Prosthesis-Patient Mismatch after Aortic Valve Replacement with the Mosaic Ultra Bioprosthesis.

Background:  Several studies have reported high rates of prosthesis-patient mismatch (PPM) after aortic valve replacement (AVR) with the Mosaic prosthesis. This work assesses the incidence of PPM after AVR with a modified version of the Mosaic prosthesis, the Mosaic Ultra.

Methods:  We performed a retrospective analysis of the data of 532 patients who underwent AVR with implantation of the Mosaic Ultra prosthesis in the period 2007-2016 in our institution. Patients were classified according to their indexed effective orifice area (EOAi) to severe (EOAi < 0.65 cm²/m²), moderate (EOAi 0.65-0.85 cm²/m²), and absent/mild PPM (EOAi > 0.85 cm²/m²). In-hospital postoperative outcomes and the impact of PPM on mean transvalvular pressure gradient after stratification by prosthesis size were assessed.

Results:  Overall, 3 (0.6%) patients had severe, 92 (17.3%) moderate, and 437 (82.1%) absent/mild PPM. There was a significant difference in PPM proportions (moderate/severe vs absent/mild PPM) across different prosthesis sizes overall (p < 0.0001), observing gradually increasing rates of PPM with decreasing prosthesis sizes. Patients with moderate/severe PPM had higher mean transvalvular pressure gradients (19 [13-25] vs 13 [10-17] mm Hg, p < 0.0001) than patients with absent/mild PPM. There was a significant difference in mean transvalvular pressure gradient between the different aortic valve prosthesis sizes overall (p < 0.0001), observing gradually increasing gradients with decreasing prosthesis sizes.

Conclusion:  Patients undergoing AVR with the smaller sized (19, 21, and 23 mm) Mosaic Ultra aortic valve prostheses exhibit a higher risk for moderate/severe PPM and higher mean aortic transvalvular pressure gradients than patients receiving the larger sized (25, 27, and 29 mm) prostheses.