New insights into mitral heart valve prolapse after chordae rupture through fluid\u2013structure interaction computational modeling

Andrés Caballero,Wei Sun,Raymond Mckay,Sabet Hashim,Wenbin Mao,Charles Primiano

doi:10.1038/s41598-018-35555-5

Abstract

Mitral valve (MV) dynamics depends on a force balance across the mitral leaflets, the chordae tendineae, the mitral annulus, the papillary muscles and the adjacent ventricular wall. Chordae rupture disrupts the link between the MV and the left ventricle (LV), causing mitral regurgitation (MR), the most common valvular disease. In this study, a fluid-structure interaction (FSI) modeling framework is implemented to investigate the impact of chordae rupture on the left heart (LH) dynamics and severity of MR. A control and seven chordae rupture LH models were developed to simulate a pathological process in which minimal chordae rupture precedes more extensive chordae rupture. Different non-eccentric and eccentric regurgitant jets were identified during systole. Cardiac efficiency was evaluated by the ratio of external stroke work. MV structural results showed that basal/strut chordae were the major load-bearing chordae. An increased number of ruptured chordae resulted in reduced basal/strut tension, but increased marginal/intermediate load. Chordae rupture in a specific scallop did not necessarily involve an increase in the stress of the entire prolapsed leaflet. This work represents a further step towards patient-specific modeling of pathological LH dynamics, and has the potential to improve our understanding of the biomechanical mechanisms and treatment of primary MR.

Highlights

Mitral valve (MV) dynamics depends on a force balance across the mitral leaflets, the chordae tendineae, the mitral annulus, the papillary muscles and the adjacent ventricular wall
Structural valve models are appropriate for simulation of quasi-static events such as closed valves, but in order to accurately model full dynamic/transient valve dynamics, an fluid-structure interaction (FSI) modeling approach that accounts for the strong coupling between the large deformation of the leaflets and the intraventricular blood flow is required[13]
Due to the complex mechanical coupling between the MV and the left ventricle (LV) mediated through the papillary muscles (PM), the chordae tendineae and the dynamic mitral annulus (MA), rigorous modeling of MV dynamics under normal and diseased states should include the entire left heart (LH) complex

Summary

Introduction

Mitral valve (MV) dynamics depends on a force balance across the mitral leaflets, the chordae tendineae, the mitral annulus, the papillary muscles and the adjacent ventricular wall. Kim et al.[8,9,10] and Sturla et al.[11,12] evaluated the biomechanical characteristics of MV models with posterior mitral leaflet (PML) prolapse, and compared different repair techniques such as neo-chordae and leaflet resection. In these FE studies, chordae structure was mainly determined from published clinical data and ex vivo findings due to the limited resolution of the medical image data. It has been determined that even with a rigid U-shaped LV model, the intraventricular mitral flow patterns are substantially different from that estimated using a tubular geometry[13]

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Conclusion