A Novel computational approach to optimize Fontan and improve surgical predictability

手术后有效的血流动力学和最小的血栓形成风险对于短期和长期是必不可少的。 心脏手术的成功。实现这一点在心脏手术中是一个挑战，它涉及到设计一种 复杂的流动路径。主动脉弓重建、动脉瘤修复、Fontan手术就是几个例子。 Fontan手术是单心室患者最有效的姑息治疗方法 缺陷(SVD)。Svd指的是先天性心脏病的集合，其中一个是下脑室 心腔仍然不发达。Fontan手术涉及重新安排脱氧血液的路线 从上半身和下半身直接流到肺，允许单个功能的脑室泵血 体循环。通过挽救生命，Fontan生理学为静脉回流创造了一条非自然的途径 血液流入肺部，从而产生非生理的血液流动。成功的Fontan手术应该是 涉及1)平衡的整体和肝静脉流回肺，以防止肺动静脉 可导致气体交换不良的畸形(PAVM)，2)能量损失最小，3)最小血栓形成 (血液凝块)风险。并发症，如肺静脉畸形和术后血栓形成，可导致Fontan衰竭。 为了改进方坦手术计划，其有效性和可预测性，我们建议开发一种自动化的 基于图像的计算流体力学(CFD)工作流能够优化和预测以上所有内容 方坦生理学成功的决定因素。过去已经开发了CFD模型来评估能源 损失和肝静脉血流分布，但一个自动计算工具，快速优化患者的 方坦生理学方面不存在影响成功的因素。为了填补这一空白，我们将整合我们的 预测能量损失和肝静脉血流的现有患者特有的Fontan手术计划方案 分布包括1)形状优化算法和2)我们验证的血液凝固模型，以提供 实质上改善计划中的Fontan生理学以优化肝脏和整体静脉的计算工具 恢复到肺，最小的能量损失和血栓形成潜力，并定量预测血栓形成的风险。我们会 使用自定义脚本完全自动化我们的工作流程，以最大限度地减少错误和用户干预。我们的生物化学 凝血模型具有代表血小板和纤维蛋白沉积的所有成分，并且是双向的 再加上血液流动。该模型基于连续体的方法使其可以用于大型几何图形。 在使用基于MRI的患者特定体外模型对我们的手术优化工作流程进行严格验证后， 我们将使用我们的工具和回顾患者数据进行虚拟手术，以建立临床适用性。 我们的工具可能1)包括在当前的手术计划工作流程中，以执行虚拟手术 使用患者术前数据来改善和预测手术结果，以及2)用于评估术后凝血的风险。 方坦使患者可以有选择地进行监测。我们的长期目标是提供一种预期的外科手术 Fontan的计划工具，然后将其扩展到其他手术，在这些优化可以提高手术疗效的地方。

An efficient hemodynamics with minimal thrombosis risk post-surgery is essential for short- and long-term success of a cardiac surgery. Achieving this is a challenge in cardiac surgery that involves the design of a complex flow pathway. Aortic arch reconstruction, aneurysm repair, Fontan surgeries are a few examples. The Fontan surgical procedure is the most effective palliative treatment for patients with single ventricle defects (SVD). SVD refers to a collection of congenital heart diseases where one of the lower ventricular chambers of the heart remains underdeveloped. Fontan procedure involves re-routing of deoxygenated blood from upper and lower body to flow directly to lungs allowing the single functioning ventricle to pump blood for systemic circulation. Though lifesaving, the Fontan physiology creates a non-natural pathway for venous return of the blood to the lungs thus producing a non-physiological blood flow. A successful Fontan procedure should involve 1) well-balanced overall and hepatic venous flow return to lungs to prevent pulmonary arteriovenous malformations (PAVMs) that can lead to poor gas exchange, 2) minimal energy loss, and 3) minimal thrombosis (blood clot) risk. Complications such as PAVMs and thrombosis post-surgery can result in a Fontan failure. To improve Fontan surgical planning, its efficacy and predictability, we propose to develop an automated image-based computational fluid dynamics (CFD) workflow capable of optimizing and predicting all the above determinants for a successful Fontan physiology. CFD models have been developed in the past to assess energy loss and hepatic venous flow distribution, but an automated computational tool for rapidly optimizing the patients' Fontan physiology in terms of factors affecting success does not exist. To fill this gap, we will integrate our existing patient-specific Fontan surgical planning protocol to predict energy loss and hepatic venous flow distribution with 1) a shape optimization algorithm and 2) our validated model of blood coagulation to provide a computational tool to virtually improve the planned Fontan physiology for optimal hepatic and overall venous return to lungs, minimal energy loss and thrombotic potential and quantitatively predict thrombosis risk. We will completely automate our workflow with custom scripts to minimize errors and user intervention. Our biochemical model of blood coagulation has all the components representing platelet and fibrin deposition and is 2-way coupled with blood flow. The continuum-based approach of this model allows it to be used in large geometries. After rigorous validation of our surgical optimization workflow using MRI-based patient specific in-vitro models, we will perform virtual surgeries using our tool and retrospective patient data to establish clinical applicability. Our tool could potentially be 1) included in the current surgical planning workflow to perform virtual surgeries using patient pre-op data to improve and predict surgical outcomes, and 2) used to evaluate risk of clotting post- Fontan so that patients can be selectively monitored. Our long-term objective is to provide a prospective surgical planning tool for Fontan and then extend it other surgeries where such optimization can improve surgical efficacy.