Tethering Distance Research Articles

Vena Contracta Width as a Predictor of Adverse Outcomes in Patients with Severe Isolated Tricuspid Regurgitation

The clinical outcomes and predictors of outcomes in isolated tricuspid regurgitation (TR) are poorly defined. The aim of this study was to investigate the determinants of outcomes in severe isolated TR. Seventy-four patients (mean age, 63 ± 12 years; 34 men) with severe isolated TR who satisfied the criteria of (1) TR jet area > 30% of right atrial area or TR jet area > 10 cm(2) and (2) a plethora of inferior vena cava or systolic flow reversal of the hepatic vein were retrospectively analyzed. The primary end points were hospitalization for worsening heart failure, tricuspid valve (TV) surgery, and cardiovascular death. During the median follow-up period of 53 months, 25 events occurred (three cardiovascular deaths, nine TV surgeries, and 13 hospitalizations for worsening heart failure). Univariate Cox analysis showed that younger age, female gender, larger effective regurgitant orifice, vena contracta width (VCW), and increased right atrial and right ventricular size were associated with cardiovascular events. Increased TV tethering distance and tethering area were also associated with cardiovascular events. In multivariate Cox regression analysis, larger VCW (hazard ratio, 1.72; 95% confidence interval, 1.15-2.57, P < 0.01) was an independent predictor of cardiovascular events. Compared with patients with VCW ≤ 7 mm, those with VCW > 7 mm had poorer long-term outcomes (adjusted hazard ratio, 19.9; P < .01). Increased VCW was also an independent predictor of cardiovascular death and TV surgery (hazard ratio, 1.2; 95% confidence interval, 1.00-1.45; P= .04). In severe isolated TR, VCW is a powerful independent predictor of adverse outcomes. Adverse outcomes were considerable for VCW > 7 mm, which suggests that quantification of TR by Doppler echocardiography is crucial for estimating prognosis. TV surgery might be considered for patients with severe isolated TR with VCW > 7 mm.

Polymer Injection Therapy to Reverse Remodel the Papillary Muscles

Background— Ischemic mitral regurgitation (MR) results from displacement of the papillary muscles caused by ischemic ventricular distortion. Progressive left ventricular (LV) remodeling has challenged therapy. Our hypothesis is that repositioning of the papillary muscles can be achieved by injection of polyvinyl-alcohol (PVA) hydrogel polymer into the myocardium in chronic MR despite advanced LV remodeling. Methods and Results— Ten sheep underwent ligation of the circumflex branches to produce chronic ischemic MR over 8 weeks. PVA was injected into the myocardium underlying the infarcted papillary muscle. Two-dimensional and 3D echocardiograms and hemodynamic data were obtained before infarct (baseline), before PVA (chronic MR), and after PVA. PVA injection significantly decreased MR from moderate to severe to trace (MR vena contracta, 5.8±1.2 to1.8±1.3 mm; chronic MR to post-PVA stage; P =0.0003). This was associated with a decrease in infarcted papillary muscle–to–mitral annulus tethering distance (30.3±5.7 to 25.9±4.6 mm, P =0.02), tenting volume (1.8±0.7 to 1.4±0.5 mL, P =0.01), and leaflet closure area (8.8±1.3 cm 2 to 7.6±1.3 cm 2 , P =0.004) from chronic MR to post-PVA stages. PVA was not associated with significant decreases in LV ejection fraction (41±3% versus 40±3%, P =NS), end-systolic elastance, τ (82±36 ms to 72±26, P =NS), or LV stiffness coefficient (0.05±0.04 to 0.03±0.01). Conclusions— PVA hydrogel injections improve coaptation and reduce remodeling in chronic MR without impairing LV systolic and diastolic function. This new approach offers a potential alternative for relieving tethering and ischemic MR by correcting papillary muscle position.

The importance of papillary muscle dyssynchrony in predicting the severity of functional mitral regurgitation in patients with non-ischaemic dilated cardiomyopathy: a two-dimensional speckle-tracking echocardiography study

In our study, we investigated the impact of papillary muscle systolic dyssynchrony (DYS-PAP) and the configuration of mitral leaflets in the prediction of significant functional mitral regurgitation (MR) with two-dimensional (2D) speckle-tracking strain analysis in non-ischaemic dilated cardiomyopathy (DCM) patients with sinus rhythm. Thirty-six non-ischaemic DCM patients (left ventricular ejection fraction <40%) with sinus rhythm were recruited. The quantification of functional MR was performed using the proximal isovelocity surface area method. The configuration of mitral leaflets [mitral annulus, coaptation height (CH), and tethering distances for papillary muscles] was evaluated in the parasternal long-axis and apical four-chamber views. The assessment of DYS-PAP was performed by applying 2D speckle-tracking imaging to the apical four-chamber view for anterolateral papillary muscle and to the apical long-axis view for posteromedial papillary muscle. Fifteen (41.6%) patients had mild MR and 21 (58.3%) patients had moderate or moderate-to-severe MR. Patients with higher levels of MR had larger mitral annulus size (P = 0.02), tethering-AL (P = 0.04), higher MR volume (P < 0.0001), effective regurgitant orifice area (P < 0.0001), and DYS-PAP (P < 0.0001) values, but lower CH (P = 0.001), global longitudinal (P = 0.005), radial (P = 0.03), and circumferential strain (P = 0.01) than those with mild MR. Receiver operating characteristic analysis was performed to assess the utility of DYS-PAP to predict moderate or moderate-to-severe functional MR. A DYS-PAP value >30 ms predicted moderate-to-severe MR with 85% sensitivity and 87% specificity [area under the curve: 0.897, 95% confidence interval (CI): 0.781-0.999, P < 0.0001]. Logistic regression analysis revealed that DYS-PAP (odds ratio: 3.2, 95% CI: 1.22-47.7, P = 0.037) was the only independent predictor of moderate or moderate-to-severe functional MR. DYS-PAP is correlated with functional MR in non-ischaemic DCM patients with sinus rhythm. A DYS-PAP cut-off value of 30 ms is a useful tool to identify patients with moderate-to-severe functional MR.

Effects of Morphologic Left Ventricular Pressure on Right Ventricular Geometry and Tricuspid Valve Regurgitation in Patients With Congenitally Corrected Transposition of the Great Arteries

Congenitally corrected transposition of the great arteries (CCTGA) is associated with tricuspid regurgitation (TR), which has been postulated to arise from the effect of ventricular septal position on the attachments of the tricuspid valve. This study was performed to determine the effect of left ventricular (LV) pressure on right ventricular (RV) and LV geometry and the degree of TR. Serial echocardiograms were reviewed from, 30 patients with CCTGA who underwent pulmonary artery banding to train the morphologic left ventricle (n = 14) or left ventricle-to-pulmonary artery conduit placement and ventricular septal defect closure in conjunction with physiologic repair (n = 16). The degree of TR, the LV/RV pressure ratio, RV and LV sphericity indexes, and tricuspid valve tethering distance and coaptation length were analyzed. After pulmonary artery banding, an increase in LV systolic pressure to > or =2/3 systemic resulted in a decrease in TR from severe to moderate (p = 0.02). The percentage of patients with severe TR decreased from 64% to 18% (p = 0.06). The RV sphericity index decreased (p = 0.05), and the LV sphericity index increased (p = 0.02). After left ventricle-to-pulmonary artery conduit placement, a decrease in LV pressure to < or =1/2 systemic resulted in an increase in TR from none to mild (p = 0.003). In conclusion, these data indicate that LV pressure in patients with CCTGA affects the degree of TR and that septal shift caused by changes in LV and RV pressure is an important mechanism.

Echocardiographic approach to the decision-making process for tricuspid valve repair

Commonly used procedures to repair functional tricuspid regurgitation have a high failure rate. The present study was designed to lower this failure rate by reducing leaflet tethering via pericardial patch augmentation when the preoperative probability of recurrence was high. Between 2001 and 2007, 210 patients with severe functional tricuspid regurgitation underwent tricuspid valve repair at the Day General Hospital. With respect to the type of repair, the patients were randomly divided into 4 groups: (1) De Vega in 52 patients; (2) ring annuloplasty in 53 patients; (3) De Vega and, if indicated by the preoperative tethering index (tethering distance > 8 mm or tethering area > 16 mm(2)), pericardial patch augmentation in 53 patients; and (4) ring annuloplasty and, if indicated by the preoperative tethering index (tethering distance > 8 mm or tethering area > 16 mm(2)), pericardial patch augmentation in 52 patients. The results of 1-month and 1-year postoperative tricuspid regurgitation were evaluated. Fifteen patients in group 3 and 15 patients in group 4 met the criterion for the complementary procedure. Postoperative tricuspid regurgitation was different between the groups (P < .05): 16.0% and 28.0% of patients in the De Vega group, 8.0% and 14.0% of patients in the ring annuloplasty group, 4.0% and 10.0% of patients in the De Vega + pericardial patch augmentation group, and 2.0% and 8.0% of patients in the ring annuloplasty + pericardial patch augmentation group had postoperative tricuspid regurgitation at 1-month and 1-year follow-up, respectively. An assessment of preoperative tricuspid valve tethering to select patients suitable for augmentation contributes to a good surgical outcome in patients with severe functional tricuspid regurgitation.

Diastolic dysfunction and left atrial enlargement as contributing factors to functional mitral regurgitation in dilated cardiomyopathy: Data from the Acorn trial

Functional mitral regurgitation (MR) is commonly seen in dilated cardiomyopathy (DCM), which may result from left ventricular (LV) dilatation and alteration in the geometric relationship of mitral valve apparatus. However, not all patients with DCM show significant MR and left atrial (LA) enlargement. The aim of this study was to assess responsible factors for developing mitral valve regurgitation. Of 300 patients enrolled in the Acorn trial, baseline echocardiography studies were available in 288, of whom 144 were excluded because of a variety of reasons. Echocardiographic data were examined for the remaining 144 patients in sinus rhythm with DCM, but without organic mitral valve disease and ischemic heart disease. Mitral regurgitation was assessed by color-flow imaging. All echocardiographic parameters were indexed to body surface area. Of 144 patients, 87 had MR grade > or =2 (group 1) and 57 had MR grade 0 or +1 (group 2). Group 1 had larger tenting area, tenting height, tethering distance, LA volume index, and mitral annular area than group 2 (all P < .001); LV volume index and ejection fraction were similar between groups. The major determinant of MR severity was tenting area (r = 0.49, P < .001), and this was best related to mitral annular area (r = 0.85, P < .001). Mitral annular area was most strongly associated with LA volume (r = 0.56, P < .001). In addition, LA volume index was highly correlated with LV diastolic dysfunction (r = 0.58, P < .001), both in total and in group 2 only. For patients with DCM in the Acorn trial, MR severity was associated with LA volume and mitral annular area but not with LV volume. Mitral annular area and LA volume were closely related, even in patients without significant MR. These findings suggest that LA enlargement caused by advanced diastolic dysfunction may contribute to causing significant MR by augmenting mitral annular dilatation in DCM.

Abstract 1104: Polymer Injection Therapy to Reverse Remodel the Papillary Muscles: Efficacy in Reducing Mitral Regurgitation in a Chronic Ischemic Model

Ischemic mitral regurgitation (IMR) relates to displacement of the papillary muscles from ischemic ventricular distortion. Recurrent IMR is frequent after annuloplasty, particularly when left ventricular remodeling continues to progress. Our hypothesis is that repositioning of the papillary muscles can be achieved by injection of polyvinyl-alcohol (PVA) polymer into the myocardium, in chronic MR with great left ventricle remodeling. Methods : we studied 8 sheep underwent ligation of circumflex branches to produce chronic ischemic MR over eight weeks. Once MR developed, PVA was injected into the myocardium underlying the infarcted PM. 2D and 3D echocardiograms were used pre infarct (baseline), pre PVA (Chronic MR) and post PVA. Hemodynamic data were obtained Results: One animal died, in the remaining 7 moderate MR developed. With PVA, the MR decreased significantly from moderate to trace-mild (vena contracta: 5.3 ± 0.9 mm vs 2.3 ± 0.9 mm, post MR vs post PVA; p&lt;0.001). This was associated with a decrease in infarcted papillary muscle-to-mitral annulus tethering distance (33.1 ± 4.6 to 27.4±4.1 mm, post MR vs post PVA, P&lt;0.05), tenting volume (2.1±0.3 to 1.6±0.4 mm, post MR vs post PVA, P&lt;0.05) and leaflet area (9.4 ± 0.8 to 8.2 ± 0.7 mm, post MR vs post PVA, P&lt;0.04). PVA was not associated with significant decreases in LVEF (41±2 % vs 39±2 %, p=ns). Conclusions : PVA polymer injections improve coaptation and reduce remodeling chronic MR without impairing LV systolic function. This new approach offers a potential alternative for relieving ischemic mitral regurgitation by correcting papillary muscle position, thus relieving tethering that causes ischemic mitral regurgitation.

A Novel Approach for Reducing Ischemic Mitral Regurgitation by Injection of a Polymer to Reverse Remodel and Reposition Displaced Papillary Muscles

Ischemic mitral regurgitation (MR) relates to displacement of the papillary muscles from ischemic ventricular distortion. We tested the hypothesis that repositioning of the papillary muscles can be achieved by injection of polyvinyl-alcohol (PVA) polymer, a biologically inert biomaterial that has been specially formulated to produce an encapsulated, stable, resilient gel once injected into the myocardium. The purpose is to materially support the infarcted myocardium while at the same time repositioning the papillary muscles that become apically tethered in MR. Nine sheep underwent ligation of circumflex branches to produce acute ischemic MR. PVA polymer was then injected by echo guidance into the myocardium underlying the infarcted papillary muscle. Hemodynamic data, left ventricular ejection fraction, elastance, tau (relaxation constant), left ventricular stiffness coefficient, and 2-dimensional and 3-dimensional echocardiograms were obtained post-MR and post-PVA injection. One animal died after coronary ligation and 2 did not develop MR. In the remaining 6, moderate MR developed. With PVA injection, the MR decreased significantly from moderate to trace-mild (vena contracta: 5+/-0.4 mm versus 2+/-0.7 mm, post-MR versus post-PVA injection; P<0.0001). This was associated with a decrease in infarcted papillary muscle-to-mitral annulus tethering distance (27+/-4 to 24+/-4 mm, post-MR versus post-PVA, P<0.001). Importantly, PVA injection was not associated with significant decreases in left ventricular ejection fraction (43+/-6% versus 37+/-4%, post-MR versus post-PVA, P=nonsignificant), elastance (3.5+/-1.4 versus 2.9+/-1.3; post-MR versus post-PVA injection, P=nonsignificant). Measures of left ventricular diastolic function, tau (100+/-51 ms to 84+/-37 ms, post-MR versus post-PVA; P=nonsignificant), and left ventricular stiffness coefficient (0.18+/-0.12 versus 0.14+/-0.08, post-MR versus post-PVA; P=nonsignificant) did not increase post-PVA. PVA polymer injection resulted in acute reverse remodeling of the ventricle with papillary muscle repositioning to decrease MR. This was not associated with an adverse effect on left ventricular systolic and diastolic function. This new approach to alter pathological anatomy after infarction may offer an alternative strategy for relieving ischemic MR by correcting the position of the affected papillary muscle, thus relieving apical tethering.

Different Mechanisms of Ischemic Mitral Regurgitation in Patients With Inferior and Anterior Myocardial Infarction

Background. Basic mechanism of ischemic mitral regurgitation (MR) is displacement of papillary muscles (PMs) due to left ventricular (LV) remodeling. Variability in LV remodeling can potentially cause heterogeneous PM displacements. The aim of this study is to compare the mitral valve complex geometry in patients with ischemic MR due to inferior and anterior myocardial infarction (MI).Methods. In 33 patients with prior inferior MI, 61 with anterior MI, and 22 controls, LV volume, mitral annular area, PM tethering distance, and MR were quantified by echocardiography.Results. Significant MR (MR fraction > 20%) was observed in 12 of the 33 with inferior MI and 7 of the 61 with anterior MI. In patients with MR due to inferior MI, tethering distance was significantly longer in medial compared to lateral PM (42.6 ± 4.9 vs. 36.1 ± 1.7 mm, p Conclusions. Although patients with ischemic MR due to inferior MI have asymmetrically predominant medial PM displacement, those with ischemic MR due to anterior MI have symmetric bilateral PM displacements.

Abstract 2265: Injection of a Biomaterial Polymer Results in Reverse Remodeling of Displaced Papillary Muscles and Reduction in Acute Ischemic Mitral Regurgitation

Ischemic mitral regurgitation (IMR) relates to papillary muscle (PM) displacement caused by left ventricular (LV) distortion. We tested the hypothesis that displaced PMs can be repositioned by injection of polyvinyl-alcohol (PVA) polymer, a biologically inert material specially formulated to produce an encapsulated, stable, resilient gel once injected into the myocardium. The aim is to alter the compliance of infarcted myocardium and realign the displaced PMs. Methods : 9 sheep underwent circumflex branch ligation to produce acute IMR. PVA polymer was then injected by echo guidance into the myocardium underlying the infarcted PM. Hemodynamic data, EF, Elastance (Emax), preload-recruitable stroke work (PRSW), relaxation constant tau, and echo data were measured post IMR and post PVA injection. Results : One animal died after coronary ligation and 2 had no IMR; MR was moderate in the remaining 6. PVA injection decreased MR vena contracta from 5±0.4mm to 2±0.7mm (p&lt;0.0001), with decreased tethering distance from infarcted PM to mitral annulus (27±4 to 24±4mm, p&lt;0.001). PVA injection did not significantly decrease EF (43±6% vs 37±4%, post IMR vs post PVA, p=ns), Emax (1.5±0.53 vs 1.6±0.42), PRSW (33±12 vs 31±5) or tau (63±49 ms vs 70±25 ms). Conclusions : PVA polymer injection can acutely reverse LV remodeling to reposition displaced PMs and decrease IMR without adverse effects on LV systolic or diastolic function. This new approach (to alter pathologic anatomy) offers an alternative for relieving IMR by correcting PM position, thus relieving tethering that causes IMR.

Reference Values Describing the Normal Mitral Valve and the Position of the Papillary Muscles

In patients with functional mitral regurgitation (MR), the principal mechanisms are insufficient coaptation due to dilatation of the mitral annulus (MA), global ventricular dysfunction with tethering of leaflets, or restricted leaflet motion with incorrect apposition due to regional ventricular dysfunction and displacement of the papillary muscles (PMs). These different entities often coexist and for this reason, knowledge of the normal reference values describing the shape and size of the MA and the position of the PMs is essential. In the present study, we describe the MA dimensions and the position of the PMs in a group of normal individuals (n = 38, 60% women, age [mean +/- SD] 51 +/- 9 years and BSA 1.83 +/- 0.16 m(2)) investigated with transthoracic echocardiography. The anteroposterior dimension (AP) of the ellipse-shaped MA was measured in a parasternal long axis, while the distance from the posteromedial (PoM) to the anterolateral (AL) commissure was measured in a parasternal short axis (CC). The annular area was calculated assuming elliptic geometry. The MA shape was described by the ratios AP/CC and AP/length of the anterior leaflet. The PMs' position was described by the following distances: (a) from the MA to the tip of the PoM and AL, PMs measured in a modified two-chamber view where both PMs could be identified, (b) the interpapillary distance, and (c) the tethering distance from the tip of the PM to the contralateral MA. These data on the normal mitral valve morphology should provide useful information when assessing the underlying mechanism of functional MR.

Autologous Myoblast Transplantation for Chronic Ischemic Mitral Regurgitation

This study was designed to assess whether post-myocardial infarction (MI) in-scar transplantation of skeletal myoblasts (SM) could reduce chronic ischemic mitral regurgitation (MR) by decreasing left ventricular (LV) remodeling. Extensive work has confirmed the relationship between ischemic MR and post-myocardial infarction (MI) remodeling of the LV. An infero-posterior MI was created in 13 sheep, thereby resulting in increasing MR. Two months post-MI, the animals were randomized and in-scar injected with expanded autologous SM (n = 6, mean: 251 x 10(6) cells) or culture medium only (n = 7). Three-dimensional echocardiography was performed at baseline, before transplantation, and for two months thereafter (sacrifice), with measurements of LV end-diastolic and end-systolic volumes (ESV), ejection fraction (EF), MR stroke volume, and leaflet tethering distance; wall motion score index (WMSi) was assessed by two-dimensional echo. Measurements were similar between groups at baseline and before transplantation. At sacrifice, transplantation was found to have reduced MR progression (regurgitant volume change: -1.83 +/- 0.32 ml vs. 5.9 +/- 0.7 ml in control group, p < 0.0001) and tethering distance (-0.41 +/- 0.09 cm vs. 0.44 +/- 0.12 cm in control group, p < 0.001), with significant improvement of EF (2.01 +/- 0.94% vs. -4.86 +/- 2.23%, p = 0.02), WMSi (-0.25 +/- 0.11 vs. 0.13 +/- 0.03 in controls, p < 0.01) and a trend to a lesser increase in ESV (23.3 +/- 3.5 ml vs. 35.4 +/- 4.2 ml in control group, p = 0.055). Autologous skeletal myoblast transplantation attenuates mild-to-moderate chronic ischemic MR, which otherwise is progressive, by decreasing tethering distance and improving EF and wall motion score, thereby enhancing valve coaptation. These data shed additional light on the mechanism by which skeletal myoblast transplantation may be cardioprotective.

Mechanism of Diastolic Mitral Regurgitation in Candidates for Cardiac Resynchronization Therapy

It was hypothesized that restricted diastolic leaflet motion is implicated not only in the mechanism of systolic mitral regurgitation (MR) but also in the mechanism of diastolic MR observed in patients with severe heart failure. Cardiac resynchronization therapy (CRT) can oppose increased mitral leaflet tethering by increasing transmitral pressure, thereby providing an opportunity to explore this hypothesis. A total of 26 consecutive candidates for CRT with diastolic MR were compared with 26 candidates without diastolic MR. Maximal diastolic mitral leaflet opening and inflow direction and measures of mitral valve apparatus (i.e., mitral annular diameters, calculated mitral annular area, and tethering distance) were assessed from the apical 4-chamber view before and during CRT. There were no significant differences in New York Heart Association functional class, ejection fraction, QRS duration, PR interval, systolic MR grade, or 2-dimensional geometry of the mitral valve apparatus between the groups. Patients with diastolic MR had more restricted maximal diastolic leaflet openings (54 degrees +/- 17 degrees vs 71 degrees +/- 11 degrees , p = 0.003) and substantially smaller inflow angles (66 degrees +/- 7 degrees vs 79 degrees +/- 9 degrees , p = 0.0003) compared with patients without diastolic MR. After the institution of CRT, diastolic MR was eliminated in all patients, although there were no significant changes in any of the parameters of mitral valve apparatus. In conclusion, abnormal mitral valve tethering is a constitutive element of the mechanism of diastolic MR in patients with left ventricular dysfunction. Its acute resolution after CRT does not seem to be caused by changes in mitral valve geometry but rather by an increase in transmitral closing forces.

Perioperative Predictors for Recurrence of Mitral Regurgitation after Surgery for Ischemic Mitral Regurgitation

Background and Objectives：In clinical practice, significant recurrence of mitral regurgitation (MR) is observed frequently even after surgical treatment for ischemic MR (IMR). The purpose of this study is to evaluate the recurrence rate of MR and to investigate perioperative predictors for its recurrence following surgery for IMR. Subjects and Methods：We retrospectively analyzed 106 patients who underwent surgical management for IMR. Echocardiographic parameters, such as severity of MR, ejection fraction, diastolic left ventricular (LV) dimension, systolic LV dimension, left atrial size, LV sphericity index, mitral valve (MV) tenting area, MV tenting height (TH), tethering distance, MV intraleaflet angle (MVILa), and MV intraleaflet height (MVILh) were measured. Results：Two types of surgery were performed to treat IMR, including valvuloplasty combined with coronary artery bypass graft (CABG)(group A, n=79) and LV volume reduction surgery combined with CABG (group B, n=27). Significant MR was detected echocardiographically 5.4±6.7 months after the surgery. The overall recurrence rate of MR was 17% (n=18), and 15.2% (n=12) in group A and 22.2% (n=6) in group B. The preoperative TH and the postoperative MVILh were independent perioperative predictors for the recurrence of significant MR according to multiple logistic regression analysis (p<0.05, respectively). Conclusion：The overall postoperative recurrence rate of significant MR after surgical repair is 17% within 6 months. Independent perioperative predictors of recurrent MR after surgery for IMR are the preoperative TH and the postoperative MVILh. For better outcomes in IMR management, those two factors should be considered in the surgical repair of IMR. (Korean Circulation J 2006;36:753-761)

Observation of Mitral Apparatus Change in Acute Ischemic Mitral Regurgitation by Live Three-Dimensional Echocardiography

Objective. Mitral apparatus geometry changes during ischemic mitral regurgitation (MR) play an important role in finding mechanisms for ischemic MR. Live three-dimensional echocardiography (L3DE) is a new technique providing cardiac full-volume image in a very short time. We applied this technique to evaluate mitral apparatus geometry changes during acute ischemic MRs.Methods. After baseline two-dimensional echocardiography (2DE) and L3DE image acquiring, the left circumflex (LCX) coronary artery distal to the first obtuse marginal artery origin was ligated in order to produce an acute ischemic MR in 10 canines. When significant ischemic MR occurred, 2DE and L3DE imagings were repeated. PM tethering distance and mitral annular geometric dilation were measured by L3DE.Results. Acute ischemic MR was successfully produced by LCX ligation in 8 canines. MR grade increased from 0.5±0.2 at baseline to 2.4±0.2 during ischemic MR in scale, P2=0.77).Conclusions. Live three-dimensional echocardiography can show mitral annulus spatial configuration and can be used to address questions related to mitral apparatus. Mitral apparatus geometry changes are contributed to acute ischemic MR.

Papillary Muscle Dysfunction Attenuates Ischemic Mitral Regurgitation in Patients With Localized Basal Inferior Left Ventricular Remodeling: Insights From Tissue Doppler Strain Imaging

The purpose of this research was to test whether papillary muscle (PM) dysfunction attenuates ischemic mitral regurgitation (MR) in patients with left ventricular (LV) remodeling of a similar location and extent. Papillary muscle dysfunction could attenuate tethering and MR because of PM elongation. However, variability in the associated LV remodeling, which exaggerates tethering, can influence the relationship between PM dysfunction and MR. In 40 patients with a previous inferior myocardial infarction but without other lesions, the LV volume, sphericity, PM tethering distance, PM longitudinal systolic strain, and MR fraction were quantified by echocardiography. The patients were divided into two groups: group 1 with significant basal inferoposterior LV bulging but without advanced LV bulging involving other territories, therefore with a similar location and extent of LV remodeling, and group 2 without significant LV bulging. The medial PM tethering distance was significantly correlated with the %MR fraction (r2 = 0.64, p < 0.01), and multiple regression analysis identified an increase in the tethering distance as the only independent determinant of the MR fraction in all subjects and also in group 1. The PM longitudinal systolic strain had no significant relationships with MR fraction in all subjects with variable degrees of LV remodeling, but it had a significant inverse correlation with the MR fraction (r2 = 0.33, p < 0.01) in group 1 with LV remodeling of a similar location and extent, indicating that PM dysfunction is associated with less MR. Papillary muscle dysfunction, reducing its longitudinal contraction to induce leaflet tethering, attenuates ischemic MR in patients with basal inferior LV remodeling.

Tricuspid Valve Tethering Predicts Residual Tricuspid Regurgitation After Tricuspid Annuloplasty

Tricuspid valve (TV) annuloplasty is recommended for functional tricuspid regurgitation (TR), which is caused by TV annulus dilatation and tethering of the leaflets. However, the impact of TV deformations on the outcome of TV annuloplasty remains unknown. The goal of this study was to investigate the relationship between preoperative TV deformation and residual TR after TV annuloplasty. Two hundred sixteen patients with functional TR had 2D echocardiography before and after TV annuloplasty. Right ventricular fractional area change and left ventricular ejection fraction were determined with the apical views. Minimal TV annulus diameter was determined by frame-by-frame analysis. The distance of TV tethering was measured from the annulus plane to the coaptation point and tethering area by tracing the leaflets from the annulus plane. TR severity was determined by the ratio of the maximal jet area to the corresponding right atrial area. The severity of residual TR was associated with age, right and left ventricular dysfunction, tethering distance and area, and severity of preoperative TR (all P<0.05). TV annular dimension was not associated with outcome of TV annuloplasty. Multivariate analysis revealed that age, tethering distance, and severity of preoperative TR (all P<0.001) were independent parameters predicting residual TR. The sensitivity and specificity in predicting residual TR after surgery were 86% and 80% for tethering distances >0.76 cm and 82% and 84% for tethering areas >1.63 cm2, respectively. Severe TV tethering predicted residual TR after TV annuloplasty, whereas preoperative TV annular dimension was not associated with outcome of TV annuloplasty.

Etiologic Evaluation of Ischemic Mitral Regurgitation Using Cardiac MRI

Background and Objectives:To evaluate the 3 dimensional geometric changes and the effect of revascularization in patients with ischemic mitral regurgitation (IMR), using cardiac magnetic resonance imaging (MRI). Subjects and Methods:Twenty-three patients with IMR, 10 with dilated cardiomyopathy with MR (DCMMR) and 7 control subjects were enrolled. Hemodynamic indices, severity of MR, geometric parameters of mitral apparatus and myocardial viability were evaluated in all patients, and re-evaluated in the IMR patients 6 months after the revascularization. Results:The mitral tenting area (TAA) (334.1±111.7 mm vs. 222.9± 123.0 mm, p=0.16) and the sum of the tenting angles (TA) (72.9±12.9°vs. 51.5±11.1°, p<0.001) at the mid-systolic phase were increased in the IMR compared to the DCM-MR patients. In the IMR patients, the MR severity was positively correlated with the sum of the tethering lengths (r=0.522, p=0.011), LVESV (r=0.551, p= 0.006), TAA (r=0.613, p=0.002) and TA (r=0.713, p<0.001). Of the 10 patients with viable myocardium, who had been revascularized without surgical repair of the mitral apparatus, the MR severity was decreased (28.3±10.4% vs. 16.5±7.6%, p=0.009) in 7 patients, with decreases in the sum of the tethering distances (51.2±13.9 mm vs. 40.2±9.1 mm, p=0.034), tenting area (299.2±93.8 mm 2 vs. 215.0±63.6 mm , p=0.036) and sum of the tenting angles (72.9±12.9° vs. 56.2±14.8°, p=0.015) 6 months after the revascularization. Conclusion:IMR was related with the geometric change in the mitral apparatus. Cardiac MRI can be an effective tool for evaluating these geometric changes and when formulating a treatment plan. (Korean Circulation J 2004;34(6):627-635)

Papillary muscle dysfunction attenuates ischemic mitral regurgitation in patients with localized basal inferior left ventricular remodeling

Objectives The purpose of this research was to test whether papillary muscle (PM) dysfunction attenuates ischemic mitral regurgitation (MR) in patients with left ventricular (LV) remodeling of a similar location and extent. Background Papillary muscle dysfunction could attenuate tethering and MR because of PM elongation. However, variability in the associated LV remodeling, which exaggerates tethering, can influence the relationship between PM dysfunction and MR. Methods In 40 patients with a previous inferior myocardial infarction but without other lesions, the LV volume, sphericity, PM tethering distance, PM longitudinal systolic strain, and MR fraction were quantified by echocardiography. The patients were divided into two groups: group 1 with significant basal inferoposterior LV bulging but without advanced LV bulging involving other territories, therefore with a similar location and extent of LV remodeling, and group 2 without significant LV bulging. Results The medial PM tethering distance was significantly correlated with the %MR fraction (r2= 0.64, p < 0.01), and multiple regression analysis identified an increase in the tethering distance as the only independent determinant of the MR fraction in all subjects and also in group 1. The PM longitudinal systolic strain had no significant relationships with MR fraction in all subjects with variable degrees of LV remodeling, but it had a significant inverse correlation with the MR fraction (r2= 0.33, p < 0.01) in group 1 with LV remodeling of a similar location and extent, indicating that PM dysfunction is associated with less MR. Conclusions Papillary muscle dysfunction, reducing its longitudinal contraction to induce leaflet tethering, attenuates ischemic MR in patients with basal inferior LV remodeling.

Reverse ventricular remodeling reduces ischemic mitral regurgitation: echo-guided device application in the beating heart.

In ischemic mitral regurgitation (MR), mitral leaflet closure is restricted by ventricular remodeling with displacement of the papillary muscles (PMs). Therapy is uncertain because ring annuloplasty does not alleviate PM displacement. We tested the hypothesis that echo-guided PM repositioning using an external device can reduce MR without compromising left ventricular (LV) function. We studied 10 sheep with ischemic MR produced by circumflex ligation with inferior infarction, 6 acutely and 4 eight weeks after myocardial infarction (MI). A Dacron patch containing an inflatable balloon was placed over the PMs and adjusted under echo guidance to reverse LV remodeling and reposition the infarcted PM. 3D echo assessed mitral valve geometric changes. In 7 sheep, sonomicrometry and Millar catheters assessed changes in end-systolic and end-diastolic pressure-volume relationships, and microspheres were injected to assess coronary flow. Moderate MR after MI resolved with patch application alone (n=3) or echo-guided balloon inflation, which repositioned the infarcted PM, decreasing the PM tethering distance from 31.1+/-2.5 mm after MI to 26.8+/-1.8 with patch (P<0.01; baseline=25.5+/-1.5). LV contractility was unchanged (end-systolic slope=3.4+/-1.6 mm Hg/mL with patch versus 2.8+/-1.6 after MI). Although there was a nonsignificant trend for a mild increase in stiffness constant (0.07+/-0.05 mL(-1) versus 0.05+/-0.03 after MI, P=0.06), LV end-diastolic pressure was unchanged as MR resolved. Coronary flow to noninfarcted regions was not reduced. An external device that repositions the PMs can reduce ischemic MR without compromising LV function. This relatively simple technique can be applied under echo guidance in the beating heart.