The purpose of this retrospective study was to determine if whole blood platelet aggregation testing (WBA) and pharmacist intervention improved clinical outcomes for patients who are at high risk for a recurrent stroke/TIA event.

Aspirin and clopidogrel are the foremost secondary stroke prevention treatments. However, some patients do not demonstrate optimal response to these therapies due to drug-drug interactions, non-compliance, or resistance.

Patients treated with antiplatelets and at risk for recurrent stroke/TIA either underwent WBA, pharmacist intervention, and care from a neurology provider or received care from a neurology provider, alone. Antiplatelet therapy adjustments were recommended based on WBA ohms of resistance results to collagen and arachidonate or adenosine diphosphate.

268 patients (134 per group) were matched based on disease severity (ABCD² score mean=3.70±1.39), age (mean=68±13), and gender (WBA Females=60%, non-WBA Females=59%) with no significant difference in these variables or the number of visits in a 90-day period. WBA patients were more likely to be counseled on medication changes (135 vs. 33) and drug-drug interactions (30 vs. 7, Chi-square, p<0.001) than the neurologist only group. WBA at the initial visit revealed 61% of patients as non-responsive to their antiplatelet resulting in a recommended dose increase in 54 patients. Thirty percent were unable to undergo testing during the first visit commonly due to NSAID interactions. Based on ABCD² risk scores, 10 patients in each group were predicted to have a new event. However, WBA patients experienced one new stroke and three new TIAs while the neurologist only patients experienced two new strokes and two new TIAs.