Preoperative Posterior Leaflet Angle Accurately Predicts Outcome After Restrictive Mitral Valve Annuloplasty for Ischemic Mitral Regurgitation

Deleterious variants in DCHS1 are prevalent in sporadic cases of mitral valve prolapse

Background

A recent study identified DCHS1 as a causal gene for mitral valve prolapse. The goal of this study is to investigate the presence and frequency of known and novel variants in this gene in 100 asymptomatic patients with moderate to severe organic mitral regurgitation.

Methods

DNA sequencing assays were developed for two previously identified functional missense variants, namely p.R2330C and p.R2513H, and all 21 exons of DCHS1. Pathogenicity of variants was evaluated in silico.

Results

p.R2330C and p.R2513H were not identified in this cohort. Sequencing all coding regions revealed eight missense variants including six considered deleterious. This includes one novel variant (p.A2464P) and two rare variants (p.R2770Q and p.R2462Q). These variants are predicted to be deleterious with combined annotation‐dependent depletion (CADD) scores greater than 25, which are in the same range as p.R2330C (CADD = 28.0) and p.R2513H (CADD = 24.3). More globally, 24 of 100 cases were carriers of at least one in silico‐predicted deleterious missense variant in DCHS1, suggesting that this single gene may account for a substantial portion of cases.

Conclusion

This study reveals an important contribution of germline variants in DCHS1 in unrelated patients with mitral valve prolapse and supports genetic testing of this gene to screen individuals at risk.

Multi-Modality Imaging in the Evaluation and Treatment of Mitral Regurgitation

OPINION STATEMENT

Mitral regurgitation (MR) is frequent and associated with increased mortality and morbidity when severe. It may be caused by intrinsic valvular disease (primary MR) or ventricular deformation (secondary MR). Imaging has a critical role to document the severity, mechanism, and impact of MR on heart function as selected patients with MR may benefit from surgery whereas other will not. In patients planned for a surgical intervention, imaging is also important to select candidates for mitral valve (MV) repair over replacement and to predict surgical success. Although standard transthoracic echocardiography is the first-line modality to evaluate MR, newer imaging modalities like three-dimensional (3D) transesophageal echocardiography, stress echocardiography, cardiac magnetic resonance (CMR), and computed tomography (CT) are emerging and complementary tools for MR assessment. While some of these modalities can provide insight into MR severity, others will help to determine its mechanism. Understanding the advantages and limitations of each imaging modality is important to appreciate their respective role for MR assessment and help to resolve eventual discrepancies between different diagnostic methods. With the increasing use of transcatheter mitral procedures (repair or replacement) for high-surgical-risk patients, multimodality imaging has now become even more important to determine eligibility, preinterventional planning, and periprocedural guidance.

Compassionate use of the PASCAL transcatheter mitral valve repair system for patients with severe mitral regurgitation: a multicentre, prospective, observational, first-in-man study

BACKGROUND

Severe mitral regurgitation is associated with impaired prognosis if left untreated. Using the devices currently available, transcatheter mitral valve repair (TMVr) remains challenging in complex anatomical situations. We report the procedural and 30-day results of the first-in-man study of the Edwards PASCAL TMVr system.

METHODS

In this multicentre, prospective, observational, first-in-man study, we collected data from seven tertiary care hospitals in five countries that had a compassionate use programme in which patients underwent transcatheter mitral valve repair using the Edwards PASCAL TMVr system. Eligible patients were those with symptomatic, severe functional, degenerative, or mixed mitral regurgitation deemed at high risk or inoperable. Safety and efficacy of the procedure were prospectively assessed at device implantation, discharge, and 30 days after device implantation. The key study endpoints were technical success assessed at the end of the procedure and device success 30 days after implantation using the Mitral Valve Academic Research Consortium definitions.

FINDINGS

Between Sept 1, 2016, and March 31, 2017, 23 patients (median age 75 years [IQR 61-82]) had treatment for moderate-to-severe (grade 3+) or severe (grade 4+) mitral regurgitation using the Edwards PASCAL TMVr system. At baseline, the median EuroScore II score was 7·1% (IQR 3·6-12·8) and the median Society of Thoracic Surgeons predicted risk of mortality for mitral valve repair was 4·8% (2·1-9·0) and 6·8% (2·9-10·1) for mitral valve replacement. 22 (96%) of 23 patients were New York Heart Association (NYHA) class III or IV at baseline. The implantation of at least one device was successful in all patients, resulting in procedural residual mitral regurgitation of grade 2+ or less in 22 (96%) patients. Six (26%) of 23 patients had two implants. Periprocedural complications occurred in two (9%) of 23 patients (one minor bleeding event and one transient ischaemic attack). Despite the anatomical complexity of mitral regurgitation in the patients in this compassionate use cohort, technical success was achieved in 22 (96%) of 23 patients, and device success at 30 days was achieved in 18 (78%) patients. Three patients (13%) died during the 30 day follow-up. 19 (95%) of 20 patients alive 30 days after implantation were NYHA class I or II.

INTERPRETATION

This study establishes feasibility of the Edwards PASCAL TMVr system with a high rate of technical success and reduction of mitral regurgitation severity. Further research is needed on procedural and long-term clinical outcomes.

FUNDING

None.

Comparison of mitral competence after mitral repair with papillary muscle approximation versus papillary muscle relocation for functional mitral regurgitation

The purpose of this study was to evaluate the surgical results of papillary muscle approximation (PMA) and papillary muscle relocation (PMR) for functional mitral regurgitation (FMR) and to compare the effects of both procedures on the change in mitral regurgitation (MR) and echocardiogram parameters associated with tethering. Eighteen patients with moderate-to-severe FMR (MR grade ≥2) who underwent PMA or PMR were retrospectively analyzed. Underlying diseases were ischemic cardiomyopathy, idiopathic dilated cardiomyopathy, and aortic valve disease for seven, six, and five patients, respectively. Eleven patients underwent PMA and seven patients underwent PMR. Mitral annuloplasty and surgical ventricular restoration were performed concomitantly for 18 and 6 patients, respectively. None of these patients died in the hospital. Three patients died during the late period; two of these deaths were cardiac related. The rate of 3 years of freedom from cardiac-related death was 89%. After a mean follow-up of 33 months, MR grade was significantly improved compared with preoperative values (3.0 ± 0.8 to 0.7 ± 1.2; p < 0.01). Recurrence of MR grade ≥2 occurred in three patients and the rate of 3 years of freedom from recurrence of MR grade ≥2 was 87%. During follow-up, tenting height (1.1 ± 0.2 to 0.7 ± 0.2 cm; p < 0.01), tenting area (2.2 ± 0.7 to 0.9 ± 0.5 cm²; p < 0.01), and anterior leaflet tethering angle (39° ± 11° to 26° ± 8°; p < 0.01) were significantly improved compared with preoperative values. Posterior leaflet tethering angle significantly deteriorated from 40° ± 7° to 53° ± 15° (p < 0.01); however, it did not further deteriorate compared with the early postoperative value of 55° ± 16° (p = 0.7). There was no difference in echocardiogram parameters associated with tethering between PMA and PMR throughout the observation period. Both methods were associated with lasting relief of MR and reverse left ventricular remodeling. There was no difference between PMA and PMR regarding the effect on mitral valve competence. Both methods allowed durable mitral repair and good clinical outcomes.

Mitral Valve Structure in Addition to Myocardial Viability Determines the Outcome of Functional Mitral Regurgitation After Coronary Artery Bypass Grafting

BACKGROUND

Coronary artery bypass grafting (CABG) reduces functional mitral regurgitation (MR) associated with ischemic heart disease, although the predictive factors or mechanisms of reversibility of functional MR after CABG are not fully understood.We investigated whether mitral valve structure is associated with the outcome of functional MR after CABG.Methods and Results:From a consecutive series of 98 patients with mild-moderate functional MR preoperatively who underwent isolated CABG, we enrolled 66 patients who were followed up for >1 year postoperatively using echocardiography. The degree of MR was reduced in 34 patients (52%) postoperatively, in association with a lower rate of in-hospital treatment for cardiac failure in the long term, compared with the 32 patients (48%) with residual MR postoperatively. The patients with reduced MR postoperatively had longer estimated coaptation length and more anteriorly or centrally directed MR jets than those without reduced MR. On statistical analysis, the addition of estimated coaptation length and jet direction to the reported predictors (ejection fraction, left ventricular end-diastolic dimension, and tenting height) more accurately predicted changes in post-CABG MR than the reported 3 factors alone.

CONCLUSIONS

Residual MR was associated with the emergence of congestive heart failure in the long term after CABG. A specific mitral valve structure, such as large mitral leaflet size or predominant tethering of the posterior leaflet, was a predictive factor for the reversibility of post-CABG functional MR.

Impact of Left Ventricular to Mitral Valve Ring Mismatch on Recurrent Ischemic Mitral Regurgitation After Ring Annuloplasty

BACKGROUND

In ischemic mitral regurgitation (IMR), ring annuloplasty is associated with a significant rate of recurrent MR. Ring size is based on intertrigonal distance without consideration of left ventricular (LV) size. However, LV size is an important determinant of mitral valve (MV) leaflet tethering before and after repair. We aimed to determine whether LV-MV ring mismatch (mismatch of LV size relative to ring size) is associated with recurrent MR in patients with IMR after restrictive ring annuloplasty.

METHODS

Patients with moderate or severe IMR from the 2 Cardiothoracic Surgical Trials Network IMR trials who received MV repair were examined at 1 year after surgery. Baseline LV size was assessed by LV end-diastolic dimension and LV end-systolic dimension (LVESd). LV-MV ring mismatch was calculated as the ratio of LV to ring size (LV end-diastolic dimension/ring size and LVESd/ring size).

RESULTS

At 1 year after ring annuloplasty, 45 of 214 patients with MV repair (21%) had moderate or greater MR. In univariable logistic regression analysis, larger LVESd (P=0.02) and LVESd/ring size (P=0.007) were associated with recurrent MR. In multivariable models adjusted for age, sex, baseline LV ejection fraction, and severe IMR, only LVESd/ring size (odd ratio per 0.5 increase, 2.20; 95% confidence interval, 1.05-4.62; P=0.038) remained significantly associated with 1-year MR recurrence.

CONCLUSIONS

LV-MV ring size mismatch is associated with increased risk of MR recurrence. This finding may be helpful in guiding choice of ring size to prevent recurrent MR in patients undergoing MV repair and in identifying patients who may benefit from MV repair with additional subvalvular intervention or MV replacement rather than repair alone.

CLINICAL TRIAL REGISTRATION

URL:http://clinicaltrials.gov. Unique identifiers: NCT00806988 and NCT00807040.

Integrate imaging approach for minimally invasive and robotic procedures

Over the past two decades, robotic and minimally invasive cardiac surgery has been continuously refined and is currently an alternative to traditional open-heart surgery for some patients. The parallel evolution of imaging modalities has made robotic surgery safer and more efficient. Here, we review the pre- and post-operative use of computed tomography (CT) in minimally invasive and robotic cardiac procedures.

Finite Element Analysis of Patient-Specific Mitral Valve with Mitral Regurgitation

Functional mitral regurgitation (FMR) is a significant complication of left ventricular dysfunction and strongly associated with a poor prognosis. In this study, we developed a patient-specific finite element (FE) model of the mitral apparatus in a FMR patient which included: both leaflets with thickness, annulus, chordae tendineae, and chordae insertions on the leaflets and origins on the papillary muscles. The FE model incorporated human age- and gender-matched anisotropic hyperelastic material properties, and MV closure at systole was simulated. The model was validated by comparing the FE results from valve closure simulation with the in vivo geometry of the MV at systole. It was found that the FE model could not replicate the in vivo MV geometry without the application of tethering pre-tension force in the chordae at diastole. Upon applying the pre-tension force and performing model optimization by adjusting the chordal length, position, and leaflet length, a good agreement between the FE model and the in vivo model was established. Not only were the chordal forces high at both diastole and systole, but the tethering force on the anterior papillary muscle was higher than that of the posterior papillary muscle, which resulted in an asymmetrical gap with a larger orifice area at the anterolateral commissure resulting in MR. The analyses further show that high peak stress and strain were found at the chordal insertions where large chordal tethering forces were found. This study shows that the pre-tension tethering force plays an important role in accurately simulating the MV dynamics in this FMR patient, particularly in quantifying the degree of leaflet coaptation and stress distribution. Due to the complexity of the disease, the patient-specific computational modeling procedure of FMR patients presented should be further evaluated using a large patient cohort. However, this study provides useful insights into the MV biomechanics of a FMR patient, and could serve as a tool to assist in pre-operative planning for MV repair or replacement surgical or interventional procedures.

Ischemic mitral valve prolapse

Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient's outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment.

Undersized Mitral Annuloplasty Increases Strain in the Proximal Lateral Left Ventricular Wall

BACKGROUND

Recurrence of mitral regurgitation (MR) after undersized mitral annuloplasty (MA) for ischemic MR is as high as 60%, with the recurrence rate likely due to continued dilation of the left ventricle (LV). To better understand the causes of recurrent MR, we studied the effect of undersized MA on strain in the LV wall. We hypothesize that the acute change in ventricular shape induced by MA will cause increased strain in regions nearest the mitral valve.

METHODS

Finite element models were previously reported, based on cardiac magnetic resonance images of 5 sheep with mild to moderate ischemic MR. A 24-mm saddle-shaped rigid annuloplasty ring was modeled and used to simulate virtual MA. Longitudinal and myofiber strains were calculated at end-diastole and end-systole, with preoperative early diastolic geometry as the reference state.

RESULTS

The undersized MA significantly increased longitudinal strain at end-diastole in the lateral LV wall. The effect was greatest in the proximal-lateral endocardial surface, where longitudinal strain after MA was approximately triple the preoperative strain (11.17% ± 2.15% vs 3.45% ± 0.92%, p = 0.0057). In contrast, postoperative end-diastolic fiber strain decreased in this same region (2.53% ± 2.14% vs 7.72% ± 1.79%, p = 0.0060). There were no significant changes in either strain type at end-systole.

CONCLUSIONS

Undersized MA increased longitudinal strain in the proximal lateral LV wall at end-diastole. This procedure-related strain at the proximal-lateral LV wall may foster continued LV enlargement and subsequent recurrence of mitral regurgitation.

Clinical implications of mitral valve geometric alterations in children with dilated cardiomyopathy

We aimed to elucidate the relationship between severity of secondary mitral regurgitation and mitral valve geometry in children with dilated cardiomyopathy. The medical records of 16 children with dilated cardiomyopathy (median age, 1.2 years; range, 0.4-12.3 years) were reviewed. Mitral valve geometry was evaluated by measuring coaptation depth using echocardiographic apical four-chamber views at the initial presentation. Patients were dichotomised according to the mitral regurgitation severity: patients with moderate or severe secondary mitral regurgitation (n=6) and those with mild secondary mitral regurgitation (n=10). A total of 58 healthy children were considered as normal controls, and a regression equation to predict coaptation depth by body surface area was derived: coaptation depth [mm]=4.37+1.34×ln (body surface area [m2]) (residual standard error, 0.49; adjusted R2, 0.68; p<0.0001). Compared with patients with mild secondary mitral regurgitation, those with moderate or severe secondary mitral regurgitation had significantly larger coaptation depth z-scores (6.4±2.3 versus 1.9±1.4, p<0.005), larger mitral annulus diameter z-scores (3.6±2.6 versus 0.9±1.8, p<0.05), higher left ventricular sphericity index (0.89±0.07 versus 0.79±0.06, p<0.005), and greater left ventricular fraction shortening (0.15±0.05 versus 0.09±0.05, p<0.05). In conclusion, geometric alteration in the mitral valve and the left ventricle is associated with the severity of secondary mitral regurgitation in paediatric dilated cardiomyopathy, which would provide a theoretical background to surgical intervention for secondary mitral regurgitation in paediatric populations.

Transapical Coaptation Plate for Functional Mitral Regurgitation: An In Vitro Study

A novel transapical coaptation plate (TCP) device was developed and anchored by sutures in the mitral valve to treat functional mitral regurgitation. The objective of this study was to test efficacy of the TCP in an in vitro model. Eight fresh porcine mitral valves were mounted in a left heart simulator to simulate functional mitral regurgitation by means of annular dilatation and asymmetrical or symmetrical papillary muscle (PM) displacement. Six polyurethane TCPs in thickness of 6.4(#1), 4.8(#2), 3.2(#3) mm and hardness of durometer 30 A (H) and 30 OO(S),were fabricated and labeled as H1, H2, H3 and S1, S2, S3, respectively. These TCPs were anchored by the sutures in the mitral annulus and left ventricle apex, and tested. Steady backward flow leakage in a hydrostatic condition and regurgitant volume in a pulsatile flow were measured before and after implantation of the TCPs. Mean regurgitant volume fractions in the asymmetric PM displacement were reduced significantly from 59.1 to 37.2% for H1, 43.2% for H2, 35.9% for S1 and 34.2% for S2 (p < 0.021), after implantation of the TCPs. No significant reduction in mitral regurgitation was seen for H3 and S3 (p > 0.067). Mitral regurgitation was mild in the symmetric PM displacement, and was not significantly reduced after implantation of the TCPs. In conclusion, the TCP anchored by the sutures in the mitral annulus and left ventricle apex functions successfully as a plug in the mitral valve leaflet gap. The TCP with thickness equal to or greater than 4.8 mm is effective to reduce functional mitral regurgitation. The TCP hardness has no effect on difference in reduction of functional mitral regurgitation.

Impact of mitral geometry and global afterload on improvement of mitral regurgitation after trans-catheter aortic valve implantation

Objective

To assess the impact of mitral geometry, left ventricular (LV) remodelling and global LV afterload on mitral regurgitation (MR) after trans-catheter aortic valve implantation (TAVI).

Methods

In this study, 60 patients who underwent TAVI were evaluated by 3D echocardiography at baseline, 1 month and 6 months after procedure. The proportional change in MR following TAVI was determined by examining the percentage change in vena contracta (VC) at 6 months. Patients having a significant reduction of at least 30% in VC were defined as good responders (GR) and the remaining patients were defined as poor responders (PR).

Results

After 6 months of TAVI, 27 (45%) patients were GR and 33 (55%) were PR. There was a significant decrease in 3DE-derived mitral annular diameter and area (P = 0.001), mitral valve tenting area (TA) (P = 0.05), and mitral papillary muscle dyssynchrony index (DSI) (P = 0.05) in the GR group. 3DE-derived LVESV (P = 0.016), LV mass (P = 0.001) and LV DSI, (P = 0.001) were also improved 6 months after TAVI. In addition, valvulo-arterial impedance (ZVA) was significantly higher at baseline in patients with PR (P = 0.028). 3DE-derived mitral annular area (β: 0.47, P = 0.04), mitral papillary DSI (β: −0.65, P = 0.012) and ZVA (β: 0.45, P = 0.028) were the strongest independent parameters that could predict the reduction of functional MR after TAVI.

Conclusion

GR patients demonstrate more regression in mitral annulus area and diameter after significant decrease in high LVEDP and trans-aortic gradients with TAVI. PR patients appear to have increased baseline ZVA, mitral valve tenting and restriction in mitral valve coaptation. These factors are important for predicting the impact of TAVI on pre-existing MR.

The value of preoperative 3-dimensional over 2-dimensional valve analysis in predicting recurrent ischemic mitral regurgitation after mitral annuloplasty

OBJECTIVES

Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.

METHODS

Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation. Two-dimensional echocardiography annular diameter and tethering parameters were measured in the apical 2- and 4-chamber views. A customized protocol was used to assess 3-dimensional annular geometry and regional leaflet tethering. Recurrence (grade ≥2) was assessed with 2-dimensional transthoracic echocardiography at 6 months.

RESULTS

Preoperative 2- and 3-dimensional annular geometry were similar in all patients with ischemic mitral regurgitation. Preoperative 2- and 3-dimensional leaflet tethering were significantly higher in patients with recurrence (n = 13) when compared with patients without recurrence (n = 37). Multivariate logistic regression revealed preoperative 2-dimensional echocardiography posterior tethering angle as an independent predictor of recurrence with an optimal cutoff value of 32.0° (area under the curve, 0.81; 95% confidence interval, 0.68-0.95; P = .002) and preoperative 3-dimensional echocardiography P3 tethering angle as an independent predictor of recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84-1.00; P < .001). The predictive value of the 3-dimensional geometric multivariate model can be augmented by adding basal aneurysm/dyskinesis (area under the curve, 0.94; 95% confidence interval, 0.87-1.00; P < .001).

CONCLUSIONS

Preoperative 3-dimensional echocardiography P3 tethering angle is a stronger predictor of ischemic mitral regurgitation recurrence after annuloplasty than preoperative 2-dimensional echocardiography posterior tethering angle, which is highly influenced by viewing plane. In patients with a preoperative P3 tethering angle of 29.9° or larger (especially when combined with basal aneurysm/dyskinesis), chordal-sparing valve replacement should be strongly considered.

The use of imaging in new transcatheter interventions: an EACVI review paper

Transcatheter therapies for the treatment of valve heart diseases have expanded dramatically over the last years. The new developments and improvements in devices and techniques, along with the increasing expertise of operators, have turned the catheter-based approaches for valvular disease into an established treatment option. Various imaging techniques are used during these procedures, but echocardiography plays an essential role during patient selection, intra-procedural monitoring, and post-procedure follow-up. The echocardiographic assessment of patients undergoing transcatheter interventions places demands on echocardiographers that differ from those of the routine evaluation of patients with valve disease, and there is a need for specific expertise for those working in the cath lab. In the context of the current rapid developments and growing use of transcatheter valve therapies, this document intends to update the previous recommendations and address new advancements in imaging, particularly for those involved in any stage of the treatment of patients with valvular heart diseases.

A Comparison of 2 Mitral Annuloplasty Rings for Severe Ischemic Mitral Regurgitation: Clinical and Echocardiographic Outcomes

Controversies regarding the choice of annuloplasty rings for treatment of ischemic mitral regurgitation still exist. Aim of the study is to compare early performance of 2 different rings in terms of rest and exercise echocardiographic parameters (transmitral gradient, systolic pulmonary artery pressure, and mitral valve area), clinical outcomes, and recurrence of mitral regurgitation. From January 2008 till December 2013, prospectively collected data of patients who underwent coronary artery bypass grafting and undersizing mitral valve annuloplasty for severe chronic ischemic mitral regurgitation at our Institution were reviewed. A total of 93 patients were identified; among them 44 had semirigid Memo 3D ring implanted (group A) whereas 49 had a rigid profile 3D ring (group B). At 6 months, recurrent ischemic mitral regurgitation, equal or more than moderate, was observed in 4 and 6 patients in the group A and B, respectively (P = 0.74). Group A showed certain improved valve geometric parameters such as posterior leaflet angle, tenting area, and coaptation depth. Transmitral gradient was significantly higher at rest in the group B (P < 0.0001). During exercise, significant increase of transmitral gradient and systolic pulmonary artery pressure was observed in group B (P < 0.0001). Mitral valve area was not statistically significantly smaller at rest in between groups (P = 0.09); however, it significantly decreased with exercise in group B (P = 0.01). At midterm follow-up, patients in group B were more symptomatic. In patients with chronic ischemic mitral regurgitation, use of semirigid Memo 3D ring when compared to the rigid Profile 3D may be associated with early improved mitral valve geometrical conformation and hemodynamic profile, particularly during exercise. No difference was observed between both groups in recurrent mitral regurgitation.

Mitral valve repair for ischemic mitral regurgitation: lessons from the Cardiothoracic Surgical Trials Network randomized study

Approximately 30% to 50% of patients will develop ischemic mitral regurgitation (MR) after a myocardial infarction, which is a result of progressive left ventricular remodeling and dysfunction of the subvalvular apparatus, and portends a poor long-term prognosis. Surgical treatment is centered on mitral valve repair utilizing a restrictive annuloplasty, or valve replacement with preservation of the subvalvular apparatus. In the recent Cardiothoracic Surgical Trials Network (CSTN) study, patients with severe ischemic MR were randomized to mitral valve repair with a restrictive annuloplasty versus chordal-sparing valve replacement, and concomitant coronary artery bypass grafting, if indicated. At 2-year follow-up, mitral valve repair was associated with a significantly higher incidence of moderate or greater recurrent MR and heart failure, with no difference in the indices of left ventricular reverse remodeling, as compared with valve replacement. The current appraisal aims to provide insight into the CSTN trial results, and discusses the evidence supporting a pathophysiologic-guided repair strategy incorporating combined annuloplasty and subvalvular repair techniques to optimize the outcomes of mitral valve repair in ischemic MR.

Two-Year Outcomes of Surgical Treatment of Severe Ischemic Mitral Regurgitation

BACKGROUND

In a randomized trial comparing mitral-valve repair with mitral-valve replacement in patients with severe ischemic mitral regurgitation, we found no significant difference in the left ventricular end-systolic volume index (LVESVI), survival, or adverse events at 1 year after surgery. However, patients in the repair group had significantly more recurrences of moderate or severe mitral regurgitation. We now report the 2-year outcomes of this trial.

METHODS

We randomly assigned 251 patients to mitral-valve repair or replacement. Patients were followed for 2 years, and clinical and echocardiographic outcomes were assessed.

RESULTS

Among surviving patients, the mean (±SD) 2-year LVESVI was 52.6±27.7 ml per square meter of body-surface area with mitral-valve repair and 60.6±39.0 ml per square meter with mitral-valve replacement (mean changes from baseline, -9.0 ml per square meter and -6.5 ml per square meter, respectively). Two-year mortality was 19.0% in the repair group and 23.2% in the replacement group (hazard ratio in the repair group, 0.79; 95% confidence interval, 0.46 to 1.35; P=0.39). The rank-based assessment of LVESVI at 2 years (incorporating deaths) showed no significant between-group difference (z score=-1.32, P=0.19). The rate of recurrence of moderate or severe mitral regurgitation over 2 years was higher in the repair group than in the replacement group (58.8% vs. 3.8%, P<0.001). There were no significant between-group differences in rates of serious adverse events and overall readmissions, but patients in the repair group had more serious adverse events related to heart failure (P=0.05) and cardiovascular readmissions (P=0.01). On the Minnesota Living with Heart Failure questionnaire, there was a trend toward greater improvement in the replacement group (P=0.07).

CONCLUSIONS

In patients undergoing mitral-valve repair or replacement for severe ischemic mitral regurgitation, we observed no significant between-group difference in left ventricular reverse remodeling or survival at 2 years. Mitral regurgitation recurred more frequently in the repair group, resulting in more heart-failure-related adverse events and cardiovascular admissions. (Funded by the National Institutes of Health and Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00807040.).

Recent developments in percutaneous mitral valve treatment

In recent years, various percutaneous techniques have been introduced for the treatment of mitral regurgitation (MR), including direct leaflet repair, annuloplasty and left ventricular remodeling. Percutaneous mitral repair targets both primary degenerative and secondary mitral valve regurgitation and may be considered in selected high-surgical-risk patients. The assessment of mitral functional anatomy by echocardiography and computed tomography is crucial when selecting the appropriate repair strategy, according to the regurgitant valve lesion and the surrounding anatomy. The ongoing clinical use of new devices in annuloplasty and percutaneous mitral valve replacement is a promising new scenario in the treatment of MR that goes beyond the conventional surgical approach.

Double row of overlapping sutures for downsizing annuloplasty decreases the risk of residual regurgitation in ischaemic mitral valve repair

OBJECTIVES

The aim of this study was to evaluate a novel insertion technique of the prosthetic ring that would further magnify the degree of annulus narrowing, thereby reducing the potential for a residual leak in ischaemic mitral valve repair.

METHODS

Thirty-six patients with ischaemic mitral regurgitation (MR) were randomly assigned into two groups. In 18 patients, the prosthetic ring was inserted in the conventional manner with a single row of sutures (control group). In the remaining 18 patients, the ring was attached using a double row of sutures tied both on the inner and on the outer part of the sewing cuff. Both groups had similar preoperative clinical and echocardiographic characteristics with severe leaflet tethering: mean tenting area >2.5 cm(2), mean anterior leaflet angle >25° and posterior leaflet angle >45°. The mean prosthetic ring sizes inserted in both groups were identical (mean: 27.3 mm).

RESULTS

At 12 months, there was no clinical event except for 1 rehospitalization in the control group. The mean mitral regurgitation grade was higher in the control group than in the group with the double row of sutures at 1.6 ± 0.9 vs 0.7 ± 0.3 (P = 0.0003). Annulus diameter reduction was less pronounced in the control group when compared with the group with the double row of sutures, both in the parasternal long-axis: 29.3 ± 3 vs 26.3 ± 3 mm (P = 0.0003) and in apical four-chamber views: 31 ± 3 vs 28 ± 2 mm (P = 0.003). Leaflet tethering indices were greater in the control group than in the group with the double row of sutures: tenting area: 1.42 ± 0.3 vs 1.1 ± 0.5 cm(2) (P = 0.002), anterior leaflet angle: 33 ± 3° vs 28 ± 5° (P = 0.0009) and posterior leaflet angle: 110 ± 13° vs 80 ± 11° (P = 0.0001). Left ventricular function parameters were not statistically different among the two groups.

CONCLUSION

A double row of overlapping sutures for attaching the prosthetic ring in downsizing annuloplasty is more efficient in narrowing the mitral annulus than the conventional technique in ischaemic mitral repair. Even in high-risk patients whose leaflets were severely tethered on echocardiography, it almost eliminated the risk of MR recurrence in this study.

Successful first-in-man Melody transcatheter valve implant in a dehisced mitral annuloplasty ring transapical valve-in-ring implant

AIMS

A "valve-in-ring" (ViR) procedure involves the transcatheter implant of a valved stent in a prosthetic mitral ring. The presence of a partial dehiscence of the prosthetic ring is a major contraindication for a ViR due to inefficacious sealing. We describe an alternative method of ViR implant to achieve proper valve sealing in the case of ring dehiscence.

METHODS AND RESULTS

A 76-year-old male patient suffered from severe central mitral regurgitation due to annuloplasty ring dehiscence and leaflet tethering. ECG-gated multidetector computed tomography was used for preoperative planning. Standard transapical access was gained through a minimally invasive left thoracotomy in the 5th intercostal space. A customised Melody valve with two PTFE sutures fixed to the apex was used. The intervention was performed without complications, the patient recovered well, and transthoracic echo revealed no mitral regurgitation through the implanted valve with a transvalvular gradient of 4 mmHg.

CONCLUSIONS

The implantation of a long covered stent such as the Melody valve allows successful sealing following a ViR even in case of partially detached annuloplasty rings. This procedure is a proof of concept that proper sealing can be achieved at the leaflet level without the use of radial force at the annular level.

Quantitative Assessment of Mitral Apparatus Geometry Using Dual-Source Computed Tomography in Mitral Regurgitation

To quantitatively assess the geometric changes in mitral valve apparatus in mitral regurgitation (MR) by dualsource computed tomography (DSCT) and to analyze its impact on MR.The study subjects consisted of 20 controls, 20 patients with mild MR, and 30 patients with moderate to severe MR, all of whom underwent DSCT. The geometric parameters of the mitral valve were measured by CT and compared among the 3 groups. The correlations between DSCT measurements and MR severity were also analyzed.As regurgitation worsened, our results showed progressive enlargements of the mitral annular area, anteroposterior diameter, and mitral valve tenting area at the central level. Moreover, a higher mitral valve sphericity index and longer distance between the heads of the papillary muscles reflected a more outward displacement of the papillary muscles. The mitral annular area and tenting area at the central level had strong correlations with regurgitation severity.DSCT is available to quantitatively assess mitral valve morphology and provide additional information regarding its geometry. The mitral annular area and tenting area at the central level were the strongest determinants of MR severity.

A novel coaptation plate device for functional mitral regurgitation: an in vitro study

A novel mitral valve repair device, coaptation plate (CP), was proposed to treat functional mitral regurgitation. The objective of this study was to test efficacy of the CP in an in vitro model of functional mitral regurgitation. Ten fresh porcine mitral valves were mounted in a left heart simulator, Mitral regurgitation was emulated by means of annular dilatation, and the asymmetrical or symmetrical papillary muscles (PM) displacement. A rigid and an elastic CPs were fabricated and mounted in the orifice of regurgitant mitral valves. Steady flow leakage in a hydrostatic condition and regurgitant volume in a pulsatile flow were measured before and after implantation of the CPs. The rigid and elastic CPs reduced mitral valve regurgitant volume fraction from 60.5 ± 11.4 to 35 ± 11.6 and 36.5 ± 9.9%, respectively, in the asymmetric PM displacement. Mitral regurgitation was much lower in the symmetric PM displacement than in the asymmetric PM displacement, and was not significantly reduced after implantation of either CP. In conclusion, both the rigid and elastic CPs are effective and have no difference in reduction of functional mitral regurgitation. The CP does not aggravate mitral valve coaptation and may be used as a preventive way.

Determinants of functional capacity after mitral valve annuloplasty or replacement for ischemic mitral regurgitation

OBJECTIVE

To identify the exercise echocardiographic determinants of long-term functional capacity, in patients with chronic ischemic mitral regurgitation, after restrictive mitral valve annuloplasty (RMA) or mitral valve replacement (MVR).

METHODS

We retrospectively analyzed 121 patients with significant chronic ischemic mitral regurgitation, who underwent RMA (n = 62) or MVR (n = 59), between 2005 and 2011. Preoperatively, all patients underwent a resting echocardiographic examination, and a 6-minute walking test (6-MWT) to measure distance. Resting and exercise stress echocardiography, and the 6-MWT were repeated at 41 ± 16.5 months.

RESULTS

After surgery, the 6-MWT distance significantly improved in the MVR group, and decreased in the RMA group (+37 ± 39 m vs -24 ± 49 m, respectively; P < .0001). Exercise indexed effective orifice area was significantly higher in the MVR, versus the RMA, group (MVR: change from 1.3 ± 0.2 cm(2)/m(2) to 1.5 ± 0.3 cm(2)/m(2); RMA: change from 1.1 ± 0.3 cm(2)/m(2) to 1.2 ± 0.3 cm(2)/m(2); P = .001). The mean mitral gradients significantly increased from rest to exercise, in both groups, but to a greater extent in the RMA group (change from 4.4 ± 1.4 to 11 ± 3.6 mm Hg; MVR: change from 4.3 ± 1.8 to 9 ± 3.5 mm Hg; P = .006). On multivariate analysis, MVR and exercise indexed effective orifice area were the main independent determinants of postoperative 6-MWT. In the RMA group, 25 patients experienced late mitral regurgitation recurrence, severe in 9 (14%) of them. The rate of postoperative cardiovascular events was significantly higher in the RMA group (21% vs MVR: 8%; P = .03). Follow-up survival was 83% in the RMA group and 88% in the MVR group (P = .54).

CONCLUSIONS

For chronic ischemic mitral regurgitation, MVR versus RMA was associated with better postoperative exercise hemodynamic performance and long-term functional capacity.

Moderate mitral regurgitation at the time of coronary bypass surgery: repair or leave it?

PURPOSE OF REVIEW

Moderate ischemic mitral regurgitation (IMR) is a common finding in patients undergoing coronary artery bypass grafting (CABG). In this review, we summarize the current evidence on the optimal management of this condition.

RECENT FINDINGS

In recent years, several randomized clinical trials have assessed the impact of concomitant restrictive mitral annuloplasty at the time of CABG on reverse left ventricular remodeling, IMR reduction and clinical outcomes.

SUMMARY

Surgical revascularization alone is a conservative strategy that reduces IMR in a significant proportion of patients. Concomitant restrictive annuloplasty provides better relief of mitral regurgitation in the immediate postoperative period, at the cost of increased perioperative morbidity. The only major randomized trial on the issue of moderate IMR published to date showed no difference in reverse left ventricular remodeling at 1 year between these two approaches. There are insufficient data in the literature to support the routine addition of mitral valve repair to CABG in patients with moderate IMR.

Therapeutic decision-making for patients with fluctuating mitral regurgitation

Mitral regurgitation (MR) is a common, progressive, and difficult-to-manage disease. MR is dynamic in nature, with physiological fluctuations occurring in response to various stimuli such as exercise and ischaemia, which can precipitate the development of symptoms and subsequent cardiac events. In both chronic primary and secondary MR, the dynamic behaviour of MR can be reliably examined during stress echocardiography. Dynamic fluctuation of MR can also have prognostic value; patients with a marked increase in regurgitant volume or who exhibit increased systolic pulmonary artery pressure during exercise have lower symptom-free survival than those who do not experience significant changes in MR and systolic pulmonary artery pressure during exercise. Identifying patients who have dynamic MR, and understanding the mechanisms underlying the condition, can potentially influence revascularization strategies (such as the surgical restoration of coronary blood flow) and interventional treatment (including cardiac resynchronization therapy and new approaches targeted to the mitral valve).

Novel Echocardiographic Indices as Predictors of Immediate Recurrence after Undersized Ring Annuloplasty for Ischemic Mitral Regurgitation

BACKGROUND AND AIM

Ischemic mitral regurgitation (IMR) is among the most serious complications of myocardial infarction which doubles the late mortality; mainly treated by undersizing ring annuloplasty. To find some preoperative echocardiographic indices that predict immediate failure of mitral valve annuloplasty (MVA), we designed the present study with more focusing on some novel parameters.

METHOD

Transthoracic echocardiography (TTE) indices of consecutive patients referred with 3+ or 4+ IMR were registered 24 hours before surgery. Thirty days later, a second TTE was performed. According to the results, the patients were categorized as the "successful" group (with 1+ or less mitral regurgitation) and the "unsuccessful" group (with 2+ or higher MR). Preoperative TTE indices were compared among the two groups using suitable statistical tests.

RESULTS

Of the total of 126 cases, 68 had successful and 58 had unsuccessful MVA. Statistically significant differences were found between the two groups for left ventricular ejection fraction (LVEF) (P = 0.007), left ventricular end systolic volume (LVESV) (P = 0.044), and basal-interpapillary muscle distance (IPMD) diastolic-to-systolic ratio (DSR) (P = 0.008). Receiver Operating Characteristic analysis demonstrated 37.5%, 3.85 cm(3) , and 1.25, as the best cutoff points for LVEF (P = 0.03, sensitivity: 81%, specificity: 69%), LVESV (P = 0.023, sensitivity: 83%, specificity: 57%), and basal-IPMD DSR (P = 0.001, sensitivity: 100%, specificity: 95%), respectively.

CONCLUSION

Among all TTE indices, LVEF, LVESV, and basal-IPMD DSR were helpful to differentiate between the successful and unsuccessful MVA results. We believe the basal-IPMD DSR as a novel index could be targeted in the future studies.

Influence of procedural differences on mitral valve configuration after surgical repair for functional mitral regurgitation: in which direction should the papillary muscle be relocated?

Background

After restrictive mitral annuloplasty (RMAP) for functional mitral regurgitation (MR), the MR frequently recurs. Papillary muscle relocation (PMR) should reduce the recurrence rate. We assessed the influence of procedural differences in PMR on the postoperative mitral valve configuration.

Methods

Thirty-nine patients who underwent mitral valve repair for functional MR were enrolled. In limited tethering cases, RMAP alone was performed (RMAP group; n = 23). In severe tethering cases, in addition to RMAP, bilateral papillary muscles were relocated in the direction of the posterior annulus (posterior PMR group; n = 10) or anterior annulus (anterior PMR group; n = 6). We performed pre- and postoperative transthoracic echocardiographic studies, introducing a new index, mitral inflow angle (MIA), to assess the diastolic mitral leaflet excursion. MIA was measured as the angle between the mitral annular plane and the bisector of the anterior and posterior leaflets.

Results

Postoperative MR grade was significantly reduced in each group (P < 0.001). Follow-up echocardiography showed recurrent MR in 13% of the patients in RMAP group. In contrast, no recurrent MR was observed in either the anterior PMR or the posterior PMR group. After surgery, MIA was significantly reduced in both the RMAP group (P < 0.01) and the posterior PMR group (P < 0.001), but was preserved in the anterior PMR group (NS). None of the postoperative variables showed any significant difference between the early and late postoperative phases.

Conclusions

In the surgical treatment of functional MR, a PMR procedure in addition to RMAP was effective in reducing systolic MR. However, mitral valve opening assessed by MIA was restricted even after RMAP alone. The restriction was severely augmented after additional posterior PMR, but was attenuated after additional anterior PMR. The papillary muscle should be relocated in the direction of the anterior annulus to preserve the diastolic opening of the mitral valve.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-014-0185-6) contains supplementary material, which is available to authorized users.

Predicting recurrent mitral regurgitation after mitral valve repair for severe ischemic mitral regurgitation

OBJECTIVES

The Cardiothoracic Surgical Trials Network recently reported no difference in the primary end point of left ventricular end-systolic volume index at 1 year postsurgery in patients randomized to repair (n = 126) or replacement (n = 125) for severe ischemic mitral regurgitation. However, patients undergoing repair experienced significantly more recurrent mitral regurgitation than patients undergoing replacement (32.6% vs 2.3%). We examined whether baseline echocardiographic and clinical characteristics could identify those who will develop moderate/severe recurrent mitral regurgitation or die.

METHODS

Our analysis includes 116 patients who were randomized to and received mitral valve repair. Logistic regression was used to estimate a model-based probability of recurrence or death from baseline factors. Receiver operating characteristic curves were constructed from these estimated probabilities to determine classification cut-points maximizing accuracy of prediction based on sensitivity and specificity.

RESULTS

Of the 116 patients, 6 received a replacement before leaving the operating room; all other patients had mild or less mitral regurgitation on intraoperative echocardiogram after repair. During the 2-year follow-up period, 76 patients developed moderate/severe mitral regurgitation or died (53 mitral regurgitation recurrences, 13 mitral regurgitation recurrences and death, and 10 deaths). The mechanism for recurrent mitral regurgitation was largely mitral valve leaflet tethering. Our model (including age, body mass index, sex, race, effective regurgitant orifice area, basal aneurysm/dyskinesis, New York Heart Association class, history of coronary artery bypass grafting, percutaneous coronary intervention, or ventricular arrhythmias) yielded an area under the receiver operating characteristic curve of 0.82.

CONCLUSIONS

The model demonstrated good discrimination in identifying patients who will survive 2 years without recurrent mitral regurgitation after mitral valve repair. Although our results require validation, they offer a clinically relevant risk score for selection of surgical candidates for this procedure.

Posterior papillary muscle anchoring affects remote myofiber stress and pump function: finite element analysis

BACKGROUND

The role of posterior papillary muscle anchoring (PPMA) in the management of chronic ischemic mitral regurgitation (CIMR) is controversial. We studied the effect of anchoring point direction and relocation displacement on left ventricular (LV) regional myofiber stress and pump function.

METHODS

Previously described finite element models of sheep 16 weeks after posterolateral myocardial infarction (MI) were used. True-sized mitral annuloplasty (MA) ring insertion plus different PPM anchoring techniques were simulated. Anchoring points tested included both commissures and the central anterior mitral annulus; relocation displacement varied from 10% to 40% of baseline diastolic distance from the PPM to the anchor points on the annulus. For each reconstruction scenario, myofiber stress in the MI, border zone, and remote myocardium as well as pump function were calculated.

RESULTS

PPMA caused reductions in myofiber stress at end-diastole and end-systole in all regions of the left ventricle that were proportional to the relocation displacement. Although stress reduction was greatest in the MI region, it also occurred in the remote region. The maximum 40% displacement caused a slight reduction in LV pump function. However, with the correction of regurgitation by MA plus PPMA, there was an overall increase in forward stroke volume. Finally, anchoring point direction had no effect on myofiber stress or pump function.

CONCLUSIONS

PPMA reduces remote myofiber stress, which is proportional to the absolute distance of relocation and independent of anchoring point. Aggressive use of PPMA techniques to reduce remote myofiber stress may accelerate reverse LV remodeling without impairing LV function.

Benefits of submitral procedures for ischemic mitral regurgitation

The surgical strategy for ischemic mitral regurgitation (MR) remains controversial. Ischemic MR is a secondary valve disease caused by left ventricular (LV) remodeling and subsequent papillary muscle displacement, usually without structural valve lesions. Reduction annuloplasty is the standard surgical procedure for this condition, though it cannot clearly provide a survival benefit for those with LV dysfunction and is associated with a high prevalence of late recurrence of MR. The valvular procedure alone could be insufficient to treat ischemic MR in terms of long-term survival and the prevention of recurrence because ischemic MR is primarily a ventricular disorder. Thus, recent studies have focused on alternative procedures that target the primary cause of ischemic MR, the papillary muscles and left ventricle. We believe that the appropriate selection of surgical procedures among valvular, subvalvular, and even ventricular ones, considering the severity of LV remodeling for each patient would be more beneficial. Here we review recent studies featuring various surgical approaches to ischemic MR, especially with submitral procedures.

Ischemic mitral regurgitation: current trends and treatment

PURPOSE OF REVIEW

Ischemic mitral regurgitation (MR) is a common finding in patients with coronary artery disease. In this review, we summarize the current literature describing the treatment of ischemic mitral regurgitation.

RECENT FINDINGS

Recent publications have focused on describing outcomes following the treatment of ischemic mitral regurgitation based on the specific mechanism of regurgitation. New therapies such as remodeling rings and percutaneous approaches, along with insights into mitral valve replacement, have advanced the treatment of ischemic mitral regurgitation.

SUMMARY

Mitral valve surgery and concomitant coronary artery bypass grafting represent the most effective strategy for the treatment of severe symptomatic ischemic mitral regurgitation. Overall, the survival of patients with ischemic mitral regurgitation is poor. Advances in mitral valve repair may improve long-term durability of surgery, whereas evolving percutaneous therapies may be a treatment option for patients with functional mitral regurgitation who are not surgical candidates.

Mitral valve repair versus replacement in patients with ischaemic mitral regurgitation and depressed ejection fraction: risk factors for early and mid-term mortality†

OBJECTIVES

Mitral valve (MV) surgery for ischaemic mitral regurgitation (IMR) in patients with depressed left ventricular ejection fraction (LVEF) is associated with poor outcomes. The optimal surgical strategy for IMR in these patients remains controversial. The objective of this study was to compare the early mortality and mid-term survival of MV repair versus MV replacement in patients with IMR and depressed LVEF undergoing coronary artery bypass grafting (CABG).

METHODS

A retrospective, observational, cohort study was undertaken of prospectively collected data on 126 consecutive CABG patients with IMR and LVEF <40% undergoing either MV repair (n = 98, 78%) or MV replacement (n = 28, 22%) between July 2002 and February 2011.

RESULTS

The overall mortality rate was 7.9% (n = 10). MV replacement was associated with a 4-fold increase in the risk of death compared with MV repair [17.9%, n = 5 vs 5.1%, n = 5; odds ratio (OR) 4.04, 95% confidence interval (CI) 1.08-15.1, P = 0.04]. However, after adjusting for preoperative risk factors, the type of surgical procedure was not an independent risk factor for early mortality (OR 0.1, 95% CI 0.01-31, P = 0.7). Multivariable analysis showed that preoperative LVEF (OR 0.8, 95% CI 0.6-0.9, P = 0.018), preoperative B-type natriuretic peptide (BNP) levels (OR 1.01, 95% CI 1-1.02, P = 0.025), preoperative left ventricle end-systolic diameter (OR 0.8, 95% CI 0.7-1.0, P = 0.05) and preoperative left atrial diameter (OR 1.3, 95% CI 1.0-1.6, P = 0.015) were independent risk factors of early mortality. At the median follow-up of 45 months (interquartile range 20-68 months), the mid-term survival rate was 74% in the MV repair group and 70% in the MV replacement group (P = 0.08). At follow-up, predictors of worse survival were BNP levels [hazard ratio (HR) 1.0, 95% CI 1.0-1.01, P = 0.047], preoperative renal failure (HR 4.6, 95% CI 1.1-20.3, P = 0.039) and preoperative atrial fibrillation (HR 3.3, 95% CI 1.1-10, P = 0.032).

CONCLUSIONS

MV repair in CABG patients with IMR and depressed LVEF is not superior to MV replacement with regard to operative early mortality and mid-term survival.

3-dimensional echocardiography and its role in preoperative mitral valve evaluation

Echocardiography plays a key role in the preoperative evaluation of mitral valve disease. 3-dimensional echocardiography is a relatively new development that is being used more and more frequently in the evaluation of these patients. This article reviews the available literature comparing the use of this new technology to classic techniques in the assessment of mitral valve pathology. The authors also review some of the novel insights learned from 3-dimensional echocardiography and how they may be used in surgical decision making and planning.

Ischemic mitral regurgitation: mechanisms, intraoperative echocardiographic evaluation, and surgical considerations

Ischemic mitral regurgitation (IMR) is a subcategory of functional rather than organic, mitral valve (MV) disease. Whether reversible or permanent, left ventricular remodeling creates IMR that is complex and multifactorial. A comprehensive TEE examination in patients with IMR may have important implications for perioperative clinical decision making. Several TEE measures predictive of MV repair failure have been identified. Current practice among most surgeons is to typically repair the MV in patients with IMR. MV replacement is usually reserved for situations in which the valve cannot be reasonably repaired, or repair is unlikely to be tolerated clinically.