Cardiology- Coronary guidewires

1. CORONARY GUIDEWIRES
Dr. Raji Rajan
&
Dr. A. George Koshy
Government Medical College,
Trivandrum

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

3. •1982 – Simpson reported
First experience with over
the balloon system
•It had an independently
movable guidewire within
the balloon dilation
catheter

4. • To track through the vessel
• To access the lesion
• To cross the lesion atraumatically
• To provide support for interventional devices

5. Guidewire main characteristics
 Torque control Is an ability to apply rotational force at a
proximalend of a guidewire and have that force transmitted
efficiently to achieve proper control at the distal end
 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
 Steerability Is an ability of a guidewire tip to be delivered to
the desired position in a vessel
 Flexibility Is an ability to bend with direct pressure

6.  Prolapse tendency Tendency of the body of a wire
not to follow the tip around bends
 Radiopacity/visibility Is an ability to visualise a
guidewire or guidewire tip under fluoroscopy.
 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
 Crossing Is an ability of a guidewire to cross lesion
with little or no resistance
 Support Is an ability of a guidewire to support a
passage of another device or system over it

7. STRUCTURE
 CORE-Material
Diameter
Core taper
 TIP
 COILS, COVERS & COATINGS

8. Core
• Inner part of the guidewire
• Extents 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

9. 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

10. 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 widely spaces
gradual tapers increases support and transmission
of push force
• Longer tapers and larger numbers of segmented
tapering increases flexibility

11. 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 weld
• 2-piece→ easy shaping & durable shape
memory
• 1-piece →better force transmission to tip &
greater “tactile response” for operator

13. 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

14. Coils

15. • 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

16. Hydrophobic
• Applied over the entire working length except
the distal tip
• Require no activation by liquid
• ↓friction, ↑trackability
• Preserves tactile feel, allows easier
anchorability / parking - esp CTO
• Silicone, Teflon

17. 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 perforation
Tendency to stick to angioplasty cath
• Useful in negotiating tortuous lesions and in
“finding microchannels” in total occlusions

18. 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

19. Classification
Based on Tip Flexibility
• Floppy – Eg:- Hi torque balance middle weight, Hi
torque balance, Hi torque transvers
• Intermediate – Eg:- Hi torque intermediate,
Choice intermediate
• Standard – Shinobi, Boston Scientific
Based on Device support
• Light – Eg:- Hi torque balance
• Moderate – Eg:- Hi torque balance middle Weight
• Extra support – Eg:- Hi torque whisper

20. Based on coating
• Hydrophilic : Eg:- CholCETM PT Floppy
• Hydrophobic : Eg:- Asahi soft
Depending 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

22. 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

23. Shaping the Wire Tip

24. Steering of the wire
• Small alternating rotations to left and right
• Excessive rotations should be avoided to
prevent wire tip fracture

25. 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

26. 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

27. 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

28. – 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

29. 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

30. 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 lesion
Complications
• In some cases cause hemodynamic compromise
and ischemia

32. 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

33. 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

34. 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

35. 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

36. 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

38. 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

40. Galeo guide wire

41. Guidewire Strategies for Approaching CTO
• A) Guidewires for
Approaching Micro-channels
– Crosswire NT
– Whisper / Pilot
– Rinato
– Shinobe / Shinobe Plus
– ChoICE PT / ChoICE PT ES
– PT Graphix
– PT2
• B) Guidewires for Drilling
Strategy
– Persuader
– Miracle Bros
– Cross-It
• C) Guidewires for Penetrating
Strategy
– Cross IT
– Conquest Pro
– Liber 8
• D) Guidewires for Retrograde
Technique
– Fielder/FielderFC
– X -treme
– Whisper
– ChoICE PT2
– Runthrough / Runthrough
Hypercoat

42. Selection of a Guidewire
• Vessel anatomy
• Lesion morphology
• Devices to be used

43. Conclusion
It is suggested that the operator may use a
limited number of wires from the several
types available for purchase