Background We determined whether a comprehensive assessment of cerebral collateral blood flow is associated with ischemic lesion edema growth in patients successfully treated by thrombectomy. Methods This was a multicenter retrospective study of ischemic stroke patients who underwent thrombectomy treatment of large vessel occlusions. Collateral status was determined using the cerebral collateral cascade (CCC) model, which comprises three components: arterial collaterals (Tan Scale) and venous outflow profiles (Cortical Vein Opacification Score) on CT angiography, and tissue-level collaterals (hypoperfusion intensity ratio) on CT perfusion. Quantitative ischemic lesion net water uptake (NWU) was used to determine edema growth between admission and follow-up non-contrast head CT (ΔNWU). Three groups were defined: CCC+ (good pial collaterals, tissue-level collaterals, and venous outflow), CCC− (poor pial collaterals, tissue-level collaterals, and venous outflow), and CCCmixed (remainder of patients). Primary outcome was ischemic lesion edema growth (ΔNWU). Multivariable regression models were used to assess the primary and secondary outcomes. Results 538 patients were included. 157 patients had CCC+, 274 patients CCCmixed, and 107 patients CCC− profiles. Multivariable regression analysis showed that compared with patients with CCC+ profiles, CCC− (β 1.99, 95% CI 0.68 to 3.30, P=0.003) and CCC mixed (β 1.65, 95% CI 0.75 to 2.56, P<0.001) profiles were associated with greater ischemic lesion edema growth (ΔNWU) after successful thrombectomy treatment. ΔNWU (OR 0.74, 95% CI 0.68 to 0.8, P<0.001) and CCC+ (OR 13.39, 95% CI 4.88 to 36.76, P<0.001) were independently associated with functional independence. Conclusion A comprehensive assessment of cerebral collaterals using the CCC model is strongly associated with edema growth and functional independence in acute stroke patients successfully treated by endovascular thrombectomy.

Background and purpose: Mechanical thrombectomy (MT) has proven to be the standard of care for patients with acute ischemic stroke due to large vessel occlusion (AIS‐LVO). However, high revascularization rates do not necessarily result in favorable functional outcomes. We aimed to investigate imaging biomarkers associated with futile recanalization, defined as unfavorable functional outcome despite successful recanalization in AIS‐LVO patients.Methods: A retrospective multicenter cohort study was made of AIS‐LVO patients treated by MT. Successful recanalization was defined as modified Thrombolysis in Cerebral Infarction score of 2b–3. A modified Rankin Scale score of 3–6 at 90 days was defined as unfavorable functional outcome. Cortical Vein Opacification Score (COVES) was used to assess venous outflow (VO), and the Tan scale was utilized to determine pial arterial collaterals on admission computed tomography angiography (CTA). Unfavorable VO was defined as COVES ≤ 2. Multivariable regression analysis was performed to investigate vascular imaging factors associated with futile recanalization.Results: Among 539 patients in whom successful recanalization was achieved, unfavorable functional outcome was observed in 59% of patients. Fifty‐eight percent of patients had unfavorable VO, and 31% exhibited poor pial arterial collaterals. In multivariable regression, unfavorable VO was a strong predictor (adjusted odds ratio = 4.79, 95% confidence interval = 2.48–9.23) of unfavorable functional outcome despite successful recanalization.Conclusions: We observe that unfavorable VO on admission CTA is a strong predictor of unfavorable functional outcomes despite successful vessel recanalization in AIS‐LVO patients. Assessment of VO profiles could help as a pretreatment imaging biomarker to determine patients at risk for futile recanalization.

BACKGROUND: Patient-specific factors associated with successful recanalization in mechanical thrombectomy (MT) have been evaluated for acute ischemic stroke with large vessel occlusion. However, MT for M2 occlusions is still a matter of debate, and predictors of successful and futile recanalization have not been assessed in detail. We sought to identify predictors of recanalization success in patients with M2 occlusions undergoing MT based on large-scale clinical data. METHODS: All patients prospectively enrolled in the German Stroke Registry (May, 2015 to December, 2021) were screened (N=13 082). Inclusion criteria for the complete case analysis were isolated M2 occlusions. Standard descriptive statistics and multivariable logistic regression analysis were used to identify factors associated with successful recanalization (Thrombolysis in Cerebral Infarction [TICI]≥2b), complete recanalization (TICI=3) and futile recanalization (TICI≥2b with 90-day modified Rankin Scale [mRS] score >2). RESULTS: One thousand two hundred ninety-four patients were included, thereof 439 (33.9%) with TICI=2b and 643 (49.7%) with TICI=3. Five hundred sixty-nine (44%) patients had good functional outcome (90-day mRS score ≤2). In multivariable logistic regression, general anesthesia (adjusted odds ratio [aOR], 1.47 [95% CI, 1.05–2.09]; P <0.05) was associated with higher probability of TICI≥2b while intraprocedural change from local to general anesthesia (aOR, 0.49 [0.26–0.95]; P <0.05) and higher pre-mRS (aOR, 0.75 [0.67–0.85]; P <0.001) lowered probability of successful recanalization. Futile recanalization was associated with higher age (aOR, 1.05 [1.04–1.07]; P <0.001), higher prestroke mRS (aOR, 3.12 [2.49–3.91]; P <0.001), higher NIHSS at admission (aOR, 1.11 [1.08–1.14]; P <0.001), diabetes (aOR, 1.96 [1.38–2.8]; P <0.001), higher number of passes (aOR, 1.29 [1.14–1.46]; P <0.001), and adverse events (aOR, 1.82 [1.2–2.74]; P <0.01). Higher Alberta Stroke Program Early CT Score (aOR, 0.85 [0.76–0.94]; P <0.01) and IV thrombolysis (aOR, 0.71 [0.52–0.97]; P <0.05) reduced risk of futile recanalization. CONCLUSIONS: In patients with M2 occlusions, successful recanalization was significantly associated with general anesthesia and low prestroke mRS, while intraprocedural change from conscious sedation to general anesthesia increased risk of unsuccessful recanalization, presumably caused by difficult anatomy and movement of patients in these cases. Futile recanalization was associated with severe prestroke mRS, comorbidity diabetes, number of passes and adverse events during treatment. IV thrombolysis reduced the risk of futile recanalization.

BACKGROUND: Recently, 3 randomized controlled trials provided high-level evidence that patients with large ischemic stroke achieved better functional outcomes after endovascular therapy than with medical care alone. We aimed to investigate whether the clinical benefit of endovascular therapy is associated with the number of recanalization attempts in extensive baseline infarction. METHODS: This retrospective multicenter study enrolled patients from the German Stroke Registry who underwent endovascular therapy for anterior circulation large vessel occlusion between 2015 and 2021. Large ischemic stroke was defined as an Alberta Stroke Program Early Computed Tomography Score of 3 to 5. The study cohort was divided into patients with unsuccessful reperfusion (Thrombolysis in Cerebral Infarction score, 0–2a) and successful reperfusion (Thrombolysis in Cerebral Infarction score, 2b/3) at attempts 1, 2, 3, or ≥4. The primary outcome was favorable functional outcome defined as modified Rankin Scale score of 0 to 3 at 90 days. Safety outcomes were symptomatic intracranial hemorrhage after 24 hours and death within 90 days. Multivariable logistic regression was used to identify independent determinants of primary and secondary outcomes. RESULTS: A total of 348 patients met the inclusion criteria. Successful reperfusion was observed in 83.3% and favorable functional outcomes in 36.2%. Successful reperfusion at attempts 1 (adjusted odds ratio, 5.97 [95% CI, 1.71–24.43]; P =0.008) and 2 (adjusted odds ratio, 6.32 [95% CI, 1.73–26.92]; P =0.008) increased the odds of favorable functional outcome, whereas success at attempts 3 or ≥4 did not. Patients with >2 attempts showed higher rates of symptomatic intracranial hemorrhage (12.8% versus 6.5%; P =0.046). Successful reperfusion at any attempt lowered the odds of death compared with unsuccessful reperfusion. CONCLUSIONS: In patients with large vessel occlusion and Alberta Stroke Program Early Computed Tomography Score of 3 to 5, the clinical benefit of endovascular therapy was linked to the number of recanalization attempts required for successful reperfusion. Our findings encourage to perform at least 2 recanalization attempts to seek for successful reperfusion in large ischemic strokes, while >2 attempts should follow a careful risk-benefit assessment in these highly affected patients. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03356392.

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.

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. Trial registration number NCT03356392.