Hemodynamic and clinical performance of the 25-mm Medtronic Mosaic porcine bioprosthesis in the mitral position

The 25-mm Medtronic Mosaic porcine bioprosthesis (MB25) is the smallest bioprosthesis that has been approved for use in the mitral position in Japan. Various studies have reported satisfactory hemodynamic performance and good long-term outcomes of the Medtronic Mosaic porcine bioprosthesis. However, the hemodynamic and clinical performances of the MB25 in the mitral position remain unknown. This study aimed to evaluate the hemodynamic and clinical performance of the MB25 in mitral valve replacement (MVR). Twenty patients who underwent MVR using the MB25 between February 2013 and April 2018 were studied. We evaluated the hemodynamic performance of the MB25, cardiac chamber size, cardiac function, and systolic pulmonary artery pressure (PAP) using echocardiography during follow-up. The study outcomes were major adverse cardiac events (MACEs) and all-cause mortality. Sixteen patients (80%) had a patient prosthesis mismatch defined as an index effective orifice area of ≤ 1.2 cm 2 /m 2 . The left atrial dimension was significantly reduced after surgery ( p = 0.0282). The mean pressure gradients (MPG) in the mitral position were 5.5 ± 1.7 mmHg at discharge and 4.2 ± 1.3 mmHg at 1 year postoperatively. The MPG in the mitral position significantly decreased during the follow-up period ( p = 0.0489). Systolic PAP significantly improved postoperatively. The 1-, 3-, and 5-year survival rates were 87, 79, and 70%, respectively. No cardiac death occurred. There were no MACEs or reports of structural valve degeneration during the follow-up period. The hemodynamic and clinical performances of the MB25 in the mitral position were satisfactory as the smallest biological mitral valve. The MB25 is a reasonable option for MVR to reduce the surgical difficulty in high-risk patients with an advanced age, a small body size or MAC and when recurrent MVR or complex procedures are performed.