Subclinical Leaflet Thrombosis, Transcatheter Heart Valve Characteristics and Structural Valve Deterioration: Rationale and Design of the POPular PET TAVI Study.

BACKGROUND

Subclinical leaflet thrombosis is common after transcatheter aortic valve implantation (TAVI) and may contribute to structural valve deterioration over time, this may be influenced by transcatheter heart valve (THV) design and other valve-related factors.

METHODS

The 'Effect of Subclinical Leaflet Thrombosis and Prosthesis Type on Transcatheter Aortic Valve Degeneration (POPular PET TAVI)' study is an international, multicenter, cross-sectional cohort study. Patients (n=180) are enrolled at five years after TAVI for a detailed assessment of THV structure and function using a multi-modality imaging approach. High-resolution four-dimensional cardiac computed tomography (4D-CT) is used to assess subclinical leaflet thrombosis and THV characteristics (e.g. neosinus volume, prosthesis deformation index, valve expansion and commissural alignment). 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) is used to measure micro-calcification activity in the THV leaflets as a marker of structural valve deterioration. Transthoracic echocardiography is performed to evaluate THV and cardiac function. Obtained images are analyzed by dedicated Core Laboratories for PET and 4D-CT. To facilitate comparisons between balloon-expandable, intra-annular and self-expanding, supra-annular prostheses, enrollment is stratified for valve size and type. As of September 2026, 159 patients have been enrolled successfully, completion is anticipated in December 2026.

CONCLUSION

The POPular PET TAVI study evaluates the interplay between subclinical leaflet thrombosis, THV characteristics and structural valve deterioration at five years after TAVI. Improved understanding of these mechanisms may inform individualized antithrombotic strategies and optimized valve design aiming to enhance long-term valve durability.