Introducers, dilators and guidewires facilitate catheter placement and exchange by navigating vessels to reach a lesion or vessel segment. These devices require rigorous testing and validation to ensure that they perform according to their intended use and labeling.
ISO 11070 outlines general requirements for testing sterile single-use intravascular introducers, dilators and guidewires. ºÃÉ«TV offers comprehensive testing services according to FDA guidance document recommendations and ISO standards.
Many guidewires assist in the placement of balloon catheters during percutaneous transluminal coronary angioplasty (PTCA) and percutaneous transluminal angioplasty (PTA). Introducer catheters are another device type used in conjunction with a catheter to facilitate introduction into the vascular system.
The devices are evaluated for:
- Pushability: amount of force needed to advance the guide wire
- Steerability: ability and responsiveness of the guidewire tip to navigate vessels
- Torque: response of the guidewire to turning by the operator when navigating vessels
- Opacity: level of visibility under fluoroscopic imaging
Introducers & guidewire test methods
Simulated use testing evaluates how guidewires will perform in their intended scenario. We use the device in combination with other ancillary devices (e.g., introducer, guiding catheter), if applicable, according to the instructions for use. The anatomical model is designed per the manufacturer’s specifications to mimic the indicated target vasculature with input on lumen diameter, bend radii, bend reversals, number of bends, tracking length, and coefficient of friction of tracking materials. Observations regarding compatibility with secondary devices, appropriate preparation, the maneuverability of the device through the simulated use model, and the integrity of the device before, during, and after use are reported.
Performing tensile testing of each joint to failure demonstrates that the device is capable of withstanding tensile forces greater than those expected in clinical use. Samples are prepared per the instructions for use and then pre-conditioned as needed to simulate worst-case conditions and tracked through a simulated use model.
Tip pull testing measures the tensile force needed to separate the distal tip from the guidewire. This method is useful for guidewires that contain one or more joints at the distal tip (e.g., spring or coil tips). Samples are prepared per the instructions for use and then pre-conditioned as needed to simulate worst-case conditions and tracked through a simulated use model.
The simulated use model allows for torque strength testing of guidewires, where the movement of the distal end of the device is constrained, and the proximal end of the guidewire is rotated until failure. The number of rotations to failure and the failure mode for each device tested are reported. Similar to torque strength testing, torqueability is evaluated using the simulated use model. Torqueability testing leaves the distal end unconstrained, and rotates the proximal end of the guidewire. The report includes the rotational input to the resulting distal rotation at 90-degree intervals and the proximal-to-distal rotational ratio for each sample.
Since guidewires may be subject to bending forces during use, we evaluate resistance to kinking (and other failure modes) when samples bend around anatomically-relevant radii. Samples are prepared per the instructions for use and then pre-conditioned as needed to simulate worst-case conditions. To evaluate the resistance to kinking, we track each sample through a simulated use model where each sample is bent around mandrels of decreasing radii until failure (e.g., kink, deformation, fracture) or to the smallest bend radii expected during clinical use. The report includes the mandrel sizes tested, which mandrel caused device failure, the location of failure and the type of failure observed.
Tip flexibility testing of the mechanical properties of guidewire tips allows for safe and successful navigation through tortuous vessels. After samples are prepared per the instructions for use and then pre-conditioned as needed to simulate worst-case conditions, we identify the force that induces buckling deformation when the device is held at 5, 10 and 20 mm from the distal tip.
We visually inspect guidewires for defects, including kinks, cracks, deformations or debris, at different magnifications.
Additional testing services for guidewires, dilators and introducers include coating integrity, particulate evaluation and corrosion.
For more information about our cardiovascular device testing services, or to request a quote, contact us today.
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