Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Cerebrovasc Dis. 2013;36(5-6):373-82. doi: 10.1159/000355571. Epub 2013 Nov 9.
Some ischemic strokes in patients with atrial fibrillation (AF) are caused by noncardioembolic etiologies (AF-unrelated stroke), but not AF itself (AF-related stroke). However, most clinical trials on the risk of stroke in AF have not distinguished between these. We investigated the frequency and features of AF-unrelated versus AF-related strokes in patients with AF plus ischemic stroke. We hypothesized that certain clinical factors, including chronicity of AF, treatment at the time of stroke onset and echocardiographic findings, may help to discriminate between AF-related and AF-unrelated strokes. The mechanisms and antithrombotic medications at the time of stroke recurrence in the two groups were also examined.
Consecutive patients with ischemic stroke within 7 days of symptom onset and with AF were included. Patients were classified according to the previously published criteria. Clinical factors including CHADS2 and CHA2DS2-VASc scores and transthoracic echocardiographic (TTE) findings were evaluated.
Of 522 patients, 424 (81.2%) were grouped as AF-related stroke and the remaining 90 (17.2%) were classified as AF-unrelated stroke. Among the patients with AF-unrelated stroke, 51 (9.8%) were categorized as possible large artery atherosclerosis and 38 (7.3%) as possible small artery occlusion; 1 patient (0.2%) was assigned to miscellaneous cause. The AF-related and AF-unrelated strokes had similar CHADS2 and CHA2DS2-VASc scores. However, compared to AF-unrelated stroke, AF-related stroke was independently associated with female sex (odds ratio, OR, 2.19; 95% confidence interval, CI, 1.18-4.05), sustained AF (OR, 2.09; 95% CI, 1.21-3.59), inadequate anticoagulation at stroke onset (OR, 3.21; 95% CI, 1.33-7.75) and left ventricular dysfunction on TTE (OR, 2.84; 95% CI, 1.40-5.74). We identified 26 patients who experienced 2 strokes during the study period. The initial stroke subtype was a strong predictor of the recurrent stroke mechanism (p < 0.001). Among 17 events of AF-related recurrent stroke in these subpopulation, only 2 strokes (11.8%) occurred in a setting of adequate anticoagulation, whereas 4 out of 9 patients (44.4%) who had AF-unrelated strokes at recurrence were sufficiently anticoagulated at the time of admission (p = 0.138).
AF is not always a culprit of stroke in patients with AF plus ischemic stroke; approximately one sixth of these cases are unrelated to AF and have distinct characteristics compared to AF-related stroke. There are significant differences in terms of some clinical and TTE parameters between AF-related and AF-unrelated stroke. Future studies are warranted to optimize strategies for risk stratification, treatment and prevention of stroke in these patients.
部分房颤（AF）患者的缺血性脑卒中由非心源性病因（AF 无关性脑卒中）引起，而非 AF 本身（AF 相关性脑卒中）。然而，大多数关于 AF 患者脑卒中风险的临床试验并未对此加以区分。我们研究了 AF 合并缺血性脑卒中患者中 AF 相关性与 AF 无关性脑卒中的发生频率和特征。我们假设某些临床因素，包括 AF 的慢性程度、脑卒中发作时的治疗以及超声心动图发现，可能有助于区分 AF 相关性与 AF 无关性脑卒中。我们还检查了两组患者脑卒中复发时的机制和抗血栓药物治疗。
纳入了症状发作后 7 天内发生缺血性脑卒中且合并 AF 的连续患者。根据先前发表的标准对患者进行分类。评估了包括 CHADS2 和 CHA2DS2-VASc 评分以及经胸超声心动图（TTE）发现在内的临床因素。
在 522 例患者中，424 例（81.2%）被归类为 AF 相关性脑卒中，其余 90 例（17.2%）被归类为 AF 无关性脑卒中。在 AF 无关性脑卒中患者中，51 例（9.8%）为可能大动脉粥样硬化，38 例（7.3%）为可能小动脉闭塞；1 例（0.2%）为其他原因。AF 相关性与 AF 无关性脑卒中的 CHADS2 和 CHA2DS2-VASc 评分相似。然而，与 AF 无关性脑卒中相比，AF 相关性脑卒中与女性（比值比[OR]，2.19；95%置信区间[CI]，1.18-4.05）、持续性 AF（OR，2.09；95% CI，1.21-3.59）、脑卒中发作时抗凝不足（OR，3.21；95% CI，1.33-7.75）和 TTE 左心室功能障碍（OR，2.84；95% CI，1.40-5.74）独立相关。在研究期间，我们发现 26 例患者发生了 2 次脑卒中。初始脑卒中亚型是预测复发性脑卒中机制的有力指标（p < 0.001）。在这些亚组中 17 例 AF 相关性复发性脑卒中事件中，仅有 2 例（11.8%）在充分抗凝的情况下发生，而在 9 例复发性 AF 无关性脑卒中患者中，有 4 例（44.4%）在入院时得到了充分抗凝（p = 0.138）。
AF 并非 AF 合并缺血性脑卒中患者脑卒中的始终原因；这些患者中约有六分之一与 AF 无关，且与 AF 相关性脑卒中具有不同的特征。AF 相关性与 AF 无关性脑卒中在某些临床和 TTE 参数方面存在显著差异。有必要开展进一步的研究，以优化这些患者的风险分层、治疗和脑卒中预防策略。
