Drug-eluting Stent eluting Stent Drug eluting Stent lf Platform

DrugDrug--eluting Stenteluting StentDrugDrug eluting Stent eluting Stent

l fl fPlatformPlatform( )( )(Stent Material, Design, Mechanics)(Stent Material, Design, Mechanics)

최최 락락 경경최최 락락 경경

Buchen Sejong Hospital, Korea Buchen Sejong Hospital, Korea

Sejong General HospitalSejong General Hospital

History of StentingHistory of Stenting1985

1994FDA approval of 19691912 1985

Balloon mounted stainless steel graft implanted in canine aorta & peripheral

l

ppcoronary stents;

STRESS & BENESTENTshow reduced

1999First drug eluting stent implanted in

humans

1969Non-surgical endovascular

placement of guide wire mounted spiral

1912Paraffin-coated glass & metal

tubes implanted in canine thoracic vessels restenosis with

stenting vs. PTCA

springscanine thoracic

aorta

1964 1983 1986 1998 20061964Silicone elastomer

endovascular splint; Dotter & Judkins

propose concept of

1983Nitinol coils

implanted in canine peripheral vessels

1986First human

coronary stent implanted;

Self-expanding

1998EPISTENT shows

significant benefit of ReoPro® with stenting

2006First fully

bioabsorbable drug eluting stent

implanted in humansp p pstents

Self expanding stainless steel wire mesh implanted in canine coronary

arteries


Current commercially available DES

2002 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015

Metal &

TAXUS™

Element™Endeavor™

TAXUS™

Liberté™

Stent

Metal & Polymer

Bioabsorbablestents

ElementStent

PROMUS™

Element™

Stent

Stent

XIENCE™ V Stent

Sirolimus-eluting Cypher stent

TAXUS™

Express™

Stent

StentStent

XIENCE™ Prime Stent

everolimus-eluting PLLA stent (BVS)

tyrosine-

Genous EPC capture stent

NoboriCypher select

stent

PROMUS™ Stent

NEVO™ Stent

tyrosine-derived polycarbonateREVA stent

Biomatrix

Axxess Plus stent

X NX

2nd Generation Cobalt Chromium, Platinum Chromium Alloy

Bioabsorbable Polymer

Fully Bioabsorbable

Metal & Polymer1st Generation Stainless Steel

PROMUS Stent Xtent custom NX stent


Design criteria for the IdealDesign criteria for the Ideal DES

Biofunctionality Biocompatibility

Sejong General HospitalSejong General HospitalAm J Cardiol 2007;100[suppl]:3M–9M)

C diti f th Id l l tf t i lConditions of the Ideal platform material

Deliverability : ↑

Radial strength : ↑

Stent recoil : ↓ Stent recoil : ↓

Foreshortening : ↓

Scaffolding : uniform

Radio-opaque : ↑

Th b i i ↓


Thrombogenicity : ↓

M l d i d iMetals used in stent designs

• Stainless Steel - iron based alloys, 1st generation DESs

• Nitinol(Nickel + Titanium) self expanding shape memory• Nitinol(Nickel + Titanium) - self expanding, shape memory

- low thrombogenicity, Radius stentstent

- guidewire

C b lt Ch i 2 d i DES f• Cobalt Chromium - 2nd generation DESs, safe

• Tantalum, Platinum, Gold - good radiopacity, marker for stents

• Platinum Chromium - new generation DESs

• Magnesium alloy - biodegradable low strength


• Magnesium alloy - biodegradable, low strength

Typical values for conventional stent materials


Biomaterials. 2010 May;31(14):3755-61.

Mechanical properties of stent materials

Platinum

Chromium(PtCr)Chromium(PtCr)


N i l M l C i iNominal Metal Composition

PROMUS™ Element™ Stent

Coroflex® Please

Cypher Neo

PicoElite stentCoroflex® Please

Nobori™ stent

Biomatrix stent

Genous® R stent

Costar stent


Genous® R stent

Approach to Stent MaterialsApproach to Stent Materials

New Alloy Technology

Superb Deliverability

Thin Struts, low profiles

Excellent Clinical Results

Superb Deliverability


Excellent Clinical Results

basic terms andbasic terms and

designs of stents


Connecting Li kLink

Crests

C llCell

El L hRing

Element Lengthg


Element LengthElement LengthShorter Widero te

· Better scaffolding

· Higher radial strength• Poorer scaffolding

• Lower radial owe ad astrength


Element Length

Inconsistent Consistentelement length

Consistent element length

(EXPRESS)(ML VISION)


C RiCrests per RingL C t M CLess Crests Less Scaffolding less profiles

More Crests

More Scaffoldingless profiles

Less Expansion Range

1 12

2

3343

454


4 6

Connections per RingConnections per RingLess MoreLess

More Flexible

Less Scaffolding

More

Less Flexible

More Scaffoldingg More Scaffolding


C i iConnection Design

Si l d li k(ML VISION) Welded (ENDEAVOR)Single-curved link(ML VISION) Welded (ENDEAVOR)

Double-curved linkStraight link


(TAXUS) (CYPHER)

Fl ibilit & C f bilitFlexibility & Conformability

Crimped stent: flexibilityMore Less

E d d f bili


Expanded stent: conformability

Stent Pattern

Out of PhaseIn Phase (repeating)

Stent Pattern

Out of PhaseIn Phase (repeating)•Better Scaffolding •Less metal volume

1 2 3 4 5 1 2 3 4 5


S7 (out of phase)ZETA (in phase)

I Ph O t f PhIn Phase vs. Out of Phase

In Phase 14 rings (18 mm stent)In Phase 14 rings (18 mm stent)

Out of phase 8 rings (18 mm stent)


R di itRadiopacity

Visibility of the stent using fluoroscopy

Impacted by strut thickness / or stent material / alloyImpacted by strut thickness / or stent material / alloy


Strut Thickness

Thinner

Less Visible

Thicker

More Visible

Less Metal in the Vessel

Less stress to vessel walls

L di l t th

More Metal in the Vessel

More stress to vessel walls

M r r di l tr thLess radial strength More radial strength


Tubular vs. Coil-type stents

Stent deployment pressure: CS < TS

Elastic recoil: CS > TS

Radial strength: CS < TS

Stent shortening: CS < TS Stent shortening: CS < TS

Stent metal coverage area: CS < TS

Flexibility: TS < CS


Stent configurationStent configuration

Closed-cell stent designs

Advantages - more uniformity of drug deliveryAdvantages more uniformity of drug delivery

Disadvantages - less conformability, and deliverability(CYPHER)

Open-cell stent designs

Advantages-good trackability, delivery, and conformability

- better access to side branches

Di dDisadvantages - inhomogeneous drug delivery


(Driver™ Stent)

Mechanical propertiesMechanical properties of stentsof stents


St t ilStent recoil

a

b

c

d


Post Expansion Stent Diameter RecoilPercentage the stent diameter decreases after balloon deflationPercentage the stent diameter decreases after balloon deflation

62 5 St t P d t

5.0 4.9 4.7

4

5

ecoil

2.5mm Stent Products

3.03.0 3.0

2

3

ent

(%)

Re

0

1Perc

Xience V™ Endeavor™ Xience PRIME™ Cypher™ TAXUS™ Element™

TAXUS™ Liberté™

Endeavor™ Xience PRIME™ Xience V™ Cypher™ Promus™ Element™ TAXUS™ Liberté™


Stent Recoil3 0mm Stent Products

5 0

6.03.0mm Stent Products

4.0

5.0

o(%) .

2 0

3.0

oill ratio

1.0

2.0

Rec

0.0C yph e r

S e le c t+

T axu s

L ibe rte

E n de avo r X ie n c e V N o bo ri B io M atrix


Stent Shortening3 0mm Stent Products

2.0


1.5

(%) .

1.0

hortning

0.5

Stent sh

0.0C ypher T axus E ndeavor X ience V N obori B ioM atrix

S


S elect+ Liberte

R di l St thRadial StrengthAmount of Radial Force Required to Reduce the Diameter of a Deployed Stent

0 30 2 5mm Stent Products

0.240.26

0 20

0.25

0.30

Better

)


0.110.140.15

0.17

0 10

0.15

0.20

dia

l Forc

e

tons /

mm

)

0.00

0.05

0.10

Rad

(New

0.00TAXUS™

Element™TAXUS™ Liberté

™Cypher™ Endeavor™ Xience Prime™ Xience V™

PROMUS™ Element™ TAXUS™ Liberté™ Cypher™ Xience PRIME™ Endeavor™ Xience V™


R di l St thRadial Strength3 0 St t P d t


15

20

cm) .

10

15

orce(N

/c

5

Radial Fo

0C y p h e r

S l

T a x u s

L ib

E n d e a v o r X ie n c e V N o b o ri B io M a trix

R


S e le c t+ L ib e rte

C f biliConformability

1.20

Measures the ability of the stent to naturally conform to the vessel

1.01

0.80

1.00

ability

.mm

) Better

2.50mm product tested.

0.320.360.40

0.60

Confo

rma

(New

tons

0.040.060.09

0.00

0.20

Cypher™ Xience PRIME™ Xience V™ TAXUS™ Liberté Endeavor™ TAXUS™ Element™

Cypher™ Xience PRIME™ Xience V™ TAXUS™ Liberté™ Endeavor™Promus™ ™Promus™

Element™


St t D i SStent Design SummaryI S ff ldi : Profiles:Improve Scaffolding: In phase pattern More crests per ring

Profiles:

Thinner struts

Less crests per ring Shorter element length More connections per ring

p g

Improve Flexibility: Shorter element length Less connections per ring

Expansion Range:

More crests per ringLess connections per ring

Shaped or staggered connections

Metal in Vessel:

Thicker struts

Visibility: Thicker struts

More crests

Shorter element length


Optimal stent delivery systemOptimal stent delivery system

Trackability

Crossability Crossability

Pushability

Flexibility


Trackability Combined property

Stiffness and profile of the stent delivery system

Friction effects (system and GC&GW)

Proximal force (force-distance curve)


Crossability testThe ability of the distal part of the stent System to pass through a narrowed vessel lesion


St i d l f thStenosis model for the pushability testpushability test

The possibility to transmit a proximal push force to the distal part of the stent System


System FlexibilitySystem Flexibility Test method

nush d

ow

nFixation of Stent & Catheter (balloon)

7

Pu

t t

7mm

1 2

1 5

) .

stent

System : 3.0mm

6

9

m Flexibility(gf)

0

3

C y p h e r

S e l e c t +

T a x u s

L i b e r t e

E n d e a v o r X i e n c e V N o b o r i B i o M a t r i x

Syste

m


S e l e c t L i b e r t e

Measuring “Force” required to push 0.5mm down (bend)

The mechanical response of coronary stent

systemssystems

(3.0-mm,14 to 18 mm)

Sejong General HospitalSejong General HospitalCatheterization and Cardiovascular Interventions 73:350–360 (2009)

S f i t f f lSummary of requirement for successful treatment of coronary disease by stents


Acute clinical outcome

Tortuous lesions : conformable and flexible stents

Ostial lesions : t t ith t di l t Ostial lesions : stents with strong radial support

and good radiological visibility

Bifurcational lesions : Bifurcational lesions :

Ch i t t l l i : Chronic total occlusions :good lesion coverage and favorable radial

supportpp

Small vessels : stents with good flexibility, very

thin strut structure, and good stent


, gtrackability

St t ll iStent cell size : an important parameter when stenting bifurcation lesions

3 0mm stent3.0mm stent


The size of the ostium depends on the bifurcation angle and the side and main branch diameters


s2s3

슬라이드 43

s2 sejong, 2010-03-20

s3 sejong, 2010-03-20

The ostium circumference of a 3mm parent vesselof a 3mm parent vessel


Stent cell requirements forStent cell requirements for different stenting istrategies

Provisional bifurcation stenting:Provisional bifurcation stenting:

Stent cell size > side branch ostium

Crush stenting:

Stent cell size > side branch ostium

Culotte stenting:

Stent cell size > cross section of the


main branch

Long-term clinical outcome

Stent configuration

Strut thickness

Stent coating (Gold Tantalum coating Stent coating (Gold,Tantalum coating,

phosphorylcholine, carbon coating, and silicone carbide)

Drug-elution Drug elution


Percentage stenosis due to neointimal formation with different Multi-Link family stents


Multi Link family stents

Ann Ist Super Sanità 2007 | Vol. 43, No. 1: 89-100

Stent Design and Strut ThicknessStent Design and Strut Thickness (ISAR-STEREO-2 trial)

40%

31.4%30%

40%Thin Struts N=309Thick Struts N=302

50 microm

140 microm

21.9%

30%

tient

s

17.9%

12.3%

20%

% P

at

10%

0%Binary Restenosis

6 Month(P < 0.001)

TVR1 Year

(P < 0.001)


ACS RX Multi-Link stent (Guidant) vs. BX Velocity (Cordis)

C l iConclusions

Developing a better systematic understanding of mechanical properties of Stent andof mechanical properties of Stent and delivery system

1. help the selection of optimal instrumentation

2. markedly improve the technical operator’s

performance particularly in challenging casesperformance, particularly in challenging cases


Th kThank you forfor

youryour listening !g


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