A 2-point difference of NIHSS as a predictor of acute ischemic stroke outcome at 3 months after thrombolytic therapy

A good functional response at 24 h from an intravenous recombinant tissue plasminogen activator (rtPA) treatment is associated with 3-month ischemic stroke outcome. The criterion for 24 -h neurological improvement is varied from 4 to 8 point the National Institutes of Health Stroke Scale (NIHSS) score reduction. This study aimed to evaluate the smaller difference of the NIHSS at 2 points on long term functional status.

The inclusion criteria were adult patients diagnosed as acute ischemic stroke and received the rtPA treatment. There were two stroke outcomes comprised of immediate 24 -hs and 3 month long term outcomes. Favorable 24 -h outcome defined by improvement of the NIHSS at 24 h after the rtPA treatment at least 2 points or equal to 0. At 3 months, the outcome was evaluated by using the modified Rankin scale (mRS). The mRS of 0-1 and 2-6 defined as favorable and poor outcome, respectively. Factors associated with poor outcomes at 24 h and 3 months after the rtPA treatment were calculated by logistic regression analysis.

There were 618 patients met the study criteria. Of those, 403 patients (65.2 %) received the rtPA treatment at the tertiary care hospital. At 24 h after the rtPA treatment, 163 patients (26.38 %) had poor outcome. After adjusted, age and atrial fibrillation had adjusted odds ratios (95 % confidence interval) for poor outcome at 24 h after the rtPA treatment of 1.026 (1.009, 1.043) and 1.725 (1.119, 2.658). At 3 months after the rtPA treatment, the poor outcome at 24 h after rtPA treatment had the highest adjusted odds ratio at 42.876 (95 % confidence interval of 21.500, 85.501).

The NIHSS differences of 2 points at 24 -h after the rtPA treatment from baseline may be an additional tool to predict the 3-month functional outcome of acute ischemic stroke patients.