Transcript BVS stent (Abbott Vascular)

Bioabsorbable stents: early
clinical results
Dr Angela Hoye MB ChB, PhD
Senior Lecturer in Cardiology
Hull & East Yorkshire Hospitals
MY CONFLICTS
OF INTEREST ARE:
Clinical Events Committee member for SPIRIT II, V
and SPIRIT Woman, fees paid by Abbott Vascular Inc
• Review the clinical evidence available
Historical studies
Igaki-Tamai
Current players
BVS
AMS
REVA
BTI, Ideal™, Elixir Medical, Orbus etc....
Future studies
Igaki-Tamai stent (Kyoto Medical Planning, Japan)
• Poly-L-lactic acid (PLLA) self-expanding stent
• Strut thickness of 170µm
• FIM study of 50 patients (63 lesions)
– 1 in-hospital stent thrombosis and Q-wave MI
– 1 non-cardiac death
– TLR (all with PCI): at 6 months
12%
at 12 months
17%
at 4 years
18%
– Late loss index (in the first 15 patients) was 0.48mm at 6 months
• Further studies in the SFA with this stent demonstrated
feasibility and safety in deployment of these stents over a length
of 70 mm – the stent has CE mark for use in PVD.
Tamai et al Circulation 2000;102(4):399-404; Tamai CCT 2004
Magnesium stent (AMS, Biotronik)
• Balloon-expandable magnesium alloy
absorbable stent
• The first clinical trial was performed in
20 patients with severe PVD with
disease in the proximal two-thirds of
one or more infrapopliteal arteries
• All were candidates for amputation and underwent PCI with the
magnesium stent on a compassionate basis
• Following pre-dilatation, the 3.0×15 and 3.5×15 mm AMS were
successfully deployed with good angiography and ultrasound results
• At 3 and 6 months post-implantation, the stent patency rates were
89% and 78%, respectively
• At 3 months, USS & MRI demonstrated complete AMS absorption
• At 6 months follow-up, only 1 patient required amputation
Magnesium stent (AMS, Biotronik)
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Coronary FIM multicentre study of 63 patients – PROGRESS-AMS
The primary endpoint was MACE at 4 months and ischemia-driven TLR
Safe: no death, no MI, no stent thrombosis
The stent was well-expanded on deployment with no immediate recoil
High restenosis rate with an in-stent late loss of 1.08 ± 0.49mm
Cumulative frequency curves of insegment luminal narrowing before,
immediately after and at 4 months followup after AMS
Ischaemia-driven TLR was 24%
at 4 months, and 45% at 1 year
Erbel et al Lancet 2007;369:1869-75
Waksman et al JACC Cardiovasc Interv. 2009 Apr;2(4):312-20
Magnesium stent (AMS, Biotronik)
• PROGRESS-AMS: results of IVUS
Erbel et al Lancet 2007;369:1869-75
Magnesium stent (AMS, Biotronik)
“Slower degradation is warranted to
provide sufficient radial force to improve
long-term patency rates of the AMS”
Prolong the mechanical stability in
order to retain the stent throughout
the period of proliferative response
(AMS-2)
A drug-coated version to try and
suppress neointimal hyperplasia
(DREAMS AMS-3)
Waksman et al JACC Cardiovasc Interv. 2009 Apr;2(4):312-20
Magnesium stent (AMS, Biotronik)
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Return of coronary vaso-reactivity following absorption
5 patients treated with AMS compared with 10 treated with metal stents
QCA was measured on two orthogonal views at 0.2mm intervals
throughout the stented segments and a 1cm proximal reference
segment before and after administration of 2mg intra-coronary ISDN
Ghimire et al Eurointervention 2008;4:481-4
REVA stent (Reva Medical)
• Polycarbonate tyrosine-derived stent which
breaks down to amino acids, alcohol, and
carbon dioxide. It is impregnated with
iodine to improve radio-opacity
• Balloon-expandable and has a ratchet-like
system so that as it expands the stent
ratchets open and can't reclose down
• Radial support for 6 months
• Stent absorption over 2 years
• Interim analysis of 27 FIM patients demonstrated “unfavourable
results between 4 and 6 months with higher than expected TLR
driven by reduced stent diameter”
Grube TCT 2008
REVA stent (Reva Medical)
OCT performed at 12 months demonstrated the presence of
neointimal tissue covering the entire treated segment, and signs of
stent absorption
REVA stent (Reva Medical)
• Second generation stent with sirolimus on the
abluminal surface
• Absorption time: 4 years
• Duration strength 4-6 months
• FIM due to start shortly
Pollman Eurointervention Suppl 2009,F54
BVS stent (Abbott Vascular)
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PLA backbone, releases everolimus (80% by 30 days)
Struts are 150µm, radiopaque markers at either end
ABSORB cohort A FIM trial
3x12 then 3x18mm BVS
Simple lesions
Ormiston et al Lancet 2008
Serruys et al Lancet 2009
BVS stent (Abbott Vascular)
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MACE rate was 3.4% (1 patient)
No “stent” thrombosis
In-”stent” late loss at 6 months was 0.43mm (0.47mm at 2 yrs)
Vessel and scaffold area changes:
Ormiston et al Lancet 2008
Serruys et al Lancet 2009
• Vasomotion study (n=7)
• Methergine (non-endothelial
dependent vasoconstrictor)
• Shows the vessel is no
longer “splinted”
• Comparison of a Cypher
stent and BVS on MSCT
• Allows non-invasive FU
with quantification
• Results of ABSORB Cohort A were encouraging with
only 1 MACE and resorption largely complete by 2 yrs
• The Cohort A scaffold had shrinkage at 6 months that
was the major contributor to the late loss
BVS 1.1
BVS 1.0
device
1.25
0.87
– Same strut material, thickness, drug (everolimus) and
resorption time
– More uniform strut distribution, vessel support and drug
application
BVS stent (Abbott Vascular)
• ABSORB Cohort B FIM trial
• 3.0x18mm BVS to treat lesions ≤14mm in length
BVS stent (Abbott Vascular): Cohort B FIM trial
30 days
N=101
6 months
N=101
Cardiac death (%)
0
0
MI (all non-Q-wave) (%)
2
3
Ischaemia-driven TLR (%)
0
2
PCI
0
2
CABG
0
0
MACE (%)
2
5
TLF (%)
2
5
No thrombosis by ARC or Protocol
MACE: cardiac death, MI, ischaemia-driven TLR
TLF: cardiac death, MI, ischaemia-driven TLR, ischemia-driven TVR
In-”stent” late loss of BMS / Xience V / BVS 1.0 / BVS 1.1
ABSORB: BVS 1.0
Δ Vessel Area
= +0.3%
Δ Stent Area
= -11.8%
Δ Lumen Area = -16.8%
NIH Area
% VO
(mm2)
= 0.29
= 5.3%
ABSORB: BVS 1.1
Δ Vessel Area
= +2.4%
Δ Stent Area
= -2.0%
Δ Lumen Area = -3.1%
NIH Area (mm2) = 0.08
% VO
= 1.2%
• Appears safe and effective
• Limitations: Markers difficult to see in large patients
– Not tested in more complex anatomy
– Should not re-introduce an undeployed stent as less
securely mounted
– Aggressive post-dilatation will cause strut fracture
Summary & conclusions
• Potential advantages of biodegradable stents:
– Shorter duration of dual anti-platelet therapy
– Recovery of endothelial function
– No remaining prosthesis therefore enabling future revascularization
without the increased MACE associated with treating an “in-stent
restenosis”; no “full metal jacket”
– Potential for applications such as angiogenesis and gene transfer
– Compatibility with non-invasive imaging modalities (CTA and MRI)
• The potential (long-term) advantages of biodegradable
stents have to be weighed up against the limitations:
– Lower strength compared to metallic stents → recoil
– Relatively poor crossing profile
– Radiolucent
Summary & conclusions
• However, we have learnt much from the early clinical
studies
– The importance of recoil and speed of stent absorption
– The advantage of combining with anti-proliferative drug-elution
• Future work will focus on optimising the trade-off
between stent deliverability, strut thickness, and
optimal drug-elution
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BVS testing in more complex disease
2nd generation REVA which is sirolimus-eluting
2nd generation AMS with drug-elution (DREAMS)
Elixir medical device (PLA sirolimus-eluting stent)
Biocorrodible iron stents
etc etc etc.......................