A Clinical Study In The Very Old Patients Treated With Different Antiplatelet Agents

Background Aspirin has been used widely in primary and secondary prevention and treatment in cardialvascular diseases. The current cardiology guidelines recommend that the dosage of aspirin should be used as low as possible on condition that it is effective. But the optimal dose of aspirin needed to maximize efficacy and minimize toxicity is still being debated, especially in the very old people aged 75 or over. There is a dearth of information about the effects and optimal dose of aspirin in this group individuals, and it is necessary to make further studies in this field.Several antiplatelet agents, such as aspirin, bokey (enteric-release aspirin), bamyl(buffered aspirin), clopidogrel et al, are available in current antithrombotic therapy. But which of them is most effective in the prevention of cardiovascular disease is still uncertain.The risk of gastrointestinal bleeding generally increases with the use of aspirin. Whether there is a dose-response relationship between aspirin prescription and upper gastrointestinal complications, and whether the other forms of antiplatelet agents, such as the varieties of aspirin and clopidogrel, would cause the same risk remains to be detected.Objective To detect the antiplatelet effects , the risk of gastrointestinalbleeding, the side-effects on neutrophils and platelets in using different doses and different forms of antiplatelet agents. And to find both an optimalantiplatelet agent and the optimal dose for the very old cardiovascular patients.Methods 182 old patients aged more than 75 with cardiovascular disease took part in the study. Those with blood diseases, hepatic disfunction, active gastrointestinal ulcer, a history of recent surgery, allergy to aspirin or clopidogrel, and a history of injury or bleeding in recent two weeks were excluded. Patients were radomized to receive aspirin 50mg, aspirin 100mg, bokey 100mg, bokey 200mg, clopidogrel 50mg daily, and the placebo group (fufang danshen diwan) . The placebo group admistrated 250mg, tid. The treatment was continued for 8 weeks. Before and after the study, blood specimens were collected in all eligible patients to test the blood routine values, prothrombin time (PT), prothrombin activity (PA), activated partial thromboplastin time (APTT) and platelet aggregation rate (PAG), and endoscopy was performed as well.Results There was no significant difference in age among the groups.Aspirin, bokey, and dopidogrel in this study can all inhibit platelet aggregation significantly compared with placebo(P<0.05), dopidogrel was more effective than aspirin and bokey 100mg/d. Although there was no significant difference in statistical analysis, there was still a tendency that aspirin 100mg/d was superior to 50mg/d, and bokey 200mg/d superior to 100mg/d in inhibiting platelet aggregation. Bokey 200mg/d was significantly superior to aspirin 50mg/d in antiplatelet effect, but there was no difference between dopidogrel 50mg/d and bokey 200mg/d. There was no significiant difference in the occurrence of gastric bleeding among all groups. The decreasing of neutrophil or platelet did not present in all eligible patients. Aspirin and bokey had no effect on coagulation system, while APTT was prolonged significantly in dopidogrel group as compared with placebo group.Conclusions â‘ Aspirin of different varieties more than 50mg/d and...