Background: Usually early infarct signs on imaging take a few hours to develop in ischemic stroke. There may be a subset of patients manifesting early infarct signs on imaging hyperacutely.
Objective: To determine the prevalence and factors associated with very early infarct signs on ASPECTS among patients with cerebral ischemia who were imaged <90 minutes after symptom onset.
Methods: Subjects participating in the NIH Field Administration of Stroke Therapy- Magnesium (FAST-MAG) phase 3 clinical trial with a final diagnosis of cerebral ischemia (TIA or Stroke) and initial imaging performed <90 minutes from last known well time (LKWT) were included. ASPECTS was graded by a neuroradiologist (JPV) blinded to all clinical information. Individual subjects were characterized as having no early ischemic changes (ASPECTS 10) vs. early ischemic changes (ASPECTS 0-9). We describe the prevalence of early ischemic signs in this prospectively enrolled cohort, clinical factors associated with early ischemic changes as well as outcomes.
Results: There were 566 cases imaged a mean of 71 (SD 11) minutes after LKWT. Mean age was 69 (SD 13), 43% women, 93% ischemic stroke, 7% TIA, median emergency department NIHSS 8 (IQR 3-16), median ASPECTS score of 10 (IQR 7-10, range 1-10). There were 200 cases with early ischemic findings (35%). Early ischemic changes were not related to age, blood pressure, history of hypertension, diabetes, dyslipidemia, coronary artery disease, or time to imaging (71 vs. 71 mins). Early ischemic changes were more commonly noted in women (50% vs. 39%, p=0.015) and associated higher presenting NIHSS (14 [IQR 7-20] vs 5 [IQR 2-11], p<0.001). The presence of any hyperacute ischemia change was associate with worse 90-day outcome (modified Rankin score 3 [IQR 1-5] vs 1 [IQR 0-3, p<0.001).
Conclusions: Early ischemic changes were noted on about 1/3rd of imaging obtained <90 minutes after symptom onset. The presence of hyperacute ischemic changes is associated with more severe stroke and poor clinical outcomes.