Knowledge Base

Medical Device Testing Standards

 

Dynatek’s products are designed to fulfill current and anticipated international regulations. Learn more about how our machines satisfy the following standards:
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  • ISO 5840-1:2015

  • ISO 5840-2:2015

  • ISO 5840-3:2013

  • ISO 7198:2016

  • ISO 12417-1:2015

  • ISO 14708-5:2010

  • ISO/TS 17137:2014

  • ISO 25539-1:2017

  • ISO 25539-2:2012

  • AAMI TIR42:2010

  • ASTM F2394 – 07(2017)

  • ASTM F2477-07

  • ASTM F2743-11

  • ASTM F3036-13

  • ASTM WK46148

  • ASTM WK60510
  • ASTM WK60511

Dynatek’s innovations list continues to grow.

 

Dynatek First

  • First commercially available vascular graft durability tester.
  • First to introduce dynamic internal compliance.
  • First to create velocity flow standard.
  • First to use tuned fluid oscillation to test heart valves.
  • First in the use of precise mock arteries.
  • First to use 5% to 7% compliance.
  • First to develop a commercially available pulsatile artificial heart tester.
  • First to develop precise high-speed photographic verification protocols and procedures.
  • First commercially available coating durability tester.
  • First to develop technology for acute particulate testing.
  • First to develop fatigue to fracture testing.

Radial Pulsatile Durability Testing, Coating Durability and Bend Testing of Stents and Stent Grafts

Radial pulsatile durability testing is performed in our contract testing lab on one of several proprietary test platforms listed above, to evaluate the long-term mechanical integrity of the stent or stent graft under pulsatile cyclic loading conditions.

A wide range of stents and stent grafts from 2 mm to 50 mm ID can be tested on our radial pulsatile durability testers.  Stents are mounted in mock silicone vessels that are manufactured in our silicone vessel facility.  These mock silicone vessels can be straight, curved or bifurcated, and are made to virtually any range of compliance that our customers require for radial fatigue testing of stents.  As mentioned above, very large vascular prostheses such as abdominal aortic aneurysm (AAA) stent grafts and thoracic aortic aneurysm (TAA) stent grafts with IDs of up to 50 mm are routinely tested for radial pulsatile durability at Dynatek.

Heart Valve Durability Testing at Dynatek’s Contract Testing Lab

With 28 years of experience in heart valve testing, Dynatek Labs leads the world in heart valve testing that meets ISO 5840 requirements. In addition to this decades-long experience in heart valve prosthesis testing, Dynatek Labs and our customers benefit tremendously by Dr. Jim Conti’s participation in ISO/AAMI/ASTM standards committees. Dr. Conti’s participation in the activities of the standards committees gives Dynatek Labs significant insight and understanding of the regulatory framework as it impacts heart valve prosthesis testing. Customers who have their heart valve devices tested in Dynatek’s contract testing lab benefit from understanding exactly what tests are required by regulatory bodies, and how to accomplish the test objectives in the most cost-effective manner.

Acute Particulate Testing of Stents, Stent-grafts and Catheters

ASTM and ISO regulations drive the acute phase particulate testing of medical devices destined for use in the human vasculature. Acute Particulate Testing of vascular devices such as stents, stent-grafts, balloons, occluders, and 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.

Custom Capabilities

30 years and thousands of samples after opening, Dynatek Labs has often found that the unique features of your stent, heart valve or other cardiovascular (CV) device may not lend themselves to an off-the-shelf testing solution. In fact, while AAMI/ISO, FDA and ASTM regulations spell out the objectives of the test, developing an appropriate test, test fixture or test protocol for unique cardiovascular devices can be very challenging even for established cardiovascular companies.

No one tests faster than we do!

ISO, ASTM and FDA regulations require the testing of stents and stent grafts for at least 380 million cycles.  At physiological speeds of 72 beats per minute (1.2Hz), it would take one month for 3.1 million cycles of testing, or literally 10 years to meet the regulatory requirements.  To meet the regulatory requirements of 380 million cycles, regulatory agencies allow testing at accelerated speeds, leading to shorter test periods, and significantly lower testing costs.

 

 

 

Sizing Matters

Correct sizing of mock vessels is crucial to the validity of a cardiovascular stent test. Dynatek mock vessels are tested and certified for compliance and wall thickness.

 

 

Acute Particulate Testing of Stents, Stent-grafts and Catheters

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

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

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

 

Critical Criteria For Purchasing a Heart Valve Tester

Heart Valve Testers are complex instruments and investing in these units can be expensive, time consuming and fraught with risk. This buyer’s guide provides both technical information that pertains to these devices, as well as the regulatory framework within which they are used. The key to choosing the right heart valve tester is making sure that the tester features the right technology to thoroughly test your heart valve or cardiac device for durability and fatigue, meets performance criteria as mandated by AAMI/ISO/FDA regulations, and does so in the most cost-effective manner.

Flow-Through in Stent Radial Fatigue and Coating Durability Testers

Stents undergoing testing need to experience pulsatile pressurization at a uniform temperature. To pressurize the mock vessel and the device deployed inside it, a test solution (e.g., a buffer like phosphate buffered saline) is used.

When a non flow-through instrument is used to pressurize the mock vessel and stent, the fluid flows into the proximal end of the mock vessel, fills it up and pressurizes it in a pulsatile fashion, without the fluid in the mock vessel flowing out the distal end of the vessel. The fluid in the non flow-through method of testing is at a known temperature and therefore it is assumed that the stent is at, or close to, that temperature.

High Speed Photographic Verification of Stent Deflection

Durability or fatigue testing of stents and stent-grafts involves the deployment of the vascular device into a compliant silicone mock vessel which undergoes pulsatile deflection on the test platform.

To evaluate high speed photographic verification of stent deflection, researchers at Dynatek used the DCT Dynamic Compliance Tester (Fig.1) and a FastCam PCI 1280 High Speed Camera (Fig.3). An intravascular stent graft (8cm long) was deployed in a compliant silicone mock vessel (28.12 mm OD; 22.55 mm ID). The dimensions of the silicone mock vessel were measured using a laser micrometer.

M6 Heart Valve Tester Demonstration

A full hands-on demonstration of the M6 will be given to you, using Dynatek’s test sections with mechanical valves. The demonstration will cover the working of the testing chamber, the pump unit, controller and theory of operation. In-house mechanical valves will be mounted in the test sections to demonstrate the functioning of the M6.

The Full Product Demonstration is free of charge and usually lasts about 4-6 hours, including time to address all of your questions. In addition to the product demonstration, we also offer two options where you can actually test your own valve candidates on the M6, gaining valuable ‘real world’ data about them.

Particle Counters for Stent Testers

According to ASTM regulations1 on particulate characterization of coated drug-eluting vascular stent systems, the capture and analysis of particulates shed by intravascular devices may be performed in two ways:

a. Particles released may be captured in a receptacle and subsequently sampled for count/size using light obscuration or filtration/microscopy, or

b. Particles released may be acquired and continuously counted in an apparatus designed to direct flow exiting from the stent/tube assembly directly into a particle counter1.

Particulate Capture from Vascular Stents

According to AAMI1, there are two broad sources of particulates associated with vascular medical devices:

i. Particulates from materials and manufacturing processes. Raw materials that may undergo operational processes such as grinding, polishing, and cutting may also be a source of particulates.

ii. Particulates from the environment. Airborne particles and particles shed by personnel are controlled by HEPA-filtered air and appropriate garb and personnel practices.

Radial Fatigue Testing of Vascular Stents: Single- vs. Double-Ended Pressurization

Stents and stent-grafts are routinely tested in vitro by deployment in silicone mock vessels. Accurate radial fatigue testing of these vascular devices depends on two factors:

a. The frequency response characteristics of the mock vessel and device, and
b. A consistent cyclic load applied by the mock vessel on the device.

Cyclic load is transmitted uniformly to the device only if the mock vessel undergoes symmetric expansion around its entire circumference with every load cycle. For consistently accurate radial fatigue testing of stents, it is critical that all points on the entire length of the mock vessel that contains the stent or other device undergo the same deflection and cyclic load with every pulse.

SEM Analysis of Particles

ISO/AAMI recommends two methods for the analysis of particulates shed by vascular stents and stent-grafts, balloons and delivery catheters in liquids:

i. Light obscuration, and
ii. Microscopic analysis1

Dynatek’s patented CDT-5 and CDT-20 Coating Durability Testers and the patent pending Acute Phase Tester feature particle counters that utilize the light obscuration method to count particles shed by vascular devices into liquids. For more information on the CDT’s particle counters, see Reference 2.

Stent Radial Fatigue Testers: Now users have a choice.

While the SVP-24 tester proved to be a very successful workhorse, our customers asked for a tester that can accommodate a larger range of sample diameters, from 2 to 50 mm ID. Some companies offer separate testers for each ID size range from 2 to 50 mm ID, compelling you to purchase two or more radial fatigue testers at a very significant upfront cost, to enable you to test all of the sizes in your sample development pipeline. Dynatek took a different approach that lowers your cost of ownership and offers the widest range of sample test sizes in one platform by any vendor in the world.

Straight Mock Vessels Bent to Radius vs. Curved Mock Vessels

Mock vessels are routinely used to test the long-term durability of stents and stent grafts. The compliance and shape of mock vessels are directly responsible for the effectiveness of radial fatigue testing of stents deployed inside them. Mock vessels apply a load on stents being tested and the compliance of the mock vessel determines this load. The compliance of the mock vessel is defined as radial distension over a pressure differential. To more closely mimic in vivo structures of the coronary artery, stents that have been tested in straight vessels are increasingly being tested in curved mock vessels.

Test Sections for the M6 Heart Valve Tester

Test sections are normally made of acrylic or polycarbonate. Both of these materials are highly amenable to fabrication by CNC machines. CNC machining allows us to fabricate test sections with intricate shapes and ultra-tight tolerances. Many test sections feature ports, O-rings, gaskets and other fittings, and CNC machining allows more precise drilling, boring, thread milling and reaming operations on our test sections to provide such fittings.

 

Universal Controller for the M6

Although the monitoring and control aspects of the UC are impressive, perhaps of equal or greater importance is the time saved setting up or monitoring the “95/5” requirements for the closing pressure of each valve. The UC can accept 12 pressure transducers, two for every position in the M6. When using all 12 transducers, each valve can be tested simply by choosing each sequentially – no need to change the position of the transducer after each valve is checked.

 

 

 

 

Dynatek Labs, Inc.
105 East 4th Street
Galena, MO 65656
417.357.6155
800.325.8252
fax 417.357.6327