Chronic Total Occlusion Interventions

Techniques and Complications

Reginald Low M.D.University of California, Davis

Sacramento, California

Disclosure

• Consultant and Fellowship Support• Cordis J&J• Boston Scientific• Medtronic• FlowCardia

Patient SG - 4-3-08

• 41 y.o. male with history of meth use and hypertension

• Admitted with chest pain and shortness of breath

Introduction

• Recanalization of a Chronic Total Occlusion - The Final Frontier• Technically the most challenging coronary intervention• Difficult to Treat

• Time intensive• Significant contrast load• Significant radiation exposure• Complications

• Dissection, Perforation, Guide injury, Embolization, Myocardial Infarction, Death

• Usual Success rate ~ 50%• Commitment to CTO’s - Success rates now 60 - 90%

• Systematic approach• New technical advances

Background

• Definition - Chronic Total Occlusion• Lumen narrowing - Atherosclerotic occlusion• Antegrade flow - none• Duration - > 3 months (true Chronic)

• Prevalence -• Unknown in general population• Suspected CAD patients undergoing angiography

• 33% have CTO - 46% suitable for PCI1

• NHLBI Registry -• RCA occlusion most common, followed by LAD• Increases with age

1. Kahn JK, AHJ 1993

<65 65 - 79 >79 p

RCA 18.2 21.3 22.8 <.05

<.001

ns

LAD 13.8 19.1 21.5

LCX 11.0 13.2 12.7

Anatomy and Histopathology

• Thrombotic occlusion, thrombus organization & tissue aging• Histologically one-half of CTOs are <99% stenotic• No relationship between severity of histopathic lumen stenosis and

plaque composition or lesion age• Atherosclerotic plaque of CTO

• Intra and extracellular lipid• Smooth muscle cells• Extracellular matrix (predominate type I and III) in fibrous stroma• Calcium• Dense concentration of collagen rich fibrous tissue at proximal and

distal ends - columnlike lesion of calcified fibrous tissue

Large - 59% of all CTO

Small - 41% of all CTO

Comparison of CTO TissuesDifferential Elastance of Adventitia and Fibrous Plaque

Emery et al. LuMend, Inc.

Adventitia

Plaque

Rationale for CTO Revascularization

• Improve symptoms

• Improve coronary blood flow - O2 Supply

• Increase long-term survival

• Improve left ventricular function

• Improve electrical stability of myocardium - reduce predisposition for arrhythmic event

• Increase tolerance of progressive coronary artery disease - provide collaterals

TOAST-GISE

12 - Month Clinical Outcome

Olivari JACC 2003

CTO Success(n = 286)

CTO Failure(n = 83)

pValue

All deaths 1% (3) 3.6% (3) 0.130

Cardiac death 0.35% (1) 3.6% (3) 0.037

Nonfatal MI 0.7% (2) 3.6% (3) 0.077

CABG 2.45% (7) 15.7% (13) <0.0001

PCI, TLR 9.44% (27) 8.43% (7) 0.834

Any TLR 11.5% (33) 22.9% (19) 0.012

Any PCI 13.3% (38) 10.8% (9) 0.584

Any MACE 12.2% (35) 25.3% (21) 0.005

Predictors of Success

• Predictors of lower success• Increasing age of lesion - chronicity• Longer length of occlusion• Non-tapered stump• Origin of side branch at occlusion• ? Bridging collaterals

• 433 patients CTO’s1

• 25% Bridging collaterals• PCI success - 83 vs 75% p - ns

• Likely older lesion• Stiffer wires, tapered tips

1 Kinoshita I, JACC 1995;26:409

Chronic Total Occlusions

• Strategy and Technology• Guidewire

• Device• Micro Blunt Dissection (Frontrunner - Lumend)• Excimer Laser (Spectranetics)• Radiofrequency (Safe-Cross - ILT)• Vibrational (Crosser - FlowCardia)

Guidewires

Polymer cover with Hydrocoat hydrophilic coating

Intermediate coils: Maintain .014" diameter for smooth device delivery Hydrophobic or Hydrophilic coating for tracking

BMW

Intermediate section has both a hydrophilic coating and a polymer cover

BMW Universal

Whisper

Miraclebro 3

Tip feel and torque, 11 cm radiopacity, hydrophobic coating for tactile feel

Specialty CTO Asahi Wires

ASAHI CONFIANZA™ 9Tapered Tip

ASAHI CONFIANZA PRO™ 9

ASAHI CONFIANZA PRO™ 12

ASAHI MIRACLEBROS™ 3Straight Tip

ASAHI MIRACLEBROS™ 4.5

ASAHI MIRACLEBROS™ 6

ASAHI MIRACLEBROS™ 12

Torque response, drilling, anti-trap Interrogate lesion - transmits lesion information

Incr

easi

ng S

uppo

rt

Guidewires

Suzuki, Takahiko - CTO Summit 2007 Lubicity PenetrationTip Stiffness

Test Method

GW

Electronic Balance

10 mm

• Tip load value, (tip stiffness) gives a numeric value to the tip. It may help in determining the next wire choice, if the initial wire tip did not cross the (difficult) lesion

• The buckling load is defined as tip load

• The distance from the lower end of the pipe to the upper side of the electronic balance is 10mm

• Keep in mind, tip load only measures how much force it takes to “buckle” the tip of the wire

Guidewire Technique

• Optimal view - Quality imaging chain - Orthogonal View

• Contralateral injection - must see distal vessel

• Anticoagulation- Heparin, no GP IIb/IIIa

• Guide selection

• Generally 7 or 8 french

• Minimize curves to maintain tactile feedback

• Support can be acquired - active guide, deep intubation

• Change guide with 0.014 wire across using 0.035 wire in cusp

• Change guide with balloon fixed in guide extended 3-5 cm beyond guide tip

• Balloon anchor technique - balloon in proximal side branch

Guidewire Technique

• Support catheter• Good lumen for tactile feedback• Balloon catheter - Maverick 2.0 OTW• Transit, Quick Cross or Excelsior

• Drilling technique• Probe with soft wire • Specialty wire - Miraclebro 3• Stiffer wire - Miraclebro 6• Stiffer wire - Miraclebro 12• Penetrating wire - Confianza Pro• Polymer sleeve hydrophilic wire - PT graphix

• Penetrating technique• Confianza

Penetrating StrategyStiff Wire

Confianza Pro

Confianza Pro

Feather Touch Forceful

Drilling StrategySoft Wire

Hyperflex

CTO WireMiracleBros 3

Stiffer WireMiracle Bros 6

Very Stiff Wire

ConfianzaStepwise Increase Force

Guidewire Technique

• Wire selection

Hydrophilic (slippery) wire tip has difficulty engaging entry point dimple

Low lubricity (spring coil) wireTip can more easily engage entry point dimple

• Tip curve should be just larger than lumen diameter

• CTO lumen diameter is 0 mm - Wire tip curve should be near 0

Reentry into true lumenPenetrating in CTO fibrous cap

Remodeling

Immediate 6 Months

Guidewire Technique

• False lumen alternatives• Parallel wire technique

• Leave wire in false lumen• Second stiffer wire with OTW

catheter

• See saw technique• 2 OTW catheters

Guidewire Technique

• Reentry

• Crossing• Balloon - OTW otherwise Maverick 1.5 mm Monorail• Tornus

Small False Lumen

Easier to re-enter

Large False Lumen

More difficult to re-enter

• Eight (8) individual wires (.007") stranded together to form the catheter• Made of stainless steel for extra support strength• Silicone coating on inner/outer surfaces• 2.1 French or 2.6 French• To Advance - Counter-Clockwise rotation with the right hand while the left hand is advancing the device• If resistance is felt at the distal tip, do not exceed 20 rotations

Sub-intimal Tracking and Re-entry (STAR) Technique

• Failed CTO with Conventional Techniques - Wires and or Device Therapy

• Create a sub-intimal dissection plane with hydrophilic wire (Whisper or Pilot)

• Re-enter distally with wire usually at bifurcation• Similar technique to Peripheral CTO

Columbo CCI 2005

• Angiographic FU 21• No restenosis 48%• Non occlusive restenosis 29%• Occlusive restenosis 24%

IVUS Guided CTO Technique

• Reserved for failed CTO attempt with large dissection• IVUS in false lumen to guide entry of wire into CTO fibrous cap

Garcia PCR 2005

IVUS Guided CTO Technique

True lumen

False lumen

IVUS

Garcia PCR 2005

Retrograde Technique

• Collateral Channel• Bypass graft• Epicardial collateral• Septal perforator

• Technique• Retrograde wire crossing• Kissing wire technique• Knuckle wire technique• CART technique

• Controlled Antegrade and Retrograde subintimal Tracking

Tsuchikane, Etsuo - CTO Summit 2007

CTO - Restenosis & ReocclusionStent vs PTCA

32 28 32 32

5542

22 2231

74

5768 64

70 71

33

62 63

0

20

40

60

80

SICCO Mori

GISSOC

SPACTO

TOSCA

STOP

PRISON

SARECCO

Pooled

Stent PTCA

Restenosis

Reocclusion

127 8

3

118 8

2

8

26

11

34

2420

17

7

14

27

0

10

20

30

40

SICCO

Mori

GISSOC

SPACTO

TOSCA

STOP

PRISON

SARECCO

Pooled

Drug Eluting Stents for CTO

0

10

20

30

40

50

Average BMS

Research2004

Nakamura2005

Werner 2004

Serruys 2004

Colombo2005

Grube 2005

n = 340 n = 35

Cypher

n = 38

Taxus

n = 122

Cypher

n = 33

Cypher

n = 48

Taxus

n = 60

Cypher

Complications

CTOAngioplasty(n=2007)

Non-CTOAngioplasty

(n=2007) P

Death 1.3% 0.8% 0.13

Q-wave myocardial infarction 0.5% 0.6% 0.67

Non-Q wave myocardial infarction 1.9% 2.4% 0.27

Urgent bypass graft surgery 0.7% 1.1% 0.25

Urgent repeat PCI 1.5% 2.0% 0.23

Major adverse cardiac events 3.8% 3.7% 0.39

Stroke 0.01% 0.1% 0.63

Vascular complication 1.7% 2.5% 0.80

Suero JA JACC 2001;38:409

Complications

• Death and MI• Shearing off collateral circulation• Injure proximal vessel or side

branch• Perforation• Air embolism• Thrombus • Arrhythmia

• Emergency CABG• Proximal vessel injury or side

branch• Guidewire fracture or entrapment• Perforation• Subacute vessel closure

• Contrast nephropathy• Radiation skin injury

TOAST-GISE

376 patients (390 Occlusions) 29 Centers

Technical success 77.2% (301)

Procedural success 73.3% (286)

Death 0.26% (1)

Q wave MI 0.26% (1)

Non Q wave MI 4.3% (16)

Urgent CABG 0.53% (2)

Urgent repeat PCI 0.53% (2)

CVA 0

Perforation 2.1% (8)

In-hospital MACE 5.1% (19)

Olivari JACC 2003

Complications

• Major Complications• Death 0.8%• Emergency CABG 0.3%• Q wave MI 0.2%

• Minor Complications• Tamponade 1.1%• Aortic Dissection 0.4%• Acute Occlusion 0.8%• Subacute Occlusion 0.4%• Side branch compromise 2.6%• Coronary perforation

• Type I 9.0%• Type II 1.1%

Toyohashi Heart Center - CTO Summit 2007

Frontrunner

Adventitia

Fibro-calcific CTO

Similar to Ultrasound, but– Uses near- infrared light instead

of sound to create 10X better resolution (10 - 15 micron)

– Forward looking to offer guidance capability

Radio Frequency– Controlled RF energy to

effectively cross CTO’s

Detector

Safe-Cross Console and DisplayOptical Coherence Reflectometry (OCR)

Display

RF Unit

CrossingWire

SupportCatheter

OCR Unit

OCR Waveform Displays

No artery wall detected Artery wall detected No artery wall detected

The CROSSER™ SystemHigh Frequency Mechanical Recanalization Technology

The Electronics– The Generator provides high frequency current– The Transducer converts high frequency current → vibrational energy

The Catheter– The Energy is transmitted to the the tip of the CROSSER Catheter– 1.1mm tip with Hydrophilic Coating– Monorail and OTW– .014” guidewire compatible– 6Fr guide catheter compatible

TRANSDUCERPIEZOELECTRIC CRYSTALS

DISPLACEMENT

HORN

The CROSSER™ SystemHigh Frequency Mechanical Recanalization Technology

European Clinical Trial - Siegburg, Milan, Zurich

– Feasibility phase completed - 30 pts– Pivotal phase completed - 67 pts

64.2% success - no perforationsU.S. Clinical Trial - FlowCardia’s Approach to Chronic Total Occlusion Recanalization

– Feasibility phase - 45 pts– Pivotal Phase - 120 pts – 65% success - no perforations

Safe - No serious adverse events or perforations (208 cases)Quick - Average CROSSER time = 3:00 minutes

Amount of Contrast Used340.9 cc (48, 1065)

Total Procedure Time107.7 min (22, 315)

Total Fluoro Time43.8 min (5.7, 140.7)

In Hospital MACE: 4.8% (6/125)

Non-Q-Wave MI: 3% (4/125)>2xCK

Emergent CABG*: 0.8% (1/125)

Urgent CABG: 0.8% (1/125)

*Emergent CABG due to vessel rupture following stent implantation

CTO Device Therapy

Device PatientsInitial

attempt guidewire

Success

SpectraneticsLaser Wire

179 ? 61%

IntraLuminal SafeCross

107 10 min 54 -67%

Lumen (Cordis)Frontrunner

116 10 min 56%

FlowCardiaCrosser

72 10 min 65%

BridgePoint Medical

• Reentry Device• Guidewire in false lumen beyond CTO• Advance Flat balloon beyond CTO • Self orients parallel to adventitia• Deflect tip toward lumen• Advance wire into lumen

Summary

• Successful PCI of Chronic Total Occlusion may• Relieve symptoms• Improve LV function• Improve survival• Improve electrical stability• Enhance tolerance for progressive CAD

• Assess Risk / Benefit for each patient• Consider clinical, angiographic and technical factors

• Essentials of a CTO program• Knowledge of histopathology• Equipment knowledge and selection• Techniques - Guidewire, parallel wire, side branch, retrograde, STAR etc.• Specialty devices - Tornus, Frontrunner, Safe-cross, Crosser etc.• High resolution imaging, contra-lateral injection, orthogonal views• Operator, patient, staff, scheduling commitment to CTO program