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.

The benefits of mechanical thrombectomy (MT) for patients with acute ischemic stroke (AIS) and a large ischemic core (LIC) at presentation are uncertain. We aimed to obtain up-to-date aggregate estimates of the outcomes following MT in patients with volumetrically assessed LIC. We conducted a Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)-conformed, PROSPERO-registered, systematic review and meta-analysis of studies that included patients with AIS and a baseline LIC treated with MT, reported ischemic core volume quantitatively, and included patients with a LIC defined as a core volume ≥50 mL. The search was restricted to studies published between January 2015 and June 2020. Random-effects-meta-analysis was used to assess the effect of MT on 90-day unfavorable outcome (i.e., modified Rankin Scale [mRS] 3–6), mortality, and symptomatic intracranial hemorrhage (sICH) occurrence. Sensitivity analyses were performed for imaging-modality (computed tomography-perfusion or magnetic resonance-diffusion weighted imaging) and LIC-definition (≥50 or ≥70 mL). We analyzed 10 studies (954 patients), including six (682 patients) with a control group, allowing to compare 332 patients with MT to 350 who received best-medical-management alone. Overall, after MT the rate of patients with mRS 3–6 at 90 days was 74% (99% confidence interval [CI], 67 to 84; Z-value=7.04; I2=92.3%) and the rate of 90-day mortality was 36% (99% CI, 33 to 40; Z-value=–7.07; I2=74.5). Receiving MT was associated with a significant decrease in mRS 3–6 odds ratio (OR) 0.19 (99% CI, 0.11 to 0.33; P<0.01; Z-value=–5.92; I2=62.56) and in mortality OR 0.60 (99% CI, 0.34 to 1.06; P=0.02; Z-value=–2.30; I2=58.72). Treatment group did not influence the proportion of patients experiencing sICH, OR 0.96 (99% CI, 0.2 to 1.49; P=0.54; Z-value=–0.63; I2=64.74). Neither imaging modality for core assessment, nor LIC definition influenced the aggregated outcomes. Using aggregate estimates, MT appeared to decrease the risk of unfavorable functional outcome in patients with a LIC assessed volumetrically at baseline.

The benefits of mechanical thrombectomy (MT) for patients with acute ischemic stroke (AIS) and a large ischemic core (LIC) at presentation are uncertain. We aimed to obtain up-to-date aggregate estimates of the outcomes following MT in patients with volumetrically assessed LIC. We conducted a Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA)-conformed, PROSPERO-registered, systematic review and meta-analysis of studies that included patients with AIS and a baseline LIC treated with MT, reported ischemic core volume quantitatively, and included patients with a LIC defined as a core volume ≥50 mL. The search was restricted to studies published between January 2015 and June 2020. Random-effects-meta-analysis was used to assess the effect of MT on 90-day unfavorable outcome (i.e., modified Rankin Scale [mRS] 3–6), mortality, and symptomatic intracranial hemorrhage (sICH) occurrence. Sensitivity analyses were performed for imaging-modality (computed tomography-perfusion or magnetic resonance-diffusion weighted imaging) and LIC-definition (≥50 or ≥70 mL). We analyzed 10 studies (954 patients), including six (682 patients) with a control group, allowing to compare 332 patients with MT to 350 who received best-medical-management alone. Overall, after MT the rate of patients with mRS 3–6 at 90 days was 74% (99% confidence interval [CI], 67 to 84; Z-value=7.04; I2=92.3%) and the rate of 90-day mortality was 36% (99% CI, 33 to 40; Z-value=–7.07; I2=74.5). Receiving MT was associated with a significant decrease in mRS 3–6 odds ratio (OR) 0.19 (99% CI, 0.11 to 0.33; P<0.01; Z-value=–5.92; I2=62.56) and in mortality OR 0.60 (99% CI, 0.34 to 1.06; P=0.02; Z-value=–2.30; I2=58.72). Treatment group did not influence the proportion of patients experiencing sICH, OR 0.96 (99% CI, 0.2 to 1.49; P=0.54; Z-value=–0.63; I2=64.74). Neither imaging modality for core assessment, nor LIC definition influenced the aggregated outcomes. Using aggregate estimates, MT appeared to decrease the risk of unfavorable functional outcome in patients with a LIC assessed volumetrically at baseline.

No abstract available.
Humans ; Thrombectomy

BACKGROUND AND PURPOSE: A long clot, defined by a low (0-6) clot burden score (CBS) assessed by T2*-MR sequence, is associated with worse clinical outcome after intravenous thrombolysis (IVT) for acute ischemic stroke than is a small clot (CBS, 7-10). The added benefit of mechanical thrombectomy (MT) might be higher in patients with long clot. The aim of this pre-specified post hoc analysis of the THRombectomie des Artères CErebrales (THRACE) trial was to assess the association between T2*-CBS, successful recanalization and clinical outcome. METHODS: Of 414 patients randomized in the THRACE trial, 281 patients were included in this analysis. Associations between T2*-CBS and clinical outcome on the modified Rankin Scale (mRS) at 3 months were tested. RESULTS: High T2*-CBS, i.e., small clot, was associated with a shift toward better outcome on the mRS; proportional odds ratio (POR) per point CBS was 1.19 (95% confidence interval [CI], 1.05 to 1.34) in the whole population, 1.34 (95% CI, 1.13 to 1.59) in IVT group, and 1.04 (95% CI, 0.87 to 1.23) in IVTMT group. After adjustment for baseline prognostic variables, the effect of the full scale T2*-CBS was not statistically significant in the whole population and for the IVTMT group but remains significant for the IVT group (POR, 1.32; 95% CI, 1.11 to 1.58). CONCLUSIONS: A small clot, as assessed using T2*-CBS, is associated with improved outcome and may be used as a prognostic marker. Despite the worst outcome with long clot, the relative benefit of MT over IVT seemed to increase with low T2*-CBS and longer clot.
Humans ; Magnetic Resonance Imaging ; Odds Ratio ; Stroke ; Thrombectomy ; Thrombosis