[Antiplatelet therapy: update in secondary stroke prevention].

Antiplatelet therapy is indicated in patients with non-cardioembolic stroke. The clinically used antiplatelet agents for secondary stroke prevention in this group of patients include the cyclooxygenase-1 (COX-1) inhibitor aspirin, the ADP receptor (P2Y12) inhibitors clopidogrel and ticlopidine, and the phosphodiesterase (PDE) inhibitors cilostazol and dipyridamole. Per medical economic data, aspirin is the most widely used antiplatelet agent. However, its use affords modest reduction in the risk of stroke recurrence and increases the risk of hemorrhagic stroke. The CSPS2 showed that the incidence of stroke recurrence was lower in patients receiving cilostazol than in those receiving aspirin. Furthermore, it showed that the incidence of intra- or extracranial hemorrhage requiring hospitalization in cilostazol-treated patients was approximately half of that in aspirin-treated patients. The study also showed that the incidence of hemorrhagic stroke was significantly lower in patients receiving cilostazol than in those receiving aspirin. Meta-analysis of the CARESS and CLAIR studies showed a significant reduction of microembolic signals (MES) on transcranial Doppler (TCD) monitoring by dual antiplatelet therapy (DAPT) with aspirin and clopidogrel than treatment with aspirin alone in patients who experienced a transient ischemic attack (TIA) or stroke with extra- or intracranial artery stenosis and MES positivity. The CHANCE study conducted in China showed a lower incidence of ischemic stroke in DAPT-treated patients than in those treated with aspirin monotherapy, while the incidence of hemorrhagic stroke was similar between the 2 treatment groups. However, DAPT should be restricted in the acute phase of stroke or TIA in acute settings. Novel antiplatelet agents have been developed for stroke prevention, and large randomized clinical trials should be conducted to evaluate the efficacy and safety of these agents when used singularly or in combination.