Carotid artery stenosis can result in the brain tissue injury related to the intracranial aterial flow disturbances as well as microembolic complications. The choice of the proper therapy in patients with carotid artery stenosis, especially asymptomatic, remains still a significant clinical problem. The study aim was an assessment of the cerebral embolism and brain vascular reserve parameters in patients with carotid artery stenosis regarding the occurrence of the clinical symptoms, the degree of stenosis as well as plaque morphology.

The study included 60 patients, with internal carotid artery stenosis. The degree of stenosis, the atherosclerotic plaque surface and morphology were assessed by the means of Duplex Doppler ultrasound. Cerebrovascular reactivity (vasomotor reactivity reserve test and Breath Holding Index) and monitoring of the microembolic signals (MES) were assessed with transcranial Doppler ultrasound examination (TCD).

The vasoreactivity parameters were significantly lower in the group of patients with stenosis ≥70% and in patients with ulcerations on the plaque surface. Microembolic signals were recorded significantly more often in symptomatic patients; in patients with stenosis ≥70%; in patients with ulcerations on the plaque surface and those with hypoechogenic plaque structure.

Microembolic signals in patients with symptomatic carotid stenosis are one of the ultrasound features of unstable carotid stenosis. Worse reactivity parameters of the cerebral arteries are associated with the presence of a large degree of carotid artery stenosis.