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.