Abstract：
BACKGROUND: The etiology of transcatheter aortic valve (TAV) degeneration is poorly understood, particularly noncalcific mechanisms.
OBJECTIVE: The authors sought to investigate noncalcific and calcific mechanisms of TAV degeneration and evaluate their impact on leaflet function by bench testing, imaging, and histology.
METHODS: TAV explants were obtained from the EXPLANT THV registry and clinical institutions. Hydrodynamic assessment was performed using a heart valve pulse duplicator system under physiological conditions. Micro-computed tomography, high-resolution photography, high speed video, and hematoxylin and eosin staining were used to evaluate the morphological appearance, leaflet kinematics, and calcium burden of TAVs.
RESULTS: A total of 14 explants were evaluated: 10 self-expanding CoreValve/Evolut TAVs (Medtronic), 3 balloon-expandable SAPIEN 3 TAVs (Edwards Lifesciences), and 1 mechanically expandable Lotus TAV (Boston Scientific). The median patient age at explantation was 73.0 years (Q1-Q3: 64.5-80.0 years), with a time to explantation of 4 years 1 month (1 year 5 months to 4 years 11 months). Six TAV explants were found to have leaflet calcification (162.4 mm3; 58.8-603.0 mm3), and 8 had no calcification detectable by micro-computed tomography and histology. All samples had impaired leaflet kinematics. There was no significant difference in the hydrodynamic mean gradient between calcified (47.2 mm Hg; 26.6-74.1 mm Hg) and noncalcified (27.6 mm Hg; 15.2-36.7 mm Hg; P = 0.28) TAVs. Leaflet calcification had a weak but nonsignificant association with the hydrodynamic mean gradient (r = 0.42; P = 0.14).
CONCLUSIONS: TAV function can be severely impacted by noncalcific and calcific mechanisms of tissue degeneration. Importantly, functional stenosis can occur in TAVs in the absence of obvious and significant calcification.
OBJECTIVE: The authors sought to investigate noncalcific and calcific mechanisms of TAV degeneration and evaluate their impact on leaflet function by bench testing, imaging, and histology.
METHODS: TAV explants were obtained from the EXPLANT THV registry and clinical institutions. Hydrodynamic assessment was performed using a heart valve pulse duplicator system under physiological conditions. Micro-computed tomography, high-resolution photography, high speed video, and hematoxylin and eosin staining were used to evaluate the morphological appearance, leaflet kinematics, and calcium burden of TAVs.
RESULTS: A total of 14 explants were evaluated: 10 self-expanding CoreValve/Evolut TAVs (Medtronic), 3 balloon-expandable SAPIEN 3 TAVs (Edwards Lifesciences), and 1 mechanically expandable Lotus TAV (Boston Scientific). The median patient age at explantation was 73.0 years (Q1-Q3: 64.5-80.0 years), with a time to explantation of 4 years 1 month (1 year 5 months to 4 years 11 months). Six TAV explants were found to have leaflet calcification (162.4 mm3; 58.8-603.0 mm3), and 8 had no calcification detectable by micro-computed tomography and histology. All samples had impaired leaflet kinematics. There was no significant difference in the hydrodynamic mean gradient between calcified (47.2 mm Hg; 26.6-74.1 mm Hg) and noncalcified (27.6 mm Hg; 15.2-36.7 mm Hg; P = 0.28) TAVs. Leaflet calcification had a weak but nonsignificant association with the hydrodynamic mean gradient (r = 0.42; P = 0.14).
CONCLUSIONS: TAV function can be severely impacted by noncalcific and calcific mechanisms of tissue degeneration. Importantly, functional stenosis can occur in TAVs in the absence of obvious and significant calcification.
摘要：
背景：经导管主动脉瓣（TAV）变性的病因知之甚少，尤其是非钙化机制。
目的：作者试图研究TAV变性的非钙化和钙化机制，并通过台架试验评估其对小叶功能的影响，成像,和组织学。
方法：TAV外植体从EXPLANTTHV注册中心和临床机构获得。在生理条件下使用心脏瓣膜脉冲复制器系统进行流体动力学评估。微型计算机断层扫描,高分辨率摄影，高速视频,苏木精和伊红染色用于评估形态学外观，小叶运动学，和TAV的钙负担。
结果：总共评估了14个外植体：10个自膨胀CoreValve/EvolutTAV（Medtronic），3个气球可扩展的SAPIEN3TAV（爱德华兹生命科学），和1可机械扩展的莲花TAV（波士顿科学）。植入时的中位患者年龄为73.0岁（Q1-Q3：64.5-80.0岁），与时间4年1个月（1年5个月至4年11个月）的外植体。发现六个TAV外植体具有小叶钙化（162.4mm3;58.8-603.0mm3），8例未通过显微计算机断层扫描和组织学检测到钙化。所有样本的小叶运动学均受损。钙化（47.2mmHg；26.6-74.1mmHg）和非钙化（27.6mmHg；15.2-36.7mmHg；P=0.28）TAV之间的流体动力学平均梯度无显着差异。小叶钙化与流体动力学平均梯度的相关性较弱，但不显着（r=0.42；P=0.14）。
结论：组织变性的非钙化和钙化机制可严重影响TAV功能。重要的是,在没有明显和显著钙化的情况下，TAVs可发生功能性狭窄。
目的：作者试图研究TAV变性的非钙化和钙化机制，并通过台架试验评估其对小叶功能的影响，成像,和组织学。
方法：TAV外植体从EXPLANTTHV注册中心和临床机构获得。在生理条件下使用心脏瓣膜脉冲复制器系统进行流体动力学评估。微型计算机断层扫描,高分辨率摄影，高速视频,苏木精和伊红染色用于评估形态学外观，小叶运动学，和TAV的钙负担。
结果：总共评估了14个外植体：10个自膨胀CoreValve/EvolutTAV（Medtronic），3个气球可扩展的SAPIEN3TAV（爱德华兹生命科学），和1可机械扩展的莲花TAV（波士顿科学）。植入时的中位患者年龄为73.0岁（Q1-Q3：64.5-80.0岁），与时间4年1个月（1年5个月至4年11个月）的外植体。发现六个TAV外植体具有小叶钙化（162.4mm3;58.8-603.0mm3），8例未通过显微计算机断层扫描和组织学检测到钙化。所有样本的小叶运动学均受损。钙化（47.2mmHg；26.6-74.1mmHg）和非钙化（27.6mmHg；15.2-36.7mmHg；P=0.28）TAV之间的流体动力学平均梯度无显着差异。小叶钙化与流体动力学平均梯度的相关性较弱，但不显着（r=0.42；P=0.14）。
结论：组织变性的非钙化和钙化机制可严重影响TAV功能。重要的是,在没有明显和显著钙化的情况下，TAVs可发生功能性狭窄。
