Acute Particulate Testing of Stents, Stent-grafts and Catheters

Dynatek Labs performs Acute Particulate testing of a variety of vascular devices.  Acute Particulate Testing of vascular devices such as stents, stent-grafts, and stent delivery systems includes:

1. Particulate Matter Evaluation during Deployment and Withdrawal
2. Coating Integrity Inspection

Dynatek Labs provides a ‘one stop’ facility for your Acute Particulate Testing requirements.

Particulate Matter Evaluation during Deployment and Withdrawal

Particulate Matter Evaluation during Deployment and Withdrawal at Dynatek Labs references the following standards and regulations:

i. ISO 25539-2:2012 – Cardiovascular Implants – Endovascular Devices – Part 2, Vascular Stents
ii. FDA Guidance for Industry and FDA Staff – Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems, April 18, 2010
iii. FDA Guidance – Class II Special Controls Guidance Document for Certain Percutaneous Transluminal Angioplasty (PTCA) Catheters
iv. ASTM F2743-11 – Coating Inspection and Acute Particulate Characterization of Coated Drug-Eluting Vascular Stent Systems
v. AAMI TIR42:2010 Evaluation of Particulates Associated with Vascular Medical Devices

Particulate Matter Evaluation during Deployment and Withdrawal

FDA recommends that the device manufacturer is able to “demonstrate that the delivery catheter can safely and reliably deliver the stent to the intended location and that the stent is not adversely affected by the delivery catheter, both during deployment and withdrawal.”

To evaluate the effect of deployment and withdrawal on the stent, Particulate Matter Evaluation is carried out using a temperature-controlled, continuous flow, tortuous path or track in line with a laser particle counter and particle-capture filter. Dynatek can test your vascular device in the tortuous path recommended by ASTM F2394 or we can use a tortuous path that you specify. We will work with your team to understand your vascular device and design the particulate evaluation tests around it.

The device is deployed as described in the Instructions for Use (IFU) for the device. You can choose to deploy the device yourself or have our technicians deploy them following the IFU. Particles shed by the vascular device during deployment and withdrawal are counted and sized by the custom laser counter downstream of the deployment path, and then captured by a proprietary membrane disc filter seated in a sealed stainless steel housing. The filter is shipped to an outside SEM Analysis Lab, for chemical and elemental analysis of the particulates on the filter using Energy Dispersive X-ray Spectroscopy (EDX). Particulate Evaluation as described in this test is used for regulatory submission.

Coating Integrity Inspection

Coating Integrity Inspection is normally carried out by an optical microscope or a scanning electron microscope under appropriate magnification. The stent is inspected before expansion, after expansion to its nominal or maximum diameter and after simulated use. Coating integrity inspection is performed to determine delamination or degradation of a vascular device during deployment. An affiliate lab performs all coating integrity inspections for Dynatek customers, including a detailed report with images of defects, anomalies and artifacts found on the device surface.

Coating integrity inspection may organize coating defects and anomalies into several categories:

Category I – Anomalies related to coating thickness, which may be due to increased or decreased coating at any given point on the stent surface. Such anomalies may result in the exposure of bare metal in some areas or the formation of cracks, especially on the inside of curves or cause ‘blisters’ or ridges in the coating material
Category II – Non-homogenous coating may result in ‘wrinkle’ formation or ‘crater’ formation with or without metal exposure
Category III – Coating displacement may result in anomalies such as ‘webbing’ that may occur with or without metal exposure

Drug-Eluting Balloon Testing

FDA considers drug-eluting balloons to be a hybrid product that combines an interventional device and a drug.  Drug-eluting balloons are regulated by the Center for Devices and Radiological Health in collaboration with the Center for Drug Evaluation and Research as a Class III device.  With our patented particle counting and particle capture technology, Dynatek Labs can assist you with answering crucial questions relating to how much of the coating on the balloon is shed as particles before and after balloon expansion, and the effect on the coating due to multiple expansions of the balloon and the consequent shedding of particles.  The particles shed by the balloon can help evaluate the overall efficacy of the drug coating on the balloon.