Determination of the tensile mechanical properties of the segmented mitral valve annulus

Gunning, Gillian; Murphy, Bruce P.

doi:10.1016/j.jbiomech.2013.11.035

Cited by 22 publications

(17 citation statements)

References 25 publications

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“…According to our model the fatigue life of the chords in Prot et al's ''snipped'' case would be 2 Â 10 6 cycles, versus their healthy case of 2.3 Â 10 9 cycles, demonstrating that our model will predict significant reductions in fatigue life of diseased MV's. In a previous study, we investigated the distribution of mechanical properties of the mitral valve annulus, and found it to be highly irregular [21]. We also determined a particularly vulnerable and weak potion of the annulus between the right commissure and the posterior annulus.…”

Section: Discussionmentioning

confidence: 93%

Characterisation of the fatigue life, dynamic creep and modes of damage accumulation within mitral valve chordae tendineae

Gunning

Murphy

2015

Acta Biomaterialia

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Section: Discussionmentioning

confidence: 93%

Characterisation of the fatigue life, dynamic creep and modes of damage accumulation within mitral valve chordae tendineae

Gunning

Murphy

2015

Acta Biomaterialia

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“…Recent work by Gunning et al showed annular collagen is the principal driver of porcine annular mechanical strength under circumferential loading. [14] Further, they observed higher collagen content on the anterior quadrant of the annulus. However, this colorimetric analysis used an atrial view of the entire quadrant, at relatively low spatial resolution.…”

Section: Commentmentioning

confidence: 99%

“…[7–9, 12] Further uncertainty surrounds the contributions of suture technique, device size and shape, hemodynamic conditions, annular microstructure, or combinations thereof. [14–16] Developing a comprehensive understanding of these potential factors is an important step toward reducing the risk of device dehiscence, establishing optimal pre-clinical regulatory standards for future MV devices, and advancing implantation procedures.…”

mentioning

confidence: 99%

How Local Annular Force and Collagen Density Govern Mitral Annuloplasty Ring Dehiscence Risk

Pierce

Siefert

Paul

et al. 2016

The Annals of Thoracic Surgery

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Background Annuloplasty ring dehiscence is a well described mechanism of mitral valve repair failure. Defining the mechanisms underlying dehiscence may facilitate its prevention. Methods Factors governing suture dehiscence were examined using an ovine model. Following undersized ring annuloplasty in live animals (N=5), Cyclic Force (FC) acting on sutures during cardiac contraction were measured using custom transducers. FC was measured at 10 suture positions, throughout cardiac cycles with peak left ventricular pressure (LVPmax) of 100, 125, and 150mmHg. Suture pullout testing was conducted on explanted mitral annuli (N=12) to determine suture holding strength at each position. Finally, relative collagen density differences at suture sites around the annulus were assessed by two-photon excitation fluoroscopy. Results Anterior FC exceeded posterior at each LVPmax (e.g. 2.8±1.3 vs. 1.8±1.2N at LVPmax=125mmHg, p<0.01). Anterior holding strength exceeded posterior (6.4±3.6 vs. 3.9±1.6N, p<0.0001). Based on FC at LVPmax=150mmHg, margin of safety before suture pullout was vastly higher between the trigones (exclusive) versus elsewhere (4.8±0.9 versus 1.9±0.5N, p<0.001). Margin of safety exhibited strong correlation to collagen density (R2=0.947). Conclusions Despite lower cyclic loading on posterior sutures, the weaker posterior mitral annular tissue creates higher risk of dehiscence, apparently due to reduced collagen content. Sutures placed atop the trigones are less secure than predicted, due to a combination of reduced collagen and higher overall rigidity in this region. These findings highlight the inter-trigonal tissue as the superior anchor, and have implications on the design and implantation techniques for next-generation mitral prostheses.

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“…Cyclic changes in the anterior annulus’ saddle shape 4 due to aortic filling and fibrous trigone motion, as well as its denser collagen, 5 may augment overall suture tension in this region. Still, it is noteworthy that the observed force distribution was so highly concentrated on the one failed suture, even at lower LVPs.…”

Section: Discussionmentioning

confidence: 99%

Real-time recording of annuloplasty suture dehiscence reveals a potential mechanism for dehiscence cascade

Pierce

Gentile

Siefert³

et al. 2016

The Journal of Thoracic and Cardiovascular Surgery

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Determination of the tensile mechanical properties of the segmented mitral valve annulus

Cited by 22 publications

References 25 publications

Characterisation of the fatigue life, dynamic creep and modes of damage accumulation within mitral valve chordae tendineae

Characterisation of the fatigue life, dynamic creep and modes of damage accumulation within mitral valve chordae tendineae

How Local Annular Force and Collagen Density Govern Mitral Annuloplasty Ring Dehiscence Risk

Real-time recording of annuloplasty suture dehiscence reveals a potential mechanism for dehiscence cascade

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