Guidewire tip: Difference between revisions
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There can be one or more joints made of different materials in the tips of guidewires. The number of joints and the nature of the joints influence the clinical performance of the wires. These joints can serve as hinge points and bend during guide wire passage. | |||
There | |||
The number of joints and the nature of | |||
[[Image:Joint_wire_bends.jpg]] | [[Image:Joint_wire_bends.jpg]] |
Revision as of 21:04, 23 October 2011
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Characterizing the Physical Characteristics of a Coronary Guidewire Using the Tip Load
One way of quantifying some of the physical features of a coronary guidewire is by using a strain gauge to measure the force needed to bend a wire when exerted on a straight guidewire tip, at a point 1 cm from the tip. Using this method, the tip loads in ascending order are (from less stiff to more stiff) 3 gm, 4.5 gm, 6 gm, 9 gm and 12 gm (ultra stiff). As stiffness increases the wire becomes prone to perforating the vessel.
Core To Tip Guidewires
When the core is extended to the tip, that increases pushability, precise steering, tip control and torquability. This can be a useful feature for eg. in probing chronic total occlusions.
With unibody wires there is more torquability, pushability and tactile feel. With two piece tip wires shaping is easy and the wire is likely to retain the shape “wire memory”
Shaping Ribbon
Incorporation of a shaping tip yields a softer tip that allows for shape retention.
Spring Coil Tip
1. Spring coil - Safer than hydrophilic coated or polymer tip wires - less risk of perforation
2. Distal weld
Spring Coils
- Outer coils only
- Tip coil only
Tip Cover
- Polymer or plastic
- Provide lubricity
- Smooth tracking through tortuosity
Polymer Tip (Cover)
Polymer instead of the spring coil with hydrophilic coating
Improved trackability with the compromise of reduced tactile feedback / feel
Eg: PT Graphix™ Intermediate Guide Wire, ChoICE PT wire
”Combination” Tips
- Tip coils plus
- Intermediate coils
- Bare core
- Plastic cover
- Polymer
- Polymer over tip coils
Determinants of Tip Flexibility
There can be one or more joints made of different materials in the tips of guidewires. The number of joints and the nature of the joints influence the clinical performance of the wires. These joints can serve as hinge points and bend during guide wire passage.