simultaneous management of all aneurysms remains questionable, especially for safety issues. We retrospectively reviewed our last 5-year experience with SAH patients harboring MIAs entered in a clinic-radiological monitoring for bystanders follow-up in order to evaluate the occurrence of morphological changes, bleeding events, and safety and efficacy of a delayed treatment. We included 39 patients with mean age of 59.5 ± 12.2 years who survived a SAH. Among them, 14 underwent treatment, whereas 25 continued follow-up. The mean time between index and bystanders treatment was 14.3 ± 19.2 months. Patients undergoing bystanders treatment were mainly female and in general younger than patients undergoing observation. No cases of growth or bleeding were observed among bystanders within the two groups during the follow-up, which was longer than 1 year for the intervention group, and almost 40 months for the observation group. No major complications and mRS modifications were observed after bystanders treatment. Our data seem to suggest that within the short follow-up, intervention and observation seem to be likewise safe for bystander aneurysms, showing at the same time that a delayed management presents a similar risk profile of treating unruptured aneurysms in patients with no previous history of SAH.

Outcomes after Flow Diverter Treatment in Subarachnoid Hemorrhage: A Meta-Analysis and Development of a Clinical Prediction Model (OUTFLOW)

Background: patients with a subarachnoid hemorrhage (SAH) might need a flow diverter (FD) placement for complex acutely ruptured intracranial aneurysms (IAs). We conducted a meta-analysis and developed a prediction model to estimate the favorable clinical outcome after the FD treatment in acutely ruptured IAs. Methods: a systematic literature search was performed from 2010 to January 2021 in PubMed and Embase databases. Studies with more than five patients treated with FDs within fifteen days were included. In total, 1157 studies were identified. The primary outcome measure was the favorable clinical outcome (mRS 0–2). Secondary outcome measures were complete occlusion rates, aneurysm rebleeding, permanent neurologic deficit caused by procedure-related complications, and all-cause mortality. A prediction model was constructed using individual patient-level data. Results: 26 retrospective studies with 357 patients and 368 aneurysms were included. The pooled rates of the favorable clinical outcome, mortality, and complete aneurysm occlusion were 73.7% (95% CI 64.7–81.0), 17.1% (95% CI 13.3–21.8), and 85.6% (95% CI 80.4–89.6), respectively. Rebleeding occurred in 3% of aneurysms (11/368). The c-statistic of the final model was 0.83 (95% CI 0.76–0.89). All the studies provided a very low quality of evidence. Conclusions: FD treatment can be considered for complex ruptured IAs. Despite high complication rates, the pooled clinical outcomes seem favorable. The prediction model needs to be validated by larger prospective studies before clinical application.

Effect of flow diverter stent malposition on intracranial aneurysm hemodynamics—An experimental framework using stereoscopic particle image velocimetry

Background

Flow-diverting stents are increasingly used for the minimally-invasive treatment of intracranial aneurysms. However, a correct positioning of such devices can be challenging due to varying vessel diameters as well as the complex anatomy of the neurovasculature. As a consequence, unsuccessful treatment outcomes are increasingly reported requiring an improvement of the understanding of stent-induced flow modification.

Methods

To evaluate the effect of different degrees of flow diverter stent malposition on intra-aneurysmal hemodynamic changes, a controlled hemodynamic configuration was created using an idealized intracranial aneurysms model. Afterwards, four different treatment scenarios were reproduced comprising of 1) the ideal treatment, 2) an insufficient wall apposition in the region of the ostium, 3) a distorted device migrating into the aneurysm sac and 4) an inaccurately deployed stent due to wrong release location. For the assessment of the individual flow modifications, high-resolution stereoscopic particle image velocimetry (PIV) measurements were carried out.

Results

The analysis of the precise in-vitro PIV measurements reveals that in all cases a considerable reduction of the cycle-averaged and peak-systolic velocity was obtained. Compared to the untreated aneurysm configuration, the flow reduction ranged from 63% (scenario 4) up to 89% (scenario 3). The ideal treatment reached a reduction of 78%, which is known to be sufficient for a successful therapy. However, inaccurate device positioning leads to increased oscillating flow towards the lateral directions reducing the chances of sufficient thrombus formation.

Conclusions

High-resolution in-vitro PIV measurements enable an accurate quantification of the treatment efficacy for flow-diverting devices. Furthermore, insufficient treatment outcomes can be reproduces allowing for an assessment of intra-aneurysmal hemodynamic changes.

A giant basilar artery perforator aneurysm

Basilar artery perforator aneurysms (BAPA's) are a rare entity. Their natural history and treatment are unclear. We describe the largest BAPA reported thus far in literature in a 64-year-old Caucasian woman. This patient did not present with subarachnoid hemorrhage, but with left hemiparesis due to pontine ischemia. The aneurysm was initially misdiagnosed as a tumoral mass in a referring center. Angiography confirmed the presence of a BAPA and a flow diverter was successfully placed. This case shows us that a BAPA can mimic a tumoral mass and can cause ischemia due to mass effect without having ruptured. Both conservative and flow diverter placement seems viable treatment options. Individual patient characteristics and preferences should be considered in decision-making for treatment.

A systematic review and meta-analysis of the Derivo Embolization Device: a novel surface-modified flow diverter for intracranial aneurysm treatment

BACKGROUND

Surface-modified flow diverters (FDs) designed to reduce thrombogenicity represent the next frontier for intracranial aneurysm treatment. The Derivo Embolization Device (DED) is a novel FD with titanium oxide and titanium oxynitride finishing of the struts. We performed a systematic review of pertinent literature, aiming to evaluate the device's effectiveness and safety.

METHODS

A literature search of PubMed, Embase, and MEDLINE was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Five studies comprising 481 aneurysms were included. These studies were conducted in Turkey, Brazil, Germany, Poland, and Italy; two were prospective and three were retrospective. Twenty-six aneurysms (5.4%) were ruptured. The antiplatelet regimens were heterogeneous, but dual antiplatelet therapy was administered preprocedurally in all studies and maintained for 3-12 months before a switch to single antiplatelet therapy. The rate of periprocedural ischemic and hemorrhagic complications was 4.9% (95% CI 2.9% to 7%). Adjunctive coiling was used in 25.6% (95% CI 11.4% to 39.8%) of aneurysms. The complete angiographic occlusion rate was 81.4% (95% CI 71.3% to 91.5%), mortality rate was 2.1% (95% CI 0.4% to 3.9%), with follow-up ranging from 9 to 18 months. Delayed aneurysm rupture was reported in one patient.

CONCLUSIONS

The DED has been increasingly used in other countries. We identified low rates of periprocedural complications and mortality and a high rate of complete occlusion.

Flow Diverter Treatment of Ruptured Basilar Artery Perforator Aneurysms

Purpose

Ruptured basilar artery perforator aneurysms (BAPAs) represent a very rare cause of subarachnoid hemorrhage and an under-reported subtype of cerebral aneurysm. There is no consensus for the optimal treatment strategy (conservative vs. surgical vs. various endovascular approaches). We aim to present a multicenter experience of BAPA treatment using flow-diverter (FD) stents.

Methods

At five tertiary neurovascular centers, all cases of ruptured BAPAs treated by FD were retrospectively collected. Baseline imaging and clinical characteristics, complications, as well as early and long-term angiographic and clinical outcome (mRS) were analyzed.

Results

Eighteen patients (mean age, 57 years; SD, ±10.7 years) with acute SAH related to a BAPA were treated using 18 FD stents. Aneurysms were detected on initial imaging study in 28%; delayed diagnosis was triggered by clinical deterioration due to rebleeding in 15%. No rebleeding after FD was seen, 28% developed FD-related ischemic complications. At long term (n = 16), overall mortality was 13% (2/16), and favorable outcome (mRS 0–2) was 81% (13/16). All BAPAs (n = 13) were completely occluded at long-term angiographic follow-up.

Conclusion

In our multicenter experience, FD treatment of ruptured BAPAs appears to have comparable safety and efficacy outcomes to FD treatment of other ruptured posterior circulation aneurysms as well as to the conservative management of BAPAs. This treatment strategy for a ruptured BAPA achieved a high rate of angiographic occlusion and favorable clinical outcome; however, as the conservative management also seems to offer similar clinical outcomes an individualized treatment decision is warranted. Future prospective studies comparing both approaches are required.

Supplementary Information

The online version of this article (10.1007/s00062-021-01133-y) contains supplementary material, which is available to authorized users.

Flow diversion for acutely ruptured intracranial aneurysms treatment: A retrospective study and literature review

OBJECTIVE

Flow diversion is becoming an increasingly established practice for the treatment of acutely ruptured intracranial aneurysms. In this study the authors present a literature review and meta-analysis, adding a retrospective review of institutional registry on emergency treatment of aRIA with flow diverter stent.

MATERIALS AND METHODS

A systematic search of PubMed, SCOPUS, Ovid MEDLINE, and Ovid EMBASE was performed on April 20^th, 2021, extrapolating 35 articles. R language 'meta' and 'metafor' packages were used for data pooling. The DerSimonian-Laird model was used to calculate the pooled effect. The I² value and Q statistic evaluated study heterogeneity. Additionally, the authors retrospectively reviewed their institutional database for the treatment and outcomes of all patients with acutely ruptured intracranial aneurysms treated with flow diverter stent placement from May 2010 to November 2020 was performed.

RESULTS

From the systematic literature review and meta-analysis, the pooled proportion of complete aneurysm occlusion was 78%, with a pooled rate of 79%, 71%, 80%, and 50% for dissecting, saccular, fusiform, and mycotic aneurysms, respectively. The pooled proportion of aneurysm rebleeding and intrastent stenosis was 12% and 15% respectively, for a total of 27% rate. The analysis of authors retrospective register showed an overall mortality rate of 16.7% (3/18), with a low but not negligible postprocedural rebleeding and intrastent thrombosis rates (5.6% and 11.1% respectively).

CONCLUSION

Although increasingly utilized in the management of selected patients with acutely ruptured intracranial aneurysms, flow diversion for acutely ruptured intracranial aneurysms treatment presents rebleeding and intrastent stenosis rates not negligible.

Endovascular Management of Hemorrhagic Stroke

Significant advances in endovascular neurosurgery tools, devices, and techniques are changing the approach to the management of acute hemorrhagic stroke. The endovascular treatment of intracranial aneurysms emerged in the early 1990s with Guglielmi detachable coils, and since then, it gained rapid popularity that surpassed open surgery. Stent-assisted coiling and balloon remodeling techniques have made the treatment of wide-necked aneurysms more durable. With the introduction of flow diverters and flow disrupters, many aneurysms with complex geometrics can now be reliably managed. Arteriovenous malformations and fistulae can also benefit from endovascular therapy by embolization using n-butyl cyanoacrylate (NBCA), Onyx, polyvinyl alcohol (PVA), and coils. In this article, we describe the role of endovascular treatment for the most common causes of intracerebral and subarachnoid hemorrhages, particularly ruptured aneurysms and vascular malformations.

Comprehensive review of the recent advances in devices for endovascular treatment of complex brain aneurysms

The International Subarachnoid Aneurysm Trial (ISAT) showed superiority for endovascular treatment of ruptured aneurysms and technology has since moved on rapidly. Many approaches and technology now exist for the endovascular management of ruptured and unruptured intracranial aneurysms, which reflects their varied nature - there is no one-size-fits-all technique. We aim to provide an overview of the various classes of device and the major developments over the past decade. Coiling is the oldest of the technology and continues to demonstrate high levels of occlusion and acceptable risks, making it the default treatment choice, particularly in the acutely ruptured aneurysm setting. Advances on coiling include the use of adjuncts such as balloons, stents and fully retrievable temporary neck-bridging devices, which have facilitated the treatment of more complex aneurysms. Flow divertors have also revolutionised complex aneurysm treatment with small added risk in acute aneurysm treatment and seek to remodel the aneurysm-vessel interface without accessing the aneurysm sac. The latest development and most promising avenue appears to be intrasaccular flow disrupting devices like WEB, Contour and Neqstent that provide excellent opportunities to treat wide neck complex aneurysm with minimal mortality and morbidity and good occlusion rates and may in future replace a significant number of stent-assisted coiling too.

Isolated clival subdural haemorrhage from a dolicoectactic vertebrobasilar aneurysm: Case report and overview of endovascular treatment strategies

Posterior fossa aneurysms presenting with isolated subdural haemorrhage (SDH) have scarcely been described with no cases attributed to a vertebrobasilar (VB) location. Non-saccular VB aneurysms are a distinct sub-group and in this report we also discuss the pathophysiology and treatment options for these difficult-to-manage lesions. We present a case of a 49 year-old man who presented with a 7-day history of severe headaches who was found to have an isolated acute clival SDH. Vascular imaging revealed a VB dolicoectatic segment with superimposed fusiform dilatations that contacted the dura adjacent to the SDH. A staged treatment was performed with initial parental vessel occlusion of the ruptured vertebral artery segment and subsequent insertion of a braided stent (LEO) with flow diverting properties into the progressively dilating basilar artery. A third procedure was performed to occlude a recurrent pouch at the lower basilar dilatation. Complete angiographic occlusion was achieved and the patient is under continued surveillance. To our knowledge, this is the first case of a ruptured non-saccular VB aneurysm presenting with radiologically isolated clival SDH. Clinical history will often inform the need for vascular imaging in such atypical presentations. Managing these lesions remains an endovascular challenge and requires a specialist multi-disciplinary approach.

Flow Diversion for Middle Cerebral Artery Aneurysms: An International Cohort Study

BACKGROUND

Open surgery has traditionally been preferred for the management of bifurcation middle cerebral artery (MCA) aneurysms. Flow diverting stents present a novel endovascular strategy for aneurysm treatment.

OBJECTIVE

To add to the limited literature describing the outcomes and complications in the use of flow diverters for the treatment of these complex aneurysms.

METHODS

This is a multicenter retrospective review of MCA bifurcation aneurysms undergoing flow diversion. We assessed post-treatment radiological outcomes and both thromboembolic and hemorrhagic complications.

RESULTS

We reviewed the outcomes of 54 aneurysms treated with flow diversion. Four (7.4%) of the aneurysms had a history of rupture (3 remote and 1 acute). Fourteen (25.9%) of the aneurysms already underwent either open surgery or coiling prior to flow diversion. A total of 36 out of the 45 aneurysms (80%) with available follow-up data had adequate aneurysm occlusion with a median follow-up time of 12 mo. There were no hemorrhagic complications but 16.7% (9/54) had thromboembolic complications.

CONCLUSION

Flow diverting stents may be a viable option for the endovascular treatment of complex bifurcation MCA aneurysms. However, compared to published series on the open surgical treatment of this subset of aneurysms, flow diversion has inferior outcomes and are associated with a higher rate of complications.

Flow-diverter stents in the early management of acutely ruptured brain aneurysms: effective rebleeding protection with low thromboembolic complications

OBJECTIVE

Flow-diverter stents (FDSs) are not generally used for the management of acutely ruptured aneurysms with associated subarachnoid hemorrhage (SAH). Herein, the authors present their experience with FDSs in this scenario, focusing on the antiplatelet regimen, perioperative management, and outcome.

METHODS

The authors retrospectively reviewed their institutional database for the treatment and outcomes of all patients with acutely ruptured aneurysms and associated SAH from July 2010 to September 2018 who had received an FDS implant as stand-alone treatment within 4 days after diagnosis. The protocol with the use of flow diversion in these patients includes a low threshold for placement of external ventricular drains before stenting, followed by the administration of aspirin and clopidogrel with platelet testing before stent implantation. With this approach, the risk of hemorrhage and stent-related thrombus formation is limited. Demographic, clinical, technical, and imaging data were analyzed.

RESULTS

Overall, 76 patients (61% females, mean age 42.8 ± 11.3 years) met the inclusion criteria. FDS implantation was performed a median of 2 days after diagnosis. On average, 1.05 devices were used per procedure. There was no procedural mortality directly attributed to the endovascular intervention. Procedural device-related clinical complications were recorded in a total of 6 cases (7.9%) and resulted in permanent neurological morbidity in 2 cases (2.6%). There was complete immediate aneurysm occlusion in 11 patients (14.5%), and persistent aneurysm filling was seen in 65 patients (85.5%). Despite this, no patient presented with rebleeding from the target aneurysm. There was an excellent clinical outcome in 62 patients (81.6%), who had a 90-day modified Rankin Scale score of 0-2. Among the 71 survivors, total or near-total occlusion was observed in 64/67 patients (95.5%) with a 3- to 6-month angiographic follow-up and in all cases evaluated at 12 months. Five patients (6.6%) died during follow-up for reasons unrelated to the procedure or new hemorrhage.

CONCLUSIONS

Flow diversion is an effective therapeutic strategy for the management of select acutely ruptured aneurysms. Despite low rates of immediate aneurysm occlusion after FDS implantation, the device exerts an important protective effect. The authors' experience confirmed no aneurysm rerupture, high rates of delayed complete occlusion, and complication rates that compare favorably with the rates obtained using other techniques.

Early Treatment of Ruptured Blood Blister-Like Aneurysms of the Internal Carotid Artery With Flow Diverters Using Single Antiplatelet Therapy: A Single-Center Experience With Long-Term Follow-Up

Background and Purpose: Blood Blister-like aneurysms (BBAs) of the internal carotid artery (ICA) are rare entities of cerebral aneurysms. FD use in acutely ruptured aneurysms, timing of treatment and antiplatelet regimen are main debate topics in clinical practice when the treatment decision is flow diversion. The aim of this study is to report the safety and efficacy of a single-center FD treatment for ruptured BBAs in the early phase of SAH using the SAPT regimen.

Material and Method: This study involved a retrospective analysis of a prospectively collected database. Records of patients admitted to our clinic and treated by endovascular route on ruptured BBA between January 2013 and December 2020 were reviewed. Ruptured supraclinoid ICA BBAs treated with FD devices with SAPT within 48 h from ictus of SAH are included. BBA of atypical anatomic locations, other endovascular techniques performed, and delayed admissions (>48 h) were excluded from the study. Demographic, clinical and angiographic features of patients and aneurysms, FD types and numbers, periprocedural complications, immediate and follow-up angiographic and clinical outcomes were recorded.

Results: A total of six patients with ruptured BBAs treated via FDs within 48 h and used SAPT were included in the study. The mean age was 41.6 years (range from 34 to 45 years), and four of six patients were female. All patients were treated within 48 h after ictus, and the mean treatment day was 1.33 days. One patient received ticagrelor, and five patients received prasugrel as SAPT for one year after treatment. No procedure-related death and rebleeding were recorded. One (16.7 %) treatment responsive procedure-related complication occurred (transient ischemia). Overall good outcome rate was 83.3%. One patient died due to pneumonia. The immediate control angiograms showed complete occlusions of BBAs in one patient (16.6%). The complete occlusion rate was 100 % for five survivors at the control angiogram. The median follow-up was 49.5 months.

Conclusion: This single-center experience suggests that early treatment (<2 days) within SAH of ruptured BBAs with FDs using SAPT is safe and effective in terms of clinical and radiological long-term outcomes.

Pipeline Embolization Device for the Treatment of Ruptured Intracerebral Aneurysms: A Multicenter Retrospective Study

Background and Purpose: The utilization of flow diversion for ruptured intracerebral aneurysms (IAs) is still limited. We aimed to demonstrate our multicenter experience using the pipeline embolization device (PED) for ruptured IAs that were difficult to treat by clipping and coiling.

Methods: Thirty-eight patients with ruptured IAs who underwent PED treatment from 2015 to 2020 were retrospectively reviewed. Factors associated with procedure-related stroke (ischemic and hemorrhagic) and clinical and angiography outcomes were analyzed.

Results: There were 14 (36.8%) saccular IAs, 12 (31.6%) blister-like IAs, and 12 (31.6%) dissecting IAs. Perforator involvement was noted in 10 (26.3%) IAs. Early PED placement ( ≤ 15 days) and adjunctive coiling treatment were performed in 27 (71.1%) and 22 (57.9%) cases, respectively. The overall rate of stroke-related complications was 31.6% (12/38) (including rates of 10.5% for procedure-related hemorrhagic complications and 15.8% for procedure-related infarction). The mortality rate was 13.2% (5/38), and 84.2% of patients (32/38) had favorable outcomes. Thirty-two (84.2%) patients underwent follow-up angiographic evaluations; of these, 84.4% (27 patients) had complete occlusion and 15.6% had incomplete obliteration. Multivariate analysis revealed that early PED placement was not associated with a high risk of procedure-related stroke or an unfavorable outcome. Adjunctive coiling exhibited an association with procedure-related stroke (p = 0.073). Procedure-related hemorrhagic complications were significantly associated with an unfavorable outcome (p = 0.003). Immediate contrast stasis in the venous phase was associated with complete occlusion during follow-up (p = 0.050).

Conclusion: The PED is a feasible and effective treatment to prevent rebleeding and achieve aneurysm occlusion, but it is associated with a substantial risk of periprocedural hemorrhage and ischemic complications in acute ruptured IAs. Therefore, the PED should be used selectively for acutely ruptured IAs. Additionally, adjunctive coiling might increase procedure-related stroke; however, it may reduce aneurysm rebleeding in acutely ruptured IAs. Patients with immediate contrast stasis in the venous phase were more likely to achieve total occlusion. A prospective study with a larger sample size should be performed to verify our results.

First Experience of Three Neurovascular Centers With the p64MW-HPC, a Low-Profile Flow Diverter Designed for Proximal Cerebral Vessels With Antithrombotic Coating

Background: In the last decade, flow diversion (FD) has been established as hemodynamic treatment for cerebral aneurysms arising from proximal and distal cerebral arteries. However, two significant limitations remain—the need for 0.027” microcatheters required for delivery of most flow diverting stents (FDS), and long-term dual anti-platelet therapy (DAPT) in order to prevent FDS-associated thromboembolism, at the cost of increasing the risk for hemorrhage. This study reports the experience of three neurovascular centers with the p64MW-HPC, a FDS with anti-thrombotic coating that is implantable via a 0.021” microcatheter.

Materials and methods: Three neurovascular centers contributed to this retrospective analysis of patients that had been treated with the p64MW-HPC between March 2020 and March 2021. Clinical data, aneurysm characteristics, and follow-up results, including procedural and post-procedural complications, were recorded. The hemodynamic effect was assessed using the O'Kelly–Marotta Scale (OKM).

Results: Thirty-two patients (22 female, mean age 57.1 years) with 33 aneurysms (27 anterior circulation and six posterior circulation) were successfully treated with the p64MW-HPC. In 30/32 patients (93.75%), aneurysmal perfusion was significantly reduced immediately post implantation. Follow-up imaging was available for 23 aneurysms. Delayed aneurysm perfusion (OKM A3: 8.7%), reduction in aneurysm size (OKM B1-3: 26.1%), or sufficient separation from the parent vessel (OKM C1-3 and D1: 65.2%) was demonstrated at the last available follow-up after a mean of 5.9 months. In two cases, device thrombosis after early discontinuation of DAPT occurred. One delayed rupture caused a caroticocavernous fistula. The complications were treated sufficiently and all patients recovered without permanent significant morbidity.

Conclusion: Treatment with the p64MW-HPC is safe and feasible and achieves good early aneurysm occlusion rates in the proximal intracranial circulation, which are comparable to those of well-established FDS. Sudden interruption of DAPT in the early post-interventional phase can cause in-stent thrombosis despite the HPC surface modification. Deliverability via the 0.021” microcatheter facilitates treatment in challenging vascular anatomies.