Repairing Coronary Arteries, pumpsandpipesmdhc
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Transcript of Repairing Coronary Arteries, pumpsandpipesmdhc
Repairing Coronary ArteriesRepairing Coronary Arteries
Neal KleimanDirector Cardiac Catheterization Laboratory
Methodist DeBakey Heart CenterProfessor of Medicine
Weill Medical College of Cornell University
Neal KleimanDirector Cardiac Catheterization Laboratory
Methodist DeBakey Heart CenterProfessor of Medicine
Weill Medical College of Cornell University
Courtesy of Dr. Paul Tierstein
Courtesy of Dr. Paul Tierstein
Angioplasty: The Thirtieth
Anniversary
Angioplasty: The Thirtieth
Anniversary
Gruntzig
Patient
Balloon Angioplasty: The Initial Concept
Balloon Angioplasty: The Initial Concept
“Footprints in the snow”
Mechanism of AngioplastyMechanism of Angioplasty
Landau C et al. N Engl J Med 1994;330:981-993
Angioplasty: Issues Seeking Solutions
Angioplasty: Issues Seeking Solutions
The atheromatous plaque is part of the arterial wall, not simply a harmful deposit on a normal structure
Blood vessels rarely follow linear courses The artery is reactive and blood is reactive!
– All intra-arterial procedures injure the wall and provoke scar formation (“restenosis”)
– Blood is a substance that when provoked, turns from a viscous fluid into a solid (clot)
How are these problems manifest following angioplasty?
How are these problems manifest following angioplasty?
Failed procedure: 5% (vessel just can’t be dilated)
Abrupt closure: 5% Periprocedural heart attack: 10% (3/4 of
these are very small) Renarrowing or restenosis: 30% - 40%,
particularly in long areas of blockage, and patients with diabetes.
Angioplasty – The major issue for the last thirty years
Angioplasty – The major issue for the last thirty years
How to modulate the vascular and blood reactivity to the barotrauma caused by balloon injury.– Preventing vascular smooth muscle cells from
forming “scars” inside blood vessels– Preventing platelets from forming clots on the
injured areas
Chung, I.-M. o et al. J Am Coll Cardiol 2002;40:2072-2081
Restenosis Or “Scar Formation” After Angioplasty – The Role Of Tissue Ingrowth
Why not Scoop out the plaque?Why not Scoop out the plaque?
DCA picture
Why not grind it up?Why not grind it up?
Why not vaporize it?Why not vaporize it?
316 L Stainless Steel 130-140 strut) or Co-Cr Alloy (80-90 strut)
Stents vs POBAStents vs POBA
Improved arterial lumen– Reduces recoil– Scaffolds tears and dissections
Reduces abrupt vessel closure Restenosis reduced from 40% 20% No documented reduction the rates of
death or heart attack
Drug Eluting StentsDrug Eluting Stents
Stent + Drug + Polymer The drug prevents cell replication by
interfering with cellular reproduction. Reduces in-stent renarrowing 20% <5%
and the need for repeat procedures In 2006, accounted for 90% of stent use in
the US and 30%-50% in Europe In 2007, use is approx 70% in US and
20% in Europe
Drug Eluting StentsDrug Eluting Stents
Polymer controls the release of drug at the appropriate rate (currently 2-4 weeks)
Strut separation and contact with the arterial wall influence the rate of drug delivery and possibly the clinical outcome.
The stent thus becomes both a scaffold and a platform
Paclitaxel Drug Eluting Stent System (Taxus)Paclitaxel Drug Eluting Stent System (Taxus)
Elastomeric, Polyolefin Derivate
Sirolimus Drug Eluting Stent System (Cypher)Sirolimus Drug Eluting Stent System (Cypher)
PBMA / EVA
Heterogeneity of Re-Endothelializaiton in a Drug-Eluting
Stent
Heterogeneity of Re-Endothelializaiton in a Drug-Eluting
Stent
Finn, Circulation: 2007
Cumulative Incidence of DES Thrombosis in the Rotterdam-Bern Registry
Cumulative Incidence of DES Thrombosis in the Rotterdam-Bern Registry
0.6%/year late thrombosis
Daemen: Lancet: 2007:369: 667
Accumulated early and midterm implantation experience
8,146 Patients initially 981 at f/u
24% of patients with thrombosis were on clopidogrel and aspirin
16 RCTs; 8,695 Patients
Follow-up to 4 Years
Reduced Risks of Re-intervention: HR = 0.74 (0.63-0.87) and
Stent Thrombosis: HR = 0.66 (.46-.94)
No in Risk of MI: HR = 0.84 (0.69-1.03)
16 RCTs; 8,695 Patients
Follow-up to 4 Years
Reduced Risks of Re-intervention: HR = 0.74 (0.63-0.87) and
Stent Thrombosis: HR = 0.66 (.46-.94)
No in Risk of MI: HR = 0.84 (0.69-1.03)
New Approaches to Stenting Coronary Arteries
New Approaches to Stenting Coronary Arteries
Thinner stent struts New polymers
– Phosphorylcholine (PC) – mimics the outer layer of a normal cell membrane
– Bioabsorbable polymers – elute the appropriate medication and then disappear
Bioabsorbable stents– Entire stent itself is reabsorbed over a period of six
months
Endothlial Precursor Cell (EPC) Capture
Innovations over time
0
10
20
30
40
POBA early POBA late Stent early Stent late DES
Even
t Rat
e %
1977 1985 19971994 2003-present
Evolution of PCI: The Dominant Coronary Revascularization Therapy
Evolution of PCI: The Dominant Coronary Revascularization Therapy
FailureEm CABGRestenosisStent thrombosisVLST
Dr. Don Baim, FDA Panel Meeting December 2006
Progressive improvements in success, safety, and durability, as serial new technologies have been launched.