Abstract：
OBJECTIVE: Transcatheter heart valves (THVs) are investigated according to International Organization for Standardization requirements using in vitro heart simulators to evaluate hydrodynamic performance. In contrast to surgical valves, a THV\'s performance heavily depends on the configuration and shape of the aortic anulus. In International Organization for Standardization regulations, there is no detailed definition for the construction of a compartment in which a THV has to be tested. Therefore, the aim of this in vitro study was to compare different in vitro models for functional testing of THVs.
METHODS: Porcine aortic conduits (23-mm diameter) were implanted in Dacron prostheses and calcified with double-distilled water and calcification buffer at 37°C over 83 million cycles in a Hi-Cycler (durability testing) mimicking nearly 3 patient-years. Hydrodynamic testing of Evolut PRO 26 mm was performed within 3 models (plexiglass, native conduit and calcified conduit; all 23-mm diameter) at a frequency of 64 bpm and different stroke volumes (55-105 ml).
RESULTS: Calcified conduits showed significantly higher mean pressure gradients (MPG) and lower effective orifice areas (EOA) in comparison to native conduits (without THV; P < 0.001). EOA and MPG of Evolut PRO differed depending on the model tested. Calcified conduits resulted in the lowest EOA and highest MPG of the THV compared to plexiglass and the native conduit. Full expansion of the THV was least impaired in the native conduit, while lowest geometric orifice area, lowest minimal internal diameter and highest pin-wheeling index of Evolut PRO were seen in the calcified conduit.
CONCLUSIONS: Full expansion and functional performance of the Evolut PRO THV depends on the configuration of the testing compartment in an in vitro setting.
METHODS: Porcine aortic conduits (23-mm diameter) were implanted in Dacron prostheses and calcified with double-distilled water and calcification buffer at 37°C over 83 million cycles in a Hi-Cycler (durability testing) mimicking nearly 3 patient-years. Hydrodynamic testing of Evolut PRO 26 mm was performed within 3 models (plexiglass, native conduit and calcified conduit; all 23-mm diameter) at a frequency of 64 bpm and different stroke volumes (55-105 ml).
RESULTS: Calcified conduits showed significantly higher mean pressure gradients (MPG) and lower effective orifice areas (EOA) in comparison to native conduits (without THV; P < 0.001). EOA and MPG of Evolut PRO differed depending on the model tested. Calcified conduits resulted in the lowest EOA and highest MPG of the THV compared to plexiglass and the native conduit. Full expansion of the THV was least impaired in the native conduit, while lowest geometric orifice area, lowest minimal internal diameter and highest pin-wheeling index of Evolut PRO were seen in the calcified conduit.
CONCLUSIONS: Full expansion and functional performance of the Evolut PRO THV depends on the configuration of the testing compartment in an in vitro setting.
摘要：
目的：根据国际标准化组织（ISO）的要求，使用体外心脏模拟器研究经导管心脏瓣膜（THV）以评估流体动力学性能。与外科瓣膜相反，THV的性能在很大程度上取决于主动脉瓣环的结构和形状。在ISO法规中，对于必须测试THV的隔室的构造没有详细定义。因此,这项体外研究的目的是比较THV功能测试的不同体外模型.
方法：将猪主动脉导管（直径23mm）植入Dacron假体中，并用双蒸水和钙化缓冲液在37°C下进行了8300万个循环，模拟了近3个患者年的Hi-Cycler（耐久性测试）。在3个型号内进行了EvolutPRO26mm的水动力测试(有机玻璃，天然导管和钙化导管；所有直径为23mm），频率为64bpm和不同的冲程量（55ml-105ml）。
结果：与天然导管（无THV；p<0.001）相比，钙化导管显示出明显更高的平均压力梯度（MPG）和更低的有效孔口面积（EOA）。EvolutPRO的EOA和MPG根据所测试的模型而有所不同。与有机玻璃和天然导管相比，钙化导管导致THV的EOA最低和MPG最高。在天然导管中，THV的完全扩张受到的损害最小，而最低的几何孔口面积，在钙化导管中观察到EvolutPRO的最低最小内径和最高针轮指数。
结论：EvolutPRO经导管心脏瓣膜的完全扩张和功能性能取决于体外环境中测试室的配置。
方法：将猪主动脉导管（直径23mm）植入Dacron假体中，并用双蒸水和钙化缓冲液在37°C下进行了8300万个循环，模拟了近3个患者年的Hi-Cycler（耐久性测试）。在3个型号内进行了EvolutPRO26mm的水动力测试(有机玻璃，天然导管和钙化导管；所有直径为23mm），频率为64bpm和不同的冲程量（55ml-105ml）。
结果：与天然导管（无THV；p<0.001）相比，钙化导管显示出明显更高的平均压力梯度（MPG）和更低的有效孔口面积（EOA）。EvolutPRO的EOA和MPG根据所测试的模型而有所不同。与有机玻璃和天然导管相比，钙化导管导致THV的EOA最低和MPG最高。在天然导管中，THV的完全扩张受到的损害最小，而最低的几何孔口面积，在钙化导管中观察到EvolutPRO的最低最小内径和最高针轮指数。
结论：EvolutPRO经导管心脏瓣膜的完全扩张和功能性能取决于体外环境中测试室的配置。
