Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

Results from a major clinical trial demonstrate that both stenting and surgery are low-risk and similarly effective procedures for treating carotid artery disease.

" "

The results, published today in The Lancetwere announced simultaneously at the European Society of Cardiology Congress 2021.

Stroke is the second largest cause of death worldwide, responsible for over six million deaths each year. A common cause of stroke is carotid artery disease (also known as carotid artery stenosis), where the large blood vessels that supply oxygen to the brain become narrower. Usually, this is due to deposits of fatty material (atherosclerosis) in the arteries which eventually form hardened plaques.

To reduce their risk of having a deadly stroke, patients with carotid artery disease may undergo one of two different procedures to open up the affected artery and improve blood flow to the brain. Carotid artery surgery, also called carotid endarterectomy (CEA), involves surgically removing the plaque, and is more commonly prescribed. Alternatively, the artery may be opened by inserting a catheter with an inflatable balloon tip, and then a stent added to permanently keep the walls open (carotid artery stenting, CAS).

Up to now it has been unclear which of these procedures results in better overall patient outcomes. This includes both the long-term protective effect against strokes, and the risk of an adverse event happening during or immediately after the operation.

To generate robust evidence that could answer this, researchers have coordinated the Asymptomatic Carotid Surgery Trial 2 (ACST-2), the largest trial to date comparing CAS and CEA. The trial, hosted by the Nuffield Department of Population Health at the University of Oxford, enrolled 3,625 participants from 33 countries. Each participant had been diagnosed with carotid artery disease that had not caused  a stroke.

After agreeing to take part in the study, participants were randomly allocated to undergo either CAS or CEA, and followed up for an average of five years. The main outcomes assessed by the trial were adverse events associated with the procedure itself, and the long-term protective effect against strokes.

Key results:

  • There was no significant difference in the risk of adverse, procedure-related events for CAS and CEA. For both treatments, 1% of patients had a disabling stroke or died within 30 days (15 in the CAS group and 18 in the CEA group) and 2% had a non-disabling stroke (48 in the CAS group and 29 in the CEA group).
  • The number of strokes that occurred in the participants over the five-year follow up period was similar for CAS and CEA. Fatal or disabling stroke occurred in 2.5% of patients in each group, and the total number of strokes was 5.3% in the CAS group, and 4.5% in the CEA group.

Principal Investigator for ACST-2 Professor Alison Halliday, Professor of Vascular Surgery in the Nuffield Department of Surgical Sciences, University of Oxford, said: ‘We have shown that, for patients with a severely narrowed carotid artery, stenting and surgery have similar effects on the chances of having a disabling or fatal stroke. The risk from each procedure is about 1%. After that, however, the annual risk over the next five or more years is halved, from 1% down to 0.5% per year.’

Mr Richard Bulbulia, a Consultant Vascular Surgeon, Co-Principal Investigator for ACST-2, and Research Fellow at the Nuffield Department of Population Health, said: ‘Both stenting and surgery are good treatment options, but there may be particular patient factors which favour one approach over another. Until now, it had been unclear if CAS or CEA results in better overall outcomes on the risk of stroke. The evidence from this trial can give doctors confidence in offering the procedure most suited to their patients, knowing that both options are associated with similar very low risks.’

Similar stories

Genetic mapping of tumours reveals how cancers grow

Researchers from the University of Oxford, KTH Royal Institute of Technology, Science for Life Laboratory, and the Karolinska Institutet, Solna, Sweden, have found that individual prostate tumours contain a previously unknown range of genetic variation.

Two NDS researchers receive prestigious MRC Clinical Research Training Fellowships

Miss Catherine Lovegrove and Dr Alexander Sagar from the Nuffield Department of Surgical Sciences (NDS) have been awarded highly competitive Clinical Research Training Fellowships by the Medical Research Council (MRC).

WHO Classification of Tumours programme awarded large grant to improve classification and evidence base

A new project titled Mapping the Evidence for the World Health Organization (WHO) Classification of Tumours: A Living Evidence Gap Map by Tumour Type (WCT EVI MAP), led by researchers of the WHO Classification of Tumours programme at the International Agency for Research on Cancer (IARC), has received a grant of €3.5 million from the European Commission. This four-year project, which will be undertaken in collaboration with six other international institutions, including Oxford University's Nuffield Department of Surgical Sciences (NDS), was launched on 1 July 2022.

Blog posts

Oxford MedSci goes silver: 10 Years of Athena SWAN

The Medical Sciences Division is celebrating 10 years since its first Athena Swan bronze application, and the first year in which all 16 of its departments have achieved a silver award. The silver award recognises commitment to gender equality, understanding culture and context, and more. Read about our department’s hard work and innovation.

Lights, camera, action! My journey into video production

Dr Hannah McGivern provides a 'behind-the-scenes' account of her experience producing the video 'Journey of a QUOD Sample: Donating to Transplant Research', supported by the funds from the University of Oxford Public Engagement with Research (PER) Seed Fund.

Mentoring in practice

NDS has launched a new, interdepartmental mentoring scheme called RECOGNISE. In this podcast, Gemma Horbatowski (HR Advisor) interviews Monica Dolton (Programme Manager and Research Project Manager) about her experiences of mentor-mentee relationships.