Undersizing but overfilling eliminates the gray zones of sizing for transcatheter aortic valve replacement with the balloon-expandable bioprosthesis

Background: Current recommendations for valve size selection are based on multidimensional annular measurements, yet the overlap between two different transcatheter heart valve (THV) sizes remains. We sought to evaluate whether undersizing but overfilling eliminates the gray zones of valve sizing. Methods: Data of 246 consecutive patients undergoing transcatheter aortic valve replacement (TAVR) with the balloon-expandable bioprosthesis with either conventional sizing and nominal filling (group 1 (NF-TAVR), n = 154) or undersizing but overfilling under a Less Is More (LIM)-Principle (group 2 (LIM-TAVR), n = 92) were compared. Paravalvular leakage (PVL) was graded angiographically and quantitatively using invasive hemodynamics. Results: Annulus rupture (AR) occurred only in group 1 (n = 3). Due to AR adequate evaluation of PVL was possible in 152 patients of group 1. More than mild PVL was found in 13 (8.6%) patients of group 1 and 1 (1.1%) patient of group 2 (p = 0.019). Postdilatation was performed in 31 (20.1%) patients of group 1 and 6 patients (6.5%) of group 2 (p = 0.003). For patients with borderline annulus size in group 1 (n = 35, 22.7%) valve size selection was left to the physiciańs choice resulting in selection of the larger prosthesis in 10 (28.6%). In group 2 all patients with borderline annulus (n = 36, 39.1%) received the smaller prosthesis (LIM-TAVR). The postprocedural mean transvalvular pressure gradient was significantly higher in the NF-TAVR-group (11.7 ± 4 vs. 10.1 ± 3.6 mmHg, p = 0.005). Conclusion: LIM-TAVR eliminates the gray zones of sizing and associated PVL, can improve THV-performance, reduce incidence of annular rupture and simplify the procedure especially in borderline cases.