components and classification of coronary guide wire dr md toufiqur rahman cardiologist
TRANSCRIPT
Dr. Md.Toufiqur Rahman MBBS, FCPS, MD, FACC, FESC, FRCP, FSCAI,
FCCP,FAPSC, FAPSIC, FAHA
Associate Professor of CardiologyNational Institute of Cardiovascular Diseases
Sher-e-Bangla Nagar, Dhaka-1207
Consultant, Medinova, Malbagh branch.Honorary Consultant, Apollo Hospitals, Dhaka and
Life Care Centre, Dhanmondi
COMPONENTS and CLASSIFICATION of CORONARY GUIDE WIRE
•GRUNTZIG First performed Angioplasty in 1974 •1977 – First coronary angioplasty•Polyvinyl Chloride balloon catheter with short guidewire attached to its tip
History of angioplasty
•1982 – Simpson reported First experience with over the balloon system•It had an independently movable guidewire within the balloon dilation catheter
History of angioplasty
Purpose of guide wire use
• To access the lesion• To cross the lesion atraumatically• To reach far end of the vessel• To rail the devices into coronaries • To provide support for interventional
devices
1. 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
4 KEY characteristics
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
Core
• Inner part of the guide wire• 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 SS – superior torque characteristics, can deliver more push,
provides good shape ability 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
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, Covers & Coating
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.
Non-Coated / Hydrophobic wires
Hydrophilic wires• 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
Shape ability and shaping memory
• Shape ability - 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
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 Scientific
Based 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
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
CLASSIFICATION
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 [email protected]
Thank you all