Saraiva José Francisco Kerr
Cardiology Discipline, Pontifical Catholic University of Campinas School of Medicine, Campinas, Brazil.
Cardiol Ther. 2018 Jun;7(1):15-24. doi: 10.1007/s40119-018-0106-1. Epub 2018 Feb 27.
Atrial fibrillation (AF) is an established risk factor for a first or recurrent stroke. Despite proven efficacy in preventing stroke in patients with AF, warfarin is underused, partly due to safety concerns. Recent randomized trials have shown that non-vitamin K antagonist oral anticoagulants (NOACs) such as dabigatran (a direct thrombin inhibitor) and apixaban, edoxaban, and rivaroxaban (factor Xa inhibitors) are not only non-inferior or superior to warfarin but also demonstrate a decreased risk of cerebrovascular bleeding among patients with AF and moderate to high risk of stroke. Additionally, NOACs have an advantage of requiring no monitoring of the international normalized ratio compared with warfarin. This review summarizes the published literature on NOACs for the primary and secondary prevention of ischemic strokes, with an emphasis on the expected absolute benefits from the introduction of such agents. As compared with warfarin, NOACs significantly reduce the risk of hemorrhagic stroke, and only dabigatran (150 mg twice daily) was found to significantly reduce the risk of ischemic stroke. However, measures of relative benefits from medical interventions do not immediately provide the estimated benefit to be derived from an individual patient, something best done by considering the expected absolute benefit. The number needed to treat (NNT) is presented for various outcomes in the phase 3 trials of NOACs. Despite the important progress achieved with the introduction of NOACs, the availability of at least four agents with different efficacy and safety performances in comparison with warfarin prompts the question of whether any of these agents is preferable to another. It is hoped that future studies on the efficacy, safety, and economic performance of NOACs will further allow for rational choices within this important therapeutic class. Meanwhile, the NNT may be a valid metric to be considered by clinicians faced with the need to make such choices.
心房颤动（AF）是首次或复发性中风的既定危险因素。尽管华法林在预防房颤患者中风方面已被证明有效，但由于安全问题，其使用不足。最近的随机试验表明，非维生素K拮抗剂口服抗凝剂（NOACs），如达比加群（一种直接凝血酶抑制剂）和阿哌沙班、依度沙班及利伐沙班（Xa因子抑制剂），不仅不劣于或优于华法林，而且在房颤且中风风险为中度至高度的患者中，还显示出脑血管出血风险降低。此外，与华法林相比，NOACs具有无需监测国际标准化比值的优势。本综述总结了已发表的关于NOACs用于缺血性中风一级和二级预防的文献，重点关注引入此类药物的预期绝对获益。与华法林相比，NOACs显著降低了出血性中风的风险，且仅发现达比加群（每日两次，每次150mg）能显著降低缺血性中风的风险。然而，医疗干预相对获益的衡量标准并不能立即提供个体患者可获得的估计获益，最好通过考虑预期绝对获益来进行评估。文中给出了NOACs 3期试验中各种结局的治疗所需人数（NNT）。尽管引入NOACs取得了重要进展，但与华法林相比，至少有四种具有不同疗效和安全性表现的药物可供选择，这引发了一个问题，即这些药物中是否有任何一种比另一种更具优势。希望未来关于NOACs疗效、安全性和经济表现的研究能进一步有助于在这一重要治疗类别中做出合理选择。同时，NNT可能是临床医生在面临此类选择时可考虑的一个有效指标。
