Background: and Purpose Whether perfusion-diffusion mismatch modifies treatment effect of mechanical thrombectomy (MT) for large strokes is poorly known. To address this question, we conducted a post hoc secondary analysis of the Large Stroke Therapy Evaluation (LASTE) randomized controlled trial (RCT). Methods: The LASTE RCT compared MT plus best medical treatment (BMT) to BMT alone in patients with large infarct (Alberta Stroke Program Early CT Score 0–5) in the 0–7-hour timewindow. This secondary analysis was restricted to patients with available baseline MR perfusionweighted imaging. We investigated the potential heterogeneity of MT treatment according to the presence of perfusion-diffusion mismatch, defined as a mismatch ratio ≥1.2, calculated as the time-to-maximum >6 seconds cerebral volume divided by ischemic core volume. The primary outcome was better functional outcome (favorable shift in the distribution of modified Rankin Scale [mRS] at 90 days, analyzed using generalized odds ratio [GenOR]). Results: A total of 102/324 patients were included, among whom 55 (54%) had a perfusiondiffusion mismatch. No significant treatment effect heterogeneity by diffusion-perfusion mismatch was observed for the primary outcome (GenOR for better functional outcome: 1.70 [95% confidence interval, CI, 0.95 to 3.05] and 1.04 [95% CI, 0.57 to 1.87] in patients with and without mismatch, respectively; ratio of GenORs: 1.63 [95% CI, 0.71 to 3.74]; P for heterogeneity=0.24) or for the secondary efficacy and safety outcomes. Conclusions Our study found no evidence of heterogeneity of treatment effect with respect to benefit or safety in patients with unrestricted infarct size at baseline treated with MT by presence of perfusion-diffusion mismatch. An individual participant-data meta-analysis of RCT is needed for definitive conclusions.

Background: and Purpose In patients with ischemic stroke and isolated cervical internal carotid artery occlusion (c-ICA-O), endovascular therapy (EVT) can improve cerebral perfusion. To maintain vessel patency, EVT is frequently combined with carotid artery stenting (CAS). We assessed the efficacy and safety of emergent CAS during EVT for isolated c-ICA-O. Methods: This retrospective multinational cohort study (42 centers) included consecutive patients who underwent EVT for isolated c-ICA-O within 24 hours from the time last seen well. Patients who underwent emergent CAS were compared with those who did not. Co-primary outcomes were c-ICA vessel patency and symptomatic intracerebral hemorrhage (sICH) 24 hours post-EVT. Secondary outcomes included any intracerebral hemorrhage (ICH) at 24 hours and disability at 3 months (modified Rankin Scale [mRS] shift). Outcomes were adjusted using inverse probability of treatment weighting. Results: Of 317 patients (mean age, 68.6 years [standard deviation, 12.9]; median National Institutes of Health Stroke Scale 11 [interquartile range, 6–17]; 26.8% female), 219 (69.1%) underwent CAS, whereas 98 (30.9%) did not. At 24 hours, vessel patency was more common after CAS (83.5% vs. 40.7%; adjusted odds ratio [aOR], 9.45; 95% confidence interval [CI], 4.91–18.17); sICH rates did not differ (2.3% vs. 3.1%; aOR, 0.92; 95% CI, 0.18–4.73). Any ICH was more common after CAS (19.3% vs. 9.3%; aOR, 2.50; 95% CI, 1.12–5.60). CAS was not associated with mRS at 3 months (adjusted common odds ratio, 0.98; 95% CI, 0.62–1.56). Conclusions In patients undergoing EVT for isolated c-ICA-O, emergent CAS was technically effective and reasonably safe. More frequent vessel patency in patients who underwent CAS did not translate into improved functional outcome at 3 months.