Current Status and Future Prospects of Transcatheter Mitral Valve Replacement: JACC State-of-the-Art Review

Mitral regurgitation (MR) is the most prevalent valvular heart disease and, when left untreated, it confers a poorer prognosis. Catheter-based repair therapies face some limitations like their applicability on challenging anatomies and the potential recurrence of significant MR over time. Transcatheter mitral valve replacement (TMVR) has emerged as a less invasive approach potentially overcoming some of the current limitations associated with transcatheter mitral valve repair. Several devices are under clinical investigation, and a growing number of systems allow for a fully percutaneous transfemoral approach. In this review, the authors aimed to delineate the main challenges faced by the TMVR field, to highlight the key aspects for procedural planning, and to describe the clinical results of the TMVR systems under clinical investigation. Finally, they also discuss what the future perspectives are for this emerging field.     

Peri-procedural management of transcatheter mitral valve replacement in patients with heart failure

Over the past decade, transcatheter mitral valve replacement (TMVR) technologies have evolved with the objective of improving outcomes for patients with severe mitral regurgitation (MR) deemed unsuitable for conventional mitral valve surgery. Although the safety and efficacy of transcatheter edge-to-edge mitral valve repair (TEER) is well-established, there is a sense amongst innovators that a major advantage of TMVR may be to offer a more complete solution for the correction of MR in patients whose complex anatomy means that the likelihood of achieving grade 0 or 1 MR with TEER is low. However, abrupt correction of MR in a poorly prepared left ventricle poses a number of unique haemodynamic challenges, particularly when sudden elimination of regurgitant flow causes a relative increase in left ventricular (LV) afterload. Rapid reduction in LV cavity size following MR elimination may itself result in relative LV outflow tract obstruction (LVOTO), irrespective of the intrinsic risk of LVOTO associated with TMVR. Nevertheless, TMVR on a beating heart affords the opportunity to study real-time invasive cardiac indices in high-risk patients with acute reversal of severe MR.     

Combined Tricuspid and Mitral Versus Isolated Mitral Valve Repair for Severe MR and TR: An Analysis From the TriValve and TRAMI Registries

ObjectivesThe aim of this study was to retrospectively compare the characteristics, procedural courses, and outcomes of patients presenting with concomitant mitral regurgitation (MR) and tricuspid regurgitation (TR) in the TriValve (Transcatheter Tricuspid Valve Therapies) and TRAMI (Transcatheter Mitral Valve Interventions) registries.BackgroundTranscatheter mitral edge-to-edge valve repair (TMVR) has been shown to be successful in patients with severe MR. Lately, edge-to-edge repair has also emerged as a possible treatment for severe TR in patients at high risk for cardiac surgery. In patients with both severe MR and TR, the yield of concomitant transcatheter mitral and tricuspid valve repair (TMTVR) for patients at high surgical risk is unknown.MethodsThe characteristics, procedural data, and 1-year outcomes of all patients in the international multicenter TriValve registry and the German multicenter TRAMI registry, who presented with both severe MR and TR, were retrospectively compared. Patients in TRAMI (n = 106) underwent isolated TMVR, while those in TriValve (n = 122) additionally underwent concurrent TMTVR in compassionate and/or off-label use.ResultsAll 228 patients (mean age 77 ± 8 years, 44.3% women) presented with significant dyspnea at baseline (New York Heart Association functional class III or IV in 93.9%), without any differences in the rates of pulmonary hypertension and chronic pulmonary disease. The proportion of patients with left ventricular ejection fraction <30% was higher in the TMVR group (34.9% vs. 18.0%; p < 0.001), while patients in the TMTVR group had lower glomerular filtration rates. At discharge, MR was comparably reduced in both groups. At 1 year, overall all-cause mortality was 34.0% in the TMVR group and 16.4% in the TMTVR group (p = 0.035, Cox regression). On multivariate analysis, TMTVR was associated with a 2-fold lower mortality rate (hazard ratio: 0.52; p = 0.02). The rate of patients in New York Heart Association functional class ≤II at 1 year did not differ (69.4% vs. 67.0%; p = 0.54).ConclusionsConcurrent TMTVR was associated with a higher 1-year survival rate compared with isolated TMVR in patients with both MR and TR. Further randomized trials are needed to confirm these results.     

Transcatheter Mitral Valve Replacement With the Transseptal EVOQUE System

ObjectivesThe aim of this study was to examine the initial experience with a novel transseptal transcatheter mitral valve replacement (TMVR) system.BackgroundTransseptal TMVR may offer a less invasive option than surgery for mitral regurgitation (MR) with greater efficacy and fewer anatomic limitations than transcatheter repair.MethodsPatients were treated with the EVOQUE TMVR system from September 2018 to October 2019. Key inclusion criteria were moderate or greater MR, New York Heart Association functional class ≥II, and high or prohibitive surgical risk. The primary outcome was technical success, defined by Mitral Valve Academic Research Consortium criteria.ResultsFourteen patients were treated, all with at least moderate to severe MR. The median age was 84 years, and the median Society of Thoracic Surgeons score was 4.6%. MR was degenerative in 4 (28.6%), functional in 3 (21.4%), and mixed in 7 (50%). Technical success was achieved in 13 patients (92.9%), and 1 patient was converted to surgery. At 30 days there was 1 noncardiovascular mortality (7.1%), 2 strokes (14.3%), no myocardial infarctions, and no rehospitalizations. Two patients (14.3%) underwent paravalvular leak closure. One patient (7.1%) underwent alcohol septal ablation for left ventricular outflow tract obstruction. Including the 2 patients with paravalvular leak closure, MR was mild or less in all implanted patients at 30 days, with no MR in 10 (83.3%). Mean mitral gradient was 5.8 mm Hg (median). New York Heart Association functional class improved to ≤II in 9 patients (81.8%).ConclusionsThis first-in-human experience has demonstrated the feasibility of the transseptal EVOQUE TMVR system. Further clinical studies are required to establish safety and clinical outcomes.     

Sex-Related Clinical Characteristics and Outcomes of Patients Undergoing Transcatheter Edge-to-Edge Repair for Secondary Mitral Regurgitation

ObjectivesThe authors sought to assess sex-based differences in characteristics and outcomes of patients undergoing transcatheter edge-to-edge mitral valve repair (TMVR) for secondary mitral regurgitation (SMR).BackgroundSubgroup analysis from the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trial indicated potential sex-related differences in outcomes after TMVR. The impact of sex on results after TMVR in a real-world setting is unknown.MethodsThe authors assessed clinical outcomes and echocardiographic parameters in women and men undergoing TMVR for SMR between 2008 and 2018 who were included in the large, international, multicenter real-world EuroSMR registry (European Registry of Transcatheter Repair for Secondary Mitral Regurgitation).ResultsA total of 1,233 patients, including 445 women (36%) and 788 men (64%), were analyzed. Although women were significantly older and had fewer comorbidities than men, TMVR was equally effective in women and men (mitral regurgitation [MR] grade ≤2+ at discharge: 93.2% vs. 94.6% for women vs. men; p = 0.35). All-cause mortality at 1 year (17.9% vs. 18.9%, adjusted hazard ratio: 0.806; p = 0.46) and at 2-year follow-up (26.5% vs. 26.4%, adjusted hazard ratio: 0.757; p = 0.26) were similar in women versus men after multivariate regression analysis. Durability of MR reduction, improvement in symptoms, quality of life, and functional capacity did also not differ during follow-up.ConclusionsResults from the EuroSMR registry confirmed effective and similar MR reduction with TMVR in women and men. There were no sex-related differences in clinical outcomes up to 2 years of follow-up.     

Concomitant Transcatheter Edge-to-Edge Treatment of Secondary Tricuspid and Mitral Regurgitation: An Expert Opinion

Secondary (functional) tricuspid regurgitation (sTR) is common in patients with mitral regurgitation (MR). Because combined valvular heart disease affects long-term survival, in comparison with isolated MR or tricuspid regurgitation, it is essential to offer patients adequate treatment. Despite considerable experience, no conclusive data are yet available on the prognostic impact of concomitant tricuspid valve surgery at the time of mitral valve surgery. Emerging transcatheter treatments offer the opportunity to treat both conditions (MR and sTR) simultaneously or in a stepwise fashion. This review provides a clinical overview on available data regarding the rationale for treatment of sTR in patients with relevant MR undergoing mitral transcatheter edge-to-edge repair, focusing on clinical and anatomical selection criteria.     

Impact of Transcatheter Mitral Valve Repair Availability on Volume and Outcomes of Surgical Repair

BackgroundThe impact of transcatheter edge-to-edge repair (TEER) on national surgical mitral valve repair (MVr) volume and outcomes is unknown.ObjectivesThis study aims to assess the impact of TEER availability on MVr volumes and outcomes for degenerative mitral regurgitation.MethodsMVr volume, 30-day and 5-year outcomes, including mortality, heart failure rehospitalization and mitral valve reintervention, were obtained from the Society of Thoracic Surgeons database linked with Medicare administrative claims and were compared within TEER centers before and after the first institutional TEER procedure. A difference-in-difference approach comparing parallel trends in coronary artery bypass grafting outcomes was used to account for temporal improvements in perioperative care.ResultsFrom July 2011 through December 2018, 13,959 patients underwent MVr at 278 institutions, which became TEER-capable during the study period. There was no significant change in median annualized institutional MVr volume before (32 [IQR: 17-54]) vs after (29 [IQR: 16-54]) the first TEER (P = 0.06). However, higher-risk (Society of Thoracic Surgeons predicted risk of mortality ≥2%) MVr procedures declined over the study period (P < 0.001 for trend). The introduction of TEER was associated with reduced risk-adjusted odds of mortality after MVr at 30 days (adjusted OR: 0.73; 95% CI: 0.54-0.99) and over 5 years (adjusted HR: 0.75; 95% CI: 0.66-0.86). These improvements in 30-day and 5-year mortality were significantly greater than equivalent trends in coronary artery bypass grafting.ConclusionsThe introduction of TEER has not significantly changed overall MVr case volumes for degenerative mitral regurgitation but is associated with a decrease in higher-risk surgical operations and improved 30-day and 5-year outcomes within institutions adopting the technology.     

Machine Learning Identifies Clinical Parameters to Predict Mortality in Patients Undergoing Transcatheter Mitral Valve Repair

ObjectivesThe aim of this study was to develop a machine learning (ML)–based risk stratification tool for 1-year mortality in transcatheter mitral valve repair (TMVR) patients incorporating metabolic and hemodynamic parameters.BackgroundThe lack of appropriate, well-validated, and specific means to risk-stratify patients with mitral regurgitation complicates the evaluation of prognostic benefits of TMVR in clinical trials and practice.MethodsA total of 1,009 TMVR patients from 3 university hospitals within the Heart Failure Network Rhineland were included; 1 hospital (n = 317) served as external validation. The primary endpoint was all-cause 1-year mortality. Model performance was assessed using receiver-operating characteristic curve analysis. In the derivation cohort, different ML algorithms were tested using 5-fold cross-validation. The final model, called MITRALITY (transcatheter mitral valve repair mortality prediction system) was tested in the validation cohort with respect to existing clinical scores.ResultsExtreme gradient boosting was selected for the MITRALITY score, using only 6 baseline clinical features for prediction (in order of predictive importance): urea, hemoglobin, N-terminal pro–brain natriuretic peptide, mean arterial pressure, body mass index, and creatinine. In the external validation cohort, the MITRALITY score’s area under the curve was 0.783 (95% CI: 0.716-0.849), while existing scores yielded areas under the curve of 0.721 (95% CI: 0.63-0.811) and 0.657 (95% CI: 0.536-0.778) at best.ConclusionsThe MITRALITY score is a novel, internally and externally validated ML-based tool for risk stratification of patients prior to TMVR, potentially serving future clinical trials and daily clinical practice.     

Alcohol Septal Ablation to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement: First-in-Man Study

ObjectivesThis study evaluates outcomes of pre-emptive alcohol septal ablation (ASA) to prevent iatrogenic left ventricular outflow tract (LVOT) obstruction after transcatheter mitral valve replacement (TMVR).BackgroundLVOT obstruction is a life-threatening complication of TMVR. Bail-out ASA has been described as a therapeutic option for patients with outflow obstruction during TMVR, but little is known about pre-emptive ASA.MethodsMulticenter registry of patients with severe mitral valve disease who underwent pre-emptive ASA to mitigate LVOT obstruction risk after TMVR. High risk of LVOT obstruction was predicted in all patients by pre-procedural computed tomographic imaging.ResultsThirty patients (age 76.1 ± 7.7 years; women 76.7%) with severe mitral valve disease underwent pre-emptive ASA to mitigate TMVR-induced LVOT obstruction risk. Twenty patients underwent mitral valve replacement (14 transseptal, 3 transatrial, 1 transapical, 1 transseptal with percutaneous laceration of anterior mitral leaflet, 1 treated with surgical mitral valve replacement). Eight patients experienced clinical improvement post-ASA. Two patients died before TMVR. Median increase in neo-LVOT surface area post-ASA was 111.2 mm² (interquartile range: 71.4 to 193.1 mm²). Five patients (16.7%) required pacemaker implantation post-ASA. In-hospital and 30-day mortality post-ASA was 6.7% (2/30 patients). After ASA, TMVR was performed successfully in 100% of attempted cases. In-hospital and 30-day mortality post-TMVR was 5.3% (1/19). Mortality of entire cohort was 10% (3/30 patients: 2 post-ASA before TMVR, 1 died 30 days post-TMVR).ConclusionsPre-emptive ASA is associated with a significant increase in predicted neo-LVOT area before TMVR and may enable safe TMVR in patients usually excluded secondary to prohibitive risk of LVOT obstruction.     

Impact of Residual Mitral Regurgitation on Survival After Transcatheter Edge-to-Edge Repair for Secondary Mitral Regurgitation

ObjectivesThe aim of this study was to assess the impact of residual mitral regurgitation (resMR) on mortality with respect to left ventricular dilatation (LV-Dil) or right ventricular dysfunction (RV-Dys) in patients with secondary mitral regurgitation (SMR) who underwent mitral valve transcatheter edge-to-edge repair (TEER).BackgroundThe presence of LV-Dil and RV-Dys correlates with advanced stages of heart failure in SMR patients, which may impact the outcome after TEER.MethodsSMR patients in a European multicenter registry were evaluated. Investigated outcomes were 2-year all-cause mortality and improvement in New York Heart Association functional class with respect to MR reduction, LV-Dil (defined as LV end-diastolic volume ≥159 ml), and RV-Dys (defined as tricuspid annular plane systolic excursion-to-systolic pulmonary artery pressure ratio of <0.274 mm/mm Hg).ResultsAmong 809 included patients, resMR ≤1+ was achieved in 546 (67%) patients. Overall estimated 2-year mortality rate was 32%. Post-procedural resMR was significantly associated with mortality (p = 0.031). Although the improvement in New York Heart Association functional class persisted regardless of either LV-Dil or RV-Dys, the beneficial treatment effect of resMR ≤1+ on 2-year mortality was observed only in patients without LV-Dil and RV-Dys (hazard ratio: 1.75; 95% confidence interval: 1.03 to 3.00).ConclusionsAchieving optimal MR reduction by TEER is associated with improved survival in SMR patients, especially if the progress in heart failure is not too advanced. In SMR patients with advanced stages of heart failure, as evidenced by LV-Dil or RV-Dys, the treatment effect of TEER on symptomatic improvement is maintained, but the survival benefit appears to be reduced.     

Transcatheter Edge-to-Edge Repair for Atrial Secondary Mitral Regurgitation

BackgroundAtrial secondary mitral regurgitation (ASMR) is a subtype of SMR that has a poor prognosis, and thus far, evidence of the therapeutic options for the management of ASMR is limited.ObjectivesThis study aimed to investigate the effectiveness of transcatheter edge-to-edge repair (TEER) for ASMR.MethodsThe study retrospectively analyzed consecutive patients who underwent MitraClip at the Heart Center Bonn. ASMR was defined as cases that met all of the following criteria: 1) normal mitral leaflets without organic disorder; 2) left ventricular ejection fraction >50%; and 3) absence of LV enlargement and segmental abnormality. The primary outcome measure was MR reduction to ≤1+, and its predictors were explored in a logistic regression analysis.ResultsAmong 415 patients with SMR, 118 patients met the criteria for ASMR (mean age 80 ± 8 years, 39.8% male). The technical success rate was 94.1%, and MR reduction to ≤1+ after TEER was achieved in 94 (79.7%) patients with ASMR. The in-hospital mortality rate was 2.5%. In multivariable logistic analysis, a large left atrial volume index and low leaflet-to-annulus index were associated with a lower incidence of MR reduction to ≤1+ after TEER for ASMR. In addition, the use of a newer generation of the MitraClip systems (NTR/XTR or G4 systems) was associated with a higher incidence of MR reduction to ≤1+.ConclusionsTEER is a safe and feasible therapeutic option for patients with ASMR. Assessments of left atrial volume index and leaflet-to-annulus index may assist with patient selection for TEER in patients with ASMR.     

Transcatheter Mitral Valve Replacement: An Update on Current Techniques,Technologies, and Future Directions

Growing clinical data support the use of transcatheter therapies for significant mitral valve disease. Currently, edge-to-edge repair is the transcatheter treatment of choice, but many anatomies are not suitable. Transcatheter mitral valve replacement offers several potential advantages over transcatheter repair, most notably a greater and more sustained reduction in mitral regurgitation post-implantation, but also potential disadvantages. To enable the successful treatment of mitral valve disease in a wide range of patients and anatomies, we require an armory of transcatheter devices, including transcatheter mitral valve replacement systems.     

Multiphase Assessment of Mitral Annular Dynamics in Consecutive Patients With Significant Mitral Valve Disease

ObjectivesThe aim of this study was to clarify the dynamics of the mitral annulus throughout the cardiac cycle and its relevance to transcatheter mitral valve replacement (TMVR) sizing and case selection.BackgroundLimited data are available regarding the relevance of mitral annular (MA) and neo–left ventricular outflow tract (LVOT) dynamics in the overall population presenting with significant mitral valve disease.MethodsPatients attending a combined surgical-transcatheter heart valve clinic for severe symptomatic mitral valve disease were assessed using multiphase computed tomography. The relative influence of MA and neo-LVOT dynamics to TMVR case selection was studied.ResultsA total of 476 patients with significant mitral valve disease were evaluated. In 99 consecutive patients with severe mitral regurgitation, a 10-phase assessment showed that the mitral annulus was on average largest in late systole. On comparing maximal MA dimension with late systolic dimension, TMVR size assignment changed in 24.2% of patients. If the average MA perimeter was used to determine sizing, 48.5% were excluded because of MA dimension being too large; in a multiphase assessment of the neo-LVOT, an additional 16.2% were excluded on the basis of neo-LVOT dimension. In an expanded series of 312 consecutive patients, selection protocol influenced anatomical exclusion: a manufacturer-proposed early systolic approach excluded 69.2% of patients, whereas a late systolic approach excluded 82.7% of patients, the vast majority because of large mitral annuli.ConclusionsContemporary TMVR can treat only a minority of patients with severe mitral regurgitation, principally because of limitations of large MA dimension.     

Long-Term Outcomes of Patients With Elevated Mitral Valve Pressure Gradient After Mitral Valve Edge-to-Edge Repair

ObjectivesThe aim of this study was to investigate the adverse impact of elevated postprocedural mitral valve pressure gradient (MPG) on outcome in a real-world population of patients with severe mitral regurgitation (MR) who underwent transcatheter mitral valve edge-to-edge repair (TEER).BackgroundTEER has become a routine treatment alternative for patients with severe MR at high surgical risk. The consequences of elevated MPG after TEER have been subject to controversial debates.MethodsAll consecutive patients undergoing TEER for either severe degenerative MR (DMR) or functional MR (FMR) at a high-volume center between September 2008 and January 2020 were prospectively included and followed periodically. Postprocedural MPG by discharge transthoracic echocardiography was considered elevated at ≥5 mm Hg. The primary combined endpoint was death or heart failure rehospitalization after 5 years.ResultsA total of 713 patients undergoing TEER (DMR, n = 265; FMR, n = 445) were included. Elevated postprocedural MPG was present in 37.0% of those with DMR (n = 98) and 22.0% of those with FMR (n = 98). In contrast to patients with FMR, 6-minute walk distance did not improve in patients with DMR with elevated MPG. Kaplan-Meier analyses did not demonstrate significant differences for the primary endpoint in patients with DMR (low vs elevated MPG, 67.3% vs 74.4%; P = 0.06) and those with FMR (78.6% vs 74.8%; P = 0.54). After adjustment, elevated MPG was an independent predictor of the primary endpoint in patients with DMR (HR: 1.59; 95% CI: 1.03-2.45; P = 0.034) but not in those with FMR (HR: 0.87; 95% CI: 0.63-1.22; P = 0.43).ConclusionsElevated postprocedural MPG is an independent predictor of adverse clinical and functional outcomes in patients with DMR but not in those with FMR     

Prognostic Value of Increased Mitral Valve Gradient After Transcatheter Edge-to-Edge Repair for Primary Mitral Regurgitation

ObjectivesThis study sought to evaluate the prognostic value of an increased mean mitral valve pressure gradient (MVG) in patients with primary mitral regurgitation (MR) after transcatheter edge-to-edge repair (TEER).BackgroundConflicting data exist regarding impact of increased mean MVG on outcomes after TEER.MethodsThis study included 419 patients with primary MR (mean age 80.6 ± 10.4 years; 40.6% female) who underwent TEER. Patients were divided into quartiles (Qs) based on discharge echocardiographic mean MVG. Primary outcome was the composite endpoint of all-cause mortality and heart failure hospitalization. Secondary outcomes included all-cause mortality and the secondary composite endpoint of all-cause mortality, heart failure hospitalization, and mitral valve reintervention.ResultsThe median number of MitraClips used was 2 per patient. MR reduction ≤moderate was achieved in 407 (97.1%) patients. Mean MVG was 1.9 ± 0.3 mm Hg, 3.0 ± 0.1 mm Hg, 4.0 ± 0.1 mm Hg, and 6.0 ± 1.2 mm Hg in Q1, Q2, Q3, and Q4, respectively. There was no significant differences across quartiles in the primary outcome (15.4%, 19.6%, 22.0%, and 21.9% in Q1-Q4, respectively; P = 0.63), all-cause mortality (15.9% vs 18.6% vs 19.4% vs 17.1%, respectively; P = 0.91), and the secondary composite endpoint at 2 years (33.3% vs 29.5% vs 22.0% vs 31.6%, respectively; P = 0.37). After multivariate adjustment for baseline clinical and procedural variables, the mean MVG in Q4 compared with Q1 to Q3 was not independently associated with the primary outcome (HR: 1.22; 95% CI: 0.82-1.83; P = 0.33), all-cause mortality, and the secondary composite endpoint.ConclusionsIncreased mean MVG was not independently associated with adverse events after TEER in patients with primary MR.     

Tip-to-Base LAMPOON for Transcatheter Mitral Valve Replacement With a Protected Mitral Annulus

ObjectivesThe purpose of this study was to evaluate tip-to-base intentional laceration of the anterior mitral leaflet to prevent left ventricular outflow tract obstruction (LAMPOON) in patients undergoing transcatheter mitral valve replacement (TMVR) in annuloplasty rings or surgical mitral valves.BackgroundLAMPOON is an effective adjunct to TMVR that prevents left ventricular outflow tract obstruction (LVOTO). Laceration is typically performed from the base to the tip of the anterior mitral leaflet. A modified laceration technique from leaflet tip to base may be effective in patients with a prosthesis that protects the aortomitral curtain.MethodsThis is a multicenter, 21-patient, consecutive retrospective observational cohort. Patients underwent tip-to-base LAMPOON to prevent LVOTO and leaflet overhang, or therapeutically to lacerate a long anterior mitral leaflet risking or causing LVOTO. Outcomes were compared with findings from patients in the LAMPOON investigational device exemption trial with a prior mitral annuloplasty.ResultsTwenty-one patients with a annuloplasty or valve prosthesis–protected mitral annulus underwent tip-to-base LAMPOON (19 preventive, 2 rescue). Leaflet laceration was successful in all and successfully prevented or treated LVOTO in all patients. No patients had significant LVOTO upon discharge. There were 2 cases of unintentional aortic valve injury (1 patient underwent emergency transcatheter aortic valve replacement and 1 patient underwent urgent surgical aortic valve replacement). In both cases, the patients had a supra-annular ring annuloplasty, and the retrograde aortic guiding catheter failed to insulate the guidewire lacerating surface from the aortic root. All patients survived to 30 days. Compared with classic retrograde LAMPOON, there was a trend toward shorter procedure time.ConclusionsTip-to-base laceration is a simple, effective, and safe LAMPOON variant applicable to patients with an appropriately positioned mitral annular ring or bioprosthetic valve. Operators should take care to insulate the lacerating surface from adjacent structures.     

Mitral Valve Surgery After Transcatheter Edge-to-Edge Repair: Mid-Term Outcomes From the CUTTING-EDGE International Registry

ObjectivesThe aim of this study was to determine clinical and echocardiographic characteristics, mechanisms of failure, and outcomes of mitral valve (MV) surgery after transcatheter edge-to-edge repair (TEER).BackgroundAlthough >100,000 mitral TEER procedures have been performed worldwide, longitudinal data on MV surgery after TEER are lacking.MethodsData from the multicenter, international CUTTING-EDGE registry were retrospectively analyzed. Clinical and echocardiographic outcomes were evaluated. Median follow-up duration was 9.0 months (interquartile range [IQR]: 1.2-25.7 months) after MV surgery, and follow-up was 96.1% complete at 30 days and 81.1% complete at 1 year.ResultsFrom July 2009 to July 2020, 332 patients across 34 centers underwent MV surgery after TEER. The mean age was 73.8 ± 10.1 years, median Society of Thoracic Surgeons risk for MV repair at initial TEER was 4.0 (IQR: 2.3-7.3), and primary/mixed and secondary mitral regurgitation were present in 59.0% and 38.5%, respectively. The median interval from TEER to surgery was 3.5 months (IQR: 0.5-11.9 months), with overall median Society of Thoracic Surgeons risk of 4.8% for MV replacement (IQR: 2.8%-8.4%). The primary indication for surgery was recurrent mitral regurgitation (33.5%), and MV replacement and concomitant tricuspid surgery were performed in 92.5% and 42.2% of patients, respectively. The 30-day and 1-year mortality rates were 16.6% and 31.3%, respectively. On Kaplan-Meier analysis, the actuarial estimates of mortality were 24.1% at 1 year and 31.7% at 3 years after MV surgery.ConclusionsIn this first report of the CUTTING-EDGE registry, the mortality and morbidity risks of MV surgery after TEER were not negligible, and only <10% of patients underwent MV repair. These registry data provide valuable insights for further research to improve these outcomes.     

Clinical Outcomes With Transcatheter Edge-to-Edge Repair in Atrial Functional MR From the EXPAND Study

BackgroundAlthough transcatheter edge-to-edge repair (TEER) has been shown to improve clinical outcomes and improve quality of life in patients with symptomatic secondary mitral regurgitation (SMR) and left ventricular dysfunction, its effect in patients with atrial SMR (aSMR) has not been well described.ObjectivesThe aim of this study was to assess the safety, echocardiographic outcomes, and clinical effectiveness of TEER for aSMR.MethodsPatients with aSMR in the prospective, observational, multicenter EXPAND (A Contemporary, Prospective, Multi-Center Study Evaluating Real-World Experience of Performance and Safety for the Next Generation of MitraClip Devices) study were identified by an echocardiography core laboratory. Follow-up occurred at discharge, 30 days, and 1 year. Key endpoints included mitral regurgitation (MR) severity, functional class, heart failure hospitalizations, mortality, and 30-day major adverse events.ResultsAmong 1,041 patients enrolled in EXPAND, 835 patients had evaluable echocardiograms at baseline. Of these, 53 patients had aSMR and 360 had ventricular SMR (vSMR). In the aSMR cohort, TEER resulted in a significant reduction in MR through 1 year (MR grade ≤2 in 100.0%), significantly increased 1-year Kansas City Cardiomyopathy Questionnaire score (+26.6 ± 30.5 points; P < 0.0001), and improved functional class from baseline, similar to the effects among patients with vSMR (MR grade ≤2 in 99.5% at 1 year, 1-year increase in Kansas City Cardiomyopathy Questionnaire score 21.23 ± 24.92 points). Major adverse events at 30 days and leaflet adverse events at 1 year were infrequent in both groups.ConclusionsIn a prospective, real-world, global registry, TEER for aSMR was associated with significant MR reduction and improvement in quality of life and functional class, similar to patients with vSMR. This suggests that TEER may provide clinical benefit in patients with atrial fibrillation with SMR in the setting of heart failure with preserved ejection fraction. (The MitraClip® EXPAND Study of the Next Generation of MitraClip® Devices; NCT03502811)     

Institutional Experience With Transcatheter Mitral Valve Repair and Clinical Outcomes: Insights From the TVT Registry

ObjectivesThe aim of this study was to examine the relation between institutional experience and procedural results of transcatheter mitral valve repair.BackgroundTranscatheter mitral valve repair for the treatment of mitral regurgitation (MR) is a complex procedure requiring navigation of the left atrium, left ventricle, and mitral valve apparatus using echocardiographic guidance.MethodsMitraClip procedures from the Society of Thoracic Surgeons/American College of Cardiology TVT (Transcatheter Valve Therapy) Registry were stratified into tertiles on the basis of site-specific case sequence (1 to 18, 19 to 51, and 52 to 482). In-hospital outcomes of procedural success, procedural time, and procedural complications were examined. To evaluate the learning curve for the procedure, generalized linear mixed models were developed using case sequence number as a continuous variable.ResultsMitraClip procedures (n = 12,334) performed at 275 sites between November 2013 and September 2017 were analyzed. Optimal procedural success (≤1+ residual MR without mortality or need for cardiac surgery) increased across tertiles of case experience (62.0%, 65.5%, and 72.5%; p < 0.001), whereas procedural time and procedural complications decreased. Acceptable procedural success (≤2+ residual MR without death or need for cardiac surgery) also increased across tertiles of case experience, but the differences were smaller (91.2%, 91.2%; and 92.9%; p = 0.006). In the learning-curve analysis, visual inflection points for procedural time, procedural success, and procedural complications were evident after about 50 cases, with continued improvements observed up to 200 cases.ConclusionsFor transcatheter mitral valve repair with the MitraClip, increasing institutional experience was associated with improvements in procedural success, procedure time, and procedural complications. The impact of institutional experience was larger when considering the goal of achieving optimal MR reduction.     

Anterior Leaflet Laceration to Prevent Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Replacement

BackgroundLeft ventricular outflow tract (LVOT) obstruction is a leading cause of mortality and exclusion from transcatheter mitral valve replacement (TMVR). Intentional laceration of the anterior mitral valve leaflet to prevent LVOT obstruction (LAMPOON) is a transcatheter mimic of surgical chord-sparing leaflet resection.ObjectivesThe purpose of this prospective multicenter trial was to study LAMPOON with transseptal (Edwards Lifesciences, Irvine, California) TMVR in annuloplasty rings or native mitral annular calcification (MAC).MethodsSubjects at high or extreme surgical risk and prohibitive risk of LVOT obstruction from TMVR were included. Eligibility was modified midtrial to exclude subjects with threatened LVOT obstruction from a Sapien 3 valve fabric skirt. The primary endpoint was procedure survival with successful LAMPOON, with successful TMVR, without reintervention, and with LVOT gradient <30 mm Hg (“optimal”) or <50 mm Hg (“acceptable”). Secondary endpoints included 30-day mortality and major adverse cardiovascular events. There was universal source-data verification and independent monitoring. All endpoints were independently adjudicated. Central laboratories analyzed echocardiogram and CT images.ResultsBetween June 2017 and June 2018, 30 subjects were enrolled equally between the MAC and ring arms. LAMPOON traversal and midline laceration was successful in 100%. Procedure survival was 100%, and 30-day survival was 93%. Primary success was achieved in 73%, driven by additional procedures for paravalvular leak (10%) and high-skirt neo-LVOT gradients observed before a protocol amendment. There were no strokes.ConclusionsLAMPOON was feasible in native and annuloplasty ring anatomies in patients who were otherwise ineligible for treatment, with acceptable safety. LAMPOON was effective in preventing LVOT obstruction from TMVR. Despite LAMPOON, TMVR using Sapien 3 in annuloplasty rings and MAC still exhibits important limitations. (NHLBI DIR LAMPOON Study: Intentional Laceration of the Anterior Mitral Leaflet to Prevent Left Ventricular Outflow Tract Obstruction During Transcatheter Mitral Valve Implantation; NCT03015194)