Transcatheter Edge-to-Edge Treatment of Functional Tricuspid Regurgitation in an Ex Vivo Pulsatile Heart Model.

BACKGROUND: Although associated with left heart pathologies, functional tricuspid regurgitation (FTR) is often left untreated during left heart surgery. Hence, owing to its degenerative character, reoperation is often needed, encompassing an impressive (25% to 35%) mortality rate. Thus transcatheter approaches to FTR are raising great interest. OBJECTIVES: The authors evaluated the post-treatment effectiveness of the edge-to-edge technique using the percutaneous mitral valve repair device in an ex vivo pulsatile model of FTR. METHODS: The devices were implanted in 11 porcine hearts simulating FTR. In each heart, single-clip treatments involved grasping leaflet pairs in the medial or commissural position (6 combinations). Two-clip treatments were then performed considering all possible 15 combinations of leaflet pairs and medial/commissural grasping. Cardiac output, mean pulmonary pressure, and mean diastolic valve pressure gradient were evaluated in physiological and simulated pathological conditions (FTR), and post-treatments. RESULTS: Grasping the septal and anterior leaflets allowed for the best post-procedural outcome, ensuring a complete re-establishment of physiological-like hemodynamics. Septal and posterior grasping induced a significant recovery from FTR, although less marked. Conversely, grasping the anterior and posterior leaflets did not reduce FTR, and was detrimental in some specific cases. CONCLUSIONS: This experimental work demonstrated that the transcatheter edge-to-edge repair technique is a feasible approach for FTR. The study investigated this approach to develop a selective, specific structural intervention methodology for treating FTR, considering the several biomechanical factors that alter proper functionality of valvular substructures. These results can be used to guide the development of edge-to-edge repair techniques in treatment of FTR.

Measurement of strut chordal forces of the tricuspid valve using miniature C ring transducers.

Tricuspid valve (TV) leaflets, papillary muscles (PM), and tendinous chords must work together to ensure proper coaptation. Alterations in valvular mechanics, including chordal forces, may lead to improper coaptation resulting in tricuspid regurgitation. Little is known about TV mechanics as right-sided heart diseases have been overlooked. We sought to fill this gap by understanding the role of TV strut chords with the objective to understand how strut chordal force varies depending on papillary muscle (PM) origin and leaflet attachment in the normal state. Additionally we investigated how these forces are altered with abnormal geometry. Porcine TVs (n=18) were studied in a right-heart simulator capable of reproducing physiological and pathological conditions. Miniature force transducers were placed on strut chords to measure forces throughout the cardiac cycle. In the normal state, chordal force depended upon PM attachment in which chords branching from the septal PM (SPM) carried significantly less force compared to those branching from the anterior PM (APM) (p≤0.05). Annular dilatation resulted in significant increase in chordal force (p≤0.05) on all strut chords. Severe PM displacement led to increased chordal force in chords attaching the APM to the posterior leaflet as well as chords attaching the PPM to the septal leaflet. Elevated chordal force due to isolated annular dilatation was further increased only with addition of apical displacement of the APM. These results provide initial knowledge of TV chordal force mechanics and may be applied to future studies on TV repair techniques.