Background: We investigated the platelet function in stroke patients treated with aspirin [acetylsalicylic acid (ASA)] for secondary stroke prevention during a follow-up period of 1 year.
Methods: In this prospective study 291 patients with first initiated aspirin therapy (300 mg/day) for secondary stroke prevention were included. Platelet aggregation measurements were performed 24 h, 3, 6, and 12 months after starting medication.
Results: Twenty-one of 291 patients (7.2%) were identified as primary ASA-non-responders (initial insufficient platelet inhibition) and 4.1% as secondary ASA-non-responders (insufficient platelet inhibition during follow-up). There were no significant differences between ASA-responders and ASA-non-responders concerning age, gender, risk factors, and stroke characteristics.
Conclusion: Aspirin resistance in stroke patients is not uncommon. The clinical usefulness of routine platelet function tests needs to be proved by further trials.