Wire Technology: How to Choose Based on Anatomy and Strategy

Transcription

1 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 Institute of the South Houma, LA

2 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 Spectranetics Vasamed Speaker s Bureau Abbott Bard Boehringer-ingelheim Bristol-Myers-Squibb/Sanofi Cardiva Cook Medical Cordis DSI/Lilly Gore ACHL/Merck Spectranetics

3 Guide Wire Usage Access lesions Cross lesions Facilitate delivery of interventional 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!

4 Guidewire Attributes Affecting Selection Wire length Wire diameter Tip penetrance Torquability Shaft support Shaft flexibility Visibility Coatings Sleeves Tip shapability Tip retention Device compatibility Cost Durability

5 Guide Wire Key Components Diameter Material Taper/Grind Functional Diameter (0.014 /0.018 /0.035 ) Coatings Coils & Covers Tip Style The Building Blocks of All Guide Wires

6 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

7 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

8 1) Guide Wire Materials material affects flexibility, support, steering and tracking Nitinol (NiTi) Stainless Steel (SS) More Torqueable and rigid More Flexible Better columnar support Won t kink Generation 1: Stainless Steel Generation 1: Nitinol Generation 2: High Tensile Strength SS Generation 2: Stainless Steel+NiTi Polymer core/wire wrap More Torque Sion Sion Blue Command

9 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

10 Guidewire Basics: Diameter Larger Diameter = Increased rail support & torque, may enable vessel straightening (i.e. sheath placement in a tight iliac bifurcation) Smaller Diameter = Increased flexibility & trackability through the vessel Strength=Radius 4 Strength = 2.73 X Strength of Selection Considerations Clinical needs such as tortuosity (increased flexibility), crossing tight stenosis Device compatibility and support.014 most atherectomy + need for column strength

11 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

12 3) Tapers and Grinds Taper = The part of the wire where the diameter of the core changes over a set distance Grind = The part of the core with constant diameter Grind 1 Grind 2 Taper 1 Taper 2

13 3) 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

14 Guide Wire Support Charts How to Read Them Stiffness (grams force) Taper Taper Distance From Guide Wire Tip (cm)

15 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

16 4) Guide Wire Tip Design Affects Steering and Durability Design Options ü Force transmission ü Better steerability ü Tactile feedback ü Ideal for peripheral vessels ü More durable -to-tip ü Easy tip shapeability ü Flexibility, softness ü Ability to prolapse ü Ability to prolapse ü More delicate Shaping Ribbon

17 Guide Wire Penetration Power Understanding Tip Diameter and Stiffness Tip Stiffness = 4.0g Tip Diameter Area of Guide Wire Tip r Penetration Power: (Pressure) Tip Stiffness / Area of Guide Wire Tip:.004kg/(3.14*.006 2) Penetration Power = 40 Kg/in2 Guide Wire Tip

18 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

19 5) Guide Wire Tip Coils Affect support, steering, tracking and visibility (radiopacity) Impact dimension of wire Affect tactile feedback Tip Coils Outer Coils Tip Coils Only

20 5) Guide Wire Covers Polymer or plastic Provide Smooth tracking through tortuosity Not to be confused with Hydrophilic coating Polymer Cover Polymer Tip

21 5) Guide Wire Tip Coils and Covers Combinations Tip coils plus: Intermediate coils Bare core Plastic cover Polymer Polymer Cover + Tip Coils Polymer over tip coils Exposed Coils for Better Tactile Response

22 The 6 Guide Wire Components 4 1 Tip Design Material 2 Diameter 3 Taper 5 Coils and Covers 6 Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes; by Changing the Different Building Blocks, We Change the Characteristics!

23 6) Guide Wire Coatings: Hydrophobic Coating Repeal water to create a smooth, wax-like surface No actuation with water required Reduces friction & provides improved device trackability

24 6) Guide Wire Coatings: Hydrophyllic Coating Minimizes friction & provides better device trackability Attracts water to create a slippery gel-like surface

25 6) Guide Wire Coatings: Lubricity vs. Tactile Feedback THE TRADE-OFF Polymer Cover With Hydrophilic Coating Guide wire tip with: Lubricity Hydrophilic Coating Hydrophobic Coating No Coating Tactile Feedback

26 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:

27 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

28 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

29 Keys To Success: Selecting a guidewire for crossing Wire escalation approach Frequent wire exchanges Wire selection for penetrating the cap, versus navigating the middle of the lesion, versus device delivery Shaping of the tip Use of a support catheter ACCESS Push, torque, reach, support Visualization (hibernating vessel and getting closer to site to be imaged), minimization of contrast use Approaching the softer cap or avoiding collateral vessels.

30 Conclusion Treating 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 multitude of wires can benefit in these cases. Understanding wire technical attributes and impact on clinical performance will help select the right wire for the right case. Non-wire factors affect wire success.

31 Thank You