Resorbable magnesium scaffolds are used for the treatment of atherosclerotic coronary vascular disease and furthermore, for vascular restoration therapy. Recently, the first-in-man clinical studies with Magmaris showed promising results regarding the target lesion failure as well as vasomotion properties after 12 and 24 month. The consistency of in vivo degraded magnesium alloys in a cardiovascular environment is qualitatively described in literature, but only little has been disclosed about the actual change in mechanical properties and the behavior of the magnesium alloy degradation products.

In the present study, uncoated magnesium scaffolds 3.0 × 20 mm were implanted in coronary arteries of two healthy Goetinnger mini-swine. The scaffolds were explanted to evaluate the mechanical properties of the degraded magnesium scaffolds after 180 days in vivo. Ex vivo sample preparation and test conditions were adapted to a customized compression test setup which was developed to investigate the micro-scale scaffold fragments (width 225 ± 75 µm, thickness 150 µm). As reference bare undegraded magnesium scaffold fragments were tested. Mechanical parameters relating to force as a function of displacement were determined for both sample groups.

The undegraded samples showed no fracturing at the maximum applied force of 8 N, whereas the in vivo degraded test samples showed forces of 0.411 ± 0.197 N at the first fracturing and a maximum force of 0.956 ± 0.525 N. The deformation work, calculated as area beneath the force-displacement curve, of the in vivo degraded test samples was reduced by approximately 87–88% compared to the undegraded samples (5.20 mN mm and 40.79 mN mm, both at 7.5% deformation).

The indication for a complete loss of structural integrity through a reduction of mechanical properties after a certain degradation time increases the chance to restore vascular function and physiological vasomotion in the stented vessel compartment.

可吸收的镁支架用于治疗动脉粥样硬化性冠状血管疾病，并且还用于血管修复治疗。最近，与Magmaris进行的首次人体研究表明，在12个月和24个月后，有关目标病变失败以及血管舒张特性的研究结果令人鼓舞。在心血管环境中定性描述了体内降解镁合金的稠度，但是关于机械性能的实际变化和镁合金降解产物行为的披露很少。

在本研究中，将3.0×20 mm的未涂层镁支架植入两只健康的Goetinnger小型猪的冠状动脉中。植入支架以评估体内180天后降解的镁支架的机械性能。离体样品制备和测试条件适应于定制的压缩测试装置，该装置被开发用于研究微型支架碎片（宽度225±75 µm，厚度150 µm）。作为参考，测试了未降解的裸镁支架碎片。对于两个样品组都确定了与力作为位移函数的机械参数。

未降解的样品在最大施加力为8 N时没有破裂，而体内降解的测试样品在第一次破裂时显示的力为0.411±0.197 N，最大力为0.956±0.525N。按面积计算的变形功在力-位移曲线下方，与未降解的样品（5.20 mN mm和40.79 mN mm，均在7.5％变形下）相比，体内降解的测试样品减少了约87–88％。

在一定的降解时间后通过降低机械性能完全丧失结构完整性的迹象增加了在支架血管腔内恢复血管功能和生理血管运动的机会。