Carotid Artery Disease After Stroke (CADAS).

Stroke is a significant medical problem with 150,000 events occurring per year in the UK and incurring healthcare costs of £4 billion per year. Fifty percent of strokes will leave a lasting disability on first manifestation and 10-15% (roughly 16,500 per year) are unheralded ischaemic events in previously asymptomatic Carotid artery disease. Carotid Artery Disease is caused by the formation of an atherosclerotic plaque in the vessel. Stroke or TIA occurs when plaque or adherent thrombus breaks off and embolises to the brain, blocking off its blood supply. Hence, a carotid plaque is said to be symptomatic if it has caused a Stroke or TIA in the territory of the brain supplied by that vessel in the previous six months. Currently, the degree of stenosis (narrowing) of the artery by doppler ultrasound is the main assessment performed. Doppler ultrasound measures stenosis and elevation of blood flow velocity in the artery prior to surgical intervention. However, it has been shown that the degree of stenosis is a poor predictor of stroke as many asymptomatic patients have severe stenosis and many symptomatic patients have moderate stenosis. Stenosis is a two dimensional assessment of a 3-D structure. Other features of the plaque should be considered including the volume of the carotid plaque and its constituents. Carotid Plaque Volume has been measured in 339 individuals, with plaque volume being higher in symptomatic than asymptomatic individuals. In this study, plaque volume did not correlate with stenosis degree. No studies have been conducted measuring the change in carotid plaque volume and morphology following a stroke. This pilot study will perform serial duplex scans on recently symptomatic individuals over a 12 week period and observe the changes in Plaque Volume and morphology. This will attempt to prove that carotid plaque volume is a better predictor of stroke than stenosis. The investigators will also aim to identify other plaque features that may have an important role in predicting stroke risk. Documenting the timescale of change in plaque volume will aid us in defining appropriate timescales for treating the symptomatic population and when those having medical management's risk has returned to baseline. Observing the change in plaque immediately after stroke will improve our knowledge of the changes in plaques that lead to symptoms and may in the future help us predict which patients with asymptomatic carotid stenosis need operation.