Long-term results show surgery and stenting are equally protective against stroke resulting from carotid artery disease

Long-term results from the largest randomized trial of stenting and surgery have shown that the procedures are equally protective against stroke resulting from carotid artery disease.

The results were presented at the European Society of Cardiology Congress 2025 in Madrid, Spain, and will give doctors confidence in offering the procedure most suited to their patients.

Stroke is the third 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, which can rupture, causing strokes.

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 performed. Alternatively, the artery may be opened by widening the narrowed artery with a balloon angioplasty, and then a stent added to permanently keep the walls open (carotid artery stenting, CAS).

The Asymptomatic Carotid Surgery Trial 2 (ACST-2) trial enrolled 3,624 participants from 33 countries. Each participant had been diagnosed with carotid artery disease that had not caused a stroke. Participants were randomly allocated to undergo either CAS or CEA, and followed for a median of eight and a half years, with some participants followed for almost 20 years.

Key findings:

• Where both CAS and CEA procedures are feasible treatments for carotid artery disease, they have similar long-term protective effects against stroke;
• • First stroke rates were similar (113 CAS vs. 112 CEA).
  • 91 vs. 92 first strokes remained when first strokes attributed to causes other than carotid artery disease were excluded.
  • There was an excess of non-disabling strokes with CAS, but this excess was entirely due to strokes that, after six months, left either no symptoms or no significant disability.
• Almost all participants had severe stenosis in the ipsilateral (treated) artery but not in the contralateral carotid artery (the artery on the other side), but there were significantly fewer ipsilateral than contralateral strokes (46 vs. 73), confirming the protective effect of both procedures against ipsilateral stroke;
• The ipsilateral artery remained open following either CAS or CEA surgery at one month in over 99% of cases, and during long-term follow-up only 4% in each group required a further ipsilateral procedure;
• For CAS and for CEA the 30-day risk of death or disabling stroke was about 1%.

Alison Halliday, Emeritus Professor of Vascular Surgery at Oxford Population Health and Principal Investigator for ACST-2, 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% within 30 days of surgery.”

Professor Richard Bulbulia, Research Fellow at Oxford Population Health, Consultant Vascular Surgeon, and co-Principal Investigator for ACST-2, said, “Both stenting and surgery are good treatment options, but there may be particular patient factors which favor one approach over another.

“CAS is less invasive, is usually done under local anesthetic, and involves a shorter hospital stay, and may be preferred for those at higher risk of surgical complications—but it had been associated with a higher risk of stroke after the procedure—and CEA was thought to be more appropriate for those with significant artery stenosis.

“These really long-term results from ACST-2 can give doctors confidence in offering the procedure most suited to their patients, knowing that both options are associated with similar very low risks.”

Initial results from the ACST-2 trial showed that there was no significant difference in the risk of adverse, procedure-related events for CAS and CEA and that the number of strokes that occurred in the participants over a five-year follow-up period was similar, but longer follow-up was needed to see whether the similarities remained.

Provided by
Oxford Population Health

Long-term results from the largest randomized trial of stenting and surgery have shown that the procedures are equally protective against stroke resulting from carotid artery disease.

The results were presented at the European Society of Cardiology Congress 2025 in Madrid, Spain, and will give doctors confidence in offering the procedure most suited to their patients.

Stroke is the third 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, which can rupture, causing strokes.

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 performed. Alternatively, the artery may be opened by widening the narrowed artery with a balloon angioplasty, and then a stent added to permanently keep the walls open (carotid artery stenting, CAS).

The Asymptomatic Carotid Surgery Trial 2 (ACST-2) trial enrolled 3,624 participants from 33 countries. Each participant had been diagnosed with carotid artery disease that had not caused a stroke. Participants were randomly allocated to undergo either CAS or CEA, and followed for a median of eight and a half years, with some participants followed for almost 20 years.

Key findings:

• Where both CAS and CEA procedures are feasible treatments for carotid artery disease, they have similar long-term protective effects against stroke;
• • First stroke rates were similar (113 CAS vs. 112 CEA).
  • 91 vs. 92 first strokes remained when first strokes attributed to causes other than carotid artery disease were excluded.
  • There was an excess of non-disabling strokes with CAS, but this excess was entirely due to strokes that, after six months, left either no symptoms or no significant disability.
• Almost all participants had severe stenosis in the ipsilateral (treated) artery but not in the contralateral carotid artery (the artery on the other side), but there were significantly fewer ipsilateral than contralateral strokes (46 vs. 73), confirming the protective effect of both procedures against ipsilateral stroke;
• The ipsilateral artery remained open following either CAS or CEA surgery at one month in over 99% of cases, and during long-term follow-up only 4% in each group required a further ipsilateral procedure;
• For CAS and for CEA the 30-day risk of death or disabling stroke was about 1%.

Alison Halliday, Emeritus Professor of Vascular Surgery at Oxford Population Health and Principal Investigator for ACST-2, 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% within 30 days of surgery.”

Professor Richard Bulbulia, Research Fellow at Oxford Population Health, Consultant Vascular Surgeon, and co-Principal Investigator for ACST-2, said, “Both stenting and surgery are good treatment options, but there may be particular patient factors which favor one approach over another.

“CAS is less invasive, is usually done under local anesthetic, and involves a shorter hospital stay, and may be preferred for those at higher risk of surgical complications—but it had been associated with a higher risk of stroke after the procedure—and CEA was thought to be more appropriate for those with significant artery stenosis.

“These really long-term results from ACST-2 can give doctors confidence in offering the procedure most suited to their patients, knowing that both options are associated with similar very low risks.”

Initial results from the ACST-2 trial showed that there was no significant difference in the risk of adverse, procedure-related events for CAS and CEA and that the number of strokes that occurred in the participants over a five-year follow-up period was similar, but longer follow-up was needed to see whether the similarities remained.

Provided by
Oxford Population Health