Angioplasty guide wires: Why they differ and which to use for what.

Transcription

1 Angioplasty guide wires: Why they differ and which to use for what. Dr Philip MacCarthy BSc MBChB PhD FRCP Consultant Cardiologist King s College Hospital, London, UK. ACI 2012, 27 th Jan 2012

2 Conflicts of interest None

3 What do guide wires do? Facilitate delivery of interventional devices Track through the vessel Access and cross lesions Support interventional devices for various procedures

4 Clinical goal when selecting a guide wire To cross the coronary anatomy safely, independently and without damaging the vessel Select the guide wire according to the clinical setting Decide which properties of your guidewire will facilitate safe delivery of devices to the lesion stents, IVUS catheters etc. Guide Wire Design Clinical Situation

5 Guidewire Performance Characteristics Primary Torque Transmission (steering) Tip Stiffness Lubricity Support Visibility / Markers Secondary Penetration vs. Safety Shaping and Shape Retention Durability Prolapse / Tracking Tactile Feedback

6 Guidewire Performance Trade-Offs Device support Distal Trackability Lesion crossing Non-Traumatising Tip trackability Tip prolapsability Tip formability Tip shape retention

7 Anatomy of a Guide Wire

8 Guidewire Construction The Basics Distal Tip Length: 40 cm Shaft Length: 145 cm Material: Stainless steel / Nitinol Coating : silicone/ Hydrophilic Extension Extension Wire 150cm Core Wire: Stainless steel or Nitinol Outer Material: Spring coil / Polymer Sleeve/Polyurethane Lubricious Coating: Silicone / Hydrophilic Illustration taken by Terumo

9 The 6 Guide Wire Building Blocks 1. Core material 4. Tip style 2. Core diameter 5. Coils & covers 3. Core taper 6. Coatings A Balancing Act of Trade-offs Between Performance and Clinical Attributes. By changing the different building blocks we change the characteristics!

10 1. Core wire materials Stainless steel Durasteel Original core material technology Good support, push force and torque Less flexible than Nitinol Excellent steering High tensile strength SS (28% stronger) Durability Tip shape retention Nitinol Durable for multiple vessel cases Excellent flexibility & Support (super elastic, in combination with SS)

11 2. Core Diameter Diameter affects flexibility, support and torque Smaller Diameter = More Flexibility Larger Diameter = More Support & Torque

12 3. Core Wire Taper Longer taper Less support Successful tracking Shorter taper Successful Tracking Increase in support Tendency to prolapse if taper is at tip Prolapse

13 4. Core Wire Tip Styles Shaping Ribbon Better shapability Flexibility, softness Ability to prolapse Core-to-tip Better steering Force transmission Tactile feedback Tip stiffness/tip-load

14 5. Coils Affect support, steering, tracking and visibility Impact dimension of wire Affect tactile feedback Outer Coils Tip Coils Only

15 Platinum/Nickel Coils Provide Visibility and Tactile Feedback Platinum/Nickel Tip Coils 5 mm Ø Core Wire

16 6. Covers and Coatings Summary Tactile Feedback (related to coils) Polymer Cover with Hydrophilic Coating Lubricity Hydrophobic Coating Hydrophilic Coating No Coating Delivery & Device Interaction

17 Polymer Covers Examples: HT WHISPER MS, HT PILOT, ASAHI FIELDER Polymer (plastic) Provide lubricity Smooth tracking through tortuosity Polymer Cover

18 Coatings Affect lubricity and tracking Facilitate smooth movement Distal cm Types Hydrophilic Hydrophobic

19 Choose your guide wire according to: Clinical scenario Vessel anatomy Lesion location Tortuosity Calcification Lesion morphology long, bifurcation, CTO Device selection IVUS/Length and type of stent needed

20 Clinical Guide Wire Strategy A guide wire is only as good as it s operator

21 Shaping the wire tip Always wet wire before shaping Shape the wire over the shaft of shaping mandrel or wire introducer avoid shaping hydrophilic wires by bending over tip of wire introducer/inserter

22 How to torque a guidewire tips and tricks More tactile feedback if done by hand Never keep pushing if wire does not advance easily concertina effect Either: o Torque and push Or o Spin Use balloon support judiciously

23 Guide Wire Strategy Clinical scenarios Workhorse Tortuous Extra Support STEMI Chronic Occlusions

24 Workhorse Clinical Challenge Majority of procedures,straight forward and complex cases GW Performance Characteristics Flexibility and steering Soft tip Support for device delivery

25 Tortuosity Clinical Challenge Challenging access cases, often with acute vessel take-offs GW Performance Characteristics Requires exceptional steering and tracking capabilities, without prolapse Tip control Long or transitionless core tapers for improved wire tracking Tracking vs support is the key decision

26 Tortuosity Steer-ability Tracking Tip control Support

27 Extra Support Clinical Challenge Device or anatomy requires additional guide wire support GW Performance Characteristics Higher level of support for straightening vessel and assisting with device delivery Don t forget buddy wire

28 CTOs Clinical Challenge Cross occlusion while minimizing vessel trauma GW Performance Characteristics Tip Control, including in-lesion Variable tip stiffness Tapered tip Torqueability and steerability Tactile feedback OTW balloon for exchanges

29 STEMI Clinical Challenge Re-canalise a thrombotic occlusion GW Performance Characteristics Soft, atraumatic Less tendency to stray sub-intimally Support usually less crucial but thrombectomy devices can be bulky

30 Quiz

31 Case 1

32 Case 2

33 Case 3

34 Conclusions Understand the properties of the commonly used guide wires Tailor the guide wire to the clinical scenario, vessel and lesion Get used to using one wire in each category

35 Acknowledgements Lindsey Ockenden Terumo Jonathan Wood - Abbott