Geometric description for the anatomy of the mitral valve: A review

Oliveira, Daniel P. S.; Srinivasan, Janaki; Espino, Daniel M.; Buchan, Keith; Dawson, Dana; Shepherd, Duncan E.T.

doi:10.1111/joa.13196

Cited by 30 publications

(17 citation statements)

References 93 publications

(249 reference statements)

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“…That being the case, an in vitro study enables individual variables to be reliably identified and manipulated which aid in objectively determining how altering a given parameter affects functionality; in our study, the data have provided evidence that strut chordae can play a role in preventing mitral regurgitation under conditions of annular dilation. The findings from this study suggest that there may be merit in further evaluating how dilation of specific segments of the annulus may link to the role of chordae in mitral valve competence; such a study would benefit from the geometry description for the mitral valve 1 .…”

Section: Discussionmentioning

confidence: 97%

“…The mitral valve is composed of the anterior and posterior leaflets and chordae tendineae which connect these leaflets to papillary muscles and in turn the left ventricle. 1 During systole, the leaflets have to cover an orifice, the circumference of which is outlined by a ring of tissue known as the mitral annulus. Closure of the mitral valve leaflets during systole prevents mitral regurgitation, enabling blood to flow out of the aortic valve and through to the aorta.…”

Section: Introductionmentioning

confidence: 99%

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The role of strut chordae in mitral valve competence during annular dilation

2020

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Strut chordae, on their own, are not typically thought to aid mitral valve competence. The aim of this study is to assess whether strut chordae aid mitral valve competence during acute annular dilation. Twelve porcine hearts were dissected and tested using an in vitro simulator, with the mitral annulus tested in either a ‘normal’ or a dilated configuration. The normal configuration included a diameter of 30 mm, a posterior leaflet ‘radius’ of 15 mm and a commissural corner ‘radius’ of 7.5 mm; the dilated annular template instead used dimensions of 50 mm, 25 mm and 12.5 mm, respectively. Each mitral valve underwent ten repeat tests with a target systolic pressure of 100 mmHg. No significant difference in the pressure was detected between the dilated and regular annuli for the mitral valves tested (95 ± 3 mmHg cf. 95 ± 2 mmHg). However, the volume of regurgitation for a dilated annulus was 28 ml greater than for a valve with a normal annulus. Following severing of strut chordae, there was a significant reduction in the systolic pressure withstood before regurgitation by mitral valves with dilated annuli (60 ± 29 mmHg cf. 95 ± 2 mmHg for normal annular dimensions; p < 0.05). In conclusion, strut chordae tendineae may play a role in aiding mitral valve competence during pathophysiology.

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Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

The role of strut chordae in mitral valve competence during annular dilation

2020

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“…Specimens were maintained hydrated throughout testing using Ringer's solution. 7,38,45 Tangent moduli (E) were calculated according to equations (1) and (2). Tangent moduli were calculated for both an initial high-extension phase and a subsequent low-extension phase for each chord.…”

Section: Materials Testingmentioning

confidence: 99%

“…Chordae tendineae connect papillary muscles, attached to the left ventricle, to the anterior and posterior leaflets of the mitral valve. 1,2 There are four types of chordae, characterised by their insertion points and corresponding geometry. 1,[3][4][5][6] Marginal chordae, which insert into the free edge of the leaflet, are often thinner and less extensible than other chordae.…”

Section: Introductionmentioning

confidence: 99%

Mechanical testing of glutaraldehyde cross-linked mitral valves. Part two: Elastic and viscoelastic properties of chordae tendineae

Constable

Northeast

Lawless

et al. 2020

Proc Inst Mech Eng H

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The aim of this study was to assess whether the mechanical properties of mitral valve chordae tendineae are sensitive to being cross-linked under load. A total 64 chordae were extracted from eight porcine hearts. Two chordae (posterior basal) from each heart were subjected to uniaxial ramp testing and six chordae (two strut, two anterior basal and two posterior basal) were subjected to dynamic mechanical analysis over frequencies between 0.5 and 10 Hz. Chordae were either cross-linked in tension or cross-linked in the absence of loading. Chordae cross-linked under load transitioned from high to low extension at a lower strain than cross-linked unloaded chordae (0.07 cf. 0.22), with greater pre-transitional (30.8 MPa cf. 5.78 MPa) and post-transitional (139 MPa cf. 74.1 MPa) moduli. The mean storage modulus of anterior strut chordae ranged from 48 to 54 MPa for cross-linked unloaded chordae, as compared to 53–61 MPa cross-linked loaded chordae. The mean loss modulus of anterior strut chordae ranged from 2.3 to 2.9 MPa for cross-linked unloaded chordae, as compared to 3.8–4.8 MPa cross-linked loaded chordae. The elastic and viscoelastic properties of chordae following glutaraldehyde cross-linking are dependent on the inclusion/exclusion of loading during the cross-linking process; with loading increasing the magnitude of the material properties measured.

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“…The mitral valve consists of anterior and posterior leaflets connected to papillary muscles by chordae tendineae. 1 Chordae restrict the motion of the leaflets to prevent the prolapse of leaflets into the left atrium during systole. 2 Thus, the mitral valve's function is to prevent blood backflow during systole (into the left atrium), while allowing unrestricted unidirectional flow during diastole; this relies on mobility, elasticity and structural integrity of the valve's leaflets.…”

Section: Introductionmentioning

confidence: 99%

Mechanical testing of glutaraldehyde cross-linked mitral valves. Part one: In vitro mechanical behaviour

Northeast

Constable

Burton

et al. 2020

Proc Inst Mech Eng H

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The aim of this study was to perform an initial assessment, in vitro, of the feasibility of using a glutaraldehyde cross-linked porcine mitral valve to retain acute functionality, focusing on assessing mitral regurgitation. Six porcine hearts were tested using an in vitro simulator. Testing was repeated following cross-linking of mitral valves; where cross-linking was achieved by placing them in a glutaraldehyde solution. The simulator enabled systolic pressure on the ventricular side of the valve to be mimicked. Following testing, mitral valve leaflets underwent Scanning Electron Microscopy of the ventricular surface of both the anterior and posterior leaflets (1 cm2 samples). The peak pressure withstood by cross-linked valves was significantly lower than for untreated valves (108 mmHg cf. 128 mmHg for untreated valves; p < 0.05). The peak pressure was typically reached 0.5 s later than for the untreated valve. While both cross-linked and untreated valves exhibited endothelium denudation, the unfixed valve had less endothelial loss. Glutaraldehyde cross-linking of porcine mitral valves may be of potential value in assessing improved bioprosthetic mitral valve replacements. However, a more immobile valve exhibiting endothelial denudation (i.e. sclerosis) was a possible concerns identified following in vitro acute assessment.

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Geometric description for the anatomy of the mitral valve: A review

Cited by 30 publications

References 93 publications

The role of strut chordae in mitral valve competence during annular dilation

The role of strut chordae in mitral valve competence during annular dilation

Mechanical testing of glutaraldehyde cross-linked mitral valves. Part two: Elastic and viscoelastic properties of chordae tendineae

Mechanical testing of glutaraldehyde cross-linked mitral valves. Part one: In vitro mechanical behaviour

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