Prevalence of Antiplatelet Resistance in Patients with Noncardioembolic Stroke
Samantha Cencer1, Asad Ahrar1, Malgorzata Miller1, Nadeem Khan1, Nabil Wees1, Laurel Packard1, Jiangyong Min1
1Department of Neurosciences, Corewell Health and Michigan State University
Objective:
This study was designed to evaluate the prevalence of inadequate antiplatelet to aspirin and clopidogrel in the setting of chronic use and presentation with primary or recurrent stroke.
Background:
Currently there is not sufficient data regarding the prevalence of resistance, or inadequate platelet function inhibition, with the use of antiplatelet therapy in patients with noncardioembolic stroke.
Design/Methods:
Patients who were taking aspirin, clopidogrel, or both at the time of presentation for stroke were selected in this study. Those with confirmed stroke on MRI or clinically determined TIA and age >18 years were included. A standard laboratory test- VerifyNow aspirin or P2Y12 assay was utilized to assess the responsiveness to the platelet inhibitors. A total of 158 patients were identified, 52 presenting with primary stroke and 106 with recurrent stroke. Data was analyzed using Chi-squared or Fishers’ Exact as well as T-test analysis.
Results:
Of the primary stroke population, 4% of patients demonstrated resistance to aspirin and 29% to clopidogrel. Of the patients presenting with recurrent stroke, 13% demonstrated resistance to aspirin and 38% to clopidogrel. The data also suggests increased resistance to aspirin and clopidogrel in Caucasians compared to minorities with 11% versus 0.8% in regard to aspirin and 32% versus 1% to clopidogrel. Additionally, this study demonstrated 16% resistance to aspirin in males compared to 0.7% in females, and 12% compared to 38% respectively regarding resistance to clopidogrel. No difference of inactivity to either aspirin or clopidogrel was detected between patients with small or large vessel disease.
Conclusions:
The present result suggests a sizeable portion of the population has inefficacious activity in the setting of certain antiplatelet agents. Additionally, sex and ethnicity differences in responsiveness to aspirin or clopidogrel have been noted. Further studies of larger scale will need to apply this information to pursue individualized treatment.