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Coronary guidewires


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Cardiology- Coronary guidewires

Published in: Health & Medicine
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Coronary guidewires

  1. 1. CORONARY GUIDEWIRES Dr. Raji Rajan & Dr. A. George Koshy Government Medical College, Trivandrum
  2. 2. •GRUNTZIG First performed Angioplasty in 1974 •1977 – First coronary angioplasty •Polyvinyl Chloride balloon catheter with short guidewire attached to its tip
  3. 3. •1982 – Simpson reported First experience with over the balloon system •It had an independently movable guidewire within the balloon dilation catheter
  4. 4. • To track through the vessel • To access the lesion • To cross the lesion atraumatically • To provide support for interventional devices
  5. 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. 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. 7. STRUCTURE  CORE-Material Diameter Core taper  TIP  COILS, COVERS & COATINGS
  8. 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. 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. 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. 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
  12. 12. 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
  13. 13. Coils
  14. 14. • 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
  15. 15. 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
  16. 16. 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
  17. 17. 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
  18. 18. 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
  19. 19. 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
  20. 20. 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
  21. 21. Shaping the Wire Tip
  22. 22. Steering of the wire • Small alternating rotations to left and right • Excessive rotations should be avoided to prevent wire tip fracture
  23. 23. 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
  24. 24. 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
  25. 25. 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
  26. 26. – 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
  27. 27. 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
  28. 28. 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
  29. 29. 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
  30. 30. 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
  31. 31. 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
  32. 32. 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
  33. 33. 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
  34. 34. 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
  35. 35. Galeo guide wire
  36. 36. 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
  37. 37. Selection of a Guidewire • Vessel anatomy • Lesion morphology • Devices to be used
  38. 38. Conclusion It is suggested that the operator may use a limited number of wires from the several types available for purchase