Pre-stroke Cognitive Status and Thrombolytic Therapy

At the acute stage of cerebral ischaemia, the only effective drug that increases the proportion of patients who survive without dependency is thrombolytic therapy by intravenous (i.v.) tissue-plasminogen activator (t-PA). This treatment is entered into routine practice with similar results than in trials, in various places of the world including Europe and Japan. Stroke and dementia are closely related. About one patient in ten has dementia before a first-ever stroke, and more than one in three has dementia after a recurrent stroke. Pre-existing dementia is associated with a worse outcome of stroke, and pre-existing cognitive impairment without dementia is associated with a higher rate of institutionalisation within 3 years. In many patients cognitive impairment is due to the summation of the effects of vascular and Alzheimer lesions of the brain. More and more patients nowadays who are eligible for rt-PA are already known as demented at admission. A retrospective study conducted in a cohort of patients with dementia who had an ischaemic stroke and were treated by rtPA suggested that there is no increased risk of cerebral bleeding and death as compared with non demented patients. However, pre-existing cognitive impairment is possibly associated with (i) an increased risk of bleeding in patients with cognitive impairment, and (ii) a higher sensitivity to the neurotoxic effect of rt-PA on the brain tissue. Japanese patients differ from European patients by a higher risk of spontaneous intracranial haemorrhage, and a higher proportion of patients with small-vessel diseases. The primary objective of the OPHELIE-COG study is to determine whether ischaemic stroke patients who are treated with i.v. rt-PA are more likely to have a poor outcome (defined as a modified Rankin scale 2 to 6 at month 3) in the presence of pre-existing cognitive impairment or dementia. The secondary objectives are to determine whether (i) they have an increased risk of symptomatic intracerebra