Correlation of carotid artery stump pressure and neurologic changes during 474 carotid endarterectomies performed in awake patients

Bypass and other modified reconstruction techniques for 'challenging' carotid cases: A comparison with conventional endarterectomy

OBJECTIVE

Standard carotid endarterectomy (CEA) is usually performed with patch closure or eversion. However, sometimes a 'modified' carotid artery revascularization (MCAR) technique is required if the lesion is complex, extended and anatomically or technically challenging. MCAR is defined as carotid artery bypass; otherwise, it is the combination of common carotid artery (CCA) primary suture or patch angioplasty, associated with internal carotid artery (ICA) patch closure or eversion. The aim of this study was to evaluate the outcomes of MCAR during complex carotid procedures, comparing them with standard CEA.

METHODS

A retrospective analysis of asymptomatic patients who underwent CEA during a 16-year period (June 2005 to June 2021) was performed. Patients were divided into three different groups: ECEA (eversion CEA), PCEA (CEA with patch angioplasty) and MCAR. Primary endpoints were relevant neurological complication rate (RNCR), death within 30 days, freedom from ipsilateral stroke, reintervention rates and freedom from carotid artery restenosis.

RESULTS

A total of 1,752 patients were included (ECEA: 699; PCEA: 948; MCAR: 105) in the study. Patients treated with MCAR were significantly older and had a higher SVS score for arterial hypertension compared with ECEA and PCEA groups. A long plaque in the CCA was the most common indication for MCAR (40.1%); inadequate distal plaque-end or distal dissection (25.7%) was the second most prevalent indication. Overall perioperative RNCR, defined as minor and major stroke, was 0.7% (ECEA: 0.4%; PCEA: 0.7%; MCAR: 1.9%; p = 0.22), without any significant difference among the three groups. However, patients treated with MCAR had a significantly higher rate of global central neurological complications (defined as transient ischaemic attack, minor stroke and major stroke) than the other cohorts (ECEA: 0.7%; PCEA: 1.2%; MCAR: 3.8%; p = 0.02). One patient (0.05%) died perioperatively of a major cerebral infarction. Long-term follow-up (66.7 ± 43.9) showed a significantly lower rate of freedom from ipsilateral stroke for the MCAR group (96.8%) compared with ECEA and PCEA groups (99.8% and 98.9%, respectively, p = 0.03). Similar reintervention rates (ECEA: 2.7%; PCEA: 3.3%; MCAR: 3.8%; p = 0.74) and freedom from carotid restenosis rates (ECEA: 1.3%; PCEA: 2.6%; MCAR: 1.9%; p = 0.16) were observed.

CONCLUSIONS

Patients who underwent ICA revascularization with MCAR showed risks of perioperative death, major or minor stroke (<2%), reintervention rates and carotid restenosis rates that are comparable with PCEA or ECEA groups. Nevertheless, the MCAR group showed a significantly higher rate of global central neurological complications (considering together TIA, minor stroke and major stroke) than patients treated with standard CEA. MCAR techniques appear to be effective alternatives to standard CEAs, with an acceptable surgical risk. However, these should be performed mainly in selected cases, for example, in complex anatomy (detected in a non-negligible percentage of patients by preoperative imaging), or in the case of unexpected intraoperative technical issues.

Optimal cutoff value of carotid stump pressure for determining the need for a carotid shunt in carotid artery endarterectomy

OBJECTIVE

This study was conducted to identify the diagnostic value of carotid stump pressure for determining the need for a carotid artery shunt in patients undergoing carotid artery endarterectomy.

MATERIALS AND METHODS

Carotid stump pressure was prospectively measured in all carotid artery endarterectomies performed under local anesthesia between January 2020 and April 2022. The shunt was selectively used when neurological symptoms appeared after carotid cross-clamping. Carotid stump pressure was compared between patients who needed shunting and those who did not. Demographic and clinical characteristics, hematological and biochemical parameters, and carotid stump pressure of the patients with and without shunts were statistically compared. To determine the optimal cutoff value and diagnostic performance of carotid stump pressure for identifying the patients who need a shunt, receiver operating characteristic analysis was performed.

RESULTS

Overall, 102 patients (61 men and 41 women) who underwent carotid artery endarterectomy under local anesthesia were included, with an age range of 51-88 years. A carotid artery shunt was used in 16 (8 men and 8 women) patients. The carotid stump pressure values of the patients with a shunt were lower than those without a shunt (median (min-max): 42 (20-55) vs 51 (20-104), p < 0.0006). In the receiver operating characteristic curve analysis performed to determine the need for a shunt, the optimal cutoff value of carotid stump pressure was ≤48 mmHg, sensitivity was 93.8%, and specificity was 61.6% (area under the curve: 0.773, p < 0.0001).

CONCLUSION

Carotid stump pressure has sufficient diagnostic power to determine the need for a shunt, but it cannot be used alone in the clinical setting. Instead, it can be used in combination with other neurological monitoring methods.

A systematic review & meta-analysis on perioperative cerebral and hemodynamic monitoring methods during carotid endarterectomy

OBJECTIVE

To compare outcomes between different strategies of perioperative cerebral and hemodynamic monitoring during carotid endarterectomy.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL databases were searched.

METHODS

This review was performed according to the PRISMA guidelines and prospectively registered in the international prospective register of systematic reviews (CRD42021241891). The GRADE approach was used to describe the methodological quality of the studies and certainty of the evidence. The primary outcome was 30-day stroke rate. Secondary outcomes measures are 30-day ipsilateral stroke, 30-day mortality, shunt rate and complication rates.

RESULTS

The search identified 3 460 articles. Seventeen RCTs, three prospective observational studies and seven registries were included, reporting on 236 983 patients. The overall pooled 30-day stroke rate is 1.8% (95% CI 1.4 - 2.2%), ranging from 0 - 12.6%. In RCT's the pooled 30-day stroke rate is 2.7% (95% CI 1.6 - 3.7%) compared to 1.3% (95%CI 0.8 - 1.8%) in the registries. The overall stroke risk decreased from 3.7% before the year 2000 to 1.6% after 2000. No significant differences could be identified between different monitoring and shunting strategies, although a trend to higher stroke rates in routine no shunting arms of RCTs was observed. Overall 30-day mortality, myocardial infarction and nerve injury rates are 0.6% (95%CI 0.4 - 0.8), 0.8% (95%CI 0.6-1.0) and 1.3% (95%CI 0.4-2.2), respectively.

CONCLUSIONS

No significant differences between the compared shunting and monitoring strategies are found. However, routine no shunting is not recommended. The available data is too limited to prefer one method of neuromonitoring over another method when selective shunting is applied.

The Effect of Severe Contralateral Carotid Stenosis or Occlusion on Early Outcomes after Carotid Endarterectomy

BACKGROUND: Stenosis of the carotid arteries, as a consequence of atherosclerosis is the most common cause of cerebrovascular insult (CVI). Severe (>70%) contralateral stenosis or occlusion (SCSO) of the carotid artery may represent an additional pre-operative risk factor  for neurologic incidents.             AIM: The aim of this study was to confirm and compare early perioperative results (0-30 days) of carotid endarterectomy (CEA) in patients with and without SCSO.                 PATIENT AND METHODS: In our retrospective-prospective study, we analysed the results of 273 CEA, divided into two groups based on the presence of significant contralateral stenosis or occlusion (non-SCSO and SCSO groups)             RESULTS: 273 CEA’s were performed, divided into two groups: SCSO groups 40 (14.7%) and non-SCSO group 233 (85.3%). Between the two groups, a statistically significant difference between patients was found (54.1% compared to 87.5%; p<0.0005), CEA with patch angioplasty (25.3% compared to 52.5%; p=0.001),  and CEA with the use of a shunt (3.9% compared to 35%; p<0.0005) in favour of the SCSO group. There was no statistically significant difference (SCSO was not identified as a risk factor) for any type of stroke or mortality. Logistically regression confirmed SCSO to be an independent predictor of 30-day mortality (OR 21.58; 95% CI  1.27-36.3; p= 0.033) and any type of stroke or mortality (OR 9.27; 95% CI  1.61-53.22; p= 0.012). SCSO was not a predictor of any type of stroke within 30 days. Predictors of any type of stroke was dyslipidemia (OR 0.12, 95% CI  0.02-0.76; p= 0.024).             CONCLUSIONS: There was no statistically significant difference in the incidence of early (30 day) perioperative complications between the analysed groups. The percentage of perioperative complications remains within the accepted parameters, and thus, SCSO should not be qualified as a significant risk factor for CEA. We are of the opinion that CEA remains a safe and acceptable options for patients with SCSO, and SCSO should not be a reason for preferential use of carotid stenting.

Completion Arteriogram Following Carotid Endarterectomy Yields Lower Perioperative Stroke Rate

Introduction: Completion imaging following carotid endarterectomy (CEA) remains controversial. We present our experience performing routine completion arteriography (CA). Methods: A retrospective review of our prospectively maintained institutional database was performed for patients undergoing isolated CEA. Results: 1439 isolated CEAs with CA were performed on 1297 patients. CEA was for asymptomatic lesions in 70% (1003) of cases. There were no complications related to arteriography. An abnormal arteriogram documented significant abnormalities in the internal carotid artery (ICA) and prompted revision in 1.7% (24/1439) of cases: 20 unsatisfactory distal endpoints of the endarterectomy (12 residual stenoses, 7 intimal flaps, and 1 dissection), 3 kinks or stenoses within the body of the patch, and 1 thrombus. Of the 20 distal endpoint lesions, stent deployment was used in 17 cases and patch revision in 3 cases. The other 4 cases were treated by patch angioplasty (3) or thrombectomy (1). None suffered a perioperative stroke. The overall 30-day stroke, death, and combined stroke/death rate for the 1439 patients in our series was 1.5% (22), .5% (7), and 1.9% (27), respectively. The combined stroke/death rate for asymptomatic lesions was 1.1% (11/1003) and for symptomatic lesions was 2.5% (11/436). Of the 22 strokes in the entire series (all with normal CA), 15 were non-hemorrhagic strokes ipsilateral to the CEA; 14 were confirmed to have widely patent endarterectomy sites by CT-A (13) or re-exploration and repeat arteriography (1). The occluded site was re-explored and underwent thrombectomy, but no technical problems were identified. The remaining strokes were hemorrhagic (4 reperfusion syndrome and 1 surgical site bleeding) or contralateral to the CEA (2). Conclusion: Although not all patients in this series who underwent intraoperative revision due to abnormal CA might have suffered a stroke, performing this simple and safe study may have halved our overall perioperative stroke rate from 3.2% to 1.5%.

Intraoperative Cerebral Monitoring During Carotid Surgery: A Narrative Review

BACKGROUND

Intra-operative neurological monitoring (IONM) during carotid endarterectomy (CEA) aims to reduce neurological morbidity of surgery.

OBJECTIVE

This narrative review analyses the role and results of different methods of IONM.

METHODS

review articles on PUBMED and Cochrane Library, by searching key words related to IONM and CEA, from 2000 up to date.

RESULTS

regional anesthesia in some centers represents the "gold standard". The most often used alternative techniques are: stump pressure, electroencephalogram, somatosensory evoked potentials, transcranical doppler ultrasound, near infrared spectroscopy and routine shunting. Every technique shows limitations. Regional anesthesia can make difficult prompt intubation when needed. Stump pressure shows a wide operative range. Electroencephalogram is unable to detect ischemia in sub-cortical regions of the brain. Somatosensory evoked potentials certainly demonstrate the presence of cerebral ischemia, but are no more specific or sensitive than the electroencephalogram. Transcranical doppler monitoring is undoubtedly operator-dependent and suffers from the limitations that the probe has to be placed relatively near to the surgical site and may impede the operator, especially if it needs constant adjustments; moreover, an acoustic window may not be found in 10% -20% of the subjects. Near infrared spectroscopy appears to have a high negative predictive value for cerebral ischemia, but has a poor positive predictive value and low specificity, because predominantly estimates venous oxygenation as this makes up about 80% of cerebral blood volume. The data on the use of Routine Shunting (RS) from RCTs are limited.

CONCLUSIONS

currently, with no clear consensus on monitoring technique, choice should be guided by local expertise and complication rates. With reflection, best practice may dictate that a standard technique is selected as suggested above and this remains the default position for individual practice. Nevertheless, current techniques for monitoring cerebral perfusion during CEA are associated with false negative and false positive resulting in inappropriate shunt insertion.

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.

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.

Carotid Endarterectomy with Modified Eversion Technique: Results of a Single Center

BACKGROUND

Carotid endarterectomy (CEA) has a wide range of approaches based on personal expertise and preference. We evaluated our outcome with CEA with modified eversion technique (meCEA) under local anesthesia and whether the surgeon's experience could influence it.

METHODS

at our Institution, 837 patients underwent CEA across 8 years. Although the surgical technique was standardized, 2 groups were considered further: meCEA performed by a single Senior Operator (Group A) and meCEA performed by 4 young Consultants (Group B).

RESULTS

A selective shunting policy was needed in 5.1%, together with general anesthesia. Overall operative time was 63.9 ± 15.1 minutes (61.4 ± 12.5 and 66 ± 16.9 minutes in Group A and Group B respectively; P < 0.001) and cross-clamp time 19.3 ± 2.9 minutes (19.0 ± 3.2 vs. 19.5 ± 2.8, P = 0.009). At 30 days, 0.7% TIA and 0.8% strokes were recorded. No differences (p = N.S.) between the 2 study groups in terms of postoperative neurological complications, with postoperative ipsilateral strokes always < 1%. At a median imaging follow-up of 22.5 months, the overall percentage of restenosis was 3.7%, with no difference between the 2 groups (P = 0.954). Twenty-two patients (2.6%) underwent reintervention for significant restenosis, and none of them had an ipsilateral stroke or TIA. Freedom from reintervention for restenosis at 24 months was 97.9% in Group A and 95.9% in Group B, with no between-group difference (P = 0.14). At the median survival follow-up of 37 months, the overall survival rate at 24 months was 97.9%in Group A, and 97.9% in Group B, with no between-group difference (P = 0.070).

CONCLUSIONS

In our experience, CEA with a modified technique is safe and achieves comparable outcomes to those of other established techniques. The reported short cross-clamp time, also in less experienced hands, is an additional strength.

Neuromonitoring during general anesthesia in non-neurologic surgery

Cerebral complications are common in perioperative settings even in non-neurosurgical procedures. These include postoperative cognitive dysfunction or delirium as well as cerebrovascular accidents. During surgery, it is essential to ensure an adequate degree of sedation and analgesia, and at the same time, to provide hemodynamic and respiratory stability in order to minimize neurological complications. In this context, the role of neuromonitoring in the operating room is gaining interest, even in the non-neurolosurgical population. The use of multimodal neuromonitoring can potentially reduce the occurrence of adverse effects during and after surgery, and optimize the administration of anesthetic drugs. In addition to the traditional focus on monitoring hemodynamic and respiratory systems during general anesthesia, the ability to constantly monitor the activity and maintenance of brain homeostasis, creating evidence-based protocols, should also become part of the standard of care: in this challenge, neuromonitoring comes to our aid. In this review, we aim to describe the role of the main types of noninvasive neuromonitoring such as those based on electroencephalography (EEG) waves (EEG, Entropy module, Bispectral Index, Narcotrend Monitor), near-infrared spectroscopy (NIRS) based on noninvasive measurement of cerebral regional oxygenation, and Transcranial Doppler used in the perioperative settings in non-neurosurgical intervention. We also describe the advantages, disadvantage, and limitation of each monitoring technique.

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.

Identifying a Safe Carotid Stump Pressure Threshold for Selective Shunting During Carotid Endarterectomy

BACKGROUND

There is no current consensus on the best criteria for selective shunting during carotid endarterectomy (CEA). The choice of continuous neurologic assessment during awake CEA, intraoperative electroencephalogram, or carotid stump pressure monitoring as the basis for shunt placement is primarily dependent on surgeon preference. Our goal is to define a safe stump pressure threshold as a guide for selective shunting.

METHODS

The study is a single-surgeon retrospective review of consecutive patients who underwent CEA under general anesthesia with selective shunting based on intraoperative stump pressure measurements from 2001 to 2019. Demographic and periprocedural variables were analyzed using standard statistical techniques.

RESULTS

Among 399 patients, 68% were male with a mean age of 70. One-third of the patients were symptomatic, with amaurosis fugax in 12%, transient ischemic attack in 7%, and stroke in 16%. In total, 60 (15%) patients underwent shunting: 34 for a confirmed preoperative acute ischemic stroke, 22 for a stump pressure <30 mm Hg, and 4 for other indications. Overall 30-day death, ischemic ipsilateral stroke, myocardial infarction, and cranial nerve palsy rates were 0.5%, 0.8%, 1.8%, and 1.0%, respectively. No strokes occurred due to hypoperfusion, and all stroke symptoms resolved prior to discharge with a mean length of stay of 1.6 days.

CONCLUSIONS

This is one of the largest contemporary series of CEA using a 30 mm Hg threshold for selective shunting that demonstrated exceedingly low 30-day death and stroke events. Intraoperative carotid stump pressure measurements are a useful guide for selective shunting and reduction in perioperative stroke complications after CEA.

Association of biomarker S100B and cerebral oximetry with neurological changes during carotid endarterectomy performed in awake patients

Background: This study attempted to correlate neurological symptoms in awake patients undergoing carotid endarterectomy (CEA) under local anaesthesia (LA) with serum concentration of S100B protein and measurement of cerebral oximetry with near-infrared spectroscopy (NIRS). Patients and methods: A total of 64 consecutive CEAs in 60 patients operated under LA during an 18-month period were prospectively evaluated. A cerebral oximeter was used to measure cerebral oxygen saturation (rSO₂) before and after cross-clamping along with serum concentration of the S100B protein. Selective shunting was performed when neurological changes occurred, regardless of NIRS. Neurological deterioration occurred (neurological symptoms group) in 7 (10.9 %) operations. In 57 (89.1 %) operations, the patients were neurologically stable (no neurological symptoms group). Results: The neurological symptoms that occurred after clamping correlated with an increase in the serum level of S100B (P = .040). The cut-off of 22.5 % of S100B increase was determined to be optimal for identifying patients with neurological symptoms. There was no correlation between rSO₂ decline and neurological symptoms (P = .675). Two (3.1 %) perioperative strokes occurred. Conclusions: We found a correlation between neurological symptoms and serum S100B protein increase. However, because of the long evaluation time of serum S100B, this monitoring technique cannot be performed during CEA.

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.

Near-infrared spectroscopy as a predictor of cerebral ischaemia during carotid endarterectomy in awake patients

Objectives

The aim of our study was to evaluate the near-infrared spectroscopy monitoring system to detect cerebral ischaemia, find indications for selective shunting during carotid endarterectomy and compare it with an internal carotid artery stump pressure monitoring technique in patients operated under local anaesthesia.

Methods

During January 2015 and November 2018, 131 patients undergoing carotid endarterectomy under local anaesthesia were prospectively included in the study. Near-infrared spectroscopy as intraoperative monitoring was applied and compared with stump pressure.

Results

Carotid endarterectomy was performed successfully in 106 patients operated under local anaesthesia. Meanwhile, 25 patients developed neurological changes (motor or consciousness impairment, weakness of extremities, cognitive decline) during clamping, and all of them received a shunt. ΔrSO2, stump pressure and rSO2 (–11 ± 8%, 31 ± 6mmHg, 58 ± 11) values were smaller in the group of shunted subjects versus non-shunted group subjects (–2 ± 5%, 61 ± 17 mmHg, 64 ± 8) after 1 min of internal carotid artery clamping ( p < 0.05). Statistical analysis showed a sensitivity of 90% (95% CI: 0.85–0.95) and a specificity of 70% (95% CI: 0.62–0.78) for a ≥10% drop in ΔrSO2 to predict ischaemia symptoms during carotid clamping. Using stump pressure with a cut-off value of ≤40 mmHg for predicting symptoms, the sensitivity was 82% and specificity 54%.

Conclusions

Near-infrared spectroscopy is a suitable non-invasive cerebral oxygenation monitoring method during carotid endarterectomy. A 10% decrease of ΔrSO2 had a good correlation with clinical cerebral ischaemia signs and matched well with the stump pressure cut-off value of ≤40 mmHg. There is a possibility of near-infrared spectroscopy to replace stump pressure in cerebral oxygenation monitoring during carotid endarterectomy. However, we need larger prospective multicentre studies to identify the optimal threshold for shunt requirement.

Persistent Hypoglossal Artery: Challenges Associated With Carotid Revascularization

Anomalous connections between the anterior and posterior cranial circulation are rare embryologic entities. A persistent hypoglossal artery has a reported incidence of 0.03% to 0.09% and has been linked to intracranial aneurysms, atherosclerosis, and posterior circulation ischemia. Identification of this anomaly is essential prior to carotid artery revascularization given the technical challenges and added risks with intervention. We report a case of an 80-year-old female with progression of carotid stenosis in the setting of a persistent hypoglossal artery. We provide a review of the literature and discuss the technical challenges of carotid revascularization in this patient.

Low carotid stump pressure as a predictor for ischemic symptoms and as a marker for compromised cerebral reserve in octogenarians undergoing carotid endarterectomy

BACKGROUND

Carotid artery occlusive disease can cause stroke by embolization, thrombosis, and hypoperfusion. The majority of strokes secondary to cervical carotid atherosclerosis are believed to be of embolic etiology. However, cerebral hypoperfusion could be an important factor in perioperative stroke. We retrospectively reviewed the stump pressure (SP) of carotid endarterectomy (CEA) of patients at Pennsylvania Hospital to identify whether physiologic perfusion differences account for differences in perioperative stroke rates, particularly in octogenarians.

METHODS

We conducted a retrospective review of our prospectively maintained database for CEA performed between 1992 and 2015. SP was measured and recorded for 1190 patients. A low SP was defined as systolic pressure <50 mm Hg. Shunts were used only for patients under general anesthesia with SP <50 mm Hg, for awake patients with neurologic changes with carotid clamping, and in some patients with recent stroke.

RESULTS

Symptomatic patients were more likely to have SP <50 mm Hg compared with asymptomatic patients (35.6% vs 26.2%; P = .0015). Patients having SP <50 mm Hg had a higher postoperative stroke rate compared with patients with SP >50 mm Hg (2.9% vs 0.9%; P = .0174). Octogenarians were more likely to have a lower SP compared with patients younger than 80 years (35.7% vs 27.7%; P = .0328). Symptomatic patients with low SP were at highest risk for perioperative stroke (6.4% vs 1.2%; P = .001) compared with patients without these factors.

CONCLUSIONS

SP is a marker for decreased cerebrovascular reserve and along with symptomatic status identifies those at highest risk for periprocedural stroke with CEA. Whereas patients older than 80 years may benefit from carotid intervention, they are likely to be at somewhat elevated stroke risk because of higher prevalence of low SP, and shunting does not eliminate this risk.

Cerebral Neuromonitoring during Carotid Endarterectomy and Impact of Contralateral Internal Carotid Occlusion

BACKGROUND

The aim of this study was to identify the reliability of carotid artery stump pressure (SP) in predicting the neurologic changes and correlation with contralateral internal carotid artery (ICA) occlusion in patients undergoing eversion carotid endarterectomy (CEA). The optimal method for monitoring cerebral perfusion during CEA, performed under either local or general anesthesia, is still controversial.

METHODS

We prospectively analyzed 118 consecutive patients undergoing eversion CEA under local anesthesia. We had 78 symptomatic (66%) and 40 asymptomatic patients (33.9%). Selective shunting was performed in patients who developed neurologic changes after carotid clamping regardless of SP. Correlation of preoperative symptom status, a degree of stenosis, status of contralateral ICA, arterial blood pressure, SP value, and the intraoperative need for shunting due to neurologic changes was evaluated for both groups: shunted and nonshunted.

RESULTS

Selective shunting was performed in 12 patients (10%). There was no significant difference among the groups regarding the demographic characteristics. Mean carotid clamping time was 14.57 minutes. We had no perioperative mortality, stroke, or myocardial infarction. None of the patients required conversion to general anesthesia. We found a mean SP of 31 mm Hg as a reliable threshold for shunting (P < .001; sensitivity 92.3%; specificity 91.3%). Contralateral carotid occlusion was correlated with the significantly lower SP (27 ± 13 mm Hg; P = .001) and the higher need for shunt (50%).

CONCLUSIONS

SP measurement is a reliable and simple method for monitoring the collateral cerebral perfusion and can predict the need for shunting during CEA. Patients with the contralateral ICA occlusion showed significantly lower SP, although it did not have impact on the outcome.

Anesthetic Considerations for Carotid Endarterectomy: A Postgraduate Educational Review

Carotid endarterectomy (CEA) has shown a significant benefit in preventing ipsilateral stroke when it is compared to conservative management. Surgical morbidity and mortality must be kept to a minimum to achieve this benefit. Neurological status of the CEA patients can be monitored easily during regional anesthesia depending on the awake testing (neurocognitive assessment) method of the CEA patients. In addition, specific parameters can help us to monitor and to predict the neurological status of the CEA patients during the procedures such as regional cerebral oxygen saturation (rSO₂) and middle cerebral artery velocity (MCAv) changes. We conducted a computerized literature search involving humans, published in English until December 2017, and indexed through Medical Databases; MEDLINE/PubMed, EMBASE, and Web of Science. We reviewed articles performed for prospective and other types of studies related to CEA procedures and techniques which can predict patient's status during the procedure. Searching relevant articles and discussing the results to allow meaningful rate comparison, and to conclude a result view which benefits the CEA patients and the medical staff during the CEA procedures. In total, studies observed cerebral rSO₂ and MCAv have significant value during CEA procedures. Patients with neurological symptoms during the procedures showed changes of cerebral rSO₂ and MCAv more than the patients without neurological symptoms. Mentioned parameters (cerebral rSO₂ and MCAv) showed significant increasing right after the procedure. Mostly, CEA surgeries under local anesthesia were observed, for monitoring patients' consciousness status and comparing it to patients who undergo general anesthesia, to view the reliability of these techniques during CEA procedures, and to predict and avoid intraoperative neurological symptoms.

The role of stump pressure and cerebral oximetry in predicting ischaemic brain damage during carotid endarterectomy

Objective is to compare the predictive value of stump pressure (SP) and cerebral oximetry (rSO2) levels in the evaluation of ischaemic injury of the cerebrum during clamping of the carotid artery (CCA) without temporary shunt (TS). Methods We included 84 patients with an asymptomatic stenosis (>70%) of the internal carotid artery (ICA) who underwent carotid endarterectomy (CEA) under GA. Cerebral ischaemic tolerance (CIT) was determined on the basis of SP, rSO2 and ∆rSO2 (↓rSO2 from baseline) during CCA. The levels of S100 protein (S100) and neuron-specific enolase (NSE) were measured on each stage of the study. MRI was performed for all patients. Results There were no perioperative strokes and myocardial infarctions during the study. Temporary shutdown of blood flow in CAs during CEA is accompanied by a significant elevation of S100, NSE concentration with their subsequent restoration (three days after surgery). ROC analysis showed that none of the methods for CIT assessment (SP, rSO2 and ∆rSO2) was a valuable predictor of cerebral damage during CEA. Conclusion SP with a threshold value of ≤40 mmHg has an average quality of prediction (AUC = 63). ∆rSO2 of ≥20% and a threshold value of rSO2 ≤ 40% have an unsatisfactory quality of prediction (AUC < 60).

Combined Stump Pressure and Oximetry for Shunt Use During Carotid Endarterectomy

BACKGROUND

Cross-clamp ischemia during carotid endarterectomy can be prevented with carotid bypass shunts in vulnerable patients identified by cerebral monitoring for ischemia. We compared transcranial cerebral oximetry (TCO) with carotid stump pressure measurements for selective shunt use.

METHODS

We prospectively collected data on 300 consecutive patients operated on under general anesthesia between 2009 and 2016. Shunts were inserted for a 10% or greater drop in cerebral saturations and/or a mean stump pressure less than 40 mmHg.

RESULTS

Seventy-five patients, 25% of the study population, were shunted. The indication was a combined desaturation and stump pressure in 38 (50% of the shunted group), desaturation alone in 11 patients (15%), and a low stump pressure alone in 26 patients (35%). There were no significant differences in baseline characteristics between those patients who were or were not shunted, except angiographic collateral blood supply, which was more commonly identified in patients who were not shunted. A watershed infarct occurred in just one patient with borderline TCO and stump pressure measurements in whom a shunt was not used.

CONCLUSIONS

There was poor concordance between TCO and stump pressures, but using both in determining the need for shunt use almost eliminated cross-clamp ischemia in this series of 300 carotid endarterectomy patients.

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.

Anesthetic approaches in carotid body tumor surgery

OBJECTIVE

Carotid body tumors (CBT) are benign tumors that originate from neural non-chromaffin cells that are typically localized near carotid bifurcation. Surgical removal of the tumor is the most appropriate treatment. General anesthesia is preferred anesthetic technique for CBT surgery. Basic elements of anesthetic management are protection of hemodynamic stability and maintaining cerebral perfusion pressure (CPP). The aim of this study was to evaluate anesthetic management of CBT surgery and present the literature knowledge.

METHODS

The study included 10 consecutive patients with diagnosis of CBT who underwent surgery at Antalya Training and Research Hospital, in Antalya, Turkey, between 2013 and 2016. Preoperative demographic details; comorbidities; side of surgical site; duration of operation; length of intensive care unit (ICU) and hospital stay; change of intraoperative blood pressure; use of inotropic drugs, blood products, and analgesics; postoperative visual analogue scale (VAS) pain score; and complications were recorded.

RESULTS

According to Shamblin classification, 3 tumors were type I and the remaining 7 were type II. Tumors were located on right side in 6 patients, and on left in 4. Blood loss sufficient to require transfusion was observed in 1 patient. Average intraoperative blood loss was 287±68 mL. Tachycardia and hypertension were observed in 1 patient; bradycardia and hypotension were seen in 4 patients. Infusion for inotropic support was administered to 1 patient. Mean duration of operation was 109±20 minutes. Mean VAS score was 4±1, mean ICU tramadol consumption was 80±25 mg. Duration of stay in ICU and hospital were 2.4±1.1 hours and 3.8±0.7 days, respectively. Mortality and neurological complications were not seen in postoperative period.

CONCLUSION

CBT surgery requires close and complex anesthesia management. Protection of hemodynamic stability against sudden hemodynamic changes, monitoring, and maintaining CPP are the most important aspects of anesthetic management.

A Cost Analysis of Regional Versus General Anesthesia for Carotid Endarterectomy

BACKGROUND

Medical care in the United States has evolved into a more cost-conscious value-based health care system that necessitates a comparison of costs when there are alternative interventions considered to be acceptable in the treatment of a disease. This study compares the cost differences between regional anesthesia (RA) and general anesthesia (GA) for carotid endarterectomy (CEA).

METHODS

Data from 346 consecutive patients who underwent CEA between January 2012 and September 2014 were retrospectively reviewed for the type of anesthesia used, outcomes data, and cost variables. Overall hospital day costs were compared between RA and GA. Medians and interquartile ranges were compared using Wilcoxon-Mann-Whitney test. A P < 0.05 was considered statistically significant using 2-sided tests.

RESULTS

Median overall costs for GA were significantly higher than median costs for RA (medians [with interquartile ranges], $10,140 [$7,158-$12,658] versus $7,122 [$5,072-$8,511], P < 0.001). Median total operative time for GA was significantly longer than median time for RA (168 [144-188] versus 134 [115-147] min, P < 0.001). Median in-hospital length of stay (LOS) for GA was significantly longer compared with RA (2.0 vs 1.2 days, P < 0.001). Patients who received GA were also more likely to be admitted to the intensive care unit.

CONCLUSIONS

Decreased cost, operating room expenses, postoperative resources, and overall LOS were observed for individuals who underwent RA for CEA as compared with GA. In summary, RA is more cost-effective and should be the optimal choice when clinically appropriate.

Monitoring cerebral ischemia during carotid endarterectomy and stenting

Current therapy for carotid stenosis mainly includes carotid endarterectomy and endovascular stenting, which may incur procedure-related cerebral ischemia. Several methods have been employed for monitoring cerebral ischemia during surgery, such as awake neurocognitive assessment, electroencephalography, evoked potentials, transcranial Doppler, carotid stump pressure, and near infrared spectroscopy. However, there is no consensus on the gold standard or the method that is superior to others at present. Keeping patient awake for real time neurocognitive assessment is effective and essential; however, not every surgeon adopts it. In patients under general anesthesia, cerebral ischemia monitoring has to rely on non-awake technologies. The advantageous and disadvantageous properties of each monitoring method are reviewed.

A Prospective Nonrandomized Study on Carotid Surgery Performed under General Anesthesia without Intraoperative Cerebral Monitoring

BACKGROUND

The purpose of this study was to assess our experience of carotid surgery habitually performed under general anesthesia without intraoperative intracerebral monitoring, and following a pre-established perioperative protocol, which includes extensive use of an intraoperative shunt (IOS).

METHODS

This study included 311 consecutive carotid operations performed over 32 months. This patient cohort represents 14% of our total experience in carotid surgery (2219 operations, major stroke/mortality rate: 1.4%). The IOS was inserted routinely in the presence of intraoperative blood pressure instability during cross-clamping and when the predictable clamping time might have exceeded 20 minutes. A moderate and stable hypertension was maintained throughout surgery without IOS.

RESULTS

Overall, 120 (38.6%) endarterectomies were performed with primary closure, 73 (23.5%) with eversion technique, 113 (36.3%) with patch angioplasty, and 5 (1.6%) with other techniques. Out of 113 patch angioplasties, 111 (98.2%) were performed with an IOS. This was utilized in only 3 cases of direct carotid reconstructions or other carotid endarterectomy techniques (1.5%). Overall, the IOS placement rate was 36.7%. Postoperatively, 2 major strokes (.64%), 2 minor strokes (.64%), 4 hyperperfusion syndromes (1.3%), and no mortality were recorded. No cases of cross-clamp ischemia/shunt-related perioperative strokes were observed.

CONCLUSIONS

The low perioperative stroke rate reported in this prospective study proves the advantages of wide use of IOS during carotid surgery. This coupled with a large experience in carotid surgery and close monitoring and support of blood pressure, are the major determinants of these results that demonstrate the low risk of shunt-related complications for surgeons who regularly utilize an IOS.

Carotid Revascularization: An Update

Symptomatic extracranial internal carotid artery stenosis poses a high short-time risk of ischemic cerebral stroke, as high as 20% to 30% in the first three months. Timely performed carotid endarterectomy (CEA) has been shown to be highly effective in reducing this risk although, in recent years, there has been great interest in replacing this procedure with less invasive carotid angioplasty and stenting (CAS). In this update we review recent studies and provide recommendations regarding the indications, methods and timing of surgical intervention as well as the anaesthetic management of CEA, and we report on recently published randomized controlled trials comparing CEA to CAS. We also provide recommendations regarding the sometime neglected but important medical management of patients undergoing carotid intervention, including antithrombotic and antihypertension therapy, lipid lowering agents, assistance with smoking cessation, and diabetes control.

Preoperative digital carotid compression as a predictor of the need for shunting during carotid endarterectomy

This study prospectively attempted to assess the need for shunting by preoperative digital compression of the proximal common carotid artery and correlated these findings with intraoperative assessment while performing carotid endarterectomy under local anaesthesia. Preoperative digital compression is highly predictive of the need for shunting intra-operatively and can be used as a valuable test in carefully chosen patients. This may help in decreasing the need for advanced neurological monitoring during carotid endarterectomy.

Discrepancy between voluntary movement and motor-evoked potentials in evaluation of motor function during clipping of anterior circulation aneurysms

BACKGROUND

Various modalities have been used to confirm the blood flow through parent arteries or surrounding perforating arteries during surgical aneurysm clipping, including motor-evoked potentials (MEPs), Doppler ultrasound, and indocyanine green videoangiography. Nonetheless, contralateral hemiparesis due to arterial blood flow insufficiency may arise because of false-positive or false-negative errors. By performing controlled intraoperative awakening during aneurysm clipping, we compared patients' voluntary movements with simultaneous MEP.

METHODS

Four patients with anterior choroidal artery aneurysms and one patient with a dorsal internal carotid artery aneurysm were included in this study. MEP and intraoperative voluntary movements under awake craniotomy were assessed simultaneously during and after the clipping procedure.

RESULTS

Aneurysms were safely and successfully clipped in all patients, with no evidence of postoperative neurological deficits. Voluntary movements and MEP findings did not differ from the control state in three patients. In the other two patients, we observed a discrepancy between MEP amplitudes and voluntary movements. In one patient, deterioration and subsequent improvement in voluntary movements were preceded by MEP amplitude reduction during clipping. In the other patient, MEP amplitude did not change although voluntary movement deteriorated during temporary occlusion of the internal carotid artery.

CONCLUSIONS

Intraoperative neurological assessment during aneurysmal clipping under awake craniotomy is feasible and safe, and should be valuable for the assessment of ischemia, especially in the anterior choroidal artery. From a neurophysiologic viewpoint, MEP may be insufficiently sensitive for evaluating voluntary movement under ischemia.

Preoperative magnetic resonance angiography as a predictive test for cerebral ischemia during carotid endarterectomy

BACKGROUND

To evaluate whether the preoperative magnetic resonance angiography (MRA) can predict the risk of cerebral ischemia associated with the carotid endarterectomy (CEA).

METHODS

Between January 2004 and December 2010, 382 consecutive patients (mean age: 56.6 years; range: 45-78 years) were identified to have undergone preoperative MRA and the CEA under regional anesthesia. It was determined that the patient needs shunting during the CEA by intraoperative monitoring of patient's neurology. All patients were divided into two subgroups: shunt group or no-shunt group. Imaging findings on preoperative MRA were correlated to shunting using univariate and multivariate logistic regression analyses combined with patient's demographic and clinical features to identify predictors of cerebral ischemia during the CEA.

RESULTS

In 37 of 382 CEA cases (9.7%), shunting had been performed intraoperatively because the patient had a neurologic deficit. At multivariate analysis, preoperative MRA findings such as the absence of patent communicating arteries (odds ratio [OR], 5.56; 95% confidence interval [CI], 3.05-9.69; p = 0.013) and the increase of intracranial arteries which were not patent in the contralateral hemisphere (OR, 4.277; 95% CI, 2.575 to 7.104; p < 0.0001) were significantly associated with shunting.

CONCLUSIONS

Preoperative MRA is valuable when predicting cerebral ischemia leading to an inevitable shunting during CEA. Therefore, if there are preoperative MRA findings such as multiple occlusive intracranial arteries in the contralateral hemisphere or the absence of patent communicating arteries, it is recommended that CEA be performed under general anesthesia with routine shunting to avoid a serious shunt-related complication.

Selective shunt during carotid endarterectomy using routine awake test with respect to a lower shunt rate

PURPOSE

To evaluate shunt rate and discuss the resultsrelated to selective shunt placement during carotid endarterectomy (CEA) using routine awake test.

METHODS

Patients with CEA from 2007 to 2011 were retrospectively reviewed from prospectively collected data. The need for shunt placement was determined by the awake test, based on the alteration in the neurologic examination. We collected data by using the clinical records and imaging studies, and investigated factors related to selective shunt such as collateral circulation and contralateral internal carotid artery (ICA) stenosis.

RESULTS

There were 45 CEAs under regional anesthesia with the awake test in 44 patients. The mean age was 61.8 ± 7.1 years old. There were 82.2% (37/45) of males, and 68.9% (31/45) of symptomatic patients. Selective shunt placement had been performed in only two (4.4%) patients. Among them fewer cases (4%) had severe (stenosis >70%) contralateral ICA lesions, and more cases (91%) of complete morphology of the anterior or posterior circulation in the circle of Willis. There was no perioperative stroke, myocardial infarctionor death, and asymptomatic new brain lesions were detected in 4 patients (9%), including 2 cases of selective shunt placement.

CONCLUSION

CEA under routine awake test could besafe and feasible method with low shunt placement rate in selected patients.

Cerebral Intolerance During Flow Arrested Carotid Angioplasty

Introduction: The use of flow arrest as a means of providing cerebral protection during carotid angioplasty offers the advantages of improved efficiency of debris removal and the ability to provide protection under unfavorable (tortuous) anatomic circumstances. However, in contrast to the filtration methods of cerebral protection, this modality requires complete interruption of antegrade carotid artery flow during balloon angioplasty and stent deployment. Methods: We report our experience with 9 patients undergoing carotid angioplasty with the Mo.Ma device, which utilizes common and external carotid artery balloon occlusion during the angioplasty procedure. We assessed the clinical outcomes and intraprocedural hemodynamic data. Results: The average duration of carotid occlusion was 8.3 minutes. Of the 9 patients, 2 patients (22%) experienced cerebral intolerance. No stroke occurred in this patient cohort. There appeared to be a poor relationship between procedure intolerance and the presence of significant contralateral stenosis or low carotid back pressure. Furthermore, the incidence of postangioplasty hypotension was not clearly related to cerebral intolerance. Conclusion: Carotid angioplasty with stenting can be safely conducted with flow arrest as an alternative to filter-type cerebral protection devices. However, because cerebral intolerance is not an infrequent occurrence with this approach, clinicians must be cognizant of management strategies for transient cerebral intolerance.

Shunting during carotid endarterectomy

BACKGROUND

The use of shunting during carotid endarterectomy (CEA) is controversial. While some surgeons advocate routine shunting, others prefer selective shunting or no shunting. Several large series have documented excellent results of CEA with routine shunting or without shunts. Others reported similar results with selective shunting using transcranial Doppler (TCD), electroencephalogram (EEG) monitoring, carotid stump pressure (SP), cervical block anesthesia (CBA), and somatosensory evoked potential (SSEP). In this study, we review the available evidence supporting shunting, nonshunting, and selective shunting during CEA.

METHODS

An electronic PubMed/MEDLINE search was conducted to identify all published CEA studies between January 1990 and December 2010, that analyzed the perioperative outcome of routine shunting, routine nonshunting, routine versus selective shunting, selecting shunting versus avoiding a shunt, and selective shunting based on EEG, TCD, SP, CBA, and SSEP.

RESULTS

The mean reported perioperative stroke rate for CEAs with routine shunting was 1.4% and for routine nonshunt was 2%. Meanwhile, the mean perioperative stroke rates for selecting shunting were 1.6% using EEG, 4.8% using TCD, 1.6% using SP, 1.8% using SSEP, and 1.1% for CBA. Similar results were noted for perioperative stroke and death rates.

CONCLUSIONS

The use of routine shunting and selective shunting was associated with a low stroke rate. Both methods are acceptable, and the individual surgeon should select the method with which they are more comfortable.

Cerebral oximetry and stump pressure as indicators for shunting during carotid endarterectomy: comparative evaluation

The purpose of this work is to investigate the correlation between regional oxygen saturation (rSO2) changes and stump pressure (SP) during cross-clamping of the internal carotid artery in carotid endarterectomy (CEA) and verify the perspectives of rSO2 to become a criterion for shunting. Sixty consecutive CEAs under general anesthesia were studied prospectively. Selective shunting was based on SP ≤40 mmHg exclusively. Regression analysis with high order terms and receiver operating characteristic analysis were performed to investigate the association between ΔrSO2(%) and SP and to determine an optimal ΔrSO2(%) threshold for shunt insertion. A quadratic association between ΔrSO2(%) and SP was documented regarding the baseline to one and five minutes after cross-clamping intervals. A cut-off of 21 and 10.1% reduction from the baseline recording was identified as optimal for the distinction between patients needed or not a shunt regarding the first and fifth minute after cross-clamping, respectively. In conclusion, cerebral oximety reflects sufficiently cerebral oxygenation during CEA compared with SP, providing a useful mean for cerebral monitoring.

Correlation of intraoperative collateral perfusion pressure during carotid endarterectomy and status of the contralateral carotid artery and collateral cerebral blood flow

BACKGROUND

The optimal method for predicting when carotid shunting is not necessary during carotid endarterectomy (CEA) is controversial. This study will analyze the correlation of collateral perfusion pressure and the status of contralateral carotid/cerebral collaterals and determine whether preoperative duplex ultrasound/cerebral angiography can predict when CEA can be done without shunting.

METHODS

Ninety-eight patients were randomized into routine shunting and 102 into selective shunting when the collateral perfusion pressure (systolic carotid stump pressure) was <40 mm Hg during CEA. All patients had preoperative carotid duplex ultrasound and 87 had angiography, the results of which were evaluated for the presence of collateral flow from the contralateral carotid artery or posterior circulation through the anterior and/or posterior communicating arteries.

RESULTS

The perioperative stroke rate was 1.5% for the entire group. There was no correlation between preoperative symptoms and the status of the contralateral carotid artery (normal, stenosed, or occluded). The mean collateral perfusion pressure was inversely related to the severity of the contralateral carotid stenosis: 60, 57, 55, 56, and 38 mm Hg for normal, <50% stenosed, 50-69% stenosed, 70-99% stenosed, and occluded arteries, respectively (p = 0.005). There was a direct relation between the number of patients with a collateral perfusion pressure of <40 mm Hg (shunted group) and the severity of the contralateral carotid stenosis: 6 of 62 (10%) for normal carotid, 7 of 43 (16%) for <50% stenosis (OR = 1.82), 12 of 69 (17%) for 50-69% stenosis (OR = 1.97), 3 of 10 (30%) for 70-99% stenosis (OR = 4, CI = 0.81-19.68), and 9 of 13 (70%) for occlusion (OR = 21, CI = 4.98-89.32) (p < 0.0001). None of the patients (0/56) with normal to <70% contralateral carotid stenosis with cross-filling had a collateral perfusion pressure of <40 mm Hg (no shunting was necessary). However, 9 of 17 (47%) patients with <70% contralateral carotid stenosis and no cross-filling had a collateral perfusion pressure of <40 mm Hg (p < 0.0001), whereas 6 of 7 (86%) patients with ≥70% contralateral carotid stenosis and cross-filling versus 2 of 7 (29%) with ≥70% contralateral carotid stenosis and no cross-filling had a collateral perfusion stump pressure of >40 mm Hg (p = 0.1026). Overall, 62 of 63 (98.4%) patients with cross-filling versus 10 of 24 (42%) without cross-filling had a collateral perfusion pressure of ≥40 mm Hg (p < 0.0001).

CONCLUSIONS

There was an inverse correlation between collateral perfusion pressure and severity of contralateral carotid stenosis, and patients with severe contralateral carotid stenosis/occlusion were more likely to be shunted. The presence of cross-filling with normal to <70% contralateral carotid stenosis was associated with a collateral perfusion stump pressure of ≥40 mm Hg in 100% of patients for whom shunting was not carried out in our series.