A population-based study in UK revealed that the clinical burden of cryptogenic transient ischaemic attacks (TIA) and stroke is substantial. Although stroke recurrence rates are comparable with other subtypes, cryptogenic events have the fewest atherosclerotic markers and no excess of cardioembolic markers. Among 2555 patients with a first TIA or ischaemic stroke, 812 (32%) had cryptogenic events (incidence of cryptogenic stroke 0·36 per 1000 population per year) from April 1, 2002, to March 31, 2014. The cryptogenic group had fewer atherosclerotic risk factors than the large artery disease, small vessel disease, and cardioembolic groups. Compared with patients with large artery events, those with cryptogenic events had less hypertension, diabetes, peripheral vascular disease, hypercholesterolaemia, and history of smoking, and compared with small vessel and cardioembolic subtypes, they had no excess risk of asymptomatic carotid disease or acute coronary events during follow-up. Compared with large artery and small vessel subtypes combined, patients with cryptogenic events also had no excess of minor-risk echocardiographic abnormalities or paroxysmal atrial fibrillation (AF) at baseline or of new AF or presumed cardioembolic events during follow-up. The findings suggest appropriate secondary prevention and throw into question the role of paroxysmal AF as the major cause of cryptogenic stroke. Source: http://www.thelancet.com/英国一项以人群为基础的研究显示，原因不明的短暂性脑缺血发作（TIA）和脑卒中的临床负担很重。虽然卒中复发率与其他亚型相似，原因不明者动脉粥样硬化的标志最少且无多余的心源性脑梗标志。从2002年4月1日至2014年3月31日，2555例首次短暂性脑缺血发作或缺血性中风者中，812例（32％）原因不明（原因不明卒中发生率为每年每1000人0·36）。原因不明组动脉粥样硬化的危险因素比大血管病变，小血管病变，和心源性脑梗组较少。与大血管病变者相比，那些原因不明者高血压，糖尿病，周围血管病，高胆固醇血症，吸烟史较少；与小血管和心源性亚型相比，随访期间他们也没有更高的无症状颈动脉狭窄或急性冠脉事件的风险。与大动脉和小血管亚型结合者相比，原因不明者起初并无多余的微风险超声心动图异常或阵发性房颤，随访期间也没有多余的新发房颤或推测的心源性事件。该研究结果提示适当的二级预防，并质疑阵发性房颤为原因不明卒中的重要原因。来源：http://www.thelancet.com/
