Chronic total occlusion of coronary artery

Durga PavanNizam’s Institute of Medical Sciences, India

DEFINE

• >99% stenosed•Duration >3 months•TIMI 0-1

Histopathology

•Organized thrombus.•Fibrotic plaque•Calcified lesions.•Proximal/ distal fibrous cap•Micro channel in the occlusion segment

Micro channel inside the occlusion•Often extend to small side branch & to

adventitia

•Extravascular micro channels in early phase of occlusion

•More mature CTO –intravascular channels increase

•Matured CTO - both fewer•Longitudinal continuity – 85% of entire

length of CTO

Benefits of CTO-PCI▫Symptom relief, ▫Improvement in left ventricular function,▫Improve tolerance of a future acute

coronary syndrome▫Reduce the need for coronary artery

bypass graft surgery▫Better long-term survival.

Symptom relief

• TOAST-GISE (Total Occlusion An-gioplasty Study–Società Italiana di Cardiologia Invasiva) trial, CTO-PCI success - 86%, CTO-PCI failure - 70% ,

angina-free survival (p=0.008)

• Cheng et al. Demonstrated that 76% of patients with CTO who were treated with PCI experienced an improved angina classification, whereas 17% of patients who were not treated with PCI improved (p<0.05).

•A 3.8% to 8.4% absolute reduction in mortality was associated with successful versus failed CTO-PCI.

Survival advantage

•Symptoms▫A CTO with well developed collaterals is

hemodynamically similar to 90% coronary stenosis without collaterals – significant recovery of ventricular function is expected

•Viable myocardium▫Recovery of LV function depends on the presence

of hibernating viable myocardium•Success

▫If the likelihood of success is moderate to high (>60%) and the likelihood of complications less, PCI is encouraging.

Patient selection

Barriers

•Complications•Failure rates•Economic burden •CIN

Complications

•Impairment of collateral flow ▫spasm, shearing off side-branches and

collateral by dissection, distal embolization• Dissection with branch occlusion &

Perforation ▫intra-wall balloon expansion, side-branch

dilatation, damage of neochannels connecting vasa vasorum

•Guidewire entrapment•Subacute vessel reocclusion

▫8% of total occlusion within 24hr Vs. 1.8% of non total occlusion

•CIN•Radiation

Reasons

•Not able to cross guidewire – 63%•Long intimal dissection – 24%•Dye extravasation – 11%•Balloon did not cross or dilate – 2%•Thrombus – 1.2%

Kinoshita I, et al. JACC 1995;26:409-411

Predictors• Clinical-

▫Duration - >3-6 monthS▫CRF

• Angiographic ▫Calcification(at entry point/at distalcap)▫Blunt stump▫>45 angulation of target vessel▫Length of occlusion >15-20mm▫Vessel <3mm▫Multiple lesions in target art▫Lack of distal vessel filling▫Bridging collaterals and side branch

Predictors of success or failure in PCI of CTOPredictors of

successDuration < 3 monthsAntegrade flow +Tapered morphology

+Bridging collaterals – Side branch – lesion length < 15

mmSingle vessel disease

Predictors of failureDuration > 3 monthsAntegrade flow – Tapered morphology – Bridging collaterals + Side branch +, ostial

lesion lesion length > 15 mmMulti vessel diseaseVessel & lesion

tortuosity & calcification

Bridging collaterals are more common in lesions > 3 months old. Extensive bridging collaterals that form caput medusae around the occluded vessel are generally not suitable for PCI

Predictors of Procedural Success

TOAST - GISE

PROCEDURAL SUCCESS

Economic burden

•2 procedure•Fluoroscopy•Hardware more

4 angiographic parameters

•Location of the proximal cap using•Length•Side branches•Target vessel at the distal cap•Collaterals for retrograde techniques.

Two injection same time

•Collaterals to the distal target vessel.•Lesion length and the size and location of

the distal target vessel, evaluating whether there is a significant bifurcation at the distal cap, and for deciding on the optimal CTO PCI strategy

Collaterals Assessment

•CAG▫Visible collaterals of 0.3-0.5mm▫<100 micro m are not visualized▫Selective using micro catheters

Collaterals grade[Rentrop] 0 1 2 3

Visible filling of any collateral channel

Filling of the side branches of the occluded artery, with no dye reaching the epicardial segment

Partial filling of the epicardial vessel

Complete filling of the epicardial vessel by collaterals

Collaterals -Levine etal

▫Septal▫Intra arterial (bridging)▫Epicardial

Proximal take off Distal takeoff

Collaterals

Werner et al

•3 grades▫CC0-no continues connection▫CC1 - continuous , threadlike▫CC2 – continuous , small side branch like

CT angiogram

•Procedural success•Distal vessel •Collateral •Best angle for PCI approach

IVUS

•Entrance •Subintimal vs true lumen

Guide catheter• First key to success• For effective guide wire manipulation :

▫coaxial orientation of guide catheter important▫stability& back up force

• RCA - AL1/0.75 with side holes• Shepard crook RCA - AL1or2• Prox RCA lesion - JR ( avoid ostial damage)• LCA - Extra back up(XBU,EBU,)• LCX (short left main) - AL1 or2 (better support &

co-axial)

Guide catheter•7F or 8F guide catheter

▫Superior backup support (needed in CTO)▫Inter twining is less common while using

parallel wires▫Switching over to devices like rotablator is

easy▫Permit better contrast injection.So, radial approach is not preferred for CTO.

•Side hole guide catheter is useful for RCA▫Maintains perfusion to the sinus node artery &

conus branch

CTO wires

Fielder XT wire (Asahi Intec, Nagoya, Japan) and Run-through taper wire (Terumo Corporation, Tokyo,Japan)

▫ A hydrophilic and/or polymer-jacket ▫ 0.014-inch guide wire, ▫ Low gram-force▫ Tapered 0.009-inch tip

•Antegrade micro channel or soft tissue probing and also for knuckle techniques.

Fielder FC wire (Asahi Intecc) and Pilot 50 wire (Abbott Vascular,Santa Clara, California)

▫Polymer-jacket hydrophilic ▫Non tapered▫Low stiffness▫0.014-inch guide wire.

Pilot 200 guidewire (Abbott Vascular).

▫Polymer-jacket ▫Moderately high– gram-force (4 to 6 g),, ▫Non tapered ▫0.014-inch guide wire.

•For complex lesion crossing, long lesions, knuckle technique, and dissection/re-entry.

•Performs well in very tortuous segments with an ambiguous course

Confianza Pro 12 wire (Asahi Intecc).

▫High– gram-force▫Non jacketed tipped▫0.014inch guidewire,tapered 0.009-inch

guide wire.•Penetration techniques, cap puncture,

complex lesion crossing, and lumen reentry techniques.

•Best used when the vessel pathway and location target coronary segment are well understood.

Hydrophilic wires

• Slippery upon contact with blood

• Useful in lesions with visible channels.

• Excellent for markedly tortuous lesions

• Can easily find way in to a false lumen with less tactile feed back intimal dissection & proceedural failure or even perforation & tamponade

• They are less steerable

Asahi Fielder (Abott Vascular)

Asahi Prowater (Abott Vascular)

Whisper – Guidant Pilot – Guidant Shinobi – Cordis Choice PT (Boston

scientific)

Stiff guide wires

• Non hydrophilic coil tip designed to facilitate the penetration of distal or proximal cap.

• Stiff guide wires are particularly useful when proximal fibrous cap is hard. (esp. the tapered tip wires)

• Gradual step up approach using wires with increasing stiffness is useful.

• Cross-IT• Conquest• Miracle

Tapered tip

Tapered guide wire

•Technical success: 76%

•Success rate in visible micro channel

▫Incomplete micro-channel: 81%

▫Micro-channels with distal filling:

100%

Buettner HJ, et al. JACC

2002;39:30A

Micro catheters

•Wire exchange[floppy to dedicated stiffer]

•Torque to tip & improve feedback•Tip stiffness of guide wire

Corsair micro catheter (Asahi Intecc)

•2.7-F catheter with OTW hybrid catheter•Both micro catheter and support •Bidirectional wire braiding for torque

transmission, and an inner polymer lumen with soft tip for optimal wire control

•Cross collateral channels and provides the primary basis for conventional retrograde procedures.

•Super selective injection for collaterals•Antegrade direction for wire support.

The Corsair catheter is advanced by rotation in either direction. The Corsair should not be over-rotated (10 consecutive turns without release) as over-rotation could cause catheter kinking

Tornus micro catheter (Asahi Intecc)

• Braided-wire mesh OTW microcatheter with left-handed thread allowing for channel preparation and lesion crossing in resistant occlusions.

• Advanced using counterclockwise rotation and removed using clockwise rotation.

• Guidewire should remain within the Tornus inner lumen during manipulations, and over-rotation should be avoided to minimize the risk of kinking.

• Contrast injections should not be performed through the Tornus, as the contrast escapes through the wire braid.

Lesion crossing and lumen re-entry technologies•CrossBoss catheter (BridgePoint Medical,

Plymouth, Minnesota)•Stingray balloon and Stingray guidewire

systems (BridgePoint Medical).

Precautions▫Covered stents ▫Embolization coils ▫Pericardiocentesis trays▫Thrombectomy devices

STRATEGIES

Antegrade approachRetrograde approach

▫SINGLE WIRE▫DOUBLE WIRE

Parallel wiring Seesaw wiring Subintimal tracking and

reentry IVUS guided approach

Retrograde wire crossing

Kissing wire technique Knuckle wire technique CART Reverse CART

Next wire

•1. Floppy wire as the 1st wire •2. Intermediate or MIRACLE 3 •3. MIRACLE 6 •4. MIRACLE 12 or Conquest Family

Stepwise

•1.Atraumatic, tapered, hydrophilic FIELDER XT

•2.Stiffer, tapered wire like CONFIANZA9/ MIRACLE6

•3.Step down to softer wire

•Wire shaping

1ºbend of 30-45º1-2mm from tipFind softest part

2ºbend-10-15º@3-6mmWork as a navigator to orient tip

Tip curve should be just larger than lumen diameter

CTO, the lumen diameter = 0 mm

For CTO lesion – Guide wire-tip curve should be very small

Larger curve may hurt the vessel wall during direction control

Guide wire negotiation

•Different methods • Sliding AT

proximal cap • Drilling inside

CTO • Penetration Distal

cap • Micro channel tracking

•Simultaneous rotation & probing of lesion •High chance of entering to subintimal space ( tactile response - nil )

SLIDING

•Recent occlusion•Predominance of micro channels•Extremely low friction wires for picking micro channels used

• Recent total, subtotal occlusion ,ISR attempted with this strategy•Long duration – Micro channels replaced by fibrotic tissue

BEWARE bridging collaterals masquerading as microchannel

Polymer sleeved wires NOT forced against resistance, small tip bend, probing with mild rotation

Soft wires with polymer sleeve – Fielder series/ Whisper/ PT II

Drilling Strategy• If discrete entry point present

•Technique short curve(2mm) @45-60º to distal tip

sometimes a secondary curve given proximally

wire advanced with rapid rotational tip and gentle probing

start with MOD stiffness – progressive increase in stiffness

Entry to false lumen judged by tactile feel on pulling stiff wire•Reserved for the most skilled and experienced operator

•Ineffective with Blunt entry ,heavily calcific & resistant lesions

Penetration

•TechniquePushing stiff wire slowly& gradually – minimum rotation to target direction

Tapered tip wires Softer tip intially progressively stiffer wires Route determined – various angio or CT findings not by tactile feel

•Useful for blunt ,heavily calcific or resistant lesions

•Not for CTO with tortuous angulated or bridging collaterals because of higher chance of perforation

Drilling & penetration – guide support & tipload important

Tip load - success - chance of perforation

Penetration power = tipload/tiparea

• Tactile sensations▫ Feeling of the dimple at the entry point, especially in the abrupt type of CTO entry▫ Feeling of strong resistance when pulling back

the wire inside the CTO body, such as when the guide catheter is drawn into it—in this

situation, the wire tip has most likely migrated into the

subintima

▫ Feeling of no resistance the wire tip moves freely—this most likely means that the wire tip is either in the true lumen or in the extravascular space

Anchoring wire technique ▫Guiding catheter is unstable▫One wire is positioned in a prox side

branch▫Other wire for crossing of the occlusion

Anchoring wire

•Side branch protection▫Occlusion is long/ distal to side branch

•Correction of tortuousities▫Proximal tortuousities

•Buddy wire technique▫Facilitate passage of stent in complex

leisions▫Serves as rail

Double wire

•Parallel wire technique

1st wire in false channel

left in situ

2nd stiffer wire advanced parallel to first wire in same path

redirected to enter distal true lumen

main pitfall is wire twisting each other

Support catheter use, appropriate wire selection& handling –essential to avoid wire twisting

Main purpose : - redirecting a wire inside body of a cto & puncturing distal fibrous cap

Important prerequisite – distal vessel visualization

See-Saw Wiring

See-Saw Wiring

•Modification of parallel wire technique

•Uses 2 microcatheters or OTW baloons

•When first wire fails , 2nd wire with microcatheter or OTW baloon is inserted

•Risk – false lumen may enlarge – procedure failure

Side branch technique

Success• (1) Angle between direction in which the

wire lies and the bifurcating side branch is less than 90°;

• (2) Side branch less than 1mm; • (3) No diffuse plaque build-up about the true

lumen in the distal portion of the CTO • (4)True lumen to the ostium of the side

branch, the wire must be just to the side of the true lumen in the distal part of the CTO

Open sesame technique

•Hard plaque•Failed even with conquest pro 8-20•Side branch just in front of proximal cap•Pass stiff guide wire and/ or a balloon into

side branch.•Distortion of geometry•Enables guide wire to advance into true

lumen.

Dissection reentry techniques

•STAR -Uncontrolled•LAST - Somewhat controlled •Dedicated systems -Controlled

• Subintimal tracking and rentry technique

Used when attempts to recanalize true lumen failed

0.014 hydrophillic wire with J configration used(whisper,pilot)

Hydrophillic wire pushed through subintimal dissection plane

When pushed distal to occlusion J tip directed to truelumen

In an attempt to reenter

•Successful in those with previous attempt failed

•High chance of perforation

STAR Technique

Knuckle wire technique

•Polymer jacket wire (fielder XT or pilot-200)manipulated

• To create wire loop – advanced subintimally across CTO

•OTW system advanced to this area- rentry to true lumen with a stiffer wire or pilot 200

Cross Boss catheter

• Metal OTW micro catheter with rounded tip to prevent vessel exit

• Device rotated rapidly in either direction using fast spin

• Can advance through the CTO without a wire in the lead

• Subintimal position- true lumen reentry performed

• Smaller subadventitial space – less likely to accumulate blood

Sting ray balloon & guide wire system

1mm flat balloon with 3 exit ports connected to the same lumen

Distal exit port – for balloon positioning

Uses guide wire with extreme tapered tip (0.0025) for reentry

Distal true lumen entry confirmed by contralateral injection

RETROGRADE APPROACH

•Initially used after a failed antegrade approach

•Now used as initial strategy in challenging cases▫ Ostial occlusion ▫ Large side branch at proximal cap▫ Long occlusion (>30mm) ▫ Severe tortuosity or calcification▫ Without stump ▫ Visible continuous collaterals

Collateral selection

Preference - Bypass graft > septal > epicardial

Selective injection of collateral

Surfing technique for crossing invisible septal collateralWiring collateral – achieved with OTW system or dedicated septal dialator(corsair)

Entering septal collaterals large bend or 2 small bend in a work horse wireContrast injection to assess best connection

Hydrophillic polymer jacket wire with <1mm 30-45º tip used to cross recipient artey

Fielder FC,Pilot-50,Whisper, Choicept,Runthrough

Wire should move freely - difficulty to advance – perforation?

whipping of wire - RV or LV entry (rarely pericardium)

Of no consequence if recognized before advancing OTW system

Collateral dilatation using 1.5 mm balloon @ 1-2 atm or Corsair

Epicardial collaterals size most important factor in wiring success should never be dialated

Antegrade crossing

•Simplest form of retrograde technique

•Retrograde wire advanced to distal cap

•Acts as a marker of distal true lumen

•Serves as a target for antegrade wire

Kissing wire

Manipulation of both antegrade and retrograde wires in CTO until they meet

Antegrade wire follow channel made by retrograde wire in true lumen of distal vessel

Retrograde true lumen puncture

Most pure form of retrograde technique(only in 40% retro tech)

Hydrophillic wire advanced to the lesion

Advancment of microcatheter or OTW baloon – additional support

CTO crossed retrogradely using hydrophillic wire or stiffer wire

Manuevers to enhace chance of crossing

Inflating retrograde baloon - coaxial anchor

Stiffer tapered tip or hydrophillic wires

IVUS facilitation of retrograde wire to proximal true lumen

•Basic concept –create subintimal dissection with limited extension only at the site of a CTO.

•Antegrade wire advanced into CTO then to subintimal space.

•Retrograde wire through collateral with microcatheter to distal end of CTO - into the CTO- then to subintimal space.

•Baloon inflation inside CTO using small balloon over the retrograde wire to subintima

•Balloon inflated inside CTO•To keep inflated space open deflated baloon

left in subintimal space

C A R T Controlled antegrade & retrograde subintimal tracking

Two subintimal dissection provide reentry space for antegrade wiring

Antegrade wire advanced along deflated retrograde balloon into the distal true lumen

Limited subintimal tracking (dissection) only in CTO segment

Avoids difficulty of reentering distal true lumen

Dilatation and stent implantation after successful recanalization

Use closest sized baloon inside CTO to create sufficient wire reentry space

Access to distal CTO mainly via septal collatrels, by polymer jacket wire over microcatheter or otw baloon

Septal channel dilatation at 1.25mm baloon at low pressureMajor limitationsLimited access of collatrel channels to target CTO

Empiric estimation of retrograde baloon size

Overall unpredictable procedure time

Reverse CART technique• Engage a guidewire retrogradely in the distal cap of the CTO

• Another wire anterogradely in the proximal cap of the CTO • Retrograde wire advanced in subintimal space into CTO lesion

• Subintimal channel is enlarged by anterograde balloon

• Plaque dissection and modification of the lesion

• Retrograde wire advanced to cross the dissection

• Link up with the anterograde wire in proximal true lumen

• Wire externalized (Exchange length)

• Anterograde PCI done

KNUCKLE WIRE TECHNIQUE

Best suited for long segment of occlusion

Retrograde wire usually a polymer jacket wire manipulated to form a loop at wire tip advanced in subintimal space across CTO Eg: Fielder XT or Pilot-200

Rounded wire loop advanced in subintimal space across CTO without causing perforation

OTW system advanced to this area followed by attempt to reenter true lumen using a stiffwire with short bend or hydrophillic wire Eg: Confianza Pro 12 or Pilot 200

Antegrade vs retrograde

Treating lesion after crossing

CTO crossed by antegrade wiring (kissing wire, just marker,CART

Antegrade CTO PCI can be done

Retrograde balloon can trap antegrade wire to facilitate procedureRetrograde wire crosses to true lumen

Options : Antegrade wiring Retrograde wire externalization Retrograde stent delivery

DES is preferred in CTO PCI

APPROACH

IVUS Navigated WiringIVUS – Depict cross sectional view of coronary tree

IVUS focus on plaque distribution, calcification, reference vessel size & side branch anatomy

Applicability of IVUS in CTO PCI

1)Side branch method to navigate CTO wire into true lumen from proximal cap 2)Subintimal rentry from the proximal true lumen

IVUS guided subintimal rentry – Last resort for getting a subintimal wire into distal true lumen

Applicable even after losing site of distal vascular bed on angio

•1.5-2mm baloon dilatation in presumed subintimal space

•IVUS is advanced into the space monitored to orient 2nd wire to true lumen

Key points a) Ability to translate cross sectional image into 3D

needed

b) 2nd stiff tapered wire over micro catheter - 8f guide mandatory

c) Reentry point should be closer to proximal cap

d) Contrast injection should be withheld esp after small ballon dilatation

Farword looking IVUS

Farword looking IVUS

Farword looking IVUS

Optical coherence reflectometry

n

Debulking of calcific lesion

•Rotational atherectomy•Directional atherectomy•Silverman plaque excision system

Collagenase plaque digestion

Magnetic navigation

•Magnetic navigation wire•Stereo taxis Magnetic Radio Frequency

Guide wire•Magnetic navigation micro robot

Complications

CTO=CIN

Into pocket diary

CTO-PCI IS SAFE

This Diwali -2014

NO CRACKER