Large Artery Disease
CPSD runs several research studies looking into the causes, investigation, and management of large artery atherosclerosis, carotid stenosis, vertebral artery disease and intracranial atherosclerosis.
Large artery atherosclerosis
Atherosclerosis is a term that describes changes in the walls of blood vessels that occur as a result of inflammation and the accumulation of fatty deposits. Areas of atherosclerosis in arteries are often described as "plaques". Atherosclerosis causes arteries to narrow, and this impedes blood flow. These plaques can rupture, causing the formation of blood clots which can block arteries in the brain, heart or leg.
Diseases that can be caused by atherosclerosis include heart attacks, strokes, abdominal aortic aneurysms (AAA), peripheral vascular disease (PVD), and dementia. We are interested in researching the causes of atherosclerotic diseases, their investigation, and management, in order to prevent their occurrence and improve their management.
ABDOMINAL AORTIC ANEURYSM (AAA)
An abdominal aortic aneurysm is an abnormal dilatation caused by weakness of the artery wall, as a result of atherosclerotic damage. The dilated aorta can rupture, causing rapid blood loss, and this is usually fatal. Patients with AAA are monitored and elective surgery can be performed to repair the damage.
We have recently investigated AAA events using data from the Oxford Vascular Study. Our work showed that two-thirds of these AAA events were in patients 75 and older, and those in patients younger than 75 were almost exclusively in male smokers. This work has potential implications for UK AAA screening policy, which is currently offered only to men once, at the age of 65.
Large artery disease causing TIA and stroke
Vertebral artery disease
The vertebral arteries form part of the blood supply to the brain. They run parallel to the spinal cord, up the neck, with the vertebral bones. If there is an occlusion of a vertebral artery, a clot forms, or there is a split in the artery layers (dissection), this can result in a TIA or stroke.
In patients who have had a TIA or stroke caused by narrowing of a vertebral artery, it is unclear whether the best treatment is (a) 'best medical therapy', where they receive a combination of medications to stop the blood clotting, lower cholesterol and blood pressure, or (b) vertebral artery stenting, where, using a catheter inserted into an artery in the leg, a stent can be placed in the vertebral artery to widen it. CPSD has recruited patients to the Vertebral artery Ischaemia Stenting Trial (VIST) to answer this question.
VIST has finished recruiting patients, however patients who were involved are still being followed-up to see which of these approaches best prevents a further stroke or TIA.
Angiography displaying a severely stenosed internal carotid artery, just after the carotid bifurcation
The carotid arteries run up the front of the neck, and divide into the internal and external carotid arteries at the carotid bifurcation. The carotid arteries are crucial for the supply of blood to the brain.
Narrowing of the carotid arteries due to atherosclerosis, known as 'carotid stenosis', causes almost half of all strokes. In patients who have had a TIA or stroke, the diameter of the carotid arteries is commonly assessed. If severely narrowed, a carotid endarterectomy operation may be performed, to widen the artery, improving blood flow to the brain and reducing the risk of stroke.
CPSD research of carotid stenosis and endarterectomy
Research at the Centre for the Prevention of Stroke and Dementia has included:
- Performing large analyses of multiple studies, to demonstrate the benefit of performing carotid endarterectomy within 2 weeks of TIA or stroke symptoms, in patients with severe stenosis
- Creation of a carotid stenosis risk tool, which calculate's an individuals risk of stroke based upon the degree of stenosis and other clinical features
- Analyses of data from the Oxford Vascular Study, which highlighted underinvestigation and undertreatment of carotid stenosis in elderly patients with TIA
- Analyses of the composition of atherosclerotic plaques, removed during carotid endarterectomy surgery, to examine which features are associated with stroke