Analysis of cerebral microemboli in relationship to carotid stenosis degree and plaque type

The objective of this study was to assess the prevalence and acoustic properties of cerebral emboli in patients with extracranial carotid artery stenosis in relationship to carotid stenosis degree and plaque type. A total of 39 patients (27 men and 12 women, aged 58+/- 17 yrs) with extracranial carotid artery stenosis was examined by color coded duplex sonography. The patients were divided into 3 groups according to carotid stenosis degree: mild (0-29 perceent), moderate (30-69 percent) and severe (70-99 percent) ; and according to plaque type also into 3 groups: soft, calcified and fibrous. Simultaneous TCD monitoring of both a.cerebri media was performed over 60 minutes. Detected emboli signals were categorised into 3 groups according to the intensity of the Doppler amplitude. Examination of 78 internal carotid arteries revealed in 24 mild stenosis, in 31 moderate and in 17 severe stenosis, while total occlusion was found in 6 arteries. Emboli signals were detected in 15 patients (38.5 percent). In patients with mild stenosis no emboli were detected. In patients with moderate stenosis with soft plaque, 4 from 9 (44.4 percent) were emboli positive, as well as 5 from 18 (27.7 percent) patients with fibrous plaque. In patients with a severe stenosis, all patients with soft plaques (4) had detectable emboli signals, and 6 out of 13 (46.2 percent) with fibrous plaques. Most of the detected emboli signals were placed in lower intensity groups of the Doppler amplitude.