Is repair preferable to replacement for ischemic mitral regurgitation?

Functional Mitral Valve Regurgitation: Mitral Valve Repair or Replacement? Our "Road Map" for the Appropriate Strategy

Objectives: The optimal surgical approach for the treatment of functional mitral regurgitation (FMR) remains controversial. Current guidelines suggest that the surgical approach has to be tailored to the individual patient. The aim of the present study was to clarify further aspects of this tailored treatment. Methods: From 01/2006 to 12/2015, 390 patients underwent mitral valve (MV) surgery for FMR (ischemic n = 241, non-ischemic n = 149) at our institution. A regression analysis was used to determine the effect of MV repair or replacement on survival. The patients were analyzed according to the etiology of the MR (ischemic or non-ischemic), different age groups (<65 years, 65-75 years, and >75 years), LV function, and LV dimensions, as well as the underlying heart rhythm. Results: The overall survival rates for the repair group at 1, 5, and 8 years were 86.1 ± 1.9%, 70.6 ± 2.6%, and 55.1 ± 3.1%, respectively. For the same intervals, the survival rates in patients who underwent MV replacement were 75.9 ± 4.5%, 58.6 ± 5.4%, and 40.9 ± 6.4%, respectively (p = 0.003). Patients younger than 65 years, with an ischemic etiology of FMR, poor ejection fraction (<30%), severe dilatation of left ventricle (LVEDD > 60mm), and presence of atrial fibrillation had significantly higher mortality rates after MV replacement (HR, 3.0; CI, 1.3-6.9; p = 0.007). Patients between 65 and 75 years of age had a higher risk of death when undergoing mitral valve replacement (HR, 1.7; CI, 1.0-2.8; p = 0.04). In patients older than 75 years, the surgical approach (MV repair or replacement) had no effect on postoperative survival (HR, 0.8; CI, 0.4-1.3; p = 0.003). Conclusions: Our data demonstrate that, in patients younger than 65 years, the treatment of choice for FMR should be MV repair. This advantage was even more evident in patients with an ischemic origin of MR, a poor ejection fraction, a severe LV dilatation, and atrial fibrillation.

Edge-to-edge with partial band mitral valve repair compared to replacement and undersized restrictive annuloplasty for ischemic mitral regurgitation

Objective

Evidence supports replacement over repair for ischemic mitral regurgitation due to improved durability; however, the latter often involves an undersized ring annuloplasty that does not include edge-to-edge approximation. The objective of this study was to evaluate the outcomes of replacement, edge-to-edge leaflet approximation with mild-undersized annuloplasty and undersized ring annuloplasty for ischemic mitral regurgitation.

Methods

This is a single-center retrospective study of patients undergoing mitral surgery for moderate-severe or greater ischemic mitral regurgitation, between 2004 and 2020, with mild-undersized annuloplasty, mitral valve replacement, or undersized restrictive annuloplasty (undersized ring annuloplasty). The primary outcome was all-cause mortality. Secondary outcomes included first recurrence of mitral regurgitation, heart failure hospitalization, and composite of valve-related events (bleeding, thromboembolism, endocarditis, and mitral valve reoperation).

Results

There were 121, 93, and 78 patients in the mitral valve replacement, mild-undersized annuloplasty, and undersized restrictive annuloplasty groups, respectively, with a median follow-up of 3.1, 5.9, and 3.8 years, respectively. Both mitral valve replacement (hazard ratio, 1.87; 95% CI, 1.029-3.415) and undersized restrictive annuloplasty (hazard ratio, 2.73; 95% CI, 1.480-5.061) were associated with worse survival compared with mild-undersized annuloplasty. At 2 years, the rate of mild-moderate mitral regurgitation was greater in the mild-undersized annuloplasty group compared with the mitral valve replacement group (P = .001) but less than in the undersized restrictive annuloplasty group (P = .001). The rate of recurrent moderate or greater mitral regurgitation at 2 years was similar between mild-undersized annuloplasty and mitral valve replacement groups but significantly higher after undersized restrictive annuloplasty (P < .0001). Mitral valve replacement and undersized restrictive annuloplasty were associated with a significant increase in the incidence of first heart failure hospitalization compared with mild-undersized annuloplasty (P < .001 and P = .001, respectively). Mitral valve replacement was associated with an increased incidence of valve-related events compared with mild-undersized annuloplasty (P = .002).

Conclusions

Surgical edge-to-edge approximation in addition to a mild-undersizing annuloplasty offers similar durability compared with replacement, with a lower rate of hospitalization for heart failure, and may confer a survival advantage.

Does Sustained Reduction of Functional Mitral Regurgitation Impact Survival?

Functional mitral regurgitation (FMR) is associated with increased mortality and has been considered a marker for advanced heart disease, yet the value of mitral valve repair (MVr) in this population remains unclear. This study aims to evaluate the impact of reducing FMR burden through surgical MVr on survival. Patients with severe FMR who underwent MVr with an undersized, complete, rigid, annuloplasty between 2004 and 2017 were assessed (n = 201). Patients were categorized based on grade of recurrent FMR (0-4). Time-to-event Kaplan-Meier estimations of freedom from death or reoperation were performed using the log-rank test. Cox proportional hazards models evaluated all-cause mortality and reported in hazards ratios (HR) and 95% confidence intervals (CI). Patients were categorized by postoperative recurrent FMR: 45% (91/201) of patients had grade 0, 29% (58/201) grade 1, 20% (40/201) grade 2, 2% (4/201) grade 3%, and 4% (8/201) grade 4. The cumulative incidence of reoperation with death as a competing risk was higher in patients with grades ≥3 recurrent FMR compared to grades ≤2 (44.6% vs 14.6%, subhazard ratio 3.69 [95% CI, 1.17-11.6]; P = 0.026). Overall freedom from death or reoperation was superior for recurrent FMR grades ≤2 compared to grades ≥3 (log-rank P < 0.001). Increasing recurrent FMR grade was independently associated with mortality (HR 1.30 [95% CI, 1.07-1.59] P = 0.009). Reduced postoperative FMR grade resulted in an incrementally lower risk of death or reoperation after MVr. These results suggest that achieving a durable reduction in FMR burden improves long-term survival.

A Computational Pipeline for Patient-Specific Prediction of the Postoperative Mitral Valve Functional State

While mitral valve (MV) repair remains the preferred clinical option for mitral regurgitation (MR) treatment, long-term outcomes remain suboptimal and difficult to predict. Furthermore, pre-operative optimization is complicated by the heterogeneity of MR presentations and the multiplicity of potential repair configurations. In the present work, we established a patient-specific MV computational pipeline based strictly on standard-of-care pre-operative imaging data to quantitatively predict the post-repair MV functional state. First, we established human mitral valve chordae tendinae (MVCT) geometric characteristics obtained from five CT-imaged excised human hearts. From these data, we developed a finite-element model of the full patient-specific MV apparatus that included MVCT papillary muscle origins obtained from both the in vitro study and the pre-operative three-dimensional echocardiography images. To functionally tune the patient-specific MV mechanical behavior, we simulated pre-operative MV closure and iteratively updated the leaflet and MVCT prestrains to minimize the mismatch between the simulated and target end-systolic geometries. Using the resultant fully calibrated MV model, we simulated undersized ring annuloplasty (URA) by defining the annular geometry directly from the ring geometry. In three human cases, the postoperative geometries were predicted to 1 mm of the target, and the MV leaflet strain fields demonstrated close agreement with noninvasive strain estimation technique targets. Interestingly, our model predicted increased posterior leaflet tethering after URA in two recurrent patients, which is the likely driver of long-term MV repair failure. In summary, the present pipeline was able to predict postoperative outcomes from pre-operative clinical data alone. This approach can thus lay the foundation for optimal tailored surgical planning for more durable repair, as well as development of mitral valve digital twins.

Outcome of Surgery for Ischemic Mitral Regurgitation Depends on the Type and Timing of the Coronary Revascularization

OBJECTIVE

Long-term outcomes of mitral valve (MV) repair versus MV replacement for ischemic mitral regurgitation (IMR) in patients undergoing either prior (PCR) or concomitant coronary revascularization (CCR) by surgery (CABG) or intervention (PCI) are uncertain.

METHODS AND RESULTS

Of 446 patients receiving MV surgery for IMR between July 2006 and December 2010, 125 patients-87 CCR (69.1%) and 38 PCR (30.9%)-were eligible for inclusion in the study. Survival was higher in CCR versus PCR at long-term follow-up (78.83% vs. 57.9%, p = 0.016). The incidence of MACCE was lower in the CCR compared to PCR at both hospital discharge (34.11% vs. 63.57%, p = 0.003) and at follow-up (34.11% vs. 65.79%, p = 0.0008). Patients receiving CABG or CABG with PCI in PCR had higher mortality risks after MV surgery than CCR patients (X² = 6.029, p = 0.014 and X² = 6.466, p = 0.011, respectively). Whereas in the PCR group, MV repair and MV replacement achieved similar survival probability (X² = 1.551, p = 0.213), MV repair in the CCR group led to improved survival compared to MV replacement (X² = 3.921, p = 0.048). In MV replacement, LAD-CABG improved survival compared to LAD-PCI (U = 15,000.00, Z = -2.373 p = 0.018), and a substantial impact of arterial IMA-LAD grafting was revealed in the Cox-regression analysis (HR 0.334, CI: 0.113-0.989, p = 0.048) as opposed to venous-LAD grafting (HR 0.588, CI: 0.166-2.078, p = 0.410).

CONCLUSION

Early treatment of IMR concomitant to coronary revascularization enhances long-term survival compared to delayed MV surgery after PCR. MV repair is not superior to MV replacement when performed late after coronary revascularization; however, MV repair leads to better survival than MV replacement when performed concomitantly with CABG with arterial LAD revascularization.

Fully Automated 3D Segmentation and Diffeomorphic Medial Modeling of the Left Ventricle Mitral Valve Complex in Ischemic Mitral Regurgitation

There is an urgent unmet need to develop a fully-automated image-based left ventricle mitral valve analysis tool to support surgical decision making for ischemic mitral regurgitation patients. This requires an automated tool for segmentation and modeling of the left ventricle and mitral valve from immediate pre-operative 3D transesophageal echocardiography. Previous works have presented methods for semi-automatically segmenting and modeling the mitral valve, but do not include the left ventricle and do not avoid self-intersection of the mitral valve leaflets during shape modeling. In this study, we develop and validate a fully automated algorithm for segmentation and shape modeling of the left ventricular mitral valve complex from pre-operative 3D transesophageal echocardiography. We performed a 3-fold nested cross validation study on two datasets from separate institutions to evaluate automated segmentations generated by nnU-net with the expert manual segmentation which yielded average overall Dice scores of 0.82±0.03 (set A), 0.87±0.08 (set B) respectively. A deformable medial template was subsequently fitted to the segmentation to generate shape models. Comparison of shape models to the manual and automatically generated segmentations resulted in an average Dice score of 0.93-0.94 and 0.75-0.81 for the left ventricle and mitral valve, respectively. This is a substantial step towards automatically analyzing the left ventricle mitral valve complex in the operating room.

Mitral valve repair in papillary muscle rupture

Papillary muscle rupture (PMR) is a significant mechanical complication following myocardial infarction (MI), a condition associated with a high mortality. It results in severe mitral valve regurgitation (MR), often accompanied by cardiogenic shock and pulmonary edema, requiring both emergent medical treatment and surgical intervention. Surgical treatment includes either chordal sparing mitral valve replacement or mitral valve repair, which is associated with a high mortality. Mitral valve repair is believed to be superior to mitral valve replacement with respect to improving left ventricular function, albeit with risk of repair failure and resulting in increased cross clamp times. Concomitant coronary revascularization may improve both short- and long-term outcomes after surgery. With advances in medical innovations in the field of transcatheter devices, these devices may serve as a bridge to recovery or treatment in the setting of acute MR due to PMR. However, long-term data will be required to establish the non-inferiority of one treatment modality over the other. Management of these patients should be guided by a dedicated mitral heart team.

Trends in Ischemic Mitral Regurgitation Following ST-Elevation Myocardial Infarction Over a 20-Year Period

Background: Ischemic mitral regurgitation (IMR) is a common complication of acute ST-elevation myocardial infarction (STEMI). Little is known regarding the impact of IMR over a long period of follow up.

Methods: Of 3,208 consecutive STEMI patients from a prospective registry, full echocardiographic information was available for 2,985 patients between the years 2000 and 2020. We compared the two decades- 2001 to 2010 and 2011 to 2020, and assessed for the presence of IMR at baseline, 3 (range 2–6) months and 12 (range 10–14) months after the index event.

Results: One thousand six hundred and sixty six patients were included in the first decade, 1,319 in the second. Mean patient age was 61.3 ± 12.3 years, 21.1% female patients in the first decade vs. 60.9 ± 12.0 years and 22.2% female in the second (p = 0.40 and p = 0.212, respectively). Rates of moderate IMR or above during the index admission were 17.2% in the first period and 9.3% in the second one (p < 0.001). After 3 months, the rate of IMR was 48.5% for those who suffered from IMR at baseline, vs. 9.5% for those without IMR at baseline (HR- 4.2, p < 0.001). Death rates for those with moderate IMR or above were 14.7% and 17.8% after 1 and 2 years, respectively, vs. 7.3 and 9.6% for those without (p < 0.001 for both). IMR was associated with 1 year mortality in multivariate analysis (HR-1.37; 1.09–2.20, p = 0.009), as well as in propensity score matched analysis (HR 1.29; CI: 1.07–1.91; p < 0.001).

Conclusions: IMR is a common complication following acute STEMI, impacting prognosis. Rates of IMR have declined significantly over the years.

Mitral Annular Forces and Their Potential Impact on Annuloplasty Ring Selection

Objectives: To provide an overview that describes the characteristics of a mitral annuloplasty device when treating patients with a specific type of mitral regurgitation according to Carpentier's classification of mitral regurgitation.

Methods: Starting with the key search term “mitral valve annuloplasty,” a literature search was performed utilising PubMed, Google Scholar, and Web of Science to identify relevant studies. A systematic approach was used to assess all publications.

Results: Mitral annuloplasty rings are traditionally categorised by their mechanical compliance in rigid-, semi-rigid-, and flexible rings. There is a direct correlation between remodelling capabilities and rigidity. Thus, a rigid annuloplasty ring will have the highest remodelling capability, while a flexible ring will have the lowest. Rigid- and semi-rigid rings can furthermore be divided into flat and saddled-shaped rings. Saddle-shaped rings are generally preferred over flat rings since they decrease annular and leaflet stress accumulation and provide superior leaflet coaptation. Finally, mitral annuloplasty rings can either be complete or partial.

Conclusions: A downsized rigid- or semi-rigid ring is advantageous when higher remodelling capabilities are required to correct dilation of the mitral annulus, as seen in type I, type IIIa, and type IIIb mitral regurgitation. In type II mitral regurgitation, a normosized flexible ring might be sufficient and allow for a more physiological repair since there is no annular dilatation, which diminishes the need for remodelling capabilities. However, mitral annuloplasty ring selection should always be based on the specific morphology in each patient.

Transcatheter Mitral Valve Implantation: Current Status and Future Perspectives

Mitral transcatheter therapies represent the treatment of choice for all patients deemed unsuitable for cardiac surgery. So far, the largest clinical experience has been limited to percutaneous repair techniques. However, given the complexity and heterogeneity of mitral valve anatomy and pathology, transcatheter mitral valve implantation will widen the mitral valve therapies horizon, toward a patient-tailored approach. Current data about transcatheter mitral valve implantation is still limited and, although some data are promising, there are still some issues to be addressed. This review provides a comprehensive insight into the available devices and describes potential advantages and limitations of transcatheter mitral valve implantation.

Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

New stent for transapical mitral valve replacement in acute swine experiment

Background

Many patients with mitral regurgitation are denied open-heart surgery due to perceived high risk. Transcatheter mitral valve replacement is a therapeutic alternative for patients at high surgical risk. This study aimed to assess the feasibility of a new self-expanding valved stent for transcatheter mitral valve replacement via apex in an acute animal model.

Methods

Eight porcine experiments were performed in the acute study. A left thoracotomy was performed, and the new self-expanding transcatheter valved stent was deployed under fluoroscopic guidance in the native mitral annulus via apex. Hemodynamic data were recorded before and after implantation. Mitral annulus diameter and valve area were measured using echocardiography. Transvalvular and left ventricular outflow tract pressure gradients were measured using invasive methods.

Results

Seven animals underwent successful transapical mitral valve replacement; the implantation was unsuccessful in one animal. The mean procedure time, defined from placement to tightening of the purse-string suture, was 17.14 ± 7.86 min. Hemodynamic data before and after transapical mitral valve replacement showed no difference in statistical analysis. The mean diameter of the self-expanding device after implantation was 2.58 ± 1.04 cm; the mean functional area was 2.70 ± 0.26 cm². Trace-to-mild central and paravalvular leaks were detected in 7 valves. The mean pressure gradient across the self-expanding device was 2.00 ± 0.82 mmHg; the corresponding gradient across the LVOT was 3.28 ± 1.11 mmHg. Postmortem evaluation confirmed precise device positioning in 7 animals with no signs of LVOT obstruction.

Conclusion

Transcatheter mitral replacement of the new valved stent was confirmed feasible in acute preclinical models. The new stent reveals optimal design parameters.

Transcatheter mitral valve replacement: latest advances and future directions

Mitral regurgitation remains the most common form of valve disease worldwide and given an aging population with a significant proportion of secondary mitral regurgitation, a transcatheter approach to mitral valve replacement has become a major goal of the transcatheter therapeutics field. Mitral regurgitation can be caused by disease of the leaflets (primary) or by diseases of the left atrium or left ventricle (LV) (secondary or functional), and may involve overlap of the two (mixed disease). The location of the mitral valve (and large size), the approach to anchoring a valve replacement, and concerns about left ventricular outflow tract (LVOT) obstruction are all issues that have made the transcatheter delivery of a valve replacement challenging. Despite these challenges, both transapical and transseptal devices are currently being developed, with several in early feasibility trials and several entering pivotal trials. As the field of transcatheter mitral valve replacement (TMVR) improves and develops, a critical part of evaluating patients with mitral valve disease will be utilizing the heart team approach to identify and individualize the most appropriate treatment for each patient.

Mechanical testing of glutaraldehyde cross-linked mitral valves. Part two: Elastic and viscoelastic properties of chordae tendineae

The aim of this study was to assess whether the mechanical properties of mitral valve chordae tendineae are sensitive to being cross-linked under load. A total 64 chordae were extracted from eight porcine hearts. Two chordae (posterior basal) from each heart were subjected to uniaxial ramp testing and six chordae (two strut, two anterior basal and two posterior basal) were subjected to dynamic mechanical analysis over frequencies between 0.5 and 10 Hz. Chordae were either cross-linked in tension or cross-linked in the absence of loading. Chordae cross-linked under load transitioned from high to low extension at a lower strain than cross-linked unloaded chordae (0.07 cf. 0.22), with greater pre-transitional (30.8 MPa cf. 5.78 MPa) and post-transitional (139 MPa cf. 74.1 MPa) moduli. The mean storage modulus of anterior strut chordae ranged from 48 to 54 MPa for cross-linked unloaded chordae, as compared to 53-61 MPa cross-linked loaded chordae. The mean loss modulus of anterior strut chordae ranged from 2.3 to 2.9 MPa for cross-linked unloaded chordae, as compared to 3.8-4.8 MPa cross-linked loaded chordae. The elastic and viscoelastic properties of chordae following glutaraldehyde cross-linking are dependent on the inclusion/exclusion of loading during the cross-linking process; with loading increasing the magnitude of the material properties measured.

Transcatheter Mitral Valve Replacement: Rationale and Current Status

Mitral regurgitation (MR) is the most prevalent form of moderate or severe valve disease in the developed world. MR can result from impairment of any part of the mitral valve apparatus and is classified as primary (disease of the leaflets) or secondary (functional). The presence of at least moderate MR is associated with increased morbidity and mortality. With the goal of avoiding the risks of traditional surgery, transcatheter mitral valve therapies have been developed. The current transcatheter repair techniques are limited by therapeutic target and incomplete MR reduction, and thus transcatheter mitral valve replacement (TMVR) has been pursued. Several devices (both transapical and transseptal) are under development, with both early feasibility and pivotal trials under way. As this field develops, the decision to treat with TMVR will require a heart team approach that takes patient-, disease-, and device-specific factors into account.

Don't go breaking my heart valve: historical review of mitral valve replacement

Management of mitral valve disease in the western world continues to lag behind its aortic counterpart, particularly in the realm of percutaneous valve replacement. It is a more complex anatomical region, with varying disease states and unique pathophysiological and epidemiological characteristics that make it a distinct challenge to treat in modern medicine. Latest research and development, however, have provided new answers to the challenges associated with the mitral valve. In this review, the most common disease states afflicting the mitral valve are outlined, specific challenges associated with treatment are discussed, and both current and cutting-edge replacement devices are described. This review focuses on replacement and prosthetic devices, while acknowledging the role of valve repair. The future of mitral valve replacement remains to be seen, as new methodologies and prosthetic designs continue to present themselves as the best answer to the challenge.

Predictors of hospital mortality after surgery for ischemic mitral regurgitation: the Toronto General Hospital experience

BACKGROUND

The benefit of mitral valve repair (MVr) over replacement in patients with severe ischemic mitral regurgitation (IMR) is still controversial. We report our early postoperative outcomes of repair versus replacement.

METHODS

Data were collected for patients undergoing first-time mitral valve surgery for severe IMR between 1990 and 2009 (n = 393). Patients who underwent combined procedures for papillary muscle rupture, post-infarction ventricular septal defect, endocarditis, or any previous cardiac surgery were excluded. Preoperative demographics, operative variables, and hospital outcomes were analyzed, and multivariable regression analysis was employed to identify independent predictors of hospital mortality.

RESULTS

Valve repair was performed in 42% (n = 164) of patients and replacement in 58% (n = 229). Patients who underwent replacement were older and had a higher prevalence of unstable angina, New York Heart Association Class IV symptoms, preoperative cardiogenic shock, preoperative myocardial infarction, peripheral vascular disease, renal failure, and urgent or emergency surgery (all p < .05). Unadjusted hospital mortality was higher in patients undergoing valve replacement (13% vs. 5%; p = .01). Valve repair was associated with a lower prevalence of postoperative low cardiac output syndrome. Multivariable analysis revealed that age, urgency of operation, and preoperative left ventricular (LV) function were independent predictors of hospital mortality. Importantly, MVr versus replacement was not an independent predictor of hospital mortality.

CONCLUSION

Our data did not suggest an early survival benefit to MVr over replacement for IMR. However, age, LV dysfunction, and the need for urgent surgery were independently associated with hospital mortality.

DL-based segmentation of endoscopic scenes for mitral valve repair

Minimally invasive surgery is increasingly utilized for mitral valve repair and replacement. The intervention is performed with an endoscopic field of view on the arrested heart. Extracting the necessary information from the live endoscopic video stream is challenging due to the moving camera position, the high variability of defects, and occlusion of structures by instruments. During such minimally invasive interventions there is no time to segment regions of interest manually. We propose a real-time-capable deep-learning-based approach to detect and segment the relevant anatomical structures and instruments. For the universal deployment of the proposed solution, we evaluate them on pixel accuracy as well as distance measurements of the detected contours. The U-Net, Google’s DeepLab v3, and the Obelisk-Net models are cross-validated, with DeepLab showing superior results in pixel accuracy and distance measurements.

The most influential papers in mitral valve surgery; a bibliometric analysis

This study is an analysis of the 100 most cited articles in mitral valve surgery. A bibliometric analysis is a tool to evaluate research performance in a given field. It uses the number of times a publication is cited by others as a proxy marker of its impact. The most cited paper Carpentier et al. discusses mitral valve repair in terms of restoring the geometry of the entire valve rather than simply narrowing the annulus (Carpentier, J Thorac Cardiovasc Surg 86:23–37, 1983). The first successful mitral valve repair was performed by Elliot Cutler at Brigham and Women’s Hospital in 1923 (Cohn et al., Ann Cardiothorac Surg 4:315, 2015). More recently percutaneous and minimally invasive techniques that were originally designed as an option for high risk patients are being trialled in other patient groups (Hajar, Heart Views 19:160–3, 2018). Comparison of percutaneous method with open repair represents an expanding area of research (Hajar, Heart Views 19:160–3, 2018). This study will analyse the top 100 cited papers relevant to mitral valve surgery, identifying the most influential papers that guide current management, the institutions that produce them and the authors involved.

Intraoperative post-annuloplasty three-dimensional valve analysis does not predict recurrent ischemic mitral regurgitation

BACKGROUND

High ischemic mitral regurgitation (IMR) recurrence rates continue to plague IMR repair with undersized ring annuloplasty. We have previously shown that pre-repair three-dimensional echocardiography (3DE) analysis is highly predictive of IMR recurrence. The objective of this study was to determine the quantitative change in 3DE annular and leaflet tethering parameters immediately after repair and to determine if intraoperative post-repair 3DE parameters would be able to predict IMR recurrence 6 months after repair.

METHODS

Intraoperative pre- and post-repair transesophageal real-time 3DE was performed in 35 patients undergoing undersized ring annuloplasty for IMR. An advanced modeling algorhythm was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with transthoracic echocardiography 6 months after repair.

RESULTS

Annuloplasty significantly reduced septolateral diameter, commissural width, annular area, and tethering volume and significantly increased all segmental tethering angles (except A2). Intraoperative post-repair annular geometry and leaflet tethering did not differ significantly between patients with recurrent IMR (n = 9) and patients with non-recurrent IMR (n = 26). No intraoperative post-repair predictors of IMR recurrence could be identified.

CONCLUSIONS

Undersized ring annuloplasty changes mitral geometry acutely, exacerbates leaflet tethering, and generally fixes IMR acutely, but it does not always fix the delicate underlying chronic problem of continued left ventricular dilatation and remodeling. This may explain why pre-repair 3D valve geometry (which reflects chronic left ventricular remodeling) is highly predictive of recurrent IMR, whereas immediate post-repair 3D valve geometry (which does not completely reflect chronic left ventricular remodeling anymore) is not.

Operative Results of Mitral Valve Repair and Replacement in Chronic Ischaemic Mitral Valve Regurgitation

BACKGROUND

Ischaemic mitral regurgitation (IMR) carries significant morbidity and mortality. Surgical management includes coronary artery bypass surgery alone or concomitant with mitral valve repair or replacement. There is ongoing debate regarding the appropriate approach to the mitral valve in relation to long-term outcomes. This review examines our early and late follow-up, with operative and echocardiographic outcomes for mitral valve repair and mitral replacement for chronic IMR.

METHODS

A retrospective review was performed on prospectively collected data of 119 consecutive patients who either underwent mitral repair (n=101) or mitral replacement (n=18) for chronic IMR at Prince Henry and The Prince of Wales hospitals in Sydney between 1999-2016. All patients had pre and postoperative transthoracic echocardiograms. Follow-up echocardiographic data was obtained from the most recent clinical appointment. Follow-up mortality outcomes were obtained with ethics approval from the Australian National Death Index (NDI).

RESULTS

There was no statistical difference between cardiopulmonary bypass (CPB) time, cross-clamp time, time spent in intensive care unit (ICU) and time to discharge between cohorts. The replacement cohort was noted to have higher preoperative pulmonary artery (PA) pressures and a higher severity of IMR. Seven (7) deaths were in the mitral valve (MV) repair group within 30 days (6.9%) and three deaths in the MV replacement group within 30 days (16.7%). Echocardiographic follow-up was complete in 78% of the MV repair cohort at an average of 4.06±2.66 years, and 73% complete in the MV replacement cohort at an average of 6.09±4.3 years. Three (3) patients had prior MV repair before MV replacement early at days zero and 17, and late at 8 years respectively. Follow-up echocardiography showed mitral regurgitation (MR) in the mitral valve repair cohort as ≤ mild in 83.5% and ≤ trivial in 35.6%. In the MV replacement cohort MR ≤ mild in 100% and ≤ trivial in 82% with no moderate or severe MR. Preoperative tricuspid regurgitation (TR) and a flexible annuloplasty were predictive of an MR grade > mild in the repair cohort at discharge. Five-year (5-year) survival for the repair cohort was 85% with a mean follow-up time of 7.1±3.83 years. For the replacement cohort, five-year survival was 77.8% with a mean follow-up time of 5.35±1.54 years.

CONCLUSIONS

Mitral valve repair and replacement for chronic IMR has acceptable mortality, reintervention rates and excellent postoperative echocardiographic degrees of IMR in this cohort. Further evaluation is required into quality of life post intervention for IMR and of preoperative predictive factors of significant MR postoperatively to help guide the appropriate choice of treatment. The presence of preoperative tricuspid regurgitation of moderate grade or higher, and the use of a flexible annuloplasty may indicate patients more likely to have a higher grade of MR at follow-up following mitral valve repair in patients with IMR.

Transcatheter mitral repair and replacement: which procedure for which patient?

Given the complexity and the heterogeneity of mitral valve anatomy and pathology, different technologies and approaches (including repair and replacement methods) are potentially required to allow specific patient-tailored approaches, addressing each anatomy with the most appropriate device. Since we are still far from having an unbiased and evidence-supported process to select the best treatment for each patient, this review will provide an overview of the elements that should be taken into consideration when selecting the best procedure for each patient.

Surgical intervention for ischemic mitral regurgitation: how can we achieve better outcomes?

Ischemic mitral regurgitation (MR) is a common complication of myocardial infarction. Left ventricular (LV) dysfunction and distortion of the subvalvular apparatus are the main contributors to ischemic MR. Coronary artery bypass grafting alone, mitral valve replacement, and mitral valve repair, with or without subvalvular procedures, have been performed for moderate-to-severe ischemic MR. Several randomized studies on the surgical treatment of ischemic MR have been performed; however, the optimal surgical strategy remains controversial because none have demonstrated a clear survival benefit. Since the mechanisms of ischemic MR are complex and multifactorial, comprehensive preoperative assessment of LV function and geometry (both global and regional), mitral valve configuration, viability testing, and exercise echocardiography are needed. A better understanding of this complicated disease and of the advantages and limitations of each procedure may help us devise more effective patient-specific surgical treatment strategies and achieve better outcomes.

On the simulation of mitral valve function in health, disease, and treatment

The mitral valve (MV) is the heart valve that regulates blood ?ow between the left atrium and left ventricle (LV). In situations where the MV fails to fully cover the left atrioventricular ori?ce during systole, the resulting regurgitation causes pulmonary congestion, leading to heart failure and/or stroke. The causes of MV insuf?ciency can be either primary (e.g. myxomatous degeneration) where the valvular tissue is organically diseased, or secondary (typically inducded by ischemic cardiomyopathy) termed ischemic mitral regurgitation (IMR), is brought on by adverse LV remodeling. IMR is present in up to 40% of patients and more than doubles the probability of cardiovascular morbidity after 3.5 years. There is now agreement that adjunctive procedures are required to treat IMR caused by lea?et tethering. However, there is no consensus regarding the best procedure. Multicenter registries and randomized trials would be necessary to prove which procedure is superior. Given the number of proposed procedures and the complexity and duration of such studies, it is highly unlikely that IMR procedure optimization will be achieved by prospective clinical trials. There is thus an urgent need for cell and tissue physiologically based quantitative assessments of MV function to better design surgical solutions and associated therapies. Novel computational approaches directed towards optimized surgical repair procedures can substantially reduce the need for such trial-and-error approaches. We present the details of our MV modeling techniques, with an emphasis on what is known and investigated at various length scales.

Ischemic Mitral Regurgitation: Current Understanding and Surgical Options

Secondary, or functional, mitral regurgitation (MR) occurs with impaired coaptation of structurally normal valve leaflets due to abnormal structure and/or function of the left ventricle (LV). A leading cause of functional mitral regurgitation is ischemic cardiomyopathy, resulting in left ventricular dysfunction and subsequent congestive heart failure (CHF) and ischemic mitral regurgitation (IMR). The value of surgical or transcatheter correction of IMR remains controversial, since the underlying pathology of IMR is attributed to a dysfunctional left ventricle. However, even mild IMR has been shown to be harmful to CHF patients, as IMR is both a surrogate of advanced CHF and an independent contributor to CHF morbidity and mortality. While observational and randomized studies have examined surgical treatment of IMR with conflicting outcomes, additional well-designed randomized controlled trials should be performed to further clarify the optimal treatment for IMR. Additionally, close attention should be paid to the quality of interventions performed, as durable reduction in IMR provides the best hope of a positive clinical outcome. This review focuses on the pathophysiology of IMR, current evidence regarding surgical and transcatheter interventions, and future directions in management of IMR.

A Comparison of the Degree of Residual Mitral Regurgitation by Intraoperative Transoesophageal and Follow-up Transthoracic Echocardiography following Mitral Valvuloplasty

Patients who undergo mitral valve repair for mitral regurgitation and have mild residual mitral regurgitation may have an increased risk of re-operation in future years. Intraoperative transoesophageal echocardiography has now become a standard of practice for mitral valve repair surgery. We identified 106 patients who underwent attempted mitral valve repair over a three-year period in our institution. We retrospectively reviewed the grade of residual mitral regurgitation assigned following successful mitral valve repair (‘mild’ or less residual regurgitation) by intraoperative transoesophageal echocardiography and compared it to the observed grade of mitral regurgitation seen at follow-up transthoracic echocardiography. No patient had unexpected moderate or severe mitral regurgitation postoperatively, suggesting that intraoperative transoesophageal echocardiography performed in a medium-sized department is a sensitive tool for the early detection of failed mitral repair. Mild residual mitral regurgitation on intraoperative transoesophageal echocardiography was not reliably associated with mild mitral regurgitation on follow-up transthoracic echocardiography. In fact, 61% of patients with mild mitral regurgitation identified by intraoperative transoesophageal echocardiography had reduced mitral regurgitation at follow-up transthoracic echocardiography (to nil/trace residual mitral regurgitation). This observation, in conjunction with the limitations of the data supporting the goal of ‘echo perfect’ repair, suggests that a second attempt at repair should not be made based on the intraoperative transoesophageal echocardiography finding of mild residual mitral regurgitation alone.

Repair or replacement for severe ischemic mitral regurgitation: A meta-analysis

BACKGROUND

The best surgical option for severe ischemic mitral regurgitation (IMR) is still controversial. The aim of this study was to perform a meta-analysis to compare the clinical outcomes of mitral valve repair (MVP) with replacement (MVR).

METHODS

A literature search was conducted in PubMed, Embase, and Medline using the terms "ischemic mitral regurgitation" and "repair or annuloplasty or reconstruction" and "replacement" in the title/abstract field. The primary outcomes of interest were perioperative mortality and long-term survival. Secondary outcomes were mitral regurgitation (MR) recurrence and reoperation.

RESULTS

Of 276 studies, 13 studies met the inclusion and exclusion criteria. A total of 1993 patients were included in these studies, consisting of 1259 (63%) repair cases, and 734 (37%) replacement cases. Perioperative mortality was lower with MVP compared with MVR [OR 0.61; (95% CI, 0.43-0.87; P < .05)]. There was no difference with respect to long-term survival [HR 0.75; (95% CI, 0.52-1.09; P = .14)] and reoperation [OR 0.77; (95% CI, 0.38-1.57; P = .47)]. MVP is associated with a higher recurrence of MR [OR = 4.09; (95% CI, 1.82-9.19; P < .001)].

CONCLUSION

MVP is associated with a lower perioperative mortality but a higher recurrence of MR compared with MVR for severe IMR. No differences were found with respect to long-term survival and reoperation.

Effect of glutaraldehyde based cross-linking on the viscoelasticity of mitral valve basal chordae tendineae

BACKGROUND

Mitral valve failure can require repair or replacement. Replacement bioprosthetic valves are treated with glutaraldehyde prior to implantation. The aim of this study was to determine the changes in mechanical properties following glutaraldehyde fixation of mitral valve chordae.

METHODS

To investigate the impact of glutaraldehyde on mitral valve chordae, 24 basal chordae were dissected from four porcine hearts. Anterior and posterior basal (including strut) chordae were used. All 24 chordae were subjected to a sinusoidally varying load (mean level 2N, dynamic amplitude 2N) over a frequency range of 0.5-10 Hz before and after glutaraldehyde treatment.

RESULTS

The storage and loss modulus of all chordal types decreased following glutaraldehyde fixation. The storage modulus ranged from: 108 to 119 MPa before fixation and 67.3-87.4 MPa following fixation for basal chordae; 52.3-58.4 MPa before fixation and 47.9-53.5 MPa following fixation for strut chordae. Similarly, the loss modulus ranged from: 5.47 to 6.25 MPa before fixation and 3.63-4.94 MPa following fixation for basal chordae; 2.60-2.97 MPa before fixation and 2.31-2.93 MPa following fixation for strut chordae.

CONCLUSION

The viscoelastic properties of mitral valve chordae are affected by glutaraldehyde fixation; in particular, the reduction in storage moduli decreased with an increase in chordal diameter.

Systolic characteristics and dynamic changes of the mitral valve in different grades of ischemic mitral regurgitation - insights from 3D transesophageal echocardiography

BACKGROUND

Mitral regurgitation in ischemic heart disease (IMR) is a strong predictor of outcome but until now, pathophysiology is not sufficiently understood and treatment is not satisfying. We aimed to systematically evaluate structural and functional mitral valve leaflet and annular characteristics in patients with IMR to determine the differences in geometric and dynamic changes of the MV between significant and mild IMR.

METHODS

Thirty-seven patients with IMR (18 mild (m)MR, 19 significant (moderate+severe) (s)MR) and 33 controls underwent TEE. 3D volumes were analyzed using 3D feature-tracking software.

RESULTS

All IMR patients showed a loss of mitral annular motility and non-planarity, whereas mitral annulus dilation and leaflet enlargement occurred in sMR only. Active-posterior-leaflet-area decreased in early systole in all three groups accompanied by an increase in active-anterior-leaflet-area in early systole in controls and mMR but only in late systole in sMR.

CONCLUSIONS

In addition to a significant enlargement and loss in motility of the MV annulus, patients with significant IMR showed a spatio-temporal alteration of the mitral valve coaptation line due to a delayed increase in active-anterior-leaflet-area. This abnormality is likely to contribute to IMR severity and is worth the evaluation of becoming a parameter for clinical decision-making. Further, addressing the leaflets aiming to increase the active leaflet-area is a promising therapeutic approach for significant IMR. Additional studies with a larger sample size and post-operative assessment are warranted to further validate our findings and help understand the dynamics of the mitral valve.

Coronary computed tomography angiography detection of short- and long-term outcomes after heart valve surgery with high risk cardiovascular patients

Coronary computed tomography angiography (CCTA) is a promising alternative technique to detect significant coronary artery lesions in high-risk cardiovascular patients with left ventricular dysfunction (left ventricular ejection fractions < 40%) referred for elective valve surgery, while little research about the use of CCTA to detect the outcomes of heart valve surgery was performed. Forty-six consecutive high-risk cardiovascular patients with the New York Heart Association (NYHA) classification were retrospectively studied. Immediate, 10-week, 20-week, and 40-week outcomes after heart valve surgery were assessed with CCTA. Patients' average age at the time of surgery was 73 years, with the majority being male (54.35%). Among the CCTA parameters detected after 10, 20, and 40 weeks after heart valve surgery, only segment involvement score (SIS) did reach statistical significance when compared with baseline levels. The cumulative mortality rate at 10, 20, and 40 weeks were 19.56%, 30.43%, and 39.13% respectively. It can be seen that the early death is mainly due to complications, and with the time-lapse of surgery, the impact of complications on death is gradually eliminated. CCTA might be a useful tool to detect the outcomes of short- and long-term outcomes after heart valve surgery with high risk cardiovascular patients, and SIS level is associated with the short- and long-term outcomes.

Long-term outcomes of mitral valve annuloplasty versus subvalvular sparing replacement for severe ischemic mitral regurgitation

BACKGROUND

Although practice guidelines recommend surgery for patients with severe chronic ischemic mitral regurgitation (CIMR), they do not specify whether to repair or replace the mitral valve. The purpose of this study was to evaluate the long-term outcomes in patients with severe CIMR undergoing mitral valve annuloplasty (MVA) versus subvalvular sparing mitral valve replacement (MVR).

METHODS

392 consecutive patients who underwent MVA or subvalvular sparing MVR for treatment of severe CIMR were retrospectively reviewed.

RESULTS

After adjustment for baseline differences with multivariable regression analysis at 53 months follow-up (interquartile range, 34-81 months), there was no significant difference between the two groups for risk of major adverse cardiac or cerebrovascular events (MACCE), cardiac death, or all-cause death. Propensity score matching extracted 77 pairs. During the follow-up, compared with the MVR group, both the left atrium and left ventricle end-diastolic diameter were markedly larger (p = 0.013 and p = 0.033, respectively), and the incidence of mitral regurgitation recurrence was significantly higher in the MVA group (p < 0.001). No significant difference was observed between the two propensity score-matched groups in composite in-hospital outcomes, overall survival, freedom from cardiac death or MACCE, except subvalvular sparing MVR was associated with a lower incidence of hospitalization for heart failure than MVA (p = 0.015).

CONCLUSIONS

Subvalvular sparing MVR is a suitable management of patients with severe CIMR, it is more favorable to ventricular remodeling and is associated with a lower incidence of hospitalization for heart failure than MVA.

Surgical Treatment of Ischemic Mitral Regurgitation: Valve Repair Versus Replacement

PURPOSE OF REVIEW

Ischemic mitral regurgitation (MR), which occurs in about 20-30% patients with a prior myocardial infarction, is associated with worsening heart failure and an increase in cardiovascular mortality. It should be treated surgically if certain hemodynamic severity criteria are met and in patients who continue to experience symptoms of heart failure despite optimal medical therapy. However, current guidelines do not suggest which of the available approaches to mitral valve surgery-mitral valve (MV) repair or replacement (MVR) is superior for this indication. While MV repair is reported to confer improved survival, MVR may provide higher rates of freedom from recurrent MR. This article attempts to provide the reader with a comprehensive review and comparison of current techniques of mitral valve surgery in patients with severe ischemic MR.

RECENT FINDINGS

The first randomized trial to compare MV repair versus MVR in patients with severe ischemic MR, the Cardiothoracic Surgical Trials Network (CTSN) trial, was recently concluded and reported no significant difference in the primary outcome of left ventricular end systolic volume index between the two approaches at either 1- or 2-year follow-ups. Data comparing approaches of MV repair and MVR for ischemic MR is largely limited to small, non-randomized retrospective trials. The only randomized trial data to examine this issue suggested no difference in mortality with either MVR or MV repair; however, MVR was shown to be consistently associated with higher rates of MR recurrence. Certain echocardiographic features have been reported to predict poor outcomes with MVR and may help refine the selection of the surgical approach in the individual patient.

Ischemic mitral regurgitation

Ischemic mitral regurgitation (IMR) is a frequent complication of left ventricular (LV) global or regional pathological remodeling due to chronic coronary artery disease. It is not a valve disease but represents the valvular consequences of increased tethering forces and reduced closing forces. IMR is defined as mitral regurgitation caused by chronic changes of LV structure and function due to ischemic heart disease and it worsens the prognosis. In this review, we discuss on etiology, pathophysiology, and mechanisms of IMR, its classification, evaluation, and therapeutic corrective methods of IMR.

Mitral Valve Repair: The French Correction Versus the American Correction

Degenerative mitral valve disease causing mitral regurgitation is the most common organic valve pathology and is classified based on leaflet motion. The "French correction" mitral valve repair method restores normal valvular anatomy with extensive leaflet resection, chordal manipulation, and rigid annuloplasty. The American correction attempts to restore normal valve function through minimal leaflet resection, flexible annuloplasty, and use of artificial chordae. These differing methods of mitral valve repair reflect an evolution in principles, but both require understanding of the valve pathology and correction of leaflet prolapse and annular dilatation. Adhering to those unifying principles and ensuring that no patient leaves the operating room with significant persistent mitral regurgitation produces durable results and satisfactory patient outcomes.

[Impact of mitral annuloplasty combined with surgical revascularization in ischemic mitral regurgitation]

INTRODUCTION

Ischemic Mitral Regurgitation (IMR) is a serious complication of coronary artery disease and is associated with a poor prognosis. The optimal surgical treatment of IMR involves controversies in its indications and modalities.

OBJECTIVES

To determine whether mitral annuloplasty associated with surgical revascularization improved short and mid terms outcomes compared with revascularization alone in patients with IMR.

METHODS

Between January 2007 and January 2011, 81 patients operated on Department of Cardiovascular Surgery "B" were included in this study divided into 3 groups. Group 1: 28 patients with IMR had mitral valve surgery associated with surgical revascularization. Group 2: 26 patients with IMR had surgical revascularization without mitral valve surgery. Group 3: 27 patients without IMR had isolated revascularization. Clinical end-points were operative mortality, late mortality, postoperative functional status (NYHA), and the Effective Regurgitant Orifice (ERO) at last follow-up. The mean follow-up was 5 years for groups 1 and 2 and 4 years for group 3.

RESULTS

There was no difference between the 3 groups regarding age, sex, cardiovascular risk factors, and extension of coronary artery disease. The Left Ventricle End Diastolic Diameter (LVEDD) and the Left Ventricle Ejection Fraction (LVEF) were slightly different. Late and operative mortality were higher in group 2 compared to groups 1 and 3. Postoperative functional status (NYHA) improved both in groups 1 and 2. In group 1, there was a decrease in ERO.

CONCLUSION

Mitral annuloplasty combined to revascularization improves symptoms, postoperative ERO and short- and mid-term survival compared with revascularization alone.