Association between platelet function and recurrent ischemic vascular events after TIA and minor stroke


Platelet activation and aggregation play an important role in the pathological and physiological processes of recurrent ischemic vascular events in stroke patients. The purpose of this study is to determine the association between platelet function measured in the acute period and recurrent ischemic vascular events in patients with transient ischemic attack (TIA) or minor stroke. A total of 417 patients who were within the 24-hour period of clopidogrel-aspirin therapy after onset of a minor stroke or high-risk transient ischemic attack according to the Clopidogrel in High-risk patients with Acute Nondisabling Cerebrovascular Events (CHANCE) trial were included in this study. The platelet aggregation ratio was detected using a method of continuous platelet counting; patients underwent CYP2C19 genotyping, and the baseline data were recorded. The patients underwent a 6-month follow-up period during which the recurrent ischemic vascular events were observed. Logistic regression analysis was performed to obtain the risk factors for recurrent ischemic vascular events. The number of patients with recurrent ischemic events who had an arachidonic acid-induced maximum platelet aggregation ratio (MAR-AA) (aspirin 100 mg) (31.85 ± 12.86 vs. 26.71 ± 12.44, p = 0.007) and adenosine diphosphate-induced maximum platelet aggregation ratio (MAR-ADP) after the administration of 75 mg clopidogrel for 12 ± 2 days (65.82 ± 10.72 vs. 53.10 ± 12.98, p < 0.001) was significantly higher compared with the no ischemic vascular event group. Multivariate logistic regression analyses showed that being a carrier of the CYP2C19 loss-of-function (LOF) allele (OR = 2.308, 95% CI: 1.087 ~ 4.901, p = 0.029) as well as the MAR-AA (aspirin 100 mg) (OR = 1.028, 95% CI: 1.006  ~  1.052, p = 0.014) and MAR-ADP after the administration of 75 mg clopidogrel (OR = 1.067, 95% CI: 1.037 ~ 1.095, p < 0.001) were risk factors for ischemic vascular events. The MAR-ADP after the administration of 75 mg clopidogrel was significantly higher in patients who were carriers of the CYP2C19 (LOF) allele compared with non-carriers (57.53 ± 13.32 vs. 50.86 ± 12.55, p < 0.001), and no significant differences between the CYP2C19 LOF allele carriers and non-carriers in the MAR-ADP were detected after the administration of 300 mg clopidogrel (37.18 ± 11.36 vs. 35.86 ± 12.49, p = 0.264). Being a carrier of the CYP2C19 LOF allele has a significant influence on clopidogrel response. Platelet function is closely related to recurrent ischemic vascular events in acute minor stroke or TIA patients.
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