Extracts from "Clinical Evidence": Acute ischaemic stroke

Abstract

Definition Stroke is characterised by rapidly developing clinical symptoms and signs of focal, and at times global, loss of cerebral function lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin.1 Ischaemic stroke is defined as stroke due to vascular insufficiency (such as cerebrovascular thromboembolism) rather than haemorrhage. #### Interventions Acute ischaemic stroke ##### Beneficial: Stroke units Aspirin ##### Trade-off between benefits and harms: Thrombolytic treatment ##### Likely to be ineffective or harmful: Immediate systemic anticoagulation Acute reduction of blood pressure Intracerebral haematomas ##### Unknown effectiveness: Evacuation Incidence/prevalence Stroke is the third most common cause of death in most developed countries.2 It is a worldwide problem: about 4.5 million people die from stroke each year. Stroke can occur at any age, but half of all strokes occur in people over 70 years old.3 Aetiology About 80% of all acute strokes are caused by cerebral infarction, usually resulting from thrombotic or embolic occlusion of a cerebral artery4; the remainder are caused either by intracerebral or subarachnoid haemorrhage. Prognosis About 10% of all people with acute ischaemic strokes will die within 30 days of stroke onset.5 Of those who survive the acute event, about 50% will experience some level of disability after six months.6 Aims To achieve rapid restoration and maintenance of blood supply to the ischaemic area in the brain, and to minimise brain damage and hence impairment, disability, and secondary complications. Outcomes Risk of death or dependency (generally assessed as the proportion of people dead or requiring physical assistance for transfers, mobility, dressing, feeding, or toileting three to six months after stroke onset7); quality of life. Clinical Evidence researchers searched the Cochrane Library and the Cochrane Stroke Review Group database in 1998 and performed an update search and appraisal for systematic reviews and subsequent randomised controlled trials (RCTs) in June 1999. Question: What …