Cerebrovacular Reserve Predicts the Cerebral Hyperperfusion Syndrome After Carotid Endarterectomy.

BACKGROUND: Cerebral hyperperfusion syndrome is a rare but potentially severe complication of carotid artery revascularisation that develops under conditions of resistant postoperative hypertension and impaired cerebrovascular autoregulation. OBJECTIVE: Was to determine which preoperative and operative factors affect the development of cerebral hyperperfusion syndrome after carotid endarterectomy. METHODS: This prospective observational study enrolled 93 asymptomatic patients who underwent carotid endarterectomy. Cerebral hyperperfusion was registered in patients who had 100% postoperative increase in mean flow in middle cerebral artery registered by Transcranial Doppler ultrasound. Cerebral hyperperfusion syndrome was diagnosed in patients with cerebral hyperperfusion who postoperatively developed at least one of the symptoms. Pre-operative and operative risk factors for cerebral hyperperfusion syndrome were analysed by multivariate binary logistic regression. RESULTS: Out of 93 operated patients, cerebral hyperperfusion was registered in 23 and cerebral hyperperfusion syndrome in 18 patients. Risk factors for cerebral hyperperfusion syndrome were included in the binary logistic regression model. Incomplete Circle of Willis morphology on 3D TOF magnetic resonance image (p = 0.002), Breath holding index below the 0.69 cut-off (p = 0.006), positive criteria for insufficient collateral flow through circle of Willis registered by TCD (p = 0.03), and poorly controlled hypertension (p = 0.023) showed statistically significant independent predictive value for cerebral hyperperfusion syndrome. The model was statistically significant (p = 0.012) and correctly classified 90.3 % of patients. CONCLUSIONS: Incomplete circle of Willis and insufficient collateral flow, low cerebrovascular reserve, and poorly regulated hypertension are significant predictors of post- carotid endarterectomy hyperperfusion development.

COMPLETENESS OF CIRCLE OF WILLIS IN ASYMPTOMATIC AND SYMPTOMATIC EXTRACRANIAL CAROTID DISEASE.

INTRODUCTION: This research has been aimed at determining whether incomplete Circle of Willis in patients with significant extracranial carotid stenosis is associated with a higher incidence of neurological symptomatology and/or ischemnic cerebral lesions. MATERIAL AND METHODS: The research was conducted as a prospective study which comprised 211 patients who underwent surgical treatment of extracranial carotid disease at the Department of Vascular Surgery in Novi Sad and 102 patients in the control group. Each patient underwent preoperative magnetic resonance imaging and magnetic resonance angiography with visualization of cerebral parenchyma. extracranial and intracranial cerebral circulation. Assessment of Circle of Willis morphology was performed by 3D time-of-fight magnetic resonance angiogram sequence analysis. The patients were divided into two groups: group I - the patients with'complete Circle of Willis and group II - the patients with incomplete Circle of Willis i.e. with the disruption of anterior and/ or ipsilateral posterior circulation - regarding the side of signif icant carotid stenosis. RESULTS: Out of 211 patients who -were operated during a two-year period, 133 had the complete Circle of Willis. while 78 patients had the incomplete Circle of Willis. Out of 111 patients with symptomatic carotid disease or silent cerebral infarction, 52.5% (58) had the complete Circle of' Willis and 47.5% (53) had the incomplete Circle of Willis. It was shown to be statistically different (P = 0.0146) in relation with the asymptomatic group of patients (100), where the frequency of the complete Circle of Willis was 75% (75) while the insufficiency of anterior or ipsilateral posterior collateral ization was found in 25% (25). In the control group there were significantly fewer cases of developed collateral flow and the complete Circle of Willis (41%) compared to the operated patients with extracranial carotid stenosis (63%) (P= 0.0003). CONCLUSION: Incompleteness of Circle of Willis is associated with more frequent occurrence of neurological symptomatology or ischemic lesions of brain parenchyma in operated patients with significant extracranial carotid stenosis. The control group without extracranial carotid stenosis had less developed collaterals of Circle of Willis compared to extracranial carotid patients.