There has been a drop in the number of patients having the most common form of stroke prevention surgery, a new study has found.
Researchers say people are being put off having the carotid endarterectomy surgery for the wrong reasons.
They credit the drop with highly publicised randomised controlled trials (RCTs) which highlighted the inappropriate use of the surgery.
The New York Carotid Artery Surgery (NYCAS) was based on nearly 1,000 carotid endarterectomy surgeries, which involves opening a neck artery to remove plaque build up, on elderly patients and was published in the American Academy of Neurology journal.
"Though RCTs are time-consuming, expensive and logistically challenging, our findings suggest that they played a role in improving the appropriate use of carotid endarterectomy," said the study's author Ethan Halm, an associate professor at New York's Mount Sinai School of Medicine.
The most common inappropriate reason for performing the surgery was that patients with other medical problems but no symptoms from blocked arteries were at high risk of surgical complications.
Over 130,000 people in England and Wales have a stroke every year, according to figures from the Stroke Association.