Silent Micro-Infarct in Carotid Artery Stenting: Who Has it and Why?

Aim: To compare the postprocedural cerebral diffusion-weighted imaging (DWI) findings in cases of carotid stenosis (CS)-related carotid plaques in terms of plaque morphology, degree of stenosis, and the use of a distal protection filter. Moreover, we used DWI to assess the asymptomatic cerebral embolism rates during carotid artery stending (CAS) operations performed for noncalcified versus calcified carotid plaques.

Material and methods: Our study included 99 patients admitted to the Ankara City Hospital Stroke Center in 2022. All of our patients have been evaluated and scheduled for CAS as a result of a decision made by the council. Cases of stenosis of > 50% in symptomatic patients and > 70% in asymptomatic patients were included. The patients were grouped according to their Doppler ultrasonography results. All of the patients underwent DWI within the first 24 hours after the procedure, and then two groups of patients were compared.

Results: A statistically significant difference was found between the distributions of the presence of silent micro-infarcts on DWI in terms of plaque characteristics (p < 0.001). In the patients with normal DWI findings, the percentage of calcified plaques was 38.7%, while the percentages of hypoechoic plaques, plaques with low echogenicity, and ulcerated plaques were 91.3%, 85.7%, and 78.8%, respectively. The rates of calcified plaques and ulcerated plaques differed in the group of patients with silent microinfarcts. The rate of silent micro-infarcts was 61.3% in the patients with calcified plaques, 8.7% in those with hypoechoic plaques, 14.3% in those with low-echogenicity plaques, and 21.2% in those with ulcerated plaques.

Conclusion: The study found that carotid stents implanted in calcified and ulcerated plaques had a higher correlation with the presence of periprocedural asymptomatic ipsilateral DWI findings than those implanted in hypoechoic plaques and low-echogenicity plaques.