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Intravascular Elastography:palpating plaques with the finger of IVUS

C.L. de Korte1, F. Mastik1, J.A. Schaar1,M. Sierevogel1,3, G. Pasterkamp3,

P.W. Serruys1 and A.F.W van der Steen1,2

1Erasmus University, Thoraxcentre, Rotterdam, The Netherlands 2Interuniversity Cardiology Institute of the Netherlands

3Experimental Cardiology Laboratory, University Medical Center, Utrecht, The Netherlands

Supported by Netherlands Organization for Scientific Research (NWO) and the Dutch Technology Foundation (STW)

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Background : Vulnerable plaque

Plaque vulnerability :

Plaque composition• Large lipid pool

Mechanical properties

• High strain region

• Thin fibrous cap• presence of Macrophages

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Background : Principle of elastography

Soft Harduncompressed

compressed

• The response of tissue to mechanical excitation (e.g. compression) is a function of its mechanical properties.

Force Soft Hard

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IVUS elastography

(t1, P1)

(t2, P2)

Processing

IVUS at 100mmHg

IVUS at 80mmHg

IVUS elastogram

strain1%

0%

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strain1%

0%

Picrosirius-red Anti-CD68 antibodyAlpha-actin

Circulation 102(6) 617-623 (2000)

IVUS elastography plaque characterization

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strain1%

0%

Picrosirius-red Anti-CD68 antibodyAlpha-actin

IVUS elastography vulnerable plaque detection

ACC 2002, presentation 1054-20

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Predictive power of elastography to identify the vulnerable plaque

1 - Specificity1.00.75.50.25

Sens

itivi

ty

1.00

.75

.50

.25

0

Strain 1.26 %:

Sensitivity 88%

Specificity 89%

ACC 2002, presentation 1054-20

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0 20 40 60 80 100 12040

60

80

100

120

140

Frame no.

Intra

-cor

onar

ypr

essu

re [m

mH

g]In vivo elastography

Strain [%]

1.0

0.0

Eur Heart J 23(5): 405-413 (2002)

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Cross-section LAD of patient with U.A.P

Strain [%]2.0

0.0

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IVUS elastography before atherectomy

Strain [%]1.0

0.0

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Fibrous cap tissue

Fibro-fatty core tissue

Histology atherectomy specimen

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Echogram and elastogram obtained in vivo in Yucatanstrain

1%

0%

Elastic-von Giesson Picro-Sirius red Acid PhosphatasePolarized light

Circulation (2002) in press

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Tissue mean std

Normal segments (n=6) 0.21 0.09

Early fatty lesion (n=9) 0.46 0.17

Early fibrous lesion (n=3) 0.24 0.03

Advanced fibrous lesion (n=6) 0.22 0.04

Strain [%]

*

Strain and plaque composition in Yucatan

Univariate ANOVA on strain

Fat p=0.007M p=0.966

1 - Specificity

1.00.75.50.250.00

Sen

sitiv

ity

1.00

.75

.50

.25

0.00

Area=0.952

Circulation (2002) in press

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3 Dimensional Elastography

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Conclusion

Intravascular Ultrasound Elastography: A powerful technique to identify

the vulnerable plaque.