Establishing a carotid artery stenosis disease cohort for comparative effectiveness research using natural language processing.

OBJECTIVE: Investigation of asymptomatic carotid stenosis treatment is hindered by the lack of a contemporary population-based disease cohort. We describe the use of natural language processing (NLP) to identify stenosis in patients undergoing carotid imaging. METHODS: Adult patients with carotid imaging between 2008 and 2012 in a large integrated health care system were identified and followed through 2017. An NLP process was developed to characterize carotid stenosis according to the Society of Radiologists in Ultrasound (for ultrasounds) and North American Symptomatic Carotid Endarterectomy Trial (NASCET) (for axial imaging) guidelines. The resulting algorithm assessed text descriptors to categorize normal/non-hemodynamically significant stenosis, moderate or severe stenosis as well as occlusion in both carotid ultrasound (US) and axial imaging (computed tomography and magnetic resonance angiography [CTA/MRA]). For US reports, internal carotid artery systolic and diastolic velocities and velocity ratios were assessed and matched for laterality to supplement accuracy. To validate the NLP algorithm, positive predictive value (PPV or precision) and sensitivity (recall) were calculated from simple random samples from the population of all imaging studies. Lastly, all non-normal studies were manually reviewed for confirmation for prevalence estimates and disease cohort assembly. RESULTS: A total of 95,896 qualifying index studies (76,276 US and 19,620 CTA/MRA) were identified among 94,822 patients including 1059 patients who underwent multiple studies on the same day. For studies of normal/non-hemodynamically significant stenosis arteries, the NLP algorithm showed excellent performance with a PPV of 99% for US and 96.5% for CTA/MRA. PPV/sensitivity to identify a non-normal artery with correct laterality in the CTA/MRA and US samples were 76.9% (95% confidence interval [CI], 74.1%-79.5%)/93.1% (95% CI, 91.1%-94.8%) and 74.7% (95% CI, 69.3%-79.5%)/94% (95% CI, 90.2%-96.7%), respectively. Regarding cohort assembly, 15,522 patients were identified with diseased carotid artery, including 2674 exhibiting equal bilateral disease. This resulted in a laterality-specific cohort with 12,828 moderate, 5283 severe, and 1895 occluded arteries and 326 diseased arteries with unknown stenosis. During follow-up, 30.1% of these patients underwent 61,107 additional studies. CONCLUSIONS: Use of NLP to detect carotid stenosis or occlusion can result in accurate exclusion of normal/non-hemodynamically significant stenosis disease states with more moderate precision with lesion identification, which can substantially reduce the need for manual review. The resulting cohort allows for efficient research and holds promise for similar reporting in other vascular diseases.

Intraoperative electroencephalographic changes during transcarotid artery revascularization are more frequent than previously reported.

OBJECTIVE: Up to 14% of patients undergoing carotid endarterectomy with continuous electroencephalographic (EEG) neuromonitoring will require shunt placement because of EEG changes. However, the initial studies of transcarotid artery revascularization (TCAR) found only one patient with temporary EEG changes. We report our experience with intraoperative EEG monitoring during TCAR. METHODS: We conducted a retrospective review of patients who underwent TCAR at two urban hospitals within an integrated healthcare network from May 2017 to January 2020. The data included demographic information, patient comorbidities, symptom status, previous carotid interventions, anatomic details, contralateral disease, intraoperative vital signs and EEG changes, and postoperative major adverse events (transient ischemic attack, stroke, myocardial infarction [MI], and death) both initially and at 30 days postoperatively. The Fisher exact test was used for categorical data and the Wilcoxon rank sum test for continuous data. RESULTS: A total of 89 patients underwent TCAR during the study period, of whom 71 (79.8%) received intraoperative EEG neuromonitoring. Of the 89 patients, 70.8% were men and 29.2% were women. The median age was 75 years (IQR, 68-82.5 years). Symptomatic patients accounted for 41.6% of the cohort. Of the 71 patients who received continuous neuromonitoring, 9 experienced EEG changes during TCAR (12.7%). The changes resolved in seven patients with pressure augmentation in three and switching to a low flow toggle in three. One patient who had sustained EEG changes had a new postoperative neurologic deficit. The median carotid stenosis percentage on preoperative computed tomography angiography was lower for patients with EEG changes than for those without (67% vs 80%; P = .01). No correlation was found between symptom status or 30-day stroke in patients with and without EEG changes (P = .49 and P = .24, respectively). Overall, three postoperative strokes, two postoperative deaths, and one MI occurred, for a composite 30-day stroke, death, and MI rate of 6.7%. CONCLUSIONS: Changes in continuous EEG monitoring were more frequent in our study than previously reported. Less severe carotid stenosis might be associated with a greater incidence of EEG changes. Limited data are available on the prognostic ability of EEG to detect clinically relevant changes during TCAR, and further studies are warranted.

Anesthetic considerations in transcarotid artery revascularization.

Transcarotid artery revascularization is a relatively new technology made available to vascular interventionalists within the last several years for patients with carotid artery stenosis. However, the intraoperative techniques and perioperative management of these patients continues to evolve as more experience is gained. Herein, we consider some important principles of anesthesia for patients undergoing this procedure.

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

BACKGROUND: Although 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. METHODS: We 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. RESULTS: The 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. CONCLUSIONS: The 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.

Impact of cerebral large-artery disease and blood flow in the posterior cerebral artery territory on cognitive function.

OBJECTIVES: The purpose of this study was to elucidate the association of cerebral large artery disease (CLAD) with cerebral blood flow (CBF) in the posterior cerebral artery (PCA) territory and cognitive performance. METHOD: We prospectively registered patients with CLAD who had internal carotid or middle cerebral artery (MCA) with the degree of stenosis ≥50%. Automated brain segmentation was used to quantify CBF in the thalamus, hippocampus, and PCA and MCA territories. We measured cognitive function of patients using the Wechsler Memory Scale Revised (WMS-R), the Mini-Mental State Examination (MMSE), and the Montreal Cognitive Assessment. Patients were divided into 3 groups according to CBF of the cortical and subcortical PCA territory. RESULTS: There were 60 patients included in this study. The degree of stenosis was significantly correlated with CBF in the PCA territory (Γ = 0.35, P = .006) and hippocampus (Γ = 0.34, P = .008). Verbal memory, general memory, and reproduction on WMS-R and MMSE were significantly reduced areas with low CBF in the PCA territory compared with areas with middle and high CBF. CONCLUSIONS: CBF of the PCA territory was significantly inversely correlated with the degree of stenosis in CLAD patients. Low CBF of the PCA territory was significantly associated with reduced cognitive and memory functions.

Huoluo Yinao decoction mitigates cognitive impairments after chronic cerebral hypoperfusion in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Huoluo Yinao decoction (HLYND) has been used to ameliorate cognitive impairment induced by chronic cerebral hypoperfusion in clinical for years. However, the exact mechanisms remain unknown. AIM OF THE STUDY: To investigate the effects and mechanisms underlying HLYND-mediated improvement in cognitive deficits associated with chronic cerebral hypoperfusion. MATERIALS AND METHODS: Thirty-six Sprague-Dawley rats were randomly allocated to three groups: sham, model, and HLYND. Daily administration of HLYND or volume-matched vehicle by gavage was initiated 1 day after bilateral carotid artery stenosis (BCAS) and continued for 42 days. The Morris water maze (MWM) test was used to assess cognitive functions from days 36-42. Via western blot and immunofluorescent staining, restoration of neuronal plasticity and remyelination of white matter were evaluated by analyzing the expression profiles of MAP-2, synaptophysin and MBP. In addition, macrophage/microglial activation was assessed by quantifying changes in Iba1, and macrophage/microglial polarization was assessed by changes in iNOS and CD16 (M1 markers), as well as Arg1 and CD206 (M2 markers). RESULTS: In the MWM test, BCAS rats showed significantly extended escape latency and reduced platform crossing times, while those in the HLYND group had shortened escape latency and increased frequency of platform crossing. In addition, rats in the model group showed decreased levels and abnormal morphological changes of MAP-2, synaptophysin and MBP, whereas HLYND administration reversed these effects. As expected, Iba1 levels were elevated in both the model and HLYND groups but rats in the model group showed increased levels of the M1 markers, iNOS and CD16, and a correspondent decrease in the M2 marker, Arg1. In contrast, in the HLYND group, iNOS and CD16 levels were suppressed, while Arg1 levels were elevated. CONCLUSIONS: Our findings demonstrate that HLYND mitigates cognitive impairment after chronic cerebral hypoperfusion in rats through mechanisms involving increased neuronal plasticity and white matter remyelination, with a subtile modulation of macrophage/microglial polarization toward the M2 phenotype.

Ginkgo biloba L. extract protects against chronic cerebral hypoperfusion by modulating neuroinflammation and the cholinergic system.

BACKGROUND: Ginkgo biloba extract (GBE)-a widely used nutraceutical-is reported to have diverse functions, including positive effects on memory and vasodilatory properties. Although numerous studies have assessed the neuroprotective properties of GBE in ischemia, only a few studies have investigated the neuro-pharmacological mechanisms of action of GBE in chronic cerebral hypoperfusion (CCH). PURPOSE: In the present study, we sought to determine the effects of GBE on CCH-induced neuroinflammation and cholinergic dysfunction in a rat model of bilateral common carotid artery occlusion (BCCAo). METHODS: Chronic BCCAo was induced in adult male Wistar rats to reflect the CCH conditions. On day 21 after BCCAo, the animals were treated orally with saline or GBE (5, 10, 20, and 40mg/kg) daily for 42 days. After the final treatment, brain tissues were isolated for the immunohistochemical analysis of glial markers and choline acetyltransferase (ChAT), as well as for the western blot analysis of proinflammatory cytokines, toll-like receptor (TLR)-related pathway, receptor for advanced glycation end products (RAGE), angiotensin-II (Ang-II), and phosphorylated mitogen-activated protein kinases (MAPKs). RESULTS: BCCAo increased glial proliferation in the hippocampus and white matter, whereas proliferation was significantly attenuated by GBE treatment. GBE also attenuated the BCCAo-related increases in the hippocampal expression of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6), TLR4, myeloid differentiation primary response gene 88, RAGE, Ang-II, and phosphorylated MAPKs (ERK, p38, and JNK). Furthermore, GBE treatment restored the ChAT expression in the basal forebrain following BCCAo. CONCLUSIONS: These findings suggest that GBE has specific neuroprotective effects that may be useful for the treatment of CCH. The pharmacological mechanism of GBE partly involves the modulation of inflammatory mediators and the cholinergic system.

Carotid surgery in private practice: what kind of change in the last 15 years?

BACKGROUND: This retrospective study analyzes and compares the results of patients undergoing carotid endarterectomy (CE) for atherosclerotic stenosis obtained by 2 surgeons during two 5-year periods. Group 1 (G1) represents the first period (January 1994-December 1998) and group 2 (G2) represents the second period (January 2006-December 2010). Our objective was to answer the 2 following questions: (1) Has the population changed between these 2 periods with regard to age, risk factors, and symptoms? (2) Have the techniques we used in G2--local anesthesia and eversion technique--improved the results? METHODS: G1 included 682 CE procedures on 610 patients and G2 included 629 procedures on 592 patients. The following factors were analyzed in G1 and G2: distribution of age and sex, the main risk factors (diabetes and cardiovascular risk), symptomatology, the degree of stenosis, the preoperative computed tomography (CT) data, the type of anesthesia (general or local), the use of an intraoperative shunt, surgical techniques, postoperative patency, cardiac complications, central and peripheral neurologic complications, and reoperations. In conformity with the North American Symptomatic Carotid Endarterectomy Trial classifications, stenosis of >70% was included in this survey. Loops, tumors, aneurysms, and restenosis were excluded. Heparin (300 U.I./kg) was administered. Shunt placing was selective. The 3 most common techniques used were eversion, longitudinal CE with patch angioplasty, and CE with direct closure. Postoperative patency was controlled by intravenous digital angiography or duplex ultrasonography. Follow-up occurred until postoperative day 30. RESULTS: Compared with G1, the incidence of arterial hypertension, diabetes, and coronary atherosclerosis treated by angioplasty increased significantly in G2; local anesthesia replaced general anesthesia in G2, and fewer intraoperative shunts were used (P = 0.034). The technique of direct closure of the arteriotomy was no longer used. In contrast to G1, in G2 no postoperative carotid thromboses (P = 1.8) and no lethal strokes (P = 5.44) were observed. The incidence of major adverse cardiovascular events on postoperative day 30 was 1.7% in G1 compared with 0.79% in G2. The combined mortality and morbidity rate--including reoperations and peripheral neurologic deficits--was 3.95% in G1 compared with 3.81% in G2. CONCLUSION: Despite a major increase in risk factors, the combined use of local anesthesia and eversion technique, when technically feasible, improved our results in G2.

Cardiotonic pill attenuates white matter and hippocampal damage via inhibiting microglial activation and downregulating ERK and p38 MAPK signaling in chronic cerebral hypoperfused rat.

BACKGROUND: The cardiotonic pill (CP) is a herbal medicine composed of Salvia miltiorrhiza (SM), Panax notoginseng (PN), and Dryobalanops aromatica Gaertner (DAG) that is widely used to treat cardiovascular diseases. The present experiment was conducted to examine the effects of CP on white matter and hippocampal damage induced by chronic cerebral hypoperfusion. METHODS: Chronic cerebral hypoperfusion was induced in male Wistar rats by permanent bilateral common carotid artery occlusion (BCCAo). Daily oral administration of CP (200 mg/kg) began 21 days after BCCAo and continued for 42 days. The levels of microglial activation and myelin basic protein (MBP) were measured in the white matter and hippocampus of rats with chronic BCCAo, and the expression levels of mitogen-activated protein kinases (MAPKs) and inflammatory markers such as cyclooxygenase-2, interleukin-1ß, and interleukin-6 were examined. RESULTS: MBP expression was reduced in the white matter and hippocampal regions of rats that received BCCAo. In contrast, reduced levels of MBP were not observed in BCCAo rats given CP treatments. The administration of CP alleviated microglial activation, the alteration of ERK and p38 MAPK signaling, and inflammatory mediator expression in rats with chronic BCCAo. CONCLUSION: These results suggest that CP may have protective effects against chronic BCCAo-induced white matter and hippocampal damage by inhibiting inflammatory processes including microglial activation and proinflammatory mediator expression, and downreguating the hyperphosphorylation of ERK and p38 MAPK signaling.

Neurocognitive changes after eversion carotid endarterectomy under local anesthesia.

BACKGROUND: The effects of carotid endarterectomy (CEA) on cognitive function have yet to be fully elucidated. The aim of our study was to administer a battery of cognitive tests to identify any cognitive changes occurring in a consecutive series of patients who underwent CEA using the eversion technique under local anesthesia. METHODS: This prospective study was designed to analyze a consecutive series of patients undergoing eversion CEA under local anesthesia for significant carotid stenosis at our vascular surgery unit over a period of 6 months. Patients underwent tests to rule-out those who already had cognitive impairments or states of depression/anxiety capable of interfering with cognitive testing outcomes. Patients then completed a battery of 10 neurocognitive tests preoperatively and again 30 days and 4 months after surgery to assess the functions of both cerebral hemispheres as thoroughly as possible. RESULTS: Of the 48 patients initially considered for our study, 39 completed the follow-up. They were 71.4 ± 8.2 (mean ± SD) years of age; 30 were men and 9 were women. Six were symptomatic for carotid stenosis and 33 were asymptomatic. All patients were examined by a neurologist and underwent pre- and postoperative nuclear MRI or CT scan of the brain to identify any cerebral ischemia potentially correlated with the surgical procedure. In all cases, the cognitive test findings tended to improve postoperatively; this improvement was statistically significant in 7 tests. Post-hoc analysis confirmed an improvement between the pre- and postoperative test results. Among the different variables considered, only age <75 years seems to have influenced cognitive improvement. CONCLUSIONS: The effects on cognitive function of carotid stenosis, particularly CEA, is still a much debated issue. The data reported in the literature vary considerably, preventing any final conclusions from being drawn. The mechanisms capable of inducing changes in cognitive status after CEA have yet to be precisely clarified. In our study, a suitable battery of tests were used to analyze the trend of cognitive function correlating with eversion CEA under local anesthesia. Our results demonstrate substantially improved cognitive function after CEA, which was statistically significant in 7 of 10 tests. We surmise that the CEA procedure, per se, can help to protect patients against cognitive deterioration, especially in those <75 years of age.

Reperfusion does not improve impaired rapid-onset cortical plasticity in patients with severe stenosis of the internal carotid artery.

BACKGROUND: Severe stenosis of the internal carotid artery (ICA) has been associated with impaired cognition in patients, but its effect on rapid-onset cortical plasticity is not known. Carotid endarterectomy (CEA) in patients with severe ICA stenosis reduces stroke risk, but the impact on cognition or physiology of the respective hemisphere remains controversial. METHODS/RESULTS: 16 patients with severe stenosis of the ICA and 16 age and sex matched controls were included. Rapid-onset cortical plasticity was assessed using the paired-associative stimulation (PAS) protocol. PAS models long-term synaptic potentiation in human motor cortex, combining repetitive stimulation of the peripheral ulnar nerve with transcranial magnetic stimulation of the contralateral motor cortex. Cognitive status was assessed with a neuropsychological test battery. In patients, verbal learning and rapid-onset cortical plasticity were significantly reduced as compared to controls. Identical follow-up tests in 9 of the 16 patients six months after CEA revealed no improvement of cognitive parameters or cortical plasticity. CONCLUSIONS: Decreased rapid-onset cortical plasticity in patients with severe stenosis of the ICA was not improved by reperfusion. Thus, other strategies known to increase plasticity should be tested for their potential to improve cortical plasticity and subsequently cognition in these patients.

Optimising conditions for studying the acute effects of drugs on indices of cardiac contractility and on haemodynamics in anaesthetized guinea pigs.

INTRODUCTION: Detecting adverse effects of drugs on cardiac contractility is becoming a priority in pre-clinical safety pharmacology. The aim of this work was to optimise conditions and explore the potential of using the anaesthetized guinea pig as an in vivo model. METHODS: Guinea pigs were anaesthetized with Hypnorm/Hypnovel, isoflurane, pentobarbital or fentanyl/pentobarbital. The electrocardiogram (ECG), heart rate, arterial blood pressure and indices of cardiac contractility were recorded. In further experiments in fentanyl/pentobarbital anaesthetized guinea pigs the influence of bilateral versus unilateral carotid artery occlusion on haemodynamic responses was investigated and the effects of inotropic drugs on left ventricular (LV) dP/dt(max) and the QA interval were determined. RESULTS: Pentobarbital, given alone or after fentanyl, provided suitable anaesthesia for these experiments. Bilateral carotid artery occlusion did not alter heart rate or arterial blood pressure responses to isoprenaline or angiotensin II. Isoprenaline and ouabain increased LVdP/dt(max) and decreased the QA interval whereas verapamil had opposite effects and strong inverse correlations between LVdP/dt(max) and the QA interval were found. DISCUSSION: Conditions can be optimised to allow the pentobarbital-anaesthetized guinea pig to be used for simultaneous measurement of the effects of drugs on the ECG, haemodynamics and indices of cardiac contractility. The use of this small animal model in early pre-clinical safety pharmacology should contribute to improvements in detecting unwanted actions on the heart during the drug development process.

[Oxygen provision of the brain during carotid endarterectomy in the settings of general and local anaesthesia].

Based on the indices of cerebral oximetry, analysed herein is efficiency of oxygen support of the brain in various types of anaesthesiological provision (total and general anaesthesia) in patients presenting with atherosclerosis of the brachiocephalic arteries during carotid endarterectomy. It was shown that at the expense of preserving the mechanism of autoregulation, the use of local anaesthesia provides higher efficiency of cerebral perfusion than general anaesthesia which is evidenced by the values of cerebral oximetry exceeding 60% at all stages of the operation. Dynamics of cerebral oxygenation during occlusion of the carotid arteries in the setting of local anaesthesia suggests high reactivity of the cerebral vessels in this cohort of patients and hence preservation of the cerebrovascular reserve in them.

Effect of carotid sinus nerve blockade on hemodynamic stability during carotid endarterectomy under local anesthesia.

OBJECTIVE: To find out whether routine carotid sinus nerve blockade with lidocaine during carotid endarterectomy under local anesthesia results in perioperative changes in blood pressure and heart rate. METHODS: This was a prospective, randomized, single-center study, conducted in a university hospital. A total of 120 patients undergoing carotid endarterectomy under local anesthesia were randomly assigned to three equal groups. Patients with previous carotid endarterectomy were excluded from the study. During the operation the carotid sinus area was infiltrated as follows: group 1 received 2 mL of 1% lidocaine; group 2 received 2 mL of 0.9% NaCl; and group 3 received no infiltration. The carotid sinus nerve was spared in all patients. Blood pressure and heart rate were invasively monitored during the operation and 12 hours postoperatively over the radial artery cannula. Preoperative values were calculated as a mean of three noninvasive measurements on the day before surgery. Data comprised of arterial blood pressures and heart rates from 32 time point measurements for each patient were analyzed. RESULTS: There was no significant difference among the groups regarding the mean arterial blood pressures and mean heart rates during the follow-up period. There was no significant difference among groups regarding the number of patients that required vasoactive therapy at any time of measurement. CONCLUSION: Routine infiltration of carotid sinus area with 1% lidocaine during carotid endarterectomy performed under local anesthesia has no significant impact on mean arterial blood pressure and heart rate during the operative procedure and the following 12 postoperative hours.

The role of cerebral oximetry in combination with awake testing in patients undergoing carotid endarterectomy under local anaesthesia.

INTRODUCTION: The aim of this study is to analyse the role of cerebral oximetry in combination with awake testing in detecting cerebral ischaemia in patients undergoing carotid endarterectomy (CEA) under local anaesthesia (LA). METHODS: One hundred consecutive patients scheduled for CEA under LA were investigated. Regional oxygen saturation (rSO(2)) was measured with a cerebral oximeter. Cerebral ischaemia was assessed by awake testing in conjunction with rSO(2). Shunting was based solely on deterioration in conscious state assessed by awake testing. The correlation between awake testing and percentage fall in rSO(2) levels was statistically analysed. RESULTS: Patients requiring general anaesthesia were excluded from analysis (n = 17). Seven patients developed deterioration in conscious state and an immediate drop in rSO(2) ≥20% following carotid cross-clamping. Two patients requiring shunting for non-neurological reasons were excluded from analysis. Two patients had a drop in rSO(2) ≥20%, but remained conscious and were not shunted. There were no permanent neurological deficits postoperatively. Statistical analysis showed a sensitivity of 100% with a specificity of 96% yielding a positive predictive value of 81% and negative predictive value of 100% for a ≥19% drop in rSO(2). CONCLUSION: Cerebral oximetry using a cut off ≥19% drop in rSO(2) has a high sensitivity and specificity when compared with awake testing.

Cerebral monitoring in patients undergoing carotid endarterectomy using a triple assessment technique.

OBJECTIVES: Selective shunting during carotid endarterectomy (CEA) is advocated to reduce shunt related stroke. Cerebral monitoring is essential for temporary carotid shunting. Many techniques are available for cerebral monitoring, however, none is superior to monitoring the patient's neurological status (awake testing) while performing the procedure under local anaesthesia (LA). Cerebral oximetry (CO) and trans-cranial Doppler (TCD) has previously been used to show the adequacy of cerebral circulation in patients undergoing CEA. The aim of this study is to assess the reliability of CO and TCD in predicting the need for shunting compared to the awake testing. METHODS: Patients scheduled for CEA under LA were included. Patients converted to general anaesthesia (GA) and patients with no TCD window were excluded from the study. The Somanetics INVOS(®) CO was used for ipsilateral cerebral monitoring in all patients, in addition to TCD and awake testing. The percentage fall in CO regional oxygen saturation (rSO(2)), and decline in the mean flow velocity (FVm) in TCD following carotid artery clamping recorded. A drop in rSO(2) of ≥20% or FVm of ≥50% was considered an indicator of cerebral ischaemia that may predict the need for carotid shunting. Patients only shunted based on awake testing. RESULTS: Forty-nine patients underwent triple assessment. The median clamp time was 24 min. 8/49 patients (16.3%) needed carotid shunting based on awake testing. In this group, six patients had ≥20% drop in rSO(2), and ≥50% drop in FVm. However, two patients had a non-significant drop in both rSO(2) and FVm (false negative). In the non-shunted group (41/49), one patient had a significant drop in rSO(2) (false positive) while 10/41 patients had a >50% drop in FVm. This represents sensitivity of 75%, and specificity of 97.5% for CO compared to sensitivity of 75% and specificity of 75% for TCD in prediction of shunting. The positive predictive value and negative predictive value were 85.7 and 95.2%, respectively for CO, compared to 37.5 and 93.9% for TCD. CONCLUSIONS: TCD is less accurate than CO in predicting the need for carotid shunting during CEA. A combination of both methods does not add to the accuracy of detecting the need for carotid shunting.

The effects of acarbose treatment on intimal hyperplasia in a rat carotid endarterectomy model of diet-induced insulin resistance.

BACKGROUND: Increased carotid restenosis due to revascularization therapy is associated with insulin resistance. We hypothesize that glucose control using acarbose may attenuate intimal hyperplasia in rat carotid endarterectomy model of diet-induced insulin resistance. METHODS: Rats were fed low-fat complex carbohydrate (control) or high-fat sucrose (insulin resistance) for 4 months. Three days preoperatively, some high-fat-sucrose rats were on acarbose, remainder of the rats received placebo. Rat carotids were assessed with duplex pre-and postoperatively. Acarbose and placebo continued for 2 weeks. Glucose, insulin, blood flow velocities and intimal hyperplasia were determined. RESULTS: High-fat sucrose plus acarbose attenuated intimal hyperplasia. Post-drug high-fat sucrose glucose decreased. Blood flow velocities postoperatively elevated above baseline. High-fat sucrose increased blood flow velocities postoperatively, which was attenuated with acarbose. CONCLUSION: Glucose control by acarbose in rat carotid endarterectomy model of diet-induced insulin resistance resulted in attenuation of intimal hyperplasia.

Postoperative internal carotid artery restenosis after local anesthesia: presence of risk factors versus intraoperative shunt.

Published data suggest that the regional anesthetic technique used for carotid endarterectomy (CEA) increases the systolic arterial blood pressure and heart rate. At the same time local anesthesia reduced the shunt insertion rate. This study aimed to analyze risk factors and ischemic symptomatology in patients with postoperative internal carotid artery restenosis. The current retrospective study was undertaken to assess the results of CEA in 8000 patients who were operated during a five-year period in six regional cardiovascular centers. Carotid color coded flow imaging, medical history, clinical findings and atherosclerotic risk factors were analyzed. Among them, there were 33 patients (0.4%) with postoperative re-occlusion after CEA. The patients with restenosis were re-examined with carotid color coded flow imaging and data were compared with 33 consecutive patients with satisfactory postoperative findings to serve as a control group. In the restenosis group eight risk factors were analyzed (hypertension, smoking, hyperlipidemia, diabetes mellitus, history of stroke, transitory ischemic attack, heart attack and coronary disease), and compared with risk factors in control group. Study results suggested that early postoperative internal carotid artery restenosis was not caused by atherosclerosis risk factors but by intraoperative shunt usage.

Combined 1H and 31P MR spectroscopic imaging: impaired energy metabolism in severe carotid stenosis and changes upon treatment.

OBJECT: To evaluate if combined (1)H and (31)P MR spectroscopic imaging (MRSI) before and after treatment of severe internal carotid artery (ICA) stenosis detects significant changes in energy metabolism in the basal ganglia of both hemispheres. MATERIALS AND METHODS: A group of 14 patients with high-grade ICA stenosis and 11 healthy control subjects were examined with 2D (1)H MRSI and 3D (31)P MRSI at 3 T before and after treatment of severe ICA stenosis. Spectroscopic data were processed with LCModel and jMRUI software. Changes of the phosphorylated metabolites, pH, N-acetyl-acetate, creatine and choline-containing compounds prior/post intervention were analyzed and patients' data were compared with that of control subjects. RESULTS: Untreated patients had significantly higher Adenosindiphosphate (ADP) in basal ganglia ipsi- and contralateral to the side of ACI stenosis compared to controls. After treatment, ADP of both hemispheres significantly decreased by approximately 20% compared to the pre-treatment values. Further, significant decreases of phosphorylated metabolites prior/post intervention were found for patients compared to controls. CONCLUSION: This spectroscopic study reveals that unilateral high-grade ICA stenosis has an effect on cerebral high-energy metabolism of both hemispheres, which is at least partially reversible after treatment. Therefore the restoration of blood flow in high-grade ICA stenosis recovers the impaired energy balance of the brain.