The heart can be compared to a muscular pump, which maintains the blood circulation with sixty to eighty contractions per minute. That means nearly 2.5 billion contractions during the life. Understanding this huge number is not easy, but more important that this process should be performed without intermission. A cardiac arrest leads to death within a very short period of time. The continued contraction of the heart also means the continued use of the coronary arteries, so the streamline in them is very important.
In Europe, most of the deaths are due to cardiovascular diseases. During the disease a fatty, calcariferous subsidence, called plaque formation, evolve in the inner wall of the blood vessel. The stenosis, formed thereby, block the free flow of blood, which can cause long-term myocardial infarction. The stent is a biocompatible tubular mesh, which is inserted to the narrowed vessel segment. It compresses the plaque so extends and supports the vessel.
After comparing the functional properties of stents, physicians can choose the appropriate stent for patients more easily with the results. My aim is examining, evaluating and comparing these properties, and making a measurement guide to each property.
Several coronary stents were investigated, made from different metal alloys. The measured object were functional stent properties (e.g. strut width, recoil, foreshortening, metallic surface area) which apply to the stent itself; and functional stent-system properties (e.g. crossing profile, flexibility, conformability to vessel wall), which apply to the joint behaviour of the balloon catheter and the attached stent. Each measurement corresponds to the MSZ EN ISO 25539-2 standard.
The experience and the results gained during this work provide a basis to perform further research. The examination of any vasoactive properties of coronary stents gives results that can be used in practice.