Structural heart occluders are used to close heart defects, openings, or appendages. Our occluder device testing services assess durability with low and high cycle testing to ensure safety for patients.
Transcatheter structural heart repairs have largely replaced open-heart surgery. During percutaneous closure of defects, the occluder device is attached to a catheter, inserted into a vein in the groin, and advanced to the heart and through the defect. The device is then pushed out of the catheter so that it covers each side of the defect, thereby closing it. When in the proper position, the device is released from the catheter, and the catheter is retrieved. Heart tissue may grow into and over the implant over time.
Occluder device indications
There are several defects, openings, or appendages that may require a closure procedure with an occluder device. These conditions include:
- Atrial septal defect (ASD): a hole in the wall between the atria
- Ventricular septal defect (VSD): a hole in the wall between the ventricles
- Patent foramen ovale (PFO): when the foramen ovale does not close spontaneously postnatally
- Patent ductus arteriosus (PDA): when the ductus arteriosus does not close spontaneously postnatally
- Left atrial appendage (LAA): prone to clot formation and increased risk of stroke in patients with atrial fibrillation
Low cycle and high cycle fatigue testing for occluder devices
Low cycle occluder device fatigue testing is performed by repeated deployment and retrieval of the device in a simulated use geometry setup to simulate initial device malposition and need for re-deployment. High cycle durability testing demonstrates the device’s ability to withstand physiological stresses during long term implantation.
Many occluder devices are composed of a braided metal-based support frame and may include a polymer or fabric mesh. The braided design often puts more emphasis on testing these devices for fretting wear and fretting corrosion.
Due to the typical device design of two disks that flank the cardiac defect, testing focuses on the “waist” of the device that connects the two disks, as the “waist” tends to bear most of the loading when in use. Element’s expertise in durability testing of occluders and closure devices assists manufacturers in developing test protocols and inspection methods well-suited for even the most challenging device designs.
Occluder device accelerated durability testing
We perform pulsatile fatigue testing with our ElectroForce 9100 stent series test instruments for 40 million to 600 million cycles. Feasibility tests typically target 40M cycles while full regulatory submission tests run for 400M or 600M cycles. Axial fatigue testing in tension or bending is done on ElectroForce 3200 or 3300 test instruments depending on the number of specimens and required displacements. Our Occluder and Closure Device Fatigue Testing article outlines pulsatile and axial fatigue test protocols.
During testing, device failure is defined by the device manufacturer who will also examine the devices post-testing against pre-defined acceptance and failure criteria. We inspect the device before, during, and after testing at predetermined intervals.
The Element advantage
Our Engaged Experts excel at cardiovascular device testing and have worked with many challenging device designs and test setups over the last several decades. Contact us to discuss how we can help with your test project.
Standards we test to
While there are no specific standards for occluder device testing, the standards below cover aspects of occluder and closure device testing:
- ISO 5840-1 Cardiovascular implants – Cardiac valve prostheses – Part 1: General requirements
- ASTM F2477 Standard Test Methods for in vitro Pulsatile Durability Testing of Vascular Stents
- ISO 25539-1 Cardiovascular implants – Endovascular devices – Part 1: Endovascular prostheses
Additionally, the FDA guidance document titled “Non-Clinical Engineering Tests and Recommended Labeling for Intravascular Stents and Associated Delivery Systems – Guidance for Industry and FDA Staff” contains information pertinent to in vitro occluder testing.
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