Ischaemic strokes and treatment with thrombolysis: The key lies with paramedics
The treatment availableIn the case of an embolic cause, which creates an ischaemic stroke, alteplase (Actilyse® manufactured by Boehringen Ingelheim) can be used—this is a drug developed to break down clots. Although anticoagulants such as heparin decrease the growth in size of a clot in an artery, thrombolytic agents such as alteplase actively reduce the size of the clot. This works by activating the production of plasmin from its precursor plasminogen. Plasmin degrades fibrin, which is a substance activated in the coagulation cascade; the system the body uses to produce blood clots in order to stem bleeding. This is known as fibrinolysis.There is a time limit for the administration of such a treatment, because the affected brain cells die after approximately three hours, and the damage is irreversible—leading to a situation in which the risks of undertaking thrombolysis provide no net benefit to the patient.The main risk is of a symptomatic intracerebral haemorrhage. Of note to all healthcare professionals is that this commencement of treatment threshold has recently been revised up by NICE (National Institute for Health and Clinical Excellence). ECASS III was a Europe-wide trial from 19 countries with 821 patients.It involved the randomised, placebo-controlled administration of altepase between 3–4.5 hours from stroke onset. Published in 2008, it has been accepted into the September 2012 NICE guidelines (NICE technology appraisal guidance 264) as it is now clinically justifiable to treat patients up to 4.5 hours from the onset of their stroke—in line with a more favourable outcome overall for the treated group.Figure 1.A demonstration of the mechanism which can lead to an artheroscerotic plaque in a cranial vessel causing thrombosis and occlusion of the artery. High blood lipids are clinically a good indicator of increased risk of ischaemic stroke.