Dear colleagues, I am Christoph Diener, from the Faculty of Medicine at the University of Duisburg-Essen in Germany. My video this month concentrates on one important topic only, and this is the management of asymptomatic carotid stenosis.
Defining Asymptomatic Carotid Stenosis
Asymptomatic stenosis of the internal carotid artery is defined as a stenosis of 50% or more,and these stenoses are usually found at the origin of the internal carotid artery. Asymptomatic carotid stenosis can lead to ischemic strokes caused by embolization from an ulcerated plaque, or very rarely, hemodynamically, if an occlusion of the internal carotid artery occurs.
How are these stenoses identified usually? During screening examinations that people who have coronary artery disease or peripheral arterial disease undergo, or when those older than 60 or 65 years see their internist for a yearly checkup.
The first studies comparing optimal drug therapy with carotid endarterectomy were conducted in the 1990s and the early 2000s, and these were the ACAS and ACST studies. At that time, the best possible medical treatment consisted of administrating aspirin and treating arterial hypertension.
The annual risk for ipsilateral stroke, perioperative stroke, or death over 5 years in the ACAS study was 5% for patients who underwent endarterectomy and 11% for patients who received best medical treatment. This translated to a 53% risk reduction in favor of carotid surgery, and at that time, carotid surgery was recommended.
Subsequently, a number of additional studies were done comparing surgical treatment with optimal medical therapy. These included between 450 and 3600 patients, and the absolute risk reduction in favor of surgery over best medical treatment was variable, ranging from, in an optimal case, 5.4% to only 3.3%, which was no longer statistically significant.
In the next 10 years, seven randomized studies involving almost 6000 patients were conducted comparing carotid surgery with carotid stenting. In a meta-analysis, no differences were found for the endpoints of death, stroke, and myocardial infarction. Carotid surgery showed a slight superiority for the endpoint of ipsilateral stroke.
Since 1990, medical treatment has dramatically improved. In addition to antiplatelet drugs and better antihypertensive drugs, we now have much better medications available for treating elevated glucose levels and diabetes, medications for treating lipid metabolism disorders, obesity treatment, and the management of risk factors, like programs for smoking cessation, regular physical activity, and healthy diet.
As a result, the 5-year risk for stroke has fallen from 11% in the 1990s to 2.5% in 2026. There are also predictors of increased stroke risk in people with asymptomatic carotid stenosis, and these include high-degree stenosis of more than 80%, evidence of microembolism in transcranial Doppler, plaque ulceration in duplex sonography, progressive stenosis of the internal carotid artery, and clinically silent infarct on MRI of the brain.
Enter CREST-2 at ISC
The purpose of this video is the publication of the CREST-2 study in The New England Journal of Medicine and the presentation of the study at the International Stroke Congress. This was by far the largest and best planned and -conducted study comparing best medical therapy and carotid stenting in 1245 patients, with carotid endarterectomy in 1240 patients. The primary endpoint was stroke or death, and this was 6% for best medical therapy and 2.8% for stenting. This corresponds to a relative risk reduction of 3.2%, which was statistically significant.
For carotid surgery, the rate of stroke and death was 5.3% vs 3.7%, so the relative risk reduction was 1.6%, and this was statistically not significant. If we calculate numbers needed to treat, these were 31 for stenting compared to best medical therapy, and 63 for carotid surgery compared to best medical therapy.
The CREST-2 study also showed that carotid stenting is associated with a slightly higher therapeutic benefit compared to best medical treatment. No superiority for cardiac surgery over optimal medical treatment was observed. The low risk for ipsilateral stroke is noteworthy. This risk ranged between 0.4% and 1.7% per year across all four groups of therapy.
In contrast to earlier studies, the CREST-2 study excluded myocardial infarction as an endpoint, and this makes sense because carotid surgery or carotid stenting usually has no impact on the risk for myocardial infarction.
Caveats and Limitations of CREST-2
Unfortunately, serious bleeding complications were not reported in the study. And these are relevant because after carotid stenting, dual antiplatelet therapy has to be administered at least for a few weeks.
It is also important to note that there was a rigorous selection of vascular surgeons and interventionalists, and this might not translate into everyday clinical practice because we can expect that probably most people who do not have a high load of procedures have a higher complication rate.
The periprocedural risk was 1% for stroke. This study very closely monitored the management of risk factors and the treatment of concomitant diseases, and in everyday clinical practice, this might not always be achieved.
When a physician discusses with a patient with asymptomatic carotid stenosis or the family, then they have to point out that the initial risk for stroke and death from the procedure itself is about 1.3%, and this must be weighed against the long-term benefit of stenting, where the risk reduction over 5 years is 3.2%. The presence of risk factors for an increased risk for stroke that I have mentioned before should also be taken into account when deciding for or against surgery or stenting of the internal carotid artery.
In summary, the CREST-2 study is by far the best planned and -conducted study for the management of asymptomatic carotid stenosis. If one decides to perform a procedure, then it should be carotid stenting and not carotid surgery. (I would never do either unless YOUR DOCTOR COMPLETELY GUARANTEES NO PROBLEMS!
Here is why you do neither of those options!
In my non-medical opinion, verify the Circle of Willis is complete, then close up the offending artery. I functioned extremely well for 13 years with only three arteries feeding the Circle of Willis)
Dear colleagues, ladies and gentlemen, this was the management of asymptomatic cardiac stenosis and the status of knowledge in 2026. I'm Christoph Diener from the Faculty of Medicine at the University of Duisburg-Essen. Thank you very much for listening and watching.
