Internal Carotid Artery Stenosis In Patients Research Articles

A Novel Staged Revascularization Strategy for Bilateral Severe Internal Carotid Artery Stenosis at High Risk for Hyperperfusion Syndrome

Since bilateral severe internal carotid artery stenosis often is associated with severely decreased cerebrovascular reactivity (CVR) due to poor collateral blood flow, revascularization carries a high risk for development of hyperperfusion syndrome. In this study, we report a new staged strategy to prevent postoperative hyperperfusion syndrome in such patients. Bilateral severe cervical internal carotid artery stenosis patients with decreased CVR to 10% or less on one side were prospectively enrolled in this study. We first performed carotid artery stenting on the side with the milder CVR decrease (lower-risk side), aiming to improve hemodynamics associated with the severe CVR decrease on the greater-risk side. Then, carotid endarterectomy or carotid artery stenting was performed on the contralateral side after an interval of 4-8 weeks. In all 3 cases enrolled in this study, CVR on the greater-risk side improved to 10% or more 1 month after the first treatment. The ratio of regional cerebral blood flow on the contralateral greater-risk side was 114% 1 day after the second treatment, and HPS did not develop in any of the cases. Our treatment strategy, in which revascularization on the lower-risk side precedes that on the greater-risk side, is effective for the prevention of HPS in bilateral ICA stenosis patients.

Abstract TMP66: Correlation Of Cerebrovascular Reserve Assessed By Acetazolamide-stress Spect With Collaterals On Arterial Spin-labeling MRI In Patients With Carotid Occlusive Disease

Introduction: We investigated the relationship between the level of cerebral collateral circulation on arterial spin-labeling (ASL) magnetic resonance imaging (MRI) and cerebrovascular reserve (CVR) on acetazolamide (ACZ)-stress single photon emission computed tomography (SPECT) brain scans in internal carotid artery (ICA) stenosis. Methods: This study enrolled 129 patients with severe ICA stenosis (>70%). Collateral circulation was assessed in pulsed ASL images based on the presence of arterial transit artifact (ATA) that late-arriving flow appears as serpiginous high ASL signal within cortical vessels. CVR based on rest-SPECT and ACZ-stress SPECT with Tc-99m-ECD was calculated. The ASL CBF maps were independently assessed by two neuroradiologists blinded to clinical information. The two neuroradiologists graded on two slices of ASL images corresponding to Alberta Stroke Program Early Computed Tomography Score (ASPECTS) location using a 4-point scale for ASL intensity. Results: With ACZ-stress SPECT, the 88/129 (68%) patients showed normal CVR and 41/129 (32%) patients showed decreased CVR. In 73/88 (82%) of the normal CVR group patients, ASL showed ATA in ipsilateral to the stenosis. In 19/41 (46%) of the decreased CVR group patients, ASL showed no evidence of ATA in ipsilateral to the stenosis. Significant positive relationship was observed between the normal CVR group and the ATA showing group in ICA stenosis patients (p = 0.001, chi-square test). The ASL-based ASPECTS scores of brain in the ipsilateral side was lower than the scores in the contralateral side to the ICA stenosis (p < 0.0001, Wilcoxon signed rank test). The ASL-based ASPECTS scores of brain ipsilateral side to the ICA stenosis was lower in the reduced CVR group than normal CVR group (p = 0.005). Conclusion: This study demonstrated the statistically significant positive correlation between good collaterals on ASL MRI and intact CVR in patients with ICA stenosis.

Correlation between unilateral internal carotid artery stenosis and asymmetric distribution of enlarged perivascular spaces in patients with acute cerebral infarction

Objective: To explore the correlation between unilateral internal carotid artery (ICA) stenosis and asymmetrical distribution of enlarged perivascular spaces (EPVS) in patients with acute cerebral infarction. Methods: Acute cerebral infarction patients with unilateral ICA stenosis hospitalized in Changzhou Second People's Hospital from October 2020 to December 2021 were collected. Routine cranial MRI and CT angiography were completed for each patient. The 3D Slicer software was used to quantitatively analyze the volume of patient's EPVS. Patients were divided into moderate stenosis group and severe stenosis/occlusion group according to the degree of ICA stenosis. Baseline data were compared between the two groups. Patients were further divided into three groups: moderate stenosis, severe stenosis and occlusion groups, and the ipsilateral and contralateral EPVS volume of ICA stenosis patients was compared. The asymmetry index (AI) was calculated for EPVS in the basal ganglia region (BG-EPVS) and EPVS in the centrum semiovale (CSO-EPVS). Patients with AI≥0.2 were included in the EPVS asymmetry group, while the rest were in the EPVS symmetry group, and the degree of unilateral ICA stenosis was compared between the two groups. Multivariate logistic regression model was used to analyze the relationship between ICA severe stenosis/occlusion and the asymmetric distribution of BG-EPVS. Results: A total of 122 patients (96 males and 26 females) were enrolled, aged (70±10) years, with 81 cases in the unilateral ICA severe stenosis/occlusion group (46 cases of severe stenosis and 35 of occlusion) and 41 cases in the moderate stenosis group. Patients in the unilateral ICA severe stenosis/occlusion group had greater BG-EPVS volume [(4.08±0.76) mm3]and proportion of asymmetric distribution of BG-EPVS [75.3%(61/81)] than those of the moderate stenosis group [(3.12±0.85) mm3 and 39.0% (16/41)], with statistically significant differences (both P<0.001). The BG-EPVS volumes of the ipsilateral side of the stenosis in the severe stenosis group and the occlusion group [(3.34±0.86) mm3 and (3.93±0.60) mm3] were significantly greater than those of the contralateral side [(2.65±1.28) mm3 and (3.21±0.88) mm3], with statistically significant differences (both P<0.001). Correlation analysis indicated that the degree of unilateral ICA stenosis was positively correlated with the BG-EPVS volume on the stenosis side (r=0.62, P<0.001). Further comparison of the degree of unilateral ICA stenosis between the EPVS symmetric and asymmetric groups showed that the proportion of unilateral ICA severe stenosis/occlusion in the BG-EPVS asymmetry group was higher than that in the symmetric group [79.2%(61/77) vs 44.4%(20/45),P<0.001]. Multivariate logistic regression analysis showed that unilateral ICA severe stenosis/occlusion (OR=4.280, 95%CI: 1.743-10.508, P =0.002) and age (OR=1.055, 95%CI: 1.001-1.112, P=0.044) were risk factors for asymmetric distribution of BG-EPVS. Conclusions: The severe stenosis/occlusion of the unilateral ICA and age are the risk factors for the asymmetric distribution of the BG-EPVS in patients with acute cerebral infarction. The ipsilateral EPVS volume of unilateral ICA stenosis is larger than that of the contralateral side, and the degree of ICA stenosis is positively correlated with the severity of BG-EPVS.

Prevalence of carotid artery stenosis with coronary artery disease in Japanese patients: A single-center study

There are a few reports of the prevalence of extracranial internal carotid artery stenosis (ICAS) in Asian patients with coronary artery disease (CAD). This was a prospective registry study of 157 consecutive Japanese patients undergoing coronary angiography that aimed to determine the prevalence of extracranial ICAS in recent Japanese patients. The associations between ICAS and the extent or the maximal stenosis of CAD were also investigated. The 131 eligible patients with suspected CAD were prospectively analyzed. Their mean age was 69.0 ± 8.2 years, and 75.6% were males. A total of 111 patients (84.7%) were angiographically diagnosed with CAD. ICAS (area stenosis ≥50% on ultrasonography) was present in 9 patients, and the prevalence in patients with CAD was 8.1%. All patients in the ICAS group had CAD, and this group was significantly more likely to have a history of stroke (p = 0.03). Although no significant relationships were found between the severity of ICAS and the maximal stenosis of CAD, the severity of ICAS increased gradually with the extent of CAD. The prevalence of ICAS in patients with CAD treated with current medical treatment was relatively low (8.1%) compared to previous reports, and the severity of ICAS was significantly associated with the extent of CAD.

Quantitative assessment of retinal vessel density and thickness changes in internal carotid artery stenosis patients using optical coherence tomography angiography

ObjectiveTo quantitatively assess the retinal features of patients with different degrees of internal carotid artery stenosis (ICAS), particularly mild ICAS patients, utilizing optical coherence tomography angiography (OCTA). MethodsThirty-two mild ICAS patients (mild ICAS group), 34 moderate to severe ICAS patients (nonmild ICAS group), and 40 controls were enrolled in this study. Retinal vessel density was quantitatively measured by OCTA, including radial peripapillary capillary vessel density (RPC-VD), superficial and deep capillary plexus vessel density (SCP/DCP-VD). Structural parameters were collected from optical coherence tomography (OCT), including retinal thickness and subfoveal choroidal thickness (SFCT). Furthermore, LASSO-penalized logistic regression was used to construct the diagnostic model based on retinal parameters. ROC curves and nomogram plots were used to assess the diagnostic ability of this model for ICAS. ResultsThe macular SCP-VD of mild ICAS patients was significantly lower than that of controls and lower than that of nonmild ICAS patients (all p < 0.05). However, there was no difference among the three groups in terms of DCP-VD (p > 0.05). RPC-VD could effectively discriminate between the mild ICAS group and the nonmild ICAS group (p = 0.005). For structural OCT, only the SFCT decreased as the ICAS degree increased (p < 0.05). Diagnostic scores based on retinal parameters showed a strong diagnostic capability for mild ICAS (AUC = 0.8656). ConclusionMild ICAS patients exhibited distinct retinal features compared to nonmild ICAS patients and control subjects. OCTA potentially represents a promising method for the early detection of ICAS patients and the noninvasive surveillance of haemodynamic changes in those patients.

Changes of retinal structure and function in patients with internal carotid artery stenosis

BackgroundTo investigate the structural and functional changes of the retina in patients with different degrees of internal carotid artery (ICA) stenosis.MethodsThis cross-sectional study included patients with varying degrees ICA stenosis. Clinical characteristics of 41 patients were collected after being divided into four groups according to the ICA stenosis indicated by computed tomographic angiography (Group 0: without ICA stenosis, Group 1: ipsilateral slight ICA stenosis, Group 2: ipsilateral moderate ICA stenosis, Group 3: ipsilateral severe ICA stenosis). Retinal vessel caliber (RVC) was measured quantitatively with the Integrative Vessel Analysis software. The retinal sensitivity was examined with the MP-3 microperimeter. The relationships among central retinal artery equivalent (CRAE), central retinal vein equivalent, arteriole to venule ratio (AVR), mean retinal sensitivity (MS) and ICA stenosis degree were analysed.ResultsThe CRAE in Group 3 were significantly smaller compared with Group 0, Group 1 and Group 2 (P < 0.001, P < 0.001, P = 0.002). Significant decrease was found between Group 3 with other groups in MS at fovea (P < 0.001, P < 0.001, P = 0.002). Moreover, there was a positive correlation found between MS and CRAE (Beta = 0.60, P < 0.001 at fovea; Beta = 0.64, P < 0.001 at 2 degree; Beta = 0.60, P < 0.001 at 4 degree; Beta = 0.55, P < 0.001 at 8 degree; Beta = 0.53, P < 0.001 at 12 degree).ConclusionsThe present study revealed smaller CRAE and AVR in ipsilateral severe ICA stenosis patients. And the MS decreased in patients with severe ICA stenosis. In addition, MS had a positive correlation with CRAE.

The risk factors of old silent brain infarctions in carotid artery stenosis.

This study aims to investigate the risk factors of old ipsilateral silent brain infarctions (iSBIs) in patients with internal carotid artery (ICA) stenosis. Consecutive patients with unilateral ICA stenosis ≥ 50% or occlusion were retrospectively enrolled. Old iSBIs were assessed on magnetic resonance imaging. Baseline characteristics and imaging features were compared between patients with and without iSBIs. Multivariable regression analysis was conducted to identify independent risk factors of iSBIs. We enrolled 274 patients with unilateral ICA stenosis ≥ 50% or occlusion. One hundred thirty-three patients had iSBIs to stenosed ICA (48.54%). One hundred thirty-seven patients had recent brain infarction on either side (50.0%). The patients with iSBIs had a lower level of high-density lipoprotein [OR 0.60, 95% CI (0.36-0.96), P = 0.045], higher prevalence of irregular/ulcer plaque [OR 10.71, 95% CI (4.60-24.95), P < 0.0001], and incompleteness of circle of Willis [OR 0.27, 95% CI (0.16-0.45), P < 0.0001] in all enrolled patients. In the patients without recent infarction on either side, lower level of high-density lipoprotein [OR 0.42, 95% CI (0.27-0.88), P = 0.031], higher prevalence of irregular/ulcer plaque [OR 12.73, 95% CI (4.13-39.22), P < 0.0001] and incompleteness of circle of Willis [OR 0.24, 95% CI (0.11-0.50), P = 0.004] were independently associated with iSBIs. The results were similar in ICA stenosis patients with recent brain infarction on either side. In patients with carotid stenosis, incompleteness of circle of Willis, irregular/ulcer plaque, and lower level of high-density lipoprotein were independently associated with old iSBIs.

Psychological Determinants of Attitude to Surgery in Internal Carotid Artery Stenosis Patients.

The basic way to prevent cerebral stroke in symptomatic 70–99% stenosis of internal carotid artery (ICA) is an open or endovascular surgical procedure. Psychological research done so far among ICA stenosis patients focused on cognitive functioning changes. The objective was to assess attitude to surgery in relation to self-efficacy, life quality perception, and health locus of control in ICA stenosis patients. Materials and Methods: The study involved 53 asymptomatic ICA stenosis patients, aged from 53 to 81. Four scales were applied: Generalized Self-Efficacy Scale (GSES); Satisfaction With Life Scale (SWLS); Multidimensional Health Locus of Control Scale (MHLC); and a simple scale to examine the attitude to surgery, where “−10” stands for the maximally negative attitude, “0”—neutral, and “+10”—maximally positive. The obtained results were put to statistical analysis. Results: It was found that women and men assessed their attitude to the surgery as positive (M = 7.92; SD = 3.094), though the men estimated it slightly higher (M = 8.03; SD = 3.02) than the women (M = 7.67; SD = 3.37). The mean value of self-efficacy was high (M = 32.53; SD = 6.231), and slightly higher for the men (M = 32.79; SD = 5.576) compared to the women (M = 31.87; SD = 7.836). The patients generally tended to manifest the external personal health locus of control (M = 28.62; SD = 3.17). The runner-up was internal health locus of control (M = 26.02; SD = 3.775), and the next one—external impersonal aspect (chance/luck) (M = 23.57; SD = 4.457). The mean assessment of the patients’ own life quality proved to be above average (M = 23.60) but varied (SD = 5.95). The women perceived the quality of their lives as better (M = 24.33; SD = 6.422) than the men (M = 23.32; SD = 5.818). Very strong positive correlations were found between self-efficacy and life quality assessment (p < 0.001) and between the internal and external personal aspects of health locus of control (p < 0.007) in the women, and positive correlations were found between the attitude to surgery and internal health locus of control (p < 0.021) in the men. Conclusions: When breaking the news of a need to have a surgical intervention due to ICA stenosis, the physician should strongly refer to the value of human life and health. The message should arise from external (in the case of women) or internal (in the case of men) motivation to undergo surgery, and enhance the patient’s conviction that the disease should be considered a challenge which must be taken to reverse their unfavorable situation and improve life quality.

Abstract WMP41: The Value of Arterial Spin-Labeling Imaging in the Cerebral Collateral Circulation Evaluation of Carotid Occlusive Disease; Correlation Study With Acetazolamide-Stress Single Photon Emission Computed Tomography

Introduction: We investigated the relationship between the level of cerebral collateral circulation on arterial spin-labeling (ASL) magnetic resonance imaging (MRI) and cerebrovascular reserve (CVR) on acetazolamide (ACZ)-stress single photon emission computed tomography (SPECT) brain scans in internal carotid artery (ICA) stenosis. Methods: This study enrolled 129 patients with severe ICA stenosis (&gt;70%). Collateral circulation was assessed in pulsed ASL images based on the presence of arterial transit artifact (ATA) that late-arriving flow appears as serpiginous high ASL signal within cortical vessels. CVR based on rest-SPECT and ACZ-stress SPECT with Tc-99m-ECD was calculated. The ASL CBF maps were independently assessed by two neuroradiologists blinded to clinical information. The two neuroradiologists graded on two slices of ASL images corresponding to Alberta Stroke Program Early Computed Tomography Score (ASPECTS) location using a 4-point scale for ASL intensity. Results: With ACZ-stress SPECT, the 88/129 (68%) patients showed normal CVR and 41/129 (32%) patients showed decreased CVR. In 73/88 (82%) of the normal CVR group patients, ASL showed ATA in ipsilateral to the stenosis. In 19/41 (46%) of the decreased CVR group patients, ASL showed no evidence of ATA in ipsilateral to the stenosis. Significant positive relationship was observed between the normal CVR group and the ATA showing group in ICA stenosis patients (p = 0.001, chi-square test). The ASL-based ASPECTS scores of brain in the ipsilateral side was lower than the scores in the contralateral side to the ICA stenosis (p &lt; 0.0001, Wilcoxon signed rank test). The ASL-based ASPECTS scores of brain ipsilateral side to the ICA stenosis was lower in the reduced CVR group than normal CVR group (p = 0.005). Conclusion: This study demonstrated the statistically significant positive correlation between good collaterals on ASL MRI and intact CVR in patients with ICA stenosis.

Abstract WP474: Improvement of Cognitive Function and Reorganization of Brain Networks Following Carotid Endarterectomy and Carotid Artery Stenting

Background: Internal carotid artery stenosis (ICS) can lead to cognitive impairment as well as ischemic stroke. Although carotid revascularization surgery, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, the effect of revascularization on cognitive function is controversial. In this study, we examined the resting-state functional connectivity (FC) in ICS patients undergoing revascularization surgery, with a special focus on the Default Mode Network (DMN). Methods: We prospectively enrolled 24 ICS patients, who were expecting the intervention of CEA (14 cases) or CAS (10 cases). Cognitive assessment, including the Mini-Mental State Examination (MMSE), the Frontal Assessement Battery (FAB), and the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and rs-fMRI were administered ≤ 1 week preoperatively and postoperatively at 1 week. For the analysis of FC, a seed was placed in the region associated with DMN. Results: After revascularization surgery, significant improvement in the score of MMSE (27.4 vs 28.4, P = 0.03) and MoCA-J (23.1 vs 25.0, P = 0.0001) was found. As for the analysis of the CAS and CEA groups, the MoCA-J score of the CEA group (24.1 vs 26.1, P = 0.001) and the MMSE score of the CAS group (26.0 vs 28.4, P = 0.01) showed statistically significant improvements. In both CAS and CEA groups, Seed-to-Voxel focusing on DMN revealed increased connectivity between medial prefrontal cortex and precuneus. Conclusion: Both CEA and CAS are associated with an improvement in neurocognitive performance and reorganization of functional connectivity, including DMN.

Somatosensory Evoked Potential and Transcranial Doppler Monitoring to Guide Shunting in Carotid Endarterectomy.

Clamping of the internal carotid artery (ICA) during carotid endarterectomy (CEA) is a critical step. In our neurosurgical department, CEAs are performed with transcranial Doppler (TCD) and somatosensory evoked potential (SEP) monitoring with a 50% flow velocity/amplitude decrement warning criteria for shunting. The aim of our study was to evaluate our protocol with immediate neurologic deficits after surgery for the primary end point. This is a single-center retrospective cohort study of symptomatic and asymptomatic ICA stenosis patients from January 2012 to June 2015. Only those cases in which CEA was performed with both modalities (TCD and SEP) were included. The Mann-Whitney U test was applied to evaluate TCD and SEP ratios based on immediate postoperative neurologic deficits. A total of 144 patients were included, 120 (83.3%) with symptomatic ICA stenosis. The primary end point was met by six patients (4.2%); all of them were patients with a symptomatic ICA stenosis. The stroke and death rate was 1.4%. Ratios of SEP amplitudes demonstrated significant differences between patients with and without an immediate postoperative neurologic deficit at the time of ICA clamping (p = 0.005), ICA clamping at 10 minutes (p = 0.044), and ICA reperfusion (p = 0.005). Ratios of TCD flow velocity showed no significant difference at all critical steps. In this retrospective series of simultaneous TCD and SEP monitoring during CEA surgery of predominantly symptomatic ICA stenosis patients, the stroke and death rate was 1.4%. SEP seemed to be superior to TCD in predicting the need for an intraoperative shunt and for predicting temporary postoperative deficits. Further prospective studies are needed.

Predicting the Risk of Stroke in Chinese Internal Carotid Artery Stenosis Patients Underwent Carotid Artery Stenting: Validation and Improvement of Siena Carotid Artery Stenting Risk Score

Background: Siena carotid artery stenting (CAS) risk score is developed based on Chinese internal carotid artery (ICA) stenosis patients recruited in Italy, whether it is equally applicable in Chinese remains unknown. We aimed to investigate Siena CAS risk score value for predicting stroke risk in ICA stenosis patients underwent CAS and explore additional factors for improving accuracy of scoring system. Methods: Totally 401 patients with ICA stenosis who underwent CAS were enrolled. The clinical data (including patient characteristics, lesion features, and procedure-related features) were collected and the Siena CAS score was calculated. Stroke incidence with 30 days was documented. Results: The incidence of stroke was 4.5%, and the Siena CAS score in stroke patients was higher compared with nonstroke patients, further receiver operating characteristic (ROC) curve illustrated that Siena CAS score was acceptable at predicting stroke risk with area under curve (AUC) of .743 (95%CI: .638-.848). Multivariate logistic regression model revealed that Siena CAS score and current fasting-blood glucose (FBG) greater than 7.1 mmol/l independently predicted higher stroke risk; followed ROC curve disclosed that Siena CAS score combined with current FBG greater than 7.1 mmol/l was of good value in predicting stroke risk (AUC: .770 (95%CI: .677-.863)), which was numerically increased compared with Siena CAS score alone. Conclusions: Siena CAS risk scoring system exhibits to be a useful tool to predict stroke risk, and the combination of Siena CAS score and current increased FBG might be a more accurate stratification for stroke risk in Chinese ICA stenosis patients after CAS.

Abstract 138: Correlation of Cerebrovascular Reserve Assessed by Acetazolamide-stress SPECT With Collaterals on Arterial Spin-labeling MRI in Patients With Carotid Occlusive Disease

Purpose: We evaluated the correlation between cerebrovascular reserve (CVR) on acetazolamide (ACZ) -stress single photon emission computed tomography (SPECT) brain scans and collaterals on arterial spin-labeling (ASL) magnetic resonance imaging (MRI) in internal carotid artery (ICA) stenosis. Materials and Methods: 86 patients with ICA stenosis (&gt;70%) were enrolled in this study. Including pulsed ASL, MRI was acquired on a 3 tesla system. On ASL, late-arriving flow appears as serpiginous high ASL signal within cortical vessels, which has been termed arterial transit artifact (ATA). Images were interpreted for the presence of ATA. 82/86 ICA stenosis patients underwent SPECT imagings with Tc-99m-ECD in the resting and after ACZ challenge. We observed the presence of intracranial collaterals, which are manifested by ATA, on ASL brain perfusion scan. CVR based on rest-SPECT and ACZ-stress SPECT was calculated. With ACZ-stress SPECT, the 82 patients were grouped as either showing or not showing evidence of decreased CVR. We assessed the relationship between reduced CVR and intracranial collaterals shown as ATA on ASL brain perfusion. Results: In 61/86 (70%) of the ICA stenosis patients, ASL showed ATA in ipsilateral to the stenosis. With acetazolamide stress SPECT, the 27/82 (32%) patients showed evidence of decreased CVR. In 45/55 (81%) of the normal CVR group and 16/27 (59%) of the reduced CVR from the SPECT results, pulsed ASL showed ATA in ipsilateral to the stenosis. Significant positive relationship was observed between normal CVR group and ATA showing group in ICA stenosis patients on ASL brain perfusion (p=0.035, chi-square test). Conclusion: The ATA with ASL imaging as a noninvasive and no contrast demanding technique, can depict slow flow in excellent collateral vessels and has clinical utility in detecting CVR in patients with ICA stenosis.

Abstract TP569: The Evaluation of Cognitive Function Using Neural Network Analysis Before &amp; After Revascularization Surgery for Internal Carotid Artery Stenosis

Background: Internal carotid artery stenosis (ICS) can lead to cognitive impairment as well as ischemic stroke. Although carotid revascularization surgery, such as carotid endarterectomy (CEA) and carotid artery stenting (CAS), can prevent future strokes, the effect of revascularization on cognitive function is controversial. In recent years, the analysis of functional connectivity (FC) in resting-state functional MRI (rs-fMRI) has been used to investigate the effects of cognitive interventions. In this study, cognitive function is evaluated in ICS patients undergoing revascularization surgery with rs-fMRI. Methods: A prospective study was conducted among 17 ICS patients who were expecting revascularization surgery. Cognitive assessment, including the Mini-Mental State Examination (MMSE), the Frontal Assessement Battery (FAB), and the Japanese version of the Montreal Cognitive Assessment (MoCA-J) and rs-fMRI were administered ≤ 1 week preoperatively and postoperatively at 3 months. For the analysis of FC, a seed region was placed in the posterior cingulate cortex (PCC) associated with cognitive function. Results: After revascularization surgery, significant improvement in the score of MMSE (28.1 vs 29.1, P = 0.01) and MoCA-J (24.0 vs 26.7, P = 0.001) was found. No significant difference was found in the score of the FAB (16.2 vs 16.8, P = 0.09) between before and after surgery. According to the analysis of FC, ICS patients showed increase of connectivity between PCC and posterior cingulate gyrus, and between PCC and precuneus postoperatively at 3 months. Conclusion: Revascularization surgery for ICS improves cognitive function. The cognitive improvement may be partly attributed to the increase of connectivity between PCC and posterior cingulate gyrus/precuneus.

Subfoveal choroidal thickness and volume in severe internal carotid artery stenosis patients.

To demonstrate the differences of retinal and choroidal structure changes in internal carotid artery (ICA) patients of China by enhanced-depth imaging optical coherence tomography (EDI-OCT). A retrospective review was conducted of 46 patients with a diagnosis of ICA stenosis greater than 65% on only one side (the opposite ICA Stenosis had less than 40% stenosis) from June 2015 through June 2016. All of the patients were combined with amaurosis fugax, but without any abnormality with other ocular examination. Thickness and volume of choroid and retina were manually measured by EDI-OCT. Differences were compared between ICA stenosis eyes and fellow eyes. There were no significant differences in the retinal thickness, macular retinal nerve fiber layer (mRNFL) thickness, inner thickness, or outer retinal thickness between the ICA Stenosis group and the control group (P=0.834, 0.187, 0.552, and 0.903, respectively). The mean central choroidal thickness of the ICA Stenosis group was significantly lower than that of the control group (239.70±23.76 µm vs 257.46±22.13 µm, P<0.001). The percentage of ICA stenosis was significantly associated with the central choroidal thickness, central retinal thickness, foveal center choroidal volume, and foveal center retinal volume (r=0.854, 0.678, 0.729, and 0.785, respectively; P<0.001). There were no significant differences in the retinal and choroidal volume values in the 4 inner and 4 outer sectors between the two groups. The choroidal thickness in severe ICA stenosis eyes is lower than in fellow eyes. The choroidal thinning may occur before the retinal changes in patients with ocular ischemic syndrome. Evaluations of choroidal thickness may be useful to choose the optimal therapeutic schedule for ICA patients.

The Impact of Carotid Artery Stenting on Cerebral Perfusion, Functional Connectivity, and Cognition in Severe Asymptomatic Carotid Stenosis Patients.

Asymptomatic carotid artery stenosis can lead to not only stroke but also cognition impairment. Although it has been proven that carotid artery stenting (CAS) can reduce the risk of future strokes, the effect of CAS on cognition is conflicting. In recent years, pulsed arterial spin labeling (pASL) MRI and resting-state functional MRI (R-fMRI) have been employed in cognitive impairment studies. For the present study, cognition is evaluated in severe asymptomatic carotid artery stenosis patients undergoing CAS, and the mechanisms underlying the cognitive change are explored by pASL MRI and R-fMRI. We prospectively enrolled 24 asymptomatic, severe (≥70%), unilateral internal carotid artery stenosis patients, who were expecting the intervention of CAS. Cognition assessment (including the Montreal Cognitive Assessment Beijing Version, the Minimum Mental State Examination, the Digit Symbol Test, the Rey Auditory Verbal Learning Test, and the Verbal Memory Test) and an integrated MRI program (pASL MRI, and R-fMRI) were administered 7 days before and 3 months after CAS. 16 subjects completed the follow-up study. After stenting, significant improvement in the scores of the MMSE, the Verbal Memory test, and the delayed recall was found. No significant difference was found in the scores of the Montreal Cognitive Assessment Beijing Version, the Digit Symbol Test, and the immediate recall. After CAS treatment, asymptomatic carotid artery stenosis patients showed increased perfusion in the left frontal gyrus, increased amplitude of low-frequency fluctuation (ALFF) in the right precentral gyrus, and increased connectivity to the posterior cingulate cortex (PCC) in the right supra frontal gyrus. However, no significant correlations were found between these imaging changes and cognition assessments. Successful CAS can partly improve cognition in asymptomatic carotid artery stenosis patients. The cognition improvement may be partly attributed to the increased perfusion in the left frontal gyrus, increased ALFF in the right precentral gyrus, and increased connectivity to the PCC in the right supra frontal gyrus.

Relationship between haemodynamic impairment and collateral blood flow in carotid artery disease

Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial arterial spin labeling (ASL) imaging. Cerebral blood flow and cerebrovascular reactivity were assessed with ASL before and after acetazolamide. Cerebral haemodynamics were normal in asymptomatic ICA stenosis patients, as opposed to patients with ICA occlusion, in whom the haemodynamics in both hemispheres were compromised. Haemodynamic impairment in the affected brain region was always present in symptomatic patients. The degree of collateral blood flow was inversely correlated with haemodynamic impairment. Recruitment of secondary collaterals only occurred in symptomatic ICA occlusion patients. In conclusion, both CBF and cerebrovascular reactivity were found to be reduced in symptomatic patients with steno-occlusive ICA disease. The presence of collateral flow is associated with further haemodynamic impairment. Recruitment of secondary collaterals is associated with severe haemodynamic impairment.

Abstract TMP44: Contrast Enhanced Ultrasound Can Detect Small Disruption of Carotid Plaques Related to Symptomatic Internal Carotid Artery Stenosis

Background: The ulcerated atheroma of the carotid artery is a risk factor of ipsilateral ischemic stroke. Contrast-enhanced ultrasound (CEUS) is a novel noninvasive technique useful for evaluating the morphology of carotid plaques, and can detect small disruptions on plaque surface. However, it remains unclear whether the disrupted carotid plaque detected by CEUS is related to the symptomatic internal carotid artery stenosis (ICS). Methods: A total of 79 ICS patients who underwent carotid endarterectomy (CEA) were enrolled from July 2010 to July 2015. Before operation, ICA lesions were examined by color Doppler ultrasound (CDUS) and CEUS using perflubutane. The ulceration was diagnosed when both of the color Doppler signal on CDUS and the pooling of microbubbles on CEUS were observed within the plaque. The disruption was diagnosed only by CEUS when microbubbles pooled through the fissured surface, unlike the linear delineation of neovessels. We validated findings on ultrasound compared with the histopathological findings of ulceration and present/recent plaque rupture. The associations between ulceration/disruption on ultrasound and symptomatic ICS (with a history of ipsilateral transient ischemic attack and/or ischemic stroke) were investigated. Results: Of 79 subjects (mean age 71.2±6.8 years old, 78 men), 55 had symptomatic ICS. The ulceration by CEUS and CDUS was recognized in 20 patients (25%), and the disruption on plaque surface was seen by CEUS solitary in 26 patients (33%). The sensitivity and specificity of detecting plaque ulceration or disruption using CEUS compared with histopathological findings were 0.57 (45/66) and 1.00 (13/13), respectively. The detection rate of ulceration or disruption using CEUS was higher in symptomatic ICS than in asymptomatic ICS (66% vs 42%, P=0.049). Compared to plaques without ulceration/disruption on ultrasound, prevalence of symptomatic ICS was higher in plaques with the disruption (88% vs 58%, P=0.01), whereas it was similar in plaques with the ulceration (65% vs 58%, P=0.77) Conclusion: Small disruptions on carotid plaque surface detected by CEUS were significantly related to symptomatic ICS and this results may help the detailed assessment of plaque vulnerability.

Anterior temporal artery tap to identify systemic interference using short-separation NIRS measurements: A NIRS/EEG-tDCS study.

Transcranial direct current stimulation (tDCS) has been shown to modulate neural activity. Neural activity has been shown to be closely related, spatially and temporally, to cerebral blood flow (CBF) that supplies glucose via neurovascular coupling. Therefore, noninvasive and continuous monitoring of neural activity is possible with a measure of cerebral hemoglobin oxygenation using near-infrared spectroscopy (NIRS). In principal accordance, NIRS can capture the hemodynamic response to tDCS but the challenge remains in removing the systemic interference occurring in the superficial layers of the head that are also affected by tDCS. An approach may be to use short optode separations to measure systemic hemodynamic fluctuations occurring in the superficial layers which can then be used as regressors to remove the systemic contamination. Here, we demonstrate that temporal artery tap may be used to better identify systemic interference using this short-separation NIRS. Moreover, NIRS-EEG joint-imaging during anodal tDCS was used to measure changes in mean cerebral haemoglobin oxygen saturation (rSO2) along with changes in the log-transformed mean-power of EEG within 0.5 Hz-11.25 Hz. We found that percent change in the mean rSO2 better correlated with the corresponding percent change in log-transformed mean-power of EEG within 0.5 Hz-11.25 Hz frequency band after removing the systemic contamination using the temporal artery tap method. Based on our findings, we propose that anterior temporal artery tap technique presented in this paper may be able to classify carotid stenosis, external carotid artery stenosis, and internal carotid artery stenosis patients using the laterality in the hemodynamic response evoked by anodal tDCS both at the brain as well as at the superficial layers. These findings may have important implications for both prognosis and rehabilitation of patients with intracranial stenosis.

Abstract 168: Coated-Platelets Improve TIA/Stroke Prediction in Asymptomatic Internal Carotid Artery Stenosis

Background: Coated-platelets, a subset of procoagulant platelets observed upon dual agonist stimulation with collagen and thrombin, support a robust prothrombinase activity and provide a unique measure of platelet thrombotic potential. Coated-platelet levels are increased in large artery stroke compared to controls, and higher levels are associated with early stroke recurrence. We now examine whether coated-platelet levels predict TIA/stroke in asymptomatic internal carotid artery (ICA) stenosis. Methods: Consecutive patients referred for carotid Doppler evaluation were enrolled. Those taking anticoagulants, with dementia, or TIA/stroke within 6 months before enrollment were excluded. Coated-platelets were determined at baseline and reported as percent of cells converted to coated-platelets. Subjects were followed for up to 3 years for TIA/stroke. A receiver operating characteristic curve (ROC) analysis was conducted to compare performance of two models in predicting incident TIA/stroke. The first model included stenosis severity (&lt;70% or ≥70%) while the second model included stenosis severity (&lt;50% or ≥50%) and coated-platelet level as predictors. Results: We enrolled 343 patients. Follow-up ranged from 4 days to 39.7 months (mean 10.6 months). Fourteen TIA/strokes were observed. Ten were carotid-related. ROC analysis showed significant improvement in the predictive ability of the stenosis (≥50%) plus coated-platelets model compared to the stenosis (≥70%) only model (AUC: 0.88 ± 0.05 versus 0.71 ± 0.08, respectively; p=0.05). A cut-off of 46.5% for coated-platelet levels in combination with stenosis ≥50% yielded a sensitivity of 0.70 (0.42-0.98; 95% CI), specificity of 0.91 (0.88-0.94), positive predictive value of 0.18 (0.06-0.31), and a negative predictive value of 0.99 (0.98-1.0). Coated-platelet levels at 6 months did not significantly differ from baseline (p=0.69). Conclusions: Coated-platelet levels identify asymptomatic ICA stenosis patients at low risk for carotid-related stroke, which suggests a role for coated-platelets in risk stratification prior to revascularization.