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

Circulation ◽  
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.

Minithoracotomy and Beating Heart Strategy for Mitral Surgery in Secondary Mitral Regurgitation

2019 ◽  
Vol 68 (06) ◽  
pp. 462-469 ◽  
Author(s):  
Daniel Grinberg ◽  
Matteo Pozzi ◽  
Marine Bordet ◽  
Kaled Adamou Nouhou ◽  
Young Joon Kwon ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Heart Surgery ◽  
Coronary Bypass ◽  
Hospital Length ◽  
Left Ventricular ◽  
Hospital Length Of Stay ◽  
Lv Function ◽  
Packed Red Blood Cells ◽  
Secondary Mitral Regurgitation

Background In patients with secondary mitral regurgitation (MR) associated with low ejection fraction or previous heart surgery, minimally invasive mitral valve surgery without aortic cross-clamp (MIMVS-WAC) has shown promising results. We report our experience for this strategy in our centers. Methods Between August 2011 and April 2017, 46 patients (mean age 69 ± 11 years, 76% males) received MIMVS-WAC. Indications for this technique were prior coronary bypass surgery (26%), severe or recent left ventricular (LV) dysfunction (30%), or both (39%). The mean EuroSCORE II was 12 ± 10. Results For each procedure, we conducted right minithoracotomy and hypothermic cardiopulmonary bypass (CPB) after peripheral cannulation. Mean CPB time was 159 ± 39 minutes. A mitral valve replacement (MVR) was performed in 23 cases (50%), an annuloplasty in 22 cases (48%), and a prosthesis pannus removal in 1 case (2%). Mean hospital length of stay was 12 ± 5.4 days. We report no sternotomy conversions, six reoperations for bleeding, and three deaths at 30 days. Transfusion was requested in 62% (mean infusion 2 ± 2.4 packed red blood cells). The postoperative echocardiography showed an LV function preservation in 69% of cases and a reduction of pulmonary arterial pressure in 73% of cases. Four additional deaths occurred in the long-term follow-up (mean 637 ± 381 days, median 593 days). No mitral reoperation was required, with a MR ≤ 2 in 90% of patients. Conclusion In high-risk patients, the MIMVS-WAC is a safe technique. It avoids hard dissections while ensuring excellent preservation of cardiac function.

scholarly journals Numerical Simulations of MitraClip Placement: Clinical Implications

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ramji Kamakoti ◽  
Yaghoub Dabiri ◽  
Dee Dee Wang ◽  
Julius Guccione ◽  
Ghassan S. Kassab
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Heart Surgery ◽  
Solid Mechanics ◽  
Open Heart Surgery ◽  
The Elderly ◽  
Chordae Tendineae ◽  
Particle Hydrodynamics ◽  
Smoothed Particle ◽  
Explicit Solver

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.

scholarly journals Ventricular arrhythmias in patients with functional mitral regurgitation and implantable cardiac devices: implications of mitral valve repair with Mitraclip

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
T Benito Gonzalez ◽  
X Freixa ◽  
C Godino ◽  
M Taramasso ◽  
R Estevez-Loureiro ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Mitral Valve Repair ◽  
Left Ventricular ◽  
Left Ventricular Ejection ◽  
Functional Mitral Regurgitation ◽  
Valve Repair ◽  
One Year ◽  
The Impact

Abstract Background Limited information has been reported regarding the impact of percutaneous mitral valve repair (PMVR) on ventricular arrhythmic (VA) burden. The aim of this study was to address the incidence of VA and appropriate antitachycardia implantable cardiac defibrillator (ICD) therapies before and after PMVR. Methods We retrospectively analyzed all consecutive patients with heart failure with reduce left ventricular ejection fraction, functional mitral regurgitation grade 3+ or 4+ and an active ICD or cardiac resynchronizer who underwent PMVR in any of the eleven recruiting centers. Only patients with complete available device VA monitoring from one-year before to one year after PMVR were included. Baseline clinical and echocardiographic characteristics were collected before PMVR and at 12-months follow-up. Results 93 patients (68.2±10.9 years old, male 88.2%) were enrolled. PMVR was successfully performed in all patients and device success at discharge was 91.4%. At 12-months follow-up, we observed a significant reduction in mitral regurgitation severity, NT-proBNP and prevalence of severe pulmonary hypertension and severe kidney disease. Patients also referred a significant improvement in NYHA functional class and showed a non-significant trend to reserve left ventricular remodeling. After PMVR a significant decrease in the incidence of non-sustained ventricular tachycardia (VT) (5.0–17.8 vs 2.7–13.5, p=0.002), sustained VT or ventricular fibrillation (0.9–2.5 vs 0.5–2.9, p=0.012) and ICD antitachycardia therapies (2.5–12.0 vs 0.9–5.0, p=0.033) were observed. Conclusion PMVR was related to a reduction in arrhythmic burden and ICD therapies in our cohort. Proportion of patients who presented ven Funding Acknowledgement Type of funding source: None

Surgery for Degenerative Mitral Regurgitation Valve Repair v. Valve Replacement with Chordal Preservation

1994 ◽  
Vol 2 (2) ◽  
pp. 90-94
Author(s):  
Masaharu Shigenobu ◽  
Shunji Sano
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Valve Replacement ◽  
Mitral Valve Replacement ◽  
Mitral Valve Repair ◽  
Left Ventricular ◽  
Valve Repair ◽  
Repair Group

This study compares mitral valve repair and mitral valve replacement with chordal preservation for chronic mitral regurgitation due to myxomatous degeneration with special reference to left ventricular function. Twenty-six patients underwent complete preoperative and 2 years later postoperative echocardiography study. Thirteen patients underwent mitral valve replacement associated with preservation of chordae tendineae and papillary muscles, and 13 patients had mitral valve repair. There were no statistically significant differences between the 2 groups for clinical findings, hemodynamic profiles, or left ventricular function compared prior to surgery. After correcting mitral regurgitation, increase in cardiac index was significant for the repair group. Left ventricular end-diastolic volume decreased in both groups. Left ventricular end-systolic volume significantly decreased in the repair group, but remained unchanged in the replacement group. Both ejection fraction and mean left ventricular circumferential fiber shortening velocity (mVcf) decreased in the replacement group, but significantly increased in the repair group 2 years after surgery. These findings suggest valve replacement with chordal preservation shows less improvement in ventricular systolic function late after surgery compared with mitral valve repair.

Mitral Intervention with LVAD: Preparing for Recovery

2018 ◽  
Vol 23 (1) ◽  
pp. 134-139 ◽  
Author(s):  
Cory Maxwell ◽  
George Whitener
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Left Ventricular ◽  
Assist Device ◽  
Perioperative Mortality ◽  
Ventricular Assist ◽  
Left Ventricular Assist ◽  
Practice Variability ◽  
Valve Pathology ◽  
New Evidence

Left ventricular assist device (LVAD) insertion is an increasingly common treatment of advanced heart failure. Insertion guidelines suggest regurgitant lesions of the mitral valve should not be addressed. However, recent evidence suggests that mitral regurgitation may not necessarily improve with LVAD insertion, and such patients may have worse outcomes. Thus, practice variability is high given the discrepancy between traditional thinking and new evidence that unrepaired mitral regurgitation may increase perioperative mortality. Additionally, the challenges of LVADs can make transesophageal echocardiography evaluation and assessment of mitral valve pathology difficult.

Left ventricular function after mitral valve operation in congenital mitral regurgitation

2000 ◽  
Vol 30 (6) ◽  
pp. 737
Author(s):  
Young Min Eun ◽  
Jae Young Choi ◽  
Jong Kyun Lee ◽  
Jun Hee Sul ◽  
Seung Kyu Lee ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Left Ventricular ◽  
Mitral Valve Operation ◽  
Congenital Mitral Regurgitation ◽  
Valve Operation
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