Towards Patient-specific Simulations and Treatment Methods in Cardiology: Develop-ment of a Comprehensive Numerical Framework for Left Ventricle Remodelling

据世界卫生组织统计，2015年，全球平均每两秒钟就有一人死于心血管疾病，占全球死亡总人数的31%。在过去的几十年里，临床医生和工程师之间的跨学科研究取得了重大进展，他们处理数值建模，以了解心脏的工作机制，降低心血管疾病的死亡率和经济后果。特别是左心室（LV）重构是心内科常见的病理病例。存在独特的性质和条件的每个病人复杂，以确定疾病的严重程度和其最佳的治疗策略。此外，目前的心脏分析方法有局限性，需要更深入地了解左室重构。在这种情况下，计算方法可能提供一种有前途的虚拟调查能力，即非侵入性，相对便宜和快速，并帮助心脏病专家为特定患者选择最合适的治疗方法。受这个想法的启发，结构分析研究所和德累斯顿工业大学心脏病学系将进行跨学科的研究合作，结合医学和工程能力，目的是提供先进的精确的左室重构计算机分析，特别是在病理条件下。在这方面，将设立几个新项目。其中一个重要的创新发展将是基于有限元（FE）的方法，该方法将从工程角度分析从心脏磁共振成像和3D超声心动图获得的临床数据，提供值的点向分布，不像医学评估软件中的平均段值，以及左室的几何形状分析。这种创新的方法将有助于在临床常规中定义更强大的标志物来识别疾病的严重程度和预测疾病的进展。此外，通过这种方法分析临床数据将指导我们为左室重塑制定广泛的本构律。与文献中现有的LV重塑材料模型不同，几个重要的特征将统一在一个流变学中。为此，重构方面，如体积生长、纤维化合成和纤维取向变化将嵌入到改进的Hill模型中，该模型被提出用于描述心肌的电粘活性反应。该研究计划的另一个重要特征将是实现基于有限元的流体-结构相互作用算法，以模拟左室内血液的存在，这将最终提高计算机模拟的真实感。最后，我们的目标是对通用和个性化LV几何形状进行全面的有限元分析，以验证开发的数值框架。

According to the statistics of the World Health Organization, in 2015, an average of one death every 2 seconds came into existence due to cardiovascular diseases (CVDs), which was 31% of all global deaths. Over the last decades, a significant progress has been achieved in interdisciplinary research between clinicians and engineers, who deal with numerical modelling, to understand the working mechanisms of the heart and reduce mortality and economic consequences of CVDs.In particular, left ventricle (LV) remodelling is a frequently encountered pathological case in cardiology departments. The existence of unique properties and conditions of each patient complicates to identify the disease severity and its optimum treatment strategy. Besides, current cardiac analysing methods have limitations and a deeper insight into LV remodelling is needful. In this context, computational approaches might provide a promising investigation capability that is virtual, i.e. non-invasive, relatively cheap and fast, and assist cardiologists to choose the most appropriate treatment method for a specific patient. Inspired by this idea, the Institute for Structural Analysis and the Department of Cardiology, TU Dresden, will perform an interdisciplinary research cooperation that combines medical and engineering competences with the objective to provide advanced precise computer analysis of LV remodelling particularly under pathological conditions. In this regard, several novelties will be established. One of the significant innovative developments will be a finite element (FE) based methodology that will analyse clinical data obtained from cardiac magnetic resonance imaging and 3D echocardiography with an engineering perspective providing a pointwise distribution of values, unlike averaged segment values as in medical assessment softwares, and geometrical shape analysis of the LV. Such an innovative approach would facilitate to define more robust markers identifying the disease severity and prognosticate disease progression in clinical routine. Furthermore, analysis of the clinical data through this methodology will guide us to develop an extensive constitutive law for LV remodelling. Unlike existing material models for LV remodelling in the literature, several important characteristics will be unified in one rheology. For this purpose, the remodelling aspects such as volumetric growth, fibrosis synthesis and fibre orientation change will be embedded into the modified Hill model, which was proposed to describe the electro-visco-active response of the myocardium. Another essential feature of the research program will be the implementation of an FE based fluid-structure interaction algorithm in order to mimic the presence of blood within the LV, which will eventually improve the realism of computer simulations. Finally, we aim to perform comprehensive FE analyses of generic and personalized LV geometries in order to validate the developed numerical framework.