Mechanism and severity of mitral regurgitation by transesophageal echocardiography in patients referred for percutaneous valve repair

Transcatheter Edge-to-Edge Repair in Valvular Heart Disease: A Comprehensive Exploration of Equipment, Efficacy, Gender, Racial, and Socioeconomic Disparities, and Future Prospects

The 2 primary components of valvular heart disease are mitral regurgitation (MR) and tricuspid regurgitation (TR). Transcatheter edge-to-edge repair (TEER) is an advanced, minimally invasive procedure that has recently displayed encouraging outcomes in the treatment of these pathologies. TEER offers a nonsurgical alternative for individuals diagnosed with conditions deemed to be high-risk surgical candidates. Currently, the TEER procedure employs devices such as MitraCLIP and TriCLIP, as well as innovative PASCAL (transcatheter valve repair system used for mitral and tricuspid valve repair) and FORMA (repair system used for tricuspid valve repair) repair systems. In the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial enrolling 614 patients to test the efficacy of TEER in MR, a significant reduction in hospitalization due to heart failure was observed at 24 months in the MitraClip + guideline-directed medical therapy (GDMT) group (35.8%) than in the GDMT-alone group (67.9%), HR, 0.53; P < 0.001, lower rate of all-cause mortality at 29.1% compared with 46.1% (P < 0.001), lower risk of cerebrovascular events (P = 0.001), and lower mortality due to cardiovascular events (P < 0.001). In another trial, patients with moderate TR or greater than New York Heart Association Class II or higher underwent TEER using the TriClip for the management of TR. The outcomes were encouraging, with 86% of patients showing a reduction in TR severity of at least one grade. As the technology and research surrounding TEER continue to progress, a more extensive range of patients are expected to qualify for TEER procedures. Our comprehensive review sought to extensively explore the background, equipment used, effectiveness of MR and TR, potential side effects, future prospects, and ongoing trials associated with TEER. We further discuss the existing gender, racial, and socioeconomic disparities in the realm of TEER.

Echocardiographic Outcomes With Transcatheter Edge-to-Edge Repair for Degenerative Mitral Regurgitation in Prohibitive Surgical Risk Patients

BACKGROUND

The CLASP IID randomized trial (Edwards PASCAL TrAnScatheter Valve RePair System Pivotal Clinical Trial) demonstrated the safety and effectiveness of the PASCAL system for mitral transcatheter edge-to-edge repair (M-TEER) in patients at prohibitive surgical risk with significant symptomatic degenerative mitral regurgitation (DMR).

OBJECTIVES

This study describes the echocardiographic methods and outcomes from the CLASP IID trial and analyzes baseline variables associated with residual mitral regurgitation (MR) ≤1+.

METHODS

An independent echocardiographic core laboratory assessed echocardiographic parameters based on American Society of Echocardiography guidelines focusing on MR mechanism, severity, and feasibility of M-TEER. Factors associated with residual MR ≤1+ were identified using logistic regression.

RESULTS

In 180 randomized patients, baseline echocardiographic parameters were well matched between the PASCAL (n = 117) and MitraClip (n = 63) groups, with flail leaflets present in 79.2% of patients. Baseline MR was 4+ in 76.4% and 3+ in 23.6% of patients. All patients achieved MR ≤2+ at discharge. The proportion of patients with MR ≤1+ was similar in both groups at discharge but diverged at 6 months, favoring PASCAL (83.7% vs 71.2%). Overall, patients with a smaller flail gap were significantly more likely to achieve MR ≤1+ at discharge (adjusted OR: 0.70; 95% CI: 0.50-0.99). Patients treated with PASCAL and those with a smaller flail gap were significantly more likely to sustain MR ≤1+ to 6 months (adjusted OR: 2.72 and 0.76; 95% CI: 1.08-6.89 and 0.60-0.98, respectively).

CONCLUSIONS

The study used DMR-specific echocardiographic methodology for M-TEER reflecting current guidelines and advances in 3-dimensional echocardiography. Treatment with PASCAL and a smaller flail gap were significant factors in sustaining MR ≤1+ to 6 months. Results demonstrate that MR ≤1+ is an achievable benchmark for successful M-TEER. (Edwards PASCAL TrAnScatheter Valve RePair System Pivotal Clinical Trial [CLASP IID]; NCT03706833).

Invasive hemodynamics are equivocal for functional outcomes after MitraClip

Objectives

To evaluate invasive hemodynamics in assessing MC therapy success as well as evaluate its effectiveness as a predictor of functional outcomes.

Background

Mitral regurgitation grade is a poor predictor of functional outcomes after a MitraClip. There is a paucity of data on invasive hemodynamics as a predictor of outcomes.

Methods

Sixty-nine patients underwent MC between 2015 and 2018 at the University of Minnesota Medical Center and were retrospectively analyzed. Invasive hemodynamics were performed before and after device deployment with transesophageal echocardiographic guidance. Statistical analysis was performed using STATA version 16. Student's t test was used for continuous variables and Pearson's chi-squared test for categorical variables. Mann-Whitney test was performed for continuous variables where data were not normally distributed. Logistic and linear regression were used to investigate relationships between variables and outcomes.

Results

A total of 69 patients were included in the study. The mean age was 83 (75-87) years and 38 (55%) were male. Eighty-one percentage had >/= NYHA III symptoms. Eighty-seven percentage had severe MR. Pulmonary capillary wedge pressure was 20 (15-24). Overall, there was significant improvement in left atrial pressure including mean left atrial pressure index, MR, and NYHA class after MC (<.001). There was no significant association between invasive hemodynamics (including left atrial mean pressure index or its reduction rate) and functional outcomes (p = NS). MR grade was also not predictive of functional outcomes.

Conclusion

Left atrial pressure may not be a significant predictor of functional outcomes, and, in isolation, may not be an improvement over MR grade.

Transcatheter mitral valve repair and replacement: the next frontier of transcatheter valve intervention

PURPOSE OF REVIEW

We summarize the recent developments in transcatheter mitral valve repair (TMVr) and replacement (TMVR), discuss determinants of MitraClip outcomes in various mitral regurgitation causes, and highlight newly emerging devices and randomized trials.

RECENT FINDINGS

The discordant results published in the two recent randomized trials for MitraClip, the COAPT and the MITRA-FR trial have led to the emergence of a new conceptual framework such as the proportionate versus disproportionate mitral regurgitation and hemodynamics assessment tools like the real-time continuous left atrial pressure monitoring. Learning curve and volume-outcome analyses and studies examining the MitraClip usage in patients with degenerative mitral regurgitation are recent developments that have influenced MitraClip regulation and coverage. Several trials for TMVr devices that take an alternative approach to the edge-to-edge repair are underway and advancements in the TMVR technologies are continuing to progress to fill the unmet needs of treating high surgical risk patients whose complex valve anatomy make TMVr unfeasible.

SUMMARY

Evidence supports careful analysis of the valve area and left ventricular function in addition to the left atrial hemodynamics will improve the MitraClip outcome. Operator experience plays a greater effect when achieving excellent results with 1+ or less residual mitral regurgitation whereas surgical MVr volume did not influence TMVr outcome. Interventions on the complex primary mitral regurgitation remain under the surgical domain, but MITRA high risk (HR) and REPAIR mitral regurgitation trials are underway to evaluate the role of MitraClip in high to intermediate surgical risk patients with primary mitral regurgitation. Despite the slow developments in TMVR, the results of the early trials of its devices are promising.

Percutaneous mitral valve prostheses: 2019 update

During the last few years, there has been significant advances in the treatment of patients with severe mitral incompetence either too high risk for surgery or inoperable, this because of the improvements in percutaneous mitral valve prostheses, as alternative to the transcatheter mitral repair techniques. Percutaneous mitral valve replacement offers several advantages over the repair techniques, such as the opportunity to treat mitral valve with different anatomic characteristics, even the more complex ones, and the occasion to correct completely mitral regurgitation. The development of such prostheses has been a long process, still on the making. During the initial stages of the procedure, the transapical approach was preferred. On the other hand, the transseptal approach, which has already been used in some patients, is the proper development path for this transcatheter technique. Many valvular prostheses have been produced, each using a different mechanism for secure anchoring and elimination of regurgitation. Early mortality for this procedure, although decreasing since the preliminary studies, is still high, not only because the technology is still in its initial phase but also for the very high risk of the patients treated. It is foreseeable, though, that in the near future, as the technology and patients selection improves, better results will follow.

Direct Percutaneous Mitral Annuloplasty in Patients With Functional Mitral Regurgitation: When and How

Mitral regurgitation (MR) is a frequent valvular disease among patients deemed too high risk for surgery. Echocardiography along with CT is the primary diagnostic tool for MR and offers a comprehensive 3D assessment in patient selection and screening for the optimal treatment method. The direct percutaneous mitral annuloplasty addresses the underlying mechanisms of functional MR with a less invasive, catheter-based approach. The here-described techniques proved a sufficient safety profile, delivered significant MR reduction in most of the cases, and were associated with a notable improvement of symptoms. Although long-term outcome assessment is needed to support these early reports, the percutaneous mitral annuloplasty is likely to set a new standard of treatment in the forthcoming future.

Multimodality imaging for the quantitative assessment of mitral regurgitation

The natural history of mitral regurgitation (MR) results in significant morbidity and mortality. Innovations in non-invasive imaging have provided new insights into the pathophysiology and quantification of MR, in addition to early detection of left ventricular (LV) dysfunction and prognostic assessment in asymptomatic patients. Transthoracic (TTE) and transesophageal (TOE) echocardiography are the mainstay for diagnosis, assessment and serial surveillance. However, the advance from 2D to 3D imaging leads to improved assessment and characterization of mitral valve (MV) disease. Cardiovascular magnetic resonance (CMR) is increasingly used for MR quantitation and can provide an alternative imaging method if echocardiography is suboptimal or inconclusive. Other techniques such as exercise echocardiography, tissue Doppler imaging and speckle-tracking echocardiography can further offer complementary information on prognosis. This review summarises the current evidence for state-of-the-art cardiovascular imaging for the investigation of MR. Whilst advanced echocardiographic techniques are superior in the evaluation of complex MV anatomy, CMR appears the most accurate technique for the quantification of MR severity. Integration of multimodality imaging for the assessment of MR utilises the advantages of each imaging technique and offers the most comprehensive assessment of MR.

An easy-to-use scoring index to determine severity of mitral regurgitation by 2D echocardiography in clinical practice

PURPOSE

Mitral regurgitation (MR) grading by two-dimensional transthoracic echocardiography is challenging, but important to determine the best treatment strategy in patients with MR. Current guidelines advocate an integrative approach, although no recommendation is provided on how to do so. An easy-to-use index will be helpful for standardized and reproducible MR grading.

METHODS

Eleven echocardiographic parameters were retrospectively evaluated in 145 patients with moderate or severe MR. Parameters were scored positive or negative for severe MR, where expert panel consensus reading was considered as the reference standard. Logistic regression was performed, and adjusted coefficients were used to create a risk score for severe MR per patient (ROSE-index). The best cutoff with corresponding predictive values was determined.

RESULTS

Eighty-two percent of all parameters could be determined. Multivariable analysis revealed five parameters that remained significant predictors for severe MR: morphology, jet characteristics, vena contracta, systolic reversal, and left ventricular dimensions. With different weighing, a total score of 8 could be obtained. Median total ROSE-index score for moderate (2.0) and severe MR (5.0) did significantly differ. The cutoff score (≥4) revealed sensitivity 0.84 and specificity 0.83 to diagnose severe MR. Negative predictive value was 100% for score 0 and 1; score 6-8 showed a 100% positive predictive value. Inter- and intra-observer agreements were excellent (K-values >0.80).

CONCLUSION

Here, we propose an easy-to-use tool for integrated analysis of guideline parameters to assess MR severity. Using this so-called ROSE-index revealed reliable and reproducible assessment of severe MR (cutoff≥4) that may be helpful for clinical decision making.

Three-Dimensional Field Optimization Method: Gold-Standard Validation of a Novel Color Doppler Method for Quantifying Mitral Regurgitation

BACKGROUND

Accurate diagnosis of mitral regurgitation (MR) severity is central to proper treatment. Although numerous approaches exist, an accurate, gold-standard clinical technique remains elusive. The authors previously reported on the initial development and demonstration of the automated three-dimensional (3D) field optimization method (FOM) algorithm, which exploits 3D color Doppler ultrasound imaging and builds on existing MR quantification techniques. The aim of the present study was to extensively validate 3D FOM in terms of accuracy, ease of use, and repeatability.

METHODS

Three-dimensional FOM was applied to five explanted ovine mitral valves in a left heart simulator, which were systematically perturbed to yield a total of 29 unique regurgitant geometries. Three-dimensional FOM was compared with a gold-standard flow probe, as well as the most clinically prevalent MR volume quantification technique, the two-dimensional (2D) proximal isovelocity surface area (PISA) method.

RESULTS

Overall, 3D FOM overestimated and 2D PISA underestimated MR volume, but 3D FOM error had smaller magnitude (5.2 ± 9.9 mL) than 2D PISA error (-6.9 ± 7.7 mL). Two-dimensional PISA remained superior in diagnosis for round orifices and especially mild MR, as predicted by ultrasound physics theory. For slit-type orifices and severe MR, 3D FOM showed significant improvement over 2D PISA. Three-dimensional FOM processing was technically simpler and significantly faster than 2D PISA and required fewer ultrasound acquisitions. Three-dimensional FOM did not show significant interuser variability, whereas 2D PISA did.

CONCLUSIONS

Three-dimensional FOM may provide increased clinical value compared with 2D PISA because of increased accuracy in the case of complex or severe regurgitant orifices as well as its greater repeatability and simpler work flow.

Percutaneous Mitral Annuloplasty

Percutaneous mitral valve therapies are emerging as an alternative option for high-risk patients who are not good candidates for conventional open-heart surgery. Recently, multiple technologies and diversified approaches have been developed and are under clinical study or in preclinical development. This article on transcatheter mitral annuloplasty devices, describes the different technologies, and reports on the initial clinical and preclinical experiences.

Current status and clinical development of transcatheter approaches for severe mitral regurgitation

Transcatheter mitral valve intervention has emerged as an effective treatment option for symptomatic severe mitral regurgitation in patients considered to be inoperable or at high operative risk for surgical mitral valve surgery. Most transcatheter approaches are modifications of existing surgical approaches. Transcatheter edge-to-edge mitral valve repair with the MitraClip system has the largest clinical experience to date, as it offers a sustained clinical benefit in selected patients. This review aims to provide an up-to-date overview of transcatheter mitral valve interventions, including leaflet repair, annuloplasty, and mitral valve implantation.

Transcatheter mitral valve repair therapies for primary and secondary mitral regurgitation

Mitral regurgitation is one of the most prevalent valvular heart diseases and its prevalence is related to population aging. Elderly patients with age-associated co-morbidities have an increased risk for conventional mitral valve surgery. Transcatheter mitral valve repair has emerged as a feasible and safe alternative in patients with contraindications for surgery or high operative risk. Several transcatheter mitral repair technologies have been developed during the last decade. While the development of some devices was abandoned due to suboptimal results, others demonstrated to be safe and effective and have been included in current practice guidelines. Not all technologies are suitable for all mitral anatomies and regurgitation mechanisms. Therefore, accurate evaluation of mitral valve anatomy and function are pivotal to the success of these therapies. Cardiac imaging plays a central role in selecting patients, guiding the procedure and evaluating the durability of the repair at follow-up.

Timing of surgery in valvular heart disease: prophylactic surgery vs watchful waiting in the asymptomatic patient

In the absence of randomized controlled trial data, the management of patients with severe valvular heart disease without symptoms, ventricular dysfunction, or other identified triggers for surgery is controversial. In this review, we frame the debate between prophylactic surgery vs close follow-up until triggers occur (watchful waiting) for severe aortic stenosis and degenerative mitral regurgitation (MR), the 2 conditions for which the pros and cons of these approaches are best articulated. Classic high-gradient severe aortic stenosis is generally accurately diagnosed. In asymptomatic patients, stress testing can be used to confirm asymptomatic status and identify high-risk features including reduced exercise tolerance, exercise-induced symptoms, and absolute or relative hypotension. Resting echocardiographic predictors of disease progression and/or adverse events include very high gradients, rapid progression, and extensive calcification. Surgical risk calculators can help estimate perioperative morbidity/mortality with the ultimate choice of a medical vs a prophylactic surgical approach to be made after discussion with the patient. With degenerative MR, severity can be inaccurately estimated. Stress testing might clarify whether the patient is truly asymptomatic and identify features associated with worse prognosis and symptom onset. Selecting patients with high probability of repair can be challenging. Perioperative risk and postoperative risks including those of unanticipated valve replacement and recurrent MR after repair are also considerations. In aggregate, management of patients with valvular disease who are asymptomatic and who have no clear trigger for surgery is complex, requires individualization, and should be carried out by or in collaboration with a heart valve centre of excellence.

Devices for mitral valve repair

The natural history of severe mitral regurgitation (MR) is unfavorable, leading to left ventricular failure, atrial fibrillation, stroke, and death. Many patients affected by severe regurgitation (MR) do not currently undergo surgery, mainly due to the perceived risk of the procedure (old age, impaired left ventricular function, and comorbidities). Mitral transcatheter interventions carry the hope of minimizing risks while preserving clinical efficacy of surgical repair, as an alternative to conventional treatment. Multiple technologies and diversified approaches are under development with the purpose of treating MR in less invasive ways. They can be categorized based on the anatomical and patho-physiological addressed target. Among them, MitraClip (Abbott Vascular, Inc., Menlo Park, California) has emerged as a clinically safe and effective method for percutaneous mitral valve repair in patients either with degenerative and functional regurgitation. This device mimics the surgical edge-to-edge repair initially described by Alfieri in the early 1990s. Other repair technologies include percutaneous direct and indirect annuloplasty, neochordae implantation, and left ventricular reshaping. They are still in early phase clinical trials or preclinical studies. The combination of different repair techniques is likely to be required to achieve good long-lasting results. In the future, novel devices, improved knowledge, more efficient imaging, and transcatheter mitral prosthetic valve implantation may expand the indications to those patients currently not treated, as well as improve the results both in terms of early efficacy and long-term durability. These treatments are currently reserved to high-risk and inoperable patients, and their application requires an integrated Heart-Team approach. They represent the natural evolution of surgery and promise to expand treatment options and improve patients' outcomes in the near future.

Relationship between the magnitude of reduction in mitral regurgitation severity and left ventricular and left atrial reverse remodeling after MitraClip therapy

BACKGROUND

MitraClip has been shown to reduce mitral regurgitation (MR) severity safely but to a lesser degree than surgery. No data exist on the magnitude of MR reduction necessary to reverse left ventricular (LV) and left atrial (LA) dilation in patients with severe MR. Therefore, an analysis was performed to evaluate the relationship between MR reduction and LV and LA volumes after MitraClip therapy.

METHODS AND RESULTS

A total of 801 patients treated with MitraClip and 80 patients treated surgically were included. All patients had severe (3-4+) MR. MR severity, LV volumes at end-diastole and end-systole, and LA volumes were measured at baseline, discharge, 30 days, 6 months, and 1 year by an independent echocardiographic core laboratory. A linear repeated measures model was developed to determine the relationship between MR severity and time of measurement postindex procedure on longitudinal LV and LA volumes. Separate models were fit for functional MR and degenerative MR. In both degenerative and functional MR, reduction in LV volumes at end-diastole was associated with degree of residual MR at 12 months (P<0.0001). LV volumes at end-systole was significantly reduced in functional MR but not degenerative MR. LA volumes were significantly related to reduction of MR severity in both groups.

CONCLUSIONS

Reduction of LV volumes at end-diastole and LA volumes, but not LV volumes at end-systole in degenerative MR, is consistent with correction of volume overload from primary MR. Reduction of all 3 measurements in functional MR demonstrates reverse remodeling when MR severity is reduced to either 1+ or 2+ by MitraClip therapy.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT00209274.

Mitral transcatheter technologies

Mitral valve regurgitation (MR) is often diagnosed in patients with heart failure and is associated with worsening of symptoms and reduced survival. While surgery remains the gold standard treatment in low-risk patients with degenerative MR, in high-risk patients and in those with functional MR, transcatheter procedures are emerging as an alternative therapeutic option. MitraClip(®) is the device with which the largest clinical experience has been gained to date, as it offers sustained clinical benefit in selected patients. Further to MitraClip implantation, several additional approaches are developing, to better match with the extreme variability of mitral valve disease. Not only repair is evolving, initial steps towards percutaneous mitral valve implantation have already been undertaken, and initial clinical experience has just started.

[Current value of 3D echocardiography in international guidelines]

Real-time 3D echocardiography is one of the most important developments in the field of non-invasive cardiac imaging within the last years. To investigate whether this new technology can be considered as a standard method the current guidelines and recommendations were reviewed. In the field of left ventricular function assessment, evaluation of mitral valve pathologies and peri-interventional monitoring of percutaneous valve repair procedures 3D echocardiography plays a major role. For other clinical applications, such as right heart assessment, congenital heart disease and stress echocardiography, a high potential is seen but evidence is currently too weak for general recommendations. However, in the near future no echo laboratory will be working without 3D modalities.