Annulus tension of the prolapsed mitral valve corrected by edge-to-edge repair

Bhattacharya, Shamik; He, Zhaoming

doi:10.1016/j.jbiomech.2011.11.005

Cited by 14 publications

(6 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous investigation on MA mechanics demonstrated the tension was lower in the commissural section (17.8 N/m) compared to anterior (40.0 N/m) or posterior (30.6 N/m) sections of the annulus (Bhattacharya and He, 2009, 2012; He and Bhattacharya, 2008, 2010). These studies offered insights into the underlying mechanism of annular dilatation.…”

Section: Introductionmentioning

confidence: 94%

Tension to passively cinch the mitral annulus through coronary sinus access: An ex vivo study in ovine model

Bhattacharya

Pham

et al. 2014

Journal of Biomechanics

Self Cite

View full text Add to dashboard Cite

Introduction The transcatheter mitral valve repair (TMVR) technique utilizes a stent to cinch a segment of the mitral annulus (MA) and reduces mitral regurgitation. The cinching mechanism results in reduction of the septal-lateral distance. However, the mechanism has not been characterized completely. In this study, a method was developed to quantify the relation between cinching tension and MA area in an ex vivo ovine model. Method The cinching tension was measured from a suture inserted within the coronary sinus (CS) vessel with one end tied to the distal end of the vessel and the other end exited to the CS ostium where it was attached to a force transducer on a linear stage. The cinching tension, MA area, septal-lateral (S-L) and commissure-commissure (C-C) diameters and leakage was simultaneously measured in normal and dilated condition, under a hydrostatic left ventricular pressure of 90 mmHg. Results The MA area was increased up to 22.8% after MA dilation. A mean tension of 2.1 ± 0.5 N reduced the MA area by 21.3 ± 5.6% and S-L diameter by 24.2 ± 5.3%. Thus, leakage was improved by 51.7 ± 16.2 % following restoration of normal MA geometry. Conclusion The cinching tension generated by the suture acts as a compensation force in MA reduction, implying the maximum tension needed to be generated by annuloplasty device to restore normal annular size. The relationship between cinching tension and the corresponding MA geometry will contribute to the development of future TMVR devices and understanding of myocardial contraction function.

show abstract

Section: Introductionmentioning

confidence: 94%

Tension to passively cinch the mitral annulus through coronary sinus access: An ex vivo study in ovine model

Bhattacharya

Pham

et al. 2014

Journal of Biomechanics

Self Cite

View full text Add to dashboard Cite

show abstract

“…In terms of the annulus, the tension is ~40 N/m at the center of the anterior annulus for a static trans-mitral pressure of 80 mmHg, which is 2–4x greater than the trans-mitral pressure existing during IVC and IVR 3, 12 . Comparatively, if we assume that the stress contribution from fluid inertia is 20 mmHg during IVC, Eq.…”

Section: Discussionmentioning

confidence: 94%

The Impact of Fluid Inertia on In Vivo Estimation of Mitral Valve Leaflet Constitutive Properties and Mechanics

Bark

Dasi

2015

Ann Biomed Eng

View full text Add to dashboard Cite

We examine the influence of the added mass effect (fluid inertia) on mitral valve leaflet stress during isovolumetric phases. To study this effect, oscillating flow is applied to a flexible membrane at various frequencies to control inertia. Resulting membrane strain is calculated through a three-dimensional reconstruction of markers from stereo images. To investigate the effect in vivo, the analysis is repeated on a published dataset for an ovine mitral valve [Journal of Biomechanics 42(16): 2697–2701]. The membrane experiment demonstrates that the relationship between pressure and strain must be corrected with a fluid inertia term if the ratio of inertia to pressure differential approaches 1. In the mitral valve, this ratio reaches 0.7 during isovolumetric contraction for an acceleration of 6 m/s2. Acceleration is reduced by 72% during isovolumetric relaxation. Fluid acceleration also varies along the leaflet during isovolumetric phases, resulting in spatial variations in stress. These results demonstrate that fluid inertia may be the source of the temporally and spatially varying stiffness measurements previously seen through inverse finite element analysis of in vivo data during isovolumetric phases. This study demonstrates that there is a need to account for added mass effects when analyzing in vivo constitutive relationships of heart valves.

show abstract

“…Previous systems in other labs have implemented precisely controlled geometry to recreate and investigate aspects of mitral valve disease in in vitro flow loops, but these studies were limited to non-sterile healthy valves without a long-term culture period. 6,25,41 In the work presented here, we aimed to replicate these advancements to better control papillary muscle positioning as well as annular diameter and shape, which allows for the first creation of mitral valve disease hemodynamics in a sterile in vitro system. By measuring and replicating the geometry of healthy valves in RUFLS, we are able to create a valve that is non-regurgitant throughout the one-week culture period.…”

Section: Discussionmentioning

confidence: 99%

Regurgitation Hemodynamics Alone Cause Mitral Valve Remodeling Characteristic of Clinical Disease States In Vitro

et al. 2015

View full text Add to dashboard Cite

Mitral valve regurgitation is a challenging clinical condition that is frequent, highly varied, and poorly understood. While the causes of mitral regurgitation are multifactorial, how the hemodynamics of regurgitation impact valve tissue remodeling is an understudied phenomenon. We employed a pseudo-physiological flow loop capable of long-term organ culture to investigate the early progression of remodeling in living mitral valves placed in conditions resembling mitral valve prolapse (MVP) and functional mitral regurgitation (FMR). Valve geometry was altered to mimic the hemodynamics of controls (no changes from native geometry), MVP (5mm displacement of papillary muscles towards the annulus), and FMR (5mm apical, 5mm lateral papillary muscle displacement, 65% larger annular area). Flow measurements ensured moderate regurgitant fraction for regurgitation groups. After 1-week culture, valve tissues underwent mechanical and compositional analysis. MVP conditioned tissues were less stiff, weaker, and had elevated collagen III and glycosaminoglycans. FMR conditioned tissues were stiffer, more brittle, less extensible, and had more collagen synthesis, remodeling, and crosslinking related enzymes and proteoglycans, including decorin, matrix metalloproteinase-1, and lysyl oxidase. These models replicate clinical findings of MVP (myxomatous remodeling) and FMR (fibrotic remodeling), indicating that valve cells remodel extracellular matrix in response to altered mechanical homeostasis resulting from disease hemodynamics.

show abstract

Annulus tension of the prolapsed mitral valve corrected by edge-to-edge repair

Cited by 14 publications

References 16 publications

Tension to passively cinch the mitral annulus through coronary sinus access: An ex vivo study in ovine model

Tension to passively cinch the mitral annulus through coronary sinus access: An ex vivo study in ovine model

The Impact of Fluid Inertia on In Vivo Estimation of Mitral Valve Leaflet Constitutive Properties and Mechanics

Regurgitation Hemodynamics Alone Cause Mitral Valve Remodeling Characteristic of Clinical Disease States In Vitro

Contact Info

Product

Resources

About