Access & devices
Guidewire
A flexible wire advanced through a needle or catheter to establish and maintain a safe path along which other devices are exchanged.
- Owner
- WIRS education committee
Overview
A guidewire does not treat anything itself — its role is to establish and hold a safe path so that other devices (dilators, sheaths, catheters) can be exchanged over it without losing access. Wires vary along several axes: overall stiffness (a floppier wire is more forgiving in tortuous or fragile anatomy; a stiffer wire gives the support needed to advance a sheath or catheter over it); tip shape (straight or angled/curved — sometimes called a J-tip — to help the wire follow the vessel rather than the wall); and surface coating (a hydrophilic-coated wire is slicker and often used to negotiate tighter or more tortuous paths, at the cost of being harder to feel as it advances).
Sizing and compatibility
- Guidewires are conventionally described by diameter in thousandths of an inch (for example, 0.035 in or 0.018 in) and by length, not by the French scale.
- A wire's diameter must be compatible with the inner lumen of whatever needle, catheter or sheath it passes through — matching this compatibility, not the wire's diameter alone, is what the supervising operator judges for each case.