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Updated: Apr 17, 2026
06:01
A Thrombotic Stroke Model Based On Transient Cerebral Hypoxia-ischemia
Published on: August 18, 2015
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Pathophysiologic, rather than laboratory-defined resistance drives aspirin failure in ischemic stroke
Nergiz Agayeva1, Levent Gungor2, Mehmet Akif Topcuoglu1
1Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.
Summary
Clinical aspirin resistance in ischemic stroke is often due to underlying causes, not just poor platelet inhibition. Understanding these pathophysiologic factors is key to effective treatment.
Area of Science:
- Neurology
- Cardiology
- Pharmacology
Background:
- Ischemic strokes occur despite aspirin use, termed clinical aspirin resistance.
- Laboratory tests assess in vitro platelet reactivity to aspirin.
- Discrepancies exist between clinical and lab-defined aspirin resistance, possibly due to stroke causes.
Purpose of the Study:
- To evaluate laboratory aspirin resistance in ischemic stroke patients using the VerifyNow Aspirin Assay.
- To compare clinical and laboratory resistance, and identify contributing stroke etiologies.
Main Methods:
- Prospective evaluation of 78 ischemic stroke patients on aspirin using VerifyNow Aspirin Assay.
- Comparison of demographic, clinical features, and stroke etiology with aspirin-naive patients (n=257).
- Validation in a separate cohort.
Main Results:
- Laboratory evidence of insufficient platelet inhibition found in 21% of patients with clinical aspirin resistance.
- 38% had stroke etiologies known to be poorly responsive to aspirin.
- Laboratory resistance accounted for the ischemic event in only 15% (9% in validation cohort).
Conclusions:
- Laboratory aspirin resistance due to insufficient platelet inhibition is uncommon.
- Pathophysiologic resistance, related to stroke etiology, is a major cause of clinical aspirin resistance in ischemic stroke.
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