Pearce L A, Hart R G, Halperin J L
Axio Research Corporation, Seattle, Washington, USA.
Am J Med. 2000 Jul;109(1):45-51. doi: 10.1016/s0002-9343(00)00440-x.
The risk of ischemic stroke varies widely among patients with nonvalvular atrial fibrillation, influencing the choice of prophylactic antithrombotic therapy. We assessed three schemes for stroke risk stratification in these patients who were treated with aspirin and who did not have prior cerebral ischemia.
Criteria from three schemes of risk stratification were applied to a longitudinally observed cohort of patients with atrial fibrillation who did not have prior cerebral ischemia and who were treated with aspirin alone or aspirin combined with low, ineffective doses of warfarin in a multicenter clinical trial. The ability of the schemes to identify patients at high (>/=6%), low (</=2%), and intermediate annual risks of ischemic stroke was assessed.
During a mean follow-up of 1.8 years, 48 ischemic strokes occurred among 1,073 patients with atrial fibrillation who were taking aspirin (rate = 2.5 per 100 person-years). Each of the three schemes predicted stroke and disabling stroke, and successfully identified patients at low risk (observed stroke rates of 0.3 to 1.1 per 100 person-years), although the fractions of the cohort that were categorized as low risk varied from 14% to 45%. The observed rates of ischemic stroke among patients categorized as high risk ranged from 3.5 to 7.2 per 100 person-years among the stratification schemes. Two schemes considered all patients >75 years old as high risk (observed stroke rate 4.2 per 100 person-years), while the remaining scheme classified one third of patients in this age group as low risk (observed stroke rate 0.6 per 100 person-years).
When tested in a large cohort of patients with atrial fibrillation who were treated with aspirin, available risk-stratification schemes successfully identified patients with low rates of ischemic stroke, but less consistently identified high-risk patients.
非瓣膜性心房颤动患者发生缺血性卒中的风险差异很大，这会影响预防性抗血栓治疗的选择。我们评估了三种针对这些接受阿司匹林治疗且无既往脑缺血史患者的卒中风险分层方案。
在一项多中心临床试验中，将三种风险分层方案的标准应用于一组纵向观察的心房颤动患者队列，这些患者无既往脑缺血史，单独接受阿司匹林治疗或接受阿司匹林联合低剂量、无效剂量华法林治疗。评估这些方案识别缺血性卒中年度高风险（≥6%）、低风险（≤2%）和中度风险患者的能力。
在平均1.8年的随访期间，1073例服用阿司匹林的心房颤动患者中发生了48例缺血性卒中（发生率为每100人年2.5例）。三种方案均能预测卒中及致残性卒中，并成功识别出低风险患者（观察到的卒中发生率为每100人年0.3至1.1例），尽管被归类为低风险的队列比例在14%至45%之间。在分层方案中，被归类为高风险的患者中观察到的缺血性卒中发生率为每100人年3.5至7.2例。两种方案将所有75岁以上患者视为高风险（观察到的卒中发生率为每100人年4.2例），而其余方案将该年龄组三分之一的患者归类为低风险（观察到的卒中发生率为每100人年0.6例）。
在一大组接受阿司匹林治疗的心房颤动患者中进行测试时，现有的风险分层方案成功识别出缺血性卒中发生率低的患者，但在识别高风险患者方面不太一致。
