Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting)

The intracranial effects of flow reversal during transcarotid artery revascularization

Background

This study aimed to assess intraoperative cerebral hemodynamic responses and embolic events during transcarotid artery revascularization via transcranial Doppler, near-infrared spectroscopy, and bispectral index monitoring.

Methods

Twelve patients (7 males, 5 females; mean age: 72.8±9.0 years; range, 63 to 91 years) undergoing transcarotid artery revascularization with simultaneous transcranial Doppler, near-infrared spectroscopy, and bispectral index monitoring were analyzed in this retrospective study between September 2017 and December 2019. The mean flow velocity and pulsatility index of the middle cerebral artery, alongside near-infrared spectroscopy and bispectral index values, before flow reversal, during flow reversal, and after flow reversal phases were investigated. The presence and frequency of high-intensity transient signals were recorded to evaluate embolic incidents.

Results

Significant reductions in middle cerebral artery mean flow velocity were noted during flow reversal (40.58±10.57 cm/sec to 20.58±14.34 cm/sec, p=0.0004), which subsequently returned to and exceeded baseline values after flow reversal cessation (53.33±17.69 cm/sec, p=0.0005). Near-infrared spectroscopy (71±4.4% to 66±6.2%) and bispectral index (45.71±8.5 to 40.14±8.1) values mirrored these hemodynamic changes, with notable decreases during flow reversal, and recoveries after flow reversal. The highest concentration of high-intensity transient signals was observed during stent deployment, signifying a critical embolic phase. No perioperative neurological complications or other significant adverse events were documented.

Conclusion

Transcranial Doppler, near-infrared spectroscopy, and bispectral index effectively monitor cerebral hemodynamics and embolic potential during transcarotid artery revascularization, providing real-time data crucial for optimizing perioperative management. These findings underscore the clinical value of multimodal monitoring in improving patient outcomes in transcarotid artery revascularization procedures.

Routine versus selective near-infrared spectroscopy-guided shunting during carotid eversion endarterectomy

OBJECTIVES

The aim of this study was to compare outcomes of routine shunting to near-infrared spectroscopy (NIRS)-guided shunting in patients undergoing eversion endarterectomy (EEA) under general anaesthesia.

METHODS

We retrospectively evaluated data of all patients undergoing EEA of the internal carotid artery (ICA) in our department from January 2011 until January 2019. Included were patients with EEA of the ICA and the patients were divided into 2 groups: selective-shunting group and routine-shunting group. Patients (i) with patch angioplasty during the surgery, (ii) undergoing surgery for restenosis and (ii) stenosis after radiation therapy, (iii) without recorded regional cerebral oxygen saturation trends, (iv) presenting with an emergency treatment indication and (v) operated upon by residents were excluded. In all patients, EEA was performed in general anaesthesia and under NIRS monitoring. One-to-one propensity score matching was used to compare EEA outcomes after routine shunting to NIRS-guided shunting. Primary end points were defined as perioperative stroke and in-hospital mortality after EEA.

RESULTS

Routine and NIRS-guided selective shunting were applied in 340 (34.0%) and 661 (66.0%) patients, respectively. A total of 277 pairs were generated via propensity score matching. Fifty-eight (20.1%) from the selective-shunting group were intraoperatively shunted. Concomitant procedures were more frequently performed in the routine-shunting group [170 (61.4%) vs 47 (17.0%), 180 (65%) vs 101 (36.5%), and 60 (21.7%) vs 6 (2.2%), P < 0.001]. The perioperative stroke rate in the routine-shunting group was higher as well [11 (4.0%) vs 3 (1.1%), P = 0.022]. In-hospital death was overall 0.2% (n = 1). Multivariable logistic regression in the matched patient indicated age (odds ratio 1.050, 95% confidence interval 1.002-1.104, P = 0.046) and routine shunting (odds ratio 2.788, confidence interval 1.119-7.428, P = 0.032) as risk factors for perioperative stroke during EEA of the ICA.

CONCLUSIONS

We found that, during EEA of the ICA, under general anaesthesia, NIRS-guided selective shunting was associated with a lower incidence of perioperative stroke than routine shunting.

Incomplete circle of Willis as a risk factor for intraoperative ischemic events during carotid endarterectomies performed under regional anesthesia - A prospective case-series

Background

The role of the willisian collaterals during carotid endarterectomies (CEAs) is a debated issue. The aim of the present work was to test whether an incomplete or non-functional circle of Willis (CoW) is a risk factor for ischemic events during CEA.

Patients and methods

CEAs were performed under local anesthesia. Patients were considered symptomatic (SY) if neurological signs appeared after the cross-clamping phase. In SY patients shunt insertion was performed. CoW on CT angiograms (CTa) were analyzed offline and categorized as non-functional (missing or hypoplastic collaterals) or functional collaterals by three neuroradiologists. Near-infrared spectroscopy (NIRS) was performed throughout the procedure.

Results

Based on CTa, 67 incomplete circles were found, 54 were asymptomatic (ASY) and 13 were SY. No complete CoW was found among the SY patients. Significant differences could be detected between incomplete and complete circles between ASY and SY groups (Chi-square: 6.08; p = 0.013). The anterior communicating artery was missing or hypoplastic in 5/13 SY cases. There were no cases of the non-functional anterior communicating arteries in the ASY group (Chi-square: 32.9; p = 10^-8). A missing or non-functional bilateral posterior communicating artery was observed in 9/13 SY and in 9/81 ASY patients (Chi-square: 24.4; p = 10^-7). NIRS had a sensitivity of 76.9% and a specificity of 74.5% in detecting neurological symptoms.

Conclusions

Collateral ability of the CoW may be a risk factor for ischemic events during CEAs. Further studies should delineate whether the preoperative assessment of collateral capacity may be useful in decision-making about shunt use during CEA.

Cerebral oximetry monitoring by means of INVOS-4100 as a predictor of ischemic events during carotid endarterectomy

Background

Several methods have been proposed to monitor cerebral perfusion during carotid endarterectomy (CEA), with the purpose of minimizing the risk of perioperative stroke. The INVOS-4100 is able to detect cerebral oxygen saturation providing an intraoperative real-time monitoring system of cerebral oximetry. The aim of this study was to evaluate the performance of the INVOS-4100 in predicting cerebral ischemia during CEA.

Methods

Between January 2020 and May 2022, 68 consecutive patients were scheduled for CEA either under general anesthesia or regional anesthesia with deep and superficial cervical block. Vascular oxygen saturation was recorded continually through INVOS before and during clamping of the ICA. Awake testing was performed in the group of patients undergoing CEA under regional anesthesia.

Results

Sixty-eight patients were included; 43 were males (63.2%). Severe stenosis of the artery was present in 92%. Forty-one (60.3%) patients were monitored by INVOS, while 22 (39.7%) underwent awake testing. Mean clamping time was 20 ± 6.6 min. Patients undergoing awake testing had a lower hospital stay and ICU stay during admission (p = 0.011 and p = 0.007 respectively). Comorbidities correlated with a higher ICU stay (p < 0.05). The INVOS monitoring was able to predict ischemic events with a sensitivity of 98% (AUC = 0.976).

Conclusions

The present study demonstrates that cerebral oximetry monitoring was a strong predictor of cerebral ischemia, although it was not possible to determine the non-inferiority of cerebral oximetry compared to awake testing. Nonetheless, the use of cerebral oximetry evaluates only perfusion in the superficial brain tissue and an absolute rSO2 value corresponding to significant cerebral ischemia has not been established. Therefore, larger prospective studies that correlate cerebral oximetry with neurologic outcomes are needed.

Perioperative stroke during carotid endarterectomy: benefits of multimodal neuromonitoring - a case report

Background

Carotid endarterectomy is routinely performed after ischemic stroke due to carotid stenosis. Perioperative, cerebral blood flow and oxygenation can be monitored in different ways, but there is no clear evidence of a gold standard and a uniform guideline is lacking. Electroencephalography and near-infrared spectroscopy are among the most frequently used methods of neuromonitoring. Clinicians should be aware of their pitfalls and the added value of transcranial doppler.

Case presentation

We present the case of an 85-year old male with perioperative haemodynamic stroke during carotid endarterectomy. Ischemic stroke was caused by suddenly increased carotid stenosis resulting in major neurologic deficit. This was registered only by transcranial doppler, while surface electroencephalography and near-infrared spectroscopy failed to detect any significant change in cerebral perfusion, despite a large perfusion defect on computed tomography. Circulation was restored with endovascular treatment and neurologic deficit quickly resolved.

Conclusion

We strongly advocate the practice of multimodal neuromonitoring including transcranial doppler whenever possible to minimize the risk of persistent neurologic deficit due to perioperative stroke during carotid endarterectomy.

A single-center retrospective study with 1-year follow-up after CEA in patients with severe carotid stenosis with contralateral carotid artery occlusion

Objective

To analyze the risk factors associated with adverse events after carotid endarterectomy (CEA) in patients with unilateral severe carotid stenosis and contralateral occlusion.

Methods

Patients were recruited for CEA between August 2014 and February 2020. CEA was performed under general anesthesia. The carotid clamp time (CCT; long CCT: >20 min) is defined as the period between clamp-on and clamp-off for the stenotic carotid artery. The perioperative factors and postoperative adverse events were recorded. All patients were followed up for 1 year after CEA.

Results

Sixty subjects (65.8 ± 7.2 years; 54 males) were included. Patients with adverse events had significantly longer CCT than those without adverse events (60% vs. 40%, P = 0.013). Univariate logistic regression analysis showed that a history of diabetes was significantly associated with adverse events (OR, 0.190; 95% CI, 0.045–0.814; P = 0.025); long CCT was significantly associated with adverse events (OR, 8.500; 95% CI, 1.617–44.682; P = 0.011). After adjusting for confounding factors, including age, sex, BMI, diabetes, PSV, long CCT, non–use of shunt, and history of stroke or TIA, the associations between diabetes and adverse events (OR, 0.113; 95% CI, 0.013–0.959; P = 0.046) were statistically significant; the associations between long CCT and adverse events (OR, 1.301; 95% CI, 1.049–1.613; P = 0.017) were statistically significant.

Conclusions

A longer carotid clamp time (>20 min) and a history of diabetes may increase the risk of adverse events in patients with unilateral severe carotid stenosis and contralateral occlusion after CEA. With good preoperative evaluation and intraoperative monitoring, the use of shunts may not be needed intraoperatively in patients with unilateral severe carotid stenosis and contralateral occlusion.

Outcome analysis of synchronous carotid endarterectomy and cardiac surgery. Comparison of two anesthetic techniques after propensity score-matching

BACKGROUND

The aim of this study was to investigate the outcome of patients undergoing synchronous carotid endarterectomy and coronary and/or other cardiac surgery. The impact of anesthesia on the outcome was examined.

METHODS

A retrospective single-center observational study was performed, to investigate the outcome of 127 consecutive adult patients submitted to synchronous surgery from 2011 to 2019. Cooperative patient general anesthesia for carotid endarterectomy followed by standard general anesthesia for cardiac surgery and standard general anesthesia for the whole surgery were compared after a propensity score analysis.

RESULTS

Primary outcomes were 30-day mortality (3.1%), incidence of stroke (3.1%), and myocardial infarction (0.8%). Agitation upon awakening, postoperative cardiac troponin I release, the increase of serum creatinine, the occurrence of acute kidney injury and the need for continuous renal replacement therapy were the secondary outcomes. A binary logistic regression revealed that cardiopulmonary bypass use, standard general anesthesia for the whole surgery and the European risk score II, were the strongest predictors of any severe postoperative complications. After propensity score matching, general anesthesia for the whole surgery was significantly correlated with the occurrence of any severe postoperative complication (P=0.038).

CONCLUSIONS

Synchronous surgery was performed with acceptable mortality and complication rate even in combination with other than isolated coronary surgery. Cooperative patient general anesthesia during carotid endarterectomy, was not inferior to general anesthesia in this setting.

Guideline on carotid surgery for stroke prevention: updates from the Italian Society of Vascular and Endovascular Surgery. A trend towards personalized medicine

BACKGROUND

This guideline (GL) on carotid surgery as updating of "Stroke: Italian guidelines for Prevention and Treatment" of the ISO-SPREAD Italian Stroke Organization-Group, has recently been published in the National Guideline System and shared with the Italian Society of Vascular and Endovascular Surgery (SICVE) and other Scientific Societies and Patient's Association.

METHODS

GRADE-SIGN version, AGREE quality of reporting checklist. Clinical questions formulated according to the PICO model. Recommendations developed based on clinical questions by a multidisciplinary experts' panel and patients' representatives. Systematic reviews performed for each PICO question. Considered judgements filled by assessing the evidence level, direction, and strength of the recommendations.

RESULTS

The panel provided indications and recommendations for appropriate, comprehensive, and individualized management of patients with carotid stenosis. Diagnostic and therapeutic processes of the best medical therapy, carotid endarterectomy (CEA), carotid stenting (CAS) according to the evidences and the judged opinions were included. Symptomatic carotid stenosis in elective and emergency, asymptomatic carotid stenosis, association with ischemic heart disease, preoperative diagnostics, types of anesthesia, monitoring in case of CEA, CEA techniques, comparison between CEA and CAS, post-surgical carotid restenosis, and medical therapy are the main topics, even with analysis of uncertainty areas for risk-benefit assessments in the individual patient (personalized medicine [PM]).

CONCLUSIONS

This GL updates on the main recommendations for the most appropriate diagnostic and medical-surgical management of patients with atherosclerotic carotid artery stenosis to prevent ischemic stroke. This GL also provides useful elements for the application of PM in good clinical practice.

Routine or selective carotid artery shunting for carotid endarterectomy (and different methods of monitoring in selective shunting)

BACKGROUND

Temporary interruption of cerebral blood flow during carotid endarterectomy can be avoided by using a shunt across the clamped section of the carotid artery. The shunt may improve the outcome. This is an update of a Cochrane review originally published in 1996 and previously updated in 2002, 2009, and 2014.

OBJECTIVES

To assess the effect of routine versus selective or no shunting, and to assess the best method for selective shunting on death, stroke, and other complications in people undergoing carotid endarterectomy under general anaesthesia.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register (last searched April 2021), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2021, Issue 4), MEDLINE (1966 to April 2021), Embase (1980 to April 2021), and the Science Citation Index Expanded (SCI-EXPANDED) (1980 to April 2021). We also searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform, and handsearched relevant journals, conference proceedings, and reference lists.

SELECTION CRITERIA

Randomised and quasi-randomised trials of routine shunting compared with no shunting or selective shunting, and trials that compared different shunting policies in people undergoing carotid endarterectomy.

DATA COLLECTION AND ANALYSIS

Three independent review authors performed data extraction, selection, and analysis. A pooled Peto odds ratio (OR) and 95% confidence interval (CI) were computed for all outcomes of interest. Best and worse case scenarios were also calculated in case of unavailable data. Two authors independently assessed risk of bias, and quality of evidence using GRADE.

MAIN RESULTS

No new trials were found for this updated review. Thus, six trials involving 1270 participants are included in this latest review: three trials involving 686 participants compared routine shunting with no shunting, one trial involving 200 participants compared routine shunting with selective shunting, one trial involving 253 participants compared selective shunting with and without near-infrared refractory spectroscopy monitoring, and the other trial involving 131 participants compared shunting with a combination of electroencephalographic and carotid pressure measurement with shunting by carotid pressure measurement alone. Only three trials comparing routine shunting and no shunting were eligible for meta-analysis. Major findings of this comparison found that the routine shunting had less risk of stroke-related death within 30 days of surgery (best case) than no shunting (Peto odds ratio (OR) 0.13, 95% confidence interval (CI) 0.02 to 0.96, I² not applicable, P = 0.05, low-quality evidence), the routine shunting group had a lower stroke rate within 24 hours of surgery (Peto odds ratio (OR) 0.15, 95% CI 0.03 to 0.78, I² = not applicable, P = 0.02, low-quality evidence), and ipsilateral stroke within 30 days of surgery (best case) (Peto OR 0.41, 95% CI 0.18 to 0.97, I² = 52%, P = 0.04, low-quality evidence) than the no shunting group. No difference was found between the groups in terms of postoperative neurological deficit between selective shunting with and without near-infrared refractory spectroscopy monitoring. However, this analysis was inadequately powered to reliably detect the effect. There was no difference between the risk of ipsilateral stroke in participants selected for shunting with the combination of electroencephalographic and carotid pressure assessment compared with pressure assessment alone, although again the data were limited.

AUTHORS' CONCLUSIONS

This review concluded that the data available were too limited to either support or refute the use of routine or selective shunting in carotid endarterectomy when performed under general anaesthesia. Large-scale randomised trials of routine shunting versus selective shunting are required. No method of monitoring in selective shunting has been shown to produce better outcomes.

Anesthetic management of carotid endarterectomy: an update from Italian guidelines

BACKGROUND AND AIMS

In order to systematically review the latest evidence on anesthesia, intraoperative neurologic monitoring, postoperative heparin reversal, and postoperative blood pressure management for carotid endarterectomy. The present review is based on a single chapter of the Italian Health Institute Guidelines for diagnosis and treatment of extracranial carotid stenosis and stroke prevention.

METHODS AND RESULTS

A systematic article review focused on the previously cited topics published between January 2016 and October 2020 has been performed; we looked for both primary and secondary studies in the extensive archive of Medline/PubMed and Cochrane library databases. We selected 14 systematic reviews and meta-analyses, 13 randomized controlled trials, 8 observational studies, and 1 narrative review. Based on this analysis, syntheses of the available evidence were shared and recommendations were indicated complying with the GRADE-SIGN version methodology.

CONCLUSIONS

From this up-to-date analysis, it has emerged that any type of anesthesia and neurological monitoring method is related to a better outcome after carotid endarterectomy. In addition, insufficient evidence was found to justify reversal or no-reversal of heparin at the end of surgery. Furthermore, despite a low evidence level, a suggestion for blood pressure monitoring in the postoperative period was formulated.

Carotid Endarterectomy

Stroke is the second leading cause of death worldwide. One of the main causes of stroke is carotid artery stenosis. Stenosis with atherosclerosis in the carotid artery can cause stroke by hemodynamic ischemia or artery to artery embolism. A most common surgical intervention for carotid artery stenosis is carotid endarterectomy (CEA). Many studies on CEA have been reported and suggested medical indications. For symptomatic carotid stenosis, generally, CEA may be indicated for patients with more than 50% stenosis and is especially beneficial in men, patients aged 75 years or older, and patients who underwent surgery within 2 weeks of their last symptoms. For asymptomatic carotid stenosis, CEA may be indicated for those with more than 60% stenosis, though each guideline has different suggestions in detail. In order to evaluate the indication for CEA in each case, it is important to assess risks for CEA carefully including anatomical factors and comorbidities, and to elaborate each strategy for each operation based on preoperative imaging studies including carotid ultrasonography, magnetic resonance imaging and angiography. In surgery there are many tips on operative position, procedure, shunt usage and monitoring to perform a safe and smooth operation. Now that carotid artery stenting has been rapidly developed, better understanding for CEA is required to treat carotid artery stenosis adequately. This chapter must be a good help to understand CEA well.

A narrative review of the pathophysiology of ischemic stroke in carotid plaques: a distinction versus a compromise between hemodynamic and embolic mechanism

Atherosclerotic carotid artery stenosis causes about 10–20% of all ischemic strokes through two main mechanisms: hemodynamic impairment in case of significant stenosis and thromboembolism from an atherosclerotic plaque regardless of the degree of stenosis. The latter is the most frequent mechanism and appear to result from embolization from a vulnerable atherosclerotic plaque or acute occlusion of the carotid artery and propagation of thrombus distally. Downstream infarcts may occur in a territory of major cerebral artery or at the most distal areas between two territories of major cerebral arteries, the so-called watershed (WS), or border zone area. Although WS infarcts, especially deep WS infarct, were historically thought to be due to hemodynamic compromise, the role of microembolism has also been documented, both mechanisms may act synergistically to promote WS infarcts. Routine and more advanced imaging techniques may provide information on the underlying mechanism involved in ipsilateral ischemic stroke. A better understanding of ischemic stroke pathogenesis in carotid stenosis may limit the use of routine non-selective shunt, whose benefit-risk balance is debated, to patients with hemodynamic impairment.

After reviewing existing evidence underpinning the contribution of the two mechanisms in downstream ischemic stroke and the various imaging techniques available to investigate them, we will focus on the pathogenesis of WS infarcts that remains debated.

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.

Carotid Stump Pressure and Contralateral Internal Carotid Stenosis Ratio During Carotid Endarterectomies: 1D-0D Hemodynamic Simulation of Cerebral Perfusion

Objective: We selectively place carotid shunting when ipsilateral mean stump pressure is less than 40 mmHg during carotid endarterectomy (CEA). This study aimed to assess the validity of our selective shunting criterion by 1D-0D hemodynamic simulation technology.

Materials and Methods: We retrospectively reviewed 88 patients (95 cases) of CEA and divided them into two groups based on the degree of contralateral internal carotid artery (ICA) stenosis ratio, which was determined as severe when the peak systolic velocity ratio of the ICA to the common carotid artery was ≥4 by carotid duplex ultrasonography. Patients with severe stenosis or occlusion in contralateral ICA were classified as hypoperfusion group, and those without such contralateral ICA obstruction were classified as control group.

Results: Perioperatively, the mean carotid stump pressures were 33 mmHg in hypoperfusion group and 46 mmHg in the control group (P=0.006). We simulated changes in carotid stump pressure according to the changes in the contralateral ICA stenosis ratio. 1D-0D simulation indicated a sharp decline in carotid stump pressure when the contralateral stenosis ratio was >50%, while peripheral pressure of the middle cerebral arteries declined sharply at a ≥70% contralateral stenosis ratio. At this ratio, the direction of the ipsilateral cerebral arterial flow became inverted, the carotid stump pressure became dependent on the basilar artery circulation, and the ipsilateral middle cerebral artery became hypoperfused.

Conclusion: Our clinical and computer-simulated results confirmed the validation of our carotid shunting criterion and suggested that contralateral ICA stenosis ratio over 70% is a safe indication of selective shunting during CEA.

Middle cerebral artery pressure laterality in patients with symptomatic ICA stenosis

An internal carotid artery (ICA) stenosis can potentially decrease the perfusion pressure to the brain. In this study, computational fluid dynamics (CFD) was used to study if there was a hemispheric pressure laterality between the contra- and ipsilateral middle cerebral artery (MCA) in patients with a symptomatic ICA stenosis. We further investigated if this MCA pressure laterality (ΔPMCA) was related to the hemispheric flow laterality (ΔQ) in the anterior circulation, i.e., ICA, proximal MCA and the proximal anterior cerebral artery (ACA). Twenty-eight patients (73±6 years, range 59-80 years, 21 men) with symptomatic ICA stenosis were included. Flow rates were measured using 4D flow MRI data (PC-VIPR) and vessel geometries were obtained from computed tomography angiography. The ΔPMCA was calculated from CFD, where patient-specific flow rates were applied at all input- and output boundaries. The ΔPMCA between the contra- and ipsilateral side was 6.4±8.3 mmHg (p<0.001) (median 3.9 mmHg, range -1.3 to 31.9 mmHg). There was a linear correlation between the ΔPMCA and ΔQICA (r = 0.85, p<0.001) and ΔQACA (r = 0.71, p<0.001), respectively. The correlation to ΔQMCA was weaker (r = 0.47, p = 0.011). In conclusion, the MCA pressure laterality obtained with CFD, is a promising physiological biomarker that can grade the hemodynamic disturbance in patients with a symptomatic ICA stenosis.

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.

Safe carotid endarterectomy: "one fits all strategy"

INTRODUCTION

Carotid artery stenosis of 50% or more in the extracranial internal carotid artery is responsible for 10-15% of all strokes. Interventional treatment options include carotid endarterectomy and carotid artery stenting, where endarterectomy is proven to be superior.

AIM

In this study, we report the carotid endarterectomy results of patients we operated on using the strategy we termed the "one fits all strategy".

MATERIAL AND METHODS

Seventy-six patients undergoing carotid endarterectomy between July 2016 and April 2020 were retrospectively studied. Conventional endarterectomy under general anesthesia with primary closure of the arteriotomy was performed in all patients. We used a near infrared spectroscopy oximeter to measure regional cerebral oxygenation continuously throughout the surgery.

RESULTS

The mean age of the patients was 70.96 8.15 years. There were 52 male and 24 female patients. The mean follow-up time was 20.6 ±13.6 months. Coronary artery disease was detected in 52 (73.6%) patients. Coronary artery bypass operation was indicated in 19 patients in whom a staged approach was performed in 13 and a reverse staged approach in 1. There were two perioperative strokes one of which recovered fully spontaneously and the other partially with physiotherapy. Eight cases were revised due to hematoma formation.

CONCLUSIONS

Carotid endarterectomy continues to prove its safety in carotid artery stenosis patients. Continuous cerebral oxygenation monitoring is indispensable for carotid surgery. Despite discrepancies in surgical techniques, we believe that "one fits all strategy: general anesthesia, conventional endarterectomy without patch plasty, never shunter and always NIRS monitorization" may be used safely in patients undergoing carotid endarterectomy.

Surgical Technique for Carotid Endarterectomy: Current Methods and Problems

Over the last 60 years, many reports have investigated carotid endarterectomy (CEA) and techniques have thus changed and improved. In this paper, we review the recent literature regarding operational maneuvers for CEA and discuss future problems for CEA. Longitudinal skin incision is common, but the transverse incision has been reported to offer minimal invasiveness and better cosmetic effects for CEA. Most surgeons currently use microscopy for dissection of the artery and plaque. Although no monitoring technique during CEA has been proven superior, multiple monitors offer better sensitivity for predicting postoperative neurological deficit. To date, data are lacking regarding whether routine shunt or selective shunt is better. Individual surgeons thus need to select the method with which they are more comfortable. Many surgical techniques have been reported to obtain distal control of the internal carotid artery in patients with high cervical carotid bifurcation or high plaque, and minimally invasive techniques should be considered. Multiple studies have shown that patch angioplasty reduces the risks of stroke and restenosis compared with primary closure, but few surgeons in Japan have been performing patch angioplasty. Most surgeons thus experience only a small volume of CEAs in Japan, so training programs and development of in vivo training models are important.

Importance of cerebral angiography and intraoperative neuromonitoring in carotid endarterectomy

It is an increasingly common practice to indicate a carotid endarterectomy procedure based on the information provided by non-invasive tests like Duplex ultrasound, MR angiography or CT angiography, thereby obviating the performance of a conventional cerebral angiography. We present a case of symptomatic left carotid artery 80% stenosis in which cerebral angiography showed absence of the right A1 segment and bilateral anterior cerebral artery territories that filled only from a left injection. Just 90seconds after carotid artery clamping at the neck, brain oximetry and somatosensory evoked potentials significantly dropped, that recovered after immediate clamp removal. Endarterectomy was dismissed and a carotid stent was successfully placed. This case highlights the importance of knowing the dynamics of cerebral blood circulation distal to the stenosis. If endarterectomy had been attempted, unawareness of the information provided by the cerebral angiography would have likely result in severe bi-hemispheric ischemia.

The Role of Carotid Stump Pressure in Carotid Endarterectomy: A Systematic Review and Meta-Analysis

This review evaluates the carotid stump pressure (CSP)’s role as a single parameter at any given pressure as an indicator for selective shunting, or vice versa, in carotid endarterectomy (CEA). A systematic review of literature in MEDLINE and the Cochrane Library from 1969 to 2019 was conducted. The primary end point was set at 0 to 30-day mortality, ischemic stroke (IS), transient ischemic attack (TIA), and a secondary point at recognition of an optimal CSP pressure. The data was subjected to meta-analytics. The odds ratio (OR) was reported at 95% confidence interval (CI). This study has been registered with PROSPERO: CRD42019119851. The pooled analysis on the primary endpoint of IS demonstrated higher incidence of stroke in shunted CEAs solely based on CSP measurement alone (OR, 0.14, 95%CI: 0.08–0.24, I²=48%, p<0.001). Sub group analysis demonstrated similar patterns at 25 mmHg (OR, 0.06, 95%CI: 0.01–0.5, p<0.01), 30 mmHg (OR, 0.07, 95%CI: 0.01–0.63, p=0.02) and 40 mmHg (OR, 0.23, 95%CI: 0.09–0.57, p<0.01). This effect on end points of mortality and TIA demonstrated no benefit in either direction. CSP, as a single criterion, is not a reliable parameter in reduction of TIA, mortality, and IS at any given pressure range.

Comparison of the effect of sevoflurane or propofol anesthesia on the regional cerebral oxygen saturation in patients undergoing carotid endarterectomy: a prospective, randomized controlled study

Background

The monitoring of regional cerebral oxygen saturation (SrO₂) using near-infrared spectroscopy is useful method to detect cerebral ischemia during. Sevoflurane and propofol decrease cerebral metabolic rate (CMRO₂) in a similar manner, but the effects on the cerebral blood flow (CBF) are different. We hypothesized that the effects of sevoflurane and propofol on SrO₂ were different in patients with deficits of CBF. This study compared the effect of sevoflurane and propofol on SrO₂ of patients undergoing cerebral endarterectomy (CEA).

Method

Patients undergoing CEA were randomly assigned to the sevoflurane or propofol group (n = 74). The experiment was preceded in 2 stages based on carotid artery clamping. The first stage was from induction of anaesthesia to immediately before clamping of the carotid artery, and the second stage was until the end of the operation after clamping of the carotid artery. Oxygen saturation (SrO₂, SpO₂), haemodynamic variables (blood pressure, heart rate), respiratory parameters (end-tidal carbon dioxide tension, inspired oxygen tension), concentration of anesthetics, and anesthesia depth (bispectral index score) were recorded.

Results

During stage 1 period (before carotid artery clamping), the mean value of the relative changes in SrO₂ was higher (P = 0.033) and the maximal decrease in SrO₂ was lower in the sevoflurane group compared with the propofol group (P = 0.019) in the contralateral (normal) site. However, there is no difference in ipsilateral site (affected site). SrO₂ decreased after carotid artery clamping and increased after declamping, but the difference was not significant between two groups. Changes in mean arterial blood pressure was lower in sevoflurane group than propofol group after the carotid artery declamping (P = 0.048).

Conclusion

Propofol-remifentanil anesthesia was comparable with sevoflurane-remifentanil anesthesia in an aspect of preserving the SrO₂ in patients undergoing carotid endarterectomy.

Trial registration

Clinical Trials.gov identifier: NCT02609087, retrospectively registered on November 18, 2015.

Purine nucleoside use as surrogate markers of cerebral ischaemia during local and general anaesthetic carotid endarterectomy

Objectives:

In periods of cerebral ischaemia, adenosine triphosphate is metabolised, leading to accumulation of adenosine inosine and hypoxanthine. These can be measured in real time using peripheral blood samples intraoperatively. The primary aim of this study was to describe changes in purine concentrations in a cohort of patients undergoing carotid endarterectomy under general anaesthetic, and to evaluate correlation between changes in values with major perioperative steps. The secondary aim was to compare changes in concentrations with a previous cohort of patients who had undergone carotid endarterectomy under local anaesthetic.

Methods:

This was a prospective observational study. Purine concentrations were determined from arterial line samples and measured via an amperometric biosensor at specific time points during carotid endarterectomy. Mean arterial pressure was manipulated to maintain steady cerebral perfusion pressure throughout the procedure. These results were analysed against data from a cohort of patients who underwent carotid endarterectomy under local anaesthetic in previously published work.

Results:

Valid results were obtained for 37 patients. Purine concentrations at baseline were 3.02 ± 1.11 µM and 3.16 ± 1.85 µM for the unshunted and shunted cohorts, respectively. There was no significant change after 30 min of carotid clamping at 2.07 ± 0.89 and 2.4 ± 3.09 µM, respectively (both p > 0.05). Peak purine during the clamp phase in the loco-regional anaesthetic cohort was 6.70 ± 3.4 µM, which was significantly raised compared to both general anaesthetic cohorts (p = 0.004). There were no perioperative neurological events in either cohort.

Conclusion:

This small study does not demonstrate conclusive evidence that purine nucleosides can be used as a marker of cerebral ischaemia; the comparisons to the loco-regional anaesthetic data offer information about differences in the cerebral adenosine triphosphate metabolism between general anaesthetic and loco-regional anaesthetic. We hypothesise that the lack of a rise in purine nucleosides under general anaesthetic may be caused by a decrease in the cerebral metabolic rate and loss of metabolic rate-blood flow coupling caused by general anaesthetic agents.

[Advances in surgical treatment of ischemic cerebrovascular disease]

Restoration of cerebral blood flow is particularly important for the treatment of ischemic cerebrovascular disease. It is notable that surgical approaches play a unique role in treating this devastating disease. Among them, mechanical thrombectomy facilitates rapid and effective recanalization of occluded intracranial large vessels causing ischemic stroke, which contributes to improvement of cerebral perfusion in the ischemic penumbra; decompressive craniectomy is an important therapeutic option for acute massive cerebral infarction, and the timing of surgery determines the final clinical outcomes; for carotid endarterectomy in carotid-artery stenosis, individualized surgical plan is important for the safety and effectiveness of the operation; in the surgical revascularization of Moyamoya disease, precise evaluation of clinical and radiological characteristics, optimal surgical strategies and accuracy of intraoperative judgment will yield maximal therapeutic effects; and hybrid surgery is feasible for the therapy of complex ischemic cerebrovascular diseases, such as extracranial/intracranial arteries tandem stenosis and symptomatic chronic total occlusion of carotid artery. This paper reviews recent technical and clinical advances in the surgical treatment of ischemic cerebrovascular disease.

Carotid endarterectomy with primary closure versus patch angioplasty in patients with symptomatic and significant stenosis: protocol for a systematic review with meta-analyses and trial sequential analysis of randomised clinical trials

INTRODUCTION

Use of patch angioplasty in carotid endarterectomy (CEA) is suggested to reduce the risk of restenosis and recurrent ipsilateral stroke. The objective is to conduct a systematic review with meta-analysis and trial sequential analysis as well as Grading of Recommendations Assessment, Development and Evaluation (GRADE) assessments comparing the benefits and harms of CEA with primary closure of the arterial wall versus CEA with patch angioplasty in patients with a symptomatic and significant carotid stenosis.

METHODS AND ANALYSIS

The review shall be conducted according to this published protocol following the recommendations of the 'Cochrane' and reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Randomised clinical trials comparing CEA with primary closure of the arterial wall versus CEA with patch angioplasty (regardless of used patch materials) in human adults with a symptomatic and significant carotid stenosis will be included. Primary outcomes are all-cause mortality at maximal follow-up, health-related quality of life and serious adverse events. Secondary outcomes are symptomatic or asymptomatic arterial occlusion or restenosis, and non-serious adverse events. We will primarily base our conclusions on meta-analyses of trials with overall low risk of bias. However, if pooled point estimates of all trials are similar to pooled point estimates of trials with overall low risk of bias and there is lack of a statistical significant interaction between estimates from trials with overall high risk of bias and trials with overall low risk of bias we will consider the precision achieved in all trials as the result of our meta-analyses.

ETHICS AND DISSEMINATION

The proposed systematic review will collect and analyse secondary data from published studies therefor ethical approval is not required. The results of the systematic review will be disseminated by publication in a peer-review journal and submitted for presentation at relevant conferences.

PROSPERO REGISTRATION NUMBER

CRD42014013416.

Surgical Pitfalls in Carotid Endarterectomy: A New Step-By-Step Approach

Carotid endarterectomy (CEA) is a surgical intervention that may prevent stroke in asymptomatic and symptomatic patients. Our aim was to examine the microsurgical anatomy of carotid artery and other related neurovascular structures to summarize the CEA that is currently applied in ideal conditions. The upper necks of 2 adult cadavers (4 sides) were dissected using ×3 to ×40 magnification. The common carotid artery, external carotid artery (ECA), and internal carotid artery were exposed and examined. The surgical steps of CEA were described using 3-D cadaveric photos and computed tomography angiographic pictures obtained with help of OsiriX imaging software program. Segregating certain neurovascular and muscular structures in the course of CEA significantly increased the exposure. The division of facial vein allowed for internal jugular vein to be mobilized more laterally and dividing the posterior belly of digastric muscle resulted in an additional dorsal exposure of almost 2 cm. Isolating the ansa cervicalis that pulls hypoglossal nerve inferiorly allowed hypoglossal nerve to be released safely medially. The locations of the ECA branches alter depending on their anatomical variations. The hypoglossal nerve, glossopharyngeal nerve, and accessory nerve pierce the fascia of the upper part of the carotid sheath and they are vulnerable to injury because of their distinct courses along the surgical route. Surgical exposure in CEA requires meticulous dissection and detailed knowledge of microsurgical anatomy of the neck region to avoid neurovascular injuries and to determine the necessary surgical maneuvers in cases with neurovascular variations.

Incomplete circle of Willis is associated with a higher incidence of neurologic events during carotid eversion endarterectomy without shunting

OBJECTIVE

A complete circle of Willis (CoW) is considered an important collateral network to maintain blood flow during cross-clamping in carotid endarterectomy (CEA). The aim of this study was to evaluate the impact of an incomplete CoW with isolated middle cerebral artery (iMCA) on immediate neurologic events (INEs) after CEA.

METHODS

We prospectively collected the clinical data and outcomes of 902 patients who underwent CEA under general anesthesia between 2013 and 2015. All patients had preoperative computed tomography angiography of the extracranial and intracranial cerebral circulation. Indications were asymptomatic (52%) and symptomatic (48%) carotid artery disease. Patients who had CEA with shunt (n = 35) and those with inadequate intracranial imaging to assess CoW were excluded (n = 322) only. Computed tomography angiography images were reviewed retrospectively and independently by two vascular radiologists who were blinded for treatment outcomes. Imaging assessment included the vertebral and carotid circulation and each segment of the CoW, which was classified as normal, hypoplastic (diameter < 0.8 mm) or absent. The ipsilateral MCA was considered isolated if there was an absence of the anterior and posterior communicating branches from the contralateral carotid or posterior circulations. INE was defined as any transient ischemic attack (TIA) and stroke diagnosed immediately after the procedure.

RESULTS

Of the 545 included patients (331 males; mean age, 69 ± 8 years), 12 (2.2%) had a stroke in the postoperative period. There were 20 INEs (8 strokes and 12 TIAs). A complete CoW was rare; it was only detected in 19 patients (3.5%) and an iMCA was found in 34 patients (6.3%). When at least one collateral circulation was complete (in 330 patients), we observed only four INEs (1.2%). Of the 34 patients with an iMCA, 8 (24%) had INE (6 TIAs and 2 strokes). Overall, iMCA was an independent predictor of INEs (odds ratio, 11.12; 95% confidence interval, 3.57-35.87; P < .001). With logistic regression, the model included hypertension, smoking, diabetes, hyperlipidemia, carotid clamping time (minutes), contralateral significant internal carotid artery stenosis of greater than 90%, ipsilateral significant internal carotid artery stenosis of greater than 90%, preoperative symptoms in 6 months, and iMCA; above iMCA only symptomatic patients had significant risk (odds ratio, 3.34; 95% confidence interval, 1.19-9.73; P = .02), whereas all other parameters were not significant.

CONCLUSIONS

An iMCA carries more than a 10-fold higher the risk of INEs after CEA with cross-clamping without shunt protection. In these patients, routine shunting is recommended to prevent INEs.

One-year experience in carotid endarterectomy combining general anaesthesia with preserved consciousness and sequential carotid cross-clamping

Background and aim of the work: We report 1-year single-centre experience in carotid endarterectomy (CEA) combining general anaesthesia with preserved consciousness (GAPC) and standardized carotid sequential cross-clamping, for our protocol effectiveness evaluation in reduction of perioperative stroke, death or cardiologic complications. Methods: We considered all patients who underwent CEA in 2016. All patients underwent superficial cervical plexus block and GAPC with Remifentanil. The surgical technique consisted of common carotid artery (CCA) cross-clamping, carotid bifurcation isolation, external (ECA) and internal carotid artery (ICA) cross-clamping. After CCA cross-clamping, we performed a neurological tolerance test (NTT); this allowed selective shunting only for positive NTT. Primary end-points were: transient ischemic attack (TIA)/stroke, myocardial infarction, death in perioperative period. Secondary end-points were: carotid shunting, peripheral cranial nerves injuries (PCNI), GAPC intolerance, other complications, reintervention in perioperative period, length of hospital stay. Results: 104 consecutive patients underwent CEA with this protocol in the considered period. Twenty-seven (25.9%) patients were symptomatic. Mean clamping time was 48±13.5 minutes. Five cases (4.8%) requested internal carotid artery shunting. No TIA/stroke, myocardial infarction or death were recorded in the perioperative period. PCNI were observed in 19 cases (18.2%) in the immediate post-operative period; 16 of them (84.2%) showed complete or partial resolution at discharge. Only one patient (0.9%) showed GAPC intolerance. No other complication occurred. Three patients (2.9%) underwent reintervention for neck haematoma drainage. Mean hospital stay were 3±0.9 days. Conclusions: GAPC associated with sequential carotid cross-clamping appeared to be safe and effective in prevention of major neurological and cardiologic complications during CEA. (www.actabiomedica.it)

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

OBJECTIVE

The efficacy of selective shunting during carotid endarterectomy (CEA) using intraoperative monitoring (IOM) for detection of cerebral ischemia is well established. There is mounting evidence that monitoring of both electroencephalography (EEG) and somatosensory evoked potentials (SSEPs) increases the sensitivity of cerebral ischemia detection. Predictors of cerebral ischemia requiring selective shunt placement using IOM of both EEG and SSEPs have not been previously identified.

METHODS

Consecutive patients who underwent CEA between January 1, 2000, and December 31, 2010, were retrospectively analyzed. Primary end points were IOM changes at any time during the operation or IOM changes with carotid cross-clamping. Risk factors assessed included demographics; baseline comorbidities; severity of ipsilateral and contralateral disease; symptomatic status; and use of statin, antiplatelet, and beta-blocker medications. Univariate and multivariate logistic regression was used for analysis.

RESULTS

During the 11-year study period, a total of 758 patients underwent 804 CEAs (mean age, 70.6 ± 9.5 years; 59.8% male; 39.2% symptomatic) using IOM of both SSEPs and EEG for selective shunting guidance. Postoperative stroke rate was 1.37%; 27.1% of patients had significant SSEP or EEG changes, and 49.1% of these were clamp induced (within 5 minutes of cross-clamping). Of these patients, 83.2% received a shunt (11.4% overall). The most common reason that a shunt was not placed after cross-clamp-induced changes was that the changes resolved with further blood pressure elevation (8 of 17 patients). Clamp-induced IOM changes were predictive of postoperative stroke (odds ratio [OR], 5.5; P = .005). Risk factors for clamp-induced IOM changes were contralateral carotid occlusion (OR, 2.5; P = .01), symptomatic stenosis (OR, 1.8; P = .006), and diabetes (OR, 1.6; P = .03), whereas there was a trend toward increased risk with female sex (OR, 1.5; P = .08). Risk factors for any IOM change (clamp and nonclamp induced) were symptomatic carotid stenosis (OR, 1.8; P < .001), use of beta blockers (OR, 1.5; P = .03), and female sex (OR, 1.5; P = .02).

CONCLUSIONS

Whereas some patients can be expected to experience IOM changes by monitoring of SSEPs and EEG, a much smaller percentage will receive a shunt. Contralateral carotid occlusion, symptomatic stenosis, diabetes, and female sex increase the risk of clamp-induced IOM changes and should be anticipated to need a shunt. Patients receiving beta blockers are likely to experience IOM changes during the operation that are not associated with clamping.

Cost-Effectiveness of Two Decision Strategies for Shunt Use During Carotid Endarterectomy

Background

Arterial shunting during carotid endarterectomy (CEA) is essential in some patients because of insufficient cerebral perfusion during cross-clamping. However, the optimal diagnostic modality identifying these patients is still debated. None of the currently used modalities has been proved superior to another. The aim of this study was to assess the cost-effectiveness of two modalities, stump pressure measurement (SPM) versus electroencephalography (EEG) combined with transcranial Doppler (TCD) during CEA.

Methods

Two retrospective cohorts of consecutive patients undergoing CEA with different intraoperative neuromonitoring strategies (SPM vs. EEG/TCD) were analyzed. Clinical data were collected from patient hospital records. Primary clinical outcome was in-hospital stroke or death. Total admission costs were calculated based on volumes of healthcare resources. Analyses of effects and costs were adjusted for clinical differences between patients by means of a propensity score, and cost-effectiveness was estimated.

Results

A total of 503 (239 SPM; 264 EEG/TCD) patients were included, of whom 19 sustained a stroke or died during admission (3.3 vs. 4.2%, respectively, adjusted risk difference 1.3% (95% CI −2.3–4.8%)). Median total costs were €4946 (IQR 4424–6173) in the SPM group versus €7447 (IQR 6890–8675) in the EEG/TCD group. Costs for neurophysiologic assessments were the main determinant for the difference.

Conclusions

Given the evidence provided by this small retrospective study, SPM would be the favored strategy for intraoperative neuromonitoring if cost-effectiveness was taken into account when deciding which strategy to adopt.

Cerebral monitoring during carotid endarterectomy by transcranial Doppler ultrasonography

Purpose

To evaluate the efficacy and safety of cerebral monitoring by transcranial Doppler ultrasonography (TCD) for the detection of cerebral ischemia during carotid endarterectomy (CEA).

Methods

From August 2004 to December 2013, 159 CEAs were performed in a tertiary hospital. All procedures were performed under general anesthesia. Intraoperative TCD was routinely used to detect cerebral ischemia. Of the 159 patients, 102 patients were included in this study, excluding 27 patients who had a poor transtemporal isonation window and 30 patients who used additional cerebral monitoring systems such as electroencephalography or somatosensory evoked potentials. When mean flow velocity in the ipsilateral middle cerebral artery decreased by >50% versus baseline during carotid clamping carotid shunting was selectively performed. The carotid shunt rate and incidence of perioperative (<30 days) stroke or death were investigated by reviewing medical records.

Results

Carotid shunting was performed in 31 of the 102 patients (30%). Perioperative stroke occurred in 2 patients (2%); a minor ischemic stroke caused by embolism in one and an intracerebral hemorrhage in the other. Perioperative death developed in the latter patient.

Conclusion

TCD is a safe cerebral monitoring tool to detect cerebral ischemia during CEA. It can reduce use of carotid shunt.

Oxidative Stress and Total Antioxidant Status During Internal Carotid Artery Clamping with or without Shunting: An Experimental Pilot Study

Background

The exact role of shunting during carotid endarterectomy remains controversial and unclear. The aim of this experimental study was to investigate to what degree carotid clamping may induce changes in the cerebral oxidative status and to focus on the relation of these changes with shunt insertion.

Material/Methods

Forty New-Zealand rabbits were randomized into 4 groups: group 1 classifying animals with carotid shunt and patent contralateral carotid artery; group 2 shunt and occlusion of the contralateral carotid artery; group 3 no-shunt and patent contralateral carotid artery; and group 4 no-shunt and occlusion of the contralateral carotid artery. Blood samples were collected from the ipsilateral internal jugular vein, immediately after carotid clamping (time 0), and then at 5, 10, 15, 30, and 60 minutes afterwards. Evaluation of oxidative stress was accomplished by measuring the lag-time, representing the initial phase of oxidation, rate of accumulation (RA), showing concentration of free oxygen radical and total antioxidant status (TAS) representing antioxidant composition of serum.

Results

Lag-time was significantly different in time points 0, 30 and 60 minutes within each different group. TAS was significantly different in time points 0, 15 and 60 min and RA in time points 0, 5, 10 and 60 min within each different group. 60 minutes after carotid clamping, the rate of accumulation as well as lag-time and TAS were increased in all groups, independently of using or not shunting or the presence of contralateral occlusion. After comparing groups 1, 2 and 3 regarding lag-time, TAS and RA, we did not find statistical difference among the groups at any time point. On the contrary, groups 1, 2 and 3 did show significantly different values comparing to group 4 after 60 min of occlusion.

Conclusions

Our experimental work based on cerebral metabolism found a significantly higher oxidative stress in models with contralateral carotid occlusion. The use of shunt in all other models did not have any influence on oxidative response. Future human studies should focus on the relation of oxidative status and shunt insertion to determine the benefit of selective or routine shunting during CEA.

A comparison of results with eversion versus conventional carotid endarterectomy from the Vascular Quality Initiative and the Mid-America Vascular Study Group

OBJECTIVE

Carotid endarterectomy (CEA) is usually performed with eversion (ECEA) or conventional (CCEA) technique. Previous studies report conflicting results with respect to outcomes for ECEA and CCEA. We compared patient characteristics and outcomes for ECEA and CCEA.

METHODS

Deidentified data for CEA patients were obtained from the Society for Vascular Surgery Vascular Quality Initiative (SVS VQI) database for years 2003 to 2013. Second (contralateral) CEA, reoperative CEA, CEA after previous carotid stenting, or CEA concurrent with cardiac surgery were excluded, leaving 2365 ECEA and 17,155 CCEA for comparison. Univariate analysis compared patients, procedures, and outcomes. Survival analysis was also performed for mortality. Multivariate analysis was used selectively to examine the possible independent predictive value of variables on outcomes.

RESULTS

Groups were similar with respect to sex, demographics, comorbidities, and preoperative neurologic symptoms, except that ECEA patients tended to be older (71.3 vs 69.8 years; P < .001). CCEA was more often performed with general anesthesia (92% vs 80%; P < .001) and with a shunt (59% vs 24%; P < .001). Immediate perioperative ipsilateral neurologic events (ECEA, 1.3% vs CCEA, 1.2%; P = .86) and any ipsilateral stroke (ECEA, 0.8% vs CCEA, 0.9%; P = .84) were uncommon in both groups. ECEA tended to take less time (median 99 vs 114 minutes; P < .001). However, ECEA more often required a return to the operating room for bleeding (1.4% vs 0.8%; P = .002), a difference that logistic regression analysis showed was only partly explained by differential use of protamine. Life-table estimated 1-year freedom from any cortical neurologic event was similar (96.7% vs 96.7%). Estimated survival was similar comparing ECEA with CCEA at 1 year (96.7% vs 95.9%); however, estimated survival tended to decline more rapidly in ECEA patients after ∼2 years. Cox proportional hazards modeling confirmed that independent predictors of mortality included age, coronary artery disease, chronic obstructive pulmonary disease, and smoking, but also demonstrated that CEA type was not an independent predictor of mortality. The 1-year freedom from recurrent stenosis >50% was lower for ECEA (88.8% vs 94.3%, P < .001). However, ECEA and CCEA both had a very high rate of freedom from reoperation at 1 year (99.5% vs 99.6%; P = .67).

CONCLUSIONS

ECEA and CCEA appear to provide similar freedom from neurologic morbidity, death, and reintervention. ECEA was associated with significantly shorter procedure times. Furthermore, ECEA obviates the expenses, including increased operative time, associated with use of a patch in CCEA, and a shunt, more often used in CCEA in this database. These potential benefits may be reduced by a slightly greater requirement for early return to the operating room for bleeding.