Cardiovascular Stent
A cardiovascular stent can be placed in a coronary artery of the heart if atheroma is diagnosed. Atheroma is the medical definition of fatty deposits that can build up inside vascular walls during the process that is called atherosclerosis. This causes a narrowing of the artery and reduced blood flow. If this is the case, a stent can be placed via a catheter in the coronary artery. If the stent is in position a small balloon inside it can be inflated. During the inflation the stent will deform and get a slightly larger diameter and will thus eliminate the restriction of blood flow. The stent will stay in the coronary artery after this.
Inflation of stent
The result was a good understanding of response of the stent on the inflation, and the behaviour if the dimensions of the thin metal wires were varied. The areas with most deformation were understood. Especially in the sharp corners the material undergoes stress. By varying the thickness of the wires slightly, at different pre-inflation diameters, the location of plastic deformation could be assessed. The specifications were assessed accurately, and as a consequence the rate of defects could be halved in the production process.
Stent deployment
Simulate the deformation during the inflation of the balloon. These analyses were done on a new design of stents for Biosensors International. Determine the areas with most plastic deformation. Assess with Finite Element Analysis the permanent deformation after the balloon is removed.
The materials used for a stent has to comply with the highest standards. The stent had to be modelled in the software in 3D and the inflation of the balloon was added as a load to measure the deformation during the stent placement. Several inflation scenarios with corresponding geometric values were simulated. For every geometric variation the permanent plastic deformation was calculated, an important physical quantity.