Levitt, Michael R.

OBJECTIVE Cognard type V dural arteriovenous fistulas (dAVFs), defined by spinal perimedullary venous drainage, represent a rare and aggressive neurovascular pathology. Comprehensive multicenter data remain scarce. The authors present the largest multicenter analysis to date, characterizing presentation, radiology, treatment, complications, and functional outcomes of Cognard type V dAVFs. METHODS The authors retrospectively analyzed patients with angiographically confirmed Cognard type V dAVFs from the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR), spanning 16 academic centers. Patient demographics, imaging features, treatment strategies, procedural complications, and modified Rankin Scale (mRS) scores were recorded. RESULTS Among 1077 patients with dAVFs, 37 (3%) had Cognard type V lesions. The mean patient age was 57 years, and 59.5% of patients were male. Most presented with nonhemorrhagic neurological deficits (68%), while 14% had hemorrhage. The most common location was the foramen magnum (32%). Embolization was the primary treatment in 67% of cases, complete obliteration was achieved in 71% of cases. Upfront microsurgery was performed in 22% of patients (obliteration rate 88%), and radiosurgery in 14% (success rate 40%). Salvage treatment further improved obliteration outcomes. Temporary complications occurred in 8% of patients (3/37): 2 with transient neurological deficits postembolization and 1 with transient hydrocephalus after surgery. Permanent complications were observed in 3% (1/37) due to treatment-related hemorrhage. At the last follow-up (mean 2.4 years), 69% (24/35) of patients maintained or improved to an mRS score ≤ 2. No deaths occurred. Functional improvement was seen in 29% (10/35), while mRS decline was in 40% of patients (14/35), all unrelated to the dAVF itself. CONCLUSIONS Cognard type V dAVFs carry a high risk of neurological morbidity. However, favorable functional outcomes are achievable with timely, multimodal intervention. Complication rates remain low, with most being transient. These data support aggressive but tailored management to prevent permanent disability in this high-risk population.

Background Randomized trials have shown equivocal outcomes between a direct aspiration as first-pass technique (ADAPT) and stent retriever (SR) stroke thrombectomy, yet whether specific patient subgroups benefit differentially from one technique over the other remains unknown. Methods In this retrospective multicenter cohort study, patients with large vessel occlusion were included, and those who underwent ADAPT versus SR first-pass thrombectomy (either as standalone or combined with aspiration) were compared. The primary outcome was a composite of first-pass effect (FPE, modified Thrombolysis In Cerebral Infarction (mTICI) 2c or better with one attempt) with no symptomatic intracranial hemorrhage (sICH). A causal forest model was used to estimate the conditional average treatment effect (CATE) for each patient, with larger CATEs indicating that ADAPT is expected to be more advantageous. Patients were stratified by CATEs, and outcomes were compared between treatment groups. Results Among 6700 included patients, ADAPT (n=3695, 55%) was associated with a higher rate of FPE with no sICH (39.9% vs 26.9%; adjusted OR (aOR) 2.07, 95% CI 1.77 to 2.41, P<0.001). The causal forest identified significant treatment effect heterogeneity (interaction P<0.001), where ADAPT was more advantageous in more recent years and among patients with M1 occlusions presenting in earlier time windows. Low-CATE patients showed no statistically significant difference between techniques (aOR 0.91, 95% CI 0.57 to 1.45, P=0.70), while medium- and high-CATE patients demonstrated progressively larger ADAPT advantages (aOR 2.06, 95% CI 1.67 to 2.55, and aOR 2.99, 95% CI 2.24 to 3.98, respectively, both P<0.001). Conclusions ADAPT may be superior to SR for a majority of patients, particularly in recent years, and among patients with M1 occlusions presenting in earlier time windows.

OBJECTIVE Endovascular thrombectomy (EVT) for acute large-vessel occlusion stroke is well established, yet its role in patients presenting with minor stroke symptoms (National Institutes of Health Stroke Scale [NIHSS] score < 6) remains unclear. Prior studies have not accounted for intraprocedural factors that may influence outcomes in this subgroup. METHODS The authors analyzed 5693 patients from the STAR (Stroke and Thrombectomy and Aneurysm Registry), including 398 with low NIHSS scores, to evaluate the association between procedure time (PT) and outcomes. Among patients with low NIHSS scores, propensity score matching was used to compare outcomes between those with PT ≤ 35 versus > 35 minutes, a cutoff defined using receiver operating characteristic curve analysis. The authors performed a meta-analysis of studies reporting best medical management (BMM) outcomes in patients with low NIHSS scores. To compare these with EVT-treated patients, a matched BMM comparator cohort using stratification on pooled baseline characteristics was constructed. Outcomes included 90-day functional independence (modified Rankin Scale [mRS] scores 0–2), intracranial hemorrhage, and mortality. RESULTS PT had a stronger negative effect on outcomes in patients with low NIHSS scores compared with those with high scores, with a steeper decline in functional independence per minute of PT (slope: –0.45% vs –0.21%; p = 0.03 for interaction). Among patients with low scores, PT ≤ 35 minutes was associated with higher 90-day functional independence compared with the propensity score–matching cohort with PT > 35 minutes (82.6% vs 59.0%, p < 0.001). When benchmarked against BMM (75.2% mRS scores 0–2), patients undergoing EVT within 35 minutes had superior outcomes (85.1%, p = 0.047). In contrast, EVT with PT > 35 minutes resulted in worse outcomes than BMM (mRS scores 0–2: 59.8%, p = 0.008). The number needed to treat for PT ≤ 35 minutes was 10, whereas PT > 35 minutes yielded a number needed to harm of 6. CONCLUSIONS PT critically modulates the benefit of EVT in minor stroke. While efficient EVT yields better outcomes than BMM, prolonged procedures are associated with harm. These findings may explain prior inconsistent evidence on EVT in patients with low NIHSS scores and underscore the need to individualize procedural thresholds in this population.

OBJECTIVE The objective was to evaluate the trajectories of hematoma resolution and functional improvement after middle meningeal artery embolization (MMAE) for chronic subdural hematoma (cSDH), model the temporal pattern of cSDH resolution, and identify factors associated with favorable outcomes. METHODS This real-world multicenter retrospective study included cSDH patients treated with MMAE at 24 centers between 2019 and 2024. Hematoma thickness was measured at baseline and at follow-up intervals (1–4 weeks, 1–3 months, 3–6 months, 6–12 months, and > 12 months after embolization). Resolution patterns were modeled using exponential decay functions. Modified Rankin Scale (mRS) scores assessed functional outcomes. Good functional outcome was defined as mRS score ≤ 2. Resolution patterns were modeled using exponential decay functions to estimate time to 50% and 80% reduction. Patients were categorized as complete resolution (≥ 99%) or by quartile of the remaining distribution (substantial [73%–98%], moderate [53%–73%], partial [27%–53%], minimal [< 27%]). The primary outcome was good functional status (mRS score ≤ 2). RESULTS The authors analyzed a total of 1781 patients with 2295 cSDHs who underwent MMAE. The mean ± SD age was 72.8 ± 12.4 years and 68.1% of patients were male. The initial mean hematoma thickness was 15.31 ± 6.53 mm, decreasing to 5.24 ± 5.91 mm at final follow-up (mean reduction 64.3% ± 42.1%). Resolution followed an exponential decay pattern, with an estimated time to 50% reduction of 1.8 months and to 80% reduction of 8.9 months. Complete resolution occurred in 1031 of 2224 patients (46.4%) with complete follow-up. The median (IQR) mRS score improved from 1 (0–3) at baseline to 0 (0–2) at > 12 months. Good functional outcomes were more common in patients with complete versus minimal resolution (68.9% vs 35.0%, p < 0.001). Achieving ≥ 73% resolution within 90 days was associated with better outcomes (good outcome in 76.9% of those with ≥ 73% resolution vs 67.3% in those without, p < 0.001). Neurological deterioration was the strongest predictor of lack of good outcome (23.7% in patients with neurological deterioration vs 82.4% without, p < 0.001). CONCLUSIONS After MMAE for cSDH, reduction in hematoma thickness follows a predictable exponential decay pattern. Greater extent (≥ 80%) and faster timing (within 90 days) of resolution are valuable prognostic indicators. Functional outcomes improve progressively through 6–12 months after the procedure. The relationship between resolution extent and functional outcomes provides quantitative benchmarks for evaluating treatment response.

BACKGROUND: Hemorrhagic risk in dural arteriovenous fistulas (dAVFs) is largely determined by venous anatomy, but the contribution of systemic cardiovascular factors and their medical therapy remains poorly defined. This study examined associations between cardiovascular risk factors and antithrombotic use and hemorrhagic presentation, angiographic obliteration, and early functional outcomes after treatment. METHODS: We analyzed 1350 adults with intracranial dAVFs from the international Consortium for Dural Arteriovenous Fistula Outcomes Research registry, which retrospectively accrued cases across 14 centers in 4 countries between 1990 and 2017. Demographics, cardiovascular comorbidities, antithrombotic use, angioarchitectural features, treatment strategies, and follow-up outcomes were collected from prospectively maintained databases. Primary end points were hemorrhagic presentation, angiographic obliteration, and 90-day functional status after treatment. Univariable and multivariable logistic regressions were performed with model-specific adjustments. RESULTS: Hemorrhage occurred in 375 patients (27.8%) and was most strongly associated with high-grade dAVF classification and male sex; antithrombotic therapy was associated with lower odds of hemorrhagic presentation. Other cardiovascular risk factors showed no independent relationship with bleeding. Angiographic obliteration was achieved in 621 of 845 patients (73.5%). Hemorrhagic onset, high dAVF grade, and surgical treatment were independently associated with angiographic obliteration, whereas smoking and embolization demonstrated only nonsignificant trends after adjustment. At 90 days, 934 patients (88.9%) were functionally independent. Baseline modified Rankin Scale score was the strongest factor associated with 90-day functional outcome, while neither cardiovascular comorbidities nor treatment modality independently influenced functional status. CONCLUSIONS: In this large multicenter dAVF cohort, hemorrhagic presentation was most strongly associated with venous angioarchitecture. Male sex and antithrombotic therapy were also independently associated with hemorrhagic presentation. Angiographic obliteration was common, particularly among surgically treated lesions, and 90-day functional outcome was most strongly associated with baseline functional status.

OBJECTIVE Dural arteriovenous fistulas (dAVFs) are rare cerebrovascular anomalies. Tentorial dAVFs (TDAVFs) have more aggressive features, making them prone to symptomatic presentations and hemorrhage. TDAVFs are heterogenous and require tailored surgical approaches. Presented is a multicenter analysis of TDAVF surgical outcomes. METHODS The Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) consortium compiled data on dAVFs from 16 international centers from 1990 to 2021 retrospectively. Microsurgical treatment success was defined as angiographically confirmed complete obliteration of the fistula or discontinuation of cortical venous drainage (CVD) in high-grade TDAVFs. TDAVF subtypes and tailored surgical approaches were reviewed. RESULTS Of 1360 patients in CONDOR, 161 had TDAVFs and 27% (44/161) of these patients underwent surgical management, with the majority (52% [23/44]) receiving surgery as a salvage treatment following failed embolization. The mean age (SD) of this cohort was 56 (15) years, and 68% (30/44) were male. In total, 91% (40/44) of surgically treated patients presented with aggressive symptoms: 64% (28/44) presented with hemorrhage and 27% (12/44) with nonhemorrhagic neurological deficit (NHND). The median (IQR) duration from symptom onset to diagnosis was 1 (1–4) day. The median time (IQR) between diagnosis and surgery was 15 (3–80) days. Surgical approaches varied across the cohort, with the retrosigmoid being the most common (44% [18/41]), followed by the midline suboccipital (24% [10/41]) and occipital (15% [6/41]) approaches. Perioperative complications occurred in 11% (5/44) of cases, as well as permanent neurological deficits in 2% (1/44). Surgical success was achieved in 90% of patients (38/42). During the mean 3-year follow-up, 2 patients experienced a recurrence of their fistula including representation of CVD (2/38 [5%]) and 1 patient had a new NHND (1/43 [2%]). Shorter symptom duration was significantly associated with success (15.6 vs 181.5 days, p = 0.001). Primary versus salvage microsurgery showed no difference in outcomes. Both patients with recurrent fistula were effectively treated with Gamma Knife radiosurgery. CONCLUSIONS Resection is safe and durable for the treatment of TDAVF not otherwise amenable to embolization. It can achieve a high degree of success with a low rate of perioperative complications and permanent neurological deficits, benefits far exceeding the risks associated with TDAVF natural history or management with less effective modalities.

Abstract Background Recent trials have furthered uncertainty regarding the endovascular benefit for medium vessel occlusions (MeVO). Stent retrievers (SR) were employed in the first attempt in most interventional arm participants. We sought to compare outcomes in acute MCA M2 occlusions between frontline aspiration and SR, and to delineate procedural and anatomical covariates associated with differential treatment effect. Methods Retrospective analysis of a multicenter stroke thrombectomy cohort identified cases of MT for M2 occlusions. Unmatched and propensity score-matched (PSM) cohorts were generated comparing frontline aspiration to standalone and combined SR. The primary outcome was functional independence (mRS 0–2) at 90 days. Recanalization, symptomatic intracranial hemorrhage (sICH), mortality, and the effect of M2 laterality, division occlusion and procedure time were assessed. Results About 1734 patients with M2 occlusions underwent either frontline aspiration (n = 711) or SR/combined (n = 958) thrombectomy between 2013 and 2024. PSM analysis favored aspiration for functional independence (49.9% vs 44.0%, OR 1.27 (1.03–1.57)), complete recanalization (61.2% vs 48.7%, OR 1.66 (1.34–2.05)), complete first pass effect (35.0% vs 27.6%, OR 1.42 (1.13–1.78)), and sICH (3.5% vs 6.2%, OR 0.55 (0.33–0.91)), with no difference in mortality. Frontline aspiration had significantly shorter procedural times (median 28 [IQR 15–49.5] vs 51 [IQR 35–78] minutes; p &lt; 0.001). For every minute increase in procedure time, the probability of functional independence decreased significantly (p &lt; 0.001) less with frontline aspiration (0.35%) compared to SR/combined (1.61%). Conclusion Frontline aspiration for M2 occlusions resulted in better clinical and angiographic outcomes compared to SRs. Future trials for MeVO with a focus on contact aspiration thrombectomy may succeed where recent trials have failed.

Stereotactic radiosurgery was associated with a higher obliteration rate compared with embolization in patients with eloquent brain arteriovenous malformations, whereas there was no evidence of a difference in functional outcomes or complications after adjustment.

Background Endovascular thrombectomy (EVT) has transformed acute ischemic stroke (AIS) care, with onset-to-puncture (OTP) time widely recognized as a critical determinant of outcome. However, emerging evidence suggests that in-hospital procedure time (PT)—from arterial puncture to final recanalization—may have an equally or more significant impact. This study examines the relative contribution of PT versus OTP to functional outcomes in patients with AIS undergoing EVT. Methods A retrospective analysis was conducted of 6644 patients with AIS treated at 44 international stroke centers from the Stroke Thrombectomy and Aneurysm Registry (STAR; 2016–2023). Multivariable regression, time-equivalence analysis, and marginal effects modeling were used to assess associations between PT, OTP, and 90-day modified Rankin Scale (mRS) outcomes. Centers were stratified by procedural efficiency and compared using propensity score matching (PSM). Mediation analysis evaluated whether PT accounted for inter-center differences. Results PT and OTP were independently associated with functional outcomes; however, PT had a significantly stronger effect (adjusted OR for mRS 0–2: PT=0.56 vs OTP=0.96 per hour). Each 5 min increase in PT was equivalent to 78–100 min of additional OTP in outcome impact. Centers with faster average PT had higher rates of functional independence (number needed to treat (NNT)=10), fewer complications, and lower symptomatic intracranial hemorrhage rates. PT significantly mediated the relationship between center tier and outcomes (Sobel’s P<0.001). Conclusion While minimizing OTP remains important, PT exerts a greater influence on outcomes after EVT. Procedural efficiency should be emphasized in stroke systems of care and included in center performance metrics to improve patient outcomes.