Hart R G, Sherman D G, Easton J D, Cairns J A
University of Texas Health Science Center, San Antonio 78284-7883, USA.
Neurology. 1998 Sep;51(3):674-81. doi: 10.1212/wnl.51.3.674.
To review the risk and pathogenesis of stroke associated with nonvalvular atrial fibrillation (AF) and the efficacies and risks of stroke prevention strategies.
About 16% of ischemic strokes are associated with AF; AF is an independent risk factor for stroke.
Review of the literature, focusing on 13 randomized trials of antithrombotic therapy.
The overall risk of stroke in AF patients averages about 5%/y, but with wide variation depending on the presence of coexistent thromboembolic risk factors. AF patients with low (about 1% per year), moderate (about 3% per year), and high (about 6% per year) stroke risks have been identified, but the generalizability of risk stratification schemes to clinical practice has not been fully assessed. AF patients with prior stroke or transient ischemic attack, even if remote, are at highest risk (about 12% per year). Adjusted-dose warfarin (target International Normalized Ratio [INR] 2-3) is highly efficacious for preventing stroke in AF patients (about 70% risk reduction) and is safe for selected patients, if carefully monitored. Aspirin has a modest effect on reducing stroke (about 20% risk reduction). The numbers of AF patients that would need to be treated with warfarin instead of aspirin for 1 year to prevent one ischemic stroke are about 200, 70, and 20 for those with low, moderate and high risk, respectively.
Many patients with nonvalvular AF have substantial rates of ischemic stroke. Stratification of stroke risk identifies AF patients who benefit most and least from lifelong anticoagulation. Warfarin is recommended for high-risk AF patients who can safely receive it. Aspirin may be indicated for those with a low stroke risk and for those who cannot receive warfarin. For AF patients considered to have a moderate risk of stroke, individual bleeding risk during anticoagulation and patient preference should particularly influence the choice of antithrombotic prophylaxis.
综述与非瓣膜性心房颤动（AF）相关的卒中风险及发病机制，以及卒中预防策略的疗效和风险。
约16%的缺血性卒中与AF相关；AF是卒中的独立危险因素。
回顾文献，重点关注13项抗栓治疗的随机试验。
AF患者的总体卒中风险平均约为每年5%，但因并存血栓栓塞危险因素的情况不同而有很大差异。已确定卒中风险低（约每年1%）、中（约每年3%）和高（约每年6%）的AF患者，但风险分层方案在临床实践中的可推广性尚未得到充分评估。既往有卒中或短暂性脑缺血发作的AF患者，即使是既往发作，风险最高（约每年12%）。调整剂量的华法林（目标国际标准化比值[INR]为2 - 3）对预防AF患者的卒中非常有效（风险降低约70%），如果仔细监测，对特定患者是安全的。阿司匹林对降低卒中风险有一定作用（风险降低约20%）。对于低、中、高风险的AF患者，分别需要用华法林而非阿司匹林治疗1年以预防1次缺血性卒中的人数约为200、70和20。
许多非瓣膜性AF患者有较高的缺血性卒中发生率。卒中风险分层可识别出从终身抗凝中获益最大和最小的AF患者。推荐能安全接受华法林治疗的高风险AF患者使用华法林。对于卒中风险低的患者以及不能接受华法林治疗的患者，可考虑使用阿司匹林。对于被认为有中度卒中风险的AF患者，抗凝期间的个体出血风险和患者偏好应特别影响抗栓预防措施的选择。
