Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA.
Insilicomed, La Jolla, CA, USA.
Artif Organs. 2021 Sep;45(9):E335-E348. doi: 10.1111/aor.13974. Epub 2021 May 17.
Despite the increasing incidence of heart failure, advancements in mechanical circulatory support have become minimal. A new type of mechanical circulatory support, direct cardiac compression, is a novel support paradigm that involves a soft deformable cup around the ventricles, compressing it during systole. No group has yet investigated the biomechanical consequences of such an approach. This article uses a multiscale cardiac simulation software to create a patient-specific beating heart dilated cardiomyopathy model. Left and right ventricle (LV and RV) forces are applied parametrically, to a maximum of 2.9 and 0.46 kPa on each ventricle, respectively. Compression increased the ejection fraction in the left and right ventricles from 15.3% and 27.4% to 24.8% and 38.7%, respectively. During applied compression, the LV freewall thickening increased while the RV decreased; this was found to be due to a change in the balance of the preload and afterload in the freewalls. Principal strain renderings demonstrated strain concentrations on the anterior and posterior LV freewall. Strains in these regions were found to exponentially increase after 0.75 normalized LV force was applied. Component analysis of these strains illuminated a shift in the dominating strain from transmural to cross fiber once 0.75 normalized LV force is exceeded. An optimization plot was created by nondimensionalizing the stroke volume and maximum principal strain for each compression profile, selecting five potential compression schemes. This work demonstrates not only the importance of a computational approach to direct cardiac compression but a framework for tailoring compression profiles to patients.
尽管心力衰竭的发病率不断上升，但机械循环支持方面的进展却微乎其微。一种新型的机械循环支持方式，即直接心脏压缩，是一种新颖的支持模式，它涉及围绕心室的柔软可变形杯子，在收缩期对其进行压缩。目前还没有任何一个团队研究过这种方法的生物力学后果。本文使用一种多尺度心脏模拟软件为一个特定的扩张型心肌病患者创建了一个跳动心脏模型。通过参数化的方式在左心室和右心室上施加力，最大可达每个心室 2.9kPa 和 0.46kPa。压缩使左心室和右心室的射血分数分别从 15.3%和 27.4%增加到 24.8%和 38.7%。在施加的压缩过程中，左心室游离壁的增厚增加，而右心室的变薄减少；这是由于游离壁的前负荷和后负荷的平衡发生了变化。主应变渲染显示左心室游离壁的前壁和后壁有应变集中。当施加 0.75 倍的归一化左心室力后，这些区域的应变呈指数增长。对这些应变进行分量分析表明，一旦超过 0.75 倍的归一化左心室力，主导应变从壁内纤维转移到交叉纤维。通过对每个压缩轮廓的每搏量和最大主应变进行无量纲化，创建了一个优化图，选择了五个潜在的压缩方案。这项工作不仅展示了直接心脏压缩的计算方法的重要性，还为根据患者的情况定制压缩方案提供了一个框架。
