Advances in Embolization of bAVMs.

Brain AVMs are complex malformations, usually congenital, that need a deep understanding of anatomy and pathophysiology to be safely treated. Nowadays, embolization and radiosurgery are carried out more frequently due to their reduced invasiveness as compared to conventional neurosurgery. This paper aims to describe different and new endovascular approaches that allow the interventionalist to treat almost all the small AVMs and to reduce the nidus of the bigger ones in order to facilitate the surgical or radiosurgical intervention.

Learning Curve for Flow Diversion of Posterior Circulation Aneurysms: A Long-Term International Multicenter Cohort Study.

BACKGROUND AND PURPOSE: Flow diversion has gradually become a standard treatment for intracranial aneurysms of the anterior circulation. Recently, the off-label use of the flow diverters to treat posterior circulation aneurysms has also increased despite initial concerns of rupture and the suboptimal results. This study aimed to explore the change in complication rates and treatment outcomes across time for posterior circulation aneurysms treated using flow diversion and to further evaluate the mechanisms and variables that could potentially explain the change and outcomes. MATERIALS AND METHODS: A retrospective review using a standardized data set at multiple international academic institutions was performed to identify patients with ruptured and unruptured posterior circulation aneurysms treated with flow diversion during a decade spanning January 2011 to January 2020. This period was then categorized into 4 intervals. RESULTS: A total of 378 procedures were performed during the study period. Across time, there was an increasing tendency to treat more vertebral artery and fewer large vertebrobasilar aneurysms (P = .05). Moreover, interventionalists have been increasingly using fewer overlapping flow diverters per aneurysm (P = .07). There was a trend toward a decrease in the rate of thromboembolic complications from 15.8% in 2011-13 to 8.9% in 2018-19 (P = .34). CONCLUSIONS: This multicenter experience revealed a trend toward treating fewer basilar aneurysms, smaller aneurysms, and increased usage of a single flow diverter, leading to a decrease in the rate of thromboembolic and hemorrhagic complications.

Posterior Circulation Endovascular Thrombectomy for Large-Vessel Occlusion: Predictors of Favorable Clinical Outcome and Analysis of First-Pass Effect.

BACKGROUND AND PURPOSE: Successful vessel recanalization in posterior circulation large-vessel occlusion is considered crucial, though the evidence of clinical usefulness, compared with the anterior circulation, is not still determined. The aim of this study was to evaluate predictors of favorable clinical outcome and to analyze the effect of first-pass thrombectomy. MATERIALS AND METHODS: A retrospective, multicenter, observational study was conducted in 10 high-volume stroke centers in Europe, including the period from January 2016 to July 2019. Only patients with an acute basilar artery occlusion or a single, dominant vertebral artery occlusion ("functional" basilar artery occlusion) who had a 3-month mRS were included. Clinical, procedural, and radiologic data were evaluated, and the association between these parameters and both the functional outcome and the first-pass effect was assessed. RESULTS: A total of 191 patients were included. A lower baseline NIHSS score (adjusted OR, 0.77; 95% CI, 0.61-0.96; P = .025) and higher baseline MR imaging posterior circulation ASPECTS (adjusted OR, 3.01; 95% CI, 1.03-8.76; P = .043) were predictors of better outcomes. The use of large-bore catheters (adjusted OR, 2.25; 95% CI, 1.08-4.67; P = .030) was a positive predictor of successful reperfusion at first-pass, while the use of a combined technique was a negative predictor (adjusted OR, 0.26; 95% CI, 0.09-0.76; P = .014). CONCLUSIONS: The analysis of our retrospective series demonstrates that a lower baseline NIHSS score and a higher MR imaging posterior circulation ASPECTS were predictors of good clinical outcome. The use of large-bore catheters was a positive predictor of first-pass modified TICI 2b/3; the use of a combined technique was a negative predictor.

Flow-Diversion Treatment of Unruptured Saccular Anterior Communicating Artery Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND: Flow diversion for anterior communicating artery aneurysms required further investigation. PURPOSE: Our aim was to analyze outcomes after treatment of anterior communicating artery aneurysms with flow-diverter stents. DATA SOURCES: A systematic search of 3 data bases was performed for studies published from 2008 to 2018. STUDY SELECTION: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting anterior communicating artery aneurysms treated with flow diversion. DATA ANALYSIS: Random-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, and factors influencing the studied outcomes. DATA SYNTHESIS: We included 14 studies and 148 unruptured saccular anterior communicating artery aneurysms treated with flow diversion. The long-term complete/near-complete (O'Kelly-Marotta C-D) occlusion rate was 87.4% (91/105; 95% CI, 81.3%-93.6%; I2 = 0%) (mean radiologic follow-up of 11 months). The treatment-related complication rate was 8.6% (14/126; 95% CI, 4%-13.1%; I2 = 0%), with morbidity and mortality rates of 3.5% (5/126; 95% CI, 2%-7%; I2 = 0%) and 2.5% (2/148; 95% CI, 0.3%-5%; I2 = 0%), respectively. Most complications were periprocedural (12/126 = 7%; 95% CI, 3%-11%; I2 = 0%). Thromboembolic events were slightly higher compared with hemorrhagic complications (10/126 = 6%; 95% CI, 2%-10%; I2 = 0% and 4/126 = 3%; 95% CI, 1%-6%; I2 = 0%). Branching arteries (A2 or the recurrent artery of Heubner) covered by the stent were occluded in 16% (7/34; 95% CI, 3.5%-28%; I2 = 25%) of cases. Pre- and posttreatment low-dose and high-dose of antiplatelet therapy was not associated with significantly different complication and occlusion rates. LIMITATIONS: We reviewed small and retrospective series. CONCLUSIONS: Flow diversion for unruptured saccular anterior communicating artery aneurysms appears to be an effective alternative treatment for lesions difficult to treat with coiling or microsurgical clipping. The treatment-related complication rate was relatively low. However, larger studies are needed to confirm these results.

Y-Stent-Assisted Coiling of Wide-Neck Bifurcation Intracranial Aneurysms: A Meta-Analysis.

BACKGROUND: Y-stent-assisted coiling for wide-neck intracranial aneurysms required further investigation. PURPOSE: Our aim was to analyze outcomes after Y-stent placement in wide-neck aneurysms. DATA SOURCES: We performed a systematic search of 3 data bases for studies published from 2000 to 2018. STUDY SELECTION: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we included studies reporting Y-stent-assisted coiling of wide-neck aneurysms. DATA ANALYSIS: Random-effects meta-analysis was used to pool the following: aneurysm occlusion rate, complications, and factors influencing the studied outcomes. DATA SYNTHESIS: We included 27 studies and 750 aneurysms treated with Y-stent placement. The immediate complete/near-complete occlusion rate was 82.2% (352/468; 95% CI, 71.4%-93%; I2 = 92%), whereas the long-term complete/near-complete occlusion rate was 95.4% (564/598; 95% CI, 93.7%-97%; I2 = 0%) (mean radiologic follow-up of 14 months). The aneurysm recanalization rate was 3% (20/496; 95% CI, 1.5%-4.5%; I2 = 0%), and half of the recanalized aneurysms required retreatment. The treatment-related complication rate was 8.9% (63/614; 95% CI, 5.8%-12.1%; I2 = 44%). Morbidity and mortality after treatment were 2.4% (18/540; 95% CI, 1.2%-3.7%; I2 = 0%) and 1.1% (5/668; 95% CI, 0.3%-1.9%; I2 = 0%), respectively. Crossing Y-stent placement was associated with a slightly lower complication rate compared with the kissing configuration (56/572 = 8.4%; 95% CI, 5%-11%; I2 = 46% versus 4/30 = 12.7%; 95% CI, 3%-24%; I2 = 0%). Occlusion rates were quite comparable among Enterprise, Neuroform, and LVIS stents, whereas the Enterprise stent was associated with lower rates of complications (8/89 = 6.5%; 95% CI, 1.6%-11%; I2 = 0%) compared with the others (20/131 = 14%; 95% CI, 5%-26%; I2 = 69% and 9/64 = 11%; 95% CI, 3%-20%; I2 = 18%). LIMITATIONS: This was a small, retrospective series. CONCLUSIONS: Y-stent-assisted coiling yields high rates of long-term angiographic occlusion, with a relatively low rate of treatment-related complications. Y-stent placement with a crossing configuration appears to be associated with better outcomes. Although Y-configuration can be obtained using many types of stents with comparable occlusion rates, the Enterprise stent is associated with lower complication rates.

Risk of Branch Occlusion and Ischemic Complications with the Pipeline Embolization Device in the Treatment of Posterior Circulation Aneurysms.

BACKGROUND AND PURPOSE: Flow diversion with the Pipeline Embolization Device is increasingly used for endovascular treatment of intracranial aneurysms due to high reported obliteration rates and low associated morbidity. While obliteration of covered branches in the anterior circulation is generally asymptomatic, this has not been studied within the posterior circulation. The aim of this study was to evaluate the association between branch coverage and occlusion, as well as associated ischemic events in a cohort of patients with posterior circulation aneurysms treated with the Pipeline Embolization Device. MATERIALS AND METHODS: A retrospective review of prospectively maintained databases at 8 academic institutions from 2009 to 2016 was performed to identify patients with posterior circulation aneurysms treated with the Pipeline Embolization Device. Branch coverage following placement was evaluated, including the posterior inferior cerebellar artery, anterior inferior cerebellar artery, superior cerebellar artery, and posterior cerebral artery. If the Pipeline Embolization Device crossed the ostia of the contralateral vertebral artery, its long-term patency was assessed as well. RESULTS: A cohort of 129 consecutive patients underwent treatment of 131 posterior circulation aneurysms with the Pipeline Embolization Device. Adjunctive coiling was used in 40 (31.0%) procedures. One or more branches were covered in 103 (79.8%) procedures. At a median follow-up of 11 months, 11% were occluded, most frequently the vertebral artery (34.8%). Branch obliteration was most common among asymptomatic aneurysms (P < .001). Ischemic complications occurred in 29 (22.5%) procedures. On multivariable analysis, there was no significant difference in ischemic complications in cases in which a branch was covered (P = .24) or occluded (P = .16). CONCLUSIONS: There was a low occlusion incidence in end arteries following branch coverage at last follow-up. The incidence was higher in the posterior cerebral artery and vertebral artery where collateral supply is high. Branch occlusion was not associated with a significant increase in ischemic complications.

Endovascular treatment of deep hemorrhagic brain arteriovenous malformations with transvenous onyx embolization.

SUMMARY: Brain AVMs are a rare cause of cerebral hemorrhage and SAH, and their treatment is still debated. The aim of this study was to describe a novel endovascular approach with transvenous embolization of deep hemorrhagic brain AVMs. Five patients (3 females, 2 males; mean age, 33.2 years) underwent a transvenous embolization of a deep hemorrhagic brain AVM at our institution between February and April 2012. Clinical and angiographic data at the end of the procedure and after 6 months are reported. All the AVMs were completely obliterated, and no intra- or postprocedural complications occurred. The clinical outcome was unchanged or improved in all patients. Transvenous endovascular treatment may be considered in small, hemorrhagic, and deep AVMs with single deep drainage in those cases in which neurosurgical and radiosurgical treatment might not be indicated.

Effects of hyper-early (<12 hours) endovascular treatment of ruptured intracranial aneurysms on clinical outcome.

Despite the encouraging results obtained with the endovascular treatment of ruptured intracranial aneurysms, few data are available on the effects of the timing of this approach on clinical outcome. The aim of our study was to evaluate the effects of the hyper-early timing of treatment and of pre-treatment and treatment-related variables on the clinical outcome of patients with ruptured intracranial aneurysms. Five hundred and ten patients (167 M, 343 F; mean age 56.45 years) with 557 ruptured intracranial aneurysms were treated at our institution from 2000 to 2011 immediately after their admission. The total population was divided into three groups: patients treated within 12 hours (hyper-early, group A), between 12-48 hours (early, group B) and after 48 hours (delayed, group C). A statistical analysis was carried out for global population and subgroups. Two hundred and thirty-four patients (46%) were included in group A, 172 (34%) in group B and 104 (20%) in group C. Pre-treatment variables (Hunt&Hess, Fisher grades, older age) and procedure-related variable (ischaemic/haemorrhagic complications) showed a significant correlation with worse clinical outcomes. The hyper-early treatment showed no correlation with good clinical outcomes. The incidence of intra-procedural complications was not significantly different between the three groups; 1.2% of pre-treatment rebleedings were observed. The hyper-early endovascular treatment of ruptured intracranial aneurysm does not seem to be statistically correlated with good clinical outcomes although it may reduce the incidence of pre-treatment spontaneous rebleedings without being associated with a higher risk of intra-procedural complications. However, since no significant differences in terms of clinical outcome and pre-treatment rebleeding rate were observed, a hyper-early treatment is not be supported by our data.

Five to ten years follow-up after coiling of 241 patients with acutely ruptured aneurysms. A single centre experience.

Endovascular treatment has assumed a role of first choice in the management of ruptured intracranial aneurysms. We describe the clinical and morphological data after the treatment of 258 ruptured intracranial aneurysms in 241 patients, in order to evaluate the safety and the efficacy of the endovascular treatment. Two hundred and forty-one patients with saccular ruptured aneurysms were treated at our institution between 2000 and 2005. After the endovascular treatment a clinical and angiographic follow-up was conducted. The clinical follow-up was carried out with a medical examination and telephonic interviews and mRS was used for evaluation. Two hundred and forty-nine acutely ruptured aneurysms were successfully treated and immediately after the endovascular procedure 81.9% of the aneurysms resulted completely occluded, 12.1% had a residual neck and 6% revealed a residual sac. The evolution of each grade was evaluated at six months and two years. During the follow-up we observed five early and one late re-bleedings. Twenty-four patients underwent a second procedure. After the discharge and up to ten years 73.1% of patients had a good clinical outcome (mRS0-1), 8.9% died and the remainder showed moderate-severe disability (mRS2-3). The long-term stability of the anatomical result is a critic-al issue of this approach because eventual re-bleedings may occur even after several months or years. A careful clinical and radiological follow-up for up to two years after the embolization may prevent recurrences but may not be sufficient.