Mitral Valve Repair: The French Correction Versus the American Correction

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.

Anatomical and biometric study of the mitral valve apparatus: application in valve repair surgery

OBJECTIVE

Most mitral valve repair techniques provide excellent surgical results by removing regurgitation, but all of these techniques simultaneously reduce posterior valve mobility. A comprehensive biometric study of the mitral valve apparatus will provide landmarks that would help improve this posterior valve mobility.

MATERIALS AND METHODS

Thirty one (31) human hearts have been studied, from 14 women and 17 men. The characteristics of the studied sample were analyzed descriptively. The difference in means of the variables between women and men were tested using a Student t test. Correlations between the different measures were determined by simple regression analysis. Mean values are shown with ± 1 standard deviation and the limit of significance was set at 0.05.

RESULTS

The mean weight of the hearts was 275.3 ± 2.4 g. The anteroposterior diameter of the mitral annulus was 29.3 ± 1.22 mm, the intertrigonal distance was 25.2 ± 3.50 mm and the anterior leaflet to posterior leaflet ratio was 1.9 ± 0.10, the length of the chordae A2 = 19.4 ± 1.15 mm and P2 = 14.5 ± 0.85 mm. The length of the anterior papillary muscle averaged 30.9 ± 7.20 mm and that of the posterior one 30.0 ± 8.75 mm. The comparison of the different values measured between women and men showed no statistically significant difference (p > 0.05). There was no correlation between these different measured values (p > 0.05).

CONCLUSION

A perfect knowledge of anatomy and biometry is therefore essential to offer alternative techniques that reproduce the real anatomy and physiology with a complete reconstruction of the mitral valve.

Percutaneous MitraClip Device or Surgical Mitral Valve Repair in Patients With Primary Mitral Regurgitation Who Are Candidates for Surgery: Design and Rationale of the REPAIR MR Trial

Background The current standard of care for the treatment of patients with primary mitral regurgitation (MR) is surgical mitral valve repair. Transcatheter edge-to-edge repair with the MitraClip device provides a less invasive treatment option for patients with both primary and secondary MR. Worldwide, >150 000 patients have been treated with the MitraClip device. However, in the United States, MitraClip is approved for use only in primary patients with MR who are at high or prohibitive risk for mitral valve surgery. The REPAIR MR (Percutaneous MitraClip Device or Surgical Mitral Valve Repair in Patients With Primary Mitral Regurgitation Who Are Candidates for Surgery) trial is designed to compare early and late outcomes associated with transcatheter edge-to-edge repair with the MitraClip and surgical repair of primary MR in older or moderate surgical risk patients. Methods and Results The REPAIR MR trial is a prospective, randomized, parallel-controlled, open-label multicenter, noninferiority trial for the treatment of severe primary MR (verified by an independent echocardiographic core laboratory). Patients with severe MR and indications for surgery because of symptoms (New York Heart Association class II-IV), or without symptoms with left ventricular ejection fraction ≤60%, pulmonary artery systolic pressure >50 mm Hg, or left ventricular end-systolic diameter ≥40 mm are eligible for the trial provided they meet the moderate surgical risk criteria as follows: (1) ≥75 years of age, or (2) if <75 years of age, then the subject has a Society of Thoracic Surgeons Predicted Risk Of Mortality score of ≥2% for mitral repair (or Society of Thoracic Surgeons replacement score of ≥4%), or the presence of a comorbidity that may introduce a surgery-specific risk. The local surgeon must determine that the mitral valve can be surgically repaired. Additionally, an independent eligibility committee will confirm that the MR can be reduced to mild or less with both the MitraClip and surgical mitral valve repair with a high degree of certainty. A total of 500 eligible subjects will be randomized in a 1:1 ratio to receive the MitraClip device or to undergo surgical mitral valve repair (control group). There are 2 co-primary end points for the trial, both of which will be evaluated at 2 years. Each subject will be followed for 10 years after enrollment. The study has received approval from both the Food and Drug Administration and the Centers for Medicare and Medicaid Services, and enrolled its first subject in July 2020. Conclusions The REPAIR MR trial will determine the safety and effectiveness of transcatheter edge-to-edge repair with the MitraClip in patients with primary MR who are at moderate surgical risk and are candidates for surgical MV repair. The trial will generate contemporary comparative clinical evidence for the MitraClip device and surgical MV repair. Registration https://clinicaltrials.gov/ct2/show/NCT04198870; NCT04198870.

Quantitative in vivo assessment of human mitral valve coaptation area after undersized ring annuloplasty repair for ischemic mitral regurgitation

Objectives

Long-term outcomes of mitral valve repair procedures to correct ischemic mitral regurgitation remain unpredictable, due to an incomplete understanding of the disease process and the inability to reliably quantify the coaptation zone using echocardiography. Our objective was to quantify patient-specific mitral valve coaptation behavior from clinical echocardiographic images obtained before and after repair to assess coaptation restoration and its relationship with long-term repair durability.

Methods

To circumvent the limitations of clinical imaging, we applied a simulation-based shape-matching technique that allowed high-fidelity reconstructions of the complete mitral valve in the systolic configuration. We then applied this method to an extant database of human regurgitant mitral valves before and after undersized ring annuloplasty to quantify the effect of the repair on mitral valve coaptation geometry.

Results

Our method was able to successfully resolve the coaptation zone into distinct contacting and redundant regions. Results indicated that in patients whose regurgitation recurred 6 months postrepair, both the contacting and redundant regions were larger immediately postrepair compared with patients with no recurrence (P < .05), even when normalized to account for generally larger recurrent valves.

Conclusions

Although increasing leaflet coaptation area is an intuitively obvious way to improve long-term repair durability, this study has implied that this may not be a reliable target for mitral valve repair. This study underscores the importance of a rigorous understanding of the consequences of repair techniques on mitral valve behavior, as well as a patient-specific approach to ischemic mitral regurgitation treatment within the context of mitral valve and left ventricle function.

Surgical mitral valve repair technique considerations based on the available evidence

Mitral valve regurgitation is the second most common valve disease in the western world. Surgery is currently the best tool for generating a long-lasting elimination of mitral valve regurgitation. However, the mitral valve apparatus is a complex anatomical and functional structure, and repair results and durability show substantial heterogeneity. This is not only due to differences in the underlying mitral valve regurgitation pathophysiology but also due to differences in repair techniques. Repair philosophies differ substantially from one surgeon to the other, and consensus for the technically best repair strategy has not been reached yet. We had previously addressed this topic by suggesting that ring sizing is "voodoo". We now review the available evidence regarding the various repair techniques described for structural and functional mitral valve regurgitation. Herein, we illustrate that for structural mitral valve regurgitation, resuspension of prolapsing valve segments or torn chordae with polytetrafluoroethylene sutures and annuloplasty can generate the most durable results paired with the best achievable hemodynamics. For functional mitral valve regurgitation, the evidence suggests that annuloplasty alone is insufficient in most cases to generate durable results, and additional subvalvular strategies are associated with improved durability and possibly improved clinical outcomes. This review addresses current strategies but also implausibilities in mitral valve repair and informs the mitral valve surgeon about the current evidence. We believe that this information may help improve outcomes in mitral valve repair as the heterogeneity of mitral valve regurgitation pathophysiology does not allow a one-size-fits-all concept.

Mitral Valve Annuloplasty Failure and Percutaneous Treatment Options

PURPOSE OF REVIEW

Mitral valve repair is a common surgical procedure for both primary and secondary mitral regurgitation. With operations performed earlier in disease progression and increased patient longevity, the need for a repeat intervention is not infrequent. With the associated risks of reoperation and patient comorbidities, percutaneous techniques for acute or delayed failure after ring annuloplasty are emerging.

RECENT FINDINGS

Current commercially available devices, used in "off-label" ways, such as the MitraClip, may be effective in repairing recurrent mitral regurgitation after annuloplasty. Similarly, a valve-in-ring transcatheter mitral valve replacement can be considered in patients at high risk for surgical reoperation. These procedures are not without risk, for example, resultant mitral stenosis in the setting of edge-to-edge repair or left ventricular outflow tract (LVOT) obstruction with valve-in-ring transcatheter mitral valve replacement. Newer devices are emerging to permit more options for this subset of patients, which include transcatheter valves that are specifically designed for the mitral position. Undoubtedly, surgical reoperation has increased risk as compared to primary operation. Though percutaneous options are evolving, use in this patient population is currently limited to "off-label" use and is also associated with procedural complexities and risk. It is prudent for cardiologists, surgeons, and anesthesiologists to weigh risks, benefits, and limitations when considering patients for surgical reoperation, percutaneous repair, or transcatheter replacement after failed mitral annuloplasty.

Fluid-Structure Interaction Analyses of Biological Systems Using Smoothed-Particle Hydrodynamics

Due to the inherent complexity of biological applications that more often than not include fluids and structures interacting together, the development of computational fluid-structure interaction models is necessary to achieve a quantitative understanding of their structure and function in both health and disease. The functions of biological structures usually include their interactions with the surrounding fluids. Hence, we contend that the use of fluid-structure interaction models in computational studies of biological systems is practical, if not necessary. The ultimate goal is to develop computational models to predict human biological processes. These models are meant to guide us through the multitude of possible diseases affecting our organs and lead to more effective methods for disease diagnosis, risk stratification, and therapy. This review paper summarizes computational models that use smoothed-particle hydrodynamics to simulate the fluid-structure interactions in complex biological systems.

One Hundred Percent Reparability of Mitral Prolapse: Results of a Dynamic Nonresectional Technique

BACKGROUND

We studied the results of a dynamic mitral repair technique that preserves normal mitral valve function by avoiding leaflet resection and rigid and semirigid annuloplasty rings.

METHODS

In previous reports we demonstrated that intraoperative simulation of mitral valve locking and isovolumic systole by rapid left ventricular inflation with pressurized saline accurately simulates mitral annular and leaflet shape and position, and left ventricular outflow tract dimensions. Length of polytetrafluoroethylene neochordae and size of fully flexible adjustable annuloplasty ring can be adjusted in three dimensions for accurate apposition of zones of leaflet coaptation, premarked with dots. We followed 1068 consecutive patients after repairs performed between 2001 and 2018.

RESULTS

Of the 1068 patients, 674 were men (63.1%). Mean age was 62.25 ± 13 years. Leaflet repaired was anterior in 118 patients (11.05%), posterior in 564 (52.81%), both in 55 (5.15%), and neither in 123 (11.5%). Barlow's disease was present in 208 patients (19.48%). Repair was isolated in 82.5% (881 of 1068). Reparability was 100%. Perioperative mortality overall was 1.59% (17 of 1068): isolated repair, 1.14% (10 of 881); and isolated posterior leaflet, 0.85% (4 of 472). Leaflet systolic anterior motion occurred in 1.7% (18 of 1068), and was significant in 0.4% (4 of 1068). Survival at 10 years by Kaplan-Meier analysis was 74.65%, freedom from reoperation was 96.01%, and freedom from severe mitral regurgitation was 94%. The only predictor of reoperation (Cox analysis) was being male (P = .001).

CONCLUSIONS

Use of intraoperative simulation of mitral dynamics led to 100% reparability for degenerative valves with minimal systolic anterior motion, despite no leaflet resection. Long-term durability has been good and similar for all leaflets.

Ring-first Mitral Valve Repair

Mitral valve repair is one of the most frequent interventions in cardiac surgery. It involves eliminating the dysfunctional part(s) of the mitral valve and reconstructing, using the residual tissue or with the addition of prosthetic components, a properly functioning valve, without residual stenosis or regurgitation. A fundamental component of mitral repair is the implantation of a ring (annuloplasty) which reconstitutes the normal, saddle-shaped geometry of the valve. Such ring is usually implanted at the end of the surgical reconstruction regardless of the repair techniques. The implantation of the ring can however change the final anatomy of the valve in an unexpected way and therefore force new corrective surgical actions. We therefore propose a research project that plans the execution of annuloplasty as the first surgical step and then the correction of the valvular disease affecting the leaflets and chordae. The sizing of the ring is always performed on parts of the valve that are usually not changed during the reconstructive surgery, therefore it is possible to decide its size before surgically correcting the valve. In this way we could act on the leaflets and chordae in the definitive geometrical arrangement of the mitral valve.

Surgical treatment of mitral regurgitation

PURPOSE OF REVIEW

Mitral repair is the best treatment for degenerative mitral regurgitation. Many patients are referred too late for optimal outcomes. The US repair vs. replacement rate is only 60-80%, at a time when the inferiority of replacement has been established. Therefore, widely used traditional techniques of repair are being reappraised.

RECENT FINDINGS

Identification of risk factors predictive of poor early and late outcome have improved timing for surgical referral. Composite risk scores have been developed. Novel echocardiographic, cardiac MRI, and molecular level risk factors could improve timing. Analysis of factors contributing to low repair rates is also of critical importance. The role of institutional and surgeon volumes have been identified. More detailed data on the importance of dynamic function of the mitral valve have led to improved repair techniques such as intraoperative simulation of end diastole and early systole, use of expanded polytetrafluoroethylene neochords instead of leaflet resection, and dynamic instead of rigid annuloplasty.

SUMMARY

Our perception of mitral regurgitation has changed from a seemingly simple condition to one of considerable complexity at multiple levels. National guidelines should be studied and followed.

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.

Contemporary trends in mitral valve surgery in East China: a 10-year experience

Background

Contemporary nationwide data from mainland China on trends in mitral valve surgery are scarce. The purpose of the present study was to review a single-center experience with mitral valve surgery over a 10-year period in East China.

Methods

Between July 2009 and June 2019, 3238 consecutive patients who underwent mitral valve surgery in our center were retrospectively reviewed. The patients were evenly divided into three periods: July 2009 to October 2012 (period I), November 2012 to February 2016 (period II), March 2016 to June 2019 (period III).

Results

The 3238 patients included 536 (16.6%) who had mitral valve repair and 2702 (83.4%) who had mitral valve replacement. Early mortalities for mitral valve repair and mitral valve replacement were 0.2% and 0.9%, respectively. There were trends towards a higher proportion of degenerative valve lesions (24.6%, 35.8%, 54.7% in periods I, II, and III, respectively) and a lower proportion of rheumatic valve lesions (71.0%, 62.6%, 38.0%) in more recent years. The proportions of minimally invasive surgery (0.7%, 2.1%, 30.2%), mitral valve repair (8.3%, 15.4%, 27.5%), use of a bioprosthesis (10.1%, 17.0%, 23.1%), and concomitant tricuspid valve procedures (13.2%, 28.5%, 46.0%) increased dramatically, while early mortality remained constant during the 10-year period (1.0%, 0.3%, 0.9%).

Conclusions

In the past 10 years, the spectrum of mitral valve disease experienced a trend towards more degenerative valve lesions and less rheumatic valve lesions in East China. Mitral valve repair, bioprostheses, tricuspid valve repair, and minimally invasive surgery have been more often applied in recent years.

Intra-operative trans-esophageal echocardiography in heart valve disease

Peri-operative echocardiography is widely used because it provides information that significantly influences clinical/surgical management and improves outcome in patients undergoing cardiac surgery. The role of intra-operative trans-esophageal echocardiography (TEE) in valvular heart disease cannot be emphasized enough. Increasing use of newer surgical techniques-valve repairs and minimal invasive cardiac surgery also warrants intra-operative TEE. It gives us better insight into the anatomy and physiology of the valvular lesion by digital imaging. This manuscript provides an illustrative case based overview of intra operative TEE (IOTEE) in heart valve surgery.

Initial Application of a Bicuspid Aortic Annuloplasty Ring in Pediatric Cardiac Surgery

Aortic stenosis and aortic insufficiency (AI) are common valvular conditions that may necessitate repair or replacement of the aortic valve. Aortic valve replacement is associated with higher long-term complications and thus, a consistent, reliable method of repair is needed. This is especially true in the pediatric population where lifelong anticoagulation and development of recurrent aortic stenosisor aortic insufficiency are especially problematic. The Hemispherical Aortic Annuloplasty Reconstruction Technology ring has been developed and used for annular stabilization in adults with success, though its efficacy in the pediatric population has yet to be demonstrated. Herein, we discuss the use of a geometric ring in aortic valve repair for the pediatric patient.

Minimally Invasive Surgical Mitral Valve Repair: State of the Art Review

Minimally invasive surgical mitral valve repair (MVRepair) has become routine for the treatment of mitral valve regurgitation, and indications have been expanded to include reoperations. Current European Society of Cardiology/European Association for Cardio-Thoracic Surgery guidelines for the management of valvular heart disease recommended standards in terms of mitral valve disease differentiation, timing of intervention and surgical techniques to improve patient care. Numerous minimally invasive techniques to lessen the invasiveness have been described, such as the minimal-access J-sternotomy (ministernotomy), the parasternal incision, the port-access technique and the right minithoracotomy. Despite the development of catheter-based techniques, surgical repair remains the gold standard today for nearly all patients with degenerative valvular diseases and the majority of patients with other types of valvular diseases. Techniques include resection of the prolapsed segment, neo-chordae implantation and ring annuloplasty. In this review, the current indications for mitral valve surgery are summarised and state-of-the-art MVRepair techniques are highlighted.