Stents are used to unblock clogged arteries and help restore normal blood flow. These stents may be balloon-expandable or self- expanding and may be made from various different materials such as Cobalt chromium (CoCr), Stainless Steel (SS), nitinol (NiTi), bioresorbable (BRS). A number of methods are used to ensure these devices demonstrate safety, efficacy, and quality, while performing according to their intended use and labeling. We offer comprehensive stent testing services in accordance with ISO standards, ASTM Standards, FDA guidance documents, and the latest peer reviewed research.
ViVitro Labs is a leader in providing standardized as well as customized methods for cutting edge or novel stent designs.
For catheter based delivery systems see additional tests here.
For Stent Graft and Vascular Prosthesis see additional tests here.
Acute Particulate Matter Evaluation
Conformability to Vessel Wall
Crush Resistance - Parallel Plates
The goal of the test is to determine the load required to cause clinically relevant buckling or a deflection equivalent to a diameter reduction of at least 50%, and determine the load and the displacement required to permanently deform or fully collapse the stent. The purpose of the test is to also determine whether the stent recovers from its original geometry after testing.Learn more
Crush Resistance - Pressure Control
Crush Resistance - Radially Applied Load
Using a constant displacement a radial load is applied to the sample. Force-diameter curves of stent like structures are determined while loading and unloading the sample according to a specified profile.Learn more
Direct Longitudinal Compression
Dislodgment Force - Stent Securement
Flexibility / Kink Resistance
The purpose of this test is to determine the deformation of the device in response to a localized compressive force perpendicularly applied to the longitudinal axis of the device, and to determine whether the stent recovers its original geometry after testing.Learn more
Percent Solid Area
The reference area is the full cylindrical side surface area for the stent expanded to the labeled diameter (∏ X outside diameter X length at labeled diameter). The solid area is estimated by CAD software. The solid area is determined on unexpanded stents and assumed not to change significantly during expansion. The percent solid area is the ratio of the solid area to the reference area and is reported as a percentage.Learn more
Profile Effect / Flaring
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.Learn more
Radial Fatigue and Pulsatile Durability
Radial Force Measurement
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.Learn more
Scanning Electron Microscopy (SEM) and Optical Inspection
Simulated Use Pre-conditioning
Simulated Use Testing Under Pulsatile Flow
Stent System Compliance
For balloon-expandable stents, a table of inflation pressure versus expanded diameter is developed and included in the labeling. The expanded stent inside diameter at each inflation pressure is the mean of all measurements taken on all stents at that pressure. The inflation pressure is expressed in atmospheres.Learn more
Strut and Bridge Thickness
Strut and bridge thicknesses of the expanded finished stent are measured by direct measurement using a calibrated optical system. Strut and bridge thickness are measured at the stent mid-length and near each end, at two circumferential locations at each axial location. If strut and bridge thicknesses are systematically different by design, they will be measured and reported separately. Direct measurement may require test samples destruction by cutting, or flattening, or both.Learn more
Uniformity of Expansion / Dog Boning Effect
ISO 25539-1:2017 Cardiovascular implants — Endovascular devices — Part 1: Endovascular prostheses
ViVitro Labs provides stent testing services such as dimensional verification of the endovascular system, dislodgement force (pre-mounted, balloon-expandable endovascular prosthesis), force to deploy for self-expanding endovascular prostheses, simulated use, corrosion, fatigue, durability, radial fatigue, radial durability, fixation and seal evaluation, leakage at seal zone, migration resistance, separation force for overlapping endovascular prostheses, patency-related (crush resistance, local compression, and radial force), compression
resistance to perpendicularly applied load, crush resistance with perpendicularly applied load, Crush resistance with radially applied load, radial force.
ISO 25539-2:2020 Cardiovascular implants —Endovascular devices —Part 2: Vascular stents
ViVitro Labs provides stent testing services such as dogboning, dimensional verification, acute particulate generation, profile effect/flaring, simulated use, tensile bond strength, torsional bond strength, visibility (radiopacity) , corrosion, radial fatigue, radial durability, patency-related (crush resistance, local compression, and radial force), compression resistance to perpendicularly applied load, crush resistance with perpendicularly applied load, Crush resistance with radially applied load, radial force, kink resistance (flexibility) stent-free surface area and stent outer surface area, dimensional verification of test, stent diameter to balloon inflation pressure, stent length, recoil.
FDA-1545 FDA Guidance: Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems – Guidance for Industry and FDA Staff
ViVitro Labs provides stent testing services such as stent corrosion resistance (fretting corrosion, pitting and crevice corrosion potential, galvanic corrosion), dimensional verification, percent surface area, foreshortening, recoil, stent integrity, radial stiffness, radial strength, radial outward force, fatigue, accelerated durability testing, particulate evaluation, radiopacity, crush resistance , kink resistance, stent securement.
For catheter based delivery systems see additional tests here.
ASTM F2477 – 19 Standard Test Methods for in vitro Pulsatile Durability Testing of Vascular Stents