Cardiologie clinique et expérimentale
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The End of Repeated Reoperations for Degenerated Bioprosthesis? Hydrodynamic In-Vitro Analysis for Sequential Valve-in-Valve Feasibility

Caio Cesar Cardoso*, Diego Felipe Gaia, José Honorio Palma, José de Lima Oliveira Jr

Objective: To develop a therapeutic guide for the implantation of Braile Inovare transcatheter valves within valvein-valve sets (including valve-in-valve-in-valve and sequential valve-in-valve configurations), based on hydrodynamic testing. The guide aims to establish therapeutic limits and recommend optimal sizes for transcatheter valves.

Materials and Methods: Hydrodynamic testing was performed using the pulse duplicator to measure the effective orifice area in square centimeter and the mean transvalvular gradient in millimetres of mercury of various valve sets. The tests adhered to Food and Drug Administration (FDA) and International Organization for Standardization (ISO) regulations, specifically ISO 5840. For sequential valve-in-valve testing, each selected valve-in-valve set was evaluated with a transcatheter valve smaller than the previously implanted valve. Each valve set was assembled in triplicate and each configuration underwent three pulse duplicator cycles in accordance with Food and Drug Administration (FDA) guidelines.

Results: The use of progressively smaller transcatheter valves in sequential implantation was informed by experiments that demonstrated stable prosthesis placement and reliable hemodynamic performance.

Sequential aortic valve-in-valve: Implantation of a 22 millimeters transcatheter valve inside a 25 millimeters bioprosthesis with a 24 millimeters transcatheter valve resulted in an effective orifice area of 0.99 square centimeter and a mean transvalvular gradient of 13.59 millimeters of mercury. Using a 20 mm transcatheter valve in the same set produced an effective orifice area of 0.84 square centimeter and a mean transvalvular gradient of 15.31 millimeters of mercury.

Sequential mitral valve-in-valve: Deployment of a 28 millimeters transcatheter valve inside a 31 millimeters bioprosthesis with a 30 millimeters transcatheter valve yielded an effective orifice area of 2.1 square centimeter and a mean transvalvular gradient of 3.6 millimeters of mercury. Sequential implantation of a 26 millimeters transcatheter valve in this set resulted in an effective orifice area of 1.99 square centimeter and a mean transvalvular gradient of 3.71 millimeters of mercury. Further implantation of a 24 millimeters transcatheter valve produced an effective orifice area of 1.67 square centimeter and a mean transvalvular gradient of 5.04 millimeters of mercury. Finally, deployment of a 22 millimeters transcatheter valve led to an effective orifice area of 1.07 square centimeter and a mean transvalvular gradient of 11.42 millimeters of mercury.

Conclusion: Sequential aortic valve-in-valve procedures are feasible and demonstrate satisfactory hydrodynamic performance with Braile Inovare transcatheter valves up to 22 millimeters in diameter. For sequential mitral valve-in-valve procedures, a cautious approach is recommended with 27 millimeters bioprostheses. The best hydrodynamic outcomes were observed with 29 millimeters and 31 millimeters bioprostheses, using a transcatheter valve size that is 1 millimeter smaller than the nominal size. Implantation of a 26 millimeters transcatheter valve in the sequential mitral valve-in- valve configuration is feasible with satisfactory performance, while the 24 millimeters transcatheter valve should be used with caution due to borderline transvalvular gradients and effective orifice area.