Geometric adaption of resorbable myocardial stabilizing structures based on the magnesium alloys LA63 and ZEK100 for the support of myocardial grafts on the left ventricle

Abstract

Damage of the heart muscle's tissue is irreversible due to the inability of adult cardiomyocytes to proliferate. Biological grafts like vascularized bowel segments are a novel approach to overcome these limitations. We found cardiac muscle cells within the heterotopically used gastric tissue in previous studies [1]. This may indicate an in vivo remodeling process. Unfortunately, early after transplantation the biological tissue does not exhibit sufficient mechanical strength to withstand high systolic pressures in the left ventricle (up to 240 mm Hg). Therefore, a stabilizing structure based on the bioresorbable magnesium alloys is needed for the support of the tissue until its physiologic remodeling. It is hypothesized that preformed structures adapted to the specific geometry of the targeted myocardial area are less likely to fracture during implantation or shortly after. In order to preform the structure, common areas of lesioned myocardium after infarction have been characterized by magnetic resonance imaging (MRI). Hereafter, the plane structures could be virtually preformed and the expected stresses were simulated with the finite elements method (FEM). This allows reduction of costs and time for developing new structures. Subsequently, structures of the magnesium alloys LA63 and ZEK100 were manufactured by abrasive water injection jet cutting (AWIJ), and preformed on the basis of the MRI data. Finally, the performance of preformed and non-preformed structures of different alloys was tested in an in-vitro testing rig. © 2012 by Walter de Gruyter. Berlin. Boston.