Extracellular Vesicles and Dysregulated Coagulation in the Prediction of Stroke

The inclusion criteria for phase 1 (initial patient recruitment) will be: 1. Patients with or without diagnosis of TIA made by a physician working in stroke medicine, sufficiently so to start post-TIA care or so that no further investigation is thought necessary to confirm or refute the diagnosis. 2. TIA confirmed patient has been prescribed antiplatelet drugs or anticoagulants. 3. Patients must be aged \> 18 years. 4. Patients are taking an ordinary diet by mouth. The inclusion criteria for phase 2 (patient representing with stroke) will be: 1. Radiological evidence, on CT and/or MR imaging of the brain of cerebral infarction, with or without secondary haemorrhage. 2. The underlying mechanism of cerebral infarction is embolic from a cardiac source (e.g. atrial fibrillation), atherothromboembolic (from aorta or other large vessels in the neck) or in-situ thrombosis. No further investigations are thought necessary to confirm or refute the diagnosis. 3. No further investigations are thought necessary to confirm or refute the diagnosis. 4. Patients must be aged \>18 years. 5. Patients must not be pregnant or breast feeding. 6. Patients are taking an ordinary diet by mouth. Exclusion Criteria The Exclusion criteria for phase 1 (initial patient recruitment) will be: 1. Inability to give consent. 2. Inability to feed by mouth. 3. Short life expectancy. 4. Pregnancy or breastfeeding. 5. Symptoms are readily explained by medical problems not involving focal cerebral ischaemia. The Exclusion criteria for phase 2 (patient representing with stroke) will be: 1. Patients who have not previously given consent for follow up blood sampling. 2. Patients who are unable to feed by mouth. 3. Patients in whom life expectancy is short. 4. Patient is pregnant or breast feeding.