Large prospective cohort studies to describe the long-term stroke risk associated with carotid artery disease
Professor Alison Halliday, Nuffield Department of Surgical Sciences
Around 20% of strokes are caused by carotid artery disease, half of which are disabling or fatal. Such strokes can be prevented with good triple medical therapy and by selective carotid surgery, with three large RCTs showing that successful carotid intervention halves the long-term risk of stroke in asymptomatic patients.
However, these three trials were conducted several decades ago with sub-optimal background medical therapy. Small highly selective cohort studies suggest that the contemporary stroke risk associated with an un-operated carotid stenosis is lower than that seen in these trials, leading some to believe that the risks of intervention are not justified.
To provide a reliable estimate of carotid-related stroke risks, we will recruit ~10,000 patients undergoing carotid duplex scanning in vascular laboratories across the UK to a large streamlined prospective cohort study – The UK Carotid Cohort Study (UKCCS). A pilot study in two large vascular units is underway and the study design allows rapid recruitment, with long-term low-cost follow-up via routinely collected electronic health records. An imaging sub-study is also planned, with carotid plaque MRI scanning to investigate the association between various plaque characteristics with stroke. Finally, we will investigate the association of carotid artery disease with impaired cognitive function and the development of dementia.
We also plan to pool individual participant data from UKCCS with other large prospective studies of patients with carotid artery disease in the Carotid Prospective Studies Collaboration (CPSC).
research experience, methods and training
- Building a network of >20 collaborating vascular laboratories across the UK, ensuring rapid recruitment within 2-3 years
- Data cleaning of baseline demographics
- Assessing cognitive function at baseline
- Establishing the CPSC and building a unified dataset
Four major outputs are envisaged from this DPhil:
- A methodology paper describing the streamlined study design for recruitment, follow-up and stroke phenotyping.
- A baseline paper describing the UKCCS population and (if sufficient patient-years’ follow-up available) early stroke rates.
- A baseline paper describing plaque characteristics in the MRI sub-study (in collaboration with Professor Robin Choudhury).
- Pooled analyses of all large scale carotid cohort studies.
Vascular Surgeons, Stroke Physicians or Neurologists with an interest in carotid disease and stroke prevention.