Ross手术后即刻肺动脉自体移植物对体循环压力的反应范围
Range of Pulmonary Autograft Responses to Systemic Pressure Immediately After Ross Procedure.
作者信息
Wisneski Andrew D, Wang Zhongjie, Xuan Yue, Guccione Julius M, Ge Liang, Tseng Elaine E
机构信息
Department of Surgery, University of California San Francisco (UCSF) and San Francisco Veterans Affairs Medical Center (SFVAMC), San Francisco, CA, USA.
出版信息
J Heart Valve Dis. 2019;28(1):22-31.
BACKGROUND
Pulmonary autograft dilatation after Ross operation often necessitates reoperation. To understand autograft remodeling, a biomechanical understanding of human autografts after exposure to systemic pressure is required. We previously developed an human pulmonary autograft finite element (FE) model to predict wall stress after exposure to systemic pressure. However, autograft material properties vary significantly among individuals. Our study aim was to quantify range of wall stress changes in a human autograft after Ross operation prior to remodeling based upon normal variation in human autograft mechanical properties.
METHODS
A normal human autograft FE model was loaded to pulmonary and systemic arterial pressures. Stress-strain data of normal human autografts (n=24) were incorporated into an Ogden hyper-elastic model to describe autograft mechanical behavior. Autograft wall stresses at pulmonary vs. systemic pressures were examined. Autograft volume-based stress analysis was performed, based on percentage of autograft element volume exceeding 1 standard deviation (SD) above group mean stress at systemic systole.
RESULTS
Mean first principal wall stresses (FPS) at systole of systemic versus pulmonary pressures were 129.29±17.47kPa versus 24.42±3.85kPa (p<0.001) at the annulus, 187.53±20.06kPa versus 35.98±2.15kPa at sinuses (p<0.001), and 268.68±23.40kPa versus 50.15±5.90kPa (p<0.001) at sinotubuluar junction (STJ). The percentage of autograft element volume that exceeded one SD above the group mean was 14.3±5.6% for FPS and 12.6±10.1% for second principal stresses.
CONCLUSION
We quantified normal human autograft biomechanical responses to systemic pressure based on patient-specific material properties. Regions of peak stresses were observed in autograft sinuses and STJ regions, which corresponded clinically to locations of autograft dilation. Our results provide valuable information on predicting variations in patient-specific FE models when population-based material properties are used in settings where patient-specific properties are unknown.
背景
Ross手术后肺动脉自体移植物扩张常常需要再次手术。为了解自体移植物重塑，需要对暴露于体循环压力后的人体自体移植物进行生物力学理解。我们之前开发了一个人体肺动脉自体移植物有限元（FE）模型，以预测暴露于体循环压力后的壁应力。然而，自体移植物的材料特性在个体间差异显著。我们的研究目的是基于人体自体移植物力学特性的正常变异，量化Ross手术后人体自体移植物在重塑前壁应力变化的范围。
方法
将一个正常人体自体移植物FE模型加载到肺动脉和体循环动脉压力。将正常人体自体移植物（n = 24）的应力-应变数据纳入Ogden超弹性模型，以描述自体移植物的力学行为。检查肺动脉与体循环压力下的自体移植物壁应力。基于自体移植物单元体积超过体循环收缩期组平均应力1个标准差（SD）以上的百分比，进行自体移植物基于体积的应力分析。
结果
在瓣环处，体循环压力与肺动脉压力收缩期的平均第一主壁应力（FPS）分别为129.29±17.47kPa和24.42±3.85kPa（p<0.001）；在窦部，分别为187.53±20.06kPa和35.98±2.15kPa（p<0.001）；在窦管交界（STJ）处，分别为268.68±23.40kPa和50.15±5.90kPa（p<0.001）。FPS超过组平均1个SD以上的自体移植物单元体积百分比为14.3±5.6%，第二主应力为12.6±10.1%。
结论
我们基于患者特异性材料特性量化了正常人体自体移植物对体循环压力的生物力学反应。在自体移植物窦部和STJ区域观察到应力峰值区域，这在临床上与自体移植物扩张的位置相对应。我们的结果为在未知患者特异性特性的情况下使用基于群体的材料特性来预测患者特异性FE模型的变化提供了有价值的信息。
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