Toward a Better Understanding of Patient Selection for Thrombectomy in Patients With Large Ischemic Core

BACKGROUND AND OBJECTIVES: The benefit of thrombectomy in general for patients with large core strokes has been established across multiple trials, although inclusion criteria for the procedure seem quite broad across heterogeneous groups. Understanding subgroups that benefit optimally vs those in which thrombectomy may fall in the realm of futility is lacking. METHODS: A prospectively maintained database was queried for thrombectomy for acute ischemic stroke with Alberta Stroke Program Early Computed Tomography Score of ≤5 from 2021 to 2025. Study outcomes at 90 days included functional independence (modified Rankin Scale [mRS] 0-2), independent ambulation (mRS 0-3), and mortality. Stratified results classified patients into potential categories, based on probability curves and heatmaps across age, last-known-well (LKW), and National Institute of Health Stroke Scale (NIHSS) score. Impact of the category was adjusted in logistic regression models. RESULTS: Of 1458 patients who underwent thrombectomy, 80 (5.5%) were for acute ischemic stroke of Alberta Stroke Program Early Computed Tomography Score ≤5, with a modified Treatment in Cerebral Infarction ≥2b in 89%. The symptomatic hemorrhage rate was 6.3%. At 90 days, 10% of patients were mRS 0 to 2, 30% mRS 0 to 3, and mortality was 34%. Patients were classified into 3 categories. Category 1 (57% of cases) were aged 75 years and younger with NIHSS <20 or LKW ≤12 hours. Ninety days after thrombectomy, 18% of these patients were mRS 0 to 2, 47% mRS 0% to 3%, and 18% died. Category 2 (27% of cases) were aged 75 years and younger with NIHSS ≥20 and LKW >12 hours, or older than 75 with LKW ≤12 hours. There was a 0% mRS 0 to 2 rate in this subgroup; 14% were mRS 3%, and 52% died. Category 3 patients (16% of patients) were aged older than 75 years with LKW >12 hours. No patient was mRS 0 to 3 at follow-up, and 62% had died. A higher risk category was associated with a decreased probability of mRS 0 to 3 (adjusted odds ratio 0.14, P = .01) and higher mortality (adjusted odds ratio 2.7, P = .03) in multiple regression models. CONCLUSION: Patient age, presenting NIHSS and last known well time are significant determinants of outcome after thrombectomy for patients with large core stroke.