Tricuspid valve maladaptation in sheep with biventricular heart failure: The posterior and septal leaflets

Tricuspid valve leaflets are dynamic tissues that can remodel in response to altered biomechanical and hemodynamic loads. The anterior, posterior, and septal leaflets exhibit distinct morphology, composition, and mechanical properties, resulting in varying in vivo strains. We hypothesized that these differences would result in leaflet-specific remodeling changes in a sheep model of biventricular heart failure. Previously, we reported significant maladaptive changes in the anterior leaflet ( Meador et al., 2020b ). Here, we extended the analysis to the posterior and septal leaflets and observed a lesser but notable remodeling response. Both the diseased posterior and septal leaflets showed increased free edge thickness and valvular interstitial cell activation. However, only the posterior leaflet exhibited increased circumferential stiffness and collagen content. In contrast, only the septal leaflet increased in area and displayed signs of endothelial-to-mesenchymal transition. These findings emphasize the importance of considering leaflet-specific remodeling when developing computational models or targeted treatment strategies for tricuspid valve disease.