In Vitro Dynamic Strain Behavior of the Mitral Valve Posterior Leaflet

2005 ◽  
Vol 127 (3) ◽  
pp. 504-511 ◽  
Author(s):  
Zhaoming He ◽  
Jennifer Ritchie ◽  
Jonathan S. Grashow ◽  
Michael S. Sacks ◽  
Ajit P. Yoganathan
Keyword(s):  
Mitral Valve ◽  
Central Region ◽  
Dynamic Strain ◽  
Strain Rates ◽  
Valve Closure ◽  
Posterior Leaflet ◽  
Anterior Leaflet ◽  
Strain Behavior ◽  
Significant Difference

Knowledge of mitral valve (MV) mechanics is essential for the understanding of normal MV function, and the design and evaluation of new surgical repair procedures. In the present study, we extended our investigation of MV dynamic strain behavior to quantify the dynamic strain on the central region of the posterior leaflet. Native porcine MVs were mounted in an in-vitro physiologic flow loop. The papillary muscle (PM) positions were set to the normal, taut, and slack states to simulate physiological and pathological PM positions. Leaflet deformation was measured by tracking the displacements of 16 small markers placed in the central region of the posterior leaflet. Local leaflet tissue strain and strain rates were calculated from the measured displacements under dynamic loading conditions. A total of 18 mitral valves were studied. Our findings indicated the following: (1) There was a rapid rise in posterior leaflet strain during valve closure followed by a plateau where no additional strain (i.e., no creep) occurred. (2) The strain field was highly anisotropic with larger stretches and stretch rates in the radial direction. There were negligible stretches, or even compression (stretch<1) in the circumferential direction at the beginning of valve closure. (3) The areal strain curves were similar to the stretches in the trends. The posterior leaflet showed no significant differences in either peak stretches or stretch rates during valve closure between the normal, taut, and slack PM positions. (4) As compared with the anterior leaflet, the posterior leaflet demonstrated overall lower stretch rates in the normal PM position. However, the slack and taut PM positions did not demonstrate the significant difference in the stretch rates and areal strain rates between the posterior leaflet and the anterior leaflet. The MV posterior leaflet exhibited pronounced mechanically anisotropic behavior. Loading rates of the MV posterior leaflet were very high. The PM positions influenced neither peak stretch nor stretch rates in the central area of the posterior leaflet. The stretch rates and areal strain rates were significantly lower in the posterior leaflet than those measured in the anterior leaflet in the normal PM position. However, the slack and taut PM positions did not demonstrate the significant differences between the posterior leaflet and the anterior leaflet. We conclude that PM positions may influence the posterior strain in a different way as compared to the anterior leaflet.

In Vitro Stretches of the Mitral Valve Anterior Leaflet Under Edge-to-Edge Repair Condition

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Zhaoming He ◽  
Bo Gao ◽  
Shamik Bhattacharya ◽  
Tyler Harrist ◽  
Sibi Mathew ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Central Region ◽  
Anterior Leaflet ◽  
Flow Loop ◽  
Mitral Valves ◽  
Double Frequency ◽  
Significant Difference ◽  
Loading And Unloading ◽  
Single Suture

Mitral valve edge-to-edge repair (ETER) alters valve mechanics, which may impact efficacy and durability of the repair. The objective of this paper was to quantify stretches in the central region of the anterior leaflet of the mitral valve after ETER with a single suture and 6 mm suture. Sixteen markers, forming a 4×4 array, were attached onto the central region of the mitral valve anterior leaflet. The mitral valve was subjected to ETER with a single suture and 6 mm suture, and mounted in an in vitro flow loop simulating physiological conditions. Images of the marker array were used to calculate marker displacement and stretch. A total of 9 mitral valves were tested. Two peak stretches were observed during a cardiac cycle, one in systole and the other in diastole under mitral valve edge-to-edge repair condition. The major principal (radial) stretch during systole was significantly greater than that during diastole. However, there was no significant difference between the minor principal (circumferential) stretch during diastole and that during systole. In addition, there were no significant differences in the radial and circumferential, or areal stretches and stretch rates during diastole between the single suture and 6 mm suture. The ETER subjects the mitral valve leaflets to double frequency of loading and unloading. Minor change in suture length may not result in a significant load difference in the central region of the anterior leaflet during diastole.

Functional Dynamic In-Vivo Stresses of the Mitral Valve Anterior Leaflet

2011 ◽  
Author(s):  
Rouzbeh Amini ◽  
Chad E. Eckert ◽  
Christopher A. Carruthers ◽  
Kevin Koomalsingh ◽  
Mashito Minakawa ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Failure Modes ◽  
Dynamic Strain ◽  
Anterior Leaflet ◽  
Unloaded State ◽  
First Time ◽  
Excessive Stress

Although mitral valve (MV) repair surgeries are commonly performed, their long-term durability has not been completely satisfying. In most cases, failure was a result of disruption at the leaflet, chordae, or annular suture lines. These failure modes suggest excessive stress and the resulting tissue damage as etiologic factors. The purpose of this study was to develop a method to better estimate functional dynamic in-vivo stresses in the MV anterior leaflet (AL) midsection. The stress was computed from the dynamic in-vivo strain measured experimentally. Numerous in-vivo and in-vitro studies (e.g. [3, 4]) have been conducted to quantify MV dynamic strain. We used in-vivo strain data obtained from our well-established ovine model [4]. To calculate the in-vivo strain, we employed the actual unloaded state of the tissue as the reference frame, measured for the first time in this study. The AL stress was then computed using our nonlinear structural constitutive model [5].

scholarly journals Mitral valve opening in the ovine heart

1998 ◽  
Vol 274 (2) ◽  
pp. H552-H563 ◽  
Author(s):  
Matts O. Karlsson ◽  
Julie R. Glasson ◽  
Ann F. Bolger ◽  
George T. Daughters ◽  
Masashi Komeda ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Three Dimensional ◽  
Mitral Annulus ◽  
Posterior Leaflet ◽  
Anterior Leaflet ◽  
Rapid Fall ◽  
Valve Opening ◽  
Radiopaque Markers ◽  
Edge Separation ◽  
Central Cusp

To study the three-dimensional size, shape, and motion of the mitral leaflets and annulus, we surgically attached radiopaque markers to sites on the mitral annulus and leaflets in seven sheep. After 8 days of recovery, the animals were sedated, and three-dimensional marker positions were measured by computer analysis of biplane videofluorograms (60/s). We found that the oval mitral annulus became most elliptical in middiastole. Both leaflets began to descend into the left ventricle (LV) during the rapid fall of LV pressure (LVP), before leaflet edge separation. The anterior leaflet exhibited a compound curvature in systole and maintained this shape during opening. The central cusp of the posterior leaflet was curved slightly concave to the LV during opening. Markers at the border of the “rough zone” were separated by 10 mm during systole. We conclude that coaptation occurs very near the leaflet edges, that the annulus and leaflets move toward their open positions during the rapid fall of LVP, and that leaflet edge separation, the last event in the opening sequence, occurs near the time of minimum LVP.

Mitral Valve Posterior Leaflet Reconstruction Using Extracellular Matrix: In Vitro Evaluation

2020 ◽  
Vol 11 (4) ◽  
pp. 405-415
Author(s):  
Marcell J. Tjørnild ◽  
Søren W. Sørensen ◽  
Lisa Carlson Hanse ◽  
Søren N. Skov ◽  
Diana M. Røpcke ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Mitral Valve ◽  
Posterior Leaflet ◽  
In Vitro Evaluation

Biaxial Compliance Changes of Mitral Valve Leaflets Following Radiofrequency Ablation

2009 ◽  
Author(s):  
Carolyn G. Norwood ◽  
W. David Merryman
Keyword(s):  
Blood Flow ◽  
Radiofrequency Ablation ◽  
Mitral Valve ◽  
Left Ventricle ◽  
Left Atrium ◽  
Posterior Leaflet ◽  
Anterior Leaflet ◽  
Retrograde Blood Flow

The mitral valve (MV), located between the left atrium and left ventricle of the heart, is responsible for preventing retrograde blood flow by closing during systole. There are two MV leaflets, anterior and posterior. The anterior is the larger of the two and semicircular; the posterior leaflet is more rectangular and can be subdivided into three scallops, the middle scallop being the largest in most human hearts. The two leaflets are anchored to the wall of the left ventricle by the chordae tendinae. The MV annulus forms a complete fibrous ring anchored along the anterior leaflet (1).

Biaixal Stress–Stretch Behavior of the Mitral Valve Anterior Leaflet at Physiologic Strain Rates

2006 ◽  
Vol 34 (2) ◽  
pp. 315-325 ◽  
Author(s):  
Jonathan S. Grashow ◽  
Ajit P. Yoganathan ◽  
Michael S. Sacks
Keyword(s):  
Mitral Valve ◽  
Strain Rates ◽  
Anterior Leaflet

scholarly journals Quantifying preload alterations using a sensitive chest-mounted accelerometer

2021 ◽  
Vol 2 (4) ◽  
Author(s):  
S E Schmidt ◽  
C B Kristensen ◽  
K Soerensen ◽  
P Soegaard ◽  
R Mogelvang
Keyword(s):  
Data Analysis ◽  
Mitral Valve ◽  
Aortic Valve ◽  
Cardiac Disease ◽  
T Test ◽  
Time Interval ◽  
Valve Closure ◽  
Ejection Time ◽  
Time Intervals ◽  
Significant Difference

Abstract   Seismocardiography (SCG) is a technology where the chest wall vibrations from the beating heart are measured using a highly sensitive accelerometer. SCG offers continuous measurement of cardiac function and potential applications include remote monitoring, diagnostic assessments, prognostic health checks and biventricular pacemaker optimization. Aim In the current study we examined how changes in preload influence SCG time intervals, by acute saline infusion. Methods We included twenty-six subjects, sixteen subjects with cardiac disease such as hypertrophic cardiomyopathy, dilated cardiomyopathy, aortic valve disease or ischemic heart disease (age 45.8±17.7 years and 93% male) and ten subjects without known cardiac conditions (age 42.1±14.4 years and 70% male). SCG was recorded from the xiphoid process using a custom-made sensor before and after acute infusion saline (median 2.0 L). The SCG signals were sampled with 5000 samples per second in 60 seconds, the individual heartbeats were identified using a dedicated segmentation algorithm and an average SCG beat was computed and used for the data analysis. Using a recently proposed nomenclature the following SCG fiducial points was identified: Es which coinciding with mitral valve closure, Gs which to some degree coincides with aortic opening, Bd coinciding with aortic valve closure and Fd coinciding with mitral valve opening [1]. The Es-Gs time interval was used as a measure of isovolumetric contraction time (IVCT), the Gs-Bd time interval was used as an estimate of ejection time (ET) and the Bd-Fd time interval as an estimate of isovolumetric relaxation time (IVRT). Paired t-test was used to test for significant response after infusion, while a two sample t-test was used to test for a significant difference in the observed response in subjects with or with our cardiac disease. Results For two subjects SCG after infusion was not obtained thus, twenty-four subjects were included in the final data analysis. In the whole group, acute saline infusion shortened the IVRT (Bd-Fd) from 91.0±15.3 ms to 82.7±15.3 ms (p=0.004) and prolonged the ET (Gs-Bd) from 329.4±35 ms to 343.4±33 ms (p&lt;0.001). There was no significant change in IVCT (Es-Gs) which was 39.5±15.1 ms at baseline and 38.1±14.9 ms post-infusion (p=0.88). There was no significant difference in response between subjects with or without cardiac disease. Conclusion Increase in preload shortened the SCG time intervals related to the isovolumetric relaxation period and prolonged the period related to ejection time. SCG time intervals capture changes in preload, which demonstrates that the SCG is a potential modality for quantification of cardiac dynamics. Funding Acknowledgement Type of funding sources: None.  

scholarly journals The role of three dimensional transeosephageal echocardiography in predicting the effect of cardiac resynchronization therapy on mitral regurgitation in patients with low ejection fraction heart fail

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
A Demirtola ◽  
TS Tan ◽  
A Mammadli ◽  
IM Akbulut ◽  
I Dincer
Keyword(s):  
Heart Failure ◽  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Cardiac Resynchronization Therapy ◽  
Left Ventricular ◽  
Cardiac Resynchronization ◽  
Functional Mitral Regurgitation ◽  
Posterior Leaflet ◽  
Resynchronization Therapy ◽  
Significant Difference

Abstract Funding Acknowledgements Type of funding sources: None. Purpose Cardiac resynchronization therapy (CRT) has  a positive effect on the improvement of functional mitral regurgitation in patients with low ejection heart failure. However geometric changes in the mitral valve apparatus, subvalvular structures and their contribution to  the improvement of mitral regurgitation after CRT have not  been clearly defined. The aim of our study was to evaluate the geometric parameters of mitral valve apparatus measured with 3Dimensional (3D) transesophageal echocardiography (TEE) before CRT implantation and to determine the parameters predicting the improvement of mitral regurgitation after CRT. Methods Thirty patients with moderate or severe mitral regurgitation with low EF heart failure planned for CRT implantation and had an indication for TEE were included in the study. Effective regurgitant orifice (ERO) and regurgitant volume (RV) measurements were performed before CRT implantation. Detailed quantitative measurements of mitral valve were done from recorded images by 3D TEE. ERO, RV measurements were repeated to evaluate mitral regurgitation at the end of 3rd month. Results There were no significant changes in left ventricular EF and left ventricular diameters at the end of 3rd month, whereas ERO and RV values were decreased. A statistically significant difference was found in  posterior leaflet angle between mitral regurgitation responder and non-responder groups.  (28,93 ± 8,41 vs 41,25 ± 10,90, p = 0,006). Conclusion Heart failure patients with moderate or severe functional mitral regurgitation who underwent CRT implantation were found to have lower posterior leaflet angle measured by 3D TEE in the patient group whose mitral regurgitation improved after CRT. Abstract Figure.

Premolded Bovine Pericardial Chords for Replacement of Ruptured or Elongated Chordae Tendineae

2010 ◽  
Vol 13 (1) ◽  
pp. 17
Author(s):  
Francisco Gregori ◽  
Jo�o Carlos Leal ◽  
Domingo Marcolino Braile
Keyword(s):  
Pulmonary Embolism ◽  
Mitral Valve ◽  
Early Postoperative Period ◽  
Time Range ◽  
Mitral Insufficiency ◽  
Posterior Leaflet ◽  
Anterior Leaflet ◽  
Chordae Tendineae ◽  
Leaflet Coaptation

Background: The aim of this study was to assess by Doppler echocardiography (ECO) the functioning of the mitral valve apparatus in patients who have undergone implantation of standardized bovine pericardium chordae (SBPC) for replacement of ruptured or elongated chordae tendineae with significant thinning.Methods: SBPC were implanted in 31 patients who had mitral insufficiency due to rupture of chordae tendinae or elongated chordae with significant thinning. Patient ages ranged from 19 to 85 years (mean of 58 years). The most frequent cause of mitral insufficiency was fibroelastic degeneration in 25 patients (80.6%). The SBPC were fashioned as a set, joined at their extremities by 2 polyester-reinforced rods forming a monobloc. The SBPC were 2-mm wide and were positioned parallel to one another at a distance of 3 mm. Each set of SBPC had a corresponding measurer, and their length ranged from 20 to 35 mm. In 21 patients (67.7%) the SBPC were implanted in the posterior leaflet and in 10 patients (32.3%) in the anterior leaflet (in 2 patients concurrently in the anterior and posterior leaflets). All patients were assessed by ECO postoperatively, with a 20-month mean follow-up time (range 6-45 months).Results: One patient (3.2%) died of pulmonary embolism during the early postoperative period. Postoperative ECO showed absence of mitral regurgitation in 17 patients (54.8%), mild regurgitation in 9 (29.0%), and mild-to-moderate regurgitation in 4 (12.9%). Opening and mobility of the mitral valve were normal in the 30 surviving patients.Conclusion: The ECO revealed good functionality of the mitral valve apparatus with appropriate leaflet coaptation in patients who had undergone implantation of SBPC for replacement of ruptured or elongated and thinned chordae. A longer follow-up is required to assess absence of calcification and/or degeneration of the SBPC.

Abstract 15426: Comparison of Multimodality Imaging in Mitral Leaflet Lengths in Patients Undergoing Surgical Myectomy: A Prospective Study in Hypertrophic Obstructive Cardiomyopathy Patients

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Agostina M Fava ◽  
Anand Mehta ◽  
Barbara Bittel ◽  
Andrew Bauer ◽  
Zoran B Popovic ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Multimodality Imaging ◽  
Imaging Techniques ◽  
Ventricular Outflow Tract ◽  
Hypertrophic Obstructive Cardiomyopathy ◽  
Left Ventricular ◽  
Posterior Leaflet ◽  
Anterior Leaflet ◽  
Average Deviation ◽  
Basal Septum

Introduction: In hypertrophic obstructive cardiomyopathy (HOCM), mitral valve (MV) leaflets in often contribute to left ventricular outflow tract obstruction (LVOTO). Hence, MV assessment is crucial during surgical planning. 2 or 3-dimensional transesophageal echocardiography (2D or 3D TEE) & cardiac magnetic resonance (CMR) are used to measure MV length. Hypothesis: We sought to compare MV leaflet lengths using intraoperative TEE [2D, zoom 3D, automatic quantification of mitral valve (AMVQ)], & preoperative CMR. Methods: We prospectively studied 50 HOCM patients (59±12 years, 46% men, basal septum 18±5 mm, LVOT gradient 87 ±56 mmHg) undergoing surgical relief of LVOTO. We compared MV leaflet length on a) long-axis 2DTEE b) 3DTEE using multiplanar reconstruction c) AMVQ, EchoPAC, General Electric & d) CMR. Results: Mean anterior leaflet lengths (mm) were as follows: 2D TEE (3.3 ±0.3), 3DTEE (2.9±0.5), CMR (3.1±0.4), & AMVQ (2.9±0.5). Mean posterior leaflet lengths were 1.7±0.3, 1.7±0.4, & 1.7±0.2 & 1.9±0.4 mm, respectively. Assuming 3DTEE as the gold standard, the closest correlation for anterior leaflet was with CMR (average overestimation by CMR of 0.5 mm [root mean square deviation or RMSE% 17]), intermediate correlation with 2DTEE (average deviation of 0.6 mm [RMSE%:21]) & no correlation with AMVQ (deviation of 0.7mm [RMSE% 24]), Fig 1A-C & 2A-C. No correlation was found for posterior leaflet,Fig 1D-F & 2D-F. Conclusions: There are significant differences in measuring MV lengths using different imaging techniques. In HOCM patients undergoing surgery, precise measurement of MV leaflet lengths is crucial & extrapolation from one technique to other is not recommended.

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