Cerebral embolism in the perioperative period in patients post interventional treatment of carotid artery stenosis: a preliminary report.

Background: During carotid revascularisation, embolic material originating from unstable atherosclerotic plaques and thrombi forming within the stent is generated. The significance of a cerebral embolism in the first days after restoring the patency of the arteries has not been established.
Aim: To evaluate the occurrence of microembolic signals in the middle cerebral artery on the day preceding, and on the second day after, endarterectomy and angioplasty with stenting of the ipsilateral internal carotid artery.
Methods: The study included 44 patients (mean age: 68.46 ± 6.2 years; 28 men and 16 women) in whom endarterectomy (31 patients) or stenting (13 patients) were performed due to internal carotid artery stenosis ≥ 70%. All of the patients had their history taken and underwent physical as well as neurological examinations; they also had complete blood count tests, transcranial ultrasound, duplex Doppler ultrasound of carotid and vertebral arteries including evaluation of the degree of stenosis and the morphology of atherosclerotic plaques. In addition, cerebral embolism in the middle cerebral artery was detected in them in the period preceding the intervention and on the second day after the intervention.
Results: The incidence of microembolic signals before and after the procedure was not significantly different in patients who underwent endarterectomy and stenting (38% and 53.5%, respectively, p > 0.05). There was no occurrence of stroke, and the periprocedural frequency of other neurological events did not differ significantly between patients depending on the type of revascularisation. In patients with symptomatic carotid artery stenosis, compared to individuals with asymptomatic stenosis, microembolic signals were detected significantly more frequently on the second day (63.2% vs. 28%, p = 0.0197) after the intervention. Furthermore, in these patients, microembolic signals of a frequency > 10 dB were found significantly more often (63.2% vs. 8%, p = 0.0001). In patients with microembolic signals of intensity > 10 dB, elevated thrombocyte counts were observed significantly more frequently compared to patients with lower intensity signals (80% vs. 25.6%, respectively, p = 0.01). Patients with symptomatic carotid stenosis significantly more frequently used statins prior to hospitalisation (84.3% vs. 52%, p = 0.0256). Symptomatic internal carotid artery stenosis (55.2% and 20.0%, respectively, p = 0.02) and microembolic signals after intervention (55.2% and 20.0%, respectively, p = 0.02) were observed significantly more frequently in patients using statins in the preoperative period than in patients not taking these medications.
Conclusions: 1. Microembolic signals in the middle cerebral artery detected with the use of transcranial ultrasound examination in the early period after carotid revascularisation of the internal carotid artery are usually asymptomatic. 2. Cerebralembolism in the early period after carotid revascularisation is more frequently found in patients with symptomatic carotid artery stenosis subjected to a repair procedure. 3. The clinical significance of cerebral emboli found after carotid revascularisation requires further research.