Stroke. 1990 Apr;21(4):538-45. doi: 10.1161/01.str.21.4.538.
Individuals with nonvalvular atrial fibrillation are at increased risk of stroke. The Stroke Prevention in Atrial Fibrillation Study is a 15-center randomized clinical trial examining the risks and benefits of low-intensity warfarin (prothrombin time of 1.3-1.8 times control) and aspirin (325 mg/day) in patients with constant or intermittent atrial fibrillation. Candidates for anticoagulation (group I) are randomized to receive warfarin in an open-label fashion, aspirin, or placebo; the last two treatments are given in a double-blind fashion. Warfarin-ineligible patients (group II) are randomized to receive aspirin or placebo in a double-blind fashion. Primary end points are ischemic stroke and systemic embolism. Secondary end points are death, transient ischemic attack, myocardial infarction, and unstable angina pectoris. Analysis is based on the intention-to-treat principle. The anticipated rate of primary end points in patients receiving placebo is 6%/yr. The sample size of 1,644 patients is based on a projected reduction in the rate of primary end points of 50% by warfarin and of 33% by aspirin (beta = 0.2, alpha = 0.05). Patient entry commenced in June 1987 and will continue for 3 years, with an additional year of follow-up. High-risk subsamples identified by clinical and echocardiographic criteria are sought prospectively.
非瓣膜性心房颤动患者的卒中风险增加。心房颤动卒中预防研究是一项由15个中心开展的随机临床试验，旨在研究低强度华法林（凝血酶原时间为对照值的1.3 - 1.8倍）和阿司匹林（325毫克/天）对持续性或间歇性心房颤动患者的风险和益处。抗凝治疗候选者（I组）被随机分为接受开放标签的华法林、阿司匹林或安慰剂治疗；后两种治疗以双盲方式给予。不符合使用华法林条件的患者（II组）被随机分为接受双盲方式的阿司匹林或安慰剂治疗。主要终点为缺血性卒中和全身性栓塞。次要终点为死亡、短暂性脑缺血发作、心肌梗死和不稳定型心绞痛。分析基于意向性治疗原则。接受安慰剂治疗患者的主要终点预期发生率为每年6%。1644例患者的样本量基于预计华法林可使主要终点发生率降低50%、阿司匹林可使其降低33%（β = 0.2，α = 0.05）。患者入组于1987年6月开始，将持续3年，并另有1年的随访期。前瞻性地寻找通过临床和超声心动图标准确定的高危亚组。
