This document discusses restenosis (renarrowing of arteries) after percutaneous coronary intervention (PCI) procedures like balloon angioplasty and stent placement. It notes that drug-eluting stents have significantly reduced restenosis rates compared to bare metal stents. However, in-stent restenosis remains a problem, occurring in approximately 5-7% of patients within 1-2 years after PCI. The document examines factors that can influence restenosis risk like patient characteristics, lesion characteristics, technical aspects of the procedure, and properties of the stents. It also discusses challenges in treating in-stent restenosis when it does occur.

1. HEART INSTITUTE

2. Prediction of restenosis after PCI with
contemporary drug-eluting stents
DR. ASHOK SETH
FRCP (LOND), FRCP (EDIN), FRCP (IREL), FACC, FSCAI, FCSI, DSc.
CHAIRMAN
CHIEF OF CARDIOLOGY
CHAIRMAN – CARDIOLOGY COUNCIL, FORTIS GROUP OF HOSPITALS
FORTIS ESCORTS HEART INSTITUTE
PRESIDENT – CARDIOLOGICAL SOCIETY OF INDIA
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3. Restenosis After BA and Stent
• Most significant problem for years
• DES have dramatically reduced instent
restenosis.
• Low rates of ISR in DES still a problem.
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4. Classification of Restenosis
(Mehran et al. Circulation 1999;100:1872-8)
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5. Incidence of DES ISR
12% 11-12%
10%
8% 6-7%
6% 5-6%
4%
2%
0%
Native Denovo Real Life Patients Real Life Patients
Lesion 1st Gen DES 1st Gen DES 2nd Gen DES
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6. Delayed Restenosis
• Late ‘Catch Up’
Modest increase in NIH beyond 1-year on IVUS
study follow up.
– Delayed healing response
– Persistent biological reaction
– Hypersensitivity reaction to durable polymer
‘Therefore longer term follow up’
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7. Stent Thrombosis vs Restenosis
• ISR Presents as effort angina while stent
thrombosis usually presents MI.
• TVF within 30-days is usually stent thrombosis
while ISR is usually later.
• DES has delayed the time frame of ISR
• Both ISR and Stent thrombosis may co-exist.
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8. Definitions and Classification of Restenosis and
Stent Thrombosis
Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907
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9. Possible Mechanisms of Restenosis After DES
Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907
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10. Biologic Factors
• Drug Resistance
• Hyper sensitivity
– Allergy to Nickel / Molybdenum of 316 to stenosis
steel.
– RADAR STUDY (Research on Adverse Drug / Device
Adverse Reports) - Drug Hypersensitivity for DES.
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11. RADAR (Research on Adverse Drug Events
& Reports)
(Nebeker JR et al. J Am Coll Cardiol 2006;47:175-181)
• 5783 AE after DES
• 261 Hypersensitivity Reaction
• 17 DES cause of HS
• 4 Died of stent thrombosis between
4-18 months
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13. Mechanical Factors
(Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907)
Stent Under expansion
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14. Mechanical Factors
(Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907)
Stent Fracture
• Incidence: 2-8%
• Rigid closed cell stents,
overlapping stents, longer
stents, vessel tortuousity,
angulation and torsion
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15. Technical Factors
• ‘Geographical Miss’
• Uncovered atherosclerotic plaque
• Baro trauma outside stented segment
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16. Technical Factors
• Stent Gap
• Gap between two overlapping stents
• Bends and Curves
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17. Predictors of ISR or TLR After DES Implantation
Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907
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18. Risk Scoring to Predict TLR in DES
(Stolker et al. Circ Cardiovasc Interv. 2010;3:327-334)
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19. Predictors of DES Restenosis
(Corbett et al. Circulation. 2006;114:II_688)
• 2269 lesions 1283 patients (2003-2005)
• Angio FU 70% DES ISR : SES 16.9%
: PES 16.8%
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20. Morphologic Pattern of SES, PES, and BMS ISR
Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907
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21. Clinical and Angiographic Outcomes After Percutaneous
Treatment of DES ISR
Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907
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22. Morphological Pattern of Restenosis as a Predictor of Repeat
ISR after DES ISR Treatment
(Dangas et al. JACC 2010; 56: 1897-907)
Repeat ISR TLR
60% 57%
50%
40%
30%
23%
20% 18%
10%
10%
0%
Focal ISR Non Focal ISR
DES ISR
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23. Treatment of DES ISR
‘Difficult Disease Process’
• IVUS or other imaging essential to understand
the underlying mechanism.
• OPTIONS
– Balloon angioplasty
– DEB
– DES : Same DES
: Different DES
– VBT
– CABG
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24. Algorithm for the Treatment of DES Restenosis
Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907
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25. Conclusion
• Though DES has lowered the restenosis rates of PCI, the
increased complexity of lesions being treated has resulted in
DES ISR being an important problem.
• The predictors of restenosis in DES era are similar to the BMS
era, but DES ISR can occur later and tends to be more focal and
this has a better prognosis than BMS ISR.
• Diffuse DES ISR is a very ‘difficult animal’ as the pathophysiology
and causative mechanism of DES ISR are in many cases unclear
and hence treatment options are ‘hit and trial’.
• Further studies new DES and Bioresorbable stents are on the
way to overcome this important problem.
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