The fate of asymptomatic severe carotid stenosis in the era of best medical therapy

<i>Background</i>: Medical therapy for asymptomatic carotid artery stenosis (ACAS) may obviate the carotid revascularization, according to recent literature reports, but many studies also considered moderate carotid artery stenosis (50–69% NASCET). This study reviews the most recent series of ACAS focusing on ipsilateral transient ischemic attack (TIA) stroke and annual risk of stroke in patients with ACAS ≥70%, thereby also evaluating the adherence to best medical therapy (BMT). <i>Methods</i>: A systematic review consisting of all the series of patients with ACAS being treated medically was performed, which was published after 2005. The annual pooled risk of ipsilateral TIA-stroke and stroke in patients with ACAS ≥70% was calculated. A subgroup of studies with BMT defined as ≥90% of the patients in antiplatelet and statin therapy was performed. <i>Results</i>: Eleven studies, with the enrolling period from 1996 to 2009, were reviewed. Overall, 2185 patients were considered, with a follow-up from 2 to 13 years, for a total of 6834 patients/year. The pooled risk was 3.4%/year for ipsilateral TIA-stroke and 1.6%/year for stroke. Five studies, published from 2014, had BMT adherence, for a total of 1665 patients/year. The pooled risk was 3.5%/year for ipsilateral TIA-stroke and for stroke. <i>Conclusion</i>: The most recent series of ACAS ≥70% and BMT had an overall stroke rate which is relatively low; however, the risk of developing symptoms is still relevant (3.4%/year).

### 研究背景
近期文献表明，无症状颈动脉狭窄（asymptomatic carotid artery stenosis, ACAS）患者接受药物治疗可免除颈动脉血管重建术，但诸多研究亦纳入了狭窄程度为50%~69%（北美症状性颈动脉内膜切除术试验，North American Symptomatic Carotid Endarterectomy Trial, NASCET）的中度颈动脉狭窄患者。本研究聚焦狭窄程度≥70%的无症状颈动脉狭窄患者，对其同侧短暂性脑缺血发作（transient ischemic attack, TIA）卒中事件及年度卒中风险相关的最新队列研究进行综述，同时评估患者对最佳药物治疗（best medical therapy, BMT）的依从性。
### 研究方法
本研究对2005年之后发表的、所有针对接受药物治疗的无症状颈动脉狭窄患者的队列研究开展系统综述，计算狭窄程度≥70%的无症状颈动脉狭窄患者的同侧TIA-卒中事件及卒中的年度合并风险，并针对其中将最佳药物治疗定义为≥90%患者接受抗血小板与他汀类药物治疗的亚组研究进行分析。
### 研究结果
本综述共纳入11项队列研究，患者入组时间跨度为1996年至2009年，共计纳入2185例患者，随访时长2至13年，总随访人年数达6834。狭窄程度≥70%的无症状颈动脉狭窄患者的同侧TIA-卒中事件年度合并风险为3.4%/年，卒中年度合并风险为1.6%/年。其中5项2014年及之后发表的研究报告了最佳药物治疗依从性情况，共涉及1665随访人年，其同侧TIA-卒中事件年度合并风险为3.5%/年，卒中年度合并风险为3.5%/年。
### 研究结论
针对狭窄程度≥70%且接受最佳药物治疗的无症状颈动脉狭窄患者的最新队列研究显示，其总体卒中发生率相对较低，但出现症状性事件的风险仍不容忽视（3.4%/年）。