Transcatheter Therapy for Mitral Regurgitation Clinical Challenges and Potential Solutions

Three-dimensional printing in modelling mitral valve interventions

Mitral interventions remain technically challenging owing to the anatomical complexity and heterogeneity of mitral pathologies. As such, multi-disciplinary pre-procedural planning assisted by advanced cardiac imaging is pivotal to successful outcomes. Modern imaging techniques offer accurate 3D renderings of cardiac anatomy; however, users are required to derive a spatial understanding of complex mitral pathologies from a 2D projection thus generating an 'imaging gap' which limits procedural planning. Physical mitral modelling using 3D printing has the potential to bridge this gap and is increasingly being employed in conjunction with other transformative technologies to assess feasibility of intervention, direct prosthesis choice and avoid complications. Such platforms have also shown value in training and patient education. Despite important limitations, the pace of innovation and synergistic integration with other technologies is likely to ensure that 3D printing assumes a central role in the journey towards delivering personalised care for patients undergoing mitral valve interventions.

Mitral Valve Replacement: A Review of Current Practices and Considerations in Low and High-Risk Patients

Mitral Regurgitation (MR) is the most common form of severe valvular disease occurring in developed countries, being caused either primarily on its own or secondary to cardiac disease. Surgical intervention is required for the correction of MR, which could include the replacement or repair of the affected valve. Transcatheter Mitral Valve Replacement (TMVR) in selected patients is of increasing importance, especially after the success of Transcatheter Aortic Valve Replacement (TAVR). TMVR can be divided into three types i.e., valve-in-valve (ViV) for severe mitral valve disease, valve-in-ring (ViR) for failed surgical repairs, and valve-in-mitral annular calcifications (ViMAC) for mitral valvular disease with severe mitral annular calcifications and poor surgical criteria. The FDA approved Mitral ViV for patients with a high surgical risk in 2017, while ViR and ViMAC are still currently under consideration. The SAPIEN M3 valve is relatively new with a trans-septal system, with a success rate of 86%, and no mortality in a 30-day outcome. The Cardiovalve is a bovine pericardium device that has a dual nitinol frame with a custom surgical design to facilitate TMVR. The AHEAD trial will evaluate whether the device is safe to use in a clinical setting and how effective it is for reducing MR in these patients. The trial consists of 30 patients in which the first 5 patients showed 100% technical success and a reduction of MR. This evolution of modern medicine has assisted in many different countries, including Pakistan where there is a higher prevalence of MR and hence, a greater need to apply TMVR in clinical practice.

Stereogram of the Living Heart, Lung, and Adjacent Structures

Innovations in invasive cardiovascular diagnostics and therapeutics, not only limited to transcatheter approaches but also involving surgical approaches, are based on a precise appreciation of the three-dimensional living heart anatomy. Rapid advancements in three-dimensional cardiovascular imaging technologies in the 21st century have supported such innovations through the periprocedural assessment of the clinical anatomy of the living heart. However, even if high-resolution volume-rendered images are reconstructed, they cannot provide appropriate depth perception when displayed and shared on a two-dimensional display, which is widely used in clinical settings. Currently, images reconstructed from clinical datasets can visualize fine details of the cardiovascular anatomy. Therefore, this is an optimal time for cardiologists and cardiac surgeons to revisit the classic technology, stereopsis, and obtain bonus information from carefully reconstructed clinical images. Using anaglyphs or cross/uncross-fusion of paired images, striking depth perception can be readily obtained without the need for expensive equipment. This conventional technique, when applied to high-resolution volume-rendered images, may help in obtaining appropriate diagnostics, choosing optimal therapeutics, securing procedural success, and preventing complications. Furthermore, it can be used for anatomical education. In this review, we demonstrate multiple stereoscopic images reconstructed from cardiac computed tomographic datasets and discuss their clinical and educational implications.

Relation of Guideline Adherence to Outcomes in Patients With Asymptomatic Severe Primary Mitral Regurgitation

Current guidelines empirically recommend serial clinical evaluations for asymptomatic patients with severe mitral regurgitation (MR). However, there is a paucity of data on the effectiveness of such monitoring. This study sought to examine the potential benefit of guideline adherence among asymptomatic patients with severe primary MR. Asymptomatic patients with severe primary MR who had been evaluated in the Allina Health system between January 1, 2012 and May 30, 2018 were examined. The medical records were manually reviewed for demographics, comorbidities, echocardiographic data, subsequent interventions, and clinical outcomes. Patients were grouped according to occurrence of guideline adherence, which was defined as a serial clinical evaluation with echocardiography every 12 ± 1 month until mitral valve surgery, or death. Over the study period, 246 patients (67.3 ± 15.5 years, 61.4% men) with severe, asymptomatic primary MR were identified, including 154 patients (62.6%) with and 92 patients (37.4%) without guideline adherence. Overall, there were no differences in demographics, morbidities, MR severity, or left ventricular function between patient adherence groups. During follow-up (40.9; 21.2, 58.3 months), patients with adherence more frequently had surgery or transcatheter therapy performed (64.3% vs 18.5%; p <0.001) and the time to intervention was earlier (13.6 [3.9-22.7] vs 44.2[25.6-57.3] months; p <0.001). Compared to non-adherent patients, those with guideline adherence had a significantly higher five-year survival free from all-cause mortality (92.0% vs 74.3%, p = 0.002), and freedom from death or hospitalization for heart failure (90.1% vs 69.3%, p = 0.001). Adherent patients also had a significantly better survival free from combined endpoint of death, re-hospitalization for heart failure, myocardial infarction, and stroke (84.5% vs 63.2%, p = 0.002). In patients with asymptomatic severe primary MR, guideline adherence with serial evaluations every 12 months or less is associated with earlier therapy and improved long-term outcomes. These data support educational efforts to promote guideline adherence.

Long-term clinical and haemodynamic results after transcatheter annuloplasty for secondary mitral regurgitation

AIMS

The study sought to investigate the long-term outcome after transcatheter mitral valve annuloplasty for secondary mitral regurgitation (MR).

METHODS AND RESULTS

Consecutive patients with symptomatic secondary MR undergoing transcatheter mitral valve annuloplasty with the Carillon device at Leipzig University Hospital between 2012 and 2018 were studied prospectively. Left ventricular (LV) function and MR severity were quantified by standardized echocardiography. 33 patients were included. Mean age was 75 ± 10 years, and 20 patients were women. A Society of Thoracic Surgeons score of 8.1 ± 7.2% indicated high-risk status. In 24 patients, MR resulted from LV remodelling and dysfunction, eight suffered from left atrial dilatation, and one patient had MR due to combined primary and secondary aetiology. LV ejection fraction at baseline was (median) 38% [inter-quartile range (IQR) 30-49%]. During the mean follow-up time of 45 ± 20 months, 17 patients died, two patients withdraw consent, and four patients were lost. Of the remaining patients, four were hospitalized for decompensated heart failure. Two of these patients underwent additional transcatheter edge-to-edge mitral valve repair. At follow-up, New York Heart Association (NYHA) functional class improved from 95% in Class III/IV at baseline to 70% in Class I/II with no patients in NYHA Class IV (P < 0.0001). Mitral regurgitant volume was reduced from 27 mL (IQR 25-42 mL) to 8 mL (IQR 3-17 mL) (P = 0.018) and regurgitant fraction from 42% (IQR 34-54%) to 11% (IQR 8-24%) (P = 0.014). LV end-diastolic volume index [92 mL/m2 (IQR 74-107 mL/m2 ) vs. 67 mL/m2 (IQR 46-101 mL/m2 ), P = 0.065] and end-systolic volume index [50 mL/m2 (IQR 44-69 mL/m2 ) vs. 32 mL/m2 (IQR 20-53 mL/m2 ), P = 0.037] decreased. Total stroke volume remained unchanged [38 mL/m2 (IQR 33-43 mL/m2 ) vs. 33 mL/m2 (IQR 26-44 mL/m2 ), P = 0.695], while LV ejection fraction increased [43% (IQR 35-49%) vs. 54% (IQR 46-57%), P = 0.014]. Forward stroke volume, heart rate, and forward cardiac output were not significantly altered.

CONCLUSIONS

Among high-risk patients undergoing transcatheter mitral valve annuloplasty for symptomatic secondary MR, mortality was ~50% at 4 years. In the surviving patients, reduced MR severity was associated with reduced NYHA functional class, reverse LV remodelling, and improved LV function.

1-Year Outcomes for Transcatheter Repair in Patients With Mitral Regurgitation From the CLASP Study

OBJECTIVES

The authors report the CLASP (Edwards PASCAL Transcatheter Mitral Valve Repair System Study) expanded experience, 1-year outcomes, and analysis by functional mitral regurgitation (FMR) and degenerative mitral regurgitation (DMR).

BACKGROUND

The 30-day results from the CLASP study of the PASCAL transcatheter valve repair system for clinically significant mitral regurgitation (MR) have been previously reported.

METHODS

Eligible patients had symptomatic MR ≥3+, were receiving optimal medical therapy, and were deemed candidates for transcatheter mitral repair by the local heart team. Primary endpoints included procedural success, clinical success, and major adverse event rate at 30 days. Follow-up was continued to 1 year.

RESULTS

One hundred nine patients were treated (67% FMR, 33% DMR); the mean age was 75.5 years, and 57% were in New York Heart Association functional class III or IV. At 30 days, there was 1 cardiovascular death (0.9%), MR ≤1+ was achieved in 80% of patients (77% FMR, 86% DMR) and MR ≤2+ in 96% (96% FMR, 97% DMR), 88% of patients were in New York Heart Association functional class I or II, 6-min walk distance had improved by 28 m, and Kansas City Cardiomyopathy Questionnaire score had improved by 16 points (p < 0.001 for all). At 1 year, Kaplan-Meier survival was 92% (89% FMR 96% DMR) with 88% freedom from heart failure hospitalization (80% FMR, 100% DMR), MR was ≤1+ in 82% of patients (79% FMR, 86% DMR) and ≤2+ in 100% of patients, 88% of patients were in New York Heart Association functional class I or II, and Kansas City Cardiomyopathy Questionnaire score had improved by 14 points (p < 0.001 for all).

CONCLUSIONS

The PASCAL transcatheter valve repair system demonstrated a low complication rate and high survival, with robust sustained MR reduction accompanied by significant improvements in functional status and quality of life at 1 year. (The CLASP Study Edwards PASCAL Transcatheter Mitral Valve Repair System Study [CLASP]; NCT03170349).

Imaging for Native Mitral Valve Surgical and Transcatheter Interventions

There has been rapid progress in transcatheter therapies for mitral regurgitation. These developments have elevated the need for the imager to have a core understanding of the functional mitral valve anatomy. Pre- and intraoperative echocardiography for surgical mitral valve repair for mitral regurgitation has defined contemporary interventional imaging in many ways. The central tenets of these principles apply to interventional imaging of transcatheter mitral valve interventions. However, the heightened emphasis on procedural planning and procedural imaging is one of the new challenges posed by transcatheter interventions. This need for accurate and reliable information has required the imager to be agnostic to the imaging modality. Cardiac computed tomography has become critical in procedural planning in this new paradigm. The expanded use of pre-procedural cardiac magnetic resonance to quantify mitral regurgitation and characterize the left ventricle is another illustration of this newer approach. Other illustrations of the new world of interventional imaging include the expanded use of 3-dimensional (3D) transesophageal echocardiography and real-time fusion of echocardiography and fluoroscopy images. Imaging data are also the basis for computational modeling, 3D printing, and artificial intelligence. These technologies are being increasingly explored to improve therapy selection and prediction of procedural outcomes. This review provides an update of the essentials in present interventional imaging for surgical and transcatheter interventions for mitral regurgitation.

Devices for transcatheter mitral valve repair: current technology and a glimpse into the future

Introduction: Due to a large unmet need for the treatment of mitral regurgitation, transcatheter mitral valve repair devices have emerged in the last decade as an alternative therapeutic option. Given the complexity of this disease, several device systems for transcatheter mitral valve repair have been developed and are categorized according to its mechanism of action; each device has advantages and disadvantages for certain clinical and pathophysiologic characteristics, and in order to improve outcomes, proper patient selection among other key points are fundamental.Areas covered: The purpose of this article is to review the current state-of-the-art technologies available for transcatheter mitral valve repair, patient suitability, outcomes, and future perspectives.Expert opinion: Transcatheter therapy for mitral regurgitation improves outcomes and pushes the boundaries of biomedical technology while maintaining scientific rigor for device development. Surgical and percutaneous procedures should be viewed as complements to treat a wider spectrum of patients affected by this entity. Future directions from multidisciplinary innovation and cooperation will consolidate this therapeutic option.

Current Devices and Complications Related to Transcatheter Mitral Valve Replacement: The Bumpy Road to the Top

Mitral regurgitation is the most common valvular lesion in the developed world, with increasing prevalence, morbidity, and mortality. The experience with surgical mitral valve repair or replacement is very well-validated. However, more than 45% of these patients get denied surgery due to an elevated risk profile and advanced disease of the left ventricle at the time of presentation, promoting the need for less invasive transcatheter options such as transcatheter repair and transcatheter mitral valve replacement (TMVR). Early available TMVR studies have shown promising results, and several dedicated devices are under clinical evaluation. However, TMVR is still in the early developmental stages and is associated with a non-negligible risk of periprocedural and post-procedural complications. In this review, we discuss the current challenges facing TMVR and the potential TMVR-related complications, offering an overview on the measures implemented to mitigate these complications, and future implications.

Transcatheter mitral valve thrombosis: A case report and literature review

Transcatheter mitral valve replacement (TMVR) is an exciting alternative therapy for complex patients with mitral valve disease. Experience with TMVR is new and there is a lot yet to discover about their durability, long-term outcomes, and complications including mitral transcatheter heart valve (THV) thrombosis. Many factors have been speculated to increased risk of THV thrombosis. Here, we report a case of a 72-year-old woman who developed mitral THV thrombosis after undergoing TMVR for severe mitral regurgitation with mitral annular calcification. We reviewed 42 TMVR papers with 1,484 patients, including 60 with mitral THV thrombosis. We discussed the most common strategies used for mitral THV thromboprophylaxis and treatment.

Selection of the Optimal Candidate to MitraClip for Secondary Mitral Regurgitation: Beyond Mitral Valve Morphology

Secondary mitral regurgitation (MR) occurs despite structurally normal valve apparatus due to an underlying disease of the myocardium leading to disruption of the balance between tethering and closing forces with ensuing failure of leaflet coaptation. In patients with heart failure (HF) and left ventricular dysfunction, secondary MR is independently associated with poor outcome, yet prognostic benefits related to the correction of MR have remained elusive. Surgery is not recommended for the correction of secondary MR outside coronary artery bypass grafting. Percutaneous mitral valve repair (PMVR) with MitraClip implantation has recently evolved as a new transcatheter treatment option of inoperable or high-risk patients with severe MR, with promising results supporting the extension of guideline recommendations. MitraClip is highly effective in reducing secondary MR in HF patients. However, the derived clinical benefit is still controversial as two randomized trials directly comparing PMVR vs. optimal medical therapy in severe secondary MR yielded virtually opposite conclusions. We reviewed current evidence to identify predictors of PMVR-related outcomes in secondary MR useful to improve the timing and the selection of patients who would derive maximal benefit from MitraClip intervention. Beyond mitral valve anatomy, optimal candidate selection should rely on a comprehensive diagnostic workup and a fine-tuned risk stratification process aimed at (i) recognizing the substantial heterogeneity of secondary MR and its complex interaction with the myocardium, (ii) foreseeing hemodynamic consequences of PMVR, (iii) anticipating futility and (iv) improving symptoms, quality of life and overall survival.

Causes and mechanisms of isolated mitral regurgitation in the community: clinical context and outcome

AIMS

To define the hitherto unknown aetiology/mechanism distributions of mitral regurgitation (MR) in the community and the linked clinical characteristics/outcomes.

METHODS AND RESULTS

We identified all isolated, moderate/severe MR diagnosed in our community (Olmsted County, MN, USA) between 2000 and 2010 and classified MR aetiology/mechanisms. Eligible patients (n = 727) were 73 ± 18 years, 51% females, with ejection fraction (EF) 49 ± 17%. MR was functional (FMR) in 65%, organic (OMR) in 32% and 2% mixed. Functional MR was linked to left ventricular remodelling (FMR-v) 38% and isolated atrial dilatation (FMR-a) 27%. At diagnosis FMR-v vs. FMR-a, vs. OMR displayed profound differences (all P < 0.0001) in age (73 ± 14, 80 ± 10, 68 ± 21years), male-sex (59, 33, 51%), atrial-fibrillation (28, 54, 13%), EF (33 ± 14, 57 ± 11, 61 ± 10%), and regurgitant-volume (38 ± 13, 37 ± 11, 51 ± 24 mL/beat). Dominant MR mechanism was Type I (normal valve-movement) 38%, Type II (excessive valve-movement) 25%, Type IIIa (diastolic movement-restriction) 3%, and Type IIIb (systolic movement-restriction) 34%. Outcomes were mediocre with excess-mortality vs. general-population in FMR-v [risk ratio 3.45 (2.98-3.99), P < 0.0001] but also FMR-a [risk ratio 1.88 (1.52-2.25), P < 0.0001] and OMR [risk ratio 1.83 (1.50-2.22), P < 0.0001]. Heart failure was frequent, particularly in FMR-v (5-year 83 ± 3% vs. 59 ± 4% FMR-a, 40 ± 3% OMR, P < 0.0001). Mitral surgery during patients' lifetime was performed in 4% of FMR-v, 3% of FMR-a, and 37% of OMR.

CONCLUSION

Moderate/severe isolated MR in the community displays considerable aetiology/mechanism heterogeneity. Functional MR dominates, mostly FMR-v but FMR-a is frequent and degenerative MR dominates OMR. Outcomes are mediocre with excess-mortality particularly with FMR-v but FMR-a, despite normal EF incurs notable excess-mortality and frequent heart failure. Pervasive undertreatment warrants clinical trials of therapies tailored to specific MR cause/mechanisms.

Transcatheter mitral valve repair: review of current techniques

Mitral regurgitation is common and is associated with excess morbidity and mortality. Despite these poor outcomes, only a minority of affected patients undergo mitral surgery, for several reasons, which underlines the substantial unmet need for treatment for this disorder. Transcatheter mitral valve repair interventions have been developed to treat mitral regurgitation in an undertreated patient population. The aim of this status quo review is to provide an overview of currently available transcatheter mitral valve repair techniques, the different approaches and the clinical outcomes reported so far.

Causes and Clinical Outcomes of Patients Who Are Ineligible for Transcatheter Mitral Valve Replacement

OBJECTIVES

The aim of this study was to gain insight into the causes and outcomes of patients who do not qualify for transcatheter mitral valve replacement (TMVR).

BACKGROUND

Despite the increasing availability of TMVR, patients with severe mitral regurgitation may not be eligible. Thus far, no investigation has examined ineligible patients and their clinical outcomes.

METHODS

A total of 203 patients (mean age 79 ± 9 years, 48% men) who were ineligible for participation in early feasibility studies of TMVR were examined.

RESULTS

The ineligibility rate for TMVR was 89.0%. The most common reasons for TMVR exclusion were excessive frailty (15.3%), severe tricuspid regurgitation (15.3%), and prior aortic valve therapy (14.2%). Mitral anatomic exclusions were present in 15.8%, with severe annular calcification in 7.4%, and risk for left ventricular outflow tract obstruction was notably infrequent (4.4%). Overall, 76 patients (37.4%) did not undergo subsequent commercial surgical or transcatheter mitral therapy. Patients not eligible for TMVR and not treated commercially had high rates of cardiac death (11.8%) and death or heart failure hospitalization (22.4%) at 1 year. These rates were significantly higher than those who underwent surgery (2.4% for cardiac death; p < 0.001; 5.5% for heart failure hospitalization; p = 0.003) and remained worse after excluding patients with excessive frailty or medical futility and in multivariate modeling that adjusted for baseline differences.

CONCLUSIONS

Patients ineligible for TMVR and treated medically have poor outcomes. These data and the high rate of TMVR screen failure support the need for therapy iteration as well as development of alternative means of management, with the goal of improving the prognosis of these patients.

A workflow for patient-specific fluid-structure interaction analysis of the mitral valve: A proof of concept on a mitral regurgitation case

The mechanics of the mitral valve (MV) are the result of the interaction of different anatomical structures complexly arranged within the left heart (LH), with the blood flow. MV structure abnormalities might cause valve regurgitation which in turn can lead to heart failure. Patient-specific computational models of the MV could provide a personalised understanding of MV mechanics, dysfunctions and possible interventions. In this study, we propose a semi-automatic pipeline for MV modelling based on the integration of state-of-the-art medical imaging, i.e. cardiac magnetic resonance (CMR) and 3D transoesophageal-echocardiogram (TOE) with fluid-structure interaction (FSI) simulations. An FSI model of a patient with MV regurgitation was implemented using the finite element (FE) method and smoothed particle hydrodynamics (SPH). Our study showed the feasibility of combining image information and computer simulations to reproduce patient-specific MV mechanics as seen on medical images, and the potential for efficient in-silico studies of MV disease, personalised treatments and device design.

Left Ventricular Size Predicts Clinical Benefit After Percutaneous Mitral Valve Repair for Secondary Mitral Regurgitation: A Systematic Review and Meta-Regression Analysis

BACKGROUND

The benefit of percutaneous mitral valve repair (PMVR) in patients with secondary MR is still debated. We aimed to compare the outcome of PMVR with optimal medical therapy (OMT) versus OMT alone in patients with secondary mitral regurgitation (MR) and to assess the role of potential effect modifiers.

METHODS

We performed a systematic review and meta-analysis of 2 randomized clinical trials (RCT) and 7 non-randomized observational studies (nROS). Hazard ratios (HR) and 95% confidence intervals (CI) were pooled through inverse variance random-effects model to compute the summary effect size for all-cause death, cardiovascular death and cardiac-related hospitalization. Subgroup and meta-regression analysis were also performed.

RESULTS

An overall population of 3118 individuals (67% men; mean age, 73 years) was included: 1775 PMVR+OMT and 1343 OMT patients, with mean follow-up of 24 ± 15 months. PMVR+OMT was associated with a lower risk of all-cause death (HR: 0.77; 95% CI: 0.68-0.87), cardiovascular death (HR: 0.55; 95% CI: 0.34-0.89) and cardiac-related hospitalization (HR:0.77; 95% CI: 0.64-0.92). Meta-regression analysis showed that larger left ventricular end-diastolic volume index (LVEDVI) portends higher risk of all-cause death, cardiovascular death and cardiac-related hospitalization after PMVR (p < 0.001 for all).

CONCLUSIONS

This study-level meta-analysis shows that PMVR+OMT is associated with reduced all-cause death, cardiovascular death and cardiac-related hospitalization when compared with OMT alone in secondary MR. LVEDVI is a predictive marker of efficacy, as patients with smaller LVEDVI have been shown to derive the largest benefit from PMVR.

Transcatheter mitral valve repair: review of the clinical evidence

Over the past decade, different transcatheter repair techniques have been developed to treat mitral regurgitation (MR) with less invasive approaches in order to address the unmet clinical need of untreated patients with MR. The aim of this report is to provide an overview of the currently available transcatheter mitral repair options, focusing on the evidence reported so far.

Transcatheter Valve Repair for Patients With Mitral Regurgitation: 30-Day Results of the CLASP Study

OBJECTIVES

The authors report the procedural and 30-day results of the PASCAL Transcatheter Valve Repair System (Edwards Lifesciences, Irvine, California) in patients with mitral regurgitation (MR) enrolled in the multicenter, prospective, single-arm CLASP study.

BACKGROUND

Severe MR may lead to symptoms, impaired quality of life, and reduced functional capacity when untreated.

METHODS

Eligible patients had grade 3+ or 4+ MR despite optimal medical therapy and were deemed appropriate for the study by the local heart team. All outcomes were assessed through 30 days post-procedure. Major adverse events (MAEs) were adjudicated by an independent clinical events committee, and echocardiographic images were assessed by a core laboratory. The primary safety endpoint was the rate of MAEs at 30 days.

RESULTS

Between June 2017 and September 2018, 62 patients with grade 3+ or 4+ MR were enrolled. The mean age was 76.5 years, and 51.6% of patients were in New York Heart Association functional class III or IV, with 56% functional, 36% degenerative, and 8% mixed MR etiology. At 30 days, the MAE rate was 6.5%, with an all-cause mortality rate of 1.6% and no occurrence of stroke; 98% had MR grade ≤2+, with 86% with MR grade ≤1+ (p < 0.0001); and 85% were in New York Heart Association functional class I or II (p < 0.0001). Six-minute walk distance improved by 36 m (p = 0.0018), and Kansas City Cardiomyopathy Questionnaire and EQ-5D scores improved by 17 (p < 0.0001) and 10 (p = 0.0004) points, respectively.

CONCLUSIONS

The PASCAL repair system showed feasibility and acceptable safety in the treatment of patients with grade 3+ or 4+ MR. MR severity, irrespective of etiology, was significantly reduced and accompanied by clinically and statistically significant improvements in functional status, exercise capacity, and quality of life. (The CLASP Study Edwards PASCAL Transcatheter Mitral Valve Repair System Study; NCT03170349).

Transcatheter Mitral Valve Implantation with the Medtronic Intrepid™ Transcatheter Mitral Valve Replacement System

Mitral regurgitation is the most prevalent yet undertreated valvulopathy despite its adverse prognosis. With the emergence of transcatheter mitral interventions, the potential for this huge unmet disease burden to be addressed may finally be realized. Medtronic Intrepid™ Transcatheter Mitral Valve Replacement System represents one of several novel solutions. Based on early data from the pilot study, its efficacy and clinical utility is currently being tested against the mainstay treatment of surgical mitral valve replacement in a randomized trial. While there remain significant challenges before transcatheter mitral intervention can become part of the routine treatment algorithm, the authors are optimistic that transcatheter mitral valve repair and intervention have the potential in revolutionizing the management of severe symptomatic mitral regurgitation.

Safety of centrifugal left ventricular assist device in patients previously treated with MitraClip system

INTRODUCTION

No data regarding the safety of continuous-flow left ventricular assist device (CF-LVAD) implantation in patients with previous MitraClip have been reported. Thus, it remains unknown whether an initial treatment strategy with MitraClip therapy might complicate future heart failure management in patients who are also considered for CF-LVAD.

METHODS

We retrospectively identified 6 patients (median age of 62 years; 2 women) who had been treated with MitraClip, that were eventually implanted with a CF-LVAD (all Heartware HVAD) in 3 hospitals between 2013 and 2018.

RESULTS

Patients were treated in 4 cases with 2 clips, and in 2 cases with 1 clip. Median time from MitraClip implantation to CF-LVAD implant was 282 days (interquartile range 67 to 493), and median time on CF-LVAD support was 401 days (interquartile range 105 to 492 days). Two patients underwent a heart transplant, 3 patients died on support, and 1 is alive on support. In all cases, there was a reduction of functional mitral regurgitation without MitraClip-related complications.

CONCLUSIONS

Based on this small case series, implantation of a CF-LVAD appears safe in patients with a previously positioned MitraClip system, at least, with 1 or 2 clips in place, with no need for additional mitral valve surgery.

Propensity-matched analysis of minimally invasive approach versus sternotomy for mitral valve surgery

OBJECTIVE

The objective of this multicentre study was to compare short-term and midterm outcomes between sternotomy and minimally invasive approaches for mitral valve surgery.

METHODS

Data for all mitral valve procedures with or without concomitant tricuspid atrial fibrillation surgery were analysed from three UK hospitals between January 2008 and December 2016. To account for selection bias between minimally invasive approach and sternotomy, one-to-one propensity score calliper matching without replacement was performed. The main outcome measure was midterm reintervention free survival that was summarised by the Kaplan-Meier estimator and compared between treatment arms using the stratified log-rank test.

RESULTS

A total of 2404 procedures (1757 sternotomy and 647 minimally invasive) were performed during the study period. Propensity score matching resulted in 639 matched pairs with improved balance postmatching in all 31 covariates (absolute standardised mean differences <10%). Despite longer procedural times patients who underwent minimally invasive surgery had a lower need for transfusion (20.5%vs14.4%, p=0.005) and reduced median postoperative length of stay (7 vs 6 days, p<0.001). There were no statistically significant differences in the rates of in-hospital mortality or postoperative stroke. Reintervention-free survival at 8 years was estimated as 86.1% in the minimally invasive group and 84.1% in the sternotomy group (p=0.40).

CONCLUSIONS

Minimally invasive surgery is associated with excellent short-term outcomes and comparable midterm outcomes for patients undergoing mitral valve surgery. A minimally invasive approach should be considered for all patients who require mitral valve intervention and should be the standard against which transcatheter mitral techniques are compared.

Transcatheter interventions for functional mitral regurgitation

Mitral regurgitation is considered the most prevalent valve disease in the United States and its incidence is increasing due to the aging population. Surgical mitral valve repair and replacement are effective at reducing regurgitation due to ischemia, but many patients with secondary mitral regurgitation do not undergo surgery because they are too high risk. Transcatheter devices that mimic surgical techniques are rapidly being developed to reduce the risks traditionally associated with surgical mitral valve repair and replacement. Despite the challenges posed by complex anatomy and multiple etiologies of mitral valve pathology, early results of transcatheter mitral repair and replacement indicate that they have the potential to increase the number of patients with secondary MR who are candidates for intervention.

Contemporary Management of Ischemic Mitral Regurgitation: A Review

Ischemic mitral regurgitation occurs relatively frequently in patients with coronary artery disease and is associated with an increased long-term risk. The pathophysiology of ischemic mitral regurgitation is vexing and poses both diagnostic and therapeutic challenges, leading to the need for a comprehensive, multidisciplinary approach. The management is largely focused on medical therapy, and for those eligible, coronary revascularization or cardiac resynchronization therapy may be considered. In select patients, mitral valve surgery or catheter-based therapy may be undertaken with careful consideration of the underlying pathophysiology, surgical risk, and expected long-term outcomes. The appropriate evaluation of patients with ischemic mitral regurgitation involves a careful multidisciplinary approach that carefully considers symptomatology, the etiology and severity of the mitral regurgitation, and the assessment of comorbidities and operative risk to individualize the care of these patients.

Surgical management of outflow tract obstruction after transapical mitral valve implantation

Left ventricular outflow tract (LVOT) obstruction due to systolic anterior motion of the anterior mitral valve leaflet (AML) is a known complication after mitral valve repair or transfemoral/transapical mitral valve implantation (TMVI). We present a patient with a previous mitral valve repair who developed LVOT obstruction after TMVI in whom the AML was surgically resected using a transaortic approach.

Assessment of the severity of native mitral valve regurgitation

Mitral regurgitation (MR) is a major cause of cardiovascular morbidity and mortality. MR is classified as primary (organic) if it is due to an intrinsic valve abnormality, or secondary (functional) if the etiology is because of remodeling of left ventricular geometry and/or valve annulus. Transthoracic echocardiography (TTE) is the initial modality for MR evaluation. Parameters used for the assessment of MR include valve structure, cardiac remodeling, and color and spectral Doppler. Quantitative measurements include effective regurgitant orifice area, regurgitant volume, and regurgitant fraction. Knowledge of advantages and limitations of echo-Doppler parameters is essential for accurate results. An integrative approach is recommended in overall grading of MR as mild, moderate, or severe since singular parameters may be affected by several factors. When the mechanism and/or grade of MR is unclear from the TTE or is discrepant with the clinical scenario, further evaluation with transesophageal echocardiography or cardiac magnetic resonance imaging is recommended, the latter emerging as a powerful MR quantitation tool.

The changes in pattern of myocardial shortening by reduction of regional coronary blood flow

The relationship between the grade of a decrease in the regional coronary blood flow and the movement of ventricular myocardium of that region was investigated in open chest dog. Blood flow in left anterior descending artery (FLAD) was reduced by stepwise constriction of LAD with ligature. Ventricular segment length was measured in a circumferential plane on the endocardial surface by ultrasonic dimension system. For the elimination of the noise caused by ultrasonic dimension system, the synchronizer was inserted between sample clock of the dimension system and the trigger circuit of the electromagnetic flowmeter. A 20% reduction of FLAD affected the pattern of ischemic myocardial shortening very little. Discontinuance of shortening to the end of systole was occurred by a 20 to 60% reduction in FLAD. Early and/or late systolic bulging was induced by a 60% reduction of FLAD. Systolic bulging with early diastolic shortening was seen in the cases with a 60 to 80% reduction in FLAD. Frank systolic bulging which was always seen by complete occlusion of LAD was produced by a 60 to 90% reduction of FLAD in few cases.