Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations.

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

Assessment of Thrombectomy versus Combined Thrombolysis and Thrombectomy in Patients with Acute Ischemic Stroke and Medium Vessel Occlusion.

Background The combination of intravenous thrombolysis (IVT) with mechanical thrombectomy (MT) may have clinical benefits for patients with medium vessel occlusion. Purpose To examine whether MT combined with IVT is associated with different outcomes than MT alone in patients with acute ischemic stroke (AIS) and medium vessel occlusion. Materials and Methods This retrospective study included consecutive adult patients with AIS and medium vessel occlusion treated with MT or MT with IVT at 37 academic centers in North America, Asia, and Europe. Data were collected from September 2017 to July 2021. Propensity score matching was performed to reduce confounding. Univariable and multivariable logistic regression analyses were performed to test the association between the addition of IVT treatment and different functional and safety outcomes. Results After propensity score matching, 670 patients (median age, 75 years [IQR, 64-82 years]; 356 female) were included in the analysis; 335 underwent MT alone and 335 underwent MT with IVT. Median onset to puncture (350 vs 210 minutes, P < .001) and onset to recanalization (397 vs 273 minutes, P < .001) times were higher in the MT group than the MT with IVT group, respectively. In the univariable regression analysis, the addition of IVT was associated with higher odds of a modified Rankin Scale (mRS) score 0-2 (odds ratio [OR], 1.44; 95% CI: 1.06, 1.96; P = .019); however, this association was not observed in the multivariable analysis (OR, 1.37; 95% CI: 0.99, 1.89; P = .054). In the multivariable analysis, the addition of IVT also showed no evidence of an association with the odds of first-pass effect (OR, 1.27; 95% CI: 0.9, 1.79; P = .17), Thrombolysis in Cerebral Infarction grades 2b-3 (OR, 1.64; 95% CI: 0.99, 2.73; P = .055), mRS scores 0-1 (OR, 1.27; 95% CI: 0.91, 1.76; P = .16), mortality (OR, 0.78; 95% CI: 0.49, 1.24; P = .29), or intracranial hemorrhage (OR, 1.25; 95% CI: 0.88, 1.76; P = .21). Conclusion Adjunctive IVT may not provide benefit to MT in patients with AIS caused by distal and medium vessel occlusion. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Wojak in this issue.

Use of the pRESET LITE thrombectomy device in combined approach for medium vessel occlusions: A multicenter evaluation.

PURPOSE: Our purpose was to assess the efficacy and safety of the pRESET LITE stent retriever (Phenox, Bochum, Germany), designed for medium vessel occlusion (MeVO) in acute ischemic stroke (AIS) patients with a primary MeVO. METHODS: We performed a retrospective analysis of the MAD MT Consortium, an integration of prospectively maintained databases at 37 academic institutions in Europe, North America, and Asia, of AIS patients who underwent mechanical thrombectomy with the pRESET LITE stent retriever for a primary MeVO. We subcategorized occlusions into proximal MeVOs (segments A1, M2, and P1) vs. distal MeVOs/DMVO (segments A2, M3-M4, and P2). We reviewed patient and procedural characteristics, as well as angiographic and clinical outcomes. RESULTS: Between September 2016 and December 2021, 227 patients were included (50% female, median age 78 [65-84] years), of whom 161 (71%) suffered proximal MeVO and 66 (29%) distal MeVO. Using a combined approach in 96% of cases, successful reperfusion of the target vessel (mTICI 2b/2c/3) was attained in 85% of proximal MeVO and 97% of DMVO, with a median of 2 passes (IQR: 1-3) overall. Periprocedural complications rate was 7%. Control CT at day 1 post-MT revealed a hemorrhagic transformation in 63 (39%) patients with proximal MeVO and 24 (36%) patients with DMVO, with ECASS-PH type hemorrhagic transformations occurring in 3 (1%) patients. After 3 months, 58% of all MeVO and 63% of DMVO patients demonstrated a favorable outcome (mRS 0-2). CONCLUSION: Mechanical thrombectomy using the pRESET LITE in a combined approach with an aspiration catheter appears effective for primary medium vessel occlusions across several centers and physicians.

Assessment of Aptamer-Targeted Contrast Agents for Monitoring of Blood Clots in Computed Tomography and Fluoroscopy Imaging.

Objective: Random formation of thrombi is classified as a pathological process that may result in partial or complete obstruction of blood flow and limited perfusion. Further complications include pulmonary embolism, thrombosis-induced myocardial infraction, ischemic stroke, and others. Location and full delineation of the blood clot are considered to be two clinically relevant aspects that could streamline proper diagnosis and treatment follow-up. In this work, we prepared two types of X-ray attenuating contrast formulations, using fibrinogen aptamer as the clot-seeking moiety. Methods: Two novel aptamer-targeted formulations were designed. Iodine-modified bases were directly incorporated into a fibrinogen aptamer (iodo-FA). Isothermal titration calorimetry was used to confirm that these modifications did not negatively impact target binding. Iodo-FA was tested for its ability to produce concentration-dependent contrast enhancement in a phantom CT. It was subsequently tested in vitro with clotted human and swine blood. This allowed for translation into ex vivo testing, using fluoroscopy. FA was also used to functionalize gold nanoparticles (FA-AuNPs), and contrast capabilities were confirmed. This formulation was tested in vitro using clotted human blood in a CT scan. Results: Unmodified FA and iodo-FA demonstrated a nearly identical affinity toward fibrin, confirming that base modifications did not impact target binding. Iodo-FA and FA-AuNPs both demonstrated excellent concentration-dependent contrast enhancement capabilities (40.5 HU mM-1 and 563.6 HU µM-1, respectively), which were superior to the clinically available agent, iopamidol. In vitro CT testing revealed that iodo-FA is able to penetrate into the blood clots, producing contrast enhancement throughout, while FA-AuNPs only accumulated on the surface of the clot. Iodo-FA was thereby translated to ex vivo testing, confirming target-binding associated accumulation of the contrast material at the location of the clot within the dilation of the external carotid artery. This resulted in a 34% enhancement of the clot. Conclusions: Both iodo-FA and FA-AuNPs were confirmed to be effective contrast formulations in CT. Targeting of fibrin, a major structural constituent of thrombi, with these novel contrast agents would allow for higher contrast enhancement and better clot delineation in CT and fluoroscopy.

SCENT Trial.

Background and Purpose- To evaluate the safety and effectiveness of the Surpass Flow Diverter (Surpass; Stryker Neurovascular, Fremont, CA) in the treatment of large or giant wide-neck intracranial aneurysms at one year, we hypothesize that treatment with Surpass meets or improves on historical safety and efficacy end points. Methods- SCENT trial (Surpass Intracranial Aneurysm Embolization System Pivotal Trial to Treat Large or Giant Wide Neck Aneurysms) is a multicenter, prospective, single-arm, nonrandomized, interventional trial of the Surpass Flow Diverter for uncoilable or previously treated but failed aneurysms of the intracranial internal carotid artery extending from the petrous segment to the carotid terminus at its bifurcation into anterior and middle cerebral arteries. For enrollment in SCENT, target aneurysms had to be wide-neck (≥4 mm) and large or giant size (≥10 mm). Study results are compared with performance goals derived from a thorough review of the medical literature. The primary effectiveness end point included 3 components: complete aneurysm occlusion, absence of significant parent artery stenosis (≥50%), and no retreatment at 12 months. The primary safety end point was major ipsilateral stroke (increase in National Institutes of Health Stroke Scale score of ≥4) or neurological death within 12 months. Results- At 26 medical centers, 180 patients with 180 target aneurysms were enrolled in the modified intention-to-treat cohort. Per angiographic core lab assessment, there were 15 (8.3%) fusiform, 164 (91.1%) saccular aneurysms, and 1 (0.6%) blister aneurysm. Mean aneurysm size was 12.0 mm. Thirteen (7.4%) aneurysms were giant (≥25 mm). Fifty-eight (32.2%) aneurysms were located in the supraclinoid and distal (including posterior communicating artery) segments of the internal carotid artery. Mean procedure duration was 53.6 minutes. The device was successfully implanted in 97.8% of patients with a mean of 1.1 devices per patient. SCENT met both primary safety and effectiveness end points: 12-month primary effectiveness rate was 62.8% [(113/180); 95% CI, 55.3-69.9] and 12-month major ipsilateral stroke or neurological death rate was 8.3% [(15/180); 95% CI, 4.7-13.4]. Conclusions- Surpass provides safe and effective flow diversion of large or giant, wide-neck, intracranial internal carotid artery aneurysms. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT01716117.

Middle meningeal artery embolization as standalone treatment versus combined with surgical evacuation for chronic subdural hematomas: systematic review and meta-analysis.

OBJECTIVE: Middle meningeal artery embolization (MMAE) is a novel treatment for chronic subdural hematomas (cSDHs) with high variability of use across practitioners and institutions. This study sought to investigate whether standalone MMAE may be an effective alternative to combined MMAE and surgery for select patients with cSDH. METHODS: The authors searched the Medline and Embase databases for studies reporting outcomes specific to standalone MMAE and combined MMAE and surgery. The Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool was used to assess risk of bias in each included study. Patient characteristics were compared between cohorts, and rates of surgical recurrence of standalone MMAE and combined MMAE and surgery were pooled using random-effects models. RESULTS: Four hundred two unique patients (156 with standalone MMAE and 246 with combined MMAE and surgery) were identified across 8 studies. Overall, the subdural thickness for the standalone MMAE group was modestly but statistically significantly smaller (16.8 vs 18.8 mm, estimated p value 0.002), and the mean follow-up time was significantly longer for the standalone MMAE group (5.4 vs 2.3 months, estimated p value < 0.001); there were no significant differences between age, sex, and anticoagulant use. The surgical recurrence rates were not significantly different between the two groups (estimated p value 0.63). Using random-effects models, the surgical recurrence rates were estimated at 6.8% (95% CI 3.5%-11.2%) and 4.6% (95% CI 2.3%-7.7%) for standalone MMAE and combined MMAE and surgery, respectively. CONCLUSIONS: Standalone MMAE for cSDH may yield a low rate of surgical recurrence, which may be comparable to that of combined MMAE and surgery. However, studies in this systematic review and meta-analysis were primarily single-arm studies prone to treatment bias. Future studies are needed to further investigate whether standalone MMAE may be an effective alternative to combined MMAE and surgical treatment for cSDH in select patients.

MEK signaling represents a viable therapeutic vulnerability of KRAS-driven somatic brain arteriovenous malformations.

Brain arteriovenous malformations (bAVMs) are direct connections between arteries and veins that remodel into a complex nidus susceptible to rupture and hemorrhage. Most sporadic bAVMs feature somatic activating mutations within KRAS, and endothelial-specific expression of the constitutively active variant KRASG12D models sporadic bAVM in mice. By leveraging 3D-based micro-CT imaging, we demonstrate that KRASG12D-driven bAVMs arise in stereotypical anatomical locations within the murine brain, which coincide with high endogenous Kras expression. We extend these analyses to show that a distinct variant, KRASG12C, also generates bAVMs in predictable locations. Analysis of 15,000 human patients revealed that, similar to murine models, bAVMs preferentially occur in distinct regions of the adult brain. Furthermore, bAVM location correlates with hemorrhagic frequency. Quantification of 3D imaging revealed that G12D and G12C alter vessel density, tortuosity, and diameter within the mouse brain. Notably, aged G12D mice feature increased lethality, as well as impaired cognition and motor function. Critically, we show that pharmacological blockade of the downstream kinase, MEK, after lesion formation ameliorates KRASG12D-driven changes in the murine cerebrovasculature and may also impede bAVM progression in human pediatric patients. Collectively, these data show that distinct KRAS variants drive bAVMs in similar patterns and suggest MEK inhibition represents a non-surgical alternative therapy for sporadic bAVM.

Impact of duration of dual anti-platelet therapy on risk of complications after stent-assisted coiling of unruptured aneurysms.

BACKGROUND: The optimal duration for dual antiplatelet therapy (DAPT) after stent-assisted coiling (SAC) of intracranial aneurysms is unclear. Longer-term therapy may reduce thrombotic complications but increase the risk of bleeding complications. METHODS: A retrospective review of prospectively maintained data at 12 institutions was conducted on patients with unruptured intracranial aneurysms who underwent SAC between January 1, 2016 and December 31, 2020, and were followed ≥6 months postprocedure. The type and duration of DAPT, stent(s) used, outcome, length of follow-up, complication rates, and incidence of significant in-stent stenosis (ISS) were collected. RESULTS: Of 556 patients reviewed, 450 met all inclusion criteria. Nine patients treated with DAPT <29 days after SAC and 11 treated for 43-89 days were excluded from the final analysis as none completed their prescribed duration of treatment. Eighty patients received short-term DAPT. There were no significant differences in the rate of thrombotic complications during predefined periods of risk in the short, medium, or long-term treatment groups (1/80, 1.3%; 2/188, 1.1%; and 0/162, 0%, respectively). Similarly, no differences were found in the rate of hemorrhagic complications during period of risk in any group (0/80, 0%; 3/188, 1.6%; and 1/162, 0.6%, respectively). Longer duration DAPT did not reduce ISS risk in any group. CONCLUSIONS: Continuing DAPT >42 days after SAC did not reduce the risk of thrombotic complications or in-stent stenosis, although the risk of additional hemorrhagic complications remained low. It may be reasonable to discontinue DAPT after 42 days following non-flow diverting SAC of unruptured intracranial aneurysms.

The natural history of aneurysms incompletely occluded by placement of a flow diverter: a multiinstitutional study.

OBJECTIVE: Treatment of intracranial aneurysms by flow diversion is safe and effective and is increasingly popular. However, the correct treatment paradigm for aneurysms incompletely treated by initial placement of a flow diverter has not been established, nor have the subsequent natural history and occlusion rates of such aneurysms. The authors sought to outline the natural history of such aneurysms, which to date have been considered partially treated. METHODS: The authors retrospectively reviewed consecutive cases from 6 high-volume neurointerventional services, including all cases in which the first follow-up imaging after placement of a flow diverter showed incomplete occlusion of the aneurysm, and for which subsequent clinical and/or radiological follow-up was available. All included patients were treated with the Pipeline Flex embolization device or the Pipeline Flex embolization device with Shield Technology. Subsequent radiographic and clinical outcome data were collected and analyzed using the Kaplan-Meier survival function. RESULTS: A total of 263 patients with persistently patent aneurysms on first follow-up imaging after flow diversion were identified. Of these, 204 had clinical follow-up and 152 had additional imaging follow-up. Of this final cohort, 148 aneurysms were unruptured, and 4 were ruptured. The average aneurysm size by maximum dimension was 10.8 mm. The average recorded follow-up was 27.8 months in the cohort, with some patients followed for as long as 9 years from treatment. Over the course of 403 person-years of follow-up, no delayed aneurysm ruptures were recorded. Both with and without retreatment, aneurysms showed a trend toward progressive occlusion over time. Complications related to device placement were low. CONCLUSIONS: Aneurysms that have been incompletely treated by flow diversion have a benign natural history with progression toward occlusion over time, with or without retreatment.

First pass effect as an independent predictor of functional outcomes in medium vessel occlusions: An analysis of an international multicenter study.

INTRODUCTION: First pass effect (FPE), achievement of complete recanalization (mTICI 2c/3) with a single pass, is a significant predictor of favorable outcomes for endovascular treatment (EVT) in large vessel occlusion stroke (LVO). However, data concerning the impact on functional outcomes and predictors of FPE in medium vessel occlusions (MeVO) are scarce. PATIENTS AND METHODS: We conducted an international retrospective study on MeVO cases. Multivariable logistic modeling was used to establish independent predictors of FPE. Clinical and safety outcomes were compared between the two study groups (FPE vs non-FPE) using logistic regression models. Good outcome was defined as modified Rankin Scale 0-2 at 3 months. RESULTS: Eight hundred thirty-six patients with a final mTICI ⩾ 2b were included in this analysis. FPE was observed in 302 patients (36.1%). In multivariable analysis, hypertension (aOR 1.55, 95% CI 1.10-2.20) and lower baseline NIHSS score (aOR 0.95, 95% CI 0.93-0.97) were independently associated with an FPE. Good outcomes were more common in the FPE versus non-FPE group (72.8% vs 52.8%), and FPE was independently associated with favorable outcome (aOR 2.20, 95% CI 1.59-3.05). 90-day mortality and intracranial hemorrhage (ICH) were significantly lower in the FPE group, 0.43 (95% CI, 0.25-0.72) and 0.55 (95% CI, 0.39-0.77), respectively. CONCLUSION: Over 2/3 of patients with MeVOs and FPE in our cohort had a favorable outcome at 90 days. FPE is independently associated with favorable outcomes, it may reduce the risk of any intracranial hemorrhage, and 3-month mortality.

Incidence and clinical outcomes of perforations during mechanical thrombectomy for medium vessel occlusion in acute ischemic stroke: A retrospective, multicenter, and multinational study.

BACKGROUND: Mechanical thrombectomy (MT) has revolutionized the treatment of acute ischemic stroke (AIS) due to large vessel occlusion (LVO), but its efficacy and safety in medium vessel occlusion (MeVO) remain less explored. This multicenter, retrospective study aims to investigate the incidence and clinical outcomes of vessel perforations (confirmed by extravasation during an angiographic series) during MT for AIS caused by MeVO. METHODS: Data were collected from 37 academic centers across North America, Asia, and Europe between September 2017 and July 2021. A total of 1373 AIS patients with MeVO underwent MT. Baseline characteristics, procedural details, and clinical outcomes were analyzed. RESULTS: The incidence of vessel perforation was 4.8% (66/1373). Notably, our analysis indicates variations in perforation rates across different arterial segments: 8.9% in M3 segments, 4.3% in M2 segments, and 8.3% in A2 segments (p = 0.612). Patients with perforation had significantly worse outcomes, with lower rates of favorable angiographic outcomes (TICI 2c-3: 23% vs 58.9%, p < 0.001; TICI 2b-3: 56.5% vs 88.3%, p < 0.001). Functional outcomes were also worse in the perforation group (mRS 0-1 at 3 months: 22.7% vs 36.6%, p = 0.031; mRS 0-2 at 3 months: 28.8% vs 53.9%, p < 0.001). Mortality was higher in the perforation group (30.3% vs 16.8%, p = 0.008). CONCLUSION: This study reveals that while the occurrence of vessel perforation in MT for AIS due to MeVO is relatively rare, it is associated with poor functional outcomes and higher mortality. The findings highlight the need for increased caution and specialized training in performing MT for MeVO. Further prospective research is required for risk mitigation strategies.

The Influence of Coagulopathy on Radiographic and Clinical Outcomes in Patients Undergoing Middle Meningeal Artery Embolization as Standalone Treatment for Non-acute Subdural Hematomas.

Middle meningeal artery embolization (MMAE) is emerging as a safe and effective standalone intervention for non-acute subdural hematomas (NASHs); however, the risk of hematoma recurrence after MMAE in coagulopathic patients is unclear. To characterize the impact of coagulopathy on treatment outcomes, we analyzed a multi-institutional database of patients who underwent standalone MMAE as treatment for NASH. We classified 537 patients who underwent MMAE as a standalone intervention between 2019 and 2023 by coagulopathy status. Coagulopathy was defined as use of anticoagulation/antiplatelet agents or pre-operative thrombocytopenia (platelets <100,000/µL). Demographics, pre-procedural characteristics, in-hospital course, and patient outcomes were collected. Thrombocytopenia, aspirin use, antiplatelet agent use, and anticoagulant use were assessed using univariate and multivariate analyses to identify any characteristics associated with the need for rescue surgical intervention, mortality, adverse events, and modified Rankin Scale score at 90-day follow-up. Propensity score-matched cohorts by coagulopathy status with matching covariates adjusting for risk factors implicated in surgical recurrence were evaluated by univariate and multivariate analyses. Minimal differences in pre-operative characteristics between patients with and those without coagulopathy were observed. On unmatched and matched analyses, patients with coagulopathy had higher rates of requiring subsequent surgery than those without (unmatched: 9.9% vs. 4.3%; matched: 12.6% vs. 4.6%; both p < 0.05). On matched multivariable analysis, patients with coagulopathy had an increased odds ratio (OR) of requiring surgical rescue (OR 3.95; 95% confidence interval [CI] 1.68-9.30; p < 0.01). Antiplatelet agent use (ticagrelor, prasugrel, or clopidogrel) was also predictive of surgical rescue (OR 4.38; 95% CI 1.51-12.72; p = 0.01), and patients with thrombocytopenia had significantly increased odds of in-hospital mortality (OR 5.16; 95% CI 2.38-11.20; p < 0.01). There were no differences in follow-up radiographic and other clinical outcomes in patients with and those without coagulopathy. Patients with coagulopathy undergoing standalone MMAE for treatment of NASH may have greater risk of requiring surgical rescue (particularly in patients using antiplatelet agents), and in-hospital mortality (in thrombocytopenic patients).

Multicenter evaluation of mechanical thrombectomy for distal medium vessel occlusions with National Institute of Health Stroke Scale Scores ≥ 6 and ≤ 6.

BACKGROUND: While mechanical thrombectomy is considered standard of care for large vessel occlusions, scientific evidence to support treatment for distal and medium vessel occlusions remains scarce. PURPOSE: To evaluate feasibility, safety, and outcomes in patients with low National Institute of Health Stroke Scale scores undergoing mechanical thrombectomy for treatment of distal medium vessel occlusions. MATERIALS AND METHODS: Retrospective data review and analysis of prospectively maintained databases at 41 academic centers in North America, Asia, and Europe between January 2017 and January 2022. Characteristics and outcomes were compared between groups with low stroke scale score (≤ 6) versus and higher stroke scale scores (> 6). Propensity score matching using the optimal pair matching method and 1:1 ratio was performed. RESULTS: Data were collected on a total of 1068 patients. After propensity score matching, there were a total of 676 patients included in the final analysis, with 338 patients in each group. High successful reperfusion rates were seen in both groups, 90.2% in ≤ 6 and 88.7% in the > 6 stroke scale groups. The frequency of excellent and good functional outcome was seen more common in low versus higher stroke scale score patients (64.5% and 81.1% versus 39.3% and 58.6%, respectively). The 90-day mortality rate observed in the ≤ 6 stroke scale group was 5.3% versus 13.3% in the > 6 stroke scale group. CONCLUSION: Mechanical thrombectomy in distal and medium vessel occlusions, specifically in patients with low stroke scale scores is feasible, though it may not necessarily improve outcomes over IVT.

Outcomes with General Anesthesia Compared to Conscious Sedation for Endovascular Treatment of Medium Vessel Occlusions: Results of an International Multicentric Study.

BACKGROUND: Optimal anesthetic strategy for the endovascular treatment of stroke is still under debate. Despite scarce data concerning anesthetic management for medium and distal vessel occlusions (MeVOs) some centers empirically support a general anesthesia (GA) strategy in these patients. METHODS: We conducted an international retrospective study of MeVO cases. A propensity score matching algorithm was used to mitigate potential differences across patients undergoing GA and conscious sedation (CS). Comparisons in clinical and safety outcomes were performed between the two study groups GA and CS. The favourable outcome was defined as a modified Rankin Scale (mRS) 0-2 at 90 days. Safety outcomes were 90-days mortality and symptomatic intracranial hemorrhage (sICH). Predictors of a favourable outcome and sICH were evaluated with backward logistic regression. RESULTS: After propensity score matching 668 patients were included in the CS and 264 patients in the GA group. In the matched cohort, either strategy CS or GA resulted in similar rates of good functional outcomes (50.1% vs. 48.4%), and successful recanalization (89.4% vs. 90.2%). The GA group had higher rates of 90-day mortality (22.6% vs. 16.5%, p < 0.041) and sICH (4.2% vs. 0.9%, p = 0.001) compared to the CS group. Backward logistic regression did not identify GA vs CS as a predictor of good functional outcome (OR for GA vs CS = 0.95 (0.67-1.35)), but GA remained a significant predictor of sICH (OR = 5.32, 95% CI 1.92-14.72). CONCLUSION: Anaesthetic strategy in MeVOs does not influence favorable outcomes or final successful recanalization rates, however, GA may be associated with an increased risk of sICH and mortality.

The Role and Therapeutic Implications of Inflammation in the Pathogenesis of Brain Arteriovenous Malformations.

Brain arteriovenous malformations (bAVMs) are focal vascular lesions composed of abnormal vascular channels without an intervening capillary network. As a result, high-pressure arterial blood shunts directly into the venous outflow system. These high-flow, low-resistance shunts are composed of dilated, tortuous, and fragile vessels, which are prone to rupture. BAVMs are a leading cause of hemorrhagic stroke in children and young adults. Current treatments for bAVMs are limited to surgery, embolization, and radiosurgery, although even these options are not viable for ~20% of AVM patients due to excessive risk. Critically, inflammation has been suggested to contribute to lesion progression. Here we summarize the current literature discussing the role of the immune system in bAVM pathogenesis and lesion progression, as well as the potential for targeting inflammation to prevent bAVM rupture and intracranial hemorrhage. We conclude by proposing that a dysfunctional endothelium, which harbors the somatic mutations that have been shown to give rise to sporadic bAVMs, may drive disease development and progression by altering the immune status of the brain.

Flow Diverter Performance in Aneurysms Arising From the Posterior Communicating Artery: A Systematic Review and Meta-Analysis.

BACKGROUND: Flow diverters (FDs) have demonstrated a safe and effective profile. However, the use of FDs for posterior communicating artery (PComA) aneurysms remains controversial. OBJECTIVE: To evaluate the safety and effectiveness of FDs for PComA aneurysms using a systematic review and meta-analysis of the literature. METHODS: We performed a systematic search from inception until June 2022 for flow diversion in PComA aneurysms. Primary effectiveness was the rate of complete aneurysm occlusion defined by Raymond-Roy class 1. Primary safety outcomes were treatment-related ischemic/hemorrhagic (composite) events causing morbidity and mortality. Secondary safety was PComA patency at follow-up. Random-effects meta-analyses were used to calculate proportions, and statistical heterogeneity was assessed. RESULTS: A total of 13 studies with 397 patients harboring 403 aneurysms were included. Mean age was 48 years, and the mean aneurysm size was 5.3 mm. Most aneurysms were unruptured (65%). Complete occlusion at final follow-up was 73% (CI 66%-79%), and adjunctive coils were used in 10% of aneurysms. Retreatment rate was 2% (CI 0%-9%). The primary safety composite outcome was 4% (CI 3%-7%), and mortality was 1%. PComA patency at final follow-up was 76% (CI 57%-89%). Subgroup analysis, patients with fetal PComAs had a lower complete occlusion rate (42% fetal PComA vs 77%, psubgroupdifference = <.01). CONCLUSION: The performance of FDs in PComA aneurysms is comparable with outcomes found in other subtypes of supraclinoid aneurysms. Effectiveness was acceptable and safety favorable. However, effectiveness was suboptimal in patients with fetal-type PComAs; alternative treatments should be considered in these cases.

Safety and efficacy of the surpass streamline for intracranial aneurysms (SESSIA): A multi-center US experience pooled analysis.

BACKGROUND AND PURPOSE: Flow diversion has established as standard treatment for intracranial aneurysms, the Surpass Streamline is the only FDA-approved braided cobalt/chromium alloy implant with 72-96 wires. We aimed to determine the safety and efficacy of the Surpass in a post-marketing large United States cohort. MATERIALS AND METHODS: This is a retrospective multicenter study of consecutive patients treated with the Surpass for intracranial aneurysms between 2018 and 2021. Baseline demographics, comorbidities, and aneurysm characteristics were collected. Efficacy endpoint included aneurysm occlusion on radiographic follow-up. Safety endpoints were major ipsilateral ischemic stroke or treatment-related death. RESULTS: A total of 277 patients with 314 aneurysms were included. Median age was 60 years, 202 (73%) patients were females. Hypertension was the most common comorbidity in 156 (56%) patients. The most common location of the aneurysms was the anterior circulation in 89% (279/314). Mean aneurysm dome width was 5.77 ± 4.75 mm, neck width was 4.22 ± 3.83 mm, and dome/neck ratio was 1.63 ± 1.26. Small-sized aneurysms were 185 (59%). Single device was used in 94% of the patients, mean number of devices per patient was 1.06. At final follow-up, complete obliteration rate was 81% (194/239). Major stroke and death were encountered in 7 (3%) and 6 (2%) cases, respectively. CONCLUSION: This is the largest cohort study using a 72-96 wire flow diverter. The Surpass Streamline demonstrated a favorable safety and efficacy profile, making it a valuable option for treating not only large but also wide-necked small and medium-sized intracranial aneurysms.

Incidence and outcome of perforations during medium vessel occlusion compared with large vessel occlusion thrombectomy.

BACKGROUND: Vessel perforation during thrombectomy is a severe complication and is hypothesized to be more frequent during medium vessel occlusion (MeVO) thrombectomy. The aim of this study was to compare the incidence and outcome of patients with perforation during MeVO and large vessel occlusion (LVO) thrombectomy and to report on the procedural steps that led to perforation. METHODS: In this multicenter retrospective cohort study, data of consecutive patients with vessel perforation during thrombectomy between January 1, 2015 and September 30, 2022 were collected. The primary outcomes were independent functional outcome (ie, modified Rankin Scale 0-2) and all-cause mortality at 90 days. Binomial test, chi-squared test and t-test for unpaired samples were used for statistical analysis. RESULTS: During 25 769 thrombectomies (5124 MeVO, 20 645 LVO) in 25 stroke centers, perforation occurred in 335 patients (1.3%; mean age 72 years, 62% female). Perforation occurred more often in MeVO thrombectomy (2.4%) than in LVO thrombectomy (1.0%, p<0.001). More MeVO than LVO patients with perforation achieved functional independence at 3 months (25.7% vs 10.9%, p=0.001). All-cause mortality did not differ between groups (overall 51.6%). Navigation beyond the occlusion and retraction of stent retriever/aspiration catheter were the two most common procedural steps that led to perforation. CONCLUSIONS: In our cohort, perforation was approximately twice as frequent in MeVO than in LVO thrombectomy. Efforts to optimize the procedure may focus on navigation beyond the occlusion site and retraction of stent retriever/aspiration catheter. Further research is necessary in order to identify thrombectomy candidates at high risk of intraprocedural perforation and to provide data on the effectiveness of endovascular countermeasures.

Silk Vista Baby for the Treatment of Complex Posterior Inferior Cerebellar Artery Aneurysms.

BACKGROUND: Treatment of small-caliber vessel lesions using flow diverters remains challenging because of vasculature's narrow luminal diameter and tortuosity. This in turn makes navigation and delivery of conventional devices with standard microcatheters more difficult. The Silk Vista Baby (SVB, Balt) flow diversion device was designed for ease of use in vessels with a smaller diameter, distal lesions, and 0.017 ″ microcatheter delivery systems. OBJECTIVE: To report the outcomes of the SVB device on the treatment of posterior inferior cerebellar artery (PICA) aneurysms. METHODS: Databases from different centers were retrospectively reviewed for PICA aneurysms treated with SVB. Demographic information, clinical presentation, radiographic characteristics, procedural complications, and immediate postprocedure outcomes were obtained. RESULTS: Fourteen patients harboring 15 true PICA aneurysms were treated between January 2019 and June 2021. Nine were female (n = 9/14; 64.2%), and the mean age was 51 ± 14.9 years. Most patients had previously ruptured aneurysms, treated by another endovascular technique. Six aneurysms were located distally (n = 6/15; 40%). The mean neck size was 3 mm (SD 1.35, range 2.5-5 mm), whereas the mean PICA diameter was 1.6 mm (SD 0.26, range 1.5-1.7 mm). The mean length of follow-up was 6 months (SD 8.28, range 4.5-16 months). Treatment-related adverse events included 1 case of transient hypoesthesia. Two additional events were reported, but adjudicated as unrelated to the procedure. Complete occlusion, measured as Raymond-Roy class I, was achieved in all cases. CONCLUSION: The SVB device was safely and effectively used in the treatment of PICA aneurysms. The smaller delivery system profile reduces the risk of procedure complications and creates new treatment options for distal lesions.

Predictors and outcomes of first pass efficacy in posterior circulation strokes: Insights from STAR collaboration.

Background: First-pass efficacy (FPE) has been established as an important predictor of favorable functional outcomes after endovascular thrombectomy (ET) in anterior circulation strokes. In this retrospective cohort study, we investigate predictors and clinical outcomes of FPE in posterior circulation strokes (pcAIS). Methods: The Stroke Thrombectomy and Aneurysm Registry database was used to identify pcAIS patients who achieved FPE. Their baseline characteristics and outcomes were compared with the non-FPE group. The primary outcome was a 90-day modified Rankin Scale (mRS) of 0-3. Univariate (UVA) and multivariate (MVA) analyses were done to evaluate predictors of FPE. Safety outcomes included distal emboli, vessel rupture, symptomatic intracranial hemorrhage, and mortality. Results: Of 359 patients, 179 (50%) achieved FPE. Clot burden, occlusion site, and ET technique-related variables were similar between the two groups except for shorter procedure time with FPE. The primary outcome was significantly better with FPE (56.4% vs. 32.8%, p < 0.001). Complications were similar except for a higher rate of distal emboli in non-FPE group (11.1% vs. 3.2%, p = 0.032). Atrial fibrillation (Afib) had increased odds (aOR: 2.06, 95% CI; 1.24, 3.4, p = 0.005) and prior ischemic stroke had decreased odds (aOR: 0.524, 95% CI; 0.28, 0.97, p = 0.04) of FPE. Afib was the only independent predictor of FPE on MVA (1.94, 95% CI; 1.1, 3.43, p = 0.022). Conclusions: Higher rate of FPE in Afib-related pcAIS could possibly be explained by the differences in clot composition and degree of in-situ atherosclerotic disease burden. Future studies are warranted to explore the relationship of clot composition with ET outcomes.