VANCOUVER, BC—Individuals who used aspirin preceding a stroke display milder acute ischemic stroke severity, independent of acute infarct volume on diffusion-weighted MRI (DWI), analysis of a retrospective database presented at the 68th AAN Annual Meeting has found.

As a primary and secondary prevention agent, aspirin is known to reduce serious vascular events and prevent ischemic stroke. However, “studies on aspirin’s effect on stroke severity are conflicting,” noted Sarah Nelson, MD, of the J. Philip Kistler Stroke Research Center and the Department of Neurology at Massachusetts General Hospital, Boston, MA, and colleagues.

They hypothesized that in patients with acute ischemic stroke, “presenting stroke severity as measured by baseline National Institutes of Health Stroke Scale (NIHSS) is affected by antecedent aspirin use independent of acute infarct size” on DWI.

To test this hypothesis, they conducted a retrospective analysis of 610 patients with acute ischemic stroke who had hospital admission brain MRIs available for volumetric analysis of acute infarct size. A total of 241 (39.5%) patients had used aspirin prior to their stroke.

Users of antecedent aspirin were found to be significantly older, a mean age of 68.3 years, compared to 62.6 years for non-users (P<0.0001).

On univariate analysis, predictors of presenting stroke severity were antecedent aspirin use (odd ratio [OR] 0.59; 95% confidence interval [CI]: 0.44-0.80; P=0.0005), history of atrial fibrillation (AF; OR 3.06; 95% CI: 2.01–4.64; P<0.0001), DWI volume (OR 1.06; 95% CI: 1.05-1.08; P<0.0001), initial systolic blood pressure (SBP; OR 1.01; 95% CI: 1.00–1.01; P=0.041), admission plasma glucose level (R 1.00; 95% CI: 1.00–1.01; P=0.0027), and stroke subtype (OR 0.83; 95% CI: 0.76–0.91; P<0.0001).

On multivariable analysis, antecedent aspirin use (OR 0.49; 95% CI: 0.35–0.67; P<0.0001), history of AF (OR 2.51; 95% CI: 1.54–4.11; P<0.0002), DWI volume (OR 1.06; 95% CI: 1.04–1.07; P<0.0001), SBP (OR 1.01; 95% CI: 1.00–1.01; P=0.038), and plasma glucose level (OR 1.00; 95% CI: 1.00–1.01; P=0.0095) remained independent predictors of presenting stroke severity on the NIHSS.

Variables that did not predict for stroke severity included age, male sex, hypertension, hyperlipidemia, diabetes mellitus, coronary artery disease, prior ischemic stroke, prior transient ischemic attack, use of tobacco or alcohol, or diastolic blood pressure.

“Our data support known associations between hyperglycemia, AF, and larger DWI volume and greater baseline stroke severity,” Dr. Nelson reported. “Further studies to confirm our findings, clarify the mechanism(s) by which aspirin is linked to stroke severity, and elucidate which populations may benefit from routine use of aspirin are needed,” she concluded.