Catheter Testing and Delivery System Testing

An in-line continuous particulate counting system is used to assess the number and sizes of  particles generated during simulated use in real-time inside an anatomical model.

Catheters are connected to a partially filled syringe, a negative pressure is applied by pulling on the syringe plunger, visual inspection is performed to detect any bubbles forming in the syringe.

ViVitro Labs provides a large array of computational modeling tools, such as Finite Element Analysis (FEA), Computational Fluid Dynamics (CFD), Fluid-Structure Interaction (FSI) that can be used to assess the impact of anatomical and physiological boundary conditions on the design of a medical devices. 

Balloon pressure and corresponding balloon diameter is verified for the full range of recommended inflation diameters.

Balloons must withstand multiple inflations during clinical use to avoid inducing device failure or vessel damage.

The time to inflate and deflate a balloon catheter to a predefined target pressure is measured.

Determination of maximum pressure a balloon can withstand clinically before bursting also known as the rated burst pressure (RBP).

The pressure at which the entire catheter assembly bursts.

Accessories are used with the catheter. For examples guidewires, guiding catheters, and introducer sheaths are used with the catheter to show compatibility of lumens.

A Scanning Electron Microscope (SEM) and/or an optical microscope with proper magnification is used to inspect the surface defects and coating integrity of the device before and after testing. Coating anomalies, defects or artefacts are located and documented.

The catheter is immersed in a physiological saline solution for 5 hours then in boiling distilled or dionized water for 30 min. Samples are kept at 37°C for 48 hours before cooling down to room temperature. Test samples are visually inspected for traces of corrosion with an optical microscope in comparison to reference samples.

Uses the proximal load cell to measure the ability of the device to advance and withdraw, with no loss of function or damage to the tortuous anatomy, over a specific lesion site. The roller system and the camera allow determining the worst-case lesion that the stent can withstand without damage.

A contactless optical gauging machine is used to measure dimensional attributes of the device.

Ability of the device to bend in order to accommodate the predetermined clinically relevant radius or angle it will be required to negotiate during access and delivery.

The purpose of this test is to assess the lubricity and the durability of hydrophilic coatings (on balloons, catheters etc). The most common test used for finding friction at a surface is a pinch test, where test samples are pinched between two plates (pads) with a known amount of force or a defined distance, while using a motor to pull and/or push the test article through the plates. The force it takes to pull and/or push the device through can be measured. Passing the device through the pinch test multiple times will eventually cause the coating to fail and friction readings to increase.

Uses both the proximal and distal load cell to measure the amount of force applied on the device and a specific accessory during retraction.

Determine the kink resistance of a single lumen catheter or medical tubing for short term (< 1h) or long term (> 1h) use.  Kink is defined when the bending causes a decrease in flow by more than 50 %.

Catheter hubs are checked for leaks by applying constant pressure.

Tensile test (uniaxial) to determine the bond strength at locations where adhesives, thermal fusion, or other joining methods are used for bonding components of the delivery system.

Ensure the distal tip of crimped stent remains in contact with the balloon at all times, while navigating through a tortuous path. The degree of flaring of the stent away from the balloon is measured.

Pushability uses the proximal and distal load cell to measure the amount of force the distal tip of the guidewire sees when a known force is being applied to the product on the proximal end.

Test specimens are exposed to X-Ray levels necessary for the imaging system and the product or material. Digital analysis method is used to produce the images in accordance with the equipment manufacturer’s instructions. Radiopacity of the device is determined by qualitatively comparing X-ray image(s) of a test sample and a user-defined standard with or without the use of a body mimic.

A customer-defined number of revolutions is applied to the proximal end of a device with a customer defined step. At each step, the corresponding rotation at the distal end is measured by direct reading on the distal measurement system and then recorded. The tests can be performed in straight path or in a predefined arterial model.

Before conducting other evaluations, test samples should undergo all the steps a finished device would go through before being implanted in the patient.

Uses the roller system and the camera to qualitatively evaluate the performance of the device using a tortuous path that simulates the intended use conditions.

Devices can be subjected to various physiological pulsatile flows and pressures.

A catheter is deployed over a guidewire. The catheter is removed and guidewire must be left in place. Special case of Simulated use testing.

The rigidity of catheter, stent, or endovascular device is measured using a three point deflection method. The sample rests perpendicular to two lower static supports, with an applied deflection site centered between them. A displacement is applied at a fixed rate while measuring the resultant force. The test stops when the displacement reaches 0.2 x span length.

Rotate the proximal end of the catheter while the distal end is fixed and routed through a tortuous anatomy. The number of turns to failure is recorded.

Measure of the amount of torque transmitted through the guidewire. Also known as Torque Response.

The purpose of this test is to determine the torque required to cause failure of the joints and/or fixed connections in the catheter system.

Trackability uses the proximal load cell to measure the force to advance the device through a tortuous anatomy with or without the aid of a guiding accessory such as a guidewire, guide catheter, etc.

Withdrawbility involves retracting or re-sheathing the medical device as part of simulated use testing to determine the ability to withdraw.