Shape and functional optimization of biodegradable magnesium stents for manufacturing by ultrasonic-microcasting technique

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In this study, a well-known stent model, Palmaz–Schatz, and a new geometry, NG, are optimized, in agreement with a set of optimization variables and limiting values of the design parameters, imposed by a new manufacturing process—ultrasonic-microcasting—, which allows to surpass some difficulties presented by other manufacturing technologies. The optimized designs shown that significantly lower values of the considered performance parameters can be obtained, namely in terms of required expansion pressure, which was reduced 30.31% for Palmaz–Schatz stent and 55% for NG stent. Dogboning and foreshortening were minimized and a reduction of 97.30 and 86.64%, respectively, was achieved for Palmaz–Schatz model, while for NG model such values were 13.64 and 50.00%. Despite the greater values of thickness comparing to the stainless-steel devices (0.30 vs 0.10 mm), the optimized stents studied present a similar or even better performance than those. Furthermore, results suggest that the adopted optimization methodology can effectively optimize the stent’s design and their functionality for devices to be manufacturing by the ultrasonic-microcasting processing. The presented optimization methodology allows the interaction between the requirements imposed by the patient’s condition, i.e. the initial and expanded diameter of the stent and its length, and the constraints imposed by the manufacturing process, having as result the optimal geometry regarding the defined objectives.