JAMA. 1998;279(16):1273-7.
Nonvalvular atrial fibrillation (AF) carries an increased risk for stroke, but absolute rates of stroke vary widely within the broad spectrum of AF patients.
To prospectively validate a risk stratification scheme identifying patients with AF with low rates of stroke when given aspirin.
Prospective cohort study with mean duration of follow-up of 2.0 years, conducted between 1993 and 1997.
Outpatient clinics affiliated with academic medical centers.
Patients with AF categorized as "low risk" based on the absence of 4 prespecified thromboembolic risk factors: recent congestive heart failure or left ventricular fractional shortening of 25% or less, previous thromboembolism, systolic blood pressure greater than 160 mm Hg, or female sex at age older than 75 years.
All participants given aspirin, 325 mg/d.
Ischemic stroke (considered disabling when Rankin score was II or worse 1-3 months later) and systemic embolism (primary events).
Among 892 participants, the mean (SD) age was 67 (10) years, 78% were men, and histories of hypertension, diabetes, and ischemic heart disease were present in 46%, 13%, and 16%, respectively. The rate of primary events was 2.2% per year (95% confidence interval [CI], 1.6%-3.0%), of ischemic stroke was 2.0% per year (95% CI, 1.5%-2.8%), and of disabling ischemic strokes was 0.8% per year (95% CI, 0.5%-1.3%). Those with a history of hypertension had a higher rate of primary events (3.6% per year) than those with no history of hypertension (1.1% per year) (P<.001). The rate of disabling ischemic stroke was low in those with and without a history of hypertension (1.4% per year and 0.5% per year, respectively). The rate of major bleeding during aspirin therapy was 0.5% per year.
Patients with AF who have relatively low rates of ischemic stroke, particularly disabling stroke, during treatment with aspirin can be reliably identified.
非瓣膜性心房颤动（房颤）患者发生卒中的风险增加，但在广大房颤患者群体中，卒中的绝对发生率差异很大。
前瞻性验证一种风险分层方案，以识别服用阿司匹林时卒中发生率较低的房颤患者。
前瞻性队列研究，随访平均时长为2.0年，于1993年至1997年开展。
附属于学术医疗中心的门诊诊所。
根据不存在4种预先设定的血栓栓塞风险因素而被归类为“低风险”的房颤患者，这4种因素为：近期充血性心力衰竭或左心室射血分数缩短至25%或更低、既往血栓栓塞、收缩压大于160 mmHg或75岁以上女性。
所有参与者服用阿司匹林，325 mg/天。
缺血性卒中（当Rankin评分在1 - 3个月后为II级或更差时被视为致残性）和全身性栓塞（主要事件）。
在892名参与者中，平均（标准差）年龄为67（10）岁，78%为男性，高血压、糖尿病和缺血性心脏病史的患者分别占46%、13%和16%。主要事件发生率为每年2.2%（95%置信区间[CI]，1.6% - 3.0%），缺血性卒中发生率为每年2.0%（95% CI，1.5% - 2.8%），致残性缺血性卒中发生率为每年0.8%（95% CI，0.5% - 1.3%）。有高血压病史的患者主要事件发生率（每年3.6%）高于无高血压病史的患者（每年1.1%）（P <.001）。有和无高血压病史的患者致残性缺血性卒中发生率均较低（分别为每年1.4%和每年0.5%）。阿司匹林治疗期间大出血发生率为每年0.5%。
可以可靠地识别出在服用阿司匹林治疗期间缺血性卒中发生率相对较低，尤其是致残性卒中发生率较低的房颤患者。
