WHAT THIS PAPER ADDSA validated prediction model for prevention of cerebral hyperperfusion syndrome (CHS) following carotid endarterectomy (CEA) is lacking; however, early recognition of cerebral hyperperfusion (CH) is crucial to prevent this complication. Intra-operative transcranial Doppler (TCD) is the gold standard to predict the risk of CH in CEA patients under general anaesthesia, but this study finds that post-operative TCD 24 h after CEA is more effective at predicting CH and CHS and is excellent at identifying patients NOT at risk of CHS after CEA. This has clinical relevance for cerebral monitoring protocols in centres performing CEA under general anaesthesia.Objectives: Intra-operative transcranial Doppler (TCD) is the gold standard for prediction of cerebral hyperperfusion syndrome (CHS) in patients after carotid endarterectomy (CEA) under general anaesthesia. However, post-operative cerebral perfusion patterns may result in a shift in risk assessment for CHS. This is a study of the predictive value of additional post-operative TCD measurements for prediction of CHS after CEA. Methods: This was a retrospective analysis of prospectively collected data in patients undergoing CEA with available intra-and post-operative TCD measurements between 2011 and 2016. The mean blood flow velocity in the middle cerebral artery (MCAV mean ) was measured pre-operatively, intra-operatively, and postoperatively at two and 24 h. Intra-operative MCAV mean increase was compared with MCAV mean increase two and 24 h post-operatively in relation to CHS. Cerebral hyperperfusion (CH) was defined as MCAV mean increase ! 100%, and CHS as CH with the presence of headache or neurological symptoms. Positive (PPV) and negative predictive values (NPV) of TCD measurements were calculated to predict CHS. Results: Of 257 CEA patients, 25 (9.7%) had CH intra-operatively, 45 (17.5%) 2 h post-operatively, and 34 (13.2%) 24 h post-operatively. Of nine patients (3.5%) who developed CHS, intra-operative CH was diagnosed in two and post-operative CH in eight (after 2 h [n ¼ 5] or after 24 h [n ¼ 6]). This resulted in a PPV of 8%, 11%, and 18%, and a NPV of 97%, 98%, and 99% for intra-operative, 2 h and 24 h post-operative TCD, respectively. Conclusions: TCD measurement of the MCAV mean 24 h after CEA under general anaesthesia is most accurate to identify patients who are not at risk of CHS.

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BackgroundShort-acting vasopressor agents like phenylephrine or ephedrine can be used during carotid endarterectomy (CEA) to achieve adequate blood pressure (BP) to prevent periprocedural stroke by preserving the cerebral perfusion. Previous studies in healthy subjects showed that these vasopressors also affected the frontal lobe cerebral tissue oxygenation (rSO2) with a decrease after administration of phenylephrine. This decrease is unwarranted in patients with jeopardized cerebral perfusion, like CEA patients. The study aimed to evaluate the impact of both phenylephrine and ephedrine on the rSO2 during CEA.MethodsIn this double-blinded randomized controlled trial, 29 patients with symptomatic carotid artery stenosis underwent CEA under volatile general anesthesia in a tertiary referral medical center. Patients were preoperative allocated randomly (1:1) for receiving either phenylephrine (50 µg; n = 14) or ephedrine (5 mg; n = 15) in case intraoperative hypotension occurred, defined as a decreased mean arterial pressure (MAP) ≥ 20% compared to (awake) baseline. Intraoperative MAP was measured by an intra-arterial cannula placed in the radial artery. After administration, the MAP, cardiac output (CO), heart rate (HR), stroke volume, and rSO2 both ipsilateral and contralateral were measured. The timeframe for data analysis was 120 s before, until 600 s after administration.ResultsBoth phenylephrine (70 ± 9 to 101 ± 22 mmHg; p < 0.001; mean ± SD) and ephedrine (75 ± 11 mmHg to 122 ± 22 mmHg; p < 0.001) adequately restored MAP. After administration, HR did not change significantly over time, and CO increased 19% for both phenylephrine and ephedrine. rSO2 ipsilateral and contralateral did not change significantly after administration at 300 and 600 s for either phenylephrine or ephedrine (phenylephrine 73%, 73%, 73% and 73%, 73%, 74%; ephedrine 72%, 73%, 73% and 75%, 74%, 74%).ConclusionsWithin this randomized prospective study, MAP correction by either phenylephrine or ephedrine showed to be equally effective in maintaining rSO2 in patients who underwent CEA.Clinical Trial Registration ClincalTrials.gov, NCT01451294.