Transient ischaemic attack preceding anterior circulation infarction is independently associated with favourable outcome

Experimental studies in various animal models have provided evidence that short episodes of global or focal ischaemia partially protect the brain against subsequent ischaemic damage. The term “ischaemic tolerance” has been established for this phenomenon, both in the cerebral circulation and in other organs (see recent review by Kirino1). There are only a few clinical reports supporting the notion that ischaemic tolerance may also exist in stroke patients who have had a short episode of focal cerebral ischaemia—that is, a transient ischaemic attack (TIA) prior to cerebral infarction.2,3 The purpose of the present study was to investigate the association between the outcome of anterior circulation infarction and prior TIA in stroke patients from a large scale multicentre stroke registry. The ASH (Arbeitsgruppe Schlaganfall Hessen) database is a prospective hospital based stroke registry for the federal state of Hesse in Germany. This registry covers all stroke units (nine neurological hospitals) in this state with the obligation to include all patients presenting with cerebral ischaemia or intracerebral haemorrhage. Thus, ~90% of stroke patients treated in these hospitals from 1998 to 2000 are included in the ASH database with 12 571 complete datasets (2960 with TIA, 8484 with cerebral infarction, 1127 with intracerebral haemorrhage). Patients with proven anterior circulation infarction (computed tomography (CT) or magnetic resonance imaging (MRI) scan) were …