Background: 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. Methods: 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. Results: 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. Conclusion: 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.
RushmerRFBakerDWStegallHF. Transcutaneous Doppler flow detection as a nondestructive technique. J Appl Physiol. 1966;21(2):554–566.
2.
BarberFEBakerDWNationAWStrandnessDEJrReidJM. Ultrasonic duplex echo-Doppler scanner. IEEE Trans Biomed Eng. 1974;21(2):109–113.
3.
BlackshearWMJrPhillipsDJThieleBL. Detection of carotid occlusive disease by ultrasonic imaging and pulsed Doppler spectrum analysis. Surgery. 1979;86(5):698–706.
4.
GrantEGBensonCBMonetaGL. Carotid artery stenosis: grayscale and Doppler ultrasound diagnosis—Society of Radiologists in Ultrasound consensus conference. Radiology. 2003;229(2):340–346. [also in] Ultrasound Q. 2003;19(4):190-198.
5.
GrantEGDuerinckxAJEl SadenSM. Ability to use duplex US to quantify internal carotid arterial stenoses: fact or fiction?Radiology. 2000;214(1):247–252.
6.
ComerotaAJSalles-CunhaSXDaoudYJonesLBeebeHG. Gender differences in blood velocities across carotid stenoses. J Vasc Surg. 2004;40(5):939–944.
7.
FillingerMFBakerRJJrZwolakRMMussonALenzJEMottJ. Carotid duplex criteria for a 60% or greater angiographic stenosis: variation according to equipment. J Vasc Surg. 1996;24(5):856–864.
AlexandrovAVBrodieDSMcLeanAHamiltonPMurphyJBurnsPN. Correlation of peak systolic velocity and angiographic measurement of carotid stenosis revisited. Stroke. 1997;28(2):339–342.
10.
EliasziwMRankinRNFoxAJHaynesRBBarnettHJ. Accuracy and prognostic consequences of ultrasonography in identifying severe carotid artery stenosis. North American Symptomatic Carotid Endarterectomy Trial (NASCET) Group. Stroke. 1995;26(10):1747–1752.
11.
HathoutGMFinkJREl-SadenSMGrantEG. Sonographic NASCET index: a new Doppler parameter for assessment of internal carotid artery stenosis. AJNR Am J Neuroradiol. 2005;26(1):68–75.
12.
Heijenbrok-KalMHNederkoornPJBuskensEvan der GraafYHuninkMG. Diagnostic performance of duplex ultrasound in patients suspected of carotid artery disease: the ipsilateral versus contralateral artery. Stroke. 2005;36(10):2105–2109.
13.
Heijenbrok-KalMHBuskensENederkoornPJvan der GraafYHuninkMG. Optimal peak systolic velocity threshold at duplex us for determining the need for carotid endarterectomy: a decision analytic approach. Radiology. 2006;238(2):480–488.
14.
MonetaGLTaylorDCZierlerREKazmersABeachKStrandnessDEJr. Asymptomatic high-grade internal carotid artery stenosis: is stratification according to risk factors or duplex spectral analysis possible?J Vasc Surg. 1989;10(5):475–482.
15.
MonetaGLEdwardsJMPapanicolaouG. Screening for asymptomatic internal carotid artery stenosis: duplex criteria for discriminating 60% to 99% stenosis. J Vasc Surg. 1995;21(6):989–994.
16.
NeschisDGLexaFJDavisJTCarpenterJP. Duplex criteria for determination of 50% or greater carotid stenosis. J Ultrasound Med. 2001;20(3):207–215.
17.
SchwartzSWChamblessLEBakerWHBroderickJPHowardG. Consistency of Doppler parameters in predicting arteriographically confirmed carotid stenosis. Asymptomatic Carotid Atherosclerosis Study Investigators. Stroke. 1997;28(2):343–347.
18.
ShakhnovichIKiserDSatianiB. Importance of validation of accuracy of duplex ultrasonography in identifying moderate and severe carotid artery stenosis. Vasc Endovascular Surg. 2010;44(6):483–488.
19.
ChahwanSMillerMTPigottJPWhalenRCJonesLComerotaAJ. Carotid artery velocity characteristics after carotid artery angioplasty and stenting. J Vasc Surg. 2007;45(3):523–526.
20.
LalBKHobsonRW2ndGoldsteinJChakhtouraEYDuránWN. Carotid artery stenting: is there a need to revise ultrasound velocity criteria?J Vasc Surg. 2004;39(1):58–66.
21.
LalBKHobsonRW2ndTofighiBKapadiaICuadraSJamilZ. Duplex ultrasound velocity criteria for the stented carotid artery. J Vasc Surg. 2008;47(1):63–73.
22.
RingerAJGermanJWGutermanLRHopkinsLN.Follow-up of stented carotid arteries by Doppler ultrasound. Neurosurgery. 2002;51(3):639–643; discussion 643.
23.
RobbinMLLockhartMEWeberTM. Carotid artery stents: early and intermediate follow-up with Doppler US. Radiology. 1997;205(3):749–756.
StanzialeSFWholeyMHBoulesTNSelzerFMakarounMS. Determining in-stent stenosis of carotid arteries by duplex ultrasound criteria. J Endovasc Ther. 2005;12(3):346–353.
26.
MeenanRTSahaSChouR. Effectiveness and Cost-Effectiveness of Echocardiography and Carotid Imaging in the Management of Stroke. Evidence Report/Technology Assessment Number 49. (Prepared by Oregon Health & Science University Evidence-based Practice Center under Contract No. 290-97-0018.) AHRQ Publication No. 02-EO22. Rockville, MD: Agency for Healthcare Research and Quality.
HadlockJBeachKW; D.EStrandness Vascular Laboratory SonographersVelocity variability in ultrasonic Doppler examinations. Ultrasound Med Biol. 2009;35(6):949–954.
29.
BeachKWBergelinROLeottaDF. Standardized ultrasound evaluation of carotid stenosis for clinical trials: University of Washington Ultrasound Reading Center. Cardiovasc Ultrasound. 2010;8:39.
30.
BreslauPJKnoxRFellGGreeneFMThieleBLStrandnessDEJr. Effect of carbon dioxide on flow patterns in normal extracranial arteries. J Surg Res. 1982;32(2):97–103.
31.
CameronOGModellJGHariharanM. Caffeine and human cerebral blood flow: a positron emission tomography study. Life Sci. 1990;47(13):1141–1146.
32.
MintunMAVlassenkoAGRundleMMRaichleME.Increased lactate/pyruvate ratio augments blood flow in physiologically activated human brain. Proc Natl Acad Sci U S A. 2004;101(2):659–664..
33.
DagerSRLaytonMEStraussW. Human brain metabolic response to caffeine and the effects of tolerance. Am J Psychiatry. 1999;156(2):229–237.
34.
BoyajianRAOtisSM. Acute effects of smoking on human cerebral blood flow: a transcranial Doppler ultrasonography study. J Neuroimaging. 2000;10(4):204–208.
35.
CuffeRLRothwellPM. Effect of nonoptimal imaging on the relationship between the measured degree of symptomatic carotid stenosis and risk of ischemic stroke. Stroke. 2006;37(7):1785–1791.
HermelingEHoeksAPWinkensMH. Noninvasive assessment of arterial stiffness should discriminate between systolic and diastolic pressure ranges. Hypertension. 2010;55(1):124–130.
38.
BeachKW.Principles of ultrasonic imaging and instrumentation, Figure 5.23. In: ANNicolaidesKWBeachKyriacouEPattichisCS, eds. Atherosclerosis—Ultrasound and Carotid Bifurcation. Springer-Verlag; 2012.
39.
BarnettHJTaylorDWEliasziwM. Benefit of carotid endarterectomy in patients with symptomatic moderate or severe stenosis. North American Symptomatic Carotid Endarterectomy Trial Collaborators. N Engl J Med. 1998;339(20):1415–1425.
40.
GalisZSSukhovaGKLarkMWLibbyP. Increased expression of matrix metalloproteinases and matrix degrading activity in vulnerable regions of human atherosclerotic plaques. J Clin Invest. 1994;94(6):2493–2503.
41.
GrønholdtMLNordestgaardBGWiebeBMWilhjelmJESillesenH. Echo-lucency of computerized ultrasound images of carotid atherosclerotic plaques are associated with increased levels of triglyceride-rich lipoproteins as well as increased plaque lipid content. Circulation. 1998;97(1):34–40.
42.
de BoerOJvan der WalACTeelingPBeckerAE. Leucocyte recruitment in rupture prone regions of lipid-rich plaques: a prominent role for neovascularization?Cardiovasc Res. 1999;41(2):443–449.
43.
BeachKWHatsukamiTDetmerPR. Carotid artery intraplaque hemorrhage and stenotic velocity. Stroke. 1993;24(2):314–319.
44.
MeairsSHennericiM. Four-dimensional ultrasonographic characterization of plaque surface motion in patients with symptomatic and asymptomatic carotid artery stenosis. Stroke. 1999;30(9):1807–1813.
45.
TrivediRAU-King-ImJMGravesMJ. MRI-derived measurements of fibrous-cap and lipid-core thickness: the potential for identifying vulnerable carotid plaques in vivo. Neuroradiology. 2004;46(9):738–743.
46.
LiZYHowarthSPTangTGillardJH. How critical is fibrous cap thickness to carotid plaque stability? A flow-plaque interaction model. Stroke. 2006;37(5):1195–1199.
47.
KingAShipleyMMarkusH; for the ACES Investigators. Optimizing protocols for risk prediction in asymptomatic carotid stenosis using embolic signal detection: The Asymptomatic Carotid Emboli Study. Stroke. 2011;42(10):2819–2824.
