Wire Technology:
How to Choose
Based on
Anatomy and
Strategy
Craig M. Walker, MD, FACC, FACP
Clinical Professor of Medicine Tulane University School of Medicine New Orleans, LA Clinical Professor of Medicine LSU School of Medicine New Orleans, LA Founder, President, and Medical Director Cardiovascular InsAtute of the South Houma, LA NCVH
New Cardiovascular Horizons
KNOW YOUR OPTIONS
DISCLOSURES
Consultant/Medical/Scientific
Boards
•  Abbott
•  Boston Scientific
•  Cardiva
•  Cook Medical
•  CR Bard
•  Lake Regional Medical
•  Medtronic
•  Spectranetics
PVD Training
•  Abbott
•  Bard
•  Boston Scientific
•  Spectranetics
•  TriReme Medical
Stockholders •  CardioProlific •  Cardiva •  Spectrane5cs •  Vasamed Speaker’s Bureau •  Abbo= •  Bard •  Boehringer-­‐ingelheim •  Bristol-­‐Myers-­‐Squibb/Sanofi •  Cardiva •  Cook Medical •  Cordis •  DSI/Lilly •  Gore •  ACHL/Merck •  Spectrane5cs Guide Wire Usage •  Access lesions •  Cross lesions •  Facilitate delivery of interven5onal devices Why is this important? •  If you can’t: 1.  Access the lesion 2.  Cross the lesion 3.  Get your devices to and across the lesion •  You can’t treat the patient!
Guidewire a.ributes affec3ng selec3on •  Wire length
•  Coatings
•  Wire diameter
•  Sleeves
•  Tip penetrance
•  Tip shapability
•  Torquability
•  Tip retention
•  Shaft support
•  Device compatibility
•  Shaft flexibility
•  Cost
•  Visibility
•  Durability
Guide Wire Key Components Core Diameter Func5onal Diameter Coa5ngs Core Material Coils & Covers Core Taper/Grind Tip Style (0.014”/0.018”/0.035”) The Building Blocks of All Guide Wires The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! 1) Guide Wire Core Materials Core material affects flexibility, support, steering and tracking Stainless Steel (SS) Ni3nol (NiTi) More Torqueable and rigid More Flexible Be=er columnar support Won’t kink Genera3on 1: Stainless Steel Genera3on 1: Ni3nol Genera3on 2: High Tensile Strength SS Genera3on 2: Stainless Steel+NiTi The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! Guidewire Basics: Core Diameter •  Larger Diameter = Increased rail support & torque, may enable vessel straightening (i.e. sheath placement in a 5ght iliac bifurca5on) •  Smaller Diameter = Increased flexibility & trackability through the vessel Strength=Radius4 Strength 0.018”= 2.73 X Strength of 0.014” Selec3on Considera3ons •  Clinical needs such as tortuosity (increased flexibility), crossing 5ght stenosis •  Device compa5bility and support •  .014” most atherectomy + need for column strength The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! 3) Core Tapers and Grinds Core Taper = The part of the wire where the diameter of the core changes over a set distance Core Grind = The part of the core with constant diameter Grind 1 Taper 1 Grind 2 Taper 2 3) Core Tapers and Grinds Broad, gradual, or long tapers §  Offers acute vessel access, improved tracking §  The wire follows itself well around bends Grind Longer Tapers Abrupt or short tapers §  Creates support in shorter distance §  Greater tendency to prolapse Shorter Taper Grind Guide Wire Support Charts – How to Read Them 400 350 300 250 200 150 100 50 0 0 S5ffness (grams force) 450
Taper Taper 5 10 15 20 25 Distance From Guide Wire Tip (cm) 30 35 40 The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! 4) Guide Wire Tip Design Affects Steering and Durability Design Op3ons ü  Force transmission ü  Be=er steerability ü  Tac5le feedback ü  Easy 5p shapeability ü  Flexibility, soiness ü  Ability to prolapse ü  Ideal for peripheral vessels ü  More durable ü  Ability to prolapse ü  More delicate Core-­‐to-­‐5p Shaping Ribbon Guide Wire Penetra3on Power Understanding Tip Diameter and S3ffness Tip S3ffness = 4.0g Tip Diameter 0.012” Area of Guide Wire Tip r Penetra3on Power: (Pressure) Tip S5ffness / Area of Guide Wire Tip: .004kg/
(3.14*.006”2) Penetra5on Power = 40 Kg/in2 Guide Wire Tip The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! 5) Guide Wire Tip Coils •  Affect support, steering, tracking and visibility (radiopacity) •  Impact dimension of wire •  Affect tac5le feedback Tip Coils Outer Coils Tip Coils Only 5) Guide Wire Covers •  Polymer or plas5c •  Provide •  Smooth tracking through tortuosity •  Not to be confused with Hydrophilic coa5ng Polymer Cover Polymer Tip 5) Guide Wire Tip Coils and Covers -­‐ Combina3ons •  Tip coils plus: •  Intermediate coils •  Bare core •  Plas5c cover •  Polymer Polymer Cover + Tip Coils •  Polymer over 5p coils Exposed Coils for Be=er Tac5le Response The 6 Guide Wire Core Components 1 Core Material 2 Core Diameter 3 Core Taper 4 Tip Design 5 Coils and Covers 6 Coa5ngs A Balancing Act of Trade-­‐offs Between Performance and Clinical A=ributes; by Changing the Different “Building Blocks”, We Change the Characteris5cs! 6) Guide Wire Coatings: Hydrophobic Coating
•  Repeal water to create a smooth, “wax-­‐like” surface •  No actua5on with water required •  Reduces fric5on & provides improved device trackability 6) Guide Wire Coatings: Hydrophyllic Coating
•  Minimizes fric5on & provides be=er device trackability •  A=racts water to create a slippery “gel-­‐like” surface 6) Guide Wire Coa3ngs: Lubricity vs. Tac3le Feedback “THE TRADE-­‐OFF” Guide wire Ap with: Lubricity Polymer Cover With Hydrophilic Coa5ng Hydrophilic Coa5ng Hydrophobic Coa5ng No Coa5ng Tac5le Feedback Coils: Impact on Visibility •  Platinum, Palladium, Tungsten, and Stainless Steel
•  Type of material and Durometer (density) of material impacts visibility
•  Platinum most radiopaque, Stainless steel least
•  Length of radiopaque coils
Clinical benefit of visibility:
Guidewire Tip Shaping Techniques •  Penetrating the lesion entry point
Straight or small angle at the very distal
tip
•  Secondary bend for navigating tortuosity
Small angle at the very distal tip, subtle
secondary bend
•  Re-entering true lumen from subintima
More acute angle like a J-tip
How Guidewires Fail to Cross Wire tip prolapses at the cap à wire with higher tip gram load , sharp short angle, SC
Proximal segment of tip buckles à wire with higher tip gram load; hydrophilic coating or
advance a support catheter near tip
Tip enters lesion, wire fails to follow à wire with higher rail support; lower profile; hydrophilic,
or advance a support catheter
Wire Crosses but device fails to cross à wire with higher rail support or lower profile system
Keys To Success: Selec3ng a guidewire for crossing •  Wire escala5on approach •  Frequent wire exchanges •  Wire selec5on for penetra5ng the cap, versus naviga5ng the middle of the lesion, versus device delivery •  Shaping of the 5p •  Use of a support catheter •  ACCESS •  Push, torque, reach, support •  Visualiza5on (hiberna5ng vessel and gepng closer to site to be imaged), minimiza5on of contrast use •  Approaching the soier cap or avoiding collateral vessels. Conclusion •  Trea5ng complex lesions can be challenging. •  Wires can fail in many ways (failure to cross, to deliver a device, or cause distal injury). •  Familiarity with a mul5tude of wires can benefit in these cases. •  Understanding wire technical a=ributes and impact on clinical performance will help select the right wire for the right case. •  Non-­‐wire factors affect wire success. Closing Remarks / Thank You