Les différents stents coronaires et les critères de sélectionvideos2.overcome.fr/.../jeudi/gauguin/09h00/finet.pdf · G. Finet et J. Ohayon (work in submission) 0 2 4 6 8 10 12

Gérard FINET MD PhD

Department of Cardiology and Interventional Cardiology

Cardiovascular Hospital - Hospices Civils de Lyon

INSERM Unit 886

Claude Bernard University Lyon 1

Lyon - France

XIVème Congrès Francophone de Cardiologie Interventionnelle - 2012

Les différents stents coronaires et les critères de sélection

[email protected]

Les plateformes des stents coronaires sont-elles identiques ?

Elles ne le sont pas.

Les critères decriptifs sont-ils nombreux ?

Oui.

Les critères descriptifs sont-ils univoques et indépendants ?

Non.

Notre choix sera-t-il ainsi le fruit d’un compromis ?

Oui.

Disposons-nous de toutes les données nécessaires à notre choix ?

Non.

Stent strut Three-dimensional stent design

Crossing profile (stent/balloon system)

Strut thickness

Geometry of strut cross-section

Strut width

Surface metal coverage

Global stent design (sinusoidal ring / homogeneity / connectors)

Flexibility (stent/balloon system)

Elastic recoil

Radial strength

Conformability (stent deployed)

Radio-opacity

Cell geometry & Maximum expanded diameter

Alloys



Strut thickness


Strut width




Elastic recoil

Radial strength


Radio-opacity


Alloys


Mechanical properties of stent

Strut thickness t

Strut width w

Strut radius r

F L

L F

w F

t F

r F

F = radial strength

Etave F, Finet G, et al. J of Biomechanics 2000

(Kpa)

Elastic zone plasticity

Elastic recoil



A316L L605 (Cr–Co)

Effects of different stent designs on local hemodynamics in stented arteries

Garasic JM et al. Circulation. 2000;101:812-818.

8 struts 200 mm 12 struts 200 mm and 125 mm

Thickness of Strut Randomized comparative trial of thin-strut bare metal stent

Randomized comparative trial of thin-strut bare metal cobalt chromium stent versus a sirolimus-eluting stent coronary revascularization

Ortolani P et al. Cather and Cardiovasc Interv 2007;69:790.

Vision : 80 mm strut thickness

Cypher : 140 mm strut thickness

Strut thickness

Vessel injury and neointimal proliferation

Schwartz RS et al. J Am Coll cardiol 1992;19:267-74.

Coronary stent symmetry and vascular injury determine experimental restenosis

Schulz C et al. Heart 2000;83:462.

Coronary stent symmetry and vascular injury determine experimental restenosis

Schulz C et al. Heart 2000;83:462.

Morphological Predictors of Restenosis After Coronary Stenting in Humans

Farb et al. Circulation 2002;105:2974-2980.


Hemodynamically Driven Stent Strut Design

Jimenez JM et al. Annals of Biomedical Engineering 2009; 37:1483.

Cross-sectional stent strut geometries



Streamlines in the foreground of a nondimensional pressure

Blood flow



Normal artery wall

Current commercial stent

a streamlined stent

Hemodynamically driven stent strut design

G. Finet et J. Ohayon (work in submission)

Edelman ER et al., Circulation 2011

90 microns

70

microns

Study of 8 strut geometries (G. Finet)

Strut geometries

Rectangular struts Circular struts Rectangular with round sides and Ellipsoidal struts

Results w = 110 µm h =100µm

w = 110 µm h =75µm

w = 110 µm h =50µm

w = 110 µm h =100µm

w = 110 µm h =75µm

w = 110 µm h =50µm

w = 110 µm h =90µm

h =70µm

Flow recirculation

distance (µm) 181 122 69 194 89 24 179 114

Low shear stress distance

(µm) 166 138 95 196 98 47 188 145


0

2

4

6

8

10

12

14

16

0,00 0,50 1,00 1,50 2,00 2,50 3,00 3,50

Wa

ll s

he

ar

str

es

s (

Pa

)

X (mm)

990-0

990-330

990-660

100 µm

330 µm

660 µm

330

100

660

660 µm

990 µm

Wall Shear Stress (Pa)


Overlapping and Malapposition of Stents (preliminary results)



Strut thickness


Strut width




Elastic recoil

Radial strength


Radio-opacity


Alloys

Longitudinal stent deformation Accidental mechanical compression

in Percutaneous Coronary Intervention

Hanratty CG, Walsh SJ. Longitudinal compression: a “new” complication with modern coronary stent platforms – a time to think beyond deliverability. EuroIntervention. Ahead of print articles Mortier P, De Beule M. Stent design back in the picture: an engineering perspective on longitudinal stent compression. EuroIntervention 2011;7:369-376. Williams PD, Mamas MM, Morgan K et al. Longitudinal stent deformation – a retrospective analysis of frequency and mechanisms. EuroIntervention 2011. Ahead of print articles Prabhu S, Schikorr T, Mahmoud T et al. Engineering Assessment of the Longitudinal Compression Behavior of Contemporary Coronary Stents. EuroIntervention 2011. Ahead of print articles

1- It is a stent longitudinal deformation by accidental compression, exceptionnally occuring during PCI (0.2% of cases) by conflict with an endovascular tools

2- This is a new mechanical stent complication

3- Occurring on new generation stent platforms

4- Possibly questioning the mechanical originality of the contemporary coronary stent designs (stent strut thickness, alloys, 3D stent design)

5- Appearing more often with the Promus Element stent®, an offset peak-to-peak stent design according to the specific classification of Prabhu et al. (Abbott Vascular) and responsible for a longitudinal deformation 4.7 times higher than the average of the deformations observed in the remaining 13 stents tested during a longitudinal compression force of 50 grams or approximately 0.5 N, which is a careful experimental work but with a clear conflict of interest.

We could try to summarize all of these publications:

(Finet G and Rioufol G. unpublished data)

Longitudinal deformation detected by angiography

1 2 3 4 5 6

1. Promus Element 2. Xience Prime 3. Resolute 4. Endeavor 5. Cypher Select 6. Biomatrix

Compression resistance of stent design configurations

Prabhu S et al. Engineering Assessment of the Longitudinal Compression Behavior of Contemporary Coronary Stents. EuroIntervention 2011. Ahead of print articles

Longitudinal stent compression… What lessons for our PCI ?

These studies have the great interest of collating and precisely describing 12 cases of longitudinal stent deformation by accidental longitudinal compression during PCI. The descriptive approach is exemplary, drawing attention to an exceptional event. It cannot, however, be said to be a novel phenomenon. In most cases, it is inextricably linked to the procedure as such. All scenarios must be anticipated so as to ensure against such events during intervention. To go beyond the precise analytic description of the 12 cases reported, specifically implicating a stent design with respect to its mechanical behavior remains in the present state of affairs entirely hypothetico-deductive as it is difficult to isolate a mechanical parameter without influencing on the global mechanical behavior of the stent.

Stent strut


Strut thickness


Strut width




Elastic recoil

Radial strength


Radio-opacity


Alloys

Longitudinal strength

Three-dimensional stent design

Before PCI

After PCI

Crossing profile (mm)

Strut thickness (mm)

Strut geometry

Strut width (mm)

Surface metal coverage (%)

Global design

Flexibility

Morphogramme radar

Elastic recoil (%)

Radial strength (N)

Conformability

XRay visiblity

Cell size (mm)

AO stent HCL 2011 – G. Finet & G. Rioufol

0

1

2

3

4

5

Crossing profile

Strut thick

Strut width

SMC

Elastic recoil

D Cell

3D mesh

Rxopacité

analyse morphogramme radar : STENT #1

Malapposition proximale Déstructuration après dilatation de la

branche collatérale

Stent #1

Stent #2

Taxus Liberte® (Boston)

Promus Element®

(Boston)

Cypher Select® (Cordis)

Endeavor® (Medtronic)

Resolute Integrity® (Medtronic)

Xience Prime®

(Abbott)

Biomatrix Sensor® (Biosensor)

(conception : G. Finet Réalisation : Société SEGULA - Technologies Sud-Etablissement, Saint-Priest, France).

Les dentelles du Cygne (Supernovae)

Documents

Les différents stents coronaires et les critères de sélectionvideos2.overcome.fr/.../jeudi/gauguin/09h00/finet.pdf · G. Finet et J. Ohayon (work in submission) 0 2 4 6 8 10 12