Abstract：
OBJECTIVE: Patients presenting with coarctation of the aorta (CoA) may also suffer from co-existing transverse arch hypoplasia (TAH). Depending on the risks associated with the surgery and the severity of TAH, clinicians may decide to repair only CoA, and monitor the TAH to see if it improves as the patient grows. While acutely successful, eventually hemodynamics may become suboptimal if TAH is left untreated. The objective of this work aims to develop a patient-specific surgical planning framework for predicting and assessing postoperative outcomes of simple CoA repair and comprehensive repair of CoA and TAH.
METHODS: The surgical planning framework consisted of virtual clamp placement, stenosis resection, and design and optimization of patient-specific aortic grafts that involved geometrical modeling of the graft and computational fluid dynamics (CFD) simulation for evaluating various surgical plans. Time-dependent CFD simulations were performed using Windkessel boundary conditions at the outlets that were obtained from patient-specific non-invasive pressure and flow data to predict hemodynamics before and after the virtual repairs. We applied the proposed framework to investigate optimal repairs for six patients (n = 6) diagnosed with both CoA and TAH. Design optimization was performed by creating a combination of a tubular graft and a waterslide patch to reconstruct the aortic arch. The surfaces of the designed graft were parameterized to optimize the shape.
RESULTS: Peak systolic pressure drop (PSPD) and time-averaged wall shear stress (TAWSS) were used as performance metrics to evaluate surgical outcomes of various graft designs and implantation. The average PSPD improvements were 28% and 44% after the isolated CoA repair and comprehensive repair, respectively. Maximum values of TAWSS were decreased by 60% after CoA repair and further improved by 22% after the comprehensive repair. The oscillatory shear index was calculated and the values were confirmed to be in the normal range after the repairs.
CONCLUSIONS: The results showed that the comprehensive repair outperforms the simple CoA repair and may be more advantageous in the long term in some patients. We demonstrated that the surgical planning and patient-specific flow simulations could potentially affect the selection and outcomes of aorta repairs.
METHODS: The surgical planning framework consisted of virtual clamp placement, stenosis resection, and design and optimization of patient-specific aortic grafts that involved geometrical modeling of the graft and computational fluid dynamics (CFD) simulation for evaluating various surgical plans. Time-dependent CFD simulations were performed using Windkessel boundary conditions at the outlets that were obtained from patient-specific non-invasive pressure and flow data to predict hemodynamics before and after the virtual repairs. We applied the proposed framework to investigate optimal repairs for six patients (n = 6) diagnosed with both CoA and TAH. Design optimization was performed by creating a combination of a tubular graft and a waterslide patch to reconstruct the aortic arch. The surfaces of the designed graft were parameterized to optimize the shape.
RESULTS: Peak systolic pressure drop (PSPD) and time-averaged wall shear stress (TAWSS) were used as performance metrics to evaluate surgical outcomes of various graft designs and implantation. The average PSPD improvements were 28% and 44% after the isolated CoA repair and comprehensive repair, respectively. Maximum values of TAWSS were decreased by 60% after CoA repair and further improved by 22% after the comprehensive repair. The oscillatory shear index was calculated and the values were confirmed to be in the normal range after the repairs.
CONCLUSIONS: The results showed that the comprehensive repair outperforms the simple CoA repair and may be more advantageous in the long term in some patients. We demonstrated that the surgical planning and patient-specific flow simulations could potentially affect the selection and outcomes of aorta repairs.
摘要：
目的：出现主动脉缩窄（CoA）的患者也可能同时存在横弓发育不全（TAH）。根据与手术相关的风险和TAH的严重程度，临床医生可能会决定只修复CoA，并监测TAH，看看它是否随着患者的成长而改善。虽然非常成功，如果不治疗TAH,最终血液动力学可能变得次优.这项工作的目的是开发一个针对患者的手术计划框架，用于预测和评估简单CoA修复和CoA和TAH综合修复的术后结果。
方法：手术计划框架由虚拟夹钳放置组成，狭窄切除术,以及针对患者的主动脉移植物的设计和优化，涉及移植物的几何建模和计算流体动力学（CFD）模拟，以评估各种手术计划。使用从患者特定的无创压力和流量数据获得的出口处的Windkessel边界条件进行时间依赖性CFD模拟，以预测虚拟修复前后的血液动力学。我们应用拟议的框架来研究6例诊断为CoA和TAH的患者（n=6）的最佳修复。通过创建管状移植物和滑水补片的组合来重建主动脉弓，从而进行了设计优化。对设计的移植物的表面进行参数化以优化形状。
结果：使用收缩压峰值（PSPD）和时间平均壁切应力（TAWSS）作为性能指标，以评估各种移植物设计和植入的手术效果。隔离CoA修复和综合修复后，PSPD的平均改善分别为28%和44%，分别。CoA修复后TAWSS最大值下降60%,综合修复后进一步提高22%。计算振荡剪切指数，并在修复后确认值在正常范围内。
结论：结果表明，综合修复优于简单的CoA修复，并且在某些患者中从长远来看可能更有利。我们证明了手术计划和患者特定的流量模拟可能会影响主动脉修复的选择和结果。
方法：手术计划框架由虚拟夹钳放置组成，狭窄切除术,以及针对患者的主动脉移植物的设计和优化，涉及移植物的几何建模和计算流体动力学（CFD）模拟，以评估各种手术计划。使用从患者特定的无创压力和流量数据获得的出口处的Windkessel边界条件进行时间依赖性CFD模拟，以预测虚拟修复前后的血液动力学。我们应用拟议的框架来研究6例诊断为CoA和TAH的患者（n=6）的最佳修复。通过创建管状移植物和滑水补片的组合来重建主动脉弓，从而进行了设计优化。对设计的移植物的表面进行参数化以优化形状。
结果：使用收缩压峰值（PSPD）和时间平均壁切应力（TAWSS）作为性能指标，以评估各种移植物设计和植入的手术效果。隔离CoA修复和综合修复后，PSPD的平均改善分别为28%和44%，分别。CoA修复后TAWSS最大值下降60%,综合修复后进一步提高22%。计算振荡剪切指数，并在修复后确认值在正常范围内。
结论：结果表明，综合修复优于简单的CoA修复，并且在某些患者中从长远来看可能更有利。我们证明了手术计划和患者特定的流量模拟可能会影响主动脉修复的选择和结果。
