Stent Graft Testing and Vascular Prosthesis Testing

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. 

Pressure at which the prothesis bursts.

Pressure at which the prothesis bursts using a balloon to seal devices with high permeability which may not be able to hold pressure on their own.

A probe is traversed through the specimen until it ruptures.

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

Evaluate the strength of the connection of the graft to the stent structure.

Determination of the radius of curvature required to begin “kinking” a vascular prosthesis.

Force required to displace the prosthesis within a mock artery.

Measure the area of the voids and/or the area of the material on the sample prosthesis by means of measurements made on a scanning electron micrograph or optical micrograph.

Determination of internal diameter under simulated physiological conditions of the same order of magnitude as the arterial blood pressure: 120 mmHg.

The force-diameter curves of stent like structures are determined while loading and unloading the sample according to a specified profile.

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.

The relaxed internal diameter of the test device is measured.

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

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

Determination of the force necessary to pull a suture from the prosthesis or cause the wall of the prosthesis to fail.

Circumferential Tensile Strength – Sample prosthesis in its tubular form is placed onto two rounded pins and stretched at a uniform rate until the yield and/or break point is reached.

Longitudinal Tensile Strength – A sample of the prosthesis in its tubular form is placed with its ends in suitable jaws. It is then stretched at a uniform rate until the yield and/or break point is reached.

Stent expansion uniformity: Difference between the largest and smallest diameter measurement on a single stent deployed to its labelled diameter.

The usable length of the prosthesis is measured under a tensile load.

Determination of the thickness of the wall of the prosthesis under no load or minimal load. A microscope with direct and diffuse illumination is used.

Pressure at which water is observed on the external surface of a pressurized sample.

Determination of the rate of flow of water through a given area of the sample or the entire prosthesis under a given hydrostatic pressure.