Degree Of Internal Carotid Artery Stenosis Research Articles

Correlation between Ultrasound Peak Systolic Velocity and Angiography for Grading Internal Carotid Artery Stenosis.

(1) Background: The success of carotid revascularization depends on the accurate grading of carotid stenoses. Therefore, it is important for every vascular center to establish its protocols for the same. In this study, we aimed to determine the peak systolic velocity (PSV) thresholds that can predict moderate and severe internal carotid artery (ICA) stenoses. (2) Methods: To achieve this, we enrolled patients who underwent both duplex ultrasound (DUS) and invasive carotid artery digital subtraction angiography (DSA). The degree of ICA stenosis was assessed using the North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the European Carotid Surgery Trial (ECST) protocols. The PSV thresholds were determined using receiver operating characteristic (ROC) curves. (3) Results: Our study included 47 stenoses, and we found that the PSV cut-off for predicting ≥70% NASCET ICA stenoses was 200 cm/s (sensitivity 90.32%, specificity 93.75%). However, PSV did not correlate significantly with ≥50% NASCET ICA stenoses. On the other hand, the optimal PSV threshold for predicting ≥80% ECST ICA stenoses was 180 cm/s (sensitivity 100%, specificity 81.82%). (4) Conclusions: Based on our findings, we concluded that PSV is a good and simple marker for the identification of severe stenoses. We found that PSV values correlate significantly with severe NASCET and ECST stenoses, with 200 cm/s and 180 cm/s PSV thresholds. However, PSV was not reliable with moderate NASCET stenoses. In such cases, complementary imaging should be used.

Internal carotid artery stenosis: hemodynamics in the ipsilateral ACA affects CT angiography manifestations.

This study aimed to evaluate whether CT angiography (CTA) manifestations in anterior cerebral artery a1 segment (A1) were related to the hemodynamics in patients with internal carotid artery stenosis (ICAS). A total of 97 cases were selected. The degree of ICAS and symmetry of A1 were evaluated by CTA examination. Hemodynamic indexes were detected by transcranial Doppler (TCD). The differences in CTA presentations of A1 and hemodynamics between the vessels on the stenotic and contralateral sides were analyzed according to the different degrees of stenosis. The degree of ICAS according to the different manifestations of A1 and the hemodynamics of A1's adjacent vessels were also analyzed. In the case of unilateral ICAS, the difference in Vm of A1 between the stenotic and the contralateral side was the most significant relative to the stenosis degree. When unilateral ICAS was ≥70%, the presentation of A1 on the stenotic side was more slender or non-visualized compared to that on the contralateral side, while in cases with unilateral stenosis <70% or bilateral stenosis with a similar degree of stenosis, A1 were mainly symmetrical. When A1 on the side of ICAS was slender or non-visualized, the Vm of A1 was significantly slower than that on the contralateral side (P < 0.001). The CTA manifestations of A1 on the side of ICAS embodied the overall changes of the intracranial hemodynamics after ICAS. A combination of TCD and CTA examination of A1 can assist in judging the location and degree of ICAS.

Is External Carotid Artery Hemodynamics Helpful in Detecting Internal Carotid Artery Stenosis?

Introduction: There is a paucity of validated external carotid artery (ECA) velocity criteria and data on the association between ECA velocities and internal carotid artery (ICA) stenosis by carotid duplex ultrasound (CDU) scanning. Our objectives were to determine the relationships between ECA peak systolic velocity (PSV) and percent stenosis seen on confirmatory imaging, as well as to correlate ECA hemodynamics with known ICA disease by CDU. Methods: A retrospective chart review was performed for patients who had CDU, as well as confirmatory testing such as angiography, at a single academic medical center. ICA stenosis was grouped into 4 categories (0 = &lt;50%, 1 = 50%-69%, 2 = 70%-99%, 3 = 100%) based on validated CDU criteria. ECA PSVs were analyzed, in addition to degree of both ECA and ICA stenosis from the same CDU study. Results: Of 247 carotid arteries reviewed, 136 vessels were included in the final analysis. The mean PSV of the normal ECA cohort (&lt;50% ECA stenosis per the NASCET measurement method) was 135.3 ± 82.1 cm/s, and the mean PSV of the diseased ECA cohort was 279.7 ± 112.2 cm/s. Mean ECA PSV for each category of ICA stenosis was: ICA category 0 = 119.9 cm/s; category 1 = 200.4 cm/s; category 2 = 167.7 cm/s; and category 3 = 155.5 cm/s. There was a statistically significant but non-linear difference in ECA velocities between ICA stenosis categories 0 vs 1 (mean rank diff. −49.91 cm/s; P = .0007); and 0 vs 2 (mean rank diff. −32.61 cm/s; P = .0047). Conclusion: We have demonstrated a possible separation of &lt;50% vs ≥50% stenosis of the ICA using ECA PSV. Although the data suggest a weak but statistically significant correlation between ECA PSV and degree of ICA stenosis, further data with a larger sample size and confirmatory studies are needed to utilize ECA hemodynamics to indicate ICA disease.

Poststenotic Distal Caliber Reduction Predicts Very High-Grade Proximal Internal Carotid Artery Stenosis.

Angiography relates the residual lumen to the poststenotic distal lumen (NASCET criterion) and expresses the result in percent lumen reduction. This method is not applicable when there is a collapse of the distal lumen, as seen in severe stenosis. The purpose of this study was to evaluate whether the reduced poststenotic caliber could be an additional sonographic criterion for estimation of the degree of stenosis. We measured the caliber of the distal lumen of the extracranial internal carotid artery (ICA) in 57 patients with low-grade stenosis <50% (NASCET criterion), and in 57 patients with unilateral stenosis of ≥ 50 %. All were classified following international recommendations. The criteria used included the poststenotic velocity to discriminate moderate to high-grade stenosis (50-70%) from very high-grade (≥ 80 %) stenosis. In addition, we measured the interrater reliability of the ultrasonic measurement of the lumen in the distal ICA. In the group of patients with 50% to 70% stenosis, the distal lumen was 4.3 ± 0.6 mm. In the group with very high-grade stenosis ≥ 80%, the distal lumen was 2.6±0.5mm (p<0.0001). A distal lumen of 3.2 mm or less predicted a very high-grade stenosis with a sensitivity of 0.92 and a specificity of 0.96 (AUC 0.986; 95% CI 0.97-1.00; p=0.0001). The distal poststenotic lumen is an additional ultrasonic criterion to discriminate a very high-grade ICA stenosis from a lesser degree of ICA stenosis. It can help avoid misinterpretation due to the high variability of intrastenotic peak systolic velocities (PSV) in very high-grade ICA stenoses.

A preliminary study of relationship among the degree of internal carotid artery stenosis, wall shear stress on MR angiography and 18F-FDG uptake on PET/CT

BackgroundThis preliminary study was undertaken to evaluate relationship among the degree of internal carotid artery (ICA) stenosis, wall shear stress (WSS) by computational fluid dynamics (CFD) on magnetic resonance angiography (MRA) and 18F-FDG uptake of ICA on PET/CT. MethodsA total of 40 carotid arteries in 20 patients with carotid atherosclerotic disease were examined with MRA and 18F-FDG PET/CT. Atherosclerotic risk factors were assessed in all patients. Degree of ICA stenosis was calculated according to NASCET method. CFD analysis was performed and maximum WSS (WSSmax) was measured. 18F-FDG uptake in ICA was quantified using maximum target-to-blood pool ratio (TBRmax). ResultsAtherosclerotic risk factors did not affect imaging findings. There were significant correlations between WSSmax and degree of ICA stenosis (ρ = .81, P < .001), WSSmax and TBRmax (ρ = .64, P < .001), and TBRmax and degree of ICA stenosis (ρ = .50, P = .001). ConclusionsThese preliminary results indicate that there may be significant correlations among the degree of ICA stenosis, WSSmax and TBRmax in patients with carotid artery stenosis.

Carotid Duplex Poorly Predicts Stroke Risk During Transcatheter Aortic Valve Replacement

Patients undergoing surgical aortic valve replacement, in isolation or with concomitant coronary artery bypass grafting, have historically been screened for carotid artery disease prior to surgery. Over the past decade, transcatheter aortic valve replacement (TAVR) has incrementally become the predominant technique for the treatment of severe aortic stenosis. The relationship between internal carotid artery stenosis (ICAS) and risk of periprocedural stroke in the TAVR population is uncertain. We sought to evaluate our institution's outcomes with the TAVR procedure and the association with preoperative carotid duplex scan (CDS) results. A retrospective review of a single institution TAVR registry over a 5-year period was performed. All patients with pre-operative carotid imaging were included. Outcomes included in-hospital, 30-day, and 1-year stroke and all-cause mortality rates. The diagnosis of post-operative stroke was based on neurological exam and confirmed by radiologic imaging. Standard statistical analysis was performed. A total of 436 patients met inclusion criteria. The prevalence of ICAS >50% was 18.3% and 70-99% stenosis was 4.8%. The in-hospital stroke and mortality rates were 2.3% and 1.2%, respectively. The cumulative 30-day and 1- year stroke rates were 3.7% and 6%, respectively. All were ischemic in nature. Bilateral infarcts were identified in 46.2% of stroke patients and 11.5% had an ipsilateral ICAS >50%. A large majority of stroke patients (23, 88.5%) had an ipsilateral ICAS of <50%. Less than 0.5% of patients had ICAS >70% and subsequently had an ipsilateral stroke within 30 days of procedure. The preoperative CDS identified carotid lesions that met criteria for elective repair in only 4.8% of patients. Of these, 9.5% suffered a stroke in the first 30 days after surgery. Over 90% of patients who had a stroke had less than 70% stenosis present in either carotid artery and there was no correlation between degree of ICAS and risk of stroke during the follow-up period. Routine CDS prior to TAVR does not predict in-hospital or 30-day stroke. As TAVR programs evolve, expand, and proliferate across the country, routine preoperative CDS is unlikely to determine the need for pre-operative carotid revascularization or predict stroke risk.

FLAIR Vascular Hyperintensities Indicate Slow Poststenotic Blood Flow in ICA Stenosis.

Occlusion or significant stenosis of the internal carotid artery (ICA) in the cervical segment is commonly associated with apoststenotic decrease in the downstream blood flow and perfusion. Fluid attenuated inversion recovery (FLAIR) vascular hyperintensities (FVH) are aphenomenon that represents slow arterial blood flow. In this study, we investigated the frequency and extent of FVH in the distal ICA in patients with proximal ICA stenosis. We analyzed the magnetic resonance imaging (MRI) findings in 51patients with atotal of 60cervical ICA stenoses with special focus on the frequency and extent of FVH in the area of the petrous segment of the ICA on FLAIR images and correlated these with Doppler/duplex sonography results. In 46(76.7%) patients with ICA stenosis, FVH could be detected in the petrous segment of the ICA: in 19(41.3%) patients athin hyperintense rim near the vessel wall (grade1), in 24(52.2%) patients astrong hyperintense rim near the vessel wall (grade2), and in 3(6.5%) patients ahyperintense filling of the entire lumen (grade3) was observed. The extent of FVH in the ICA in the petrous segment showed a high negative correlation with the poststenotic flow velocity (Spearman correlation, R = -0.75, p < 0.001), and moderate correlation with the degree of ICA stenosis (Spearman correlation, R = 0.51, p< 0.001). An FVH in the petrous ICA is commonly seen among patients with steno-occlusive disease in proximal ICA and could therefore be useful to recognize aproximal ICA stenosis even on FLAIR images.

Analysis of Differentiated Approach Effectiveness in Patients with Varying Degrees of Severity of Chronic Ocular Ischemic Syndrome Caused by Internal Carotid Artery Stenosis

Purpose: to study the effect of differentiated treatment approach in patients with varying degrees of severity chronic ocular ischemic syndrome (OIS) on clinical course of disease and hemodynamics of eyes in prospective research.Patients and methods. The research included 20 patients with chronic OIS. Patients were divided into 4 groups due to severity of chronic OIS and type of treatment. 1st group — 7 patients with moderate severity chronic OIS and hemodynamically significant of internal carotid artery stenosis (ICAS); only carotid endarterectomy (CE) of ICAS was performed. 2nd group — 6 patients with severe degree chronic OIS and hemodynamically significant stenosis of ICAS; 2 weeks before CE, panretinal photocoagulation (PRP) of retinal capillary non-perfusion areas was performed. 3rd group — 4 patients with severe degree chronic OIS, complicated by rubeosis iris and increased IOP on hypotensive regimen, on the background of hemodynamically insignificant ICAS; PRP of retina was performed. 4th group — 3 patients with moderate severity chronic OIS with hemodynamically insignificant ICAS; course of neuroprotective therapy was performed. All patients underwent standard and specialized ophthalmologic examination methods. Assessment of blood flow in brachiocephalic vessels, eye vessels was performed by ultrasound scan, spiral computed tomography, OCT-angiography with the AngioVue.Results. Monitoring of patients’ groups for 1 year after chronic OIS treatment allowed us to determine tactics of patient management depending on degree of ICAS and severity of chronic OIS. Reconstructive surgery at hemodynamically significant ICAS caused positive dynamic in intraocular blood flow, which contributed to improvement and preservation of BCVA in 71 % of patients. Preventive PRP of retina, before performing reconstructive surgery of ICAS, optimized and reduced the time of visual recovery. PRP of retina as independent method of treatment of chronic OIS, complicated by neovascular glaucoma, caused full or partial regression of neovascularization in iris, which increased possibilities of its effective treatment. Neuroprotective pharmacotherapy in early stages of chronic OIS, in absence of indications for reconstructive surgery and PRP of retina, improved the prognosis for patients’ vision.Conclusion. Differentiated treatment approach in patients with chronic OIS, due to changes of hemodynamics of internal carotid artery, has improved indexes of hemodynamic and visual acuity.

Association between Enlarged Perivascular Spaces and Internal Carotid Artery Stenosis: A Study in Patients Diagnosed by Digital Subtraction Angiography

Objective: An enlarged perivascular space (EPVS) is an imaging marker of cerebral small vessel disease, and its relationship with large artery disease is elusive. We investigated the EPVS in patients with internal carotid artery stenosis (ICAS) with the use of digital subtraction angiography (DSA) and tested the relationship between the degree of EPVS and the degree of ICAS; as well as the relationship between the degree of EPVS and white matter hyperintensity (WMH). Method: A total of 202 patients with or without ICAS diagnosed by DSA were enrolled. The maximal ICAS rates, the degrees of EPVS and WMH were measured. The patients’ clinical characteristics and laboratory parameters were recorded. Univariable analysis and multivariable regression were used to test their correlations. In a unilateral stenosis subgroup, the EPVSs in the ipsilateral hemisphere of stenosis and in the contralateral hemisphere were compared. Results: According to univariable analysis, there were significant differences in age (P = .000), Hg1bc (P = .035) and folic acid (P = .008) among the subgroups based on the degrees of EPVS in the basal ganglia (BG). Age (P = .000) and the level of fibrinogen (P = .018) differed statistically among the subgroups based on the degrees of EPVS in the white matter (WM). The correlation between the degrees of WM-EPVS and the ICAS levels was tested with a gamma test: G = .280, P = .001. The ordinal multivariable regression model showed that age was independently associated with both BG-EPVSs and WM-EPVSs. A current smoker status was also independently associated with WM-EPVSs. ICAS level was associated with the severity of WM-EPVSs after adjusting for other risk factors. The degree of BG-EPVS was not correlated with the degree of stenosis. (P = .101). In 59 patients with unilateral ICAS, as tested by the Wilcoxon signed ranks test, the WM-EPVS scores in the ipsilateral hemisphere of stenosis were higher than those in the contralateral hemisphere. (P = .004), but there was no difference in BG-EPVSs (P = .070). Both BG-EPVSs and WM-EPVSs were independently correlated with WMH. Conclusions: BG-EPVSs and WM-EPVSs have different risk factors. WM-EPVSs but not BG-EPVSs are correlated with ICAS.

Do Common Carotid Artery Velocities Consistently Decrease With Proximity to the Bifurcation?

Distal (near bifurcation) common carotid artery (CCA) peak systolic velocity (PSV) values are lower than near the origin (proximal). We investigate whether this applies to patients with internal carotid artery (ICA) stenosis ≥ 50% (PSV ≥ 125 cm/s). We studied 328 patients. We excluded carotid arteries with CCA stenosis and carotid endarterectomy. We evaluated degree of stenosis as absent, mild (1%-15%), moderate (16%-49%), and significant (≥50%; PSV ≥ 125 cm/s). We used paired t tests to compare the proximal with distal PSV values as a function of stenosis severity and analysis of variance for between stenosis differences. We studied 640 out of 656 bifurcations. Mean age was 68.9 (SD = 11.8) years, and 70% (228) men. Mean distal CCA PSV was 80.3 cm/s (SD = 23.1 cm/s) and proximal, 93.7 cm/s (SD = 26.6 cm/s). The difference between proximal and distal CCA PSV for ICA lesions &lt; 50% (n = 553; 14.8 ± 22.6 cm/s) was higher ( P = .004) than with an ICA stenosis ≥ 50% (n = 87; 4.6 ± 24.1 cm/s). While distal CCA PSV decreases in patients with absent/mild/moderate plaque, PSV velocities are more consistent along the length of the CCA with higher degrees of ICA stenosis. This might in part explain the reliability of the ICA/CCA velocity ratio for grading stenosis severity ≥50%.

Are Cerebral White Matter Lesions Related to the Presence of Bilateral Internal Carotid Artery Stenosis or to the Length of Stenosis Among Patients With Ischemic Cerebrovascular Events?

Background and purpose: Previous studies delivered contradicting results regarding the relation between the presence of an internal carotid artery stenosis (ICAS) and the occurence of white matter lesions (WMLs). We hypothesize that special characteristics related to the ICAS might be related to the WMLs. We examined the relation between the presence of bilateral ICAS, the degree and length of stenosis and ipsi-, contralateral as well as mean white matter lesion load (MWMLL).Methods: In a retrospective cohort, patients with ischemic stroke or transient ischemic attack (TIA) as well as ipsi- and/or contralateral ICAS were identified. The length and degree of ICAS, as well as plaque morphology (hypoechoic, mixed or echogenic), were assessed on ultrasound scans and, if available, the length was also measured on magnetic resonance angiography (MRA) scans, and/or digital subtraction angiography (DSA). The WMLs were assessed in 4 areas separately, (periventricular and deep WMLs on each hemispherer), using the Fazekas scale. The MWMLL was calculated as the mean of these four values.Results: 136 patients with 177 ICAS were identified. A significant correlation between age and MWMLL was observed (Spearman correlation coefficient, ρ = 0.41, p < 0.001). Before adjusting for other risk factors, a significantly positive relation was found between the presence of bilateral ICAS and MWMLL (p = 0.039). The length but not the degree of ICAS showed a very slight trend toward association with ipsilateral WMLs and with MWMLL. In an age-adjusted multivariate logistic regression with MWMLL ≥2 as the outcome measure, atrial fibrillation (OR 3.54, 95% CI 1.12–11.18, p = 0.03), female sex (OR 3.11, 95% CI 1.19–8.11, p = 0.02) and diabetes mellitus (OR 2.76, 95% CI 1.16–6.53, p = 0.02) were significantly related to WMLs, whereas the presence of bilateral stenosis showed a trend toward significance (OR 2.25, 95% CI 0.93–5.45, p = 0.074). No relation was found between plaque morphology and MWMLL, periventricular, or deep WMLs.Conclusion: We have shown a slight correlation between the length of stenosis and the presence of WMLs which might be due to microembolisation originating from the carotid plaque. However, the presence of bilateral ICAS seems also to be related to WMLs which may point to common underlying vascular risk factors contributing to the occurrence of WML.

Stenosis Length and Degree Interact With the Risk of Cerebrovascular Events Related to Internal Carotid Artery Stenosis.

Background and Purpose: Internal carotid artery stenosis (ICAS)≥70% is a leading cause of ischemic cerebrovascular events (ICVEs). However, a considerable percentage of stroke survivors with symptomatic ICAS (sICAS) have <70% stenosis with a vulnerable plaque. Whether the length of ICAS is associated with high risk of ICVEs is poorly investigated. Our main aim was to investigate the relation between the length of ICAS and the development of ICVEs.Methods: In a retrospective cross-sectional study, we identified 95 arteries with sICAS and another 64 with asymptomatic internal carotid artery stenosis (aICAS) among 121 patients with ICVEs. The degree and length of ICAS as well as plaque echolucency were assessed on ultrasound scans.Results: A statistically significant inverse correlation between the ultrasound-measured length and degree of ICAS was detected for sICAS≥70% (Spearman correlation coefficient ρ = –0.57, p < 0.001, n = 51) but neither for sICAS<70% (ρ = 0.15, p = 0.45, n = 27) nor for aICAS (ρ = 0.07, p = 0.64, n = 54). The median (IQR) length for sICAS<70% and ≥70% was 17 (15–20) and 15 (12–19) mm (p = 0.06), respectively, while that for sICAS<90% and sICAS 90% was 18 (15–21) and 13 (10–16) mm, respectively (p < 0.001). Among patients with ICAS <70%, a cut-off length of ≥16 mm was found for sICAS rather than aICAS with a sensitivity and specificity of 74.1% and 51.1%, respectively. Irrespective of the stenotic degree, plaques of the sICAS compared to aICAS were significantly more often echolucent (43.2 vs. 24.6%, p = 0.02).Conclusion: We found a statistically insignificant tendency for the ultrasound-measured length of sICAS<70% to be longer than that of sICAS≥70%. Moreover, the ultrasound-measured length of sICAS<90% was significantly longer than that of sICAS 90%. Among patients with sICAS≥70%, the degree and length of stenosis were inversely correlated. Larger studies are needed before a clinical implication can be drawn from these results.

Indications and Outcome of Carotid Doppler Ultrasound An Ophthalmic Perspective.

The purpose of this study was to assess indications and outcome of carotid Doppler ultrasound requested by ophthalmologists from an eye hospital over a period of three years. This retrospective study was designed to analyse data for all patients referred to have carotid Doppler ultrasound from 1999 to 2001. Colour fundus photograph was used to ascertain diagnosis of ocular condition. Detailed case note analysis was done to correlate patient details, indication, results of carotid Doppler, and status of anti-platelet treatment as well as presence of other risk factors. 107 patients were included in the study. 46.7% had normal internal carotid on Doppler while 53.3% patients had stenosis, 22.8% of which were significant. 15 out of 24 patients with retinal artery occlusion had internal carotid artery (ICA) stenosis. 2 out of 6 patients with migraine had significant stenosis. 12 patients had retinal vein occlusion (5 were bilateral), 9 of whom showed ICA stenosis. 14 of 15 patients with retinal emboli had stenosis of ICA. Other diagnoses included anterior ischaemic optic neuropathy, cranial nerve palsy, etc. 42 patients had 1 to 3 risk factors, and 11 patients had more than 3 risk factors. Ophthalmologists started anti-platelet management in 24 patients (42.1%) with some degree of ICA stenosis. Approximately 55% of our patients referred for carotid Doppler were positive for ICA stenosis with nearly a fifth of such referrals having more than 70% stenosis, which is considered to be clinically significant. Our results highlight the importance of such referrals for carotid Doppler for various ophthalmic conditions by the ophthalmologists. (Eur J Ophthalmol 2004; 14: 240-4).

Ultrasonographical Features Associated with Progression of Atherosclerosis in Patients with Moderate Internal Carotid Artery Stenosis.

Carotid artery stenosis (CAS) is a leading cause of ischemic stroke. Plaque stabilization is a major management approach. Information about the ultrasonographical and clinical features associated with the progression of moderate internal carotid artery (ICA) stenosis (50-69%) could assist with prognostication and risk factor modifications. We evaluated 287 patients with moderate ICA stenosis (50-69%) and subsequently evaluated them at follow-up points at 12, 24, and 36months. Patients were divided into three groups according to the degree of ICA stenosis: progression (70-99%, n = 48), stable (50-69%, n = 210), and regression (< 50%, n = 29). Responsible plaque thickness (RPT) across groups during follow-up was compared using a repeated measure ANOVA test. An ordinal regression was subsequently applied to identify risk factors for atherosclerosis progression. Male (P = 0.04), hypoechoic plaque (P < 0.01), smoking (P = 0.02), plaque ulceration (P = 0.05), and contralateral severe CAS or occlusions (P = 0.04) on ultrasound was more frequent in the progression group vs. other two groups. The ordinal regression revealed that only hypoechoic plaque (OR, 7.03; 95% CI, 3.34-14.81; P < 0.01) and contralateral ICA severe stenosis or occlusion (OR, 2.86; 95% CI, 1.41-5.80; P < 0.01) were independently associated with stenosis progression, while statin use was inversely associated with stenosis progression (OR, 0.26; 95% CI, 0.13-0.54; P < 0.01). Of note, symptomatic vs. asymptomatic moderate CAS at baseline was not associated with progression. For patients with moderate CAS, hypoechoic plaque, contralateral severe stenosis or occlusion on ultrasonography, and statin use are independently related to stenosis progression. Statin use may delay the progression of carotid stenosis.

Abstract WP139: The Correlation Between Supraorbital Artery Flow Patterns and Degree of Carotid Artery Stenosis

Objective: Patients with internal carotid artery (ICA) occlusion or severe stenosis usually have collateral via ophthalmic artery (OA). However, the relationship of blood flow patterns of OA and the degree of ICA stenosis has been rarely reported. Transcranial Doppler (TCD) is a promising modality to assess OA collateral when ICA lesion. Considered OA characteristics including tortuosity and anatomical variations, we try to evaluate the supraorbital artery (SA), the one of OA terminal branches, to analyze the relationship of flow with the degree of ICA stenosis. Materials and Methods: From Jun 2012 to Jan 2015, TCD were performed to 40 patients with ICA stenosis before and after carotid artery stenting (CAS). SA blood flow patterns were compared with the degree of ICA stenosis confirmed by conventional angiography. Results: 40 patients (29 men) were enrolled (mean age 64.9 yrs). Before CAS, the retrograde blood of SA was found in 40 patients. After stenting, the flow pattern reversed in 29 patients of these patients (29/40, 72.5%). The blood flow of SA was gradually reverse over time from angioplasty with balloon to several days after CAS. The patterns of these changes were categorized into four types: (A), flow spectrum completely reversed; (B), reverse flow spectrum associated with systolic notch; (C), flow spectrum forward at systolic and reverse at diastolic; (D), type flow spectrum entirely forward. Before balloon angioplasty (mean stenosis, 93.4%), A type was found in 39 of them, B type in 1 patient; after balloon dilatation (mean stenosis, 82.9%), 26 A types and 4 B, 5 C, 5 D types. Stent (mean stenosis, 14.9%), 1 A type, 4 B and 4 C, 29 D types. Conclusion: The flood flow patterns of SA may be associated with the degree of carotid stenosis evaluated with TCD and the blood flow may be reverse after CAS. This work was supported by the National Natural Science Foundation of China (Contractgrant number: 81471390 to N.M).

Leptomeningeal Collaterals Strongly Correlate with Reduced Cerebrovascular Reactivity Measured by Acetazolamide-challenged Single-photon Emission Computed Tomography Using a Stereotactic Extraction Estimation Analysis in Patients with Unilateral Internal Carotid Artery Stenosis.

Objective To assess the correlation between the angiographic appearance of cerebral collateral pathways or the degree of internal carotid artery stenosis (ICAS) and reduced cerebrovascular reactivity (CVR) estimated by single-photon emission computed tomography (SPECT) image analysis in patients with unilateral ICAS. Methods A retrospective analysis was performed in 42 patients with unilateral ICAS who underwent cerebral angiography and acetazolamide-challenged SPECT of the brain. Cerebral blood flow quantitation was performed using the quantitative SPECT/dual-table autoradiography method. The CVR in the middle cerebral artery (MCA) territory was evaluated using the stereotactic extraction estimation based on the Japanese extracranial-intracranial bypass trial (SEE-JET) program and classified as reduced (<18.4%) or non-reduced (≥18.4%). Angiographic collateralization was classified as circle of Willis (type 1), extracranial-intracranial (type 2), and leptomeningeal (type 3). The degree of ICAS was defined as severe (≥70% stenosis) or non-severe (<70%). Results Eight patients showed reduced CVR, including 6 (46%) of 13 with type 3 collaterals and 2 (7%) of 29 without type 3 collaterals (p=0.006). In contrast, type 1 and type 2 collaterals and severe ICAS were not significantly associated with reduced CVR. Conclusion In patients with unilateral ICAS, leptomeningeal collaterals are strongly correlated with reduced CVR in the MCA territory, which presumably increases the risk of cerebral hyperperfusion after carotid artery stenting (CAS). Therefore, these findings may be clinically applicable to the perioperative management of CAS.

COMPUTED ANGIOGRAPHY IN DEDICATED ASSESSMENT OF OCCLUSIVE CAROTID DISEASE FOR RECONSTRUCTIVE SURGERY PLANNING

Objective – to optimize dedicated assessment of carotid arteries in case of occlusive disease with computed angiography (CTA). Material and methods. During 2015–2016 years 65 patients underwent ultrasound examination and computed tomography examined before carotid surgery. Results. Aortic arc branching variants were observed in 26% cases. In 51% combined steno-occlusive process in common, internal carotid arteries and subclavian arteries was confirmed. In 29% of cases atherosclerotic plagues were detected in upper parts of common carotid arteries and such data changed surgical strategy. Patients included in study has internal carotid artery (ICA) stenosis more than 50% NASCET. Detailed assessment was used for cervical ICA distal to stenosis. In 62% of patients with carotid subocclusion narrowing in upper segments were detected. In 3 cases ascending pharyngeal artery arose from affected carotid artery and these findings change surgical approach. All patients underwent carotid surgery. Degree of ICA stenosis detected with CTA was conformed. CTA data for carotid plague extension were less informative – intraoperative plague length exceeded CTA results. Conclusion. CTA is high informative study that allows detailed assessment of occlusive carotid disease for carotid surgery.

Optimal Peak Systolic Velocity Thresholds for Predicting Internal Carotid Artery Stenosis Greater than or Equal to 50%, 60%, 70%, and 80%

We aimed to determine the optimal peak systolic velocity (PSV) thresholds for predicting ≥50%, ≥60%, ≥70%, and ≥80% internal carotid artery (ICA) stenosis. Patients who underwent both carotid ultrasonography and cerebral angiography during hospitalization were consecutively and retrospectively enrolled. The degree of ICA stenosis was calculated using the North American Symptomatic Carotid Endarterectomy Trial method on cerebral angiography. The optimal PSV thresholds for predicting ≥50%, ≥60%, ≥70%, and ≥80% ICA stenosis were determined using receiver operating characteristic curves and the Youden index. A total of 127 ICAs were analyzed. The optimal PSV thresholds for predicting ≥50%, ≥60%, ≥70%, and ≥80% ICA stenosis were 130 cm/s (sensitivity, 95%; specificity, 85%; positive predictive value [PPV], 75%; negative predictive value [NPV], 97%; overall accuracy, 88%), 160 cm/s (sensitivity, 91%; specificity, 94%; PPV, 83%; NPV, 97%; overall accuracy, 93%), 200 cm/s (sensitivity, 96%; specificity, 95%; PPV, 83%; NPV, 99%; overall accuracy, 95%), and 270 cm/s (sensitivity, 89%; specificity, 94%; PPV, 74%; NPV, 98%; overall accuracy, 94%), respectively. The optimal PSV thresholds for predicting ≥50%, ≥60%, ≥70%, and ≥80% ICA stenosis were 130 cm/s, 160 cm/s, 200 cm/s, and 270 cm/s, respectively. All of them had high diagnostic accuracies.

Correlation study of MRI intracranial hyperintense vessel sign and internal carotid artery stenosis

Objective To evaluate the correlation between intracranial hyperintense vessel sign (HVS) on fluid-attenuated inversion recovery(FLAIR) and the degree of the stenosis of internal carotid artery (ICA).The effect of carotid endarterectomy(CEA) on HVS was assessed.Methods A retrospective analysis of MR FLAIR sequence and cerebral-cervical computed tomography angiography(CTA) was performed in 1 total of 491 patients.Of the 491 patients,41 treated with CEA were evaluated using their pre-and post-operative image data.Patients were divided into ICA stenosis group and non-stenosis group according to the CTA imaging findings.The ICA stenosis group was subdivided into unilateral group and bilateral stenosis group.Furthermore,we measured and graded the ICA of the unilateral stenosis group into seven stenotic degrees,they were＜50％(n=40),50％-＜60％(n=15),60％-＜70％(n=17),70％-＜80％ (n=6),80％-＜90％ (n=7),90％-＜100％ (n=23),100％ (n=24),respectively.Chi square test was used to analyze the occurrence rates of HVS between ICA stenosis and non-stenosis group,and between ICA unilateral and bilateral stenosis group,respectively.Spearman rank correlation was performed to evaluate the correlation between the presence of HVS and stenotic degrees of the ICA.For the 41 patients who underwent CEA,pre-and post-operative image data were compared,focusing on the presence or disappearance of the HVS on MR FLAIR imaging.Results HVS on FLAIR images were observed in 81 of 177 patients(45.76％) with ICA stenosis,and in 59 of 314 patients(18.79％) without ICA stenosis.The occurrence rate of HVS was significantly higher in patients with ICA stenosis than those without ICA stenosis (x2=40.40,P＜0.01).There was no statistical significance in the occurrence rates of HVS between ICA unilateral stenosis group and bilateral stenosis group(x2=0.24,P＞0.05).The occurrence rates of HVS of ICA graded as the seven stenotic degrees were 22.00％(8/40),26.67％(4/15),35.29％(6/17),33.33％ (2/6),42.86％ (3/7),69.57％ (16/23),83.33％ (20/24),respectively.There was a significant positive correlation between the occurrence rates of HVS and the degrees of ICA stenosis(r=0.964,P＜0.01).HVS disappeared in 19(86.36％) out of 22 patients with HVS on pre-operative MR images after CEA in The remaining HVS in 3(13.64％) patients was attributed to the failure of completely recanalization of ICA.Conclusions A close relationship exists between HVS and ICA stenosis.The presence of HVS indicates a high probability of the existence of severe ICA stenosis.A further assessment for ICA stenosis is warranted.HVS disappearance after successful CEA indicates that HVS can be a useful marker for the the evaluation of consequence associated with CEA. Key words: Carotid stenosis; Magnetic resonance imaging

Functional MRI Study of Working Memory Impairment in Patients with Symptomatic Carotid Artery Disease

The neuropsychological tests in patients with internal carotid artery (ICA) demonstrated cognitive deficits associated with frontal lobe dysfunction, but the pathophysiological mechanism of memory impairment is not fully understood. This study evaluated relationship between degree of ICA stenosis and frontal activations induced by working memory (WM) task using fMRI. The fMRI data of 21 patients with unilateral ICA stenosis (left/right, 11/10) and 21 controls were analyzed. In comparison with controls, ICA patients demonstrated significant activations in middle frontal gyrus (MFG) bilaterally, particularly in left MFG. In right ICA stenosis, there was slightly less MFG activation than that of controls. Importantly, lower MFG activity was associated with higher stenosis of ipsilateral ICA. For left ICA stenosis, weaker activation in left MFG was negatively correlated with degree of stenosis. Similarly, for right ICA stenosis, there was a significant negative correlation between right ICA stenosis and weaker activation of right MFG. Cognitive impairments in ICA stenosis were associated with frontal lobe dysfunctions. Left ICA stenosis had worse WM impairments than right ICA stenosis, which was affected by the degree of stenosis.