Finite element analysis for stent in patent ductus arteriosus (PDA)

Patent ductus arteriosus (PDA) complication can pose several problems to neonates. Practices that use commonly available stents for neonates have been shown to generate others problems such as re-stenosis and thrombosis formation. Thus, there is a need to introduce a specialized stent for PDA application. In this study, initial effort to design a PDA stent has been started. Investigations were focused on the effect of flow dynamics to the failure of the stent inserted into the PDA. Load effects on stent were modeled using finite element modeling software. Unsteady flow effects including both systolic and diastolic conditions were used to mimic physiological conditions. Stress distributions on the stents struts are analyzed to determine critical area of high stress. Several types of stent including slotted stents and diamond shape stent were used for comparisons. The materials of stents are stainless steels 316L and Cobalt-Chromium L605. The results show that blood flow only contributes to 10–15 percent of the total stress required for the stent to fail. Distribution of the stresses was found to be highest in the area of joints of the struts for all types studied. The ratio of the maximum stress experienced by the struts to the minimum was roughly double. Comparing all the stresses experienced by the stents, the slotted stent was found to the most susceptible to least favorable.