%0 Journal Article
%T Hydrodynamic Assessment of Explanted Degenerated Transcatheter Aortic Valves: Novel Insights Into Noncalcific and Calcific Mechanisms.
%A Sathananthan J
%A Nigade A
%A Meier D
%A Navarro D
%A Spencer J
%A Lai A
%A Gill H
%A Pirelli L
%A Webb JG
%A Wood DA
%A Lutter G
%A Puehler T
%A Tang GHL
%A Fukuhara S
%A Sellers SL
%J JACC Cardiovasc Interv
%V 17
%N 11
%D 2024 Jun 10
%M 38866457
%F 11.075
%R 10.1016/j.jcin.2024.04.011
%X <B>BACKGROUND: </B>The etiology of transcatheter aortic valve (TAV) degeneration is poorly understood, particularly noncalcific mechanisms.<BR><B>OBJECTIVE: </B>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.<BR><B>METHODS: </B>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.<BR><B>RESULTS: </B>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).<BR><B>CONCLUSIONS: </B>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.