Computed Tomography Sizing Algorithm for Transcatheter Aortic Valve Implantation in Bicuspid Valve: Results From the CASPER Registry.

BACKGROUND

Bicuspid aortic valve (BAV) stenosis presents specific challenges for transcatheter aortic valve implantation (TAVI). Several transcatheter heart valve (THV) sizing strategies have been proposed. The CASPER algorithm (Calcium Algorithm Sizing for bicusPid aortic valve Evaluation with Raphe) indicates whether and how much to downsize the THV based on anatomic characteristics. The aim of this study was to prospectively assess the CASPER algorithm in a multicenter cohort of BAV patients treated with a self-expandable THV.

METHODS

Consecutive BAV patients undergoing TAVI were prospectively enrolled across 6 centers from 2022 to 2024. Preprocedural multislice computed tomography (MSCT) was used for THV sizing according to CASPER. Procedural features and clinical outcomes at 30 days and 1 year were recorded. Patients were compared based on whether CASPER recommended downsizing.

RESULTS

A total of 101 patients were included, and THV downsizing was advised in 39 cases (38.6%). The mean post-TAVI transvalvular gradient was 8.3 ± 4.3 mmHg, and moderate paravalvular leak occurred in 6 patients (6%). No deaths or major structural complications were reported, whereas the 30-day permanent pacemaker implantation rate was 25%. No significant differences between downsizing and non-downsizing groups were observed regarding procedural characteristics, hemodynamic performance, or clinical outcomes. Postprocedural MSCT (available in 84/101 patients, 83%) showed comparable THV eccentricity in both groups.

CONCLUSIONS

The CASPER algorithm offers a practical and reproducible sizing strategy for use in BAV anatomy and appears to support appropriate THV expansion while identifying cases requiring downsizing. However, in the absence of a comparator group, these findings should be considered hypothesis-generating and require validation in prospective comparative or randomized studies.

CLINICAL TRIAL REGISTRATION: NCT04817735.