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2/19/2013
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Carotid Plaque & IMT Carotid Plaque & IMT
Imaging: Where Do We Imaging: Where Do We
Stand?Stand?
Roger S. Blumenthal, MD, FACCRoger S. Blumenthal, MD, FACC
Professor of MedicineProfessor of Medicine
Director, Johns Hopkins Ciccarone Center Director, Johns Hopkins Ciccarone Center for the Prevention of Heart Diseasefor the Prevention of Heart Disease
Disclosures: NoneDisclosures: None
ObjectivesObjectives
�� Limits to FRS predictionLimits to FRS prediction
�� Carotid ultrasound as tool to predict Carotid ultrasound as tool to predict
cardiovascular disease riskcardiovascular disease risk
�� Carotid plaque presenceCarotid plaque presence
�� Carotid intimaCarotid intima--media thickness (CIMT) media thickness (CIMT)
measurementmeasurement
�� Consensus statement from ASE/SVMConsensus statement from ASE/SVM
Limitations of Current CV Risk Limitations of Current CV Risk
Prediction ModelsPrediction Models
�� Heavily dependent on ageHeavily dependent on age
�� Do not account on changes in patient’s health Do not account on changes in patient’s health status over timestatus over time
�� Focused on shortFocused on short--term (10term (10--year) riskyear) risk
�� Family history not incorporated into estimatesFamily history not incorporated into estimates
�� Patients with high levels of a single risk factor Patients with high levels of a single risk factor may not be correctly classified solely on FRSmay not be correctly classified solely on FRS
�� Smoking considered as present or absent onlySmoking considered as present or absent only
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Advantages of Carotid Ultrasound as Advantages of Carotid Ultrasound as
an Imaging Modalityan Imaging Modality
�� NonNon--invasive, safeinvasive, safe
�� InexpensiveInexpensive
�� Readily available, Readily available, portable, and quickportable, and quick
�� Plaque visualizationPlaque visualization
�� HemodynamicsHemodynamics
�� OfficeOffice--based assessmentbased assessment
Ultrasound Ultrasound Assessment of Assessment of
Carotid Carotid IMT and Plaque PresenceIMT and Plaque Presence
mediamedia
adventitia
intimaplaque
Advantages of Carotid Advantages of Carotid Study To Study To
Refine Refine Risk Prediction Risk Prediction �� Completely noninvasive Completely noninvasive –– no radiation, no harmful no radiation, no harmful
exposures, no known biological effectsexposures, no known biological effects
�� Identifies range of disease Identifies range of disease –– increased CIMT, nonincreased CIMT, non--occlusive occlusive
plaque, stenosisplaque, stenosis
�� Normal values are known Normal values are known –– 2525--85 years old, both sexes, most 85 years old, both sexes, most
races/ethnicitiesraces/ethnicities
�� Predicts future MI, CHD death, and stroke, with incremental Predicts future MI, CHD death, and stroke, with incremental
predictive powerpredictive power
�� Track serial changesTrack serial changes
�� Recommended by NCEP ATP III, AHA, ACC, ASE, SVM, Recommended by NCEP ATP III, AHA, ACC, ASE, SVM, SAIP, and ESC to assist with CVD risk stratificationSAIP, and ESC to assist with CVD risk stratification
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Carotid Duplex ProtocolCarotid Duplex Protocol
�� Presence or absence of plaquePresence or absence of plaque
�� Morphology of plaqueMorphology of plaque
�� Calcified / Calcified / echolucentecholucent / heterogeneous/ heterogeneous
�� Degree of stenosisDegree of stenosis
�� Spectral Spectral dopplerdoppler (angle(angle--corrected) corrected)
�� Quantitative; measurement of hemodynamic changesQuantitative; measurement of hemodynamic changes
�� Peak systolic velocityPeak systolic velocity, end, end--diastolic velocity, ICA/CCA Ratiodiastolic velocity, ICA/CCA Ratio
�� Sensitivity ~85%, specificity ~90% Sensitivity ~85%, specificity ~90%
�� Similar to MRA for occlusion and stenosis > 70%Similar to MRA for occlusion and stenosis > 70%
Color Mode: Echolucent PlaqueColor Mode: Echolucent Plaque
Case 1Case 1
�� 50 year old female50 year old female�� HypertensionHypertension
�� Current smokerCurrent smoker
�� No DMNo DM
�� No known CAD No known CAD
�� TC 212 HDL 57 LDL 126 TG 144TC 212 HDL 57 LDL 126 TG 144
�� FRS 6%FRS 6%
�� Would the presence of carotid plaque on Would the presence of carotid plaque on ultrasound alter her management?ultrasound alter her management?
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How is Plaque Defined?How is Plaque Defined?
�� Focal wall thickening Focal wall thickening that is at least 50% that is at least 50% greater than that of greater than that of surrounding vessel wallsurrounding vessel wall
OROR
�� Focal thickening of IMTFocal thickening of IMTgreater than 1.5 mmgreater than 1.5 mm
Stein JH, et al.. J Am Soc Echocardiogr 2008.Stein JH, et al.. J Am Soc Echocardiogr 2008.Mannheim Consensus Cerebrovasc Dis 2007.Mannheim Consensus Cerebrovasc Dis 2007.
Carotid Plaque and CADCarotid Plaque and CAD
�� Patients with occlusive carotid disease 7 times Patients with occlusive carotid disease 7 times
more likely to have positive exercise stress test more likely to have positive exercise stress test
than patients with normal carotid arteriesthan patients with normal carotid arteries
�� Presence of carotid plaques associated with Presence of carotid plaques associated with
angiographic CAD angiographic CAD
�� MultiMulti--vessel CAD associated with higher vessel CAD associated with higher
prevalence of carotid plaque than singleprevalence of carotid plaque than single--vessel vessel
diseasedisease Bruckert E et al. Atherosclerosis 1992
Nowak J et al. Stroke 1998
Skaguchi M et al. Ultrasound Med Biol 2003
Prospective Studies Relating Carotid Plaque Prospective Studies Relating Carotid Plaque Presence to Incident CVD in Asymptomatic Presence to Incident CVD in Asymptomatic
IndividualsIndividualsStudyStudy NN AgeAge YrsYrs EventEvent Adjusted HR Adjusted HR
ARICARIC 12,37512,375 4545--6464 77MI, CHD MI, CHD deathdeath
2.96 (1.542.96 (1.54--3.30)3.30)
KIHDKIHD 1,2881,288 4242--6060 ≤2≤2 MIMI 4.15 (1.54.15 (1.5--11.47)11.47)
MDCSMDCS 5,1635,163 4646--6868 77MI, CHD MI, CHD deathdeath
1.81 (1.141.81 (1.14--2.87)2.87)
Northern Northern ManhattanManhattan
1,9391,939 >40>40 66 StrokeStroke 3.1 (1.13.1 (1.1--8.5)8.5)
RotterdamRotterdam 6,389 6,389 >55>55 77--1010 MIMI 1.83 (1.271.83 (1.27--2.62)2.62)
San San DanielleDanielle
1,3481,348 1818--9999 1212Stroke, TIA, Stroke, TIA,
vascular vascular deathdeath
10.4 (6.410.4 (6.4--17.1)17.1)
Yao CityYao City 1,2891,289 6060--7474 55 StrokeStroke 3.2 (1.43.2 (1.4--7.1)7.1)
Modified from Johnson HM, et al. J Nuc Cardiol 201 1;18:153Modified from Johnson HM, et al. J Nuc Cardiol 201 1;18:153
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Case 1 Carotid Duplex: Screen for plaqueCase 1 Carotid Duplex: Screen for plaque
Does Plaque Presence (Increased CV Risk) Does Plaque Presence (Increased CV Risk)
Justify Initiation of Preventive Therapies?Justify Initiation of Preventive Therapies?
�� Smoking cessationSmoking cessation
�� Smokers shown images of carotid plaques were more likely to Smokers shown images of carotid plaques were more likely to stop smoking at 6 monthsstop smoking at 6 months
�� Quit Rates 22% versus 6%, p=0.003 in those who had plaqueQuit Rates 22% versus 6%, p=0.003 in those who had plaque
Bovet P, et al. Bovet P, et al. PrevPrev Med 2002.Med 2002.
�� Lifestyle modificationLifestyle modification
�� Patients more likely to adhere to diet and exercise Patients more likely to adhere to diet and exercise
recommendations after seeing pictures of plaquerecommendations after seeing pictures of plaque
�� Would you initiate treatment with a statin?Would you initiate treatment with a statin?
�� What should be her target LDLWhat should be her target LDL--C?C?
“Less is “Less is NotNot More”More”
“PPIs for persons with nonulcer dyspepsia, opioid “PPIs for persons with nonulcer dyspepsia, opioid
medications for persons with chronic medications for persons with chronic
nonmalignant pain, and STATIN medications nonmalignant pain, and STATIN medications
for persons without CAD are all examples of the for persons without CAD are all examples of the
widespread use of medications with known widespread use of medications with known adverse effects despite the ABSENCE of adverse effects despite the ABSENCE of
DATA FOR PATIENT BENEFIT for these DATA FOR PATIENT BENEFIT for these
indications.”indications.”
Redberg R et al. Arch Intern Med. Dec 13 2010.
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Case 2Case 2
�� 43 year old female43 year old female
�� Family history of premature CHDFamily history of premature CHD
�� Father CABG at age 49, brother MI at age 47Father CABG at age 49, brother MI at age 47
�� No hypertension, no DMNo hypertension, no DM
�� NonNon--smokersmoker
�� TC 192, HDL 52, LDL 122, TG 92TC 192, HDL 52, LDL 122, TG 92
�� Framingham Risk < 1%Framingham Risk < 1%
Carotid Ultrasound: No PlaqueCarotid Ultrasound: No Plaque
Do CIMT MeasurementDo CIMT Measurement
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Carotid IntimaCarotid Intima--Media Thickness (IMT)Media Thickness (IMT)
US Measure of ATHUS Measure of ATH
EndotheliumEndothelium
Intima
Media
HIGH RESOLUTION
B-MODE ULTRASOUND
CCA
CCAbulb
bulb
Near wall
Far wall
IntimaMediaAdventitia
IntimaMediaAdventitia
Normal and Abnormal Carotid
Intima-Media Thickness
TOTAL IMT = Σ Σ Σ Σ IMT ii =1
n
where IMTi = Mean (A j – B j) or Max (A j – B j)
Aj
B jn
Plaquemeasured separately
IMTi
CAROTID IMT CALCULATION
Distal 1 cm of far wall of CCA
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Why Use the Distal CCA?Why Use the Distal CCA?
�� Size of vesselSize of vessel
�� Superficial locationSuperficial location
�� Ease of accessibilityEase of accessibility
�� In comparison to ICA and bulb which is more In comparison to ICA and bulb which is more
dependent on technical expertisedependent on technical expertise
�� Limited movementLimited movement
Stein JH, et al. ASE Consensus Statement. Stein JH, et al. ASE Consensus Statement. J Am Soc Echocardiogr 2008J Am Soc Echocardiogr 2008
Clinical CIMT MeasurementClinical CIMT Measurement
ASE Task Force
Recommendation
� Distal 1 cm of far wall of each CCA
� Obtain measurement and compare with values from
normative data set
Distribution of CIMT in the General Distribution of CIMT in the General
Population: ARIC StudyPopulation: ARIC Study
0.64 0.650.74
0.80.75 0.78
0.930.98
0.85 0.85
1.091.14
0
0.2
0.4
0.6
0.8
1
1.2
1.4
LCCA RCCA L Bulb R Bulb
0.72 0.71
0.84 0.850.83 0.84
1.03 1.040.99 1.01
1.311.21
0
0.2
0.4
0.6
0.8
1
1.2
1.4
LCCA RCCA L Bulb R Bulb
0.61 0.61
0.73 0.750.71 0.71
0.88 0.910.81
0.93
1.091.16
0
0.2
0.4
0.6
0.8
1
1.2
1.4
LCCA RCCA L Bulb R Bulb
0.70.66
0.82
0.66
0.8 0.77
1.06
0.77
0.93 0.9
1.23
0.9
0
0.2
0.4
0.6
0.8
1
1.2
1.4
LCCA RCCA L Bulb R Bulb
Black Women
White Women
Black Men
White Men
Howard G, et al Stroke 1993; 24:1297-1304
45 yrs
55 yrs65 yrs
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Distribution of CIMT in General Population: AXA Stu dyDistribution of CIMT in General Population: AXA Stu dy
Gariepy J et al Arterioscler Thromb Vasc Biol 1998
Modified from Johnson HM, et al. J Nuc Cardiol 201 1;18:153Modified from Johnson HM, et al. J Nuc Cardiol 201 1;18:153
Prospective Studies Relating CCA CIMT to Prospective Studies Relating CCA CIMT to Incident CVD Events in Asymptomatic IndividualsIncident CVD Events in Asymptomatic Individuals
StudyStudy NN AgeAge YrsYrs CV EventCV Event CutpointCutpoint Adjusted RR Adjusted RR (95% CI)(95% CI)
ARICARIC 12,84112,841 4545--6464 55 MI, CHD deathMI, CHD death tertiletertile W: 2.53 (1.02W: 2.53 (1.02--6.26) 6.26) M: 2.02 (1.32M: 2.02 (1.32--3.09)3.09)
14,21414,214 4545--64 64 77 strokestroke tertiletertile W: 2.32 (1.09W: 2.32 (1.09--4.94) 4.94) M: 2.24 (1.26M: 2.24 (1.26--4.00)4.00)
CAPSCAPS 5,0565,056 1919--9090 44 MI, stroke, deathMI, stroke, death quartilequartile 1.85 (1.091.85 (1.09--3.15)3.15)
CHSCHS 4,4764,476 >65>65 66 MIMI quintilequintile 3.61 (2.133.61 (2.13--6.11)6.11)
strokestroke quintilequintile 2.57 (1.642.57 (1.64--4.02)4.02)
KIHDKIHD 1,2571,257 4242--6060 33 MIMI >1.0 mm>1.0 mm 2.1 (0.82.1 (0.8--5.2)5.2)
MDCSMDCS 5,1635,163 4646--6868 77 MI, CHD deathMI, CHD death tertiletertile 1.50 (0.811.50 (0.81--2.59)2.59)
MESAMESA 6,698 6,698 4545--8484 44 CHD, CHD deathCHD, CHD death quartilequartile 2.3 (1.42.3 (1.4--3.8)3.8)
RotterdamRotterdam 6,389 6,389 >55>55 77--1010 MIMI quartilequartile 1.95 (1.191.95 (1.19--3.19)3.19)
San DanielleSan Danielle 1,3481,348 1818--9999 1212 Stroke, TIA, Stroke, TIA, vascular deathvascular death
>1.0 mm>1.0 mm 5.6 (3.25.6 (3.2--10.1)10.1)
TromsoTromso 6,2266,226 2525--8484 55 MIMI quartilequartile W: 2.86 (1.07W: 2.86 (1.07--7.65) 7.65) M: 1.73 (0.98M: 1.73 (0.98--3.06)3.06)
Yao CityYao City 1,2891,289 6060--7474 55 strokestroke quartilequartile 4.9 (1.94.9 (1.9--12.0)12.0)
CIMT Progression and Clinical CV EventsCIMT Progression and Clinical CV Events
Hodis HN, et al. Ann Intern Med 1998;128:262-9.
CIMT: R distal CCA far wall
RR 2.2 per 0.03 mm/year; P < 0.001
RRQ4/Q1 2.8
N=188
Non-
smoking
Men ages
45-59
Prior
CABG
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Clinical Trials: CClinical Trials: Carotid IMT as an outcome measurearotid IMT as an outcome measureCarotid IMT and StatinsCarotid IMT and Statins
Pravastatin:
PLAC-II (Pravastatin, Lipids, and Ath in Carotid Arteries)
KAPS (Kuopio Atherosclerosis Prevention Study)
REGRESS (Regression growth Evaluation Statin Study)
LIPID (Long-term Intervention with Pravastatin in Ischemic Dis)
Lovastatin:
MARS (Monitored Atherosclerosis Regression Study)
ACAPS (Asymptomatic Carotid Artery Progression Study)
*Carotid IMT progression meets accepted definitions of a surrogate for cardiovascular disease endpoints in statin trials
*NOT FDA-approved surrogate end point of vascular events
METEOR TrialMETEOR Trial
�� 984 subjects984 subjects
�� Age as only CVD risk factor (mean 57 yrs) ORAge as only CVD risk factor (mean 57 yrs) OR
�� FRS < 10%FRS < 10%
�� Modest CIMT thickening (focal CIMT > 1.2 mm)Modest CIMT thickening (focal CIMT > 1.2 mm)
�� Elevated LDLElevated LDL--C (range 120C (range 120--190 mg/dL)190 mg/dL)
�� Randomized to 40 mg rosuvastatin versus Randomized to 40 mg rosuvastatin versus
placeboplacebo
�� CIMT progression rate over 2 years assessedCIMT progression rate over 2 years assessed
Crouse, J. R. et al. JAMA 2007;297:1344-1353.
METEOR: Change in Maximum CIMT for the Primary End Point
∆ CIMTmax = ∆ CIMTmax = --0.0145 0.0145 mm/yearmm/year
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•3300 men and women with vascular disease
• HDL-C ≤ 40 (<50 F)• TG 150-400 • LDL-C ≤ 180
Simvastatin Simvastatin+Niacin
1° Endpoint: CHD Death, MI, CVA, or hi-risk ACS
hospitalization
AIM-HIGH Study Design
Equivalent Goal LDL
(AIM HIGH) Results(AIM HIGH) Results
�� 3414 subjects ; age 64; 34% with T2DM and 71% with MetS; 94% 3414 subjects ; age 64; 34% with T2DM and 71% with MetS; 94%
prior statinsprior statins
�� Randomized to simva to reduce LDLRandomized to simva to reduce LDL--C < 80 mg/dL; then niacin C < 80 mg/dL; then niacin
ER 2 gm in 1718 or PBO in 1696ER 2 gm in 1718 or PBO in 1696
�� Baseline lipids: LDLBaseline lipids: LDL--C 71C 71TG 161TG 161
HDL 35HDL 35
�� Primary endpoint composite: no difference after 32 months; trial Primary endpoint composite: no difference after 32 months; trial
stopped for futility after 511 events of 800 planned. stopped for futility after 511 events of 800 planned.
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CIMT ChallengesCIMT Challenges
�� Ultrasound protocol heterogeneityUltrasound protocol heterogeneity�� Image acquisition segment: CCA/Bulb/ICAImage acquisition segment: CCA/Bulb/ICA
�� Wall: near, farWall: near, far�� Type of measure: max, mean of max (2Type of measure: max, mean of max (2--12)12)
�� Unilateral or bilateralUnilateral or bilateral
�� Measurement variabilityMeasurement variability�� Scanning equipmentScanning equipment
�� SonographersSonographers�� Reading equipmentReading equipment�� ReadersReaders
�� Limited ReimbursementLimited Reimbursement
Back to Case 2Back to Case 2
�� 43 year old female43 year old female
�� Family history of premature CHDFamily history of premature CHD
�� Father CABG at age 49, brother MI at age 47Father CABG at age 49, brother MI at age 47
�� No hypertension, no DMNo hypertension, no DM
�� NonNon--smokersmoker
�� TC 192, HDL 52, LDL 122, TG 92TC 192, HDL 52, LDL 122, TG 92
�� Framingham Risk < 1%Framingham Risk < 1%
Case 2: CIMT MeasurementCase 2: CIMT Measurement
�� CIMT 0.70 mmCIMT 0.70 mm
�� Between 90Between 90thth and 95and 95thth
PrecentilesPrecentiles
�� CV Risk: CV Risk: IncreasedIncreased
�� Although FRS < 1%, Although FRS < 1%,
CIMT measurement CIMT measurement
indicates increased CV indicates increased CV
risk in this patientrisk in this patient
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ASE Consensus StatementASE Consensus Statement
Stein JH, et al. J Am Soc Echocardiogr 2008;21:93Stein JH, et al. J Am Soc Echocardiogr 2008;21:93
Who Should be Screened?Who Should be Screened?
�� Intermediate CVD risk Intermediate CVD risk
�� FRS 6%FRS 6%--20% without established CHD, DM20% without established CHD, DM
�� Family history of premature CVD in first degree Family history of premature CVD in first degree
relative (men < 55 years, women < 65 years)relative (men < 55 years, women < 65 years)
�� Women younger than 60 years with at least 2 Women younger than 60 years with at least 2
CVD risk factorsCVD risk factors
�� Not recommended in patients with established Not recommended in patients with established
atherosclerotic diseaseatherosclerotic disease
ASE Consensus Statement: CV RiskASE Consensus Statement: CV Risk
�� CVD Risk CVD Risk IncreasedIncreased�� If CIMT ≥ 75If CIMT ≥ 75thth percentile for age, race, sexpercentile for age, race, sex
�� If carotid plaque is presentIf carotid plaque is present�� Greater than 50% protrusionGreater than 50% protrusion
�� Focal IMT > 1.5 mmFocal IMT > 1.5 mm
�� CVD Risk CVD Risk Average (unchanged)Average (unchanged)�� CIMT in the 25CIMT in the 25thth to 75to 75thth percentilepercentile
�� CVD Risk CVD Risk LowerLower�� CIMT ≤ 25CIMT ≤ 25thth percentilepercentile
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Proposed Screening AlgorithmProposed Screening Algorithm
FRS 6%-20%Family History Premature CVD
F < 60 years with 2 CVD Risk Factors
SCREENING CAROTID DUPLEX
PLAQUE PRESENT
STOP
PLAQUE ABSENT
CIMT MEASUREMENT
ARIC Study: CIMT and Plaque in ARIC Study: CIMT and Plaque in
CHD Risk Prediction CHD Risk Prediction
�� 13,145 subjects free of CHD or stroke (4513,145 subjects free of CHD or stroke (45--65yr)65yr)
�� Mean follow up 15.1 yearsMean follow up 15.1 years
�� 1,812 incident CHD events1,812 incident CHD events
�� Risk Prediction Models (10Risk Prediction Models (10--yr CHD risk)yr CHD risk)
�� Traditional Risk Factors (TRF)Traditional Risk Factors (TRF)
�� TRF + CIMTTRF + CIMT
�� TRF + PlaqueTRF + Plaque
�� TRF + CIMT + PlaqueTRF + CIMT + Plaque
Nambi et al. JACC 2010;55:1600-7.
CIMT and Plaque DefinitionsCIMT and Plaque Definitions
�� CIMTCIMT
�� Mean of mean of distal CCA, bifurcation, and Mean of mean of distal CCA, bifurcation, and
proximal ICA measurements (both right and left)proximal ICA measurements (both right and left)
�� Categorized as: <25Categorized as: <25thth, 25, 25thth--7575thth, >75, >75thth percentilespercentiles
�� Plaque Plaque –– 2 of 3 criteria:2 of 3 criteria:
�� Abnormal wall thickness (CIMT > 1.5 mm)Abnormal wall thickness (CIMT > 1.5 mm)
�� Abnormal wall shape (protrusion into lumen)Abnormal wall shape (protrusion into lumen)
�� Abnormal wall texture (brighter echoes)Abnormal wall texture (brighter echoes)
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ARIC Results: CHD Incidence RateARIC Results: CHD Incidence Rate
Nambi et al. JACC 2010;55:1600-7
ARIC Results: Effect on AUCARIC Results: Effect on AUC
Nambi et al. JACC 2010;55:1600-7
ARIC: Reclassification of SubjectsARIC: Reclassification of Subjects
�� TRF + CIMT + Plaque resulted in reclassification of TRF + CIMT + Plaque resulted in reclassification of
~23% of subjects~23% of subjects
�� More subjects reclassified to lower risk groupMore subjects reclassified to lower risk group
�� 12.4% vs. 11% 12.4% vs. 11%
�� No subjects were reclassified from low (<5%) to high No subjects were reclassified from low (<5%) to high
risk (>20%)risk (>20%)
�� No subjects reclassified from high to low riskNo subjects reclassified from high to low risk
�� Results similar in FRSResults similar in FRS--based TRF modelbased TRF model
�� www.ARICnews.netwww.ARICnews.net (CHD risk calculator)(CHD risk calculator)
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2010 ACCF/AHA Guideline for Assessment 2010 ACCF/AHA Guideline for Assessment of Cardiovascular Risk in Asymptomatic of Cardiovascular Risk in Asymptomatic
AdultsAdultsRecommendation for Measurement of Carotid Recommendation for Measurement of Carotid IntimaIntima--Media ThicknessMedia Thickness
CLASS IIa (Level of Evidence: B)CLASS IIa (Level of Evidence: B)
“Measurement of carotid artery intima“Measurement of carotid artery intima--media media thickness is reasonable for cardiovascular risk thickness is reasonable for cardiovascular risk assessment in asymptomatic adults at intermediate assessment in asymptomatic adults at intermediate risk (43,44). Published recommendations on risk (43,44). Published recommendations on required equipment, technical approach, and required equipment, technical approach, and operator training and experience for performance of operator training and experience for performance of the test must be carefully followed to achieve highthe test must be carefully followed to achieve high --quality results (44).quality results (44).
Greenland P, et al. J Am Coll Cardiol 2011 (in pres s)Greenland P, et al. J Am Coll Cardiol 2011 (in pres s)
ASE/SVM Consensus StatementASE/SVM Consensus Statement
•• Increased CVD risk ifIncreased CVD risk if–– CIMT CIMT ≥75≥75thth percentile for age, sex, racepercentile for age, sex, race
–– Presence of carotid plaque (> 50 % Presence of carotid plaque (> 50 % protrusion or focal IMT ≥1.5 mm)protrusion or focal IMT ≥1.5 mm)
•• Recommendations Recommendations –– Scanning techniqueScanning technique
–– InterpretationInterpretation
–– ReportingReporting
–– Training and certificationTraining and certificationStein JH, et al. J Am Soc Echocardiogr 2008;21:93Stein JH, et al. J Am Soc Echocardiogr 2008;21:93
ASE/SVM Consensus StatementASE/SVM Consensus StatementPatient SelectionPatient Selection
•• “Intermediate” risk“Intermediate” risk–– 1010--year Framingham risk of 6year Framingham risk of 6--20% 20% –– Not already at high risk Not already at high risk
•• Family history of premature CV disease in a Family history of premature CV disease in a firstfirst--degree relative (men <55, women <65 yo)degree relative (men <55, women <65 yo)
•• Younger people with severe abnormalities in a Younger people with severe abnormalities in a single risk factor who are not being treated single risk factor who are not being treated with medications (with medications ( e.g.,e.g., genetic dyslipidemia, genetic dyslipidemia, heavy smoker) heavy smoker)
•• Women <60 years old with Women <60 years old with ≥≥2 CV risk factors2 CV risk factorsStein JH, et al. J Am Soc Echocardiogr 2008;21:93Stein JH, et al. J Am Soc Echocardiogr 2008;21:93
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•• Level I: Level I: NoNo imaging testsimaging tests
•• Level Level IIaIIa: : CIMT, CAC, ECG (HTN/DM), CIMT, CAC, ECG (HTN/DM), ABIABI
•• Level Level IIbIIb: : TTE (HTN), stress ECG, TTE (HTN), stress ECG, stress MPI (DM/stress MPI (DM/FHxFHx/CAC>400)/CAC>400)
•• Level III: Level III: Brachial FMD, arterial Brachial FMD, arterial stiffness, CTA, MRA plaquestiffness, CTA, MRA plaque
Greenland P, et al. J Am Coll Cardiol 2011 (in pres s)Greenland P, et al. J Am Coll Cardiol 2011 (in pres s)
2010 ACCF/AHA Guideline for Assessment 2010 ACCF/AHA Guideline for Assessment of Cardiovascular Risk in Asymptomatic of Cardiovascular Risk in Asymptomatic
AdultsAdults
Objective: To determine whether CIMT has added value
in the 10-year risk prediction (FRS) of first-time MI
or stroke.
Methods: Meta-analysis of 14 population based cohorts,
45,828 individuals median follow-up 11 years:
4,007 MI or strokes observed.
Only 5/14 studies
significant
association
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“… the added value of common CIMT measurements to the Framingham
risk score in the general population was small”: Of 45,828 individuals
from 14 cohort studies worldwide, 0.8% were correctly reclassified.
“In individuals at intermediate risk, the added value was 3.2% in men
and 3.9% in women. Our results suggest, that common CIMT measurements
should not be routinely performed in the general population because
the overall added value is small and unlikely to be of clinical importance”
Objective: to compare improvement in prediction of incident CHD
of 6 risk markers: 1) coronary artery calcium
2) IMT
3) ABI
4) brachial flow-mediated dilatation
5) hsCRP
6) FHx
Methods: 6814 MESA participants from 6 US field centers (1330
intermediate risk participants).
7.6 years follow-up: 94 CHD and 123 CVD events.
AUC and NRI were calculated.
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“Coronary artery calcium, ABI, hsCRP and family history were independent
predictors of incident CHF in intermediate-risk individuals. CAC provided
superior discrimination and risk reclassification compared with other risk
markers.”
“CIMT […] was not associated with incident CHD in multivariable analyses.”
Prospective cohort study, n=6698, age 45-84.
IMT and CAC measured at baseline in 6 field centers
Main outcome: risk of incident CVD (CAD, stroke, CVD death) over 5.3 yrs. of f/u.
MESA: CVD Prediction with CIMT and
CAC• Highest quartile CIMT predicted CVD events:
adjusted HR 2.3 (1.4 – 3.8) to 3.8 (2.2 – 6.4)
• But: adjusted HR higher with CAC (6.0, 3.9 – 9.1)
• Risk factors = 0.772
• RFs + CIMT = 0.782
• RFs + CAC = 0.808
• RFs + CIMT + CAC = 0.811
• CIMT predicted stroke (HRSD = 1.3, p=0.01), but CAC
did not (HRSD = 1.1, p=0.71)Folsom AR, et al. Arch Intern Med 2008;168:1333Folsom AR, et al. Arch Intern Med 2008;168:1333
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Objective: To compare improvement in prediction of incident CHD
with addition of CIMT to Framingham Risk Score
Methods: Mean IMT of ICA and CCA in 2965 participants of
Framingham Offspring Study were measured.
7.2 years follow-up: 296 cardiovascular events.
C-statistic and NRI were calculated.
“We conclude that the intima-media thickness of the common
carotic artery and the intima-media thickness of the ICA are
independent predictors of cardiovascular events among participants
in the Framingham Offspring Study.”
“The maximum intima-media thickness of the ICA, […], contributed
significantly but modestly to the predictive power of the risk factors
used in calculating the FRS and improved risk classification on the
basis of the FRS.”
Unanswered Questions and Future DirectionsUnanswered Questions and Future Directions
�� No study has shown that treatment based on carotid No study has shown that treatment based on carotid
plaque presence or CIMT alters longplaque presence or CIMT alters long--term outcomesterm outcomes
�� Does plaque screening and subsequent intensification Does plaque screening and subsequent intensification
of medical regimens in patients with plaque or of medical regimens in patients with plaque or
increased CIMT prevent cardiovascular events?increased CIMT prevent cardiovascular events?
�� Is this costIs this cost--effective?effective?
�� Need prospective studies to determine effectiveness of Need prospective studies to determine effectiveness of
carotid ultrasound imaging in improving CVD carotid ultrasound imaging in improving CVD
outcomesoutcomes
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• For example:
• Established Atherosclerotic CVD
• FRS, RRS, or Global Risk ≥10%
• Most patients w/ DM or CKD
• CAC>100
High10-Year
Risk
High10-Year
Risk
• For example:
• Age ≥50 + major RF
• FRS, RRS, or Global Risk 5-10%
• CAC>0 + ≤100
• FHx or MetS + age >40 years ���� Consider CAC scan
High Lifetime
Risk
High Lifetime
Risk
• None of above
• 10-yr risk <5%
• Lifetime risk <39%
LowRiskLowRisk
Lifestyle Changes
+
Potent Statin
Lifestyle Changes
+
Discuss Statin
Focus on
Ideal CV Health