<prompt> In a patient with ischaemic stroke, intravenous recombinant tissue has mainly been found to be useful during the initia3 hours6 hours12 hours24 hours  <response>: Ischemic stroke occurs when a blood clot blocks or plugs an aery leading to the brain. A blood clot often forms in aeries damaged by the buildup of plaques atherosclerosis. It can occur in the carotid aery of the neck as well as other aeries. Ref Harrison20th edition pg 1123 