Rapidly improving stroke symptoms: a pilot, prospective study

Abstract

Background: Rapidly improving stroke symptoms (RISSs) are a controversial exclusion for intravenous recombinant tissue plasminogen activator (rt-PA) for acute ischemic stroke (AIS). We estimated the frequency of 4 prespecified RISS definitions and explored their relationship to clinical outcome.

Methods: Pilot, prospective study of AIS patients admitted within 4.5 hours of symptom onset. Serial assessments using National Institute of Health Stroke Scale (NIHSS) were performed every 20 ± 5 minutes until a rt-PA treatment decision was made, independent of the study. Improvement was calculated as the difference between baseline NIHSS and treatment decision NIHSS. RISS was defined as a 4-point or greater improvement, 25% or greater, 50% or greater, and according to the previously reported TREAT (The Re-examining Acute Eligibility for Thrombolysis) criteria. Unfavorable outcome was defined as modified Rankin Scale score more than 1 at 90 days after stroke. Logistic regression determined if RISS definition(s) related to the outcome.

Results: Fifty patients with AIS were enrolled: mean age 65 years; median baseline NIHSS score 5 (interquartile range, 2-11). RISS frequencies were 10%-22% based on definition. Median treatment decision NIHSS score is 5 (interquartile range, 2-9). Twenty-three (46%) patients received rt-PA. None of the 3 non-TREAT RISS definitions was independently associated with the outcome. Five of fifty (10%) were RISS according to the TREAT criteria, all 5 had good outcome without rt-PA.

Conclusions: A Serial NIHSS assessment before treatment decision is feasible and may help determine the frequency and magnitude of RISS. This is the first prospective estimate of RISS frequency and outcome according to various prespecified definitions. The TREAT RISS frequency as a more restrictive definition may better predict good outcome of RISS in future, larger studies.

Keywords: Acute stroke; National Institutes of Health Stroke Scale; minor stroke; rapidly improving stroke symptoms; thrombolysis; tissue plasminogen activator.