Abstract 234: Residual Leaflet Length as a Predictor of Tricuspid Regurgitation: An in vitro Study
Background: Severe tricuspid regurgitation (TR) is associated with increased morbidity and mortality and reduced durability of mitral valve (MV) repairs. Current treatments offer less than optimal results due to an incomplete understanding of the underlying cause. The objective of this study was to determine the mechanism by which tricuspid regurgitation occurs as an effect of annular dilatation.
Methods: Porcine tricuspid valves (N=8) were studied in an in vitro right heart simulator with an adjustable annulus under physiologic conditions. The valve dynamics were quantified starting with a normal annular size (6 cm2) and incrementally dilating up to 100%. Tricuspid regurgitation fraction (TRF) and all central residual leaflet lengths (RLL - leaflet length available for coaptation) were measured at peak systole.
Results: All valves lost competence at 40% dilatation resulting in a TRF of 11 + 4 (p < 0.05) (Fig. 1a⇓) compared to baseline and RLL of 0.5 + 0.2 cm (Fig. 1b⇓). Further dilatation resulted in linear increases in TRF. The posterior leaflet had significantly (p < 0.001) higher RLL compared to the anterior and septal leaflets, with no difference between the latter two. Posterior (p < 0.001) and anterior (p < 0.001) RLL were predictors of TRF in a multivariate regression model. In addition, posterior (r=−0.53, p < 0.001) and and anterior RLL (r=−0.61, p < 0.001) were inversely correlated with TRF.
Conclusions: The tricuspid valve is highly susceptible to regurgitation due to isolated annular dilatation even with available RLL. Insufficient RLL leads to malcoaptation at the central region resulting in TR.