Discussion
Aspirin is well recognized as an effective antiplatelet drug for secondary prevention in stroke patients. However, despite aspirin treatment, a number of patients experience recurrent ischemic stroke. The term “aspirin resistance” has evolved to describe the failure of aspirin to produce suppression of platelet aggregation as assessed by platelet function assays(24). There is increasing evidence that laboratory aspirin resistance is clinically important. Gum et al(23) found a significant correlation between aspirin resistance as measured by optical platelet aggregation and the increased risks of stroke, myocardial infarction, and death. However, the clinical implications of a semi- response to aspirin have not been sufficiently studied. The previous study showed that the rate of ischemic stroke in aspirin resistance and aspirin semi- responsiveness groups was significantly higher than that of the aspirin non-resistance group(25). This finding might indicate that aspirin semi-responsiveness was associated with an increased risk of ischemic stroke