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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WHAT THIS PAPER ADDSThis study investigated peri-operative blood pressure (BP) in patients undergoing carotid endarterectomy and its relationship with post-operative ischaemic brain lesions on magnetic resonance diffusion weighted imaging (DWI). There is increasing insight into the clinical relevance of DWI lesions, but little is known about the predictive, causative factors. This is the first study into the relationship between new DWI lesions (ipsi-or contralateral) and pre-operative vs. intra-operative BP. The results imply that patients with pre-operative hypertension are susceptible to intra-operative haemodynamic instability and development of silent DWI lesions. These data may affect future protocols for peri-operative haemodynamic regulation.Objective: Intra-operative haemodynamic instability during carotid endarterectomy (CEA) has been associated with an increased risk of procedural stroke. Diffusion weighted imaging (DWI) lesions have been proposed as a surrogate marker for peri-operative silent cerebral ischaemia. This study aimed to investigate the relationship between peri-operative blood pressure (BP) and presence of post-operative DWI lesions in patients undergoing CEA. Methods: A retrospective analysis was performed based on patients with symptomatic CEA included in the MRI substudy of the International Carotid Stenting Study. Relative intra-operative hypotension was defined as a decrease of intra-operative systolic BP ! 20% compared with pre-operative ('baseline') BP, absolute hypotension was defined as a drop in systolic BP < 80 mmHg. The primary endpoint was the presence of any new DWI lesions on postoperative MRI (DWI positive). The occurrence and duration of intra-operative hypotension was compared between DWI positive and DWI negative patients as was the magnitude of the difference between pre-and intra-operative BP. Results: Fifty-five patients with symptomatic CEA were included, of whom eight were DWI positive. DWI positive patients had a significantly higher baseline systolic (186 AE 31 vs. 158 AE 27 mmHg, p ¼ .011) and diastolic BP (95 AE 15 vs. 84 AE 13 mmHg, p ¼ .046) compared with DWI negative patients. Other pre-operative characteristics did not differ. Relative intra-operative hypotension compared with baseline occurred in 53/55 patients (median duration 34 min; range 0e174). Duration of hypotension did not differ significantly between the groups (p ¼ .088). Mean systolic intra-operative BP compared with baseline revealed a larger drop in BP (À37 AE 29 mmHg) in DWI positive compared with DWI negative patients (À14 AE 26 mmHg, p ¼ .024). Absolute intra-operative systolic BP values did not differ between the groups. Conclusion: In this exploratory study, high pre-operative BP and a larger drop of intra-operative BP were associated with peri-procedural cerebral ischaemia as documented with DWI. These results call for confirmation in an adequately sized prospective study, as they suggest important consequences for perioperative haemodynamic management in carotid revascularisation.

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.

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Guidance on peri-operative haemodynamics is crucial to prevent procedural stroke in carotid endarterectomy (CEA) by preserving cerebral perfusion. 1,2 Newman et al. suggest a one size fits all post-operative systolic blood pressure (BP) policy treating > 170 mmHg or > 160 mmHg in patients with symptoms. 3 This policy causes significant overtreatment, as two in five CEA patients will undergo in hospital BP lowering treatment for several days, leading to a high workload, increased in hospital costs, and bed occupancy. In reality, only a subset of patients truly need immediate strict BP lowering therapy to prevent cerebral hyperperfusion syndrome (CHS), which occurs in 3e5% of CEA patients. 4 Peri-operative transcranial Doppler (TCD) can identify patients at risk of CHS. Owing to the high negative predictive value of 99% no patient needing strict BP therapy will be left untreated. 4 With TCD, only one in 10 patients requires immediate and strict BP lowering on a medium care unit, thereby avoiding significant overtreatment, as the remaining 90% of patients (even when BP exceeds 170 mmHg in the absence of symptoms) can be discharged safely and have elective BP lowering intervention via the outpatient clinic. Of note, Newman's protocol can never prevent all CHS cases, as CHS may also occur with stable systolic BP as low as 130 mmHg! 4 Post-CEA hypertension (PEH) is a risk factor for CHS and intracranial haemorrhage. However, these complications are not reported as outcome parameters. From the perspective of the very small sample size, the clinical implications of the proposed one size fits all treatment approach for PEH, to direct peri-operative haemodynamic therapy remain unclear. Of note, achievement of immediate and persisting BP lowering in cardiovascularly compromised patients can be very challenging! Instead, we propose a tailored approach using TCD to identify all patients that are at true high risk of PEH related complications following CEA.