Title:
Subannular Approaches for Mitral Valve Repair to Correct Functional Mitral Regurgitation
Subannular Approaches for Mitral Valve Repair to Correct Functional Mitral Regurgitation
Author(s)
Agra, Elorm John
Advisor(s)
Muralidhar, Padala
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Abstract
Functional mitral regurgitation (FMR) is a valvular heart disease that affects 35% of the 5.5 million Americans living with heart failure. In this disease, the native geometry and mechanics of the mitral valve are distorted with increased interpapillary muscle separation, decreased closing forces, increased tethering forces on the chordae tendineae and tethered valve leaflets. FMR worsens prognosis, increases the risk of major adverse cardiac events and decreases survival. The current gold standard surgical repair for FMR is undersizing ring annuloplasty (URA) to reduce the septal-lateral dimension of the mitral annulus. Despite correcting FMR at the time of surgery, this repair has poor durability due to an unnatural configuration of the mitral valve induced by excluding the papillary muscle tips from the mitral corridor, stretching out the rough zone of the leaflets, with further tethering of the posterior leaflet. These observations led to my hypothesis that relocating the displaced papillary muscles laterally inward into the mitral corridor or basally towards the annulus will relieve leaflet tethering and improve leaflet mobility to restore native mitral valve geometry and motion. Thus, reducing the need for extensive undersizing. In this thesis, an ex vivo porcine model of FMR was developed by left ventricular resection. The implementation of subannular repairs improved leaflet mobility, reduced leaflet tethering and improved leaflet coaptation reducing the need for extensive undersizing. Approximating the papillary muscles into the mitral corridor appears to be a simple approach to relieve subvalvular tethering in functional mitral regurgitation repair.
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Date Issued
2024-06-24
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Dissertation