Effectiveness of platelet function analysis-guided aspirin and/or clopidogrel therapy in preventing secondary stroke: A systematic review and meta-analysis

Background: Antiplatelet medications such as aspirin and clopidogrel are usedfollowing thrombotic stroke or transient ischemic attack (TIA) to prevent a recurrent stroke.However, the antiplatelet treatments fail frequently, and patients experience recurrent stroke.One approach to lower the rates of recurrence may be the individualized antiplatelet therapies(antiplatelet therapy modification (ATM)) based on the results of platelet function analysis (PFA).This review was undertaken to gather and analyze the evidence about the effectiveness of suchapproaches. Methods: We searched Medline, CINAHL, Embase, Web of Science, and Cochranedatabases up to 7 January 2020. Results: Two observational studies involving 1136 patients wereincluded. The overall effects of PFA-based ATM on recurrent strokes (odds ratio (OR) 1.05;95% confidence interval (CI) 0.69 to 1.58), any bleeding risk (OR 1.39; 95% CI 0.92 to 2.10) ordeath hazard from any cause (OR 1.19; 95% CI 0.62 to 2.29) were not significantly different from thestandard antiplatelet therapy without ATM. Conclusions: The two studies showed opposite effectsof PFA-guided ATM on the recurrent strokes in aspirin non-responders, leading to an insignificantdifference in the subgroup meta-analysis (OR 1.59; 95% CI 0.07 to 33.77), while the rates of anybleeding events (OR 1.04; 95% CI 0.49 to 2.17) or death from any cause (OR 1.17; 95% CI 0.41 to 3.35)were not significantly different between aspirin non-responders with ATM and those without ATM.There is a need for large, randomized controlled trials which account for potential confounders suchas ischemic stroke subtypes, technical variations in the testing protocols, patient adherence to therapyand pharmacogenetic differences