Effect of Baseline CT Scan Appearance and Time to Recanalization on Clinical Outcomes in Endovascular Thrombectomy of Acute Ischemic Strokes

BACKGROUND AND PURPOSE: the Penumbra Pivotal Stroke Trial reported a 25% good outcome (modified Rankin scale score ≤ 2) despite an 81% recanalization rate. We evaluated the association of a favorable initial noncontrast CT and a short time to recanalization in predicting good outcome. METHODS: data were from the Penumbra Pivotal Stroke Trial. Baseline scans were evaluated by 2 experienced readers blinded to outcomes using ASPECTS. ASPECTS scores were dichotomized into >7 and ≤ 7 for primary analysis. Data on degree of recanalization based on thrombolysis in myocardial infarction scores, stroke onset to recanalization, and CT to recanalization times were obtained. Primary outcome was modified Rankin scale score ≤ 2 at 3 months. RESULTS: median baseline NIHSS was 18 (range, 8-34) and median baseline ASPECTS score was 6 (range, 0-10); 81.2% achieved recanalization (thrombolysis in myocardial infarction, 2-3) and (27.7%) achieved good outcome. Good outcome was significantly higher in the ASPECTS score >7 group when compared to the ASPECTS score ≤ 7 group (50% vs 15%; RR, 3.3; 95% CI, 1.6-6.8; P=0.0001). No patient with an ASPECTS score ≤ 4 (n=28) or without recanalization (n=16) had a good outcome. There was an interaction between baseline ASPECTS score (>7 and ≤ 7) and onset to recanalization time (≤ 300 minutes and >300 minutes) in predicting good outcome (P=0.06). CONCLUSIONS: patients with baseline CT ASPECTS score ≤ 4 do not benefit from recanalization. Fast recanalization may benefit patients with evident damage on the CT scan (ASPECTS score >4). Overall, patients benefit the most with early recanalization and a favorable baseline CT scan (ASPECTS score >7).