Carotid Artery Peak Systolic Velocity Research Articles

RS07. The Incidence of Carotid In-Stent Stenosis Is Underestimated: Is It 50% or 80% and Its Clinical Implications

The incidence of carotid in-stent stenosis has been reported to vary between 1% and 30%. Most published studies have relatively short follow-up periods, which may lead to underestimating the incidence of carotid in-stent stenosis rates. This study analyzed the incidence of 50% and 80% carotid in-stent restenosis using validated duplex velocity criteria and its clinical implications. This retrospective analysis included prospectively collected data from 450 carotid artery stent (CAS) procedures. All patients had postoperative carotid duplex ultrasound examination, which was repeated at 1 month, 6 months, and every 6 to 12 months thereafter. A Kaplan-Meier analysis was used to estimate the freedom rates from 50% in-stent restenosis (internal carotid artery peak systolic velocity of 224 cm/s) and 80% in-stent restenosis (internal carotid artery peak systolic velocity of 325 cm/s) and its clinical implications. The mean age was 68.3 years, with a mean follow-up of 40.3 months. A total of 201 of 450 patients (45%) underwent CAS for symptomatic disease. Primary CAS was done in 291 patients (65%) and the remaining 35% were done for post-CEA stenosis. A total of 101 patients (23%) had 50% late carotid in-stent restenosis, and of these, 33 (7.4%) had 80% in-stent restenosis. Nineteen patients (4.3%) developed late transient ischemic attack and three (0.7%) late stroke. Twenty-three (5.2%) patients had late reintervention. Rates of freedom from 50% in-stent restenosis in the whole series were 85%, 79%, 75%, 72%, and 70% at 1, 2, 3, 4, and 5 years, respectively (Fig 1). The rates of freedom from 50% in-stent restenosis for primary CAS and CAS for post-CEA restenosis were not statistically significant (P = .540). The rates of freedom from 80% in-stent restenosis for the whole series were 96%, 95%, 93%, 90%, and 89% at 1, 2, 3, 4, and 5 years, respectively (Fig 2). The rates of freedom from 80% in-stent restenosis for primary CAS and CAS for post-CEA restenosis, were also not significant (P = .516). The rates of freedom from reintervention were 98%, 96%, 93%, 93%, and 91% at 1, 2, 3, 4, and 5 years, respectively, and there were no differences between primary CAS and CAS for post-CEA stenosis (P = .939). The overall late survival rates were 99%, 97%, 96%, 94%, and 91% at 1, 2, 3, 4, and 5 years, respectively. The incidence of 50% in-stent restenosis is relatively high; however, the rates of 80% restenosis and late neurologic events are low.Fig 2Freedom from >80% restenosis.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

12주간 복합운동이 비만 성인여성의 경동맥 순응도 및 수축기 혈류속도와 내경 비에 미치는 영향

12주간 복합운동이 비만 성인여성의 경동맥 순응도 및 수축기 혈류속도와 내경 비에 미치는 영향

B-Flow and B-Mode Ultrasound Imaging in Carotid Fibromuscular Dysplasia.

Previous ultrasound studies in fibromuscular dysplasia (FMD) have largely reported on color flow imaging, power Doppler, and Doppler flow augmentation. We here report on arterial wall imaging findings by B-flow and B-mode in patients with carotid FMD. We retrospectively reviewed ultrasonographic findings in subjects with known or suspected FMD. All patients were evaluated with a standardized imaging protocol including Doppler, B-mode, and B-flow. Vessel wall abnormalities were classified as normal, luminal irregularities, or classical beading (fusiform dilatations). We identified 23 patients and 33 carotid arteries were found to be abnormal, of which 10 had classical beading and 23 showed endoluminal irregularities. Bilateral disease was present in 10/23 patients. In the classical beading cases, B-mode revealed isoechoic ridges, which protruded into the lumen, alternating with dilated arterial segments, which were also clearly demonstrated by B-flow imaging. In cases with endoluminal irregularities, B-mode and B-flow showed isoechoic subendothelial irregular thickening, which did not lead to a fusiform dilatory appearance of the artery. The average distal internal carotid artery peak systolic velocity of arteries with classical beading (123 ± 29 cm/second) was significantly greater than that of arteries with mild irregularities (94 ± 34 cm/second) (P = .024). Morphological arterial wall changes of FMD were well depicted by careful B-flow and B-mode imaging of the distal internal carotid artery. We would like to emphasize the utility of B-flow and B-mode in the noninvasive evaluation of FMD.

A comparison of carotid doppler ultrasonography and capnography in evaluating the efficacy of CPR

Introduction and purposeThe end-tidal carbon dioxide (ETCO2) measurement is accepted as the gold standard method for assessing cardiopulmonary resuscitation (CPR) efficacy. In recent studies, the use of Carotid Doppler Ultrasonography has become widespread in showing CPR efficacy. In the present study, the carotid blood flow measurement was compared with ETCO2 measurement and an evaluation was made of whether this method could be used as an alternative method to capnography in the assessment of CPR efficacy. Material and methodThis study was conducted on patients who presented at the Emergency Department (ED) with non-traumatic arrest or began to suffer from arrest during emergency service follow-up. The main carotid artery peak systolic velocity (PSV), end diastolic velocity (EDV) and time-dependent mean flow velocity (MNV), and ETCO2 values were measured and recorded after the 100th chest pressure of the CPR cycle and the results were statistically analyzed. ResultsThe mean age of the patients was 54.5±12.3years and 65.6% of the patients were male. The mean values of patients measured from the carotid artery during the CPR were PSV 67.1±17.3, EDV 16.3±4.5, MNV 25.5±8.1 and ETCO2 22.2±8.1. A significant difference was found between in-hospital and out-of-hospital arrests in terms of patient outcome (return of spontaneous circulation (ROSC) and death) (p<0.05). The mean ETCO2 values of those who died were found to be lower than those of the ROSC group (p<0.05). Although there was a positive and low-level of correlation between the ETCO2 values and PSV values, and a positive and very low-level of correlation between the EDV and MNV values of all patients, these correlations were not statistically significant. (p>0.05). ConclusionA low correlation was found between the PSV and ETCO2 values. With effective CPR, the results close to carotid blood flow in normal healthy individuals were obtained. However, the study showed that carotid blood flow measurement results during CPR were not as valuable as ETCO2 in demonstrating CPR efficacy.

Case of Asymptomatic Carotid Artery Stenosis in a Hypertensive Patient

This is the case of a hypertensive patient with an asymptomatic carotid stenosis. This is a very common situation that neurologists have to manage. The case is a 75-year-old man with an history of hypertension for 10 years, treated with amlodipine, 5 mg once a day, and perindopril, 8 mg once a day. His hypertension was considered to be controlled. He was also treated for a hyperlipidemia for 5 years with atorvastatin, 10 mg, once a day. His general practitioner recommended an echo-Doppler of cervical and intracranial arteries as part of a systematic screening because of his vascular risk factors. Echo-Doppler showed an atherosclerotic stenosis at the site of the left carotid bifurcation. On grayscale, this stenosis was characterized as a uniformly echogenic plaque (homogeneous plaque). On sonographic NASCET index (North American Symptomatic Carotid Endarterectomy Trial), there was a peak systolic velocity increase of 280 cm/s that translated to a high internal carotid artery/common carotid artery peak systolic velocity ratio of 4.5. Morphology and hemodynamic data were consistent with a severe carotid stenosis estimated about 70% per NASCET criteria. A computed tomographic angiography, already planned by the general practitioner, confirmed a calcified severe stenosis of the bifurcation. The degree of narrowing was also estimated to be about 70% according to NASCET criteria. Contralateral internal carotid artery and intracranial arteries were normal. Arterial work-up was consistent with an isolated severe asymptomatic left carotid stenosis. The patient had no previous history of cerebral vascular disease. His neurological examination was normal. His blood pressure was slightly elevated with systolic blood pressure of 160 mm Hg and a diastolic blood pressure of 95 mm Hg. His recent blood sample showed low-density lipoprotein cholesterol <1 g/L, and his glomerular filtration rate was normal. This case addresses several issues, in particular estimation of the absolute risk of ischemic …

Internal carotid artery velocities in patients with unilateral non-arteritic anterior ischemic optic neuropathy

Objective: This study aims to evaluate and compare the proximal, medial, and distal segments of internal carotid artery (ICA) peak systolic velocities (PSV) in patients with nonarteritic anterior ischemic optic neuropathy (NA-AION) in one eye against the contralateral side with normal eye findings using doppler ultrasound. Methods: This is a single-center, prospective, case control study of five patients with unilateral NA-AION. The peak systolic velocity (PSV) of the proximal, medial, and distal segments of the ICAs on both sides, one side with NA-AION while the contralateral side had normal eye findings, were compared and analyzed. Results: Four females and one male with a mean age of 59 years (SD = 17 years) were included. PSV of the ICA was measured in three segments: Proximal (PICA), Medial (MICA), and Distal (DICA). Mean PSV of eyes with NA-AION was 143cm/sec (SD= 177cm/sec), 159 cm/sec (SD=189 cm/sec), 98 cm/sec (SD=34cm/sec) for PICA, MICA and DICA respectively. Mean PSV of contralateral side without NA-AION was 95cm/sec (SD= 72cm/sec), 101 cm/sec (SD=53cm/sec), 140cm/sec (SD=60 cm/sec) for PICA, MICA and DICA respectively. There was no statistically significant difference between the two groups along the three segments (T-test PICAp=0.369, MICAp=0.402, DICAp=0.112). Conclusion: Mean PSV was higher in eyes with NA-AION at the proximal and medial segments of the ICA, while it was lower at the distal segments compared to the contralateral non-NA-AION side.

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.

Development of a Duplex Ultrasound Simulator and Preliminary Validation of Velocity Measurements in Carotid Artery Models.

Duplex ultrasound scanning with B-mode imaging and both color Doppler and Doppler spectral waveforms is relied upon for diagnosis of vascular pathology and selection of patients for further evaluation and treatment. In most duplex ultrasound applications, classification of disease severity is based primarily on alterations in blood flow velocities, particularly the peak systolic velocity (PSV) obtained from Doppler spectral waveforms. We developed a duplex ultrasound simulator for training and assessment of scanning skills. Duplex ultrasound cases were prepared from 2-dimensional (2D) images of normal and stenotic carotid arteries by reconstructing the common carotid, internal carotid, and external carotid arteries in 3 dimensions and computationally simulating blood flow velocity fields within the lumen. The simulator displays a 2D B-mode image corresponding to transducer position on a mannequin, overlaid by color coding of velocity data. A spectral waveform is generated according to examiner-defined settings (depth and size of the Doppler sample volume, beam steering, Doppler beam angle, and pulse repetition frequency or scale). The accuracy of the simulator was assessed by comparing the PSV measured from the spectral waveforms with the true PSV which was derived from the computational flow model based on the size and location of the sample volume within the artery. Three expert examiners made a total of 36 carotid artery PSV measurements based on the simulated cases. The PSV measured by the examiners deviated from true PSV by 8% ± 5% (N = 36). The deviation in PSV did not differ significantly between artery segments, normal and stenotic arteries, or examiners. To our knowledge, this is the first simulation of duplex ultrasound that can create and display real-time color Doppler images and Doppler spectral waveforms. The results demonstrate that an examiner can measure PSV from the spectral waveforms using the settings on the simulator with a mean absolute error in the velocity measurement of less than 10%. With the addition of cases with a range of pathologies, this duplex ultrasound simulator will be a useful tool for training health-care providers in vascular ultrasound applications and for assessing their skills in an objective and quantitative manner.

Common carotid artery peak systolic velocity ratio predicts high-grade common carotid stenosis

Screening for common carotid artery (CCA) stenosis with duplex ultrasound (DUS) velocity criteria alone can be limited by within-patient and between-patients hemodynamic variability. This study aimed to evaluate inter-CCA velocity ratio criteria to predict high-grade CCA stenosis. This was a retrospective review of consecutive patients who underwent computed tomography angiography and DUS peak systolic velocity (PSV) measurements of bilateral CCAs, independently recorded, between 2008 and 2014. Patients with dampened CCA waveforms on DUS composed group B. The remainder without dampened waveforms constituted group A. Inter-CCA PSV ratios were calculated by dividing the higher CCA PSV by the lower one of the other side, so the ratios would always be ≥1. Ratios were subsequently paired with each respective unilateral CCA diameter stenosis and differential bilateral CCA diameter stenosis. A quadratic regression model was fitted to predict unilateral and differential stenosis. Receiver operating characteristic curve was used to determine optimal ratios for ≥50% and ≥80% CCA stenosis. The study excluded patients with carotid artery occlusion. From a total of 201 patients, 193 patients were included in group A and 8 in group B. Within group A, 31 patients had ≥50% unilateral stenosis and 17 had ≥50% differential stenosis. All stenoses ≥50% were identified on the same side with the higher PSV. Inter-CCA PSV ratio predicted ≥50% unilateral (r(2) = 0.536; P < .001) and differential stenosis (r(2) = 0.581; P < .001). In group B, all patients had ≥60% stenosis that was near or involved the vessel origin. An increasing inter-CCA PSV ratio showed a trend toward contralateral high-grade stenosis (r(2) = 0.596; P = .1). Receiver operating characteristic curves showed an optimal threshold CCA ratio ≥2.16 for ≥50% unilateral stenosis with 92% accuracy, 62% sensitivity, and 98% specificity (area under curve = 0.854; 95% confidence interval, 0.759-0.948) and a ratio ≥2.62 for ≥50% differential stenosis with 97% accuracy, 83% sensitivity, and 98% specificity (area under curve = 0.94; 95% confidence interval, 0.835-1). DUS-based CCA PSV ratio can accurately predict unilateral and differential high-grade CCA stenosis. Also, in patients with unilateral dampened waveforms, it implied contralateral severe proximal stenosis. This parameter should be further validated in prospective studies and may serve as an adjunct screening tool to detect high-grade CCA stenosis.

Comparison of Carotid Artery Blood Velocity Measurements by Vector and Standard Doppler Approaches

Although severely affected by the angle dependency, carotid artery peak systolic velocity measurements are widely used for assessment of stenosis. In this study, blood peak systolic velocities in the common and internal carotid arteries of both healthy volunteers and patients with internal carotid artery stenosis were measured by two vector Doppler (VD) methods and compared with measurements obtained with the conventional spectral Doppler approach. Although the two VD techniques were completely different (using the transmission of focused beams and plane waves, respectively), the measurement results indicate that these techniques are nearly equivalent. The peak systolic velocities measured in 22 healthy common carotid arteries by the two VD techniques were very close (according to Bland–Altman analysis, the average difference was 3.2%, with limits of agreement of ±8.6%). Application of Bland–Altman analysis to comparison of either VD technique with the spectral Doppler method provided a 21%–25% average difference with ±13%–15% limits of agreement. Analysis of the results obtained from 15 internal carotid arteries led to similar conclusions, indicating significant overestimation of peak systolic velocity with the spectral Doppler method. Inter- and intra-operator repeatability measurements performed in a group of 8 healthy volunteers provided equivalent results for all of the methods (coefficients of variability in the range 2.7%–6.9%), even though the sonographers were not familiar with the VD methods. The results of this study suggest that the introduction of vector Doppler methods in commercial machines may finally be considered mature and capable of overcoming the angle-dependent overestimation typical of the standard spectral Doppler approach.

Common Carotid Artery Peak-Systolic Velocity Ratio Predicts High-Grade Common Carotid Stenosis

Screening for common carotid artery (CCA) stenosis with duplex ultrasound (DUS) velocity criteria alone can be limited due to within-patient and between-patients hemodynamic variability. This study evaluated inter-CCA velocity ratio criteria to predict high-grade CCA stenosis. Retrospective review of consecutive patients who underwent computed tomography angiography (CTA) and DUS peak-systolic velocity (PSV) measurements of bilateral CCA, independently recorded, between 2008 and 2014. Patients with dampened CCA waveforms on DUS, readily indicating high-grade proximal stenosis, consistuted group B. The remainder without dampened waveforms constituted group A. Inter-CCA PSV ratios were calculated by dividing the higher CCA PSV to the lower one of the other side, so the ratios would always be >1. Ratios were subsequently paired with each respective unilateral CCA diameter stenosis (uDS) and differential bilateral CCA diameter stenosis (dDS). A quadratic regression model was fitted to predict uDS and dDS. Receiver operating characteristic curves were used to determine optimal ratios for ≥50% CCA stenosis. The study excluded patients with carotid artery occlusion. From 174 patients, 167 patients were included in group A and seven in group B. In group A, 31 patients had ≥50% uDS and 17 had ≥50% dDS. All stenoses ≥50% were identified on the same side with the higher PSV. Inter-CCA PSV ratio predicted ≥50% uDS (r2 = 0.57; P < .0001) and dDS (r2 = 0.75; P < .0001; Fig). In group B, all patients had ≥60% stenosis that involved the vessel origin. An increasing inter-CCA PSV ratio showed a trend toward contralateral high-grade stenosis (r2 = .54, P = .06). Receiver operating characteristic curves for ≥50% uDS showed an optimal threshold CCA ratio ≥1.96 with 93% accuracy, 75% sensitivity, and 97% specificity (area under curve, 0.857; 95% confidence interval, 0.755-0.958) and for ≥50% a dDS ratio ≥2.62 with 97% accuracy, 82% sensitivity, and 99% specificity (area under curve, 0.938; 95% confidence interval, 0.828-1.0). DUS-based CCA PSV ratio can accurately predict unilateral and differential high-grade CCA stenosis. Also, in patients with dampened waveforms, it implied contralateral severe proximal stenosis. This parameter should be further validated in prospective studies and is a promising adjunct screening tool to detect high-grade common carotid stenosis.

Lack of association between carotid artery stenosis and stroke or myocardial injury after noncardiac surgery in high-risk patients.

Whether carotid artery stenosis predicts stroke after noncardiac surgery remains unknown. We therefore tested the primary hypothesis that degree of carotid artery stenosis is associated with in-hospital stroke or 30-day all-cause mortality after noncardiac surgery. As carotid artery stenosis is also a marker for cardiovascular disease, our secondary hypothesis was that degree of carotid artery stenosis is associated with postoperative myocardial injury. We included adults who had noncardiac, noncarotid surgery at Cleveland Clinic from 2007 to 2011 and had carotid duplex ultrasound performed either within 6 months before or 1 month after surgery. Internal carotid artery peak systolic velocity (ICA PSV) was used as a measure of carotid artery stenosis severity. A multivariate (i.e., multiple outcomes per patient) generalized estimating equation model was used to assess the association between highest ICA PSV and the composite of stroke and 30-day mortality after adjusting for predefined potentially confounding variables. Of 2,110 patients included, 112 (5.3%) died within 30 days and 54 (2.6%) suffered postoperative in-hospital stroke. ICA PSV was not associated with this composite outcome (odds ratio of 1.0 [95% confidence interval: 0.99, 1.02] for a 10-unit increase, P = 0.55). ICA PSV was also not associated with postoperative myocardial injury (odds ratio 1.00 [0.99, 1.02], P = 0.49). This cohort represents a high-risk population, as carotid duplex examinations were likely prompted by neurological symptoms. There was nonetheless no association between carotid artery stenosis and perioperative stroke or 30-day mortality after noncardiac surgery.

CT Angiography–derived Duplex Ultrasound Velocity Criteria in Patients with Carotid Artery Stenosis

Validation of carotid duplex ultrasound velocity criteria (CDUS VC) to grade the severity of extracranial carotid artery stenosis has traditionally been based on conventional angiography measurements. In the last decade, computed tomographic angiography (CTA) has largely replaced conventional arch and carotid arteriography (CA) for diagnostic purposes. Given the low number of CA being performed, it is impractical to expect noninvasive vascular laboratories to be validated using this modality. CDUS VC have not been developed with the use of CTA-derived measurements. The objective was to determine optimal CDUS VC from CTA-derived measurements with the North American Symptomatic Carotid Endarterectomy Trial (NASCET) method for 50% and 80% stenosis. A retrospective review of all patients who underwent CDUS and CTA from 2000 to 2009 was performed. Vessel diameters were measured on CTA, and corresponding CDUS velocities were recorded. Percent stenosis was calculated using the NASCET method. Receiver operating characteristic (ROC) curves were generated for internal carotid artery (ICA) peak systolic velocity (PSV), ICA end diastolic velocity (EDV), and ICA PSV to common carotid artery PSV ratio (PSVR) for 50% and 80% stenosis. Velocity cut points were determined with equal weighting of sensitivity and specificity. A total of 575 vessels were analyzed to create the ROC curves. A 50% stenosis analysis yielded ideal cut points for PSV, EDV, and PSVR of 130cm/sec, 42cm/sec, and 1.75. An 80% stenosis analysis yielded ideal cut points for PSV, EDV, and PSVR of 297cm/sec, 84cm/sec, and 3.06. CTA-derived CDUS VC appeared to be reliable in defining 50% and 80% stenosis in patients with carotid artery stenosis. Although CDUS VC defined in this study were different from many of the previously published VC for the same percent stenosis, there were many similarities to those reported by the Society of Radiologists in Ultrasound consensus conference. We feel that CTA should be the gold standard imaging technique for validating CDUS VC.

Transcranial Doppler Investigation of Hemodynamic Alterations Associated With Blunt Cervical Vascular Injuries in Trauma Patients

Blunt cervical vascular injuries, often missed with current screening methods, have substantial morbidity and mortality, and there is a need for improved screening. Elucidation of cerebral hemodynamic alterations may facilitate serial bedside monitoring and improved management. Thus, the objective of this study was to define cerebral flow alterations associated with single blunt cervical vascular injuries using transcranial Doppler sonography and subsequent Doppler waveform analyses in a trauma population. In this prospective pilot study, patients with suspected blunt cervical vascular injuries had diagnoses by computed tomographic angiography and were examined using transcranial Doppler sonography to define cerebral hemodynamics. Multiple vessel injuries were excluded for this analysis, as the focus was to identify hemodynamic alterations from isolated injuries. The inverse damping factor characterized altered extracranial flow patterns; middle cerebral artery flow velocities, the pulsatility index, and their asymmetries characterized altered intracranial flow patterns. Twenty-three trauma patients were evaluated: 4 with single internal carotid artery injuries, 5 with single vertebral artery injuries, and 14 without blunt cervical vascular injuries. All internal carotid artery injuries showed a reduced inverse damping factor in the internal carotid artery and dampened ipsilateral mean flow and peak systolic velocities in the middle cerebral artery. Vertebral artery injuries produced asymmetry of a similar magnitude in the middle cerebral artery mean flow velocity with end-diastolic velocity alterations. These data indicate that extracranial and intracranial hemodynamic alterations occur with internal carotid artery and vertebral artery blunt cervical vascular injuries and can be quantified in the acute injury phase by transcranial Doppler indices. Further study is required to elucidate cerebral flow changes resulting from a single blunt cervical vascular injury, which may guide future management to preserve cerebral perfusion after trauma.

Agreement between site-reported and ultrasound core laboratory results for duplex ultrasound velocity measurements in the Carotid Revascularization Endarterectomy versus Stenting Trial

Patients in the Carotid Revascularization Endarterectomy vs Stenting Trial (CREST) had duplex ultrasound (DU) scans prior to treatment and during follow-up to document the severity of carotid disease and the anatomic outcome of carotid endarterectomy (CEA) or carotid artery stenting (CAS). An ultrasound core laboratory (UCL) reviewed DU data from the clinical sites. This analysis was done to determine the agreement between site-reported and UCL-verified DU velocity measurements. Clinical site DU worksheets, B-mode images, and Doppler velocity waveforms for the treated carotid arteries were reviewed at the UCL. The highest internal carotid artery peak systolic velocity (PSV) and associated Doppler angle were verified. If the angle was misaligned by >3 degrees, it was remeasured at the UCL and the PSV was recalculated. Agreement for PSV was defined as site-reported PSV within ± 5% of UCL-verified PSV. Transcription errors were corrected by the UCL but were not considered as disagreements. Follow-up analysis was limited to patients who received the assigned treatment. The UCL reviewed 1702 prior-to-treatment and 1743 12-month follow-up DU scans (873 CEA, 870 CAS) from 111 clinical sites. Site-reported and UCL-verified PSV agreed in 1124 (66%) of the prior-to-treatment scans and 1200 (69%) of the follow-up scans. In those cases with a disagreement, Doppler angle accounted for disagreement in 339 (59%) of the prior-to-treatment scans and 277 (51%) of the follow-up scans. Based on a threshold PSV for ≥ 70% stenosis of ≥ 230 cm/s on the prior-to-treatment scans and ≥ 300 cm/s on the follow-up scans, UCL review resulted in reclassification of stenosis severity in 75 (4.4%) of the prior-to-treatment scans and 13 (0.75%) of the follow-up scans. There is evidence that the proportion of reclassification at follow-up was greater for CAS (10 scans; 1.2%) than for CEA (three scans; 0.34%) (P = .057). There was a high rate of agreement between site-reported and UCL-verified DU results in CREST, and UCL review was associated with a low rate of stenosis reclassification. However, angle alignment errors were quite common and prompted recalculation of velocity in 20% of prior-to-treatment scans and 18% of follow-up scans. The use of a UCL provides a uniform process for DU interpretation and can identify sources of error and suggest technical improvements for future studies.

Establishing Common Carotid Artery Peak Systolic Velocity Ratio Criteria to Predict Common Carotid Stenosis

Establishing Common Carotid Artery Peak Systolic Velocity Ratio Criteria to Predict Common Carotid Stenosis

Carotid Stenosis: A Risk Factor for Cerebral White-matter Disease

We sought to study the association between carotid stenosis and white-matter hyperintensity (WMH) among patients without intracranial large-vessel stenosis. This was a prospective study of patients with acute lacunar infarcts without concomitant intracranial large-vessel stenosis having undergone carotid ultrasonography. WMH was quantified using the modified Fazekas scale. Patients were grouped into quartiles based on the degree of carotid stenosis. The association among carotid stenosis, vascular risk factors, and WMH were modeled using logistic regression analysis. In all, 100 patients with a mean age of 56.2± 11.7 years were studied. The quartile with the greatest carotid stenosis had a mean internal/common carotid artery peak systolic velocity ratio of 2.36. Total WMH was 4.64 in the highest quartile and 2.52 in the lowest quartile of carotid stenosis. Periventricular (pv)-WMH was significantly greater between the highest and lowest quartiles (2.80 versus 1.28, P = .025). No significant difference was observed for deep subcortical WMH (1.84 versus 1.24, P = .281). With increasing carotid stenosis, increase in both ipsilateral and contralateral pv-WMH was observed. When patients with significant carotid stenosis were compared to those without significant carotid stenosis, pv-WMH was significantly higher in the group with significant stenosis even after correcting for age and comorbid vascular risk factors (odds ratio 1.24; confidence interval 1.0-1.54). Carotid stenosis is an important risk factor for WMH. Volumes of pv-WMH significantly increase with higher grades of carotid stenosis.

Carotid Doppler Velocity Measurements and Anatomic Stenosis

Duplex ultrasound with Doppler velocimetry is widely used to evaluate the presence and severity of internal carotid artery stenosis; however, a variety of velocity criteria are currently being applied to classify stenosis severity. The purpose of this study is to compare published Doppler velocity measurements to the severity of internal carotid artery stenosis as assessed by x-ray angiography in order to clarify the relationship between these 2 widely used approaches to assess carotid artery disease. Scatter diagrams or "scattergrams" of correlations between Doppler velocity measurements and stenosis severity as assessed by x-ray contrast angiography were obtained from published articles for native and stented internal carotid arteries. The scattergrams were graphically digitized, combined, and segmented into categories bounded by 50% and 70% diameter reduction. These data were combined and divided into 3 sets representing different velocity parameters: (1) peak systolic velocity, (2) end-diastolic velocity, and (3) the internal carotid artery to common carotid artery peak systolic velocity ratio. The horizontal axis of each scattergram was transformed to form a cumulative distribution function, and thresholds were established for the stenosis categories to assess data variability. Nineteen publications with 22 data sets were identified and included in this analysis. Wide variability was apparent between all 3 velocity parameters and angiographic percent stenosis. The optimal peak systolic velocity thresholds for stenosis in stented carotid arteries were higher than those for native carotid arteries. Within each category of stenosis, the variability of all 3 velocity parameters was significantly lower in stented arteries than in native arteries. Although Doppler velocity criteria have been successfully used to classify the severity of stenosis in both native and stented carotid arteries, the relationship to angiographic stenosis contains significant variability. This analysis of published studies suggests that further refinements in Doppler velocity criteria will not lead to improved correlation with carotid stenosis as demonstrated by angiography.

589 Grading of a carotid bruit and its relationship to carotid artery peak systolic velocities

589 Grading of a carotid bruit and its relationship to carotid artery peak systolic velocities

Increased internal carotid artery peak systolic velocity is associated with presence of significant atherosclerotic plaque instability independent of degree of ICA stenosis

The aim of our work was to study the relationship between Doppler ultrasound velocity measurements and the presence of histologic features of plaque instability in carotid atherosclerosis, in particular, intraplaque hemorrhage (IPH). Consecutive patients undergoing carotid endarterectomy in a one-year period were included. All patients were examined by duplex ultrasonography and carotid angiography. Endarterectomy specimens were examined histologically for features of plaque instability. The quantity of IPH was measured by digital image analysis. The associations between Peak Systolic Velocity (PSV), end-diastolic velocity (EDV), degree of ICA stenosis, shape and length of the lesion and the features of plaque instability and quantity of IPH were assessed. Seventy-four patients (20 asymptomatic, 54 symptomatic) were included. PSV was independently associated with the presence of significant IPH [p < 0.001, OR = 1.04 (95% CI = 1.01–1.06)], as was the degree of angiographic ICA stenosis [p < 0.05, OR = 0.98 (95% CI = 0.92–1.6)]. Neither EDV nor the shape of the lesion was associated with IPH (p = 0.26 and p = 0.38, respectively). A close correlation was observed between PSV and the quantity of IPH (r2 = 0.68, p < 0.0001). A significant association was observed between PSV and the presence of plaque ulceration (p < 0.05); however, this was not found to be independent of the quantity of IPH and the degree of ICA stenosis [p = 0.17, OR = 1.28 (95% CI = 0.6–2.44)]. PSV at the site of ICA stenosis appears to be associated with the quantity of intraplaque hemorrhage, independent of the angiographic degree of ICA stenosis. We propose that the role of Doppler velocity measurements extends beyond measurement of the degree of ICA stenosis. Increased ICA peak systolic velocity by itself may be an indicator of atherosclerotic plaque instability.