Guidewires

Guidewires are interventional procedures wires used to guide access, maneuver, or work through structures (e.g. vessels, urinary or biliary system).

They come in different shapes, lengths, diameters, stiffness, and hydrophilicity, and are classified according to their main use into:

• access wires

• maneuver wires

• rail wires

Diameter

The diameter usually ranges from 0.010–0.038 inches, but the most common ones are 0.014, 0.018, and 0.035-inch¹.

Shape

Guidewires generally come with a torque device and may have a curved or straight tip, depending on the vessel or structure to navigate.

Hydrophilic properties

Both hydrophilic and hydrophobic wires are used for vascular access.

Hydrophilic wires

Characteristics

• less thrombogenic compared to hydrophobic wires³

• coated with plastic sheath and hydrophilic material for maximum lubricity

• should be kept wet in a saline bowel to activate the hydrophilic properties

• hard to manipulate - sticky when dry and slippery when wet

• useful when low resistance is needed ² - smooth gliding through small vessels

• needs a torque device for easy manipulation and pinning

Hydrophobic wires

Characteristics

• coated with Teflon or polytetrafluoroethylene (PTFE) ⁴ _- increase lubricity and decreases the friction

• does not prevent thrombus formation around the wire, which can be stripped and migrate during manipulation

• easy to manipulate and grip - do not get sticky

• offer resistance through narrow areas

• may contain heparin coating to reduce thrombogenicity

• some hydrophobic wires (e.g. Bentson wire), can be soaked in heparinized saline to ease exchanges with tools and catheters, and to prevent thrombus formation around the wire²

Indication

Hydrophobic wires make good access wires because they are easy to grip and to stabilize during the initial exchanges.