When arteries in the heart become blocked due to coronary artery disease, one of the ways to treat it is through the use of a coronary stent. These are tubular support devices that can be surgically implanted into the coronary arteries to keep them open, allowing the arteries to supply blood to the heart properly. Over the last ten years, stents have become one of the most commonly implanted medical devices, and the process to place the stent into the body is only minimally invasive.
To ensure the safety and efficacy of every stent, rigorous testing is critical. In fact, the United States Federal Drug Administration (FDA) recommends that stents must be able to withstand 10 to 15 years of pulsatile loading in the human body, or in vivo. This equates to roughly 400 to 600 million heart pulses, or loading cycles. From a quality control perspective, this demands that stents be tested to ensure they can withstand exhaustive loading and unloading of up to 600 million cycles, which is outlined in ASTM 2477. When it comes to stent testing, this type of rigorous pulsatile fatigue testing often receives the most attention, but in fact, many other mechanical tests are performed throughout the design and quality control process. Raw material characterization, stent design selection, component testing, and stent deployment characteristics must also be evaluated to ensure a stent will safely and effectively help a patient survive.