Key result
Papillary muscle approximation plus mitral annuloplasty eliminates FMR and increases coaptation ~98% in computational models.
Why the study?
Functional mitral regurgitation is challenging to repair surgically due to the limited durability of mitral annuloplasty, prompting investigation into whether adding papillary muscle approximation improves valve biomechanics.
Does combining papillary muscle approximation and mitral annuloplasty improve mitral valve biomechanics and eliminate FMR in dilated left ventricles compared to either technique alone?
Does combining papillary muscle approximation and mitral annuloplasty improve mitral valve biomechanics and eliminate FMR in dilated left ventricles compared to either technique alone?
Computational modeling suggests that combining papillary muscle approximation with mitral annuloplasty provides superior biomechanical repair of functional mitral regurgitation compared to either technique alone.
Hypothesis-generating for combined PMA-annuloplasty in FMR models; clinical validation required before practice change.
Objectives Functional mitral regurgitation (FMR) remains challenging to repair surgically, as highlighted by the Cardiothoracic Surgical Trials Network (CTSN) trial, which showed limited durability of mitral annuloplasty. We previously demonstrated in vivo and experimentally that papillary muscle approximation (PMA) can improve mitral valve (MV) function, with or without annuloplasty. In this study, we assessed valve biomechanics after PMA, mitral annuloplasty, and their combination in imaging-derived computational models. Methods 3D echo images were obtained in three pigs with heart failure, dilated ventricles, and FMR. Each echo dataset was segmented, and a subject-specific computational model of the MV was created. Virtual FMR repair was performed on each valve using PMA, annuloplasty with true-sized (40 mm) and downsized (38 mm and 36 mm) rings, and a combination of both techniques. For each repair strategy, leaflet closure was simulated, and MV geometry and biomechanics at peak systole were evaluated. Results Isolated PMA improved valve coaptation, reduced leaflet stresses and chordal tension forces, but failed to completely eliminate FMR. Isolated mitral annuloplasty also improved coaptation, but overall provided only limited geometric and biomechanical benefits. Combining annuloplasty and PMA resulted in the most favorable outcomes, eliminating FMR, increasing coaptation length (up to 97.7%), and reducing leaflet stresses (up to 43.7%) and chordal forces (up to 43.0%). Conclusions While both PMA and annuloplasty independently improved MV function, neither technique fully resolved FMR on its own. Their combination yielded the most favorable repair outcomes, eliminating FMR and significantly improving valve geometry and biomechanics without the need for excessive annular downsizing.
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Gaidulis et al. (2026) studied Functional mitral regurgitation (n=3). Combined papillary muscle approximation (PMA) and mitral annuloplasty vs. Isolated PMA or isolated mitral annuloplasty was evaluated on Mitral valve geometry and biomechanics at peak systole. Combining papillary muscle approximation and mitral annuloplasty eliminated FMR, increased coaptation length up to 97.7%, and reduced leaflet stresses up to 43.7% in computational models.
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