Bicuspid aortic valve sizing for transcatheter aortic valve implantation: Development and validation of an algorithm...

No indication are available for transcatheter aortic valve implantation (TAVI) sizing in bicuspid aortic valve (BAV). Aim of the study is to develop and validate a Multi-Slice Computed Tomography (MSCT)-based algorithm for transcatheter heart valve (THV) sizing in patients with stenotic BAV under evaluation for TAVI.

A two steps method was applied: 1)evaluation of a cohort of 19 consecutive patients with type I BAV stenosis undergoing TAVI through pre and post-procedural MSCT, and development of an algorithm for THV sizing; 2)validation of the algorithm on a new cohort of 21 patients.

In the first cohort, a high correlation was found between the raphe-level area measured at pre-procedural MSCT and the smallest THV area measured at post-procedural MSCT (p < 0.001). Moreover, reduced THV expansion was observed among patients with higher calcium burden (p = 0.048). Then, a new algorithm for TAVI sizing in BAV was develop (CASPER: Calcium Algorithm Sizing for bicusPid Evaluation with Raphe). This algorithm is based on the reassessment of the perimeter/area derived annulus diameter, according to three main anatomical features: 1) the ratio between raphe length and annulus diameter; 2)calcium burden; 3)calcium distribution in relation to the raphe. The algorithm was then validated in a new cohort of 21 patients, achieving 100% of procedural success and excellent TAVI performance.

MSCT assessment of raphe length, calcium burden and its distribution is of crucial relevance in the pre-procedural evaluation of patients with BAV. These anatomical features can be combined in a new and simple algorithm for TAVI sizing.