Carotid Stenosis Criteria

7/31/2019 Carotid Stenosis Criteria

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Diagnostic Ultrasound Criteria forDiagnostic Ultrasound Criteria for

CarotidCarotid StenosisStenosis

ConsenusConsenus for a new Standardfor a new Standard

John Gocke MD, MPH , RVTJohn Gocke MD, MPH , RVTMedical Director, Midwest Heart SpecialistsMedical Director, Midwest Heart Specialists

Vascular LaboratoryVascular Laboratory


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We all need open passagewaysWe all need open passageways

Which have no impediments


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High Grade ICAHigh Grade ICAstenosisstenosis

Sagittal or long view Transverse view


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The relationship betweenThe relationship between stenosisstenosis &&

velocityvelocity

The tighter theThe tighter the stenosisstenosis, the higher the Peak systolic, the higher the Peak systolic

velocity (PSV), & the greater the turbulencevelocity (PSV), & the greater the turbulence ------until youuntil you

get so tight a narrowing that only a trickle comesget so tight a narrowing that only a trickle comesthrough the orifice, or eventually nothing at all.through the orifice, or eventually nothing at all.

Somewhere between 65 % and 75% diameter luminalSomewhere between 65 % and 75% diameter luminal

narrowing, the end diastolic velocity (narrowing, the end diastolic velocity (edvedv) begins to) begins toincrease noticeably, then substantially.increase noticeably, then substantially.


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DuplexDuplex ..meansmeanstwotwomodalitiesmodalities

ImageImage

VelocityVelocity


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The Saga of the Garden Hose & itsThe Saga of the Garden Hose & its

NozzleNozzle


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Color Duplex andColor Duplex and angioangio


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Methods of calculatingMethods of calculating stenosisstenosisangiographicallyangiographically


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Dr. EugeneDr. Eugene StrandnessStrandness

University of WashingtonUniversity of Washington

First Carotid Duplex CriteriaFirst Carotid Duplex Criteria--early 1980early 1980ss

Validated based on comparing the highestValidated based on comparing the highest

DuplexDuplex--derived velocities to the angiographicderived velocities to the angiographicrelationship between the point of narrowing torelationship between the point of narrowing to

the estimated normal diameter of the Carotidthe estimated normal diameter of the Carotid

BulbBulb


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His criteria worked splendidly for many yearsHis criteria worked splendidly for many years

and still do, but 2 problems arose withand still do, but 2 problems arose withcontinued primary use:continued primary use:

Most if not all standard measurements comparisonsMost if not all standard measurements comparisons

for velocity/for velocity/stenosisstenosis correllationcorrellationwere switchingwere switchingover to NASCET criteriaover to NASCET criteria

His criteria were criticized for havingHis criteria were criticized for having too wide of atoo wide of a

moderatemoderate stenosisstenosis rangerange in the > 50% categoryin the > 50% categoryofofnot being able to discern the ACASnot being able to discern the ACAS cutpointcutpoint of 60%of 60%or the NASCET criteria of 70%.or the NASCET criteria of 70%.


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StenosisStenosis ranges (ranges (StrandnessStrandness))

00

11--15 %15 %

1616-- 49%49%

5050 --79%79% (too large of a range)(too large of a range) 8080--99%99%

100% (occlusion)100% (occlusion)


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NormalNormal = no plaque, no turbulence PSV 125 cm/second, greater spectral

broadening throughout systole, heavier, more prominent plaquebroadening throughout systole, heavier, more prominent plaque

formation present.formation present.

8080--99%99% stenosisstenosis = PSV > 125 cm/sec, marked spectral= PSV > 125 cm/sec, marked spectral

broadening and turbulence, severe plaque formation,broadening and turbulence, severe plaque formation, and endand enddiastolic velocity elevated > 140cm/seconddiastolic velocity elevated > 140cm/second

OcclusionOcclusion


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Over the years, many hybrid andOver the years, many hybrid and

differentdifferent stenosisstenosis measurementmeasurement

algorithms arosealgorithms arose

Each with their own set cut points of validity, mostEach with their own set cut points of validity, most

appropriately based on ROC curve analysis.appropriately based on ROC curve analysis.

The problem was, there were just so many differentThe problem was, there were just so many differentvelocity criteria being used that there was substantialvelocity criteria being used that there was substantial

difficulty getting comparisons and standardization indifficulty getting comparisons and standardization in

readings between facilities.readings between facilities.


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Enter the Society of Radiologists inEnter the Society of Radiologists in

UltrasoundUltrasound.2002.2002

They invited a number of vascular ultrasoundThey invited a number of vascular ultrasound

experts from around the country, representingexperts from around the country, representingdifferent specialties all practicing in the field fordifferent specialties all practicing in the field for

the purpose of distilling the worldthe purpose of distilling the worlds literature ons literature on

the topic, and, based on the science presentedthe topic, and, based on the science presented

and discussed, their charge was to come up withand discussed, their charge was to come up with

a set of consensus panel recommendations fora set of consensus panel recommendations for

assessing carotidassessing carotid stenosisstenosis using ultrasound thatusing ultrasound that

could be used as guidelines for practitioners.could be used as guidelines for practitioners.


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SRU Consensus ConferenceSRU Consensus Conference

In short, we were locked into a hotel in SanIn short, we were locked into a hotel in San

Francisco in October 2002 with Dr. Ed GrantFrancisco in October 2002 with Dr. Ed Grant((ConsenusConsenus panel chair) for 2 days and were notpanel chair) for 2 days and were not

allowed out until we had a written document.allowed out until we had a written document.


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Radiology November 2003 229: 340-346


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DuplexDuplex ..meansmeanstwotwomodalitiesmodalities

ImageImage

VelocityVelocity


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Additional Doppler parametersAdditional Doppler parameters

other than ICA PSVother than ICA PSV

Useful asUseful as internal checksinternal checks

When for certain reasons, relying on ICA PSVWhen for certain reasons, relying on ICA PSV

alone may not be best or most accurate.alone may not be best or most accurate.


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The ICA/CCA ratioThe ICA/CCA ratio becomes important to use inbecomes important to use in

situations where the ICA PSV may not be by itself,situations where the ICA PSV may not be by itself,representative of the extent of ICA disease due to:representative of the extent of ICA disease due to:

Tandem ICATandem ICA stenosisstenosis

Elevated CCA velocities orElevated CCA velocities or stenosisstenosis ContralateralContralateral highhigh--grade ICAgrade ICA stenosisstenosis

Discrepancy between visual assessment of plaque and ICADiscrepancy between visual assessment of plaque and ICA

PSVPSV

Significantly altered Cardiac output states (high or low)Significantly altered Cardiac output states (high or low)


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For example, in the case of significantly lowFor example, in the case of significantly lowcardiac output states, ICA PSV may becardiac output states, ICA PSV may be

disproportionately low when compared to thedisproportionately low when compared to the

ICA/ CCA ratio. In such cases, heavy relianceICA/ CCA ratio. In such cases, heavy reliance

on the importance of the ICA/CCA ratio ison the importance of the ICA/CCA ratio is

important.important.


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The panel believed that inclusion in the finalThe panel believed that inclusion in the final

report ofreport ofreasonsreasonswhy the interpreting physicianwhy the interpreting physician

may not have used the ICA PSV as the primarymay not have used the ICA PSV as the primarydiagnostic criterion is important.diagnostic criterion is important.


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End diastolic velocityEnd diastolic velocity

Really starts to increase at higher levels ofReally starts to increase at higher levels ofstenosisstenosis,,

usually at or above 75% diameter luminal narrowing.usually at or above 75% diameter luminal narrowing.


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Additional criteria recommendedAdditional criteria recommended

The presence of plaque or otherThe presence of plaque or other intimalintimal

irregularities is essential for the presence of trueirregularities is essential for the presence of truestenosisstenosis. This gray scale finding should be used. This gray scale finding should be used

as aas a reality checkreality check on the velocities.on the velocities.

Color Doppler appearance of the lumen shouldColor Doppler appearance of the lumen should

be used.be used.


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TortuosityTortuosity related Bruitrelated Bruit


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Consensus criteria apply to the nativeConsensus criteria apply to the native

carotid bifurcation onlycarotid bifurcation only


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Why is the new criteria so important ?Why is the new criteria so important ?

It represented the first real consensus onIt represented the first real consensus on

acceptable guidelines that could be usedacceptable guidelines that could be usednationally for setting standards internally in anationally for setting standards internally in a

vascular laboratory.vascular laboratory.

Furthered the concept that adherence toFurthered the concept that adherence toscientific principles andscientific principles and standardiztionstandardiztion of certainof certaininstrumentation, technique, and diagnosticinstrumentation, technique, and diagnostic

criteria leads to better quality vascular ultrasoundcriteria leads to better quality vascular ultrasoundand patient care.and patient care.


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Why is the new criteria so important ?Why is the new criteria so important ?

RealityRealitymost vascularmost vascular

surgeons andsurgeons and

interventionalistsinterventionalistswonwontt

touch the patient until thetouch the patient until the

stenosisstenosis> 70 % and> 70 % andapproaches 80 % and moreapproaches 80 % and more

people were asking to havepeople were asking to have

either a 60 % or a 70%either a 60 % or a 70%

cutpointcutpointon ultrasound.on ultrasound.


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Important point from the ConsensusImportant point from the Consensus

PanelPanel

These consensus criteria do not in any wayThese consensus criteria do not in any wayinvalidate nor are meant to discourage aninvalidate nor are meant to discourage an

individual vascular laboratoryindividual vascular laboratorys modification ofs modification of

these criteria based on sound internal validationthese criteria based on sound internal validationstrategies.strategies.


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MHS PercentMHS Percent StenosisStenosis RangesRanges NormalNormal

< 50 %< 50 % 11-- 15 % subcategory15 % subcategory

1616--49 % subcategory49 % subcategory

505069 %69 %

> 70 %> 70 %

> 80 % subcategory> 80 % subcategory String sign or near occlusionString sign or near occlusion

OccludedOccluded


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MHSMHS


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Dr.Dr. StrandnessStrandness always stressed and the Consensus Panelalways stressed and the Consensus Panelreiteratesreiterates

Accuracy predicated uponAccuracy predicated upon

Proper angle ofProper angle ofinsonationinsonation = always less than or= always less than or

equal to 60 degrees.equal to 60 degrees.

Proper placement of the Doppler cursor in theProper placement of the Doppler cursor in thecenter of the flow stream with the cursor in thecenter of the flow stream with the cursor in the

direction of flow.direction of flow.


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Normal carotid bifurcationNormal carotid bifurcation


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5050 -- 69 %69 % StenosisStenosis


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Velocities of > 70 %Velocities of > 70 % stenosisstenosis(subset > 80 % )(subset > 80 % )


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Simply put:Simply put: While multiple investigators have found thatWhile multiple investigators have found that

mean Doppler velocities consistently rise as themean Doppler velocities consistently rise as thestenosisstenosis becomes tighter in comparison withbecomes tighter in comparison with

angiography,angiography, there are wide ranges of Dopplerthere are wide ranges of Doppler

values around those means.values around those means.


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Grant et al. Radiology 2000: 214 p 247 -252

Angiographic stenosis compared to Carotid Duplex velocities


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Why do we reportWhy do we reportstenosisstenosisin ain aRange ?Range ?

Significant overlap of velocitiesSignificant overlap of velocitiesat the same level ofat the same level ofstenosisstenosisexistsexiststhis is the reason thatthis is the reason thatstenosesstenosesareare

reportedreportedin rangesin rangesand not specific %.and not specific %.

The higher the velocity, the tighter theThe higher the velocity, the tighter thestenosisstenosis.up to.up toabout 97 %, then the velocities start to decrease (stringabout 97 %, then the velocities start to decrease (string

sign)sign)trickle of flow.trickle of flow.


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New diagnostic criteriaNew diagnostic criteria

Radiology November 2003 229: 340-346


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Guidant 2004

October 28-30, 2004

Chicago Westin River North Hotel

Downtown Chicago

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Carotid Stenosis Criteria