小脑梗塞的机理

小脑是后颅窝最大的脑组织。然而,直到本世纪80年代人们才对小脑梗塞有所了解。由于CT和MRI能充分显示小脑病变,现在人们可以将区域性梗塞(包括小脑动脉的全区域及其分支各区域和交界区梗塞区别开来,这有助于推测缺血性梗塞的血管性机理。区域性梗塞是因血栓栓塞引起,心脏栓子最为常见,其次是动脉-动脉栓塞、椎动脉(VA)(主要是颅内段)或基底动脉(BA)粥样硬化和椎动脉剥离,从治疗方面看,其中椎动脉病变引起的动脉内栓塞值得重视。交界区或终未区梗塞可能是由血液动力学改变或小的栓塞引起。最为常见的原因是血管粥样化或血栓引起的椎动脉或基底动脉的闭塞;其次是高凝状态(如血小板增多症、红细胞增多症、DIC),椎基底动脉或其颅内血管粥样化引起的小的或终末(软膜)动脉病;全身低血压很罕见。评价颅内血液动力学的神经成像新方法(TCD、MRA、PET、SPECT)为进一步研究这些患者及其病变的自然病程和进一步确定各种治疗方案和血管重建措施提供了机会。

Rationale and design of a randomised double-blind 2×2 factorial trial comparing the effect of a 3-month intensive statin and antiplatelet therapy for patients with acute mild ischaemic stroke or high-risk TIA with intracranial or extracranial atherosclerosis(INSPIRES)

Background It remains unclear if intensive antiplatelet and statin treatments begun within 24-72 hours of cerebral ischaemic events from intracranial or extracranial atherosclerosis is effective or safe.Methods The Intensive Statin and Antiplatelet Therapy for High-risk Intracranial or Extracranial Atherosclerosis(INSPIRES)trial is a randomised,double-blind,placebo-controlled,multicentre and 2×2 factorial trial.6100 individuals between the ages of 35 and 80 who have experienced a mild ischaemic stroke or high-risk transient ischaemic attack(TIA)within the previous 72 hours that is attributed to≥50%atherosclerotic stenosis of a major intracranial or extracranial artery or multiple infarctions of atherosclerotic origin will be enrolled in the trial.Eligible subjects will be randomised 1:1:1:1 to one of four groups:(1)intensive antiplatelet therapy(combined clopidogrel and aspirin for days 1-21,then aspirin placebo and clopidogrel for days 22-90)plus immediate intensive statin therapy(atorvastatin at a dose of 80 mg daily for the first 21 days,then 40 mg daily for days 22-90);(2)intensive antiplatelet therapy plus delayed intensive statin therapy(atorvastatin placebo for days 1-3,followed by 40 mg per day of atorvastatin for days 4-90);(3)standard antiplatelet therapy(combination of clopidogrel placebo with aspirin for 90 days)plus immediate intensive statin therapy and(4)standard antiplatelet therapy plus delayed intensive statin therapy.The primary efficacy endpoint is any new stroke(ischaemic or haemorrhagic)within 90 days after randomisation.The primary safety endpoint is moderate to severe bleeding at 90 days.Conclusion The INSPIRES trial will assess the efficacy and safety of intensive antiplatelet therapy and immediate intensive statin therapy begun within 72 hours of onset in decreasing the recurrent stroke at 90 days in patients with acute mild ischaemic stroke or high-risk TIA of intracranial or extracranial atherosclerosis origin.

轻型缺血性卒中或短暂性脑缺血发作的早期双联抗血小板治疗

王拥军及同事探讨了应用双联抗血小板治疗预防卒中复发或短暂性脑缺血发作的最新证据。轻型缺血性卒中和短暂性脑缺血发作(TIA)患者在头几周内有较高的卒中及其他血管事件的复发风险(5%~11.7%严。双联抗血小板治疗,包括氯吡格雷和阿司匹林,是减少卒中复发的有效治疗策略Magic Group的专家小组(http://magicproject.org/)最近在The BMJ中发表了一个强烈的快速推荐建议,即对于轻型缺血性卒中和TIA患者应在症状出现24小时内开始双联抗血小板治疗,并持续10~21天3。

新英格兰医学中心后循环登记

在407例新英格兰医学中心后循环登记患者中，59%为不伴TIA的卒中，24%在卒中前有TIA，16%仅表现为TIA。栓塞是最常见的卒中机制（占40%，其中24%为心源性栓塞，14%为动脉-动脉栓塞，2%两者兼有）。在32%的患者中，大动脉闭塞性损害导致血流动力学性脑缺血。梗死最常出现在后循环远段供血区（脑干腹侧、小脑上部以及枕叶和颞叶），近段（延髓和小脑后下部）和中段（桥脑和小脑前下部）供血区受累的比例相当。148例患者存在至少累及1支大动脉的重度闭塞性损害（狭窄〉50%），134例患者有单侧或双侧动脉受累。最常见的闭塞部位是椎动脉颅外段（52例患者，15例双侧）、椎动脉颅内段（40例患者，12例双侧）和基底动脉（46例患者）。动脉-动脉栓塞是椎动脉闭塞性疾病患者最常见的脑梗死发病机制。30d病死率为3.6%。发病机制为栓塞，远段供血区受累和基底动脉闭塞性疾病患者的预后最差。具有多处动脉狭窄部位的患者转归最好。他们通常经年累月地发生TIA。