Background: The use of modern methods of cerebral blood perfusion monitoring during carotid endarterectomy, including transcranial doppler ultrasonography, improved the efficacy of surgical treatment, including a decrease of the most threatening perioperative complication of which is a transient or permanent worsening of the patient’s neurological condition. Aim of the study was the assessment of the frequency of microembolisation occurrence during carotid endarterectomy and the evaluation of other factors increasing the risk of the appearance of neurological deficits during or after a carotid endarterectomy procedure.
Material and methods: 76 patients operated on for carotid arteries atherosclerotic stenosis were enrolled into a clinical and ultrasonography evaluation and were divided into 2 groups: those with neurological deficit which occurred during or after the operation, 6 persons (7.8%), and those without neurological deficit, 70 patients (92.2%). The changes in the patients’ neurological condition, including the formation of neurological deficits, the decrease of blood flow velocity in the middle cerebral artery detected by transcranial doppler ultrasonography (TDU), and cerebral microembolism originating during four succeeding stages of the operation, were observed during the study.
Results: Embolisation was found in 71 patients (93%), while the average number of embolisations was greater in the group with neurological deficit (57.3) in comparison to the group without deficits (25.3) (p = 0.0001). In the group with neurological deficit, the mean decrease of blood flow velocity in the middle cerebral artery as a result of clamping amounted to 33.7 cm/sec (SD, standard deviation: 22.7, median: 31) compared with 16.3 cm/sec (SD: 14.8, median: 15) (p = 0.012) in the group without neurological deficit. In the group of patients with neurological deficit, carotid plaque ulceration was significantly more frequent in comparison to patients without neurological deficit, with 2 (33%) and 5 (7.1%) patients respectively (p = 0.01).
Conclusions: Microembolisation caused by platelet aggregates and the fragments of atherosclerotic plaque during surgical dissection is a common phenomenon during carotid endarterectomy. A logit analysis indicated that the decrease of average blood flow velocity, the presence of ulceration and a higher grade of the common carotid artery stenosis are the independent factors increasing the probability of neurological deficit appearance.