: The frequent occurrence of thromboembolic cerebral events continues to limit the widespread implementation of Ventricular Assist Devices (VAD) despite continued advancements in VAD design and anti-coagulation treatments. Recent studies point to the optimal positioning of the outflow graft (OG) as a potential mitigator of post implantation thromboembolism. : This study aims to examine the tailoring of the OG implantation orientation with the goal of minimizing the number of thrombi reaching the cerebral vessels by means of a formal shape optimization scheme incorporated into a multi-scale hemodynamics analysis. : A 3-D patient-specific computational fluid dynamics model is loosely coupled in a two-way manner to a 0-D lumped parameter model of the peripheral circulation. A Lagrangian particle-tracking scheme models and tracks thrombi as non-interacting solid spheres. The loose coupling between CFD and LPM is integrated into a geometric shape optimization scheme which aims to optimize an objective function that targets a drop in cerebral embolization, and an overall reduction in particle residence times. : The results elucidate the importance of OG anastomosis orientation and placement particularly in the case that studied particle release from the OG, as a fivefold decrease in cerebral embolization was observed between the optimal and non-optimal implantations. Another case considered particle release from the ventricle and aortic root walls, in which optimal implantation was achieved with a shallow insertion angle. Particle release from all three origins was investigated in the third case, demonstrating that the optimal configurations were generally characterized by VAD flow directed along the central lumen of the aortic arch. Because optimal configurations depended on the anatomic origin of the thrombus, it is important to determine, in clinical studies, the most likely sites of thrombus formation in VAD patients.

中文翻译：

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使用耦合多尺度多目标优化定制左心室辅助装置插管植入

：尽管 VAD 设计和抗凝治疗不断取得进步，但血栓栓塞性脑事件的频繁发生仍然限制了心室辅助装置 (VAD) 的广泛实施。最近的研究指出，流出移植物（OG）的最佳定位是植入后血栓栓塞的潜在缓解剂。：本研究旨在检查 OG 植入方向的定制，目的是通过纳入多尺度血流动力学分析的正式形状优化方案，最大限度地减少到达脑血管的血栓数量。：3-D 患者特定计算流体动力学模型以双向方式松散耦合到外周循环的 0-D 集总参数模型。拉格朗日粒子跟踪方案将血栓建模并跟踪为非相互作用的实心球体。CFD 和 LPM 之间的松散耦合被集成到几何形状优化方案中，该方案旨在优化目标函数，以减少脑栓塞并总体减少颗粒停留时间。：结果阐明了 OG 吻合方向和放置的重要性，特别是在研究 OG 颗粒释放的情况下，因为在最佳和非最佳植入之间观察到脑栓塞减少了五倍。另一个案例考虑了从心室和主动脉根壁释放颗粒，其中通过浅插入角度实现了最佳植入。在第三个案例中对所有三个来源的颗粒释放进行了研究，表明最佳配置的特征通常是沿着主动脉弓中央腔引导的 VAD 流。由于最佳配置取决于血栓的解剖起源，因此在临床研究中确定 VAD 患者最可能形成血栓的部位非常重要。