Stroke Study Evaluates Predictive Value of CT Scan and Time to Recanalization

January 1, 2011—In Stroke, Mayank Goyal, MD, et al published findings from an evaluation of the association of a favorable initial noncontrast computed tomography (CT) scan and a short time to recanalization in predicting good outcomes (2011;42:93–97).

As detailed in Stroke, data were from the Penumbra Pivotal Stroke Trial (Penumbra, Inc., Alameda, CA), which had reported a 25% good outcome (modified Rankin scale score 2) despite an 81% recanalization rate. Baseline scans were evaluated by two experienced readers blinded to outcomes using ASPECTS (Alberta Stroke Program Early CT Score). 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.

The investigators reported that median baseline NIHSS (National Institutes of Health Stroke Scale) score 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%; relative risk [RR], 3.3; 95% confidence interval, 1.6–6.8; P = .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 = .06).

The investigators concluded that patients with baseline CT ASPECTS score ≤ 4 do not benefit from recanalization. They noted that fast recanalization may benefit patients with evident damage on the CT scan (ASPECTS score > 4) and that overall, patients benefit the most with early recanalization and a favorable baseline CT scan (ASPECTS score > 7).