Ogilvy, Christopher S.

Abstract Introduction The impact of multiple feeding arteries on clinical outcomes of cerebral arteriovenous malformations (AVMs) is not well understood. This study aims to compare outcomes between AVMs with multiple versus single feeding arteries. Patients and Methods Data from the Multicenter International Study for Treatment of Brain AVMs (MISTA) consortium were analyzed. Propensity score matching (PSM) was used to balance cohorts. Subgroup analysis was conducted for ruptured and unruptured AVMs and different treatment options, and multivariable logistic regression was applied to assess the impact of feeding artery origin. Results Among 953 patients, 661(69.4%) had multiple feeding arteries, and 292 (30.6%) had a single feeding artery. After PSM, which included 422 matched patients (211 in each group), the differences in obliteration rates (68.7% vs 74.8%, OR 0.73, 95% CI: 0.48–1.12, p = 0.16) and symptomatic complications (15.6% vs 11.8%, OR 1.37, 95% CI: 0.78–2.41, p = 0.25) were not significant. Subgroup analysis comparing ruptured and unruptured AVMs and different treatment options showed no significant differences across all subgroups. Multivariable analysis identified PICA feeders as significantly associated with increased odds of all complications (OR 7.33, 95% CI: 2.14–25.1, p = 0.002). Discussion and Conclusion AVMs with a single feeding artery were more likely to present with rupture, but no significant differences in obliteration rates or complications were observed between the groups after PSM. These findings suggest that while the number of feeding arteries may influence the initial presentation, it does not appear to impact overall treatment success or patient prognosis. Further prospective studies are needed to confirm these findings.

Background: Arteriovenous malformations (AVMs) are complex vascular anomalies with a high risk of hemorrhage and neurological deficits, especially when located in eloquent brain regions. The eloquence of an AVM location is a critical factor in the treatment planning, influencing both the risk of complications and long-term functional outcomes. This study aims to compare outcomes between eloquent and non-eloquent AVMs. Methods: This multicenter, retrospective study utilized data from the Multicenter International Study for Treatment of Brain AVMs (MISTA) consortium. Patients with eloquent and non-eloquent AVMs were compared on baseline characteristics, angiographic outcomes, and functional outcomes using the modified Rankin Scale (mRS). Propensity score weighting (IPTW) was applied to adjust for confounding variables. Results: The study included 1013 patients, with 498 (49.2%) AVMs located in eloquent regions and 515 (50.8%) in non-eloquent regions. In unadjusted analysis, eloquent AVMs had lower complete obliteration rates (67.6% vs 79.5%, OR: 0.53, 95% CI: 0.39–0.72, p < 0.001) and higher complication rates (24.5% vs 19.0%, OR: 1.38, 95% CI: 1.02–1.86, p = 0.03) compared to non-eloquent AVMs. After IPTW adjustment, eloquent AVMs continued to show significantly higher odds of overall complications (OR: 1.68, 95% CI: 1.12–2.52, p = 0.01) and symptomatic complications (OR: 1.77, 95% CI: 1.12–2.80, p = 0.01). Secondary analysis within the eloquent group indicated that embolization was linked to an elevated risk of complications. Surgery and radiosurgery showed comparable functional outcomes at last follow-up and complications rates with higher complete obliteration rates in surgery. Conclusion: AVMs in eloquent brain areas present higher risks of complications and lower obliteration rates, emphasizing the need for cautious, individualized treatment planning. Within the eloquent group, embolization increased the risk of complications, while surgery and radiosurgery showed comparable functional outcomes at last follow-up and complication rates with higher complete obliteration rates in surgery. These findings highlight the importance of location in AVM management and support further research focusing on comparing treatment strategies for AVMs in eloquent brain areas.

Background Brain arteriovenous malformations (AVMs) are abnormal connections between feeding arteries and draining veins, associated with significant risks of haemorrhage, seizures and other neurological deficits. Preoperative embolization is commonly used as an adjunct to microsurgical resection, with the aim of reducing intraoperative complications and improving outcomes. However, the efficacy and safety of this approach remain controversial. Methods This study is a subanalysis of the Multicenter International Study for Treatment of Brain AVMs consortium. We retrospectively analysed 486 patients with brain AVMs treated with microsurgical resection between January 2010 and December 2023. Patients were divided into two groups: those who underwent microsurgery alone (n=245) and those who received preoperative embolization, followed by microsurgery (n=241). Propensity score matching was employed, resulting in 288 matched patients (144 in each group). The primary outcomes were rates of complete AVM obliteration and functional outcomes (measured by the modified Rankin Scale (mRS)). Secondary outcomes included complication rates, mortality, hospital length of stay and postsurgical rupture. Results After matching, the complete obliteration rate was 97% with no significant difference between the microsurgery-only group and the preoperative embolization group (p=0.12). The proportion of patients with an mRS score of 0–2 at the last follow-up was similar in both groups (83% vs 84%; p=0.67). The median hospital stay was significantly longer for the embolisation group (9 days vs 7 days; p=0.017). Complication rates (24% vs 22%; p=0.57) and mortality rates (4.9% vs 2.1%; p=0.20) were comparable between the two groups. No significant differences were observed in postsurgical rupture, recurrence or retreatment rates. Conclusions In this large multicentre study, preoperative embolization did not significantly improve AVM obliteration rates, functional outcomes or reduce complications compared with microsurgery alone.

Background The contact aspiration (CA) technique is often used to perform endovascular thrombectomy (EVT) for acute ischemic stroke (AIS); however, rescue strategies are necessary if CA fails to achieve recanalization. This study investigates the outcomes of incorporating stent retriever (SR) thrombectomy in the rescue strategy following failed CA. Methods EVT patients with failed CA attempts were identified from a large multicenter registry and stratified by rescue technique: CA alone or incorporating SR in the rescue strategy. Outcomes included successful recanalization, 90-day functional outcomes (defined by the modified Rankin Scale (mRS) score), symptomatic intracranial hemorrhage (sICH), and 90-day mortality. Results Among 1885 patients with failed CA attempts, conversion to SR was associated with higher recanalization rates (85.2% vs 80.6%; p=0.03), higher rates of second-pass recanalization (31.2% vs 23.4%; p<0.001), and better 90-day outcomes (mRS 0–2: 35.2% vs 29.9%; p=0.04) when compared with repeated CA attempts. Trevo SRs showed higher odds of successful recanalization (adjusted odds ratio (aOR)=1.9; p=0.02), second-pass recanalization (aOR=1.7; p=0.01), and reduced odds of sICH (aOR=0.3; p=0.02). EmboTrap SRs were associated with higher odds of 90-day mortality (aOR=2.6; p=0.004) and sICH (aOR=2.9; p=0.04) and lower odds of recanalization (aOR=0.5; p=0.03). Conclusions Incorporating SR in the rescue strategy after a failed CA improves recanalization rates and functional outcomes. Trevo SRs demonstrated superior efficacy and safety when incorporated into the rescue strategy.

OBJECTIVE While the relationship between smoking and subarachnoid hemorrhage is well established, data regarding the probability of detecting unruptured intracranial aneurysms (UIAs) in smokers remain sparse. The aim of this systematic review and meta-analysis is to provide a comprehensive understanding of the relationship between smoking and the likelihood of identifying UIAs in healthy asymptomatic patients who underwent brain imaging for indications unrelated to UIAs. METHODS A systematic review was conducted following the PRISMA guidelines. The PubMed and Scopus databases were searched for studies published before March 2024 that reported on the presence of UIAs in healthy asymptomatic patients who had undergone brain imaging for indications unrelated to UIAs. Three independent reviewers assessed the eligibility of all retrieved studies. Risk of bias for the included observational studies was assessed using the methodological index for non-randomized studies. Data on UIA prevalence, smoking status, and patient and aneurysm characteristics were extracted. The association between smoking and the presence of UIA was studied. A prevalence proportional meta-analysis was conducted across the included studies. A meta-analysis was performed with a random-effects model by using summary statistics from the included studies. RESULTS Six studies involving 47,788 patients who had undergone brain imaging were identified for quantitative analysis. The pooled UIA prevalence in the sample was 3.07% (95% CI 2.27%–4.16%). Patients who smoked had higher rates of aneurysm detection than the patients who did not smoke (pooled prevalence of 2.96%, 95% CI 2.68%–3.27% vs 2.23%, 95% CI 2.08%–2.39%). Although the relation between the two was not statistically significant (p = 0.06), smoking was associated with higher odds for UIA detection, yielding an OR of 1.34 (95% CI 1.07–1.67) with an I 2 value of 53%. CONCLUSIONS This study suggests a potentially higher risk of UIAs in patients who smoked than in those who never smoked. However, the results of this meta-analysis revealed that smoking was not statistically associated with higher UIA detection. This result could be explained by the limited number of studies published on this topic. If these findings reach statistical significance in future larger studies, it could justify revising guidelines to include cigarette smokers in intracranial aneurysm screening.

OBJECTIVE Endovascular intracranial aneurysm (IA) management has significantly evolved over the last 2 decades. Despite these advancements, the aneurysm recanalization rate after coil embolization remains a concern. Statins have been found to affect vascular repair and remodeling; therefore, the authors hypothesized that patients receiving statin therapy at the time of coil embolization would have lower aneurysm recurrence and retreatment rates compared with patients not receiving statin therapy. METHODS A post hoc analysis was conducted of the primary data from patients enrolled in the Hydrogel Endovascular Aneurysm Treatment Trial focusing on the impact of statin use on the recurrence rates of 3- to 14-mm IAs after endovascular coiling. The primary outcome measured included aneurysm recurrence over 18–24 months using the Raymond-Roy Occlusion Classification. Secondary outcomes included major and minor recurrence rates and retreatment rates. Propensity score matching based on patient and aneurysm characteristics was performed to mitigate selection bias. RESULTS A total of 577 patients with data on statin use were eligible for this analysis. Of these, 178 (30.8%) patients were using statins and 399 (69.2%) were not. After propensity score matching, 156 (39.2%) patients were included in the statin group and 242 (60.8%) in the nonstatin group. The recurrence rate was 3.8% (6/156) in the statin group and 10.7% (26/242) in the nonstatin group (p = 0.013). In a subgroup analysis, statin use significantly reduced recurrence in patients with unruptured aneurysms (1.6% vs 9.7%, p = 0.005), but not in those with ruptured aneurysms (12.5% vs 13.6%, p = 0.876). CONCLUSIONS Statin use was associated with a reduced rate of aneurysm recurrence in patients who underwent endovascular coiling for IAs with a decreased rate of retreatment during the follow-up period. Statins are a relatively low-risk treatment and may be an effective therapy to reduce recanalization of IAs, although further prospective studies are warranted to validate these findings.

Background Arteriovenous malformations (AVMs) are uncommon cerebral lesions that can cause significant neurological complications. Surgical resection is the gold standard for treatment, but endovascular embolization and stereotactic radiosurgery (SRS) are viable alternatives. Objective To compare the outcomes of endovascular embolization versus SRS in the treatment of AVMs with Spetzler-Martin grades I–III. Methods This study combined retrospective data from 10 academic institutions in North America and Europe. Patients aged 1 to 90 years who underwent endovascular embolization or SRS for AVMs with Spetzler-Martin grades I–III between January 2010 and December 2023 were included. Results The study included 244 patients, including 84 who had endovascular embolization and 160 who had SRS. Before propensity score matching (PSM), complete obliteration at the last follow-up was achieved in 74.5% of the SRS group compared with 57.8% of the embolization group (OR=0.47; 95% CI 0.26 to 0.48; P=0.01). After propensity score matching, SRS still achieved significantly higher occlusion rates at last follow-up (78.9% vs 55.3%; OR=0.32; 95% CI 0.12 to 0.90; P=0.03). Hemorrhagic complications were higher in the embolization group than in the SRS group, although this difference did not reach statistical significance after PSM (13.2% vs 2.6%; OR=5.6; 95% CI 0.62 to 50.47; P=0.12). Similarly, re-treatment rate was higher in the embolization group (10.5% vs 5.3%; OR=2.11; 95% CI 0.36 to 12.31; P=0.40) compared with the SRS group. Conclusion Our findings indicate that SRS has a significantly higher obliteration rate at last follow-up compared with endovascular embolization. Also, SRS has a higher tendency for fewer hemorrhagic complications and lower re-treatment rate. Further prospective studies are needed.

OBJECTIVE The placement of flow-diverting devices has become a common method of treating unruptured intracranial aneurysms of the internal carotid artery. The progressive improvement of aneurysm occlusion after treatment—with low complication and rupture rates—has led to a dilemma regarding the management of aneurysms in which occlusion has not occurred within 6–24 months. The authors aimed to identify clinical consensus regarding management of intracranial aneurysms displaying persistent filling 6–24 months after flow diversion and to ascertain questions that may drive future investigation. METHODS An international panel of 67 experts was invited to participate in a multistep Delphi consensus process on the treatment of intracranial aneurysms after failed flow diversion. RESULTS Of the 67 experts invited, 23 (34%) participated. Qualitative analysis of an initial survey with open-ended questions resulted in 51 statements regarding management of aneurysms showing persistent filling after flow diversion. The statements were grouped into 8 categories, and in the second round, respondents rated the degree of their agreement with each statement on a 5-point Likert scale. Flow diverters with surface modifiers did not influence administration of dual-antiplatelet therapy according to 83%. Consensus was also reached regarding the definition of treatment failure at specific time points, including at 6 months if there is aneurysm growth or persistent rapid flow through the entirety of the aneurysm (96%), at 12 months if there is aneurysm growth or symptom onset (78%), and at 24 months if there is persistent filling regardless of size and filling characteristics (74%). Although experts agreed that the degree of intimal hyperplasia or in-device stenosis could not be ascertained by noninvasive imaging alone (83%), only 65% chose digital subtraction angiography as the preferred modality. At 6 and 12 months, retreatment is preferred if there is persistent filling with aneurysm growth (96%, 96%), device malposition (48%, 87%), or a history of subarachnoid hemorrhage (65%, 70%), respectively, and at 24 months if there is persistent filling without reduction in aneurysm size (74%). Experts favored treatment with an additional flow diverter (87%) over aneurysm clipping, applying the same principles for follow-up (83%) and treatment failure (91%) as for the first flow diverter. CONCLUSIONS The authors present the consensus practices of experts in the management of intracranial aneurysms without occlusion 6–24 months after treatment with a flow-diverting device.

Background: We present five patients with remodeling of the adult circle of Willis in response to flow diverter stents (FDSs) at the anterior communicating artery (AComA) and the posterior communicating artery (PComA). The observed changes provide a paradigm of how flow change can institute anatomic changes in the adult circle of Willis vasculature. Case Description: In the first two cases, after placement of the FDS covering the AComA, there was an increase in size and flow of the contralateral A1-anterior cerebral artery which had previously been hypoplastic. In one of the cases, this led to the filling of the aneurysm and required placement of coils within the lesion which was curative. In case three, the FDS effect led to asymptomatic occlusion of the PComA and associated aneurysm without change of the ipsilateral P1-segement of posterior-cerebral-artery (P1-PCA) caliber. In the fourth case, the FDS covering an aneurysm with a fetal PCA arising from its neck resulted in significant reduction of the aneurysm size, persistent flow and caliber of the fetal PCA, and the hypoplastic ipsilateral P1-PCA. Finally, in the fifth case, after FDS occlusion of the PComA and aneurysm there was increasement in diameter of the ipsilateral P1-PCA that was previously hypoplastic. Conclusion: The use of FDS can affect vessels covered by the device and other arteries of the circle of Willis adjacent to the FDS. The phenomena illustrated in the hypoplastic branches appear to be a compensatory response to the hemodynamic changes induced by the divertor and to the altered flow in the circle of Willis.

OBJECTIVE Indication for surgery in brainstem cavernous malformations (BSCMs) is based on many case series, few comparative studies, and no randomized controlled trials. The objective of this study was to seek consensus about surgical management aspects of BSCM. METHODS A total of 29 experts were invited to participate in a multistep Delphi consensus process on the surgical treatment of BSCM. RESULTS Twenty-two (76%) of 29 experts participated in the consensus. Qualitative analysis (content analysis) of an initial open-ended question survey resulted in 99 statements regarding surgical treatment of BSCM. By using a multistep survey with 100% participation in each round, consensus was reached on 52 (53%) of 99 statements. These were grouped into 4 categories: 1) definitions and reporting standards (7/14, 50%); 2) general and patient-related aspects (11/16, 69%); 3) anatomical-, timing of surgery–, and BSCM-related aspects (22/37, 59%); and 4) clinical situation–based decision-making (12/32, 38%). Among other things, a consensus was reached for surgical timing, handling of associated developmental venous anomalies, handling of postoperative BSCM remnants, assessment of specific anatomical BSCM localizations, and treatment decisions in typical clinical BSCM scenarios. CONCLUSIONS A summary of typical clinical scenarios and a catalog of various BSCM- and patient-related aspects that influence the surgical treatment decision have been defined, rated, and interpreted.