Deutsches Herzzentrum München und Deutsches Zentrum fur HerzKreislaufforschung e.V., München, Germany.
EuroIntervention. 2018 Oct 12;14(9):e1040-e1048. doi: 10.4244/EIJ-D-17-00708.
Because vascular restoration therapy using bioresorbable vascular scaffolds (BRS) remains an appealing concept to restore vasoreactivity, an understanding of biodegradation remains paramount during preclinical testing. We therefore aimed to investigate the qualitative and temporal course of degradation of magnesium alloy-based bioresorbable vascular scaffolds in juvenile swine.
Qualitative characterisation of biodegradation was performed in 41 DREAMS 1G up to three years, while degradation kinetics were acquired in 54 DREAMS 2G implanted into porcine coronary arteries for 28, 90 and 180 days, one and two years. Assessment of end product composition was achieved in DREAMS 2G at 180 days. Myocardium was examined, while an OCT attenuation score was derived at strut level from 180 days to two years in DREAMS 2G. Degradation of DREAMS entails two corrosive phases. At one year, 94.8% of the magnesium was bioabsorbed in DREAMS 2G and, at two years, magnesium was completely replaced by amorphous calcium phosphate. Von Kossa staining revealed variable peri-strut mineralisation at all time points and only small focal myocardial emboli observed in one animal in the 180 days cohort. Strut discontinuity density was low at 28 days (0.5±0.57 per mm) and increased to a density above 7.5 per mm up to one year. OCT attenuation score correlated well with strut-based degradation analysis up to two years.
While the current set of data supports vascular safety, clinical trials are warranted to prove the concept of vascular restoration following DREAMS implantation.
由于使用生物可吸收血管支架（BRS）进行血管修复治疗仍然是恢复血管反应性的一个有吸引力的概念，因此在临床前测试中，对降解的理解仍然至关重要。因此，我们旨在研究幼年猪体内基于镁合金的生物可吸收血管支架的定性和时间降解过程。
在 41 个 DREAMS 1G 中进行了定性降解特征研究，最长可达 3 年，而在 54 个 DREAMS 2G 中进行了降解动力学研究，将其植入猪冠状动脉中 28、90 和 180 天、1 年和 2 年。在 180 天时对 DREAMS 2G 进行了最终产物组成的评估。检查了心肌，同时在 DREAMS 2G 中从 180 天到 2 年，在支架水平上得出了 OCT 衰减评分。DREAMS 的降解涉及两个腐蚀性阶段。在 1 年时，DREAMS 2G 中 94.8%的镁被生物吸收，在 2 年时，镁完全被无定形磷酸钙取代。Von Kossa 染色显示所有时间点的支架周围均有不同程度的矿化，仅在 180 天队列的一只动物中观察到少量局灶性心肌栓塞。在 28 天时，支架不连续性密度较低（0.5±0.57/毫米），并在 1 年内增加到超过 7.5/毫米。OCT 衰减评分与支架降解分析的相关性在 2 年内都很好。
虽然目前的数据支持血管安全性，但需要进行临床试验来证明 DREAMS 植入后血管修复的概念。
