Carotid Cross-clamping Research Articles

Lacidipine, thiamine pyrophosphate and their combination on the ocular ischemic syndrome induced by bilateral common carotid artery ligation.

To investigate the effect of lacidipine, thiamine pyrophosphate (TPP) and the combination of lacidipine and TPP against oxidative and inflammatory eye damage induced by bilateral common carotid artery ligation in rats. Male albino Wistar rats were categorized as those who underwent sham surgery (SG), right and left common carotid cross-clamping and unclamping procedure (CCU), lacidipine+CCU (LCCU), TPP+CCU (TCCU), and combination of lacidipine and TPP (LTC)+CCU (LTCCU). One hour before anesthesia, the LCCU (n=6) received lacidipine (4 mg/kg, orally) and the TCCU (n=6) received TPP (20 mg/kg, intraperitoneally). The SG (n=6) and CCU (n=6) received the same volume of distilled water from the same route. After anesthesia (60 mg/kg ketamine, intraperitoneally), the necks of the rats were opened in the midline. Ischemia was created for 10min by placing clips on the right and left common carotid arteries. Rats in the SG only underwent subcutaneous incision. After 10min, the clips were removed and reperfusion was achieved for six days. Then, the animals were euthanized (120 mg/kg ketamine, intraperitoneally) and the levels of oxidant, antioxidant and proinflammatory cytokines in the eye tissues were determined. The retinal tissue of the eye was also examined histopathologically. Lacidipine, TPP, and LTC significantly prevent the increase in malondialdehyde, tumor necrosis factor-alpha, interleukin-1β (IL-1β), and IL-6 levels, decrease in total glutathione levels, superoxide dismutase and catalase activities and histopathological retinal damage in eye tissue induced by bilateral common carotid artery ligation in rats. The impact of these drugs on protection is determined to be LTC>lacidipine>TPP. As a result of the study, it is concluded that LTC may be more effective than lacidipine and TPP alone in treating ocular ischemic syndrome.

Prospective single-center study on the reliability of ipsilateral cerebral oximetry using near-infrared spectroscopy as a predictor for selective shunting during carotid endarterectomy.

Many techniques are available for the intraoperative assessment of brain perfusion during carotid endarterectomy, such as carotid stump pressure, near-infrared spectroscopy, somatosensory evoked potentials, transcranial Doppler, electroencephalography, and clinical assessment. The decision for selective carotid shunt insertion is dependent on clinical deterioration or the detection of cerebral hypoperfusion after cross-clamping of the internal carotid artery. Monitoring cerebral oximetry using near-infrared spectroscopy is a noninvasive technique for cerebral oxygen saturation measurement, reflecting changes in cerebral blood flow during carotid endarterectomy. The aim of this study was to evaluate the reliability of near-infrared spectroscopy as a predictor of selective shunting during carotid endarterectomy. In total, 47 conventional carotid endarterectomy surgeries were performed at our hospital between March 2016 and December 2021. All surgeries were performed under a regional cervical block supplemented with local infiltration anesthesia. All patients were monitored by cerebral oximetry using bilateral near-infrared spectroscopy probes and clinical assessment through communication with the patient (numerical, visual, and verbal) to indicate a selective shunt. Near-infrared spectroscopy values were recorded before and after internal carotid cross-clamping and after declamping. Any decrease in ipsilateral cerebral oximetry-near-infrared spectroscopy values equal to or more than 20% from the pre-clamping baseline reading associated with deterioration in neurological status (hemiparesis, aphasia, or deterioration in level of consciousness) after internal carotid artery cross-clamping was considered an indication for intraluminal carotid shunting. After internal carotid artery cross-clamping, 5 of 47 patients (10.6%) developed a significant drop in cerebral oxygen saturation associated with obvious clinical assessment deterioration in verbal communication and weakness in contralateral arm power. A Pruitt-Inahara carotid shunt was subsequently inserted, and 42 patients remained stable throughout surgery. The average decline in ipsilateral near-infrared spectroscopy values was 23.8% in patients with clinical deterioration. The average decline was 8.6% in patients who remained stable. Monitoring ipsilateral cerebral oximetry using near-infrared spectroscopy is an easy and reliable method for indicating selective shunting during carotid endarterectomy. A 20% decrease in ipsilateral brain tissue oximetry after internal carotid artery cross-clamping provides a reliable cut-off value for selective intraluminal carotid shunting during carotid endarterectomy.

Near-Infrared Spectroscopy-Guided, Individualized Arterial Blood Pressure Management for Carotid Endarterectomy under General Anesthesia: A Randomized, Controlled Trial.

Background: Differences in blood pressure can influence the risk of brain ischemia, perioperative complications, and postoperative neurocognitive function in patients undergoing carotid endarterectomy (CEA). Methods: In this single-center trial, patients scheduled for CEA under general anesthesia were randomized into an intervention group receiving near-infrared spectroscopy (NIRS)-guided blood pressure management during carotid cross-clamping and a control group receiving standard care. The primary endpoint was postoperative neurocognitive function assessed before surgery, on postoperative days 1 and 7, and eight weeks after surgery. Perioperative complications and cerebral autoregulatory capacity were secondary endpoints. Results: Systolic blood pressure (p < 0.001) and norepinephrine doses (89 (54-122) vs. 147 (116-242) µg; p < 0.001) during carotid cross-clamping were lower in the intervention group. No group differences in postoperative neurocognitive function were observed. The rate of perioperative complications was lower in the intervention group than in the control group (3.3 vs. 26.7%, p = 0.03). The breath-holding index did not differ between groups. Conclusions: Postoperative neurocognitive function was comparable between CEA patients undergoing general anesthesia in whom arterial blood pressure during carotid cross-clamping was guided using NIRS and subjects receiving standard care. NIRS-guided, individualized arterial blood pressure management resulted in less vasopressor exposition and a lower rate of perioperative complications.

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

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. 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. Overall, 102 patients (61 men and 41 women) who underwent carotid artery endarterectomy under local anesthesia were included, with an age range of 51-88years. 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 ≤48mmHg, sensitivity was 93.8%, and specificity was 61.6% (area under the curve: 0.773, p < 0.0001). 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.

The Gupta Perioperative Risk for Myocardial Infarct or Cardiac Arrest (MICA) Calculator as an Intraoperative Neurologic Deficit Predictor in Carotid Endarterectomy.

Patients undergoing carotid endarterectomy (CEA) may experiment intraoperative neurologic deficits (IND) during carotid cross-clamping. This work aimed to assess the impact of the Gupta Perioperative Myocardial Infarct or Cardiac Arrest (MICA) risk calculator in the IND. From January 2012 to April 2021, patients undergoing CEA with regional anaesthesia for carotid stenosis with IND and consecutively control operated patients without IND were selected. A regressive predictive model was created, and a receiver operating characteristic (ROC) curve was applied for comparison. A multivariable dependence analysis was conducted using a classification and regression tree (CRT) algorithm. A total of 97 out of 194 included patients developed IND. Obesity showed aOR = 4.01 (95% CI: 1.66-9.67) and MICA score aOR = 1.21 (1.03-1.43). Higher contralateral stenosis showed aOR = 1.29 (1.08-1.53). The AUROC curve was 0.656. The CRT algorithm differentiated obese patients with a MICA score ≥ 8. Regarding non-obese patients, the model identified the presence of contralateral stenosis ≥ 55% with a MICA ≥ 10. MICA score might play an additional role in stratifying patients for IND in CEA. Obesity was determined as the best discrimination factor, followed by a score ≥ 8. A higher ipsilateral stenosis degree is suggested to have a part in avoiding procedure-related IND. Larger studies might validate the benefit of MICA score regarding the risk of IND.

Chapter 19 - Monitoring in carotid endarterectomy

Cerebral ischemia during carotid endarterectomy occurs via several mechanisms: inadequate collateral blood flow during carotid cross-clamping, thromboembolism due to carotid manipulation, and/or rethrombosis at the surgical site. Perioperative strokes increase not only the morbidity of endarterectomy but also its short- and long-term mortality. However, while several predictors of cerebral ischemia have been identified, precise individual risk is hard to assess. Since nonselective shunting during carotid cross-clamping is neither risk-free nor eliminates perioperative stroke, it is advisable to apply intraoperative monitoring techniques for detection and reversal of cerebral ischemia, which may occur at various stages of the procedure. This chapter addresses the methods available for monitoring, with an emphasis on neurophysiologic techniques, which are preferable given their direct assessment of how a decrease in cerebral blood flow impacts brain function. These include electroencephalography, somatosensory evoked potentials, and transcranial motor evoked potentials. Details regarding the methodology, advantages, disadvantages, and interpretation of these tests will be discussed within the anatomic, physiologic, surgical, and anesthetic contexts.

Intraoperative microembolic signals during carotid endarterectomy

Transcranial Doppler ultrasonography (TCD) can detect microembolic signals (MESs) that are one of the pathogenic indications of ischemic stroke. However, MESs are not uncommon findings during carotid endarterectomy (CEA). The aim of this study was to evaluate the association between MESs and postoperative neurologic events (transient ischemic attack [TIA] or stroke) or new brain lesions (NBLs) on magnetic resonance imaging (MRI). Of the 205 patients who underwent CEA, 160 who were monitored intraoperatively for MES using TCD were enrolled and reviewed retrospectively. MESs were counted until carotid cross-clamping. Postoperative neurologic examination and MRI was performed between postoperative day 1 and 7 in 131 patients. The binary logistic regression model was used to identify independent predictors of postoperative neurologic events or NBLs. MESs during dissection or carotid clamping was observed in 50 patients (31%) and 20 patients (13%) showed MESs > 10. The postoperative ischemic stroke rate was 3% (4/160), and MRI revealed NBLs in 19% (25/131). On univariate analysis, the presence of MESs or MESs > 10 was not related to postoperative neurologic events or NBLs. On binary logistic regression analysis, MESs > 10 was not an independent predictor of NBLs (P=0.873, OR: 1.129, CI: 0.256 - 4.972). MESs were frequently found during CEA. However, they were not associated with NBLs.

Modifications in Near Infrared Spectroscopy for Cerebral Monitoring During Carotid Endarterectomy in Asymptomatic and Symptomatic Patients

To evaluate trends and differences in Near Infrared Spectroscopy (NIRS) monitoring during carotid endarterectomy (CEA) in patients affected by asymptomatic and symptomatic carotid artery stenosis, to predict postoperative neurological complications (PNCs). NIRS data of CEAs performed in a University Hospital were retrospectively reviewed. All the interventions were performed under general anesthesia and patients with intraoperative complications were excluded. Mean regional Oxygen Saturation Index (rSO2), pre-clamp values (mean baseline value, MBv and Single Mark Baseline value, SMBv) were collected and compared to the lowest rSO2 values during carotid cross-clamp (LSO2v) calculated within 3 min (percentage drop, PD). ROC curve analysis with Youden's Test was performed to determine the best threshold value of PD, in order to identify PNCs in both asymptomatic and symptomatic groups. Between 2007 and 2015, a total of 399 CEAs were consecutively performed with NIRS monitoring. Three-hundred-seventy-two CEAs in 355 patients were reviewed. Asymptomatic stenoses were 291 (81.9%), eleven (2.9%) PNC were registered (5 in asymptomatic and 6 in symptomatic group). Asymptomatic and symptomatic diseases had different MBv (69.5 ± 7.5 vs. 71.8 ± 6.9, respectively; P = 0.011) and similar rSO2 value during carotid clamping (63.7 ± 8.0 vs. 63.7 ± 6.7, respectively: P = 0.958). Asymptomatic patients experiencing PNCs had a greater PD than non-PNCs group (20.5 ± 10.2% vs. 12.5 ± 7.6%, respectively using MBv as baseline value; P=0.002), in contrast, in symptomatic patients, in which a low PD was associated with PNCs, it does not reach statistical significance (using MBv, 12.6 ± 5.4% vs. 14.8 ± 6.7%, respectively; P= 0.476). In order to detect PNCs, ROC analysis revealed an optimal PD cut-off value of -17% in asymptomatic CEAs. (Sensibility (Se) 0.80, Specificity (Sp) 0.76, PPV 0.05, NPV 0.99, Youden's index 0.56; P = 0.020) In symptomatic a threshold value of -9% was found, without reaching statistical significance. NIRS as cerebral monitoring during CEA can predict PNCs in asymptomatic stenosis. Asymptomatic and symptomatic groups differ in baseline and intraprocedural cut-off values to detect an augmented PNCs risk.

Carotid Endarterectomy

Carotid artery stenosis is associated with an elevated incidence of stroke, and carotid endarterectomy is performed to prevent future strokes in cases of severe carotid artery stenosis. Patients presenting for carotid endarterectomy often have a number of comorbidities that make them challenging to anesthetize. Both regional and general anesthetic techniques may be successfully used, but with either, careful management of hemodynamics throughout the perioperative course is critical. During carotid cross-clamping, it is important to monitor the patient’s neurologic status to ensure adequate perfusion to the ipsilateral hemisphere, and for this, a number of neuromonitoring modalities are available, with EEG monitoring being the most common. Several potential complications require close monitoring of the patient in the immediate postoperative period. This review contains 6 figures, 7 tables, and 49 references. Key Words: carotid artery stenosis, carotid endarterectomy, carotid artery stenting, cerebral hyperperfusion syndrome, cervical plexus block, electroencephalography, neck hematoma, neuromonitoring, preoperative optimization, stroke, transcranial Doppler

Carotid Cross-Clamp intolerance during carotid endarterectomy in regional anesthesia

During surgical endarterectomy, carotid cross clamping is needed for arteriotomy and plaque removal. Carotid cross clamping reduces the blood flow to the circle of Willis, and some patients show intolerance to the temporary occlusion of the internal carotid artery (ICA).&#x0D; Aim. This study demonstrates locoregional anesthesias safety in patients with carotid cross clamping intolerance (CCI) and the risk factors that predict this condition.&#x0D; Materials and Methods. All patients who underwent surgical carotid endarterectomy between January 2019 and December 2020 (n=53, 29 were male, age (median with range) 78 (56-90) years) were identified in a retrospective review. The indication for surgical treatment was made for a stenosed ICA of 70-99% or in the case of symptomatic stenosis.&#x0D; Surgical technique. An incision is made at the front edge of the sternocleidomastoid muscle. The common carotid artery (CCA) is identified and isolated from the surrounding tissues with sharp dissection and continued toward the bifurcation. Next, the internal and external carotid arteries can be isolated. Heparin (5000 U) is administrated intravenously, and the systolic arterial pressure is increased and kept over 160 mm Hg. In the next step, the cross clamping tolerance test is performed for 60 s. During clamping, the patient is neurologically meticulously observed. In the case of CCI, the operation proceeds with the insertion of a temporary shunt. The arteriotomy is started in the CCA and continues to the ICA. The plaque is completely removed, and the arteriotomy incision is covered with a patch. Before completing the suture, the clamps are partially removed to flush out the debris using the blood flow. Now, the external and common artery can be released. Finally, the clamp of the ICA can be removed.&#x0D; Results. Eight patients had cross clamping tolerance test intolerance. In all these cases, the surgical procedure was continued with a shunt. The further operation course remained uncomplicated. The in-hospital mortality was nil, and a transient ischemic attack occurred in only one case. Coronary artery disease (CAD) [odds ratio (OR) 12.65, 95% confidence interval (CI) 1.43-112.50], a history of cerebrovascular events [OR 10.50, 95% CI 1.83-60.30], and contralateral stenosis of 70% or more [OR 26.66, 95% CI 2.29-304.37] presented a significant association with the CCI and the need to shunt. The remaining factors showed no significant association with intolerance.&#x0D; Conclusions. Regional anesthesia is a safe method for identifying patients with CCI and safely performing the surgical procedure. Contralateral stenosis of the ICA and a history of cerebrovascular events are significant factors to predict CCI.

Impact of intraoperative neurologic deficits in carotid endarterectomy under regional anesthesia

Objective Patients undergoing carotid endarterectomy (CEA) may experiment neurologic deficits during the carotid cross-clamping due to secondary cerebral hypoperfusion. An associated risk of postoperative stroke incidence is also well established. This work aimed to assess the postoperative adverse events related to neurologic deficits in the awake test after clamping and to determine its predictive factors. Methods. From January 2012 to January 2018, 79 patients from a referral hospital that underwent CEA with regional anesthesia for carotid stenosis and manifested neurologic deficits were gathered. Consecutively selected controls (n = 85) were submitted to the same procedure without developing neurological changes. Postoperative complications such as stroke, myocardial infarction, all-cause death, and Clavien–Dindo classification were assessed 30 days after the procedure. Univariate and binary logistic regressions were performed for data assessment. Results. Patients with clamping associated neurologic deficits were significantly more obese than the control group (aOR = 9.30; 95% CI: 2.57–33.69; p = .01). Lower degree of ipsilateral stenosis and higher degree of contralateral stenosis were independently related to clamping intolerance (aOR = 0.70; 95% CI: 0.49–0.99; p = .047 and aOR = 1.30; 95% CI: 1.06–1.50; p = .009, respectively). Neurologic deficits were a main 30-day stroke predictor (aOR = 4.30; 95% CI: 1.10–16.71; p = .035). Conclusions. Neurologic deficits during carotid clamping are a predictor of perioperative stroke. Body mass index > 30 kg/m2, a lower degree of ipsilateral stenosis, and a higher degree of contralateral stenosis are independent predictors of neurologic deficits and, therefore, might play a role in the prevention of procedure-related stroke.

Efficacy of near-infrared spectroscopy cerebral oximetry on detection of critical cerebral perfusion during carotid endarterectomy under regional anesthesia.

Background: Patients undergoing carotid endarterectomy (CEA) may suffer from cerebral hypoperfusion during the carotid cross-clamping. Near-infrared spectroscopy cerebral oximetry (NIRS) is a non-invasive method of regional cerebral oxygen saturation measurement reflecting changes in cerebral blood flow during CEA. The main goal of the study was to evaluate the accuracy of the NIRS in detecting cerebral hypoperfusion during CEA under regional anesthesia (RA) and compare it with awake neurological testing. Patients and methods: A prospective observational study of 28 patients that underwent CEA in RA and manifested neurologic deficits, and 28 consecutive controls from a tertiary and referral center, was performed. All patients were monitored with NIRS cerebral oximetry and awake testing as the control technique. Subsequently, operating characteristic curve and Cohen's kappa coefficient were determined to evaluate the reliability of the monitoring test. Results: NIRS presented a sensitivity of 27.3% and a specificity of 89.3% in comparison to awake testing. Receiver operating characteristic (ROC) curve analysis demonstrated that a decrease of at least 20% in cerebral oxygen saturation is the best threshold to infer cerebral hypoperfusion. However, the respective area under the curve (AUROC) was 0.606 (95% CI: 0.456-0.756, P=0.178) with a calculated Cohen's kappa of 0.179, P=0.093. Regarding 30-days outcomes, only awake testing has shown significant associations with stroke and postoperative complications (P=0.043 and P=0.05), which were higher in patients with post-clamping neurologic deficits. Conclusions: NIRS demonstrated a reduced discriminative capacity for critical cerebral hypoperfusion, and does not seem to add substantial clinical benefits to the awake test.

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.

Application of near-infrared spectroscopy in carotid endarterectomy

Carotid endarterectomy (CEA) is effective treatment approach to prevent stroke in both symptomatic and asymptom-atic patients with carotid artery stenosis. However, cerebral hypoperfusion during carotid artery cross-clamping may lead to periopera-tive stroke, and nerve monitoring can be helpful in detection of cerebral ischemia, so as to take relevant treatment therapy. Near-infra-red spectroscopy (NIRS) measures the changes of regional cerebral oxygen saturation (rSO2) which can reflect intracranial perfusion, so as to determine the occurrence of cerebral ischemia. Its technique is simple and non-invasive, and can perform continuous and re-al-time monitoring during CEA. In this paper, the practicality and accuracy of various intraoperative neuro-monitoring techniques for CEA were analyzed in combination with the latest domestic and foreign studies in recent years. This paper focuses on various intraoper-ative neuro-monitoring techniques in CEA, the correlation between NIRS and other monitoring techniques, and the role of NIRS in pre-dicting intraoperative ischemia and postoperative hyperperfusion, which can further understand the clinical role of NIRS, so as to facili-tate its application in clinical setting. Key words: Carotid endarterectomy; Near-infrared spectroscopy; Cerebral ischemia; Cerebral oximetry; Cerebral hy-perperfusion syndrome

Purine Nucleosides as an Indicator of Cerebral Ischaemia in Local and General Anaesthetic Carotid Endarterectomy

Introduction: Neurological events, though rare, are a potential cause of significant morbidity in carotid endarterectomy (CEA). Shunting protects against ischaemic brain injury but is not without inherent risk to patients. In periods of cerebral ischaemia adenosine triphosphate (ATP) is metabolised, leading to accumulation of purine nucleosides. Purine measurements with an amperometric biosensor in patients undergoing CEA with loco-regional anaesthetic have shown a significant rise in purines on carotid cross clamping and subsequent returns to baseline on unclamping. This has proven the ability of this biosensor to allow real time measurements of purine nucleosides in vivo as a marker of developing cerebral ischaemia. The aim of this study was to determine the changes in purine concentrations intraoperatively in patients undergoing GA CEA Methods: CEA was performed in 18 Patients with Local anaesthetic (LA) and 40 patients under general anaesthetic (GA) at two teaching hospitals. 18 patients undergoing inguinal hernia repair were recruited as controls. Purines were measured from radial artery catheter samples at set time points throughout the procedure and recovery up to 24 hours post-operatively. Physiolgical parameters were measured peri-operatively. A selective shunt-patch policy was employed. The GA cohort were analysed in shunted and unshunted subgroups. Results: Physiological parameters between all groups were comparable although The LA cohort had a higher pulse during the clamped phase of CEA.. In the LA cohort there was a 2.8-fold increase in purines during the clamp phase (Median 2.4-6.7 mM). In the GA Cohorts there were no significant increases in purine concentrations on clamping (p=>0.05). There was also no significant difference in purine concentrations between shunted and unshunted GA subgroups during CEA (p=>0.05). The observed difference between GA and LA cohorts on application of the cross clamp was significant (P=0.004). The control cohort demonstrated no significant change in purines at any point. There were no perioperative or medium term neurological complications. Conclusion: These results demonstrate a significant rise in purines in the LA cohort during the clamp phase of CEA. This was not replicated in the GA cohort. This supports existing evidence that cerebral metabolic demand is higher during LA CEA than GA CEA. GA causes a significant decrease in cerebral metabolic rate and loss of metabolic rate-blood flow coupling that may result in “luxury perfusion” of cerebral tissue and subsequently little ischaemic nucleoside production intraoperatively. Previous studies have demonstrated rises in purines under GA with central venous sampling. Purines are inherently unstable in plasma and catabolism and/or reuptake may occur prior peripheral arterial sampling. Analysis of central venous samples may give greater sensitivity to changes in purines during GA CEA. Purines offer real time analysis of evolving brain ischaemia and as such, may aid surgeons with intraoperative decision making around shunting.

Impact of the Supra-Aortic Trunks and Circle of Willis Patency on the Neurological Compensation during Carotid Endarterectomy

One of the most critical phases of carotid endarterectomy (CEA) is the carotid cross-clamping test, which is a concrete evaluation of efficacy of collateral cerebral perfusion. Some studies revealed a strong correlation between tolerance to carotid cross-clamping and postoperative transient ischemic attack (TIA)/stroke complications. The aim of the study is to make a global analysis of supra-aortic trunks (SAT) and circle of Willis (CoW) patency to predict the tolerance to carotid cross-clamping preoperatively. We observed retrospectively 503 patients who underwent CEA under local anesthesia between January 2012 and 2017. We analyzed single preoperative risk factors, drug therapy, and vessels patency of the group of patients who did or did not present neurological symptoms at carotid cross-clamping. Afterward, we created a cerebral perfusion score (PTOT) to estimate the efficacy of collateral cerebral perfusion and we compared the results from both groups. The score ranges from 0 (hypothetical total occlusion of the SAT and CoW) to 0.65 in case of patency of all arterial districts. Moreover, we evaluated postoperative complication rates. Patients with previous neurological symptoms, female gender, and diabetes correlate with a lower tolerance to carotid cross-clamping (odds ratio: 2.57, 2.78, and 2.57, respectively; Pvalue<0.05). The SAT and CoW score revealed that patients with score <0.2 more frequently did not tolerate carotid cross-clamping (P value 0.01). Patients who required an intraoperative shunt presented a higher risk of TIA/stroke within 30days from surgery than those with a better neurological compensation (P value 0.03). The efficacy of cerebral mechanisms of compensation during carotid cross-clamping reflects the capability of the brain to adapt to ischemic insults, and this also correlates with the postoperative risk of TIA/stroke. It is possible to identify preoperatively patients with a higher risk of neurological intolerance at carotid cross-clamping. This score could be a useful method to make a further stratification of risk of neurological complications and eventually to prefer a general anesthesia and the use of shunt for those with PTOT < 0.2.

Carotid cross-clamping intolerance during carotid endarterectomy: the role of Willis' Circle variations

Carotid cross-clamping intolerance during carotid endarterectomy: the role of Willis' Circle variations

P07-8 - Arterial pressure management during carotid endarterectomy and neurological complications

Carotid endarterectomy (CEA) is the surgical treatment for patients with high-grade carotid artery stenosis performed, either under general anesthesia (GA) or regional anesthesia (RA) to reduce the risk of stroke (1). Intraoperative neurological assessment, especially during carotid cross-clamping is mandatory and can be easily realized under RA in the awake patient (2). The management of mean arterial pressure (MAP) during clamping in order to reduce risk of ischemic stroke is debated. Routine practice is to keep MAP ≥ 20% above baseline to optimize collateral cerebral blood flow (1). The primary objective of this retrospective study was to evaluate the risk of neurological complications depending on different levels of MAP during carotid cross-clamping under RA.

Risk and outcome profile of carotid endarterectomy with proximal intervention is concerning in multi-institutional assessment

ObjectiveApproaching tandem bifurcation and brachiocephalic disease using carotid endarterectomy (CEA) with ipsilateral proximal endovascular intervention (IPE) has been promulgated as safe and durable. There have been recent concerns about neurologic risk with this technique. The goal of this study was to define stroke and perioperative risk with this uncommon procedure across multiple centers. MethodsBetween August 2002 and July 2016, patients who underwent CEA + IPE were identified by operative records at three institutions. Primary end points were perioperative stroke and death, restenosis, freedom from neurologic event, and need for reintervention. Factors related to these end points were analyzed. ResultsThere were 62 patients who underwent CEA + IPE. The average age was 69 ± 9 years. Most were female 34 (55%); 56 (90%) were taking a statin and at least one antiplatelet agent. Bilateral internal carotid stenosis (>50%) was present in 32 (52%); 26 (42%) patients were symptomatic and 12 (19%) had undergone prior ipsilateral CEA. Bifurcation operations included longitudinal CEA/patch (38 [61%]), eversion CEA (20 [32%]), bypass graft (3 [5%]), and CEA/primary repair (1 [2%]). CEA was performed first in 53 (85%). All IPEs included stenting, with a single stent used in 58 (94%). Balloon-expandable stents were placed in the majority of patients (51 [82%]). Proximal arteries treated included the innominate (20 [32%]), left common carotid (32 [52%]), right common carotid (8 [13%]) and both innominate and right common carotid (2 [3%]). IPE was protected by carotid cross-clamp in 48 (77%). Shunting occurred in 14 (23%). There were four (6.5%) perioperative ipsilateral strokes and two hyperperfusion events. There were three (4.8%) operative deaths, one from stroke and two cardiovascular. Combined stroke and death rate was 11.3% and was not different between centers. Mean clinical follow-up was 6 ± 4 years. Mean imaging follow-up was 3 ± 4 years. Restenosis ≥50% at either intervention occurred in 20 (34%). Reintervention was performed for five proximal and three bifurcation failures (14%). Symptomatic status, redo operation, carotid clamp protection, multiple stents, and procedural order were not associated with operative stroke. Carotid clamp protection was associated with less restenosis (P = .003). Redo operation (P = .04) and hyperlipidemia (P = .05) were associated with reintervention. The 5-year actuarial survival was 81%, whereas freedom from stroke and reintervention were 94% and 81%, respectively. ConclusionsPerioperative stroke and death with CEA + IPE are substantial and consistent across centers. It is strikingly different from isolated CEA or CEA added to open brachiocephalic reconstruction. Restenosis is frequent, and reintervention at either the proximal stent or bifurcation is common. This technical strategy should be used cautiously and selectively reserved for those who are symptomatic with hemodynamically relevant tandem lesions and unfit for open revascularization.

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

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