Numerical Simulations of MitraClip Placement: Clinical Implications

Abstract Mitral regurgitation (MR) is the most common type of valvular heart disease in patients over the age of 75 in the US. Despite the prevalence of mitral regurgitation in the elderly population, however, almost half of patients identified with moderate-severe MR are turned down for traditional open heart surgery due to frailty and other existing co-morbidities. MitraClip (MC) is a recent percutaneous approach to treat mitral regurgitation by placement of MC in the center of the mitral valve to reduce MR. There are currently no computational simulations to elucidate the role of MC on both the fluid and solid mechanics of the mitral valve. Here, we use the Smoothed Particle Hydrodynamics (SPH) approach to study various positional placements of the MC in the mitral valve and its impact on reducing MR. SPH is a particle based (meshless) approach that handles flow through narrow regions quite efficiently. Fluid and surrounding anatomical structure interactions is handled via contact and hence can be used for studying fluid-structure interaction problems such as blood flow with surrounding tissues/structure. This method is available as part of the Abaqus/Explicit solver. Regurgitation was initiated by removing targeted chordae tendineae that are attached to specified leaflets of the mitral valve and, subsequently, MC implants are placed in various locations, starting from the region near where the chordae tendineae were removed and moving away from the location towards the center of the valve. The MC implant location closest to where the chordae tendineae were removed showed the least amount of residual MR post-clip implantation amongst all other locations of MC implant considered. These findings have important implications for strategic placement of the MC depending on the etiology of MR to optimize clinical outcome.

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Abstract 1134: Active Adaptation of the Tethered Mitral Valve: Insights into a Compensatory Mechanism for Ischemic Mitral Regurgitation

Circulation ◽

10.1161/circ.118.suppl_18.s_649 ◽

2008 ◽

Vol 118 (suppl_18) ◽

Author(s):

Jacob P Dal-Bianco ◽

Elena Aikawa ◽

Joyce Bischoff ◽

J L Guerrero ◽

Mark D Handschumacher ◽

...

Keyword(s):

Mitral Valve ◽

Mitral Regurgitation ◽

Cell Sorting ◽

Cell Activation ◽

Heart Surgery ◽

Smooth Muscle Actin ◽

Open Heart Surgery ◽

High Stress ◽

Left Ventricular ◽

Compensatory Mechanism

Background: In patients with myocardial infarction (MI) or left ventricular (LV) dilatation, mitral regurgitation (MR) is frequently induced by leaflet tethering imposed by displaced papillary muscles (PMs), and doubles mortality. Despite this, little is known about mitral valve (MV) tissue biology and its potential to compensate for LV remodeling, which has not yet been studied prospectively. We tested the hypothesis that MV area increases over time with mechanical stretch induced by PM displacement, and as a consequence of cell activation and matrix production as opposed to passive stretching. Methods: Under cardiopulmonary bypass, the PM tips in 6 adult sheep were retracted apically short of producing MR to replicate tethering without confounding MI or turbulence. Diastolic MV leaflet area (without systolic stretch) was quantified by a new validated 3D echo algorithm at baseline and after 61±6 days, and MV tissue collected for histology (H&E, Masson) and fluorescent cell sorting at sacrifice. Data were compared with 6 unstretched sheep MVs. Results: Total diastolic MV leaflet area increased by 2.4±1.3cm2 (17±10%) from 14.3±1.9cm2 to 16.7±1.9cm2 (p<0.01) with maintained stretch, without significant change in unstretched valves despite sham open-heart surgery. Stretched MVs were 2.8 times thicker than normal (1.18±0.43 vs 0.42±0.14mm, p<0.01) due to increased spongiosa layer. Endothelial cells (CD31+) also expressing alpha-smooth muscle actin (α-SMA) were significantly more common by cell sorting in tethered versus normal leaflets (41±19% vs 9±5%, p=0.02), indicating endothelial-mesenchymal transdifferentiation (EMT); α-SMA+ positive cells indicating activation/EMT appeared in the high-stress atrial layer, penetrating into the valve interstitium, with increased collagen deposition, all absent normally. Conclusion: Mechanical stresses imposed by PM tethering increase MV leaflet area and matrix thickness, with cellular changes suggestive of reactivated embryonic valve development pathways. These findings support the concept of an actively adapting MV; understanding adaptive mechanisms can potentially provide therapeutic opportunities to augment MV area and reduce ischemic MR.

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Optimizing P2 Neochordal Length and Stability in Mitral Valve Repair With Use of a Polypropylene Loop

Texas Heart Institute Journal ◽

10.14503/thij-18-6913 ◽

2020 ◽

Vol 47 (3) ◽

pp. 207-209

Author(s):

Anil Ozen ◽

Ertekin Utku Unal ◽

Hamdi Mehmet Ozbek ◽

Gorkem Yigit ◽

Hakki Zafer Iscan

Keyword(s):

Mitral Valve ◽

Mitral Regurgitation ◽

Mitral Valve Repair ◽

Severe Mitral Regurgitation ◽

Posterior Leaflet ◽

Valve Repair ◽

Chordae Tendineae ◽

Optimal Length ◽

Precise Method ◽

Artificial Chordae

Determining the optimal length of artificial chordae tendineae and then effectively securing them is a major challenge in mitral valve repair. Our technique for measuring and stabilizing neochordae involves tying a polypropylene suture loop onto the annuloplasty ring. We used this method in 4 patients who had moderate-to-severe mitral regurgitation from degenerative posterior leaflet (P2) prolapse and flail chordae. Results of intraoperative saline tests and postoperative transesophageal echocardiography revealed only mild insufficiency. One month postoperatively, echocardiograms showed trivial regurgitation in all 4 patients. We think that this simple, precise method for adjusting and stabilizing artificial chordae will be advantageous in mitral valve repair.

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Mitral valve disease and open heart surgery in osteogenesis imperfecta tarda.

Heart ◽

10.1136/hrt.35.1.103 ◽

1973 ◽

Vol 35 (1) ◽

pp. 103-106 ◽

Cited By ~ 44

Author(s):

S J Wood ◽

J Thomas ◽

M V Braimbridge

Keyword(s):

Mitral Valve ◽

Osteogenesis Imperfecta ◽

Mitral Valve Disease ◽

Heart Surgery ◽

Open Heart Surgery ◽

Valve Disease ◽

Open Heart

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A STABLE LARGE DEFORMATION CORRECTED SPH METHOD BASED ON STABILIZED CONFORMING NODAL INTEGRATION AND LAGRANGIAN KERNELS

International Journal of Computational Methods ◽

10.1142/s0219876212500570 ◽

2012 ◽

Vol 09 (04) ◽

pp. 1250057

Author(s):

S. WANG

Keyword(s):

Large Deformation ◽

Smoothed Particle Hydrodynamics ◽

Solid Mechanics ◽

Particle Methods ◽

Sph Method ◽

Nodal Integration ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

Meshless Approximation ◽

Complex Phenomena

In this paper, we propose a Galerkin-based smoothed particle hydrodynamics (SPH) formulation with moving least-squares meshless approximation, applied to solid mechanics and large deformation. Our method is truly meshless and based on Lagrangian kernel formulation and stabilized nodal integration. The performance of the methodology proposed is tested through various simulations, demonstrating the attractive ability of particle methods to handle severe distortions and complex phenomena.

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Application of Smoothed Particle Hydrodynamics to Structural Cable Analysis

Applied Sciences ◽

10.3390/app10248983 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8983

Author(s):

A. Ersin Dinçer ◽

Abdullah Demir

Keyword(s):

Numerical Model ◽

Smoothed Particle Hydrodynamics ◽

Solid Mechanics ◽

Numerical Studies ◽

Mesh Free ◽

Longitudinal Stiffness ◽

Damping Parameter ◽

Particle Hydrodynamics ◽

Deformable Bodies ◽

Smoothed Particle

In this study, a numerical model is proposed for the analysis of a simply supported structural cable. Smoothed particle hydrodynamics (SPH)—a mesh-free, Lagrangian method with advantages for analysis of highly deformable bodies—is utilized to model a cable. In the proposed numerical model, it is assumed that a cable has only longitudinal stiffness in tension. Accordingly, SPH equations derived for solid mechanics are adapted for a structural cable, for the first time. Besides, a proper damping parameter is introduced to capture the behavior of the cable more realistically. In order to validate the proposed numerical model, different experimental and numerical studies available in the literature are used. In addition, novel experiments are carried out. In the experiments, different harmonic motions are applied to a uniformly loaded cable. Results show that the SPH method is an appropriate method to simulate the structural cable.

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Early results of a real-world series with two transapical transcatheter mitral valve replacement devices

Clinical Research in Cardiology ◽

10.1007/s00392-020-01757-z ◽

2020 ◽

Author(s):

S. Ludwig ◽

D. Kalbacher ◽

N. Schofer ◽

A. Schäfer ◽

B. Koell ◽

...

Keyword(s):

Mitral Valve ◽

Valve Replacement ◽

Mitral Valve Replacement ◽

Heart Surgery ◽

Open Heart Surgery ◽

Functional Improvement ◽

Study Cohort ◽

Early Results ◽

Transcatheter Mitral Valve Replacement

Abstract Aims Transcatheter mitral valve replacement (TMVR) with dedicated devices promises to fill the treatment gap between open-heart surgery and edge-to-edge repair for patients with severe mitral regurgitation (MR). We herein present a single-centre experience of a TMVR series with two transapical devices. Methods and results A total of 11 patients were treated with the Tendyne™ (N = 7) or the Tiara™ TMVR systems (N = 4) from 2016 to 2020 either as compassionate-use procedures or as commercial implants. Clinical and echocardiographic data were collected at baseline, discharge and follow-up and are presented in accordance with the Mitral Valve Academic Research Consortium (MVARC) definitions. The study cohort [age 77 years (73, 84); 27.3% male] presented with primary (N = 4), secondary (N = 5) or mixed (N = 2) MR etiology. Patients were symptomatic (all NYHA III/IV) and at high surgical risk [logEuroSCORE II 8.1% (4.0, 17.4)]. Rates of impaired RV function (72.7%), severe pulmonary hypertension (27.3%), moderate or severe tricuspid regurgitation (63.6%) and prior aortic valve replacement (63.6%) were high. Severe mitral annulus calcification was present in two patients. Technical success was achieved in all patients. In 90.9% (N = 10) MR was completely eliminated (i.e. no or trace MR). Procedural and 30-day mortality were 0.0%. At follow-up NYHA class was I/II in the majority of patients. Overall mortality after 3 and 6 months was 10.0% and 22.2%. Conclusions TMVR was performed successfully in these selected patients with complete elimination of MR in the majority of patients. Short-term mortality was low and most patients experienced persisting functional improvement. Graphic abstract

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ELONGATION OF MITRAL VALVE CHORDAE TENDINEAE IS ASSOCIATED WITH INCREASED LEAFLET SURFACE AREA IN PATIENTS WITH DEGENERATIVE MITRAL REGURGITATION

Journal of the American College of Cardiology ◽

10.1016/s0735-1097(15)62024-1 ◽

2015 ◽

Vol 65 (10) ◽

pp. A2024

Author(s):

Kikuko Obase ◽

Lynn Weinert ◽

Andrew Hollatz ◽

Farhan Farooqui ◽

Joseph Roberts ◽

...

Keyword(s):

Mitral Valve ◽

Mitral Regurgitation ◽

Surface Area ◽

Chordae Tendineae

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Case report of simultaneous transcatheter mitral valve-in-valve implantation and percutaneous closure of two paravalvular leaks

European Heart Journal - Case Reports ◽

10.1093/ehjcr/ytz123 ◽

2019 ◽

Vol 3 (3) ◽

Author(s):

Masahiko Asami ◽

Thomas Pilgrim ◽

Stephan Windecker ◽

Fabien Praz

Keyword(s):

Mitral Valve ◽

Heart Surgery ◽

Open Heart Surgery ◽

Transoesophageal Echocardiography ◽

Paravalvular Leak ◽

Open Heart ◽

Surgical Risk ◽

Significant Difference ◽

Valve In Valve ◽

Valve Implantation

Abstract Background Concomitant structural degeneration of surgical mitral bioprostheses and paravalvular leak (PVL) is rare but potentially fatal. Data pertaining to simultaneous transcatheter mitral valve implantation (TMVI) and percutaneous PVL closure are limited, and the optimal treatment strategy remains undetermined. We report a case of simultaneous TMVI and double percutaneous PVL closure in a patient with a degenerated bioprosthetic mitral valve and associated medial and lateral PVLs. Case summary A 75-year-old woman who underwent combined aortic (Edwards Perimount Magna 19 mm) and mitral (Edwards Perimount Magna 25 mm) surgical valve replacement 6 years ago was referred for treatment of new-onset orthopnoea and severely reduced exercise capacity. Transoesophageal echocardiography revealed severe mitral stenosis and concomitant moderate to severe mitral regurgitation, originating from two PVLs located medial and lateral from the surgical bioprosthesis. Due to high surgical risk, we performed successful transseptal mitral valve-in-valve (ViV) implantation combined with the closure of two PVLs during the same procedure. Discussion Although surgery should be considered as a first-line treatment in this setting, most patients have extremely high or prohibitive surgical risk inherent to repeat open heart surgery. Mitral ViV implantation appears a reasonable treatment option for patients with failed mitral bioprostheses. Furthermore, a recent study of percutaneous PVL closure showed no significant difference in long-term all-cause mortality compared with redo open-heart surgery. Simultaneous TMVI and percutaneous PVL closure appears feasible in selected high-risk patients.

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