Cerebral Haemodynamics in Transient Ischaemic Attack

Adequate brain blood flow is essential for brain survival and function. Brain blood flow is kept relatively constant by a process called cerebral autoregulation (CA). CA is impaired in various diseases including head injury, diabetes, Alzheimer's, pre-eclampsia and stroke. In stroke, impaired CA is associated with poor outcomes. A transient ischaemic attack (TIA) is the same as a stroke, except the symptoms only last for a short amount of time and resolve spontaneously. TIAs are sometimes called mini-strokes and are a major warning sign of strokes. There have been lots of studies of CA in stroke, but very few studies of CA in TIA. Brain blood flow and CA can be studied non-invasively with Transcranial Doppler ultrasound (TCD). Study aim: To investigate whether CA is impaired in patients with TIA 20 patients with acute TIA (within 7 days), and 20 healthy controls will be recruited from the specialist TIA clinic at University Hospitals of Leicester NHS Trust. Participants will be eligible if they are aged over 18 and can consent to participate. They won't be able to participate if they have severe heart failure, an irregular heartbeat, blocked neck blood vessels, severe breathing problems, or if they are pregnant. Participants will undergo an assessment of brain blood flow using TCD, during which their heart rate, breathing and blood pressure will also be monitored. During the assessment participants will sit quietly before being asked to stand and then complete a squat-stand manoeuvre in time with a computer sequence. The research visit will take approximately 90 minutes, the assessment itself will take approximately 1 hour and participants only need to attend once.