Development of Magnesium Alloy Scaffolds to Support Biological Myocardial Grafts: A Finite Element Investigation

Abstract

Lesioned myocardial tissue can be replaced with innovative biological grafts. However, the strength of most biological grafts is initially not sufficient for left ventricular applications. Implants that mechanically support these grafts and gradually lose their function as the graft develops its strength are a possible solution. We are developing magnesium alloy scaffolds for this purpose. The finite element method was used to perform simulations wherein scaffolds are deformed according to the heart movement. This allows us to identify highly stressed regions within the implant that need design changes. Preformed scaffolds were determined to have significantly lower stresses in comparison to flat ones. The method of tensile triangles suggests shape changes for notable stress reduction. Furthermore, new scaffold shapes were developed and simulated. Two of them are recommended for further examinations through in vitro and in vivo tests. A completely new alternative scaffold concept is also proposed.

Biomedical Materials and Devices with Focus on Orthopaedic and Cardio-vascular Problems

“…They usually consist of a net with the possibility to extent or contract by for example, temperature or forces acting from outside. The most common use for coronary stents is in the coronary arteries, into which a bare-metal stent, a drug-eluting stent, a bio-absorbable stent, a dual-therapy stent (combination of both drug and bioengineered stent), or occasionally a covered stent is inserted [7][8][9]. Vascular stents made of metals can lead to thrombosis at the site of treatment or to inflammation scarring.…”

“…Because of the external compression and mechanical forces subjected to these locations, flexible stent materials such as nitinol (Ni-Ti-alloy) are used in a majority of peripheral stents. Also, bio-resorbable Mg-alloys are used if an only temporary presence of the stent is needed [6][7][8].…”