Simple clinical predictors of stroke outcome based on National Institutes of Health Stroke Scale score during 1‐h recombinant tissue‐type plasminogen activator infusion

Background and purpose An index for predictors of stroke outcome was determined based on the National Institutes of Health Stroke Scale ( NIHSS ) scores during 1‐h intravenous administration of recombinant tissue‐type plasminogen activator (rt‐ PA ). Methods Stroke patients with baseline NIHSS score ≥8 and occlusion at the internal carotid or middle cerebral arteries ( ICA , MCA ) were retrospectively studied from a prospective single‐center registry. NIHSS scores and inverse change from baseline scores (Δ NIHSS ) were assessed at 30 min and 1 h after rt‐ PA infusion. Patients were divided into two groups according to arterial occlusion sites: group P, ICA or proximal M1; and group D, distal M1 or M2. A modified Rankin Scale score of 2–6 at 3 months was defined as an unfavorable outcome. Results In all 108 patients, the cutoff NIHSS score predicting unfavorable outcome was ≥12 and cutoff Δ NIHSS scores were ≤2 at both 30 min and 1 h. In group P ( n  = 36), the cutoff NIHSS score was ≥14 at both 30 min and 1 h and cutoff Δ NIHSS scores were ≤1 at 30 min and ≤2 at 1 h. Unfavorable outcome was seen in all patients with NIHSS 1 h ≥ 14, Δ NIHSS 30 min ≤ 1 and Δ NIHSS 1 h ≤ 2. In group D ( n  = 72), the cutoff NIHSS scores were ≥12 at both 30 min and 1 h, and cutoff Δ NIHSS scores were ≤2 at 30 min and ≤7 at 1 h; 90% of patients with unfavorable outcome showed Δ NIHSS 1 h ≤ 7. Conclusion NIHSS and Δ NIHSS during 1‐h rt‐ PA infusion seemed predictive of 3‐month outcome when the site of arterial occlusion was identified prior to rt‐ PA .