Related Experiment Video
Updated: Mar 22, 2026

A Fibrin-Enriched and tPA-Sensitive Photothrombotic Stroke Model
Published on: June 4, 2021
Aspirin resistance is associated with increased stroke severity and infarct volume
Mi Sun Oh1, Kyung-Ho Yu2, Ju-Hun Lee2
1From the Department of Neurology (M.S.O., K.-H.Y., J.-H.L., S.J., C.K., M.U.J., B.-C.L.), Hallym University College of Medicine, Hallym Neurological Institute; and Department of Biostatistics (J.L.), Korea University College of Medicine, South Korea. ssbrain@hallym.ac.kr iyyar@hallym.ac.kr.
Objectives:
To investigate whether aspirin resistance is associated with initial stroke severity and infarct volume, using diffusion-weighted imaging (DWI) in patients with acute ischemic stroke that occurred while taking aspirin.
Methods:
We studied a total of 310 patients who were admitted within 48 hours of acute ischemic stroke onset. All patients had been taking aspirin for at least 7 days before stroke onset. Aspirin resistance, defined as high residual platelet reactivity (HRPR) on aspirin treatment, was measured using the VerifyNow assay and defined as an aspirin reaction unit ≥550. Initial stroke severity was assessed using the NIH Stroke Scale (NIHSS) score. Infarct volume was measured using DWI.
Results:
HRPR occurred in 86 patients (27.7%). The initial NIHSS score (median [interquartile range]) was higher in patients with HRPR than in the non-HRPR group (6 [3-15] vs 3 [1-8], p < 0.001). DWI infarct volumes were also larger in the HRPR group compared to the non-HRPR group (5.4 [0.8-43.2] vs 1.7 [0.4-10.3], p = 0.002). A multivariable median regression analysis showed that HRPR was significantly associated with an increase of 2.1 points on the NIHSS (95% confidence interval 0.8-4.0, p < 0.001) and an increase of 2.3 cm(3) in DWI infarct volume (95% confidence interval 0.4-3.9, p < 0.001).
Conclusions:
Aspirin resistance is associated with an increased risk of severe stroke and large infarct volume in patients taking aspirin before stroke onset.
Related Concept Videos
Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
Anticoagulant Drugs: Low-Molecular-Weight Heparins
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu
Drug toxicity: Drug–Drug Interaction
Peripheral Artery Disease I: Introduction
Drug Toxicity: Risk factors

