Predictors of cross-clamp-induced intraoperative monitoring changes during carotid endarterectomy using both electroencephalography and somatosensory evoked potentials

Changes in Neonatal Intraoperative Electroencephalogram Alpha: Delta Ratios Precede Neurologic Injury

Background: Unrecognized intraoperative cerebral ischemia during neonatal aortic arch reconstruction may precede neurologic injury. Electroencephalogram (EEG) alpha:delta ratio (A:D) changes predict cerebral ischemia; however, if A:D differences can identify ischemia during neonatal antegrade cerebral perfusion (ACP) and aortic arch reconstruction is unknown. We hypothesized that A:D changes would precede neurologic injury. Methods: Simultaneous EEG derived left versus right: hemispheric and anterior cerebral A:Ds were retrospectively measured at baseline and every 5 min during arterial cannulation, cooling, ACP, and the rewarming phases of the operation. A paired left versus right A:D difference >25% was considered significant for ischemia, and the duration of a significant and continuous A:D difference was quantified in minutes. Neonates were divided into two groups: (1) new neurologic injury (stroke or seizure) and (2) no known neurologic injury. Results: From 72 neonates, there were no significant differences in the baseline A:Ds. Seven neonates (9.7%) developed a new neurologic injury (seizure = 3, stroke = 2, seizure and stroke = 2). Male gender and longer ACP times were significantly associated with neurologic injury. In neonates with a neurologic injury, the duration of a significant and continuous A:D difference was longer within the hemispheric and anterior regions. Multivariable analysis demonstrated that a significant and continuous anterior A:D difference (odds ratio: 1.345, 95% CI 1.058-1.712; P = .01) was independently associated with neurologic injury. Conclusions: A longer continuous anterior A:D difference > 25% was independently associated with neurologic injury. Intraoperative EEG monitoring could be considered during neonatal arch reconstruction.

Safety of Shunting Strategies During Carotid Endarterectomy: A Vascular Quality Initiative Data Analysis

OBJECTIVE

This study aimed to evaluate in hospital outcomes after carotid endarterectomy (CEA) according to shunt usage, particularly in patients with contralateral carotid occlusion (CCO) or recent stroke. Data from CEAs registered in the Vascular Quality Initiative database between 2012 and 2020 were analysed, excluding surgeons with < 10 CEAs registered in the database, concomitant procedures, re-interventions, and incomplete data.

METHODS

Based on their rate of shunt use, participating surgeons were divided in three groups: non-shunters (< 5%), selective shunters (5 - 95%), and routine shunters (> 95%). Primary outcomes of in hospital stroke, death, and stroke and death rate (SDR) were analysed in symptomatic and asymptomatic patients.

RESULTS

A total of 113 202 patients met the study criteria, of whom 31 147 were symptomatic and 82 055 were asymptomatic. Of the 1 645 surgeons included, 12.1% were non-shunters, 63.6% were selective shunters, and 24.3% were routine shunters, with 10 557, 71 160, and 31 579 procedures in each group, respectively. In the univariable analysis, in hospital stroke (2.0% vs. 1.9% vs. 1.6%; p = .17), death (0.5% vs. 0.4% vs. 0.4%; p = .71), and SDR (2.2% vs. 2.1% vs. 1.8%; p = .23) were not statistically significantly different among the three groups in the symptomatic cohort. The asymptomatic cohort also did not show a statistically significant difference for in hospital stroke (0.9% vs. 1.0% vs. 0.9%; p = .55), death (0.2% vs. 0.2% vs. 0.2%; p = .64), and SDR (1.0% vs. 1.1% vs. 1.0%; p = .43). The multivariable model did not show a statistically significant difference for the primary outcomes between the three shunting cohorts. On subgroup analysis, the SDRs were not statistically significantly different for patients with CCO (3.3% vs. 2.5% vs. 2.4%; p = .64) and those presenting with a recent stroke (2.9% vs. 3.4% vs. 3.1%; p = .60).

CONCLUSION

No statistically significant differences were found between three shunting strategies for in hospital SDR, including in patients with CCO or recent stroke.

Diagnostic accuracy of intraoperative neuromonitoring in transcarotid artery revascularization

BACKGROUND

In recent years, transcarotid artery revascularization (TCAR) has emerged as a safe and effective alternative to carotid artery stenting. While intraoperative neuromonitoring (IONM) techniques such as electroencephalogram (EEG) and somatosensory evoked potentials (SSEPs) are often employed during TCAR, there is limited research on their diagnostic accuracy.

METHODS

The authors retrospectively reviewed a multi-institutional IONM database of TCAR procedures performed with EEG and SSEP monitoring. A total of 516 TCAR procedures were included in this study. Significant changes in EEG and/or SSEPs, surgeon's interventions, resolution of significant changes, and immediate postoperative neurological outcome were documented. Sensitivity, specificity, positive and negative predictive values were calculated.

RESULTS

The incidence of intraoperative onset new neurologic deficit was 0.4%. Significant changes in EEG and/or SSEPs occurred in 5.4% of the cases. Of the cases with IONM alerts, 78.5% returned to baseline with a surgical or hemodynamic intervention. From the cases with unresolved IONM alerts, 33.3% woke up with a new neurological deficit. The overall sensitivity and specificity for IONM was 100% and 99.2%, respectively. The positive predictive value was 33.3% and the negative predictive value was 100%.

CONCLUSIONS

IONM during TCAR offers high sensitivity and specificity in predicting postoperative outcome. Patients with resolved IONM alerts had immediate neurological outcomes that were comparable to those who had no IONM alerts.

Thrombosis or vasospasm: The utility of intraoperative neuromonitoring during TCAR

OBJECTIVES

Transcarotid artery revascularization (TCAR) has become more prevalent as a treatment modality for carotid stenosis. Many centers perform TCAR without any adjunctive neuromonitoring, for example, somatosensory-evoked potential (SSEP) and electroencephalogram (EEG).

METHODS

We present a case of transcarotid artery revascularization (TCAR) performed with concomitant somatosensory-evoked potential (SSEP) and electroencephalogram (EEG) neuromonitoring in the setting of concerning intraoperative angiographic images.

RESULTS

TCAR was undertaken for a 58 year-old man presenting with symptomatic left carotid stenosis and right ICA occlusion. Based on his comorbidities, pre-existing conditions, and the need for dual antiplatelet therapy, TCAR was offered as an alternative to standard carotid endarterectomy. Intraoperatively, following stent delivery, no flow was appreciated through the carotid stent or distal ICA. Neuromonitoring remained stable and was reassuring for distal ICA spasm with no-reflow phenomenon. The patient tolerated the procedure well and has had no stent-related complications through 10 months of follow-up.

CONCLUSION

This case highlights the utility of neuromonitoring with TCAR as an adjunct to intraoperative decision-making in the setting of suspected internal carotid artery (ICA) vasospasm versus thrombosis after stent delivery.

Prediction of cerebral perfusion pressure during carotid surgery - A computational fluid dynamics approach

BACKGROUND

Maintaining cerebral perfusion pressure in the brain when a carotid artery is closed during vascular surgery is critical for avoiding intraoperative hypoperfusion and risk of ischemic stroke. Here we propose and evaluate a method based on computational fluid dynamics for predicting patient-specific cerebral perfusion pressures at carotid clamping during carotid endarterectomy.

METHODS

The study consisted of 22 patients with symptomatic carotid stenosis who underwent carotid endarterectomy (73 ± 5 years, 59-80 years, 17 men). The geometry of the circle of Willis was obtained preoperatively from computed tomography angiography and corresponding flow rates from four-dimensional flow magnetic resonance imaging. The patients were also classified as having a present or absent ipsilateral posterior communicating artery based on computed tomography angiography. The predicted mean stump pressures from computational fluid dynamics were compared with intraoperatively measured stump pressures from carotid endarterectomy.

FINDINGS

On group level, there was no difference between the predicted and measured stump pressures (-0.5 ± 13 mmHg, P = 0.86) and the pressures were correlated (r = 0.44, P = 0.039). Omitting two outliers, the correlation increased to r = 0.78 (P < 0.001) (-1.4 ± 8.0 mmHg, P = 0.45). Patients with a present ipsilateral posterior communicating artery (n = 8) had a higher measured stump pressure than those with an absent artery (n = 12) (P < 0.001).

INTERPRETATION

The stump pressure agreement indicates that the computational fluid dynamics approach was promising in predicting cerebral perfusion pressures during carotid clamping, which may prove useful in the preoperative planning of vascular interventions.

Carotid Endarterectomy Surgeries: A Multimodality Intraoperative Neurophysiological Monitoring Approach

Patients with untreated carotid artery stenosis remain at high risk for stroke. Carotid endarterectomy (CEA) is a surgical procedure for the treatment of symptomatic and severe asymptomatic carotid stenosis. A small percentage of patients who do not have good collateral circulation are at high risk of cerebral ischemia during the cross-clamping of the carotid artery. Aspects of CEA, such as cross-clamping and routine shunting, can also carry the risk of perioperative stroke through dislodgement of emboli causing thrombosis, therefore, selective shunting is highly recommended during the CEA procedure. A multimodality approach of intraoperative neurophysiological monitoring (IONM) techniques such as somatosensory evoked potential (SSEP) and electroencephalography (EEG) can be used to monitor cerebral perfusion throughout the duration of the surgery and to predict the need for a selective shunt after cross-clamping. Additional use of transcranial Doppler (TCD) in the multimodality approach can aid in visualizing the cerebral blood flow and detecting any microemboli that may also cause a stroke. A multimodality IONM approach has been reported as more sensitive and specific for predicting and minimizing any postoperative neurological deficits.

Prediction of cross-clamp-induced cerebral ischemia during carotid endarterectomy using arterial blood flow assessment

BACKGROUND

Cross-clamping during carotid endarterectomy (CEA) is associated with the risk of cerebral ischemia. Various studies have evaluated different criteria for detecting cerebral ischemia, but difficulties arise when ischemic changes appear after the carotid artery is cross-clamped and incised. Here, we explored a parameter that can predict cerebral ischemia prior to cross-clamping during CEA using a blood-flow meter.

METHODS

The carotid arterial blood flow was measured directly (direct ABF) in the common carotid artery prior to cross-clamping. The anatomical information in preoperative magnetic resonance imaging, cerebral blood flow in xenon-enhanced computed tomography, and carotid peak systolic flow velocity by carotid echo from the skin surface were also evaluated. A decrease in the short-latency somatosensory evoked potentials (SSEP) during cross-clamping to insert a shunt was assessed, and a decrease in amplitude of ≥50% was considered an indicator for cerebral ischemia. Surgery was performed under general anesthesia, and a shunt was inserted in all cases.

RESULTS

Of 156 CEA patients between April 2013 and March 2020, 30 had decreased SSEP during cross-clamping. The baseline characteristics and intra- and postoperative findings were not significantly different between patients with and without a decrease in SSEP. Among the evaluated parameters, only the direct-ABF ratio (ABF-internal carotid artery/ABF-common carotid artery) differed significantly between the two groups (p=0.011). The direct-ABF ratio ≤0.58 was predictive of cerebral ischemia during CEA.

CONCLUSIONS

Direct-ABF measurement with an ultrasonic blood-flow meter can be useful for predicting cerebral ischemia prior to carotid artery cross-clamping during CEA.

Management of neurophysiological monitoring changes during carotid endarterectomy exposure

BACKGROUND

Carotid endarterectomy (CEA) is a safe and effective operation in the management of carotid stenosis. Intraoperative neurophysiologic monitoring (IONM) changes during carotid clamping has been well studied, but there is scant evidence detailing IONM changes during carotid exposure.

OBJECTIVE

We analyzed our experience with IONM changes during CEA exposure to determine whether multimodal IONM changes during exposure predict outcomes and how best to manage this challenging clinical scenario.

METHODS

We reviewed all CEAs performed at our medical center between January 2015 and June 2020 and identified patients with multimodal IONM changes during exposure of the carotid artery. Our primary outcomes were perioperative stroke and functional outcomes. Functional outcomes were measured by modified Rankin scale (mRS), with good functional outcome defined at mRS scores 0-3. We also reviewed our intraoperative IONM change management strategies.

RESULTS

Five patients (4 males, 1 female) with an average age of 67 ± 12 years had intraoperative IONM changes during carotid exposure. Among these, three patients were discharged with good functional outcome, and four patients had a good functional outcome at last follow-up. Two patients had perioperative stroke, half of which resulted in significant disability. One patient was transferred to the neuroendovascular suite intraoperatively for evaluation for thromboembolism followed by angioplasty and stenting with distal protection.

CONCLUSION

Intraoperative IONM changes during carotid exposure predict outcomes in CEA. We propose that transition to the neuroendovascular suite following significant IONM changes during carotid exposure may be a useful strategy for management of this challenging clinical scenario. This approach provides the opportunity to evaluate and treat thromboembolism and still complete carotid revascularization when appropriate. This algorithm may be particularly useful in the era of dual trained vascular neurosurgeons.

Role of Doppler Ultrasound Analysis of Blood Flow Through the Ophthalmic and Intracranial Arteries in Predicting Neurologic Symptoms During Carotid Endarterectomy

OBJECTIVES

Carotid endarterectomy (CEA) is frequently performed under locoregional anesthesia. The intraoperative clamping of the internal carotid artery (ICA) leads to cerebral hypoperfusion, which may in some patients result in the development of neurologic symptoms (NS). The objective of our study was to investigate whether there is an association between the preoperative ultrasound (US) Doppler flow in the ophthalmic artery (OA) and intracranial artery and the occurrence of these intraoperative NS.

METHODS

We compared 50 patients with NS and 150 patients without NS during CEA. We analyzed their preoperative blood flow characteristics by Doppler US and their clinical and demographic characteristics.

RESULTS

The contralateral ICA occlusion increased the likelihood of intraoperative NS (odds ratio [OR], 8.4; P < .001). Abnormal contralateral OA flow also increased the likelihood of NS (OR, 1.84; P < .001), whereas ipsilateral abnormal OA flow reduced it (OR, 0.73; P = .06). Increased flow in the ipsilateral anterior cerebral artery (ACA) increased the likelihood of NS (OR, 3.3), whereas reversed flow decreased it (OR, 0.1; P = .03). Inverse flow in the contralateral ACA increased the risk (OR, 5.4), whereas increased flow reduced it (OR, 0.2; P = .02). Male patients had a higher risk of NS (P = .09) as well as older patients (P = .05). Eight percent of the patients with NS developed a transient ischemic attack or stroke.

CONCLUSIONS

Doppler US analysis of the OA and ACA in combination with analysis of ICA stenosis may be a promising predictor of NS during ICA clamping. This, in turn, may warn the patient and the surgeon of an increased risk during surgery.

Selective internal carotid artery cross-clamping increases the specificity of cerebral oximetry for indication of shunting during carotid endarterectomy

BACKGROUND

An indication for selective shunting during carotid endarterectomy (CEA) is based on monitoring during a procedure. Cerebral oximetry (CO) using near-infrared spectroscopy (NIRS) may be a simple technique, but its relevance during CEA, especially with respect to cutoff values indicating shunt implantation, still needs to be elucidated.

METHODS

One hundred twenty five patients underwent CEA under local anesthesia (LA) and were monitored clinically throughout the whole procedure. The patients were also monitored using bilateral NIRS probes during surgery. The NIRS values were recorded and evaluated before and after selective cross-clamping, firstly by the external carotid artery (ECA), followed by the internal carotid artery (ICA). The decrease in the ipsilateral CO values, with respect to the indication of shunting, was only analyzed after selective cross-clamping of the ICA. The decision to use an intraluminal shunt was solely based on the neurological status evaluation after ICA cross-clamping.

RESULTS

One hundred five patients (85%) were stable throughout the CEA, while 20 patients (15%) clinically deteriorated during surgery. The mean drop in the CO after selective ICA clamping in clinically stable patients was 6%, while in patients with clinical deterioration, the NIRS decreased by 14.5% (p < 0.05). When the cutoff value for selective shunting was set as a 10% decrease of the ipsilateral CO after selective ICA clamping, the sensitivity of the technique was 100% and the specificity 83.0%.

CONCLUSIONS

Our study showed that a 10% decrease in the ipsilateral brain tissue oximetry after selective cross-clamping the ICA provides a reliable cutoff value for selective shunting during CEA. Despite the availability of a variety of monitoring tools, the NIRS may be an easy, reliable option, especially in the scenario of acute CEA in general anesthesia.

Quantitative EEG Changes Correlate With Post-Clamp Ischemia During Carotid Endarterectomy

INTRODUCTION

EEG monitoring is a critical tool for identifying cerebral ischemia during carotid endarterectomy (CEA). Quantitative EEG can be used to supplement visual EEG review, but which measures best predict post-clamp ischemia is unclear.

PURPOSE

To determine which quantitative EEG parameters reliably detect intraoperative ischemia during CEA.

METHODS

The authors identified patients who underwent carotid endarterectomy at Columbia University Medical Center from 2007 to 2014 with intraoperative EEG monitoring. Two masked physicians reviewed these EEGs retrospectively and determined whether there was post-clamp ischemia, categorizing patients into (1) ischemic-change and (2) no-ischemic-change groups. The authors then studied the performance of a battery of quantitative EEG measures (alpha, beta, theta, and delta power bands, alpha-delta ratio, beta-delta ratio, amplitude-integrated EEG, and 90% spectral edge frequency) against physician review as the gold standard.

RESULTS

Of 118 patients, 15 were included in the ischemic-change group and 103 in the no-ischemic-change group. Ipsilateral post-clamp trough values of all the quantitative EEG measures assessed were significantly decreased for patients in the ischemic-change group. Decreases in alpha, beta, and theta power of 52.1%, 41.6%, and 36.4% or greater, respectively, were most predictive of post-clamp ischemia.

CONCLUSIONS

Quantitative EEG monitoring during carotid endarterectomy, in addition to visual EEG monitoring, may improve the detection of cerebral ischemia and thus result in fewer perioperative strokes.

Stroke Rates Following Surgical Versus Percutaneous Revascularization for Ischemic Heart Disease

PURPOSE OF REVIEW

Coronary revascularization is a commonly performed major procedure in the hospitals. Stroke is one of the dreaded complications after coronary revascularization procedures. The focus of this review is to understand the stroke risk in percutaneous cutaneous intervention (PCI) and coronary artery bypass grafting (CABG) procedures.

RECENT FINDINGS

Available data show that PCI offers less procedural stroke risk compared to CABG although the survival benefits of CABG are better in certain scenarios. Innovative advancements in techniques, pre-procedural optimum medical therapy (OMT), intraoperative neuro-monitoring, and multidisciplinary post procedural care are the few strategies in early detection and reduce stroke risk. Despite several innovations and strategies, it is evident that there is not enough data available to make concrete conclusions related to stroke risk after coronary revascularization, which warrants further investigation.

The Anatomy of the Circle of Willis Is Not a Strong Enough Predictive Factor for the Prognosis of Cross-Clamping Intolerance during Carotid Endarterectomy

Carotid endarterectomy (CEA) is safe and effective in reducing the risk of stroke in symptomatic severe carotid artery stenosis. Having information about cross-clamping (CC) intolerance before surgery may reduce the complication rate. The purpose of this study was to assess the usefulness of magnetic resonance angiography (MRA) and magnetic resonance angiography perfusion (P-MR) in determining the risk of CC intolerance during CEA. Material and methods: 40 patients after CEA with CC intolerance were included in Group I, and 15 with CC tolerance in Group II. All patients underwent MRA of the circle of Willis (CoW), P-MR with or without Acetazolamide; P(A)-MR in the postoperative period. Results: CoW was normal in the MRA in three cases (7.5%) in Group I, and in eight (53%) in Group II. We found P-MR abnormalities in all patients from Group I and in 40% from Group II. Using a calculated cut-off point of 0.322, the patients were classified as CC tolerant with 100% sensitivity or as CC intolerant with 95% specificity. After evaluating P-MR or MRA alone, the percentage of false negative results significantly increased. Conclusion: The highest value in predicting cross-clamping intolerance is achieved by using analysis of P(A)-MR and MRA of the CoW in combination.

Loss of Motor Evoked Potentials Due to Carotid Artery Retraction in an Exoscopic Clipping of a Basilar Tip Aneurysm

The internal carotid artery (ICA) may inhibit visualization of a basilar tip aneurysm during an orbitozygomatic craniotomy. Retraction of the ICA may be warranted for better visualization; however, it may lead to impending neurological sequelae. Impending neurological injury due to ICA retraction may be mitigated if multi-modal neuromonitoring techniques are employed. The authors present a case report showing the contemporaneous loss of transcranial motor evoked potentials and direct cortical motor evoked potentials during an exoscopic clipping of a basilar tip aneurysm due to ICA retraction and subsequent loss of perfusion to the vascular territory supplied by ICA. The motor evoked potentials immediately returned after retraction was removed and the patient awoke neurologically intact.

Last Electrically Well: Intraoperative Neurophysiological Monitoring for Identification and Triage of Large Vessel Occlusions

INTRODUCTION

Intra-operative stroke (IOS) is associated with poor clinical outcome as detection is often delayed and time of symptom onset or patient's last known well (LKW) is uncertain. Intra-operative neurophysiological monitoring (IONM) is uniquely capable of detecting onset of neurological dysfunction in anesthetized patients, thereby precisely defining time last electrically well (LEW). This novel parameter may aid in the detection of large vessel occlusion (LVO) and prompt treatment with endovascular thrombectomy (EVT).

METHODS

We performed a retrospective analysis of a prospectively maintained AIS and LVO database from May 2018-August 2019. Inclusion criteria required any surgical procedure under general anesthesia (GA) utilizing EEG (electroencephalography) and/or SSEP (somatosensory evoked potentials) monitoring with development of intraoperative focal persistent changes using predefined alarm criteria and who were considered for EVT.

RESULT

Five cases were identified. LKW to closure time ranged from 66 to 321 minutes, while LEW to closure time ranged from 43 to 174 min. All LVOs were in the anterior circulation. Angiography was not pursued in two cases due to large established infarct (both patients expired in the hospital). EVT was pursued in two cases with successful recanalization and spontaneous recanalization was noted in one patient (mRS 0-3 at 90 days was achieved in all 3 cases).

CONCLUSIONS

This study demonstrates that significant IONM changes can accurately identify patients with an acute LVO in the operative setting. Given the challenges of recognizing peri-operative stroke, LEW may be an appropriate surrogate to quickly identify and treat IOS.

Shunt intention during carotid endarterectomy in the early symptomatic period and perioperative stroke risk

OBJECTIVE

Whether recent stroke mandates planned shunting during carotid endarterectomy (CEA) is controversial. Our goal was to determine associations of various shunting practices with postoperative outcomes of CEAs performed after acute stroke.

METHODS

The Vascular Quality Initiative database (2010-2018) was queried for CEAs performed within 14 days of an ipsilateral stroke. Surgeons who prospectively planned to shunt either shunted routinely per their usual practice or shunted selectively for preoperative indications. Surgeons who prospectively planned not to shunt either shunted selectively for intraoperative indications or did not shunt. Univariable and multivariable analyses compared shunting approaches.

RESULTS

There were 5683 CEAs performed after acute ipsilateral stroke. Surgeons planned to shunt in 56.1% of cases. Patients whose surgeons planned to shunt vs planned not to shunt were more likely to have severe contralateral stenosis (8.8% vs 6.9%; P = .008), to receive general anesthesia (97.5% vs 89.1%; P < .001), and to undergo conventional CEA (94% vs 81.8%; P < .001). Unadjusted outcomes were similar between the cohorts for operative duration (124.3 ± 48.1 minutes vs 123.6 ± 47 minutes; P = .572) and 30-day stroke (3.4% vs 3%; P = .457), myocardial infarction (1.1% vs 0.8%; P = .16), and mortality (1.6% vs 1.3%; P = .28). On multivariable analysis, planning to shunt vs planning not to shunt was associated with similar risk of 30-day stroke (odds ratio [OR], 1.17; 95% confidence interval [CI], 0.82-1.67; P = .402). On subgroup analysis, in 38.4% patients, no shunt was placed, whereas the remainder received routine shunts (44.4%), preoperatively indicated shunts (11.6%), and intraoperatively indicated shunts (5.5%). Compared with no shunting, shunting by surgeons who routinely shunt was associated with a similar stroke risk (OR, 1.39; 95% CI, 0.91-2.13; P = .129), but shunting by surgeons who selectively shunt on the basis of preoperative indications (OR, 2.11; 95% CI, 1.22-3.63; P = .007) or intraoperative indications (OR, 3.34; 95% CI, 1.86-6.01; P < .001) was associated with increased stroke risk. Prior coronary revascularization independently predicted increased intraoperatively indicated shunting (OR, 1.37; 95% CI, 1.05-1.8; P = .022).

CONCLUSIONS

In CEAs performed after acute ipsilateral stroke, there is no difference in postoperative stroke risk when surgeons prospectively plan to shunt or not to shunt. Shunting is often not necessary; however, when shunting is performed, routine shunters achieve better outcomes.

The utility of adjunctive electroencephalography while performing transcarotid artery revascularization

Transcarotid artery revascularization (TCAR) has been used as an alternative to carotid endarterectomy and transfemoral carotid artery stenting. Although TCAR has been associated with a decrease in perioperative strokes compared with transfemoral carotid artery stenting, little is known about the safety of cerebral blood during flow reversal or the value of adjunctive electroencephalography (EEG) monitoring in performing TCAR. We describe two cases of EEG changes in patients undergoing TCAR. These cases highlight the use of adjunctive EEG and provide examples of test clamping to assess for compromised collateral cerebral blood flow in patients undergoing TCAR.