Internal Carotid Artery Peak Systolic Velocity Research Articles

The Association of Arterial Pulse Wave Velocity with Internal Carotid Artery Blood Flow in Healthy Subjects: A Pilot Study

BackgroundArteriosclerosis significantly impacts cardiovascular health. Pulse wave velocity has emerged as a valuable non-invasive method for assessing arterial stiffness. A negative association between carotid-femoral pulse wave velocity (cfPWV) and cerebral blood flow has been reported, suggesting a link between arterial stiffness and reduced cerebral blood flow. We aimed to determine whether a correlation exists between cfPWV and blood flow in the internal carotid artery (ICA) and to assess the influence of age and body mass index (BMI) on cfPWV in healthy individuals.MethodsThirty-six healthy subjects (23 males and 13 females) with no underlying medical conditions and who were not on regular medications were enrolled in the study. Arterial stiffness was assessed by measuring the cfPWV using Vicorder® software. ICA blood flow parameters were measured using high-resolution ultrasound. ICA diameter was measured using automated edge-detection software.ResultsSignificant positive correlations were found between cfPWV and age (Spearman’s rho coefficient 0.33, p = 0.04), BMI (Spearman’s rho coefficient 0.32, p = 0.05), and ICA diameter (Pearson’s coefficient 0.35, p = 0.03). No significant correlations were observed between cfPWV and ICA peak systolic velocities (PSV; p = 0.22), or resistive index (RI; p = 0.76), nor between age and ICA diameter (p = 0.42), PSV (p = 0.09), or RI (p = 0.89).ConclusionOur findings demonstrate a positive correlation between arterial stiffness, age, and BMI in a healthy population, along with an association between increased ICA diameter and arterial stiffness. The lack of correlation between cfPWV and ICA blood flow parameters suggests that the ICA may dilate as a compensatory mechanism to mitigate the effects of increased arterial stiffness, ensuring optimal cerebral blood flow in healthy individuals.

Role of Carotid Ultrasonography Combined with Monocyte/HDL Ratio in Internal Carotid Artery Stenosis.

Carotid duplex ultrasonography (DUS) is the primary screening tool for carotid artery stenosis, but has low reliability. MHR, which is the ratio of monocytes to high-density lipoprotein cholesterol (HDL-C), can be a marker for the degree and distribution of extracranial and intracranial atherosclerotic stenosis. We determined the diagnostic value of DUS+MHR for internal carotid artery (ICA) stenosis. We divided 273 hospitalized patients into non-stenosis (<50%) and ICA stenosis (≥50%) groups based on Digital Subtraction Angiography (DSA). We determined the peak systolic velocity (PSV) in the ICA on DUS, calculated the MHR, and investigated their relationship with ICA stenosis. On DSA, 34.1% (93/273) patients had moderate-to-severe ICA stenosis. DUS and DSA showed low concordance for detecting ICA stenosis (kappa = 0.390). With increasing age, the incidence of moderate-to-severe ICA stenosis increased. PSV, monocyte count, and MHR were significantly greater in the stenosis group than in the non-stenosis group (P < 0.001), while the HDL-C level was significantly lower (P = 0.001). PSV (OR: 1.020, 95% CI: 1.011-1.029, P < 0.001) and MHR (OR: 5.662, 95% CI: 1.945-16.482, P = 0.002) were independent risk factors for ICA stenosis. The area under the receiver operating characteristic curve of PSV+MHR (0.819) was significantly higher than that of PSV or MHR alone (77.42% sensitivity, P = 0.0207; 73.89% specificity, P = 0.0032). The combination of ICA PSV on DUS and MHR is better than PSV alone at identifying ICA stenosis and is well-suited to screen high-risk patients.

Risk factors of in-stent restenosis after carotid angioplasty and stenting: long-term follow-up study.

After carotid artery angioplasty with stenting (CAS), it is unclear which risk factors are related to long-term outcomes, including in-stent restenosis (ISR). This study aimed to assess the factors associated with restenosis after CAS with a median follow-up of 35.7 months. Patients who underwent CAS from January 2013 to December 2018 were included if they had symptomatic or asymptomatic carotid artery stenosis. The carotid Doppler ultrasonography (CDU) was followed up after the procedure. We defined at least 50% restenosis using the criteria that the internal carotid artery (ICA) peak systolic velocity (PSV) was greater than 224 cm/s or the ICA to common carotid artery PSV ratio was higher than 3.4. The risk factors for ISR were also assessed. Of the 189 patients, 122 had symptomatic carotid artery stenosis, and 67 had asymptomatic carotid artery stenosis. Patients were evaluated by CDU for a median of 35.7 months (interquartile range 19.5 to 70.0). Kaplan-Meier analysis showed that the longest time to ISR was 39 months, and ISR-free was better in the asymptomatic CAS group. In all groups, ISR was independently associated with current smoker [adjusted odds ratio (aOR), 3.425; 95% confidence interval (CI), 1.086 to 10.801] and elevated ICA PSV at baseline (aOR, 1.004; 95% CI, 1.001 to 1.007). Independent risk factors for ISR in the CAS group included current smoking and elevated ICA PSV at baseline. In the symptomatic CAS group, alcohol was independently associated with the ISR. ISR did not occur after 39 months from the CAS procedure in our study patients. Future studies with extended follow-up are necessary to fully understand the long-term outcomes of CAS.

Ophthalmic artery reversal predicts contralateral body weakness symptoms better than carotid Doppler velocity-preliminary results.

The measurement of blood velocity in the carotid artery has been the most popular noninvasive method of identifying and classifying carotid stenosis for half a century. Carotid stenosis is an indicator of elevated risk of stroke; anatomic revascularization reduces the chance of stroke by more than half. Controversy persists on how patients with severe carotid stenosis should be selected for anatomic revascularization. Patients with a connected circle of Willis (coW) might not benefit from anatomic revascularization; patients with two segments missing in the coW are most likely to benefit from revascularization. Based on this analysis of data from carotid duplex examinations and transcranial Doppler examinations including ophthalmic artery (OA) direction in 28 patients, a refined carotid examination protocol is proposed. This refinement includes Doppler measurement of OA flow direction and documentation of internal carotid artery (ICA) bruit in addition to the adoption of an ICA peak systolic velocity (PSV) criterion exceeding 350 cm/s for identification of the patient most likely to benefit from carotid stenosis treatment. Sensitivity and specificity of OA direction or carotid bruit are 84.6%±5.4%, 71.4%±2.1% and for PSV >350 cm/s are 84.6%±5.4%, 59.5%±2.3% for predicting contralateral body weakness. The proposed examination can be performed with the same duplex scanner and scan head currently used for carotid examinations with little additional time.

Accuracy of the Society of Radiologists in Ultrasound (SRU) Carotid Doppler Velocity Criteria for Grading North American Symptomatic Carotid Endarterectomy Trial (NASCET) Stenosis: A Meta-Analysis.

The Society of Radiologists in Ultrasound (SRU) consensus panel proposed six Doppler velocity cut points for classifying internal carotid artery (ICA) stenosis of 50% and 70% according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method. Their relative accuracies have not been compared. Meta-analysis performed following comprehensive literature review and identification of manuscripts with graphs of individual patient NASCET ICA stenosis measured by arteriography versus ICA peak-systolic velocity (PSV), end-diastolic velocity (EDV) and ICA PSV to common carotid artery (CCA) PSV. True positives, true negatives, false positives, and false negatives were calculated and used in two-level mixed effects models. Hierarchical summary receiver operating characteristic (ROC) curves were generated. Areas under the ROC curves were estimated. Nine studies performed between 1993 and 2016 were identified after review of 337 manuscripts. There were 1738 bifurcation data points extracted for PSV, 1026 for EDV, and 775 for ICA/CCA ratio. The highest sensitivity was 96% (95% CI: 93%, 98%) for PSV of 125 cm/s (50% stenosis) and highest specificity 86% (95% CI: 71%, 93%) for PSV of 230 cm/s (70% stenosis). Areas under the ROC curves ranged from a high of 0.93 (95% CI: 0.92, 0.95) for PSV (50% stenosis) to a low of 0.86 (95% CI: 0.84, 0.88) for EDV (70% stenosis). The SRU consensus Doppler cut points vary in their accuracies for predicting ICA stenosis. The PSV cut points have tradeoffs: high sensitivity/low specificity for 50% stenosis and high specificity/moderate sensitivity for 70% stenosis.

Analysis of Risk Factors for Vulnerable Plaque Formation and Pathogenic in Carotid Artery.

The formation of vulnerable carotid artery plaque may be closely related to a single factor or caused by multiple factors. This paper discusses the pathogenic risk factors for vulnerable plaque in patients with severe internal carotid artery (ICA) stenosis who received endarterectomy through regression analysis. A total of 98 patients with a complete clinical and laboratory assessment underwent carotid endarterectomy. Metabolic syndrome (MetS) and MetS components, ICA plaque thickness and ICA peak systolic velocity, previous ischemic stroke or transient ischemic attack (TIA), and other risk factors were included in the pathogenic risk factor for vulnerable plaque. Univariate logistic regression analysis was used to determine vulnerable carotid plaque risk factors. If P <0.2, it was considered potential confounders. Binary logistic regression model was controlled for potential confounders. Among the 98 patients, stable carotid plaques 38 (39%) and unstable carotid plaques 60 (61%), male 76 (77.6%) and female 22 (22.4%), and Han Chinese 68 (68.4%) and Mongols 30 (30.6%). Univariate logistic regression to P <0.2 has 6 risk factors, which are previous ischemic stroke or TIA, ICA peak systolic velocity, ICA plaque thickness, body mass index, total cholesterol, and alcohol consumption. The significant result of the binary logistic regression analysis was the previous ischemic stroke or TIA (OR=4.52; 95% CI, 1.67-12.09), P =0.003 and ICA peak systolic velocity (OR=1.01; 95% CI, 1.00-1.02), P =0.014. The patients with previous ischemic stroke or TIA and higher ICA peak systolic velocity are associated with vulnerable plaque pathogenic features. There is no obligatory association between MetS and formation of carotid plaque vulnerability.

Effects of Manual Versus Instrumental Spinal Manipulation on Blood Flow of the Vertebral and Internal Carotid Arteries in Participants With Chronic Nonspecific Neck Pain: A Single-Blind, Randomized Study

ObjectiveThe aim of this study was to compare the hemodynamic effects of manual spinal manipulation (MSM) and instrumental spinal manipulation (ISM) on the vertebral artery (VA) and internal carotid artery (ICA) in participants with chronic nonspecific neck pain (NNP). MethodsThirty volunteers aged 20 to 40 years old with NNP over 3 months duration were included. Participants were randomly divided into the following 2 groups: (1) MSM group (n = 15) and (2) ISM group (n = 15). Ipsilateral (intervention side) and contralateral (opposite side of intervention) VAs and ICAs were evaluated using spectral color Doppler ultrasound before and immediately after manipulation. Measurements were recorded by visualizing the ICA carotid sinus (C4 level) and the VA at the V3 segment (C1-C2 level). The blood flow parameters of peak systolic velocity (PSV), end-diastolic velocity, resistive index, and volume flow (only for VA) were evaluated. The spinal segment, in which biomechanical aberrant movement was detected by palpation in the upper cervical spine, was manually manipulated in the MSM group. The same methodology was performed for the ISM group using an Activator V instrument (Activator Methods). ResultsIntragroup analysis exhibited no statistically significant difference between the MSM and ISM groups in terms of PSV, end-diastolic velocity, resistive index of ipsilateral and contralateral ICA and VA, in addition to volume flow of both VAs preintervention and postintervention (P > .05). Within the intergroup analysis, there was a significant difference in ipsilateral ICA PSV (P = .031) (preintervention vs postintervention difference was –7.9 ± 17.2 cm/s [95% confidence interval, –17.4 to 1.6] in the ISM group and 8.7 ± 22.5 cm/s [95% confidence interval, –3.6 to 21.2]) in the MSM group (P < .05). Other parameters did not show any significant difference (P > .05). ConclusionManual and instrumental spinal manipulations applied to the upper cervical spine in participants with chronic NNP did not appear to alter blood flow parameters of the VAs and ICAs.

Defining Duplex Ultrasound Criteria for In-Stent Restenosis of the Carotid Artery Using Computed Tomographic Angiography.

IntroductionDuplex ultrasound (DUS) velocity measurement is the preferred method for evaluating carotid artery stenosis. However, velocity criteria based upon native carotid arteries may not apply to internal carotid artery stents. Previously, catheter-based angiography was used to determine DUS velocity criteria for in-stent restenosis (ISR), but conventional angiography is invasive and can be limited. This study sought to define duplex ultrasound velocity criteria for predicting internal carotid artery in-stent restenosis by correlating in-stent velocities with computed tomographic angiography (CTA) measurements of percent stenosis.MethodsA retrospective chart review was conducted on all patients who underwent internal carotid artery (ICA) stenting within our health system between January 2013 and February 2020. Thirty-eight surveillance DUS studies from 32 patients were found to have CTA performed within 30 days. Centerline reconstructions of internal carotid artery stents were created using Aquarius iNtuition software (TeraRecon, Durham, NC, USA). Two independent observers measured percent stenosis by three built-in methods. Stenotic areas were matched to DUS-measured peak systolic velocities (PSV) and end-diastolic velocities (EDV). Internal carotid artery PSV (stent) to common carotid artery (CCA) PSV ratios (ICA/CCA) were calculated, and receiver operating characteristic (ROC) curves were generated. The optimal DUS velocity criteria in the stented ICA were determined by maximizing Youden’s index.ResultsMean vessel diameter measurement of percent stenosis resulted in the most accurate model for all DUS velocity parameters (PSV, EDV, and ICA/CCA ratio) and was used for threshold determinations (area under the receiver operating characteristics (AUROC): 0.99, 0.96, and 0.96, respectively). A PSV cutoff of 240 cm/s for ≥60% ISR resulted in the highest Youden’s index (97%) with 100% sensitivity and 97% specificity. Secondary DUS parameters included an EDV ≥50 cm/s (Youden’s index 84%) and an ICA/CCA ratio ≥ 2.2 (Youden’s index 91%).ConclusionsVelocity criteria to predict internal carotid artery ISR is needed to inform decisions for possible reintervention. Using CTA, we found that a PSV ≥240 cm/s on carotid DUS can predict ≥60% ISR with high sensitivity and specificity. This value can be used as an alternative to current velocity criteria based on native carotid arteries. However, the optimal thresholds for EDV and ICA/CCA ratio were similar to native carotid arteries.

A comparative analysis of sonographic carotid artery Doppler indices in type 2 diabetics and non-diabetics

Background and Aim: Diabetes mellitus type 2 is a chronic metabolic disorder of global concern with signs of hyperglycemia due to insulin resistance, relative lack of insulin, or both. Stroke is a possible complication of this metabolic disorder as a result of advanced carotid artery atherosclerosis, which diabetic patients develop with attendant carotid blood flow changes. The present study evaluated sonographic carotid artery blood flow velocities in individuals with type 2 diabetics and compared with values in normoglycemic controls. Materials and Methods: This was a prospective case–control study, in which we evaluated carotid Doppler indices in 125 consenting confirmed type 2 diabetics (cases) and 125 age- and gender-matched normoglycemic healthy controls for a period of 6 months (October 2019 to March 2020). The diabetics (cases) were recruited using systematic sampling method and the controls via convenience sampling. Demographic data and anthropometric measurements as well as ultrasound findings were entered into a Microsoft Office Excel Database and analyzed using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) Version 21. Tables, scatter-plot graphs, and bar charts were used in showing and evaluating the findings. Pearson’s correlation coefficient was used to assess correlation between two continuous variables. Results: The mean age of type 2 diabetics was 67.06±9.8 years, whereas that of the non-diabetics was 66.98±10.7. Females were in majority in both groups (64 in diabetics and 70 in non-diabetics). There were 61 males in the diabetics and 55 males in the non-diabetics. The mean carotid blood flow velocities in the diabetics and non-diabetics were, respectively, as follows: common carotid artery (CCA) end-diastolic velocity (EDV) 21.03±2.3 and 25.22±2.5, CCA peak systolic velocity (PSV) 81.70±4.1 and 83.60±3.6, internal carotid artery (ICA) EDV 17.99±5.6 and 21.57±2.0, ICA PSV 69.30±5.1 and 73.87±2.1, and ICA/CCA PSV ratio 0.83±01 and 0.91±0.1. Conclusion: Type 2 diabetics had significantly lower carotid blood flow velocities than non-diabetics. This suggests that proper management and compliance with care may reduce the development of features of atherosclerosis in type 2 diabetics.

A New Doppler-Derived Parameter to Quantify Internal Carotid Artery Stenosis: Maximal Systolic Acceleration

Doppler ultrasonography (DUS) is used as initial measurement to diagnose and classify carotid artery stenosis. Local distorting factors such as vascular calcification can influence the ability to obtain DUS measurements. The DUS derived maximal systolic acceleration (ACCmax) provides a different way to determine the degree of stenosis. While conventional DUS parameters are measured at the stenosis itself, ACCmax is measured distal to the internal carotid artery (ICA) stenosis. The value of ACCmax in ICA stenosis was investigated in this study. All carotid artery DUS studies of a tertiary academic center were reviewed from October 2007 until December 2017. Every ICA was included once. The ACCmax was compared to conventional DUS parameters: ICA peak systolic velocity (PSV), and PSV ratio (ICA PSV/ CCA PSV). ROC-curve analysis was used to evaluate accuracy of ACCmax, ICA PSV and PSV ratio as compared to CT-angiography (CTA) derived stenosis measurement as reference test. The study population consisted of 947 carotid arteries and was divided into 3 groups: <50% (710/947), 50-69% (109/947), and ≥70% (128/947). Between these groups ACCmax was significantly different. Strong correlations between ACCmax and ICA PSV (R2 0.88) and PSV ratio (R2 0.87) were found. In ROC subanalysis, the ACCmax had a sensitivity of 90% and a specificity of 89% to diagnose a ≥70% ICA stenosis, and a sensitivity of 82% and a specificity of 88% to diagnose a ≥50% ICA stenosis. For diagnosing a ≥50% ICA stenosis the area under the curve (AUC) of ACCmax (0.88) was significantly lower than the AUC of PSV ratio (0.94) and ICA PSV (0.94). To diagnose a ≥70% ICA stenosis there were no significant differences in AUC between ACCmax (0.89), PSV ratio (0.93) and ICA PSV (0.94). ACCmax is an interesting additional DUS measurement in determining the degree of ICA stenosis. ACCmax is measured distal to the stenosis and is not hampered by local distorting factors at the site of the stenosis. ACCmax can accurately diagnose an ICA stenosis, but was somewhat inferior compared to ICA PSV and PSV ratio to diagnose a ≥50% ICA stenosis.

Carotid artery duplex velocity criteria might be equivocal after left ventricular assist device implantation

BackgroundAlthough conventional angiography remains the reference standard for the grading of carotid stenosis, carotid duplex ultrasound (CDUS) is the most commonly used modality for determining the degree of carotid stenosis. The validity of CDUS findings for patients after left ventricular assist device (LVAD) implantation is questionable, because the velocities are often altered secondary to the continuous flow nature of the devices. MethodsA retrospective review was performed of all patients who had undergone LVAD implantation from January 2007 to December 2019. All patients who had undergone CDUS before and after LVAD implantation were included. Patients receiving extracorporeal membrane oxygenation, those with unusable carotid imaging studies, and those with internal carotid artery (ICA) occlusion were excluded. The peak systolic velocity (PSV) and end-diastolic velocity (EDV) in the ICA and common carotid artery (CCA) and the ICA/CCA ratios were compared before and after LVAD implantation. ResultsA total of 36 patients (mean age 59 years; 30 men; 6 women) had undergone CDUS both before and after LVAD implantation (mean, 647 days between imaging studies). A total of 61 ICAs had met the criteria for inclusion. Before LVAD, 7 carotid arteries (13%) had had >50% carotid stenosis and 53 (87%) had had 0% to 50% stenosis. The mean changes in the velocities after LVAD were as follows. The ICA PSV had decreased by 6.12 ± 4.34 cm/s, and the ICA EDV had increased by 13.44 ± 4.23 cm/s. The CCA PSV had decreased by 17.22 ± 4.95 cm/s, and the CCA EDV had increased by 10.83 ± 2.59 cm/s. The mean ICA/CCA ratio had increased by 0.18 ± 0.05. All the mean changes in velocity were significant (P < .01), except for the ICA PSV (P = .167). Among four patients with known stenosis of 60% to 69%, the degree of increase in the ICA and CCA EDVs (75.8 and 13.3 cm/s, respectively) was significantly greater than that for patients with <50% or no stenosis. Carotid artery laterality did not significantly affect the differences in mean velocity. Centrifugal LVADs resulted in a significantly larger increase in the ICA EDV compared with axial LVADs (26.0 vs 6.3 cm/s; P < .01). ConclusionsLVADs were associated with significant changes in CCA PSV, ICA and CCA EDV, and ICA/CCA ratios. However, the magnitude of these changes in patients with <50% stenosis was minimal and might not be clinically significant. The LVAD type might only have an effect on EDV measurements in the CCA, and the left and right carotid arteries did not appear to have different degrees of change in velocity. The currently used criteria for determining carotid stenosis might result in an under- or overestimation of carotid stenosis in patients with an LVAD.

Are systolic velocity duplex metrics negatively affected by flow aliasing in areas of critical internal carotid artery stenosis

ABSTRACTPurpose: Duplex scanning is a useful noninvasive screening tool for the detection of carotid bifurcation disease. Internal carotid artery (ICA) peak systolic velocity (PSV) and ICA/common carotid artery (CCA) PSV ratios are proven metrics determining 70%-99% ICA stenosis. A potential disadvantage of using dramatically increasing systolic velocity measurements in areas of critical arterial stenosis is flow aliasing. Diastolic velocity should be less influenced by this flow artifact. We evaluate ICA and CCA end diastolic velocity (EDV) metrics in predicting severe ICA stenosis and document the prevalence of an aliasing artifact in a population of patients with critical ICA stenosis.Methods: Consecutive patients undergoing carotid duplex assessments and contrast angiography were compared (n = 140). ICA and CCA PSV and EDV were recorded as was evidence of the flow aliasing of ICA waveforms. ICA/CCA PSV and EDV ratios were calculated. Duplex parameters were compared with angiographic ICA measurements. Receiver-operator characteristic curve (ROC) analysis was used to determine optimal criteria to identify ICA stenosis of 70% to 99%.Results: Of 256 carotid bifurcation duplex studies, critical angiographic stenosis was present in 105 arteries. Only four completed arterial duplex scans demonstrated flow aliasing. In three of these patients, systolic metrics were non-diagnostic versus ICA/CCA EDV ratios. An ICA/CCA EDV ratio of 2.3 provided the best combination of sensitivity 73.8% and specificity 75.18%.Conclusion: ICA/CCA diastolic ratios reliably determine 70% or greater ICA stenosis. Flow aliasing infrequently complicates ICA PSV.

Abstract WP163: From Static Imaging to Hemodynamic Modelling: Automated Nascet Grading Using Computational Fluid Dynamics

Aim: Duplex ultrasound is used for non-invasive assessment of internal carotid artery (ICA) disease and stenosis grading based on The North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria. Computational fluid dynamics (CFD) can be used to model blood flow based on static scans (like CT or MR angiograms), but such models are rarely validated in real clinical settings. We evaluated the accuracy of an automated vascular analysis software that simulates blood flow given a CT or MR angiogram (See-Mode Technologies, Singapore) against NASCET grading done by duplex ultrasound. Methods: 20 carotid arteries from patients with ICA disease were retrospectively analyzed using an automated vascular analysis software according to a blinded protocol. Three-dimensional models of the carotid arteries were reconstructed from MR or CT angiogram DICOM images, and CFD was used for patient-specific modelling of blood flow in the vasculature. Blood flow velocities, specifically ICA peak systolic velocity (PSV) and PSV ratio between the ICA and the common carotid artery (CCA) were obtained from the software and used for stenosis grading based on the NASCET criteria. Bland-Altman analysis was used to assess the agreement between the software and duplex ultrasound. Results: The blood flow simulations were in excellent agreement with duplex ultrasound for both metrics, i.e. ICA PSV (r 2 = 0.936, P &lt; 0.001) and ICA/CCA PSV ratio (r 2 = 0.932, P &lt; 0.001). There was no significant over or under estimation of ICA PSV, but there was a slight over estimation of the ICA/CCA PSV ratio with the software (ICA PSV: bias = 5 cm/s, lower limit of agreement (LOA) = -43 cm/s, upper LOA = 52 cm/s; ICA/CCA PSV ratio: bias = 0.16, lower LOA = -0.54, upper LOA = 0.86). All carotid arteries were correctly classified with the software compared against the NASCET grading done with duplex ultrasound. Conclusion: While CFD is commonly used for modelling blood flow, its accuracy is rarely assessed in real clinical settings. This is the first validated comparison of carotid artery stenosis grading using blood flow simulations against duplex ultrasound. When the data was categorized according to NASCET criteria, all cases were correctly classified with the software compared against duplex ultrasound.

Accuracy of Carotid Duplex Criteria in Diagnosis of Significant Carotid Stenosis in Asian Patients

Extracranial carotid stenosis can be diagnosed by velocity criteria of carotid duplex. Whether they are accurately applied to define severity of internal carotid artery (ICA) stenosis in Asian patients needs to be proved. The purpose of this study was to evaluate the accuracy of 2 carotid duplex velocity criteria in defining significant carotid stenosis. Carotid duplex studies and magnetic resonance angiography were reviewed. Criteria 1 was recommended by the Society of Radiologists in Ultrasound; moderate stenosis (50%-69%): peak systolic velocity (PSV) 125-230 cm/s, diastolic velocity (DV) 40-100 cm/s; severe stenosis (>70%): PSV greater than 230 cm/s, DV greater than 100 cm/s. Criteria 2 used PSV greater than 140 cm/s, DV less than 110 cm/s to define moderate stenosis (50%-75%) and PSV greater than 140 cm/s, DV greater than 110 cm/s for severe stenosis (76%-95%). A total of 854 ICA segments were reviewed. There was moderate stenosis in 72 ICAs, severe stenosis in 50 ICAs, and occlusion in 78 ICAs. Criteria 2 had slightly lower sensitivity, whereas higher specificity and accuracy than criteria 1 were observed in detecting moderate stenosis (criteria 1: sensitivity 95%, specificity 83%, accuracy 84%; criteria 2: sensitivity 92%, specificity 92%, and accuracy 92%). However, in detection of severe ICA stenosis, no significant difference in sensitivity, specificity, and accuracy was found (criteria 1: sensitivity 82%, specificity 99.57%, accuracy 98%; criteria 2: sensitivity 86%, specificity 99.68%, and accuracy 99%). In the subgroup of moderate stenosis, the criteria using ICA PSV greater than 140 cm/s had higher specificity and accuracy than the criteria using ICA PSV 125-230 cm/s. However, there was no significant difference in detection of severe stenosis or occlusion of ICA.

Common carotid artery end-diastolic velocity and acceleration time can predict degree of internal carotid artery stenosis

ObjectiveWhereas duplex ultrasound parameters for predicting internal carotid artery (ICA) stenosis are well defined, the use of common carotid artery (CCA) Doppler characteristics to predict ICA stenosis when the ICA cannot be insonated directly or accurately because of anatomy, calcification, or tortuosity has not been studied. The objective of this study was to identify CCA Doppler parameters that may predict ICA stenosis. MethodsWe reviewed all patients at our institution who underwent carotid duplex ultrasound (CDU) from 2008 to 2015 and also had a comparison computed tomography, magnetic resonance, or catheter angiogram. We excluded patients whose CDU examination did not correlate with the comparison study, those whose arteries were not visualized on the comparison study, and those with complete occlusion of the CCA. We collected CCA peak systolic velocity (PSV), end-diastolic velocity (EDV), and acceleration time (AT) in addition to CDU and comparison imaging interpretation of degree of stenosis. A multivariate model was used to identify predictors of ICA stenosis. ResultsThere were 99 CDU examinations with corresponding comparison imaging included. For every increase of 10 cm/s in EDV in the CCA, the odds of a >50% ICA stenosis being present vs a ≤50% ICA stenosis decreased by 37% (odds ratio [OR], 0.63; 95% confidence interval [CI], 0.41-0.97; P = .03). For every increase of 10 cm/s in EDV in the CCA, the odds of a 70% to 99% ICA stenosis being present vs a ≤50% ICA stenosis decreased by 48% (OR, 0.52; 95% CI, 0.28-0.94; P = .03). A CCA EDV of 19 cm/s or below was associated with a 64% probability of a 70% to 99% ICA stenosis. For every 50-millisecond increase in AT in the CCA, the odds of a >50% stenosis being present vs a ≤50% ICA stenosis increased by 56% (OR, 1.56; 95% CI, 1.03-2.35; P = .04). A CCA AT of 80 milliseconds or above was associated with a 69% probability of a >50% ICA stenosis. There was no correlation between CCA PSV and ICA stenosis. ConclusionsCCA EDV and AT are independent predictors of ICA stenosis and may be used in the setting of patients whose ICA cannot be directly insonated or when standard duplex ultrasound parameters of ICA PSV, EDV, or ICA/CCA ratio conflict.

Carotid endarterectomy should not be based on consensus statement duplex velocity criteria

ObjectiveRandomized trials support carotid endarterectomy (CEA) in asymptomatic patients with ≥60% internal carotid artery (ICA) stenosis. The widely referenced Society for Radiologists in Ultrasound Consensus Statement on carotid duplex ultrasound (CDUS) imaging indicates that an ICA peak systolic velocity (PSV) ≥230 cm/s corresponds to a ≥70% ICA stenosis, leading to the potential conclusion that asymptomatic patients with an ICA PSV ≥230 cm/s would benefit from CEA. Our goal was to determine the natural history stroke risk of asymptomatic patients who might have undergone CEA based on consensus statement PSV of ≥230 cm/s but instead were treated medically based on more conservative CDUS imaging criteria. MethodsAll patients who underwent CDUS imaging at our institution during 2009 were retrospectively reviewed. The year 2009 was chosen to ensure extended follow-up. Asymptomatic patients were included if their ICA PSV was ≥230 cm/s but less than what our laboratory considers a ≥80% stenosis by CDUS imaging (PSV ≥430 cm/s, end-diastolic velocity ≥151 cm/s, or ICA/common carotid artery PSV ratio ≥7.5). Study end points included freedom from transient ischemic attack (TIA), freedom from any stroke, freedom from carotid-etiology stroke, and freedom from revascularization. ResultsCriteria for review were met by 327 patients. Mean follow-up was 4.3 years, with 85% of patients having >3-year follow-up. Four unheralded strokes occurred during follow-up at <1, 17, 25, and 30 months that were potentially attributable to the index carotid artery. Ipsilateral TIA occurred in 17 patients. An additional 12 strokes occurred that appeared unrelated to ipsilateral carotid disease, including hemorrhagic events, contralateral, and cerebellar strokes. Revascularization was undertaken in 59 patients, 1 for stroke, 12 for TIA, and 46 for asymptomatic disease. Actuarial freedom from carotid-etiology stroke was 99.7%, 98.4%, and 98.4% at 1, 3, and 5 years, respectively. Freedom from TIA was 98%, 96%, and 95%, freedom from any stroke was 99%, 96%, and 93%, and freedom from revascularization was 95%, 86%, and 81% at 1, 3, and 5 years, respectively. ConclusionsPatients with intermediate asymptomatic carotid stenosis (ICA PSV 230-429 cm/s) do well with medical therapy when carefully monitored and intervened upon using conservative CDUS criteria. Furthermore, a substantial number of patients would undergo unnecessary CEA if consensus statement CDUS thresholds are used to recommend surgery. Current velocity threshold recommendations should be re-evaluated, with potentially important implications for upcoming clinical trials.

Simplified ultrasound protocol for the exclusion of clinically significant carotid artery stenosis

Objectives: To evaluate a simplified ultrasound protocol for the exclusion of clinically significant carotid artery stenosis for screening purposes.Material and methods: A total of 9,493 carotid arteries in 4,748 persons underwent carotid ultrasound examination. Most subjects were 65-year-old men attending screening for abdominal aortic aneurysm. The presence of a stenosis on B-mode and/or a mosaic pattern in post-stenotic areas on colour Doppler and maximum peak systolic velocity (PSV) in the internal carotid artery (ICA) were recorded. A carotid stenosis was defined as The North American Symptomatic Carotid Endarterectomy Trial (NASCET) >20% and a significant stenosis as NASCET >50%. The kappa (κ) statistic was used to assess agreement between methods. Sensitivity, specificity, positive predictive (PPV), and negative predictive (NPV) values were calculated for the greyscale/mosaic method compared to conventional assessment by means of PSV measurement.Results: An ICA stenosis was found in 121 (1.3%) arteries; 82 (0.9%) were graded 20%–49%, 16 (0.2%) were 50%–69%, and 23 (0.2%) were 70%–99%. Eighteen (0.2%) arteries were occluded. Overall, the greyscale/mosaic protocol showed a moderate agreement with ICA PSV measurements for the detection of carotid artery stenosis, κ = 0.455. The sensitivity, specificity, PPV, and NPV for detection of >20% ICA stenosis were 91% (95% CI 0.84–0.95), 97% (0.97–0.98), 31% (0.26–0.36), and 97% (0.97–0.97), respectively. The corresponding figures for >50% stenosis were 90% (0.83–0.95), 97% (0.97–0.98), 11% (0.08–0.15), and 100% (0.99–1.00).Conclusion: Compared with PSV measurements, the simplified greyscale/mosaic protocol had a high negative predictive value for detection of >50% carotid stenosis, suggesting that it may be suitable as a screening method to exclude significant disease.

Progression of moderate-to-severe carotid disease

Our goals were to investigate the degree to which patient demographics, risk factors, laboratory data, and medications influence moderate carotid disease progression among patients with asymptomatic moderate carotid disease and whether such associations are solely based on how progression is defined. In addition, we aimed to establish optimal threshold criteria to categorize patients at high risk of progression. In this retrospective study, 621 arteries were evaluated for internal carotid artery (ICA) stenosis between January 1997 and January 2014 and were determined to have moderate (50%-79%) stenosis via color duplex ultrasonography. "Moderate stenosis" was defined as an ICA peak systolic velocity (PSV) ≥120cm/s and a diastolic ICA velocity<140cm/s. Kaplan-Meier analysis of the time to progression was conducted using three independent end points: PSV ≥230cm/s (liberal criterion); ICA/common carotid artery (CCA) ratio ≥4.0 (moderate criterion), and diastolic ICA velocity ≥140cm/s (strict criterion). Kaplan-Meier survival curves were generated, and multivariate analysis was performed using Cox regression models. Risk stratification criteria were based on optimal sensitivity and specificity generated from receiver operating characteristic (ROC) curve analysis. The overall rate of progression was 28.5%, 21.1%, or 5.1% of study-eligible arteries over 5years using liberal, moderate, or strict criterion, respectively. Using liberal criterion, multivariate analysis suggested that initial PSV ≥200cm/s, ICA/CCA ratio ≥3, and male gender were significantly associated with progression. Using the moderate criterion, multivariate analysis revealed that initial PSV ≥200cm/s, ICA/CCA ratio ≥3, age, and male gender were significantly associated with progression. Using the strict criterion, multivariate analysis revealed that initial PSV ≥200cm/s was the only statistically significant predictor of progression. No additional patient demographics, comorbidities, initial laboratory values, or medications consistently influenced disease progression across any criteria in our study. ROC analysis suggests PSV ≥165cm/s is an ideal threshold value for the categorization of high risk patients, as this resulted in an optimal screening sensitivity of nearly 91% and a specificity of 59% over 2years. The timing and incidence of carotid disease progression depends on the definition of disease progression. Among all three criteria, only severity of disease at initial presentation reliably predicted progression. Based on the results of our ROC curve analysis, we propose that an initial ICA PSV ≥165cm/s (sensitivity: 90.7%, specificity: 58.7%) represents a reasonable value for defining high progression risk over a 2-year interval.

Should Carotid Duplex Velocity Thresholds be Modified for Patients Undergoing Computed Tomographic Angiography?

Purpose The use of computed tomographic angiography (CTA) has increased dramatically whereas angiography (ANGIO) has decreased proportionally. The purpose of this study is to evaluate the impact of this trend on internal carotid artery (ICA) ultrasound velocity criteria in the vascular laboratory. Methods Carotid duplex quality assurance (QA) databases were queried for similar cohorts of CTA and ANGIO ≥50% and ≥70% stenoses. Optimal velocity thresholds, sensitivity and specificity for ICA peak systolic velocity (PSV), end-diastolic velocity (EDV), peak systolic ICA, and common carotid artery ratio (carotid ratio) were obtained for CTA and ANGIO groups. Results A total of 101 vessels were analyzed in each group. Optimal PSV threshold, sensitivity, and specificity for CTA ≥50% stenosis was 152 cm/sec, 92.1% and 94.9% and for ANGIO, 170 cm/sec, 85.9% and 91.9%, respectively. When the optimal PSV threshold for the ANGIO group was applied to the CTA group, sensitivity and specificity were 85.7% and 94.7%, respectively. In the CTA group, PSV threshold was significantly lower when used to diagnose the ANGIO group ≥50% stenosis ( p = 0.0001). Optimal PSV, EDV, and PSV ratio thresholds for CTA ≥70% stenosis were 230 cm/sec, 62 cm/sec, and 2.7 and for ANGIO, 230 cm/sec, 68 cm/sec, and 3.2. Although no PSV differences were noted, when optimal EDV and PSV ratio thresholds for ANGIO ≥70%were applied to CTA ≥70%, EDV sensitivity and specificity were 80.9% and 94.7%, PSV ratio, 78.7% and 92.6%, respectively. CTA EDV and PSV ratio thresholds were statistically lower when used to diagnose ANGIO &gt;70% stenosis ( p = 0.0001). Conclusions Optimal PSV threshold for ≥50% and EDV and PSV ratio thresholds for ≥70% ANGIO stenosis were lower, with significant differences in sensitivity and specificity found, when used to diagnose similar CTA stenoses. Modifying angiography-based carotid duplex velocity criteria may be warranted for patients who are evaluated with CTA.

Abstract 19470: Predicted Impact of Carotid Artery Atherosclerotic Disease for Screening of Abdominal Aortic Aneurysm in Women

Introduction: Screening of abdominal aortic aneurysm (AAA) for women has not been established. The aim of this study was to determine the predictive factors associated with ultrasonographic screening for AAA in patients who receive coronary angiogram (CAG) for suspicion of coronary artery disease (CAD). Methods: Study patients were consisted with 310 consecutive women over 65 years undergoing initial CAG. Both abdominal and carotid arterial ultrasonography were performed for all patients. Patients with known AAA were excluded in this study. AAA was defined as abdominal aortic diameter ≥30 mm by ultrasonographic examination. Carotid artery atherosclerotic disease (CAAD) was defined as a ≥50% stenosis of internal carotid artery (ICA) in NASCET criteria or ≥150cm/sec of ICA peak systolic velocity. Ankle branch pressure index (ABI) was also performed for all patients, and peripheral arterial disease (PAD) was defined as a ≤0.9 of ABI. CAD was defined as a ≥75% reduction in diameter in at least one major vessel in coronary angiography. Multivariate logistic regression analysis was used to study multiple risk factors (age, hypertension, diabetes, dyslipidemia, smoking, hemodialysis, cerebral infarction, CAD, CAAD and PAD) for AAA. Results: Of 310 patients, incidental AAA was detected in 10 patients (3.2%) and 1 had AAA diameter of ≥50mm. Patients with CAD included higher prevalence of AAA than those without (5.6% vs 0.7%, P=0.021). Multivariate analysis revealed that age (RR 1.3, 95% CI 1.1 to 1.5, p = 0.001) and CAAD (RR 8.5, 95% CI 1.3 to 55.7, p= 0.025) were significantly associated with a higher prevalence of AAA. Conclusions: Older age and presence of CAAD should be taken into account as a possible criterion for selective AAA ultrasonographic screening in women over 65 years for suspicion of CAD.