Abstract WP43: ‘Clinical-Diffusion Mismatch’ Triage Criteria at 8-24 Hours from Symptom Onset Identifies 4% of Stroke Patients for Potential Intervention
Background: ‘Clinical-diffusion mismatch’ (CDM) criteria may identify ischemic stroke (IS) patients with salvageable penumbra, and is intended for triage in a planned prospective trial of acute stroke intervention for patients presenting between 8 and 24 hours. For this study, CDM is defined as a National Institutes of Health Stroke Scale Score (NIHSSS) ≥8 and diffusion weighted imaging (DWI) stroke volume of ≤25 mL3 using a modified ‘ABC/2’ criteria, which has previously been validated against planimetric imaging and shown to have excellent inter-rater reliability. We sought to determine the percentage of potential patients who may be screened for enrollment on this basis in 2 urban teaching hospitals which each receive >200 stroke patients per year.
Methods: We identified all IS admissions from our Get with the Guidelines database from 1/1/10-12/31/10. We then abstracted those arriving within 8 to 24 hours of symptom onset and then, of this subset, those who had an initial NIHSSS ≥8. To determine those meeting radiographic criteria, we measured stroke volume on the admission head computed tomogram (CT) using the unadjusted ABC/2 formula. As CT is known to have a 60% sensitivity for IS compared with DWI within 12 hours, we estimated that only 60% of the patients from the above calculation might still have lesion volumes ≤25mL3 on DWI.
Results: A total of 588 IS patients were admitted in 2010. Of these, 162 patients presented within 8-24 hours. NIHSSS were ≥8 in 41 of whom 28 had lesions ≤25mL3. Considering 60% of these would remain valid on DWI, would leave approximately 17 patients (2.6%). Incomplete data led to attrition at each step; applying the same percentages at each recruitment step to those lost yields 9 patients, for an overall potential recruitment of 26 (4.4%, table).
Conclusion: We conservatively estimate that in 1 year, 4% of IS patients within 8-24 hours demonstrate a CDM. These data are important for trialists and funding agencies planning studies using CDM criteria.
- © 2012 by American Heart Association, Inc.