Comprehensive and Integrative Experimentation Setup for Large Animal Hybrid Valvular Heart Surgery

Experimental surgical procedures for atrioventricular valves present promising translational capabilities, and preclinical studies are necessary to assess their applicability and to train young enthusiastic heart teams. Here, we present a synopsis of experimental surgical procedures on porcine models for mitral valvular (MV) and tricuspid valvular (TV) interventions; mitral valve-in-valve implantation (MViV), transapical cardioscopic (TAC) MV replacement (MVR), TAC-MV annuloplasty, and tricuspid valve-in-a-ring (TViR) procedures.

Twenty-five (n = 25) female Yorkshire pigs of 55-65 kg is the total number used in the four approaches; seven animals underwent MViV, six TAC-MVR, six TAC-MV annuloplasty, and six TViR, respectively. All were subjected to a first conventional valvular surgery (bioprosthetic valve replacement and/or prosthetic ring repair). Then, after 4 wk, a less-invasive second surgery was performed using the transcatheter approaches under investigation. Except for the TAC-MVR and annuloplasty procedures, all animals were followed up for additional 4 wk.

(1) MViV (n = 7): Standard MVR was successfully performed in all animals. Transvalvular pressure gradients and flow velocities were (P_max 3.77 ± 0.8 mmHg; P_mean 2.1 ± 0.6 mmHg, V_max 97 ± 13 cm/s; V_mean 68 ± 21 cm/s). Effective MViV followed (P_max 16.7 ± 1.8 mmHg; P_mean 6.2 ± 1.2 mmHg, V_max 216 ± 32 cm/s; V_mean 110 ± 24 cm/s). (2) TAC-MVR (n = 6): The overall bypass time was 177.2 ± 44.2 min. Transprosthetic P_mean was 4.6 ± 2.4 mmHg; no paravalvular leaks in all animals. (3) TAC-MV annuloplasty (n = 6): The implantation time was 47 ± 6 min. MV was competent, left ventricular ejection fraction (LV-EF%) was 63 ± 4%. (4) TViR (n = 6): Conventional TV ring repair was performed in all animals (P_max 2.42 ± 0.7 mmHg; P_mean 1.3 ± 0.6 mmHg, V_max 82 ± 10.4 cm/s; V_mean 65.4 ± 21 cm/s). All TViRs were implanted efficiently (P_max 4.7 ± 1.6 mmHg; P_mean 2.7 ± 0.8 mmHg, V_max 105 ± 31 cm/s; V_mean 81 ± 16 cm/s). A mild paravalvular leak was observed in one animal (16%).

All studied experimental valvular interventions are feasible, within the context of well-trained cardiac surgery specialists, and all possibilities should be considered when treating a patient to determine which one suits best his individual challenges and scope.