Carotid Artery Procedures Don't Boost Brain Function, Study Finds

In a groundbreaking study presented at the American Stroke Association's International Stroke Conference 2026, researchers have found that surgical procedures to improve blood flow to the brain in patients with carotid artery stenosis do not lead to better cognitive function compared to medication and lifestyle changes alone. The CREST-2 trial substudy, led by Professor Ronald M. Lazar from the University of Alabama at Birmingham, involved over 2,000 adults with asymptomatic but significant carotid artery blockage. The study compared three approaches: intensive medical management alone, medical management combined with carotid endarterectomy (a procedure to remove plaque), and medical management plus stenting to prop open the narrowed artery. After an average follow-up of 2.8 years, researchers discovered no difference in thinking or memory skills among the treatment groups, challenging previous assumptions that restoring blood flow would enhance cognitive performance.

The findings, presented as preliminary research at the world's premier meeting for stroke and brain health science, suggest that healthcare professionals should adjust how they counsel patients about treatment expectations. While procedures like carotid endarterectomy and stenting remain valuable for reducing stroke risk, they should not be promoted as methods to improve cognition. The study's cognitive core component, which assessed participants before treatment and annually for up to four years, represents the first large randomized controlled trial to include cognition as a major outcome measure in carotid stenosis research. Interestingly, the research confirmed that cognitive decline did occur in participants who experienced strokes during the study, validating the sensitivity of the assessment methods.

According to Mitchell Elkind, the American Heart Association's Chief Science Officer for Brain Health and Stroke, these results indicate that restoration of blood flow through large vessels alone may not address the complex pathways to cognitive decline, including inflammation, neurodegeneration, and small vessel disease. The study authors note that worsening cognition over time may signal the need to re-evaluate and adjust treatment, even if the initial procedures don't provide cognitive benefits. The research, which builds on 2021 findings published in Stroke journal, opens new questions about whether reduced blood flow is the primary cause of cognitive decline in carotid artery disease or if other factors like small particles traveling to the brain play a more significant role.