Critical appraisal of the Carotid Duplex Consensus criteria in the diagnosis of carotid artery stenosis.

Abstract

Clinicians have relied on published institutional experience for interpreting carotid duplex ultrasound studies (CDUS). This study will validate the ultrasound imaging consensus criteria published in 2003.
The CDUS and angiography results of 376 carotid arteries were analyzed. Receiver-operating characteristic (ROCs) curves were used to compare peak systolic velocities (PSVs), end-diastolic velocities (EDVs) of the internal carotid artery (ICA), and ICA/common carotid (CCA) ratios in detecting < 50%, 50% to 69% (ICA PSV of 125-230 cm/s), and 70% to 99% (PSV of ≥ 230 cm/s) stenosis according to the consensus criteria.
The consensus criteria uses a PSV of 125 to 230 cm/s for detecting angiographic stenosis of 50% to 69%, which has a sensitivity of 93%, specificity of 68%, and overall accuracy of 85%. A PSV of ≥ 230 cm/s for ≥ 70% stenosis had a sensitivity of 99%, specificity of 86%, and overall accuracy of 95%. ROC curves showed that the ICA PSV was significantly better (area under the curve [AUC], 0.97) than EDV (AUC, 0.94) or ICA/CCA ratio (AUC, 0.84; P = .036) in detecting ≥ 70% stenosis and ≥ 50% stenosis. Pearson correlations showed a statistical difference between the correlation of PSV with angiography (0.833; 95% confidence interval [CI], 0.8-0.86), EDV with angiography (0.755; 95% CI, 0.71-0.80), and ICA/CCA systolic ratio with angiography (0.601; 95% CI, 0.53-0.66; P < .0001) in detecting 70% to 99% stenosis. Adding the EDV values or the ratios to the PSV values did not improve accuracy. The consensus criteria for diagnosing 50% to 69% stenosis can be significantly improved by using an ICA PSV of 140 to 230 cm/s, with a sensitivity of 94%, specificity of 92%, and overall accuracy of 92%.
The consensus criteria can be accurately used for diagnosing ≥ 70% stenosis; however, the accuracy can be improved for detecting 50% to 69% stenosis if the ICA PSV is changed to 140 to < 230 cm/s.

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From the Society for Vascular Surgery
Critical appraisal of the Carotid Duplex Consensus
criteria in the diagnosis of carotid artery stenosis
Ali F. AbuRahma, MD,aMohit Srivastava, MD,aPatrick A. Stone, MD,aAlbeir Y. Mousa, MD,a
Akhilesh Jain, MD,aL. Scott Dean, PhD, MBA,bTammi Keiffer, RN,band Mary Emmett, PhD,b
Charleston, WV
Background: Clinicians have relied on published institutional experience for interpreting carotid duplex ultrasound
studies (CDUS). This study will validate the ultrasound imaging consensus criteria published in 2003.
Methods: The CDUS and angiography results of 376 carotid arteries were analyzed. Receiver-operating characteristic
(ROCs) curves were used to compare peak systolic velocities (PSVs), end-diastolic velocities (EDVs) of the internal
carotid artery (ICA), and ICA/common carotid (CCA) ratios in detecting <50%, 50% to 69% (ICA PSV of 125-230
cm/s), and 70% to 99% (PSV of >230 cm/s) stenosis according to the consensus criteria.
Results: The consensus criteria uses a PSV of 125 to 230 cm/s for detecting angiographic stenosis of 50% to 69%, which
has a sensitivity of 93%, specificity of 68%, and overall accuracy of 85%. A PSV of >230 cm/s for >70% stenosis had a
sensitivity of 99%, specificity of 86%, and overall accuracy of 95%. ROC curves showed that the ICA PSV was significantly
better(areaunderthecurve[AUC],0.97)thanEDV(AUC,0.94)orICA/CCAratio(AUC,0.84; P?.036)indetecting
>70% stenosis and >50% stenosis. Pearson correlations showed a statistical difference between the correlation of PSV
with angiography (0.833; 95% confidence interval [CI], 0.8-0.86), EDV with angiography (0.755; 95% CI, 0.71-0.80),
and ICA/CCA systolic ratio with angiography (0.601; 95% CI, 0.53-0.66; P < .0001) in detecting 70% to 99% stenosis.
Adding the EDV values or the ratios to the PSV values did not improve accuracy. The consensus criteria for diagnosing
50% to 69% stenosis can be significantly improved by using an ICA PSV of 140 to 230 cm/s, with a sensitivity of 94%,
specificity of 92%, and overall accuracy of 92%.
Conclusions: The consensus criteria can be accurately used for diagnosing >70% stenosis; however, the accuracy can be
improved for detecting 50% to 69% stenosis if the ICA PSV is changed to 140 to <230 cm/s. (J Vasc Surg 2011;53:
53-60.)
Color duplex ultrasound imaging has become the
method of choice for the noninvasive evaluation of ex-
tracranial carotid artery disease.1,2The degree of carotid
artery stenosis is largely based on an analysis of the peak
systolic velocity (PSV) or the end-diastolic velocity (EDV),
or both, of the carotid artery. The performance and inter-
pretation of carotid duplex ultrasound results vary consid-
erably from one vascular laboratory to another.2-4This,
along with increasing reports advocating carotid endarter-
ectomy (CEA) based on carotid duplex results alone, with-
out preoperative arteriography,1,5,6makes it imperative to
verify that the measurements of stenosis derived from the
duplex ultrasound studies are as accurate as possible.
Accreditation of noninvasive vascular laboratories, in
general, has resulted in an increased degree of standardiza-
tion of carotid duplex ultrasound examinations; however, a
wide range of practice patterns still exists. Clinicians have
relied on published institutional experience for interpreting
carotid duplex ultrasound studies at their institutions. Be-
cause of this, a panel of experts from several medical spe-
cialties convened in October 2002 in San Francisco, Cali-
fornia, under the auspices of the Society of Radiologists in
Ultrasound, to arrive at a consensus regarding the perfor-
mance of Doppler ultrasound imaging to aid in the diag-
nosis of internal carotid artery (ICA) stenosis. This panel of
experts recommended a cutoff PSV of the ICA of ?125
cm/s and ?230 cm/s for predicting angiographic ?50%
stenosis and ?70% ICA stenosis, respectively.2It should be
noted that the recommended criteria in the Society of
Radiologists in Ultrasound report are based on an analysis
of several published studies and the experience of the
panelists, and they are not a validated criteria.
Thepurposeofthisstudywastovalidatetheultrasound
consensus criteria, published in 2003, used to diagnose
various severities of carotid stenosis and to analyze its
application at our institution. To our knowledge, only one
previousreporthasspecificallyanalyzedthecarotidconsen-
sus criteria for the diagnosis of ?70% carotid stenosis.4
METHODS
This study was approved by the Institutional Review
Board of Charleston Area Medical Center/West Virginia
University, Charleston Division.
Patient population. We analyzed 376 arteries in 197
patients (179 patients with bilateral carotid studies and 18
patients with unilateral carotid studies) who underwent
From the Department of Surgery, Robert C. Byrd Health Sciences Center,
West Virginia University;aand Charleston Area Medical Center.b
Competition of interest: none.
Presented at the 2010 Vascular Annual Meeting, Boston, Mass, June 10-13,
2010.
Correspondence:AliF.AbuRahma,MD,DepartmentofSurgery,RobertC.
Byrd Health Sciences Center, West Virginia University, 3110 MacCorkle
Ave, SE, Charleston, WV 25304 (e-mail: ali.aburahma@camc.org).
The editors and reviewers of this article have no relevant financial relationships
to disclose per the JVS policy that requires reviewers to decline review of any
manuscript for which they may have a competition of interest.
0741-5214/$36.00
Copyright © 2011 by the Society for Vascular Surgery.
doi:10.1016/j.jvs.2010.07.045
53

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carotidcolorduplexultrasoundscanningandarteriography
during a 3-year period. Patients were identified from the
angiography procedure log, which was searched using the
angiography information system, and a list of patients was
generated consisting of patients who underwent carotid
angiography. This patient list was cross-referenced with the
vascular laboratory report archive, which allowed identifi-
cation of all patients who had carotid duplex ultrasound
imagingandangiography?30daysoftheduplexscanning.
Indications for carotid duplex ultrasound scanning in-
cluded hemispheric transient ischemic attacks (TIAs),
hemispheric stroke symptoms, nonhemispheric TIAs, and
asymptomatic carotid bruits. Carotid angiography was per-
formed for patients with ?50% symptomatic carotid steno-
sis, ?70% asymptomatic carotid stenosis, and for patients
with an interpretation discrepancy between the carotid
duplex ultrasound study and other imaging modalities
(magnetic resonance angiography or computed tomogra-
phy angiography).
Carotid color duplex ultrasound imaging was per-
formed using an ATL 5000 instrument (Phillips, Bothell,
Wash) using a 7- to 4-MHz linear transducer. The com-
mon carotid artery (CCA), external carotid artery, and
ICAs were identified, and images were taken. Every effort
was made to maintain a Doppler angle of incidence at 60°.
Doppler waveforms were obtained along the course of
these vessels. PSVs and EDVs were recorded in the CCA,
ICA, and external carotid arteries. The ICA/CCA PSV
ratio was calculated by dividing the PSV of the ICA, which
was selected for analysis by the PSV of the CCA. Specific
recordings were also taken proximal to the stenosis, at the
stenosis site, and immediately distal to the stenosis in the
ICA, as seen on real-time imaging. All duplex scans were
interpreted by a single investigator (a board-certified vas-
cularsurgeon,RPVI)blindedtothearteriographicfindings
and confirmed by another investigator who is also a board-
certified vascular surgeon with the RPVI credential.
Arteriographic evaluation was performed using selec-
tive intra-arterial digital subtraction, four-vessel arch aor-
tography, and carotid arteriography. These were also per-
formed by several board-certified vascular surgeons and a
vascular interventionalist. The point of maximal stenosis
was measured using calipers and then divided by the diam-
eter of the normal distal ICA to calculate the presence of
stenosis, according to the North American Symptomatic
Carotid Endarterectomy Trial (NASCET).7
The unit of analysis in this study was each individual
artery. The data used for analysis included the PSV and the
EDV of the ICA, the ICA/CCA PSV ratio, and the ICA/
CCAEDVratio.Thefollowingarterieswereexcludedfrom
the final analysis: previous CEA or carotid artery stenting,
carotid artery dissection, total carotid artery occlusion,
fibromuscular dysplasia, carotid artery distal to significant
brachiocephalic stenosis, and patients with inconclusive
carotid duplex ultrasound images.
Because the purpose of this study was to validate the
consensus panel criteria,2the following is a summary of
these criteria:
Primary parameters
● Normal carotid—an ICA PSV of ?125 cm/s with no
visible plaques
● ?50% stenosis—an ICA PSV of ?125 cm/s with
visible plaque of ?50% diameter reduction
● 50%to69%stenosis—anICAPSVrangeof125to230
cm/s with a visible plaque estimate of ?50% diameter
reduction
● ?70 stenosis but less than near occlusion—an ICA
PSV of ?230 cm/s and a plaque estimate of ?50%
diameter reduction
● Near occlusion—high, low, or undetectable PSVs
with visible plaques, variable systolic ratio
● Total occlusion—undetectable flow with visible
plaque, no detectable lumen
Other parameters recommended for use only in
borderline data
● Normal carotid—an ICA/CCA PSV ratio of ?2 and
an ICA EDV of ?40 cm/s
● ?50 carotid stenosis—an ICA/CCA ratio of ?2 and
an ICA EDV of ?40 cm/s
● 50% to 69% stenosis—an ICA/CCA PSV ratio of 2 to
4 and an ICA EDV of 40 to 100 cm/s
● ?70% stenosis to near occlusion—an ICA/CCA ratio
of ?4 and an ICA EDV of ?100 cm/s
We also analyzed the performance of our previously
published standard criteria.1The following is a summary of
these criteria:
● Normal carotid—an ICA PSV ?120 cm/s
● ?50carotidstenosis—anICAPSV?120to139cm/s
● ?50% stenosis—an ICA PSV of ?140 cm/s
● ?70% stenosis—ICA PSV of ?150 and EDV of ?90
cm/s
Statistical analysis. The data analysis was performed
using SAS 9.2 (SAS Institute Cary, NC) and Sigmaplot 10
software (Systat Software Inc, San Joe, Calif). A complete
descriptive analysis of all available variables was performed.
Receiver-operating characteristic (ROC) curve analyses
were used to compare angiographic stenosis with PSV,
EDV, systolic ratios, and diastolic ratios to establish opti-
mal criteria for determining significant stenosis. The
method of DeLong et al8was used to compare ROC areas
for the paired data. The difference of each area pair, its
standard error, and the 95% confidence interval (CI) were
computed. This was followed by the ?2statistic for the area
comparison and its associated P value. Additional statistical
analyses included Pearson correlations among PSV, EDV,
systolic ratios, and diastolic ratios with angiographic
stenosis.
RESULTS
This study includes 376 carotid arteries in 197 patients
(95 men, 102 women), with a mean age of 67.5 years
(range, 23-90 years). There were 43 (11.4%) normal ca-
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January 2011
54 AbuRahma et al

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rotid arteries, 113 (30%) with ?50% stenosis, 86 (22.9%)
with 50% to 69% stenosis, 97 (25.8%) with 70% to 99%
stenosis, and 37 (9.8%) with total occlusion based on
angiography.Duplexultrasoundimagingdetected36of37
carotid occlusions. The remaining 339 carotids were fur-
theranalyzedaccordingtotheirPSV,EDV,andICA/CCA
PSV ratio. Of 97 arteries with 70% to 99% stenosis on
angiography, 94 were detected on duplex ultrasound im-
aging; however, in three others with 99% stenosis (near
occlusion on angiography), two were felt to have ?50%
stenosis (PSVs were ?125 cm/s), and one had 50% to 69%
stenosis (PSV of ?230 cm/s).
Fifty-three percent of patients had hemispheric TIA
symptoms/stroke, and 47% had nonhemispheric TIA
symptoms or asymptomatic carotid bruits, or both. Forty-
four percent of patients were diabetics, 88% had hyperten-
sion, 78% had hypercholesterolemia, 34% were current
smokers, 55% were past smokers, and 72% had coronary
artery disease.
Table I reports the validation of the consensus criteria
for the diagnosis of normal carotid arteries and various
severities of carotid stenosis. The sensitivity, specificity, and
overall accuracy for the diagnosis of normal carotid arteries
and ?50% stenosis were reasonably good. However, the
sensitivityforthediagnosisof50%to69%stenosiswas93%,
with a specificity of 68% and an overall accuracy of 85%; and
for the diagnosis of ?70% to 99% stenosis, the sensitivity
was 99%, with a specificity of 86%, and an overall accuracy
of 95%.
Table II summarizes the Pearson overall correlation
of the consensus criteria to angiographic stenosis and the
correlation to 70% to 99% stenosis. As seen in this Table,
which shows the four variables considered in the consen-
sus criteria (ICA PSV, ICA EDV, ICA/CCA systolic
ratio, and the ICA/CCA diastolic ratio), the PSV has the
best overall correlation to angiography (0.813) and also
the best correlation for the diagnosis of 70% to 99%
stenosis (0.833).
When applying the ? statistic and using the PSV cutoff
as defined by the consensus criteria and compared with
angiography, the simple ? was 0.6870 (95% CI, 0.623-
0.750),withaweighted?of0.758(95%CI,0.705-0.810).
This is in contrast to a simple ? of 0.535 (95% CI, 0.461-
0.609), with a weighted ? 0.630 (95% CI, 0.565-0.695)
when using the EDV cutoff value.
Table III summarizes various PSVs, EDVs, systolic
ratios, and diastolic ratios as a single parameter or in com-
bination for detecting ?70% to 99% stenosis. As noted in
this Table, a PSV of ?230 cm/s was the most sensitive in
diagnosing ?70% to 99% stenosis. It should also be noted
thataPSV?280cm/shadabetterpositivepredictivevalue
(PPV) of 97% and an overall accuracy of 95%; however, the
sensitivity was down to 95% and the negative predictive
value (NPV) was 89%. When the PSV was ?230 with an
EDV ?100 or systolic ratio ?4, the sensitivity was 91%
withaspecificityof97%;however,thePPVwas99%andthe
NPV was 78%, with an overall accuracy of 93%.
TableIVsummarizestheICAPSVandEDVcutoffsfor
the diagnosis of ?50% and ?70% to 99% stenosis. As
noted, if the PSV was increased from ?125 cm/s (as
proposed by the consensus criteria) to ?140 cm/s, the
sensitivity in detecting ?50% stenosis would decrease from
97% to 94%; however, the specificity would improve from
85% to 91% and the overall accuracy from 89% to 92%.
Similarly, if the cutoff were changed to ?137 cm/s, the
sensitivity would be 96%, with a specificity of 91%, and an
overall accuracy of 93%. As also noted, when using the 230
cm/s cutoff for detecting ?70% to 99% stenosis, as recom-
mended by the consensus criteria, the sensitivity was 99%,
the specificity was 86%, and the overall accuracy was 94%. A
PSV of 252 cm/s had a sensitivity of 97%, specificity of
91%, and overall accuracy of 95%.
ROC analysis. Figs 1 to 3 are ROC curves plotting
sensitivity against specificity for diagnosing normal carotid
arteries, ?50% stenosis, and ?70% to 99% stenosis, respec-
tively. As noted in these Figures, the PSV was statistically
significantly better than EDVs and ICA/CCA systolic or
diastolic ratios in diagnosing normal carotid arteries or
?50% and ?70% stenosis. The area under the curve (AUC)
Table I. Validation of consensus criteria for duplex ultrasound vs angiographic stenosis
Consensus
Sensitivity
(95% CI)
Specificity
(95% CI)
PPVNPV
(95% CI)
Overall accuracy
(95% CI)(95% CI)
Stenosis
Normal
?50%
50%-69%
?70%
100 (100-100)
88 (83.6-91.7)
93 (89.3-96.1)
99 (97.7-100)
100 (100-100)
99 (95.6-100)
68 (58.5-76.9)
86 (80-92.8)
100 (100-100)
100 (98.7-100)
86 (82-90.8)
93 (89.9-96.5)
100 (100-100)
68 (58.8-77.3)
81 (72.2-89.2)
98 (95.1-100)
100 (100-100)
90 (84-95.9)
85 (77.2-92.6)
95 (90.2-99.1)
CI, Confidence interval; NPV, negative predictive value; PPV, positive predictive value.
Table II. Pearson correlation of the consensus criteria
for peak systolic velocity, end-diastolic velocity, systolic
ratio, and diastolic ratio to angiography
Duplex variable
Overall correlation
(95% CI)
Correlation to
?70%-99% stenosis
(95% CI)
Peak systolic velocity
End diastolic velocity
Systolic ratio
Diastolic ratio
0.81 (0.77-0.85)
0.7 (0.64-0.75)
0.57 (0.49-0.63)
0.54 (0.46-0.61)
0.833 (0.8-0.86)
0.755 (0.71-0.80)
0.601 (0.53-0.66)
0.60 (0.53-0.66)
CI, Confidence interval.
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for PSV, EDV, and systolic ratios for normal carotids were
0.92, 0.80, and 0.78, respectively (P ? .0001). The AUC
for PSV, EDV, and systolic ratios for ?50% stenosis were
0.97, 0.88, and 0.84 (P ? .0001). The AUC for PSV,
EDV,andsystolicratiosfor?70%stenosiswere0.97,0.94,
and 0.84 (P ? .0363).
Table V summarizes the performance of our present
standard criteria, which we published previously.1As
noted, the sensitivity, specificity, and overall accuracy for
detecting 50% to 69% stenosis were 96%, 82%, and 92%,
respectively.Thesensitivity,specificity,andoverallaccuracy
for the diagnosis of ?70% to 99% stenosis were 99%, 96%,
and98%,respectively.Ourstandardcriteriaweresomewhat
better than the consensus criteria, specifically for detecting
50% to 69% stenosis.
DISCUSSION
The most common parameters used to describe the
percentage of carotid artery stenosis are the PSV, EDV,
ICA/CCA PSV ratio, and the description of the plaque
itself.1,2,4,7In 1997, we published our standard criteria to
define stenosis based on these variables. We correlated
PSVs and EDVs to the angiographic findings. For the
diagnosisof?50%stenosis,whichwasthecutoffvalueused
in the NASCET for symptomatic patients, a PSV ?140
cm/s of the ICA had a very high sensitivity, specificity, and
PPV. A PSV of ?150 cm/s with an EDV ?90 cm/s was
very accurate in detecting ?70% to 99% stenosis.1
Several other classification systems have been used,
offering different carotid velocity threshold numbers to
define carotid stenosis2,3,9-15; however, no standardized
Table III. Summary of various velocities and ratios for detecting ?70-99% stenosis
Variable
Sensitivity
(95% CI)
Specificity
(95% CI)
PPV NPV
(95% CI)
Overall accuracy
(95% CI)(95% CI)
PSV ?230
PSV ?240
PSV ?280
Systolic ratio ?2.75
Systolic ratio ?3
Diastolic ratio ?3
Diastolic ratio ?3.5
PSV ?230 and EDV ?50
PSV ?230 and/or EDV ?90
PSV ?220 and diastolic ratio ?2.5
PSV ?230 and/or diastolic ratio ?5.5
PSV ?220 and systolic ratio ?2.5
PSV ?230 and/or systolic ratio ?4.5
EDV ?50 and systolic ratio ?2.5
EDV ?70 and/or systolic ratio ?4
EDV ?100 and/or systolic ratio ?4
PSV ?230 and EDV ?100 or systolic
ratio ?4
SR ?2 and DR ?3.5
SR ?3.5 and/or diastolic ratio ?3
99 (97-100)
97 (95-99.4)
95 (92.3-97.9)
87 (82.8-91.3)
86 (81.3-90)
87 (82.6-91.2)
86 (81.9-90.5)
97 (95.0-99.4)
99 (97-100)
88 (84.2-92.4)
99 (97-100)
89 (84.8-92.8)
99 (96.9-100)
88 (84.3-92.4)
97 (94.2-99.1)
91 (87.6-94.8)
86 (79.8-92.7)
87 (80.2-93.2)
93 (88.4-98.5)
85 (76.6-92.6)
91 (84.2-97.9)
80 (71.9-89.1)
89 (81.4-96.1)
88 (82.2-94.6)
86 (79.8-92.7)
87 (80-94.7)
86 (79.8-92.7)
91 (84.5-97.3)
85 (78.9-92)
88 (81.4-95.6)
83 (76.3-90.4)
96 (92-100)
93 (89.9-96.5)
94 (90.5-96.9)
97 (95.1-99.4)
95 (91.6-97.6)
97 (95.1-99.4)
93 (89.3-96.2)
96 (93.9-98.8)
95 (91.6-97.6)
93 (89.9-96.5)
95 (92.7-98.2)
93 (89.9-96.5)
97 (94.5-99.1)
93 (89.3-96.2)
96 (93.3-98.5)
92 (88.3-95.5)
99 (97-100)
97 (93.5-100)
94 (89.0-98.6)
89 (82.4-95)
68 (58.8-77.3)
63 (53.3-72.5)
68 (58.8-77.3)
65 (55.5-74.4)
94 (89-98.6)
97 (93.5-100)
71 (62.1-80.2)
97 (93.5-100)
72 (63.3-81.1)
97 (93.5-100)
71 (62.1-80.2)
93 (87.6-97.9)
78 (70-86.6)
94 (89.7-98.9)
94 (88.9-98.5)
95 (90.2-99.1)
86 (79.7-93.3)
87 (80.1-93.5)
85 (78.2-92.3)
87 (80.1-93.5)
94 (89.7-98.9)
94 (89.7-98.9)
88 (81.6-94.5)
94 (89.7-98.9)
89 (83.2-95.5)
94 (89.3-98.7)
88 (82-94.8)
92 (86.8-97.5)
92 (87.2-97.7)
91 (87.7-94.8)
86 (81.6-90.3)
87 (83.2-91.7)
97 (93.9-100)
90 (82.7-97)
78 (69.5-86.8)
99 (97.9-100)
97 (94.5-99.1)
91 (87.7-95.1)
78 (70.2-86.6)
64 (54.4-73.5)
70 (61-79.2)
93 (87.6-97.9)
87 (80.1-93.5)
85 (77.8-92)
CI, Confidence interval; EDV, end-diastolic velocity; NPV, negative predictive value; PPV, positive predictive value; PSV, peak systolic velocity.
Table IV. Sensitivity, specificity, and overall accuracy for velocity cutoffs for the diagnosis of ?50% and 70% to 99%
stenosis
Variable
Sensitivity
(95% CI)
Specificity
(95% CI)
PPVNPV
(95% CI)
Overall accuracy
(95% CI)(95% CI)
?50% stenosis
PSV ?125
PSV ?140
PSV ?150
PSV >137
?70-99% stenosis
PSV ?230
PSV ?240
PSV >252
PSV ?280
EDV ?70
EDV >87
97 (94.2-100)
94 (89.7-98)
85 (79.7-91)
96 (92.6-99.4)
85 (79.8-89.6)
91 (87.5-95.5)
94 (90.5-97.6)
91 (86.6-94.8)
77 (69.8-83.9)
88 (83.1-93.8)
93 (88.4-97.1)
87 (81.3-92.6)
98 (96.5-100)
96 (92.5-98.6)
88 (83-92.6)
97 (94.8-99.6)
89 (84.4-93.6)
92 (88.6-96.3)
90 (85.5-94.3)
93 (89-96.6)
99 (97-100)
97 (95-99.4)
97 (95.1-99.4)
95 (92.3-97.9)
96 (93.1-98.5)
93 (89.9-96.4)
86 (79.8-92.7)
87 (80.2-93.2)
91 (85.4-96.6)
93 (88.4-98.5)
85 (77.7-91.6)
95 (90.8-99.8)
93 (89.9-96.5)
94 (90.5-96.9)
96 (93.3-98.5)
97 (95.1-99.4)
93 (89.3-96.2)
98 (96.4-100)
98 (93.5-100)
94 (89-98.6)
94 (89-98.6)
89 (82.4-95)
91 (85-96.5)
84 (76.1-90.9)
94 (89.7-98.9)
94 (88.9-98.5)
95 (91.1-99.5)
95 (90.2-99.1)
92 (86.8-97.5)
94 (88.9-98.5)
CI, Confidence interval; EDV, end-diastolic velocity; NPV, negative predictive value; PPV, positive predictive value; PSV, peak systolic velocity.
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systemhadbeenestablisheduntil2002,2whentheCarotid
Consensus Criteria was developed by a panel of experts in
the fields of both radiology and vascular surgery. The panel
attempted to review all pertinent articles regarding criteria
for defining carotid stenosis to derive a standardized sys-
tem.2The difficulty is that there is no uniformity in inter-
pretation criteria, and different vascular laboratories may
report different results for similar Doppler velocity values.
Therefore, the objective of the consensus panel was to
achieve consistency and provide one system to delineate
carotid artery stenosis. It is to be noted that the consensus
criteriawerenotvalidatedandoneofitspurposesistoserve
as a starting point for vascular laboratories that have not
validated their own criteria. Therefore, internal validation
of carotid duplex interpretation criteria is essential.
The consensus panel recommended that the PSV
should be the primary parameter in assessing the percent-
age of carotid stenosis because it is reproducible and has
been found to have high rates of sensitivity, specificity, and
PPVs across most studies. They determined that a PSV of
?125 to 230 cm/s was consistent with ?50% to 69%
stenosis. They also felt that a PSV ?230 cm/s was consis-
tent with the diagnosis of ?70% to 99% stenosis. Other
parameters that were found to be helpful included the
ICA/CCA PSV ratios and the ICA EDVs, both of which
could vary depending on different clinical factors and were
thus considered to be useful adjuncts; for example, an EDV
of ?40 cm/s and an ICA/CCA PSV ratio of ?2 were
consistent with 50% to 69% stenosis, and an EDV of ?100
cm/s and a ratio of ?4 were consistent with 70% to 99%
stenosis.2
Fig 1. Sensitivity vs specificity receiver-operating characteristic
(ROC) curves comparing peak systolic velocity (PSV), end-diastolic
velocity (EDV), diastolic ratio (DR), and systolic ratio (SR) for
normal carotids. AUC, Area under the curve.
Fig 2. Sensitivity vs specificity receiver-operating characteristic
(ROC) curves comparing peak systolic velocity (PSV), end-diastolic
velocity(EDV),diastolicratio(DR),andsystolicratio(SR)for?50%
stenosis. AUC, Area under the curve.
Fig 3. Receiver-operating characteristic (ROC) curves compar-
ing peak systolic velocity (PSV), end-diastolic velocity (EDV),
diastolic ratio (DR), and systolic ratio (SR) for ?70% to 99%
stenosis. AUC, Area under the curve.
JOURNAL OF VASCULAR SURGERY
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AbuRahma et al 57