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Vol. 30. Issue 12.
Pages 905-924 (December 2011)
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Vol. 30. Issue 12.
Pages 905-924 (December 2011)
Review article
Open Access
Antithrombotic therapy in nonvalvular atrial fibrillation: A narrative review
Terapêutica anti-trombótica na fibrilação auricular não-valvular: uma revisão narrativa
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Susana P.D. Sáa, Rui P. Rodriguesb, João Santos-Antunesc, Francisco Rocha Gonçalvesa, José Pedro L. Nunesa,
Corresponding author
jplnunes@med.up.pt

Corresponding author.
a Faculdade de Medicina, Universidade do Porto, Porto, Portugal
b Serviço de Medicina Interna, Hospital São João, Porto, Portugal
c Serviço de Gastroenterologia, Hospital São João, Porto, Portugal
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Abstract

Atrial fibrillation (AF) is an important and potentially modifiable cause of stroke. It has been known since 1989 that oral anticoagulant drugs, such as warfarin, lead to a dramatic decrease in stroke associated with AF. The best risk-benefit ratio is obtained with intensity of oral anticoagulant treatment for an INR of 2-3, even in the elderly. Given the risks of anticoagulant therapy, including bleeding, individual thromboembolic risk must be assessed in patients with AF. In 2009, dabigatran was shown to be a reasonable alternative to vitamin K antagonists, establishing itself as a major alternative to warfarin in AF patients. Rivaroxaban and apixaban have subsequently also been shown to be alternatives to warfarin. When there are contraindications to vitamin K antagonists, antiplatelet agents can produce a therapeutic effect, although much less than oral anticoagulants. Apixaban may be a better alternative to aspirin in this setting. Patients with low-risk atrial fibrillation (no risk factors) have not been the subjects of specific clinical trials. It is unclear what would be the best therapeutic choice for these patients.

Keywords:
Atrial fibrillation
Warfarin
Aspirin
Dabigatran
Rivaroxaban
Apixaban
Resumo

A fibrilacao auricular (FA) e uma causa importante e potencialmente modificavel do acidente vascular cerebral. Desde 1989 que se encontra demonstrado que o uso de anti-coagulantes orais, como a varfarina, se associa a uma reducao dramatica da incidencia de acidente vascular cerebral associado a FA. A intensidade da anticoagulacao oral com uma melhor relacao risco-beneficio e obtida com urn INR de 2-3, mesmo no paciente idoso. Tendo em consideracao os riscos da anticoagulacao oral, incluindo as hemorragias, e necessario estimar o risco tromboembolico individual nos doentes com FA. Em 2009, o dabigatrano mostrou ser uma alternativa razoavel aos antagonistas da vitamina K - vindo a estabelecer-se como uma alternativa importante a varfarina em doentes com FA. Foi subsequentemente demonstrado que quer o rivaroxabano quer o apixabano tern urn estatuto semelhante ao dabigatrano, enquanto alternativas importantes a varfarina. Quando existam contra-indicacoes a terapeutica com antagonistas da vitamina K, os antiplaquetarios podem produzir urn efeito terapeutico, sem duvida urn efeito muito menos importante do que os anticoagulantes orais. 0 apixabano podera ser uma alternativa preferivel a aspirina neste contexto. Os doentes com FA de “baixo risco” (sem factores de risco) nao foram estudados em ensaios clinicos levados a cabo especificamente para esta situacao. E pouco claro qual e a melhor alternativa terapeutica nestes doentes.

Palavras-chave:
Fibrilacao auricular
Varfarina
Aspirina
Dabigatrano
Rivaroxabano
Apixabano
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