[Atrial fibrillation: anticoagulation or antiaggregation. Is there still a controversy?].
Unlike what happened regarding rheumatic atrial fibrillation, there was no consensus until few years ago about the indication for antithrombotic therapy in nonrheumatic atrial fibrillation. Nevertheless, as it was noticed a high prevalence of stroke in this last situation, several clinical trials were accomplished to clarify the role of those drugs. It was reviewed the five initial big trials, which in spite of having different dimensions, endpoints and design, were remarkably consistent in their results, showing in those patients taking varfarine a 60% reduction in ischemic stroke and systemic embolism. Those results were obtained with an acceptable risk of hemorrhage, which was related to anticoagulation intensity. An European trial showed similar results in secondary prevention, in patients with higher risk, all of them with a previous minor stroke. In some of those trials antiplatelet therapy was also evaluated but only one (SPAF I), showed a significant reduction of stroke with aspirin; the reductions of risk was meanwhile much smaller than with varfarine. As there were a high number of patients with indication for anticoagulants one tried to find thromboembolic risk factors, to identify the population potentially more prone to benefit from that therapy. It was possible in SPAF I trial to find some clinical and echocardiographic risk factors. SPAF II trial directly compare aspirine with varfarine, showing the superiority of the last one but also its greater haemorrhagic risk. That study permitted a better understanding of the indications of those two therapies, according to embolic and haemorrhagic risk of each patient.
Bonhorst
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Serviço de Cardiologia, Hospital de Santa Cruz, Linda-a-Velha.
D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D002561:Cerebrovascular Disorders / Q000209:etiology; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006801:Humans; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D012307:Risk Factors; D013923:Thromboembolism / Q000209:etiology / Q000517:prevention & control
D005343:Fibrinolytic Agents; D010975:Platelet Aggregation Inhibitors