Table 3

Putative Underlying Mechanisms for Subclinical Leaflet Thrombosis: Virchow’s Triad

StasisVessel Wall: Endothelial InjuryRheology: Hypercoagulability
Low flow states (e.g., low EF, LFLG/PLFLG AS)Leaflet injury (during chemical leaflet fixation, TAVR loading/crimping, balloon dilation or post-dilatation)Pro-thrombotic states
Device depth: more ventricular placement contributing to nonlaminar flowImmune activation with leaflet “rejection”Frame distortion or “strut bunching” causing leaflet asymmetry, folding and pro-coagulable pockets

AS = aortic stenosis; EF = ejection fraction; LFLG = low-flow low-gradient; PLFLG = paradoxical low-flow low gradient; TAVR = transcatheter aortic valve replacement.