Neurology Unit, Rabin Medical Center, Golda Campus, Petach Tikva and Tel Aviv University, Tel Aviv, Israel.
Department of Vascular Surgery, UMC Utrecht, Utrecht, the Netherlands.
Int J Stroke. 2016 Dec;11(9):1020-1027. doi: 10.1177/1747493016660319. Epub 2016 Jul 19.
Silent brain infarcts are common in patients at increased risk of stroke and are associated with a poor prognosis. In patients with asymptomatic carotid stenosis, similar adverse associations were claimed, but the impact of previous infarction or symptoms on the beneficial effects of carotid endarterectomy is not clear. Our aim was to evaluate the impact of prior cerebral infarction in patients enrolled in the Asymptomatic Carotid Surgery Trial, a large trial with 10-year follow-up in which participants whose carotid stenosis had not caused symptoms for at least six months were randomly allocated either immediate or deferred carotid endarterectomy.
The first Asymptomatic Carotid Surgery Trial included 3120 patients. Of these, 2333 patients with baseline brain imaging were identified and divided into two groups irrespective of treatment assignment, 1331 with evidence of previous cerebral infarction, defined as a history of ischemic stroke or transient ischemic attack > 6 months prior to randomization or radiological evidence of an asymptomatic infarct (group 1) and 1002 with normal imaging and no prior stroke or transient ischemic attack (group 2). Stroke and vascular deaths were compared during follow-up, and the impact of carotid endarterectomy was observed in both groups.
Baseline characteristics of patients with and without baseline brain imaging were broadly similar. Of those included in the present report, male gender and hypertension were more common in group 1, while mean ipsilateral stenosis was slightly greater in group 2. At 10 years follow-up, stroke was more common among participants with cerebral infarction before randomization (absolute risk increase 5.8% (1.8-9.8), p = 0.004), and the risk of stroke and vascular death was also higher in this group (absolute risk increase 6.9% (1.9-12.0), p = 0.007). On multivariate analysis, prior cerebral infarction was associated with a greater risk of stroke (hazard ratio = 1.51, 95% confidence interval: 1.17-1.95, p = 0.002) and of stroke or other vascular death (hazard ratio = 1.30, 95% confidence interval: 1.11-1.52, p = 0.001). At 10 years, greater absolute benefits from immediate carotid endarterectomy were seen in those patients with prior cerebral infarction (6.7% strokes immediate carotid endarterectomy vs. 14.7% delayed carotid endarterectomy; hazard ratio 0.47 (0.34-0.65), p = 0.003), compared to those lower risk patients without prior cerebral infarction (6.0% vs. 9.9%, respectively; hazard ratio 0.61 (0.39-0.94), p = 0.005), though it must be emphasized that the first Asymptomatic Carotid Surgery Trial was not designed to test this retrospective and non-randomized comparison.
Asymptomatic carotid stenosis patients with prior cerebral infarction have a higher stroke risk during long-term follow-up than those without prior cerebral infarction. Evidence of prior ischemic events might help identify patients in whom carotid intervention is particularly beneficial.
无症状性脑梗死在高卒中风险患者中很常见，与预后不良有关。在无症状性颈动脉狭窄患者中，也有类似的不利关联，但以前的梗死或症状对颈动脉内膜切除术的有益效果的影响尚不清楚。我们的目的是评估既往脑梗死对无症状性颈动脉内膜切除术试验（Asymptomatic Carotid Surgery Trial）参与者的影响，这是一项具有 10 年随访的大型试验，其中至少 6 个月没有因颈动脉狭窄引起症状的参与者被随机分配接受立即或延迟颈动脉内膜切除术。
第一阶段无症状性颈动脉内膜切除术试验纳入了 3120 名患者。其中，有 2333 名患者有基线脑部影像学资料，将其分为两组，不论治疗分配如何，1331 名患者有既往脑梗死的证据，定义为随机分组前 6 个月以上有缺血性卒中和短暂性脑缺血发作史或影像学证据显示无症状性梗死（第 1 组），1002 名患者影像学正常且无既往卒中和短暂性脑缺血发作（第 2 组）。在随访期间比较卒中和血管性死亡，观察颈动脉内膜切除术在两组中的效果。
有和没有基线脑部影像学资料的患者的基线特征大致相似。在本报告中纳入的患者中，第 1 组男性和高血压更为常见，而第 2 组同侧狭窄程度稍大。在 10 年随访时，随机分组前有脑梗死的患者卒中更为常见（绝对风险增加 5.8%（1.8-9.8），p=0.004），并且该组的卒中风险和血管性死亡风险也更高（绝对风险增加 6.9%（1.9-12.0），p=0.007）。多变量分析显示，既往脑梗死与卒中风险增加相关（风险比=1.51，95%置信区间：1.17-1.95，p=0.002），以及卒中或其他血管性死亡风险增加（风险比=1.30，95%置信区间：1.11-1.52，p=0.001）。在 10 年时，与延迟颈动脉内膜切除术相比，有既往脑梗死的患者立即颈动脉内膜切除术有更大的绝对获益（6.7%的卒中和立即颈动脉内膜切除术与 14.7%的延迟颈动脉内膜切除术；风险比 0.47（0.34-0.65），p=0.003），而那些风险较低的无既往脑梗死患者获益较小（6.0%与 9.9%；风险比 0.61（0.39-0.94），p=0.005），但必须强调的是，第一阶段无症状性颈动脉内膜切除术试验并非设计用于检验这种回顾性和非随机比较。
在长期随访中，有既往脑梗死的无症状性颈动脉狭窄患者的卒中风险高于无既往脑梗死的患者。既往缺血事件的证据可能有助于识别颈动脉介入治疗特别有益的患者。
