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Background Whereas mechanical thrombectomy (MT) has become standard-of-care treatment for patients with salvageable brain tissue after acute stroke caused by large-vessel occlusions, the results of MT in patients with medium-vessel occlusions (MEVOs), particularly in the posterior cerebral artery (PCA), are not well known. Methods Using data from the international Stroke Thrombectomy and Aneurysm Registry (STAR), we assessed presenting characteristics and clinical outcomes for patients who underwent MT for primary occlusions in the P2 PCA segment. As a subanalysis, we compared the PCA MeVO outcomes with STAR's anterior circulation MeVO outcomes, namely middle cerebral artery (MCA) M2 and M3 segments. Results Of the 9812 patients in STAR, 43 underwent MT for isolated PCA MeVOs. The patients’ median age was 69 years (interquartile range 61–79), and 48.8% were female. The median NIH Stroke Scale score was 9 (range 6–17). After recanalization, 67.4% of patients achieved successful recanalization (modified treatment in cerebral infarction score [mTICI] ≥ 2b), with a first-pass success rate of 44.2%, and 39.6% achieved a modified Rankin score of 0–2 at 90 days. Nine patients (20.9%) had died by the 90-day follow-up. In comparison with M2 and M3 MeVOs, there were no differences in presenting characteristics among the three groups. Patients with PCA MeVOs were less likely to undergo intra-arterial thrombolysis (4.7% PCA vs. 10.1% M2 vs. 16.2% M3, p = 0.046) or to achieve successful recanalization (mTICI ≥ 2b, 67.4%, 86.7%, 82.3%, respectively, p < 0.001); however, there were no differences in the rates of successful first-pass recanalization (44.2%, 49.8%, 52.3%, respectively, p = 0.65). Conclusions We describe the STAR experience performing MT in patients with PCA MeVOs. Our analysis supports that successful first-pass recanalization can be achieved in PCA MEVOs at a rate similar to that in MCA MeVOs, although further study and possible innovation may be necessary to improve successful PCA MeVO recanalization rates.

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.

Introduction Dural arteriovenous fistulas (dAVFs) have been associated with rapidly progressive dementia in relatively young patients. However, the specific angioarchitecture and characteristics of these dAVFs remain to be fully described. To better understand the specific characteristics of dAVFs associated with cognitive impairment (dAVF‐CI), we utilized the CONDOR multicenter database, which provides a large cohort of dAVF available. By analyzing data from patients with dAVFs‐ CI, we aimed to identify the key features distinguishing these cases and elaborate on the pathophysiology of dAVF‐CI. Methods CONDOR is an international multicenter database comprising 1077 (dAVFs) from 14 international centers. We conducted a retrospective analysis of the CONDOR database, focusing on patients diagnosed with dAVFs‐CI. Propensity score matching analysis was performed to compare Borden type II and type III dAVFs with and without cognitive impairment as control groups. Only dAVFs with cortical venous drainage were included as this aggressive subtype can present with non‐hemorrhagic neurologic deficits. Additionally, logistic regression was then employed to identify significant characteristics associated with dAVF‐CI. Results A total of 60 patients with dAVF‐CI and 60 control dAVFs were included in the analysis. The patients with dAVF‐CI had a mean age of 58 ± 18 years. It was found that all cases of dAVF‐CI exhibited venous hypertension. Additionally, there was a significant association between sinus stenosis and dAVF‐CI (OR: 2.85, 95% CI: 1.16‐7.55, p = 0.027). Moreover, dAVF‐CI cases were characterized by the presence of multiple arteriovenous shunts, with more arterial feeders (OR 1.56, 95% CI 1.22‐2.05, p <0.001) and draining veins (OR 2.05, 95% CI 1.05‐4.46, p = 0.004) compared to the control dAVFs. Venous ectasia was also found to be associated with dAVF‐CI (OR 2.38, 95% CI 1.13‐5.11, p= 0.024). Finally, some patients in which successful dAVF closure was achieved had symptom resolution during follow‐up (OR 2.86, 95% CI 0.85‐9.56, p = 0.09). Conclusion dAVFs‐CI tend to occur in relatively young patients and are characterized by the presence of venous hypertension. The development of sinus stenosis and venous ectasia further hinders proper drainage, contributing to the persistence of venous hypertension. Venous hypertension may impair critical structures such as the thalamus or the cortex leading to rapid cognitive impairment. Successful treatment of dAVFs‐CI can potentially reverse symptoms. Nonetheless, some dAVF‐CI may have persistent symptoms due to chronic hypertension and infarction.

OBJECTIVE Borden-Shucart type I dural arteriovenous fistulas (dAVFs) lack cortical venous drainage and occasionally necessitate intervention depending on patient symptoms. Conversion is the rare transformation of a low-grade dAVF to a higher grade. Factors associated with increased risk of dAVF conversion to a higher grade are poorly understood. The authors hypothesized that partial treatment of type I dAVFs is an independent risk factor for conversion. METHODS The multicenter Consortium for Dural Arteriovenous Fistula Outcomes Research database was used to perform a retrospective analysis of all patients with type I dAVFs. RESULTS Three hundred fifty-eight (33.2%) of 1077 patients had type I dAVFs. Of those 358 patients, 206 received endovascular treatment and 131 were not treated. Two (2.2%) of 91 patients receiving partial endovascular treatment for a low-grade dAVF experienced conversion to a higher grade, 2 (1.5%) of 131 who were not treated experienced conversion, and none (0%) of 115 patients who received complete endovascular treatment experienced dAVF conversion. The majority of converted dAVFs localized to the transverse-sigmoid sinus and all received embolization as part of their treatment. CONCLUSIONS Partial treatment of type I dAVFs does not appear to be significantly associated with conversion to a higher grade.

Background and importance Neurointervention is a very competitive specialty in the United States due to the limited number of training spots and the larger pool of applicants. The training standards are continuously updated to ensure solid training experiences. Factors affecting candidate(s) selection have not been fully established yet. Our study aims to investigate the factors influencing the selection process. Methods A 52-question survey was distributed to 93 program directors (PDs). The survey consisted of six categories: (a) Program characteristics, (b) Candidate demographics, (c) Educational credentials, (d) Personal traits, (e) Research and extracurricular activities, and (f) Overall final set of characteristics. The response rate was 59.1%. As per the programs’ characteristics, neurosurgery was the most involved specialty in running the training programs (69%). Regarding demographics, the need for visa sponsorship held the greatest prominence with a mean score of 5.9 [standard deviation (SD) 2.9]. For the educational credentials, being a graduate from a neurosurgical residency and the institution where the candidate's residency training is/was scored the highest [5.4 (SD = 2.9), 5.4 (SD = 2.5), respectively]. Regarding the personal traits, assessment by faculty members achieved the highest score [8.9 (SD = 1)]. In terms of research/extracurricular activities, fluency in English had the highest score [7.2 (SD = 1.9)] followed by peer-reviewed/PubMed-indexed publications [6.4 (SD = 2.2)]. Conclusion Our survey investigated the factors influencing the final decision when choosing the future neurointerventional trainee, including demographic, educational, research, and extracurricular activities, which might serve as valuable guidance for both applicants and programs to refine the selection process.

Background: Anecdotal cases of rapidly progressing dementia in patients with dural arteriovenous fistulas (dAVFs) and cortical venous drainage have been reported in small series. However, a comprehensive description of the angiographic features of this dAVFs is lacking. We conducted an analysis of the largest cohort of dAVFs presenting with cognitive impairment (dAVFs-CI), aiming to provide a better characterization of this subset of dAVFs. Methods: The CONDOR Consortium, a multicenter repository comprising 1077 dAVFs, served as the study population. Among the dAVFs, patients with dAVFs-CI were analyzed. A propensity scores matching analysis was conducted to compare dAVFs-CI with Borden type II and type III dAVFs without cognitive impairment (controls). Logistic regression was employed to identify angiographic characteristics specific to dAVFs-CI. Post-treatment outcomes were analyzed. Results: A total of 60 patients with dAVFs-CI and 60 control dAVFs were included. Outflow obstruction leading to venous hypertension was observed in all dAVFs-CI. Sinus stenosis was significantly associated with dAVFs-CI (OR 2.85, 95% CI: 1.16-7.55, p = 0.027). dAVFs-CI were more likely to have a higher number of arterial feeders (OR 1.56, 95% CI 1.22-2.05, p < 0.001) and draining veins (OR 2.05, 95% CI 1.05-4.46, p = 0.004). Venous ectasia increased the risk of dAVFs-CI (OR 2.38, 95% CI 1.13-5.11, p = 0.024). A trend toward achieving asymptomatic status at follow-up was observed in patients with successful closure of dAVFs (OR 2.86, 95% CI 0.85-9.56, p = 0.09). Discussion: Venous hypertension is a key angiographic feature dAVFs-CI. dAVFs-CI exhibit a complex angioarchitecture characterized by an increased number of arteriovenous connections and stenosed sinuses. The presence of venous ectasia further exacerbates the impaired drainage and contributes to the development of dAVFs-CI. Notably, closure of the dAVF has the potential to reverse symptoms in certain cases (Figure).

BACKGROUND AND OBJECTIVES: Anecdotal cases of rapidly progressing dementia in patients with dural arteriovenous fistulas (dAVFs) have been reported in small series. However, large series have not characterized these dAVFs. We conducted an analysis of the largest cohort of dAVFs presenting with cognitive impairment (dAVFs-CI), aiming to provide a detailed characterization of this subset of dAVFs. METHODS: Patients with dAVFs-CI were analyzed from the CONDOR Consortium, a multicenter repository comprising 1077 dAVFs. A propensity score matching analysis was conducted to compare dAVFs-CI with Borden type II and type III dAVFs without cognitive impairment (controls). Logistic regression was used to identify angiographic characteristics specific to dAVFs-CI. Furthermore, post-treatment outcomes were analyzed. RESULTS: A total of 60 patients with dAVFs-CI and 60 control dAVFs were included. Outflow obstruction leading to venous hypertension was observed in all dAVFs-CI. Sinus stenosis was significantly associated with dAVFs-CI (OR 2.85, 95% CI: 1.16-7.55, P = .027). dAVFs-CI were more likely to have a higher number of arterial feeders (OR 1.56, 95% CI 1.22-2.05, P < .001) and draining veins (OR 2.05, 95% CI 1.05-4.46, P = .004). Venous ectasia increased the risk of dAVFs-CI (OR 2.38, 95% CI 1.13-5.11, P = .024). A trend toward achieving asymptomatic status at follow-up was observed in patients with successful closure of dAVFs (OR 2.86, 95% CI 0.85-9.56, P = .09) CONCLUSION: Venous hypertension is a key angiographic feature of dAVFs-CI. Moreover, these fistulas present at a mean age of 58 years-old, and exhibit a complex angioarchitecture characterized by an increased number of arteriovenous connections and stenosed sinuses. The presence of venous ectasia further exacerbates the impaired drainage and contributes to the development of dAVFs-CI. Notably, in certain cases, closure of the dAVF has the potential to reverse symptoms.

Background: Despite the well-established potent benefit of mechanical thrombectomy (MT) for large vessel occlusion (LVO) stroke, access to MT has not been studied globally. We conducted a worldwide survey of countries on 6 continents to define MT access (MTA), the disparities in MTA, and its determinants on a global scale. Methods: Our survey was conducted in 75 countries through the Mission Thrombectomy 2020+ global network between November 22, 2020, and February 28, 2021. The primary end points were the current annual MTA, MT operator availability, and MT center availability. MTA was defined as the estimated proportion of patients with LVO receiving MT in a given region annually. The availability metrics were defined as ([current MT operators×50/current annual number of estimated thrombectomy-eligible LVOs]×100 = MT operator availability) and ([current MT centers×150/current annual number of estimated thrombectomy-eligible LVOs]×100= MT center availability). The metrics used optimal MT volume per operator as 50 and an optimal MT volume per center as 150. Multivariable-adjusted generalized linear models were used to evaluate factors associated with MTA. Results: We received 887 responses from 67 countries. The median global MTA was 2.79% (interquartile range, 0.70–11.74). MTA was <1.0% for 18 (27%) countries and 0 for 7 (10%) countries. There was a 460-fold disparity between the highest and lowest nonzero MTA regions and low-income countries had 88% lower MTA compared with high-income countries. The global MT operator availability was 16.5% of optimal and the MT center availability was 20.8% of optimal. On multivariable regression, country income level (low or lower–middle versus high: odds ratio, 0.08 [95% CI, 0.04–0.12]), MT operator availability (odds ratio, 3.35 [95% CI, 2.07–5.42]), MT center availability (odds ratio, 2.86 [95% CI, 1.84–4.48]), and presence of prehospital acute stroke bypass protocol (odds ratio, 4.00 [95% CI, 1.70–9.42]) were significantly associated with increased odds of MTA. Conclusions: Access to MT on a global level is extremely low, with enormous disparities between countries by income level. The significant determinants of MT access are the country’s per capita gross national income, prehospital LVO triage policy, and MT operator and center availability.