Selective Shunting Research Articles

Severe contralateral carotid stenosis or occlusion drive 30-day risk after carotid endarterectomy.

The significant effects on the treatment of severe carotid stenosis by carotid endarterectomy have been widely recognized. However, it is controversial whether patients with severe contralateral carotid stenosis or occlusion (SCSO) can benefit from carotid endarterectomy surgery. This study aimed to estimate the SCSO effects on early outcomes after carotid endarterectomy with selective shunting. Between August 2011 and October 2019, a total of 617 patients who underwent carotid endarterectomy with selective shunting were analyzed. SCSO was defined as >70% luminal narrowing of the contralateral extracranial carotid stenosis or occlusion. Of these patients, 116 were categorized into an SCSO group while the rest were assigned to the non-SCSO group. Primary study outcomes were the occurrence of major adverse events, defined as stroke, all-cause mortality, and myocardial infarction during the perioperative period after carotid endarterectomy. Traditional multivariable logistic regression model and logistic regression model adjusted for propensity scores were used to estimate the SCSO effects on primary outcomes. Interaction and stratified analyses were conducted according to age, sex, comorbidities (hypertension, diabetes), preoperative neurological deficit, preoperative symptoms, and shunt use. Mean age was 68.5 ± 9.2 years (86.1% men). Overall major adverse events rate within 30 days was 2.5%. Major adverse events rates in SCSO and non-SCSO groups were 9.5% and 1.6%, respectively. This difference was statistically significant (p < 0.001). In multivariable regression analysis, patients with SCSO had a higher risk of major adverse events (non-SCSO vs. SCSO: aOR 5.05 [95% CI, 1.78-14.55]). In 342 propensity score matched patients, results were consistent (propensity score: aOR, 3.78 [95% CI, 1.13-12.64]). SCSO is an independent predictor of 30-day major adverse events. Whether these patients with SCSO are suitable for carotid endarterectomy should be carefully considered.

Poor Neurological Deficit Was an Independent 30-day Risk Factor in Symptomatic Carotid Stenosis after CEA with Selective Shunting

Carotid endarterectomy (CEA) prevents the occurrence of stroke in the future, although its efficacy depends on the detection and control of high perioperative risk factors. We aimed to analyze the association between preoperative neurological deficit and the 30-day risk of major adverse cardiovascular events (MACEs) in CEA with selective shunting for symptomatic carotid stenosis. We assessed 653 patients who underwent CEA with selective shunting for symptomatic carotid stenosis between August 2011 and August 2019. The primary outcomes of the study were the occurrence of MACEs, defined as stroke (ischemic stroke or cerebral hemorrhage), all-cause mortality, and myocardial infarction during the perioperative period after CEA. Baseline patient characteristics were analyzed to identify factors associated with perioperative (<30days) MACEs. Multivariable logistic regression models were used to estimate the association between preoperative modified Rankin Scale (mRS) and the 30-day risk of MACEs. Interaction and stratified analyses were conducted according to age, drinking, history of hypertension and coronary artery disease, and surgical side. The mean age of patients was 68.7±9.1years, and 86.4% were men. The 30-day MACEs rate was 2.5%. In univariate logistic regression, histories of coronary artery disease (odds ratio (OR), 2.57 [95% confidence interval (CI), 1.04-6.34]), a severe contralateral carotid stenosis or occlusion (OR, 4.52 [95% CI, 1.84-11.11]), and a poor neurological deficit (mRS ≥ 3 versus mRS < 3: OR, 3.78 [95% CI, 1.21-11.82]) were associated with higher primary outcome rates. A history of hypertension did not increase the risk of MACEs (OR, 0.37 [95% CI, 0.15-0.89]). In the multivariable regression analysis, poor neurological deficit was associated with a higher risk of the MACEs within 30days (mRS ≥ 3 versus mRS < 3: 11.1% vs. 2.0%, adjusted OR 5.70 [95% CI, 1.50-21.60]). The interaction analysis revealed no interactive role in the association between neurological deficit and 30-day risk of MACEs. Poor neurological deficit was an independent risk factor associated with the 30-day risk of MACEs in symptomatic patients who underwent CEA with selective shunting. Our findings may provide guidance to surgeons when treating patients with poor neurological deficit. The decision to perform surgery should be made after careful consideration.

Comparison of Single and Dual Monitoring during Carotid Endarterectomy

We compared the rate of selective shunt and pattern of monitoring change between single and dual monitoring in patients undergoing carotid endarterectomy (CEA). A total of 121 patients underwent 128 consecutive CEA procedures. Excluding five procedures using internal shunts in a premeditated manner, we classified patients according to the monitoring: Group A (n = 72), patients with single somatosensory evoked potential (SSEP) monitoring; and Group B (n = 51), patients with dual SSEP and motor evoked potential (MEP). Among the 123 CEAs, an internal shunt was inserted in 12 procedures (9.8%) due to significant changes in monitoring (Group A 5.6%, Group B 15.7%, p = 0.07). The rate of shunt use was significantly higher in patients with the absence of contralateral proximal anterior cerebral artery (A1) on magnetic resonance angiography (MRA) than in patients with other types of MRA (p <0.001). Significant monitor changes were seen in 16 (12.5%) in both groups. In four of nine patients in Group B, SSEP and MEP changes were synchronized, and in the remaining five patients, a time lag was evident between SSEP and MEP changes. In conclusion, the rate of internal shunt use tended to be more frequent in patients with dual monitoring than in patients with single SSEP monitoring, but the difference was not significant. Contralateral A1 absence may predict the need for a shunt and care should be taken to monitor changes throughout the entire CEA procedure. Use of dual monitoring can capture ischemic changes due to the complementary relationship, and may reduce the rate of false-negative monitor changes during CEA.

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

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. at our Institution, 837 patients underwent CEA across 8years. Although the surgicaltechnique 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). A selective shunting policy was needed in 5.1%, together with general anesthesia. Overall operative time was 63.9±15.1minutes (61.4±12.5 and 66±16.9minutes in Group A and Group B respectively; P<0.001) and cross-clamp time 19.3±2.9minutes (19.0±3.2 vs. 19.5±2.8, P=0.009). At 30days, 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 22.5months, 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 24months 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 37months, the overall survival rate at 24months was 97.9%in Group A, and 97.9% in Group B, with no between-group difference (P=0.070). 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.

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

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. 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. 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%. 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.

Augmentation of Pulmonary Arterial Growth in Single Ventricle Patients by Interim Selective Shunts

Stenosis or diffuse hypoplasia of central pulmonary arteries (PA) is common in patients with single ventricle physiology, often requiring surgical patching. Such repairs are prone to failure, particularly with low pressure venous flow (bidirectional cavopulmonary connection or Fontan). We describe our experience of disconnection of central PA and selective systemic-PA shunt to the hypoplastic vessel. Single ventricle patients (n = 12) with diffuse left pulmonary artery (LPA) hypoplasia (LPA:right pulmonary artery diameter <0.7) underwent PA disconnection (ligation clip) and selective arterial shunt to the LPA. Patients with ≤mild atrioventricular valve regurgitation, and no more than mild systolic dysfunction on echocardiogram were considered. Following systemic-LPA shunt, patients were reassessed by cardiac catheterization prior to further surgery, with follow-up catheterization later performed and description of changes observed. Increased volume loading was well tolerated with no greater than mild atrioventricular valve regurgitation and preserved systolic function (normal or mildly reduced). Selective arterial shunting increased the caliber of the LPA from 4.1 mm (1.2-5.6) to 6.5 mm (1.7-11.9) and this increase was preserved post-Fontan (6.7 mm [1.3-8.0]) (median [range]). Ventricular end diastolic pressure increased with arterial shunting but resolved after shunt takedown and Fontan completion (median +3 and -4 mm Hg respectively). Post-Fontan hospital length of stay was not prolonged (median 11 days, range 7-14). No deaths occurred. In univentricular hearts and PA hypoplasia, selective systemic-PA shunting physiologically increases the caliber of the distal vessels. In selected patients this can be done safely with maintenance of PA growth and resolution of the elevated end diastolic pressure with Fontan completion.

W. Dean Warren, MD, FACS, Father of Selective Shunts for Variceal Hemorrhage: Lessons Learned.

Dr Dean Warren was born in 1924 and died prematurely from cancer in 1989. He was a man of uncommon intelligence, wit, collegiality, integrity, honesty, and a true leader in American surgery. In 1966, he and his colleagues (Drs Zeppa and Fomon) presented a new concept for surgical shunts to control variceal hemorrhage while maintaining portal perfusion or hepatopetal blood flow. He termed this new shunt the distal splenorenal shunt (DSRS), which was the first selective shunt invented. The DSRS selective shunt was a brilliant improvement over the total shunt concept proposed by Nicolai Eck and was practiced worldwide during the 1980s. In a space of 2 decades, Dr Warren's pioneering work would show that the selective DSRS was superior to total shunts for treatment of portal hypertension, but that endoscopic sclerotherapy was a better first-line treatment for variceal hemorrhage than his own creation. His absolute adherence to the principles he espoused in his presidential address to the Society for Surgery of the Alimentary Tract in 1973 were employed in his research and treatment of patients. This paper details Dr Warren's extraordinary research accomplishments and sets a lesson for us that well-designed clinical trials including randomization are essential in the advancement of the care of surgical patients.

Predictive Factors for 30-Day Stroke and Death Rate in a Contemporary Series of Carotid Endarterectomies Performed for Asymptomatic Stenosis of the Internal Carotid Artery

The objective was to retrospectively analyze the perioperative outcomes of carotid endarterectomy (CEA) performed for asymptomatic carotid stenosis in the last decade and to identify predictors of increased risk of stroke and death in a single-center experience. From January 2008 to December 2018, 2501 consecutive CEAs were performed in a single academic institution. Data concerning these interventions were prospectively collected in a dedicated database. A retrospective analysis of the database was performed, and 1956 interventions performed in asymptomatic patients were found. Univariate and multivariate (forward logistic regression) analyses were used to identify potentially significant predictors of stroke and death rate at 30 days and to calculate their weight in determining it. Thirty-day stroke and death rates were then assessed for each subgroup of different predictors. Overall, 30-day stroke and death rate was 0.9% (17 cases). On multivariate analysis, male sex, diabetes, and combined cardiac surgery and the need for selective shunting were identified as independent predictors of stroke and death at 30 days; 22.3% of patients did not have any predictor, whereas 51.3%, 23.1%, and 3.2% of the patients had one, two, or three predictors, respectively. No patient had four predictors. Thirty-day stroke and death rate for patients without any of the identified predictors was 0.2% (1 case/436 interventions), whereas the corresponding figures for patients with one, two, or three predictors were 0.7% (7 cases/1006 interventions; P = .7 in comparison with patients with no predictors), 1% (4 cases/451 interventions; P = .1 in comparison with patients with no predictors and P = .7 in comparison with patients with one predictor), and 8.5% (5 cases/63 interventions; P < .001 in comparison with patients with no predictor, one predictor, or two predictors). A subgroup of asymptomatic patients undergoing CEA with a prohibitive perioperative risk does exist, thus questioning the indication for surgery in such patients.

Indication of Selective Shunting During Carotid Endarterectomy: 1D–0D Hemodynamic Simulation of Cerebral Perfusion

The circle of Willis is the main collateral circulation in the brain during internal carotid artery occlusion. Carotid stump pressure (CSP) is an established substitute measure of cerebral collateral circulation during carotid endarterectomy. Stenosis and occlusion of the contralateral internal carotid artery are thought to be risk factors.

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

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. 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. 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 <30mm 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 1.6days. This is one of the largest contemporary series of CEA using a 30mm 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.

Benefit of selective shunt use during carotid endarterectomy under regional anesthesia.

Carotid cross-clamping during endarterectomy exposes the patient to intraoperative neurological deficits due to embolism or cerebral hypoperfusion. To prevent further cerebrovascular incidents, resorting to shunt is frequently recommended. However, since this method is also considered a stroke risk factor, the use is still controversial. This study aims to shed some light on the best approach regarding the use of shunt in symptomatic cerebral malperfusion after carotid artery cross-clamping. From January 2012 to January 2018, 79 patients from a tertiary referral hospital who underwent carotid endarterectomy with regional anesthesia for carotid artery stenosis and manifested post-clamping neurologic deficits were prospectively gathered. Shunt use was left to the decision of the surgeon and performed in 31.6% (25) of the patients. Demographics, comorbidities, imaging tests, and clinical/intraoperative features were evaluated. For data assessment, univariate analysis was performed. Regarding 30-day stroke, 30-day postoperative complications (stroke, surgical hematoma, hyperperfusion syndrome), and cranial nerve injury, no significant differences were found (P = 0.301, P = 0.460, and P = 0.301, respectively) between resource to shunt and non-shunt. Clamping and surgery times were significantly higher in the shunt group (P < 0.001 and P = 0.0001, respectively). Selective-shunting did not demonstrate superiority for patients who developed focal deficits regarding stroke or other postoperative complications. However, due to the limitations of this study, the benefit of shunting cannot be excluded. Further randomized trials are recommended for precise results on this matter with current sparse clinical evidence.

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.

Abstract WP176: Contributing Factors Affecting the Occurrence of New Ischemic Lesions After Carotid Revascularization

Introduction: Although several large clinical trials have demonstrated that carotid revascularization including carotid endarterectomy (CEA) and carotid stenting (CAS) are effective treatments for symptomatic patients with internal carotid stenosis, the factors contributing to post-revascularization stroke have not yet well defined. Objectives: We aimed to analyze the factors that are associated with the presence of new ischemic lesions on diffusion-weighted MRI (DWI) after carotid revascularization. Methods: Consecutive clinical and imaging findings of patients who underwent CEA or CAS were collected (n=159). New ischemic lesions were defined based on DWI within 3 days after carotid intervention. Transcranial Doppler (TCD) monitoring findings during surgical operation including the number of microemboli (MES), status of collateral via Willis circle, and differences in pre- and post-operation peak systolic velocity and mean velocity were evaluated. Results: We analyzed 116 patients who underwent DWI before and after carotid intervention (72 in the CEA group and 44 in CAS group). DWI revealed new ischemic lesions in 53 patients (5 in females vs. 48 in males, p=0.579). This non-randomized study showed a higher rate of postprocedural ischemic lesion on DWI after CAS compared with CEA (70.5% vs. 30.6%, p&lt;0.001). There was no significant association between new lesions on DWI and symptomatic stenosis (p=0.624) or degree of stenosis (p=0.498). The numbers of MES during TCD monitoring showed a trend for association with new lesions on DWI (p=0.056). Using a shunt during the operation was the only independent predictor of new lesions by multivariate analysis (OR 6.92, 95% CI 1.65 to 29.98, p=0.008). Conclusion: New ischemic lesions on DWI occur more frequently after CAS than CEA. Restriction of selective shunting during CEA can reduce new ischemic lesions after carotid intervention. Efforts to prevent the occurrence of new ischemic lesions are expected to lead to better outcomes.

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.

Endovascular Treatment of Cavernous Sinus Dural Arteriovenous Fistulae: Review of the Literature and Current Status.

Cavernous sinus dural arteriovenous fistulae (CSdAVFs) are characterized by the shunts between dural arteries and dural veins surrounding the cavernous sinus (CS), causing ocular symptoms in addition to intracranial hemorrhage and infarction. As surgical access is difficult, endovascular treatment (EVT) has been considered and performed as the first-line therapy for decades. Although there have been recent advances in techniques and devices, transvenous embolization (TVE) with platinum coils remains the most common procedure. There are multiple access routes to the CS, such as the inferior petrosal sinus, superior ophthalmic vein (SOV), and intercavernous sinus from the contralateral CS. To extirpate the shunt, packing the entire sinus with coils is adopted, occasionally resulting in persistent cranial nerve palsy (CNP) due to compression of the coil mass. To avoid this complication, selective shunt occlusion (SSO), in which the coils are placed in the shunted pouch (SP) defined by the small restricted space where the arterial flow converges, is an effective and safe method. Transarterial embolization (TAE) is another option and use of liquid embolic materials, such as Onyx may be promising; however, the potential risk of ischemic nerve injury due to undesirable ante/retrograde influx of the liquid materials is of concern. In conclusion, EVT, especially TVE, is a safe and effective method for managing CSdAVFs. Understanding the angioanatomy consisting of the feeding artery, shunt point, and the drainage route, including the latent vessels, is essential for a good outcome.

Selective versus non-selective shunts for the prevention of variceal rebleeding

Selective versus non-selective shunts for the prevention of variceal rebleeding

Examination of the interaction between method of anesthesia and shunting with carotid endarterectomy

BackgroundAlthough the choice of anesthesia during carotid endarterectomy (CEA) does not seem to increase the risk of perioperative stroke, it might affect the outcomes of shunting during CEA. This study aims to evaluate whether the choice of anesthesia modifies the association between shunting and in-hospital stroke/death after CEA. MethodsWe retrospective reviewed all CEA cases performed between 2003 and 2017 in the Vascular Quality Initiative. Patients were divided into three groups: (1) no shunting during CEA (n = 29,227 [48.4%]), (2) routine shunting (n = 28,673 [47.5%]), and (3) selective shunting based on an intraoperative indication (n = 2499 [4.1%]). Multivariable logistic regression analysis was used to study the interaction between anesthesia (local anesthesia [LA]/regional anesthesia [RA] vs general anesthesia [GA]) and intraoperative shunting (no shunting vs routine and selective shunting) during CEA in predicting the risk of in-hospital stroke/death after CEA. ResultsThe final cohort included 60,399 patients. The majority of CEA cases (90.2%) were performed under GA. Of the study cohort, 29,227 (48.4%) underwent CEA without shunting, 28,673 patients (47.5%) had routine shunting, and the remaining (n = 2499 [4.1%]) were selectively shunted. The interaction between intraoperative shunting and anesthesia in predicting in-hospital stroke/death was statistically significant (P < .05). When CEA is performed under LA/GA, routine shunting was associated with 3.5 times the adjusted odds of in-hospital stroke/death after CEA (odds ratio [OR], 3.5; 95% confidence interval [CI], 1.8-6.8; P < .001) compared with no shunting, whereas selective shunting was associated with 7.1 the odds (OR, 7.1; 95% CI, 3.5-14.7; P < .001). In contrast, under GA, there was no significant association between routine shunting and in-hospital stroke/death (OR, 1.2; 95% CI, 1.0-1.5; P = .12), whereas selective shunting was associated with 1.7 times the odds (OR, 1.7; 95% CI, 1.2-2.4; P < .01) compared with not performing shunting during CEA. ConclusionsThe use of LA/RA is associated with increased odds of stroke/death compared with GA when intraoperative shunting is performed. The effect of anesthesia is more pronounced in patients who develop clamp-related ischemia and undergo selective shunting. More controlled studies are needed to explain these findings and validate them.

CAR 2. Multimodal Neurophysiologic Monitoring Reduces Shunt Incidence During Carotid Endarterectomy

The use of a shunt during carotid surgery is controversial. Good results have been found in the literature both with routine use of a shunt and with no shunt during general anesthesia. Other studies report similar results with selective shunting with the support of cerebral monitors. Different experiences are found in the literature with transcranial Doppler (TCD), electroencephalography (EEG), stump pressure (SP), and somatosensory evoked potentials (SSEP). To the best of our knowledge, there are no controlled studies to document the relative efficacy of these techniques. The purpose of this study was to describe the results of our experience using multimodal neurophysiologic monitoring by EEG with SSEP for cerebral monitoring during carotid surgery. We conducted a retrospective analysis of patients treated with carotid endarterectomy in our unit in the last 2 years. We used several forms of cerebral monitoring. Until 2017, we preferred SP with TCD or, if that was not available, EEG. Since 2017, we introduced EEG with SSEP, always in association with SP. We analyzed those two groups of patients before and after introduction of EEG with SSEP. From January 2016 to December 2018, we performed 156 carotid revascularizations. In the first group of 93 patients treated under combined SP and TCD (or EEG), we observed one stroke (1.1%) and two transient ischemic attacks (2.1%); we selectively used a shunt in 21 cases (22.5%). In the second group of 63 patients who had SP and EEG with SSEP monitoring, we observed one stroke (1.5%) and two transient ischemic attacks (3.1%); a shunt was necessary in 12 cases (12.9%). Combination of different methods allows minimal shunt use during carotid surgery. EEG with SSEP monitoring during carotid surgery has been demonstrated to be safe and sensitive for prediction of cerebral ischemia during carotid clamping. In our experience, EEG with SSEP monitoring represents an effective parameter to indicate shunting.

Outcomes for carotid endarterectomy in nonagenarians

ObjectiveCarotid endarterectomy (CEA) is a well-established procedure with prospective randomized data demonstrating the benefit of stroke prevention. With the aging of the population, there are limited data published for nonagenarians, especially for asymptomatic stenosis. This study investigated 30-day morbidity and mortality as well as late survival in symptomatic and asymptomatic nonagenarians with severe carotid stenosis undergoing CEA. MethodsA retrospective review was conducted of a single vascular surgery group's registry involving multiple hospitals between November 1994 and June 2017 for all primary CEAs of patients ≥90 years old at the time of surgery. The exclusion criterion was redo surgery or bilateral CEAs. Demographic data, sex, symptoms, risk factors, and postoperative complications were analyzed. Survival analysis was conducted using SPSS software (IBM Corp, Armonk, NY) for the specific end point 30-day morbidity or mortality and late survival. ResultsThere were 77 patients (44 male [57%]) who underwent CEA for symptomatic (44 [57%]) and asymptomatic (33 [43%]) internal carotid artery stenosis with a median age of 92 years; 23 women were symptomatic compared with 21 men, and 23 men were asymptomatic compared with 10 women. Symptomatic patients included amaurosis fugax (n = 3), stroke (n = 16), and transient ischemic attack (n = 25). CEAs were performed using the eversion technique under cervical block with selective shunting. The 30-day morbidity included one (2.3%) nonfatal myocardial infarction and one (2.3%) ischemic stroke in the symptomatic group compared with one (3%) patient having a nonfatal myocardial infarction and none with ischemic stroke in the asymptomatic group. One patient of the symptomatic group required return to the operating room for hematoma evacuation. The 30-day mortality was 2.3% in the symptomatic group compared with 6.1% in the asymptomatic group. There was no statistical difference in survival based on sex (P = .444). The symptomatic and asymptomatic groups had similar median survival of 27.7 months and 29.4 months (P = .987), respectively. ConclusionsThe aging population adds increasing difficulty in decision-making for surgical intervention on carotid stenosis. CEA in nonagenarians is associated with reasonably low 30-day rates of ischemic stroke and myocardial infarction in our small study. However, enthusiasm for asymptomatic CEA in this population must be tempered by low survival rates.