Abstract WP390: Stroke Severity Threshold For Acute Stroke Trials
Introduction: The planning of a thrombolysis trial presents a typical clinical research problem: what lower threshold of baseline stroke severity will identify an informative population? Applying representative trial entry criteria for patients lodged within Virtual International Stroke Trials Archive (VISTA), we undertook to identify a lower threshold for baseline (b)NIHSS at which thrombolysis was associated with improved outcomes in all patients, and in patients with left or right hemisphere stroke.
Methods: We selected patients with an age-range of 18-85 and baseline (b)NIHSS 4-24. Outcomes were defined as mRS 0-1 (Excellent Functional Outcome), mRS 0-2 (Good Functional Outcome) and either NIHSS improvement of 8 points, or NIHSS of 0-1, or both, on day 90 (Neurological Outcome). We undertook age-adjusted comparison of outcomes between thrombolysed and non-thrombolysed patients that belonged to each bNIHSS level.
Results: Functional and neurological outcome data were available for 7811 patients and 7696 patients respectively. Thrombolysed patients were younger than non-thrombolysed patients (66.7 ± 12.4 vs. 68.7 ± 11.5, p<0.001, N=7811). bNIHSS was greater among thrombolysed patients compared to non-thrombolysed patients (median 13 vs.12, p<0.0001, N=7811). OR for outcomes after thrombolysis were >1 for b-NIHSS ≥8 in all patients, and in patients with right and left hemisphere stroke. Stroke laterality significantly interacted with b-NIHSS, and with thrombolysis, in a prediction model of functional outcomes (p<0.05), and OR for all outcome measures were greater for left hemisphere stroke (p<0.05).
Conclusions: Outcomes were consistently improved among patients whose bNIHSS was ≥8, with inconsistency or neutral findings at lower NIHSS scores.
- © 2012 by American Heart Association, Inc.