CORONARY GUIDEWIRES

CHOICE & APPROPRIATE USE IN PCI

Dr Vallabhaneni Sri Ram BhupalNIMS,Hyderabad,India

CONTENTS

• COMPONENTS OF A GUIDE WIRE• CLASSIFICATION• WIRES FOR DIFFERENT OCCASIONS• GUIDEWIRE MANIPULATION• COMPLICATIONS

•GRUNTZIG First performed Angioplasty in 1974 •1977 – First coronary angioplasty•Polyvinyl Chloride balloon catheter with short guidewire attached to its tip

•1982 – Simpson reported First experience with over the balloon system•It had an independently movable guidewire within the balloon dilation catheter

Purpose

• To reach far end of the vessel• To rail the devices into coronaries • To access the lesion• To cross the lesion atraumatically• To provide support for interventional devices

4 KEY characteristics1. Torque control

Is an ability to apply rotational force at a proximal end of a guidewire and have that force transmitted efficiently to achieve proper control at the distal end

2. Trackability Is an ability of a wire to follow the wire tip around curves and bends without bucking or kinking, to navigate anatomy of vasculature

3. Steerability Is an ability of a guidewire tip to be delivered to the desired position in a vessel

4. Flexibility Is an ability to bend with direct pressure

Other features 5. Prolapse tendency

Tendency of the body of a wire not to follow the tip around bends

6. Radiopacity/visibility Is an ability to visualise a guidewire or guidewire tip under fluoroscopy.

7. Tactile feedback Is tactile sensation on a proximal end of a guide wire that physician has that tells him what the distal end of the guidewire is doing

8. Crossing Is an ability of a guidewire to cross lesion with little or no resistance

9. Support Is an ability of a guidewire to support a passage of another device or system over it

STRUCTURE

CORE-Material Diameter Core taper TIP COILS, COVERS & COATINGS

Core

• Inner part of the guidewire• Extends through the shaft of the wire from the

proximal to the distal part• Distal taper• Stiffest part of the wire that gives stability and

steerability

Core Material Core material affects the flexibility, support, steering

and trackability • Stainless steel

– superior torque characteristics, can deliver more push, provides good shapeability and excellent support

– more susceptible to kinking and is less flexible• Nitinol

– pliable but supportive, less torquability than SS– generally considered kink resistant & have a tendency

to return to their original shape, making them potentially less susceptible to deformation during prolonged use

Core Diameter• Influences the performance of the wire• Larger diameter improves support and allows 1:1

torque response• Smaller diameter enhances the flexibility

Core taper• Variable length• Continuous/segmented• Short taper and smaller number of wide spaces

gradual tapers increases support and transmission of push force

• Longer tapers and larger numbers of segmented tapering increases flexibility

Tip

• Tapers distally to a variable extent – 2-piece core- distal part of core does not reach

distal tip of wire→ shaping ribbon, extends to distal tip

– 1-piece core- tapered core reaches distal tip.• 2-piece→ easy shaping & durable shape

memory• 1-piece →better force transmission to tip &

greater “tactile response” for operator

Coils, Covers & Coating

Keeps the diameter at .014 inch• Coils

– Stainless steel– Outer coil Design – Coils placed over tapered core and tip

of the wire– Tip coil Design – Tip alone is covered with coils– Flexibility, support, steering, tracking, visibility & tactile

feedback– Radio opaque platinum coils– Intermediate coils placed on the working length of the wire

Coils

Radio-opaque tip

• Visibility of the wire tip is provided by radiopaque platinum coils that are usually placed at the distal tip 2 to 3 cm in length, but maybe much longer.

• Galeo Wires – 3 cm distal radio-opaque tip.• BMW wire – 3 cm distal radio-opaque tip

• Covers– Polymer or plastic– Lubricity

• Coating– Distal half– Affects lubricity and tracking– Creates tactile feel– Reduces friction – Facilitates movement of wire within the vessel and

deliverability of intervention equipment

Non-Coated / Hydrophobic wires

Pros• More controllable (and therefore less likely to dissect)• Provide better tactile feel

Cons• Poor trackability• Wire tip becomes stiffer, torque response increases,

but less tip resistance is transmitted to the operator, making it easier to enter a false channel.

• Hydrophobic coatings are silicone based coatings which repel water and are applied on the working length of the wire, with the exception of the distal tip. They require no activation by liquids to create a "wax-like" surface and to achieve the desired effect— to reduce friction and increase trackability of the wire. Silicone coating has higher friction, more stable feel inside the vessel.

Hydrophilic• Applied over the entire working length of wire

including tip coils• Attracts water - needs lubrication• Thin, non slippery, solid when dry→ becomes a gel

when wet– ↓friction– ↑trackability– ↓Thrombogenic↓tactile feel- ↑risk of perforationTendency to stick to angioplasty cath

• Useful in negotiating tortuous lesions and in “finding microchannels” in total occlusions

Shapeability and shaping memory

• Shapeability - allows to modify its distal tip conformation

• Shaping memory - ability of tip to return back to its basal conformation after having been exposed to deformation & stress– Both do not necessarily go in parallel– SS core wires -easier to shape (↑memory- nitinol

core)– 2-piece core + shaping ribbon - easier to shape &

↑memory

HOW TO CLASSIFY CORONARY GUIDE WIRES?

CLASSIFICATION

• NO UNIFORM CLASSIFICATION • BUT SOME CATEGORISATION

Table 14 Categorisation/classes of guidewires

Classification

Based on Tip Flexibility• Floppy – Eg:- Hi torque balance middle weight, Hi

torque balance,Choice floppy• Intermediate – Eg:- Hi torque intermediate,

Choice intermediate• Standard – Shinobi, Boston ScientificBased on Device support• Light – Eg:- Hi torque balance• Moderate – Eg:- Hi torque balance middle Weight• Extra support – Eg:- Hi torque whisper,Choice

“Support”

• Indicator of the core strength

• More stronger the core – more support

Floppy

ES – Extra-Support

Grand-Slam

Iron-man

Based on coating• Hydrophilic : Eg:- CholCETM PT Floppy• Hydrophobic : Eg:- Asahi softDepending on tip load• Floppy, Balanced & Extra support

• Tip load - force needed to bend a wire when exerted on a straight guide wire tip, at 1 cm from the tip– Floppy - <0.5g– Balanced – 0.5-0.9g– Extra support - >0.9g

BASED ON CLINICAL SCENARIO

Commonly Used Workhorse Guidewires

• ATW/ATW Marker• Stabilizer• BMW / BMW Universal• Zinger• Cougar XT• Asahi Light / Medium• Asahi Standard• Asahi Prowater Flex• Choice Floppy• Luge• IQ• Forte Floppy• Runthrough NS• Galeo

Balance Middleweight Universal wire (Abbott Vascular/Guidant, Santa Clara, CA)

• Quite steerable - tip is suitable for bending in a “J” configuration for distal advancement into the distal vessel bed with minimal trauma while still maintaining some torque

• shape retention relatively poor -any J configuration tends to become magnified over time → consequent loss in steerability

• moderately torquable- progression - minimal friction (light hydrophilic coating) - Dye injection may also be helpful to propagate distal advancement

• suitable for rapid, uncomplicated interventions• low risk to cause dissections/distal perforations• support - low to moderate

CHOICE FLOPPY

SELECTION OF GUIDEWIRES FOR SPECIAL LESIONS

The selection of a guidewire

• Essential component

• INFLUENCED BY• vessel anatomy• the lesion morphology• the devices to be used• operator's experience and preference.

LEFT MAIN PCI

• The choice of a guidewire is not of critical importance.

• Wire selection usually includes spring tip guidewire designed for frontline lesions, for example, ChoICE™ Floppy (Boston Scientific), Hi-Torque Balance Middleweight (Abbott Vascular)

• FOR LEFT MAIN OR RCA OSTIAL PCI AN EXTRASUPPORT WIRE IS PREFERED

BIFURCATION PCI

• In the presence of difficulties accessing the side branch some hydrophilic wires such as the ChoICE™ PT Floppy (Boston Scientific), PT Graphix™ (Boston Scientific) or Asahi Fielder (Abbott Vascular) may become useful.

• These wires have higher risk to perforate the distal vessel if allowed to migrate into small side branches or too distally. Therefore it is important to monitor the distal position of the wire tip. These wires also should not to be jailed because of the risk of wire rupture during pullback.

MAIN VESSEL TRACKING

Short tapering better

DISSECTIONS

• ChOICE Floppy • Asahi Soft .• The parallel wire technique can be recommended

if a dissection plane is entered with the first wire

• Ochiai M, Ashida K, Araki H, Ogata N, Okabayashi H, Obara C. The latest wire technique for chronic total occlusion. Ital Heart J 2005;6:489-93..

CALCIFIED LESIONS

• ChoICE Floppy (Boston Scientific).• If it fails to cross the lesion, the next step is to

choose floppy hydrophilic wire such as the ChoICE PT Floppy (Boston Scientific) or Asahi Fielder (Abbott Vascular)

TORTUOUS ANATOMY

• Very floppy wire with support for device delivery could be used

• BMW • FIELDER FC• WHISPER ES• WIGGLE WIRE

CTO WIRES

CLASSIFICATION OF CTO WIRES

CTO guide wire techniques

Lesion specific CTO approaches

SLIDING

Micro-channels present

CTO’s < 6 months

ISR total occlusions

STAR technique

Hydrophilic wiresFielder,CrosswireNT, HT Pilot, Whisper, Choice PT

Lesion specific CTO approaches

DRILLING (controlled)

“Workhorse technique”

Most CTOs with discrete

entry point after initial attempt

with soft (intermediate wires)

Stiff , hydrophobic non-tapered wires

MiracleBros (3 g, 4.5 g and 6 g), Persuader (3 g and 6 g)

and Cross-IT XT (100/200/300)

Lesion specific CTO approaches

Penetration

• Blunt entry point

• Heavily calcific or resistant lesions

• Alternative to “drilling” as the

“work horse technique” after initial soft wire failure

Super stiff tapered wires

Conquest Pro (9 g, 12 g), Cross-IT XT

400, MiracleBros 12

GUIDEWIRES FOR RETROGRADE TECHNIQUES

– Fielder/FielderFC – X -treme – Whisper – ChoICE PT2– Runthrough / Runthrough Hypercoat

COMMONLY USED CTO WIRES

Fielder™ / Fielder FC™ (Asahi Intec Co.)

• Special guidewire - distal coil coated with polymer sleeve & further coated with a hydrophilic coating

• Provides advanced slip performance & trackability for highly stenosed lesion & tortuous vessels

• Very good torque performance • Combines both slide and torque performance • Primary wire used in the retrograde technique of

recanalization of CTO

Whisper

• Durasteel™ Core-to-tip designed to improve steering, durable shape retention and tactile feedback

• Full Polymer cover with Hydrophilic coating intended for deliverability and smooth lesion access

• Responsease™ “transitionless” core grind designed to provide improved tracking and better torque response

• Tip coils designed to provide softer, shapeable tip and also improve tactile feedback

SUMMARY OF WIRES

WORKHORSE WIRES

EXTRA SUPPORT WIRES

CTO WIRES

Guidewire Manipulations

• Two step process• Shaping the wire tip

– It minimizes the amount of force applied to the wire

– For steering into the vessel– For visualization of torquing effort

Shaping the Wire Tip

Steering of the wire

• Small alternating rotations to left and right• Excessive rotations should be avoided to

prevent wire tip fracture

Optimum guide wire positioning

• Should be placed as distally as possible in the target vessel

• Allows extra support when crossing with balloon/stent catheters

• ↓ chance of the wire becoming displaced backwards across the lesion and necessitating re-crossing

Avoid vessel perforation when positioning wires with hydrophilic coatings very distally

Strategies if Guidewire fails to cross

• Make the guide more coaxial with the lumen of the artery

• Use a balloon to direct the wire• Modify the bend at the tip of the wire• Change the wire

Complications• Vessel perforations

– Uncommon <1%– Risk factors

• Hydrophilic wires, core to tip• Chronic total occlusions

– Diagnosis• Angiographic diagnosis• Small extraluminal extravasation of blush in the distribution

of target vessel• Emergency echo to r/o pericardial effusion and tamponade

– Prognosis• Extend of extravasation into pericardium

– Classification• Type I – Extraluminal crater without extravasation• Type II – Containing pericardial or myocardial

blushing • Type III - having≥ 1 mm diameter with contrast

streaming: and cavity spilling– Management

• Reversal of anticoagulations• Prolonged balloon inflation• PTFE covered stent• Coil embolization• Use of gel foams

Pseudolesions/Concertina effect• Stenosis that appears in any artery after the coronary

guidewire is placed in the artery• Appears in tortuous vessels that have been straightened

out by the guidewire

Diagnosis• Will disappear if the wire is withdrawn• Replacement of a stiff wire with a flexible floppy

wire eliminates pseudolesion• Microcatheter or a balloon catheter can be

placed distal to the lesionComplications• In some cases cause hemodynamic compromise

and ischemia

Guidewire Entrapment

Factors• Presence of calcified vessels (Eg:- RCA)• Repeated use of wire for multiple interventions• Repeated attempts at crossing the same lesion

multiple times with the same wire• Two wires my become entrapped when the

“Buddy wire” technique is used• Crossing fresh stent struts

Management

• Advance a small profile balloon or a small caliber catheter (transit catheter) to the attachment site and pull back gently

• When a second or “buddy wire” gets trapped between a stent and the vessel wall gentle traction can be used

• Surgery

Guidewire fracture and Embolization

• Risk factors are calcified lesion, bifurcation stenting and prolonged procedures

• Management– Surgery– Snaring the Embolized wire fragment

• The Amplatz Gooseneck Microsnare• The EnSnare Triple Loop Device• The X Pro Micro Elite Snare• The Alligator Retrieval Device

– Push and paste

THANK YOU

Husband must obey wife but not reverse

• Operator is husband until his guide wire is not in coronary artery but then you know …..