Long-Term Prediction of Functional Outcome After Stroke Using the Alberta Stroke Program Early Computed Tomography Score in the Subacute Stage

Stroke patients who arrive at hospital more than 24 hours after symptom onset could benefit from a simple means of assessing long-term prognosis in this subacute stage. We evaluated whether clinical factors along with ischemic injury assessed subacutely using the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) had predictive value for functional independence after stroke. Computed tomography (CT) scans obtained >= 2 days after first-ever ischemic stroke were scored independently and retrospectively by 3 stroke neurologists using the ASPECTS. Functional outcome was measured using the Functional Independence Measure, which assesses the amount of caregiver assistance required by patients during daily activities. Multiple linear regression was used to develop a predictive model for functional prognosis at 1 month, 3 months, and 1 year poststroke. For our 55 patients, CT scanning was done on average 4 days poststroke. The interrater agreement for subacute ASPECTS was excellent, with a kappa-weighted value of 0.90. Lesions involving the frontal and superior parietal ASPECTS regions were significant predictors of lower Functional Independence Measure scores at all 3 time points studied. In combination with such factors as age, marital status, and the severity of initial neurologic deficit, a subacute ASPECTS score >5 had significant predictive value for greater functional independence at 3 months (R-2 = 0.701; P<.001) and 1 year (R-2 = 0.528; P<.001) poststroke. Our data indicate that in the subacute stage, ASPECTS is reliable and can help predict which patients may be likely to regain functional independence up to 1 year after sustaining ischemic stroke.