大部分的脑中卒都源自脑部血管栓塞。对于某些血液中有微栓子或是小的血凝块的人而言，他们脑中卒发生几率将升高很多。
来自香港中文大学的Lawrence Ka Sing Wong与研究团队的人员合作进行的随机临床试验发现，调查分析抗血凝药作为中卒二次预防的临床效果。研究结果显示，联合用药，阿司匹林配合clopidogrel使用预防脑内微小栓塞的效果比单独使用阿司匹林的效果更加。
研究小组选用100名近期有中卒病史的患者进行追踪调查，其中47名患者接受双重用药试验，另外的53名患者接受单一用药试验，这是个为期7天的临床试验。在试验过程中，第二天和第七天，所有患者接受颅部多普勒扫描，观察脑部的微小栓塞信号。
在第二天，12名接受双重用药的病人和27名接受单一用药的病人经多普勒扫描发现有微小栓塞信号。在药物副作用方面，两组病人所表现的结果是相似的，只有2个接受双重用药的患者有轻微的出血现象。
这些研究结果表明，双重用药是一种更为有效减轻栓塞，预防二次中风的有效办法。研究小组下一步的研究计划是，分析计算双重用药方式降低中风几率的具体百分数。
推荐原文出处：
The Lancet Neurology doi:10.1016/S1474-4422(10)70060-0
Clopidogrel plus aspirin versus aspirin alone for reducing embolisation in patients with acute symptomatic cerebral or carotid artery stenosis (CLAIR study): a randomised, open-label, blinded-endpoint trial
Ka Sing Lawrence Wong FRCP a , Christopher Chen FRCP b, Jianhui Fu MD c, Hui Meng Chang FRCP d, Nijasri C Suwanwela MD e, Yining N Huang MD f, Zhao Han MD g, Kay Sin Tan FRCP h, Disya Ratanakorn MD i, Pavithra Chollate MD j, Yudong Zhao PhD j, Angeline Koh BHSc j, Qing Hao MD a, Hugh S Markus FRCP k, for the CLAIR study investigators
Background
Few randomised clinical trials have investigated the use of antithrombotic drugs for early secondary prevention of stroke or transient ischaemic attack in patients with intracranial atherosclerotic stenosis. Microembolic signals, detected by transcranial doppler, are a surrogate marker of future stroke risk and have been used to show treatment efficacy in patients with extracranial carotid stenosis. We aimed to investigate whether treatment with clopidogrel plus aspirin reduced the number of microembolic signals detected with transcranial doppler ultrasound compared with aspirin alone in patients with recent stroke.
Methods
The clopidogrel plus aspirin for infarction reduction in acute stroke or transient ischaemic attack patients with large artery stenosis and microembolic signals (CLAIR) trial was a randomised, open-label, blinded-endpoint trial. Between Oct 28, 2003, and Nov 19, 2008, patients with acute ischaemic stroke or transient ischaemic attack who had symptomatic large artery stenosis in the cerebral or carotid arteries and in whom microembolic signals were present on transcranial doppler were randomly assigned within 7 days of symptom onset to receive clopidogrel (300 mg for the first day, then 75 mg daily) plus aspirin (75―160 mg daily) or aspirin alone (75―160 mg daily) for 7 days. Patients were randomly assigned in blocks of four or six by use of a randomisation website. Monitoring of microembolic signals on transcranial doppler was done on days 2 and 7. The primary endpoint was the proportion of patients who had microembolic signals on day 2. Analysis was by modified intention to treat. All analyses were done by an investigator masked to both patient identity and the day the recording was taken. This trial is registered with the Centre for Clinical Trials, Chinese University of Hong Kong, number CUHK_CCT00164.
Findings
100 patients were randomly assigned to clopidogrel plus aspirin (n=47) or aspirin monotherapy (n=53). 93 of 100 patients had symptomatic intracranial stenosis in either the intracranial internal carotid artery or the middle cerebral artery: 45 of 46 in the dual therapy group and 48 of 52 in the monotherapy group. At day 2, 14 of 45 patients in the dual therapy group and 27 of 50 patients in the monotherapy group for whom data were available had at least one microembolic signal on transcranial doppler (relative risk reduction 424%, 95% CI 46―652; p=0025). Adverse events were similar in the two groups. No patients had intracranial or severe systemic haemorrhage, but two patients in the dual therapy group had minor haemorrhages.
Interpretation
Combination therapy with clopidogrel and aspirin is more effective than aspirin alone in reducing microembolic signals in patients with predominantly intracranial symptomatic stenosis. Clinical trials are now warranted to investigate whether this combination treatment also results in a reduction in stroke incidence.
