Recent Advances in Antithrombotic Therapy for Stroke Prevention(Special Issue in Hornor of the Retirement of Professor Makoto Iwata at the Department of Neurology, Tokyo Women\u27s Medical University)

Antiplatelet therapy is indicated in patients with non-cardioembolic stroke, while anticoagulant therapy is indicated in those with cardioembolic stroke. Aspirin is the first line of antiplatelet agent, although the efficacy is modest, which is argued with termed aspirin resistance. Thienopyridines such as ticlopidine and clopidogrel are marginally more efficacious than aspirin, among which clopidogrel has less serious side effects than ticlopidine. Phosphodiesterase inhibitors such as dipyridamole and cilostazol have less bleeding risk than aspirin or thinopyridines. Dual antiplatelet therapy may be a more potent antiplatelet strategy, although it may increase the risk of hemorrhage. Combination of aspirin and clopidogrel is not recommended for long-term prevention because this combination does not have clear additional benefit with increased bleeding risk. Combination of aspirin with dipyridamole or cilostazol appears to more reduce the risk of stroke without increasing hemorrhagic complications than aspirin alone. Warfarin is indicated for stroke prevention in high risk patients with non-valvular atrial fibrillation (NVAF). However, warfarin is underused because of inconvenience including blood coagulation monitoring, limitation of vitamin K intake, and drug interactions. Recently, many oral direct thrombin and factor Xa inhibitors have been developed, and clinical trials are ongoing to compare with warfarin in high risk patients with NVAF.神経内科学教室岩田誠教授退任記念特別