Abstract WMP61: TWOACES: TIA Work-up As Outpatient, Assessment Of Clinical Efficacy And Safety
Background: Much controversy exists as to the appropriate triage of acute TIA patients. One commonly used tool is the ABCD2 score. This tool is helpful for patients at low risk (score of 0-3) or high risk (score of 6-7) of stroke, but leaves a large moderate risk population (score of 4-5) for whom no clear guidance can be given. As previous studies have found large artery atherosclerosis to be a potent risk factor for stroke after TIA, we attempted to further delineate low and high risk TIA populations with the addition of non-invasive arterial imaging.
Methods: All patients referred to the Stanford Stroke Service for possible TIA within 72 hours of symptom onset between July 2007 and February 2010, and all patients referred to the Highland Park Stroke Service for possible TIA within 72 hours of symptom onset after October 2009 were screened for enrollment in this observational study. 406 patients were invited to enroll, 5 refused. Of the 401 enrolled, follow-up was obtained in 398 patients. Patients were placed into two groups: 1) ABCD2 scores of 0-3 or 4-5 AND no sign of hemodynamically significant stenosis (<50%) "Low Risk Group"; and 2) those with ABCD2 scores of 6-7 or 4-5 AND hemodynamically significant stenosis (≥50%) "High Risk Group". Non-invasive arterial imaging included CTA, MRA, and Carotid US - all chosen by the treating physician. 30 day stroke rates with 95% CIs were recorded.
Results: Of the 398 patients in whom follow-up data was obtained, 340 (85.4%) fell into the “Low Risk Group”. Within that group, the stroke rate at 30 days was 1.76% (6 strokes, 95% CI 0.72-3.89%). Within the “High Risk Group”, the stroke rate at 30 days was 5.17% (3 strokes, 95% CI 1.21-14.7%). The overall stroke rate was 9/398 (2.26%, 95% CI 1.13-4.31%).
Conclusions: In our observational study we continue to find that the overall 30 day stroke rate after TIA was quite low (2.26%). The percentage of all TIA patients falling into the “Low Risk Group” was quite high (85.4%), and these patients had a particularly low rate of stroke at 30 days. Given the high number of “Low Risk” patients and the low rate of stroke in that group at 30 days, the vast majority of TIA patients could likely be safely evaluated in a rapid outpatient setting provided that the treating physician is confident of the diagnosis.
- © 2012 by American Heart Association, Inc.