Background and Purpose— Endovascular treatment for large vessel occlusion in ischemic stroke has proven to be effective in large clinical trials. We aimed to provide real-world estimates of endovascular treatment reperfusion rates and functional outcome on a countrywide scale. Methods— Two thousand seven hundred ninety-four patients with large vessel occlusion were included into an investigator-initiated, industry-independent, prospective registry in 25 sites in Germany between June 2015 and April 2018. The primary outcome was the score on the modified Rankin Scale ranging from zero (no symptoms) to 6 (death) at 3 months. Secondary analyses included the prediction of a good outcome (modified Rankin Scale, 0–2). Dichotomized analyses of predictors were performed using logistic regression adjusted for potential confounders. Results— Median age was 75 years (interquartile range, 64–82); median National Institutes of Health Stroke Scale score was 15 (interquartile range, 10–19). Vessel occlusion was in the anterior circulation in 2265 patients (88%) and in the posterior circulation in 303 patients (12%). Intravenous alteplase before endovascular treatment was given in 1457 patients (56%). Successful reperfusion was achieved in 2143 subjects (83%). At 3 months, 854 patients (37%) showed a good outcome; mortality was 29%. There was no difference between anterior and posterior circulation occlusions ( P =0.27). Significant predictors for a good outcome were younger age (odds ratio [OR], 1.06; 95% CI, 1.05–1.07), no interhospital transfer (OR, 1.39; 95% CI, 1.03–1.88), lower stroke severity (OR, 1.10; 95% CI, 1.08–1.13), smaller infarct size (OR, 1.26; 95% CI, 1.15–1.39), alteplase use (OR, 1.49; 95% CI, 1.08–2.06), and reperfusion success (OR, 1.69; 95% CI, 1.45–1.96). Conclusions— High rates of favorable outcome can be achieved on a countrywide scale by endovascular treatment. Mortality appears to be greater in the daily routine than otherwise reported by authors of large randomized trials. There were no outcome differences between the anterior and posterior circulation. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT03356392.

Background and Purpose- Early selection of patients with acute middle cerebral artery infarction at risk for malignant edema is critical to initiate timely decompressive surgery. Net water uptake (NWU) per brain volume is a quantitative imaging biomarker of space-occupying ischemic edema which can be measured in computed tomography. We hypothesize that NWU in early infarct lesions can predict development of malignant edema. The aim was to compare NWU in acute brain infarct against other common predictors of malignant edema. Methods- After consecutive screening of single-center registry data, 153 patients with acute proximal middle cerebral artery occlusion fulfilled the inclusion criteria. A total of 29 (18.2%) patients developed malignant edema defined as end point in follow-up imaging leading to decompressive surgery and death as a direct implication of mass effect. Early infarct lesion volume and NWU were quantified in multimodal admission computed tomography; time from symptom onset to admission imaging was recorded. Results- Mean time from onset to admission imaging was equivalent between patients with and without malignant infarcts (mean±SD: 3.3±1.4 hours and 3.3±1.7 hours, respectively). Edematous tissue expansion by NWU within infarct lesions occurred across all patients in this cohort (NWU: 9.1%±6.8%; median, 7.9%; interquartile range, 8.8%; range, 0.1%-35.6%); 7.0% (±5.2) in nonmalignant and 18.0% (±5.7) in malignant infarcts. Based on univariate receiver operating characteristic curve analysis, NWU >12.7% or an edema rate >3.7% NWU/h identified malignant infarcts with high discriminative power (area under curve, 0.93±0.02). In multivariate binary logistic regression, the probability of malignant infarct was significantly associated with early infarct volume and NWU. Conclusions- Computed tomography-based quantitative NWU in early infarct lesions is an important surrogate marker for developing malignant edema. Besides volume of early infarct, the measurements of lesion water uptake may further support identifying patients at risk for malignant infarction.

Volume of water uptake in infarct lesions can be calculated quantitatively by relative CT density measurements. Voxel-wise imaging of water uptake depicts lesion pathophysiology and could serve as a quantitative imaging biomarker of acute infarct lesions.

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Background and Purpose: Patients with acute ischemic stroke due to large vessel occlusion and favorable tissue-level collaterals (TLCs) likely have robust cortical venous outflow (VO). We hypothesized that favorable VO predicts robust TLC and good clinical outcomes. Methods: Multicenter retrospective cohort study of consecutive acute ischemic stroke due to large vessel occlusion patients who underwent thrombectomy triage. Included patients had interpretable prethrombectomy computed tomography, computed tomography angiography, and cerebral perfusion imaging. TLCs were measured on cerebral perfusion studies using the hypoperfusion intensity ratio (volume ratio of brain tissue with [Tmax >10 s/Tmax >6 s]). VO was determined by opacification of the vein of Labbé, sphenoparietal sinus, and superficial middle cerebral vein on computed tomography angiography as 0, not visible; 1, moderate opacification; and 2, full. Clinical and demographic data were determined from the electronic medical record. Using multivariable regression analyses, we determined the association between VO and (1) favorable TLC status (defined as hypoperfusion intensity ratio ≤0.4) and (2) good functional outcome (modified Rankin Scale score, 0–2). Results: Six hundred forty-nine patients met inclusion criteria. Patients with favorable VO were younger (median age, 72 [interquartile range (IQR), 62–80] versus 77 [IQR, 66–84] years), had a lower baseline National Institutes of Health Stroke Scale (median, 12 [IQR, 7–17] versus 19 [IQR, 13–20]), and had a higher Alberta Stroke Program Early Computed Tomography Score (median, 9 [IQR, 7–10] versus 7 [IQR, 6–9]). Favorable VO strongly predicted favorable TLC (odds ratio, 4.5 [95% CI, 3.1–6.5]; P <0.001) in an adjusted regression analysis. Favorable VO also predicted good clinical outcome (odds ratio, 10 [95% CI, 6.2–16.0]; P <0.001), while controlling for favorable TLC, age, glucose, baseline National Institutes of Health Stroke Scale, and good vessel reperfusion status. Conclusions: In this selective retrospective cohort study of acute ischemic stroke due to large vessel occlusion patients undergoing thrombectomy triage, favorable VO profiles correlated with favorable TLC and were associated with good functional outcomes after treatment. Future prospective studies should independently validate our findings.

Benefit of endovascular recanalization beyond established treatment time windows likely exists in select stroke patients. However, there is currently no imaging model that predicts infarction adjusting for elapsed time between the pathologic snapshot of admission imaging until endovascular recanalization. We trained and cross validated a multivariate generalized linear model (GLM) that uses computer tomography perfusion and clinical data to quantify patient-specific dynamic change of tissue infarction depending on degree and time of recanalization. Multicenter data of 161 patients with proximal anterior circulation occlusion undergoing endovascular therapy were included. Multivariate voxelwise infarct probability was calculated within the GLM. The effect of increasing time to treatment and degree of recanalization on voxelwise infarction was calculated in each patient. Tissue benefit of successful relative to unsuccessful recanalization was shown up to 15 hours after onset in individual patients and decreased nonlinearly with time. On average, the relative reduction of infarct volume at the treatment interval of 5 hours was 53% and this salvage effect decreased by 5% units per hour to o 5% after 10 additional hours to treatment. Treatment time-adjusted multivariate prediction of infarction by perfusion and clinical status may identify patients who benefit from extended time to recanalization therapy.

Studies evaluating the effect of reperfusion on ischemic edema in acute stroke described conflicting results. Net water uptake (NWU) per brain volume is a new quantitative imaging biomarker of space-occupying ischemic edema, which can be measured in computed tomography (CT). We sought to investigate the effects of vessel recanalization on the formation of ischemic brain edema using quantitative NWU. In this multicenter observational study, acute ischemic stroke patients with a large vessel occlusion (LVO) in the anterior circulation were consecutively screened. Patients with vessel recanalization (thrombolysis in cerebral infarction (TICI) 2 b or 3) versus persistent vessel occlusion (no thrombectomy, TICI 0-1) were compared. Lesion-NWU was quantified in multimodal admission CT and follow-up CT (FCT), and ΔNWU was calculated as difference. Of 194 included patients, 150 had successful endovascular recanalization and 44 persistent LVO. In FCT after treatment, the mean (standard deviation) ΔNWU was 15.8% (5.7) in patients with persistent LVO and 9.8% (5.8) with vessel recanalization ( p < 0.001). In multivariate regression analysis, vessel recanalization was independently associated with a lowered ΔNWU by 6.3% compared to LVO (95% confidence interval: 3.7–9.0, p < 0.001). Successful vessel recanalization was associated with a significantly reduced formation of ischemic brain edema. Quantitative NWU may be used to compare the treatment effects in acute stroke.

Background and Purpose— In acute ischemic stroke, mechanical thrombectomy allows flow restoration in the majority of cases. In case of an unsuccessful retrieval, little is known about how many retrieval attempts should be performed before stopping the procedure. This study assessed the recanalization rate and clinical outcome per retrieval maneuver. Methods— In this analysis, 330 patients with acute large vessel occlusion treated exclusively with stentrieval devices were included. Successful recanalization was defined as Thrombolysis in Cerebral Infarction 2b-3, a good clinical outcome was defined as modified Rankin Scale at 90 days of ≤2. Results— The median number of retrieval attempts was 1 (interquartile range, 1–2, maximum 8). Recanalization rates per retrieval attempt were highest for the first retrieval (46.8%) and lowest for the fifth retrieval (22.7%). After 3 retrieval attempts, 67.9% of patients were successfully recanalized. Patients with 1 to 3 retrieval attempts had higher rates of good clinical outcome (28.9% versus 7.4%; P =0.018). The number of passes was an independent negative predictor of good clinical outcome (adjusted odds ratio, 0.65; 95% CI, 0.435–0.970; P =0.035). Conclusions— Two-thirds of occlusions were successfully recanalized with up to 3 retrieval attempts. Further attempts had good recanalization rates, but the rate of favorable clinical outcome did not improve.