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Background: There is yet no randomized controlled evidence that mechanical thrombectomy (MT) is superior to best medical treatment in patients with large vessel occlusion but minor stroke symptoms (National Institutes of Health Stroke Scale (NIHSS) <6). Prior studies of patients with admission NIHSS scores ≥ 6 observed unfavorable functional outcomes despite successful recanalization, commonly termed as futile recanalization (FR), in up to 50% of cases. Aim: The aim of this study is to determine the prevalence of FR in patients with minor stroke and identify associated patient-specific risk factors. Methods: Our multicenter cohort study screened all patients prospectively enrolled in the German Stroke Registry Endovascular Treatment from 2015 to 2021 (n = 13,082). Included were patients who underwent MT for anterior circulation vessel occlusion with a baseline NIHSS score of <6 and successful recanalization (modified Thrombolysis in Cerebral Infarction (mTICI) scores of 2b–3). FR was defined by modified Rankin Scale (mRS) scores of 2–6 at 90 days. Multivariable logistic regression analysis was conducted to explore factors associated with FR. Results: A total of 674 patients met the inclusion criteria. FR occurred in 268 (40%) patients. Multivariable logistic regression analysis indicates that higher age (adjusted odds ratio (aOR) = 1.04 (95% confidence interval (CI) = 1.02–1.06)), pre-stroke mRS 1 (aOR = 2.70 (95% CI = 1.51–4.84)), transfer from admission hospital to comprehensive stroke center (aOR = 1.67 (95% CI = 1.08–2.56)), longer time from symptom onset/last seen well to admission (aOR = 1.02 (95% CI = 1.00–1.04)), MT under general anesthesia (aOR = 1.78 (95% CI = 1.13–2.82)), higher NIHSS after 24 h (aOR = 1.09 (95% CI = 1.05–1.14)), and symptomatic intracranial hemorrhage (aOR = 16.88 (95% CI = 2.03–140.14)) increased the odds of FR. There was no significant difference in primary outcome between achieving mTICI score of 2b or 3. Conclusions: Unfavorable functional outcomes despite successful vessel recanalization were frequent in acute ischemic stroke patients with low NIHSS scores on admission. We provide patient-specific risk factors that indicate an increased risk of FR and should be considered when treating patients with minor stroke. Data accessibility statement: The data that support the findings of our study are available on reasonable request after approval of the German Stroke Registry (GSR) steering committee. [ABSTRACT FROM AUTHOR]

Background Landmark thrombectomy trials have provided evidence that selected patients with large ischemic stroke benefit from successful endovascular therapy, commonly defined as incomplete (modified Thrombolysis In Cerebral Infarction (mTICI) 2b) or complete reperfusion (mTICI 3). We aimed to investigate whether mTICI 3 improves functional outcomes compared with mTICI 2b in large ischemic strokes. Methods This retrospective multicenter cohort study was conducted to compare mTICI 2b versus mTICI 3 in large ischemic strokes in the anterior circulation. Patients enrolled in the German Stroke Registry between 2015-2021 were analyzed. Large ischemic stroke was defined as an Alberta Stroke Program Early CT Score (ASPECTS) of 3-5. Patients were matched by final mTICI grade using propensity score matching. Primary outcome was the 90-day modified Rankin Scale (mRS) score. Results After matching, 226 patients were included. Baseline and imaging characteristics were balanced between mTICI 2b and mTICI 3 patients. There was no shift on the mRS favoring mTICI 3 compared with mTICI 2b in large ischemic strokes (adjusted common odds ratio (acOR) 1.12, 95% confidence interval (95% CI) 0.64 to 1.94, P=0.70). The rate of symptomatic intracranial hemorrhage was higher in mTICI 2b than in mTICI 3 patients (12.6% vs 4.5%, P=0.03). Mortality at 90 days did not differ between mTICI 3 and mTICI 2b (33.6% vs 37.2%; adjusted OR 0.69, 95% CI 0.33 to 1.45, P=0.33). Conclusions In endovascular therapy for large ischemic strokes, mTICI 3 was not associated with better 90-day functional outcomes compared with mTICI 2b. This study suggests that mTICI 2b might be warranted as the final angiographic result, questioning the benefit/risk ratio of additional maneuvers to seek for mTICI 3 in large ischemic strokes. [ABSTRACT FROM AUTHOR]

Background Robust venous outflow (VO) profiles, measured by degree of venous opacification on pre-thrombectomy CT angiography (CTA) studies, are strongly correlated with favorable outcomes in patients with large vessel occlusion acute ischemic stroke treated by thrombectomy. However, VO measurements are laborious and require neuroimaging expertise. Objective To develop a semi-automated method to measure VO using CTA and CT perfusion imaging studies. Methods We developed a graphical interface using The Visualization Toolkit, allowing for voxel selection at the confluence and bilateral internal cerebral veins on CTA along with arterial input functions (AlFs) from both internal carotid arteries. We extracted concentration-time curves from the CT perfusion study at the corresponding locations associated with AIF and venous output function (VOF). Outcome analyses were primarily conducted by the Mann-Whitney U and Jonckheere-Terpstra tests. Results Segmentation at the pre-selected AIF and VOF locations was performed on a sample of 97 patients. 65 patients had favorable VO (VO+) and 32 patients had unfavorable VO (VO-). VO+ patients were found to have a significantly shorter VOF time to peak (8.26; 95% CI 7.07 to 10.34) than VO- patients (9.44; 95% CI 8.61 to 10.91), P=0.007. No significant difference was found in VOF curve width and the difference in time between AIF and VOF peaks. Conclusions Time to peak of VOF at the confluence of sinuses was significantly associated with manually scored venous outflow. Further studies should aim to understand better the association between arterial inflow and venous outflow, and capture quantitative metrics of venous outflow at other locations. [ABSTRACT FROM AUTHOR]

Purpose: The Alberta Stroke Program Early CT Score (ASPECTS) is regularly used to guide patient selection for mechanical thrombectomy (MT). Similarly, penumbral imaging based on computed tomography perfusion (CTP) may serve as neuroimaging tool to guide treatment. Yet, patients with a large ischemic core on CTP may show only minor ischemic changes resulting in a high ASPECTS. Aim: We hypothesized twofold: (1) the treatment effect of vessel recanalization in patients with core volume > 50 mL but ASPECTS ⩾ 6 is not different compared to high ASPECTS patients with core volume < 50 mL, and (2) recanalization is associated with core overestimation. Methods: We conducted an observational study analyzing ischemic stroke patients consecutively treated with MT after triage by multimodal CT. Functional endpoint was the rate of functional independence at Day 90 defined as modified Rankin Scale (mRS) 0–2. Imaging endpoint was core overestimation, which was considered when CTP-derived core was larger than the final infarct volume assessed on follow-up imaging. Recanalization was evaluated with the extended Thrombolysis in Cerebral Infarction (eTICI) scale. Multivariable logistic regression analysis and propensity score matching (PSM) were used to assess the association of recanalization (eTICI ⩾ 2b) with functional outcome and core overestimation. Results: Of 630 patients with ASPECTS ⩾ 6, 91 patients (14.4%) had a large ischemic core. Following 1:1 PSM, the treatment effect of recanalization was not different in patients with large core and ASPECTS ⩾ 6 (+ 25.8%, 95% CI: 16.3–35.4, p < 0.001) compared to patients with ASPECTS ⩾ 6 and core volume < 50 mL (+ 14.9%, 95% CI: 5.7–24.1, p = 0.002). Recanalization (aOR: 3.46, 95% CI: 1.85–6.47, p < 0.001) and higher core volume (aOR: 1.03, 95% CI: 1.02–1.04, p < 0.001) were significantly associated with core overestimation. Conclusion: In patients with ASPECTS ⩾ 6, core volumes did not significantly modify outcomes following recanalization. Reperfusion and higher core volume were significantly associated with core overestimation which may explain the treatment effect of MT for patients with a large ischemic core but minor ischemic changes on non-enhanced CT. Data access statement: The data analyzed in this study will be available and shared on reasonable request from any qualified researcher for the purpose of replicating the results after clearance by the local ethics committee. [ABSTRACT FROM AUTHOR]

Ischemic lesion net water uptake (NWU) represents a quantitative imaging biomarker for cerebral edema in acute ischemic stroke. Data on NWU for distinct occlusion locations remain scarce, but might help to improve the prognostic value of NWU. In this retrospective multicenter cohort study, we compared NWU between patients with proximal large vessel occlusion (pLVO; ICA or proximal M1) and distal large vessel occlusion (dLVO; distal M1 or M2). NWU was quantified by densitometric measurements of the early ischemic region. Arterial collateral status was assessed using the Maas scale. Regression analysis was used to investigate the relationship between occlusion location, NWU and ischemic lesion growth. A total of 685 patients met inclusion criteria. Early ischemic lesion NWU was higher in patients with pLVO compared with dLVO (7.7% vs 3.9%, P <.001). The relationship between occlusion location and NWU was partially mediated by arterial collateral status. NWU was associated with absolute ischemic lesion growth between admission and follow-up imaging (β estimate, 5.50, 95% CI, 3.81–7.19, P <.001). This study establishes a framework for the relationship between occlusion location, arterial collateral status, early ischemic lesion NWU and ischemic lesion growth. Future prognostic thresholds for NWU might be optimized by adjusting for the occlusion location. [ABSTRACT FROM AUTHOR]

Background Vasospasm and delayed cerebral ischemia (DCI) are the leading causes of morbidity and mortality after intracranial aneurysmal subarachnoid hemorrhage (aSAH). Vasospasm detection, prevention and management, especially endovascular management varies from center to center and lacks standardization. We aimed to evaluate this variability via an international survey of how neurointerventionalists approach vasospasm diagnosis and endovascular management. Methods We designed an anonymous online survey with 100 questions to evaluate practice patterns between December 2021 and September 2022. We contacted endovascular neurosurgeons, neuroradiologists and neurologists via email and via two professional societies -- the Society of NeuroInterventional Surgery (SNIS) and the European Society of Minimally Invasive Neurological Therapy (ESMINT). We recorded the physicians' responses to the survey questions. Results A total of 201 physicians (25% [50/201] USA and 75% non-USA) completed the survey over 10 months, 42% had >7 years of experience, 92% were male, median age was 40 (IQR 35-46). Both high-volume and low- volume centers were represented. Daily transcranial Doppler was the most common screening method (75%) for vasospasm. In cases of symptomatic vasospasm despite optimal medical management, endovascular treatment was directly considered by 58% of physicians. The most common reason to initiate endovascular treatment was clinical deficits associated with proven vasospasm/DCI in 89%. The choice of endovascular treatment and its efficacy was highly variable. Nimodipine was the most common first- line intra-arterial therapy (40%). Mechanical angioplasty was considered the most effective endovascular treatment by 65% of neurointerventionalists. Conclusion Our study highlights the considerable heterogeneity among the neurointerventional community regarding vasospasm diagnosis and endovascular management. Randomized trials and guidelines are needed to improve standard of care, determine optimal management approaches and track outcomes. [ABSTRACT FROM AUTHOR]

Background: There is growing evidence suggesting efficacy of endovascular therapy for M2 occlusions of the middle cerebral artery. More than one recanalization attempt is often required to achieve successful reperfusion in M2 occlusions, associated with general concerns about the safety of multiple maneuvers in these medium vessel occlusions. Aim: The aim of this study was to investigate the association between the number of recanalization attempts and functional outcomes in M2 occlusions in comparison with large vessel occlusions (LVO). Methods: Retrospective multicenter cohort study of patients who underwent endovascular therapy for primary M2 occlusions. Patients were enrolled in the German Stroke Registry at 1 of 25 comprehensive stroke centers between 2015 and 2021. The study cohort was subdivided into patients with unsuccessful reperfusion (mTICI 0–2a) and successful reperfusion (mTICI 2b–3) at first, second, third, fourth, or ⩾fifth recanalization attempt. Primary outcome was 90-day functional independence defined as modified Rankin Scale score of 0–2. Safety outcome was the occurrence of symptomatic intracranial hemorrhage. Internal carotid artery or M1 occlusions were defined as LVO and served as comparison group. Results: A total of 1078 patients with M2 occlusion were included. Successful reperfusion was observed in 87.1% and 90-day functional independence in 51.9%. The rate of functional independence decreased gradually with increasing number of recanalization attempts (p < 0.001). In both M2 occlusions and LVO, successful reperfusion within three attempts was associated with greater odds of functional independence, while success at ⩾fourth attempt was not. Patients with ⩾4 attempts exhibited higher rates of symptomatic intracranial hemorrhage in M2 occlusions (6.5% vs 2.7%, p = 0.02) and LVO (7.2% vs 3.5%, p < 0.001). Conclusion: This study suggests a clinical benefit of successful reperfusion within three recanalization attempts in endovascular therapy for M2 occlusions, which was similar in LVO. Our findings reduce concerns about the risk–benefit ratio of multiple attempts in M2 medium vessel occlusions. Data access statement: The data that support the findings of this study are available on reasonable request after approval of the German Stroke Registry (GSR) steering committee. Clinical Trial Registration Information: ClinicalTrials.gov Identifier: NCT03356392 [ABSTRACT FROM AUTHOR]

Objective: Mechanical thrombectomy (MT) is of benefit to patients with ischemic stroke; however, the effect of recanalization on lesion pathophysiology is not yet well understood. The aim of this study was to quantitatively assess how the effect of vessel recanalization on clinical outcome is mediated by edema reduction versus penumbra salvage. Methods: Consecutive analysis was made of anterior circulation ischemic stroke patients triaged by multimodal computed tomography (CT) undergoing MT. Edema reduction was defined using the difference of quantitative net water uptake (NWU) determined on baseline and follow‐up CT (∆NWU). Penumbra salvage volume (PSV) was defined as the difference between admission penumbra and net infarct growth volumes to follow‐up. Mediation analyses were performed with vessel recanalization as independent variable (modified Thrombolysis in Cerebral Infarction ≥ 2b) and ∆NWU/PSV as mediator variables. Modified Rankin Scale scores at 90 days served as endpoint. Results: Of 422 included patients, 321 (76%) achieved successful recanalization. The median ∆NWU was 6.8% (interquartile range [IQR] = 3.9–10.4), and the median PSV was 66ml (IQR = 8–124). ∆NWU, PSV, and recanalization were significantly associated with functional outcome in logistic regression analysis. ∆NWU and PSV partially mediated the relationship between recanalization and outcome. Sixty‐six percent of the relationship between recanalization and functional outcome could be explained by treatment‐induced edema reduction, whereas 22% was mediated by PSV (p < 0.0001). Interpretation: Compared to penumbra salvage, edema reduction was a stronger mediator of the effect of recanalization on functional outcome. Given the current trials on adjuvant neuroprotectants also targeting ischemic edema formation, combining reperfusion with antiedematous neuroprotectants may have synergistic effects resulting in better outcomes in patients with ischemic stroke. ANN NEUROL 2024;95:137–145 [ABSTRACT FROM AUTHOR]