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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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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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Classification of Restenosis (Mehran et al. Circulation 1999;100:1872-8)

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Incidence of DES ISR

5-6%

11-12%

6-7%

0%

2%

4%

6%

8%

10%

12%

Native Denovo Lesion 1st Gen DES

Real Life Patients 1st Gen DES

Real Life Patients 2nd Gen DES

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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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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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Definitions and Classification of Restenosis and Stent Thrombosis

Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907

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Possible Mechanisms of Restenosis After DES Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907

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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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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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Mechanical Factors (Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907)

Stent Under expansion

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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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Technical Factors • ‘Geographical Miss’ • Uncovered atherosclerotic plaque

• Baro trauma outside stented segment

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Technical Factors • Stent Gap

• Gap between two overlapping stents

• Bends and Curves

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Predictors of ISR or TLR After DES Implantation Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907

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Risk Scoring to Predict TLR in DES (Stolker et al. Circ Cardiovasc Interv. 2010;3:327-334)

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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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Morphologic Pattern of SES, PES, and BMS ISR Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907

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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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Morphological Pattern of Restenosis as a Predictor of Repeat ISR after DES ISR Treatment

(Dangas et al. JACC 2010; 56: 1897-907)

18%

57%

10%

23%

0%

10%

20%

30%

40%

50%

60%

Focal ISR Non Focal ISR

Repeat ISR TLR

DES ISR

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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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Algorithm for the Treatment of DES Restenosis Dangas et al. J Am Coll Cardiol. 2010;56(23):1897-1907

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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.