Native Mitral Valve Research Articles

Open transcatheter valve implantation for mitral annular calcification: One-year outcomes.

BackgroundTranscatheter mitral valve implantation (TMVI) for native mitral valve pathology with severe mitral annular calcification has emerged as an alternative treatment option to conventional mitral valve surgery. The objective of this study was to evaluate patients who were referred for TMVI with severe mitral annular calcification and their procedural outcomes.MethodsRetrospective analysis of patients from 2017 to 2020 referred for TMVI was carried out. Demographic characteristic details; surgical strategy; perioperative complications; and hospital stay, including 30-day and 1-year mortality, were analyzed.ResultsEleven patients were referred for consideration of TMVI. The 8 patients who underwent TMVI had a median age of 74 years (range, 57-80 years), the median Society of Thoracic Surgeons score was 4.6 (range, 2.4-10.9), and European System for Cardiac Operative Risk Evaluation II score was 5.2% (2%-10.1%). The median cardiopulmonary bypass time and crossclamp times were 170 minutes (range, 150-248 minutes) and 152 minutes (range, 118-214 minutes), respectively. The median hospital stay was 29 days (range, 2-40 days). Thirty-day in hospital mortality was 12%, whereas 1-year mortality was 25%. There was symptomatic improvement with downgrade of New York Heart Association functional class from III or IV to I or II. The 3 patients who were turned down had a median age of 73 years, median Society of Thoracic Surgeons score was 13.4, and median European System for Cardiac Operative Risk Evaluation II score was 5.72%. They were alive at 12 months follow-up from the date of surgical assessment; however, all with New York Heart Association functional class III or IV symptoms.ConclusionsWe describe a series demonstrating the technical consideration and capability of transatrial TMVI to treat mitral annular calcification and native mitral valve disease. Our results are favorable when compared with TMVI global registry data for transseptal or transapical approach.

Repair of Isolated Native Mitral Valve Endocarditis: A Propensity Matched Study

In the setting of chronic primary mitral regurgitation, the benefit of mitral valve repair over replacement is well established. However, data comparing outcomes for mitral valve surgery for endocarditis is limited. We sought to determine whether mitral valve repair offers traditional advantages over replacement in the endocarditis population. Retrospective review of our institutional mitral valve database (N=8,181) was performed between 1998 and 2019 for all adult patients undergoing isolated mitral valve surgery for endocarditis. Patients were stratified by mitral valve repair or replacement and propensity score matching was performed to adjust for differences in baseline characteristics and degree of valve damage. Overall, 267 surgeries (124 repair, 153 replacement) met inclusion criteria during the study period. Following propensity matching, the repair cohort was associated with shorter initial ventilator times (5.6 vs 7.9 hours, p=0.05), shorter ICU (28 vs 52 hours, p=0.03), and hospital lengths of stays (7 vs 11 days, p < 0.01). Thirty-day mortality (0% vs 2.1%, p=0.01) and 10-year survival (88% vs 86%, p=0.55) were similar between cohorts. Patients in the repair cohort were less likely to require repeat mitral valve intervention at our institution for recurrent endocarditis than those in the replacement cohort (0% vs 10.6%, p=0.03). Mitral valve repair is safe, when feasible, in the setting of isolated native valve endocarditis and may provide patients faster recovery. Experienced mitral surgeons should approach this patient population with a "repair if feasible" methodology.

A Mass in the Left Ventricular Outflow Tract After Mitral Valve Replacement

A 34-year-old woman presented with a four-year history of shortness of breath and dyspnea on exertion that had worsened over the preceding six months. The patient had a stroke two years before her current presentation but had no residual neurologic deficits. Transthoracic 2 two-dimensional echocardiography revealed severe mitral stenosis (peak/mean gradients = 21/14 mmHg), with a mitral valve area of 0.7 cm2 by the pressure-half time method, and calcific thickened mitral valve leaflets with commissural fusion and subvalvular thickening. Pulmonary hypertension was present (right ventricular systolic pressure of 45 mmHg). Left ventricular (LV) ejection fraction was normal (62%). The left atrium (LA) was dilated (60 mm) but LA thrombus was absent. Normal sinus rhythm was present. During surgery, the native mitral valve was replaced with a 25-mm bileaflet mechanical prosthesis. Preservation of both the mitral leaflets and the subvalvular apparatus was carried out. Repeat transesophageal echocardiography (TEE) showed the mechanical prosthesis to be functioning well. In the midesophageal aortic valve (AV) long-and short-axis views, a new mass measuring 8 × 7 mm was seen moving into the aortic root in systole and the left ventricular outflow (LVOT) tract in diastole (Fig. 1, A-C and Video loop 1). Color-flow Doppler did not reveal any systolic flow turbulence (Fig 1, D and Video loop 1). What is the diagnosis?

Left ventricular outflow tract area after percutaneous transseptal transcatheter mitral valve implantation: A three‐dimensional transesophageal echocardiography study

Left ventricular (LV) outflow tract (LVOT) obstruction increases mortality in patients undergoing transcatheter mitral valve implantation (TMVI) in degenerated bioprostheses, annuloplasty rings, and native mitral valves. We aimed to evaluate the LVOT area after TMVI using 3-dimensional (3D) transesophageal echocardiography (TEE) and to investigate the preprocedural cardiac geometry that affects the LVOT area after TMVI. We retrospectively reviewed echocardiography data in 43 patients who had TMVI. A change in pressure gradient across LVOT from before to after TMVI (∆PG) and postprocedure 3D LVOT cross-sectional area at the level of the most distal portion of the mitral valve stent that was closest to the LV apex were assessed as evidence of LVOT narrowing. Transcatheter mitral valve implantation with the use of balloon-expandable valve system was performed for 24 bioprostheses, 7 annuloplasty rings, and 12 native valves. Compared to patients without increase in LVOT gradient (∆PG <10mm Hg; n=33), patients with increase in LVOT gradient (∆PG ≥10mm Hg; n=10) had smaller LV end-systolic volume (LVESV), greater LV ejection fraction (LVEF), and smaller aorto-mitral (AM) angle. The LVOT area at the valve stent distal edge showed strong association with ∆PG (r=-.68, P<.0001). Only a small AM angle was associated with a small LVOT area at the valve stent distal edge on multivariable analysis, independent of LVESV and LVEF. Small LV size, preserved LVEF, and small AM angle were associated with LVOT narrowing. 3D-derived AM angle might be independently associated with LVOT narrowing in patients undergoing transcatheter mitral valve-in-valve, valve-in-ring, and valve-in-native valve implantation, independent of LVESV and LVEF.

Transcatheter Mitral Valve Replacement: Current Evidence and Concepts.

Over the past decade, several transcatheter devices have been developed to address the treatment of severe mitral regurgitation (MR) in patients at high surgical risk, mainly aimed at repairing the native mitral valve (MV). MV repair devices have recently been shown to have high efficacy and safety. However, to replicate promising trial results, specific anatomical and pathophysiological criteria have to be met and operators need a high level of experience. As yet, the longer-term durability of transcatheter MV repair remains unknown. Transcatheter MV replacement (TMVR) might be a treatment option able to target various anatomies, reliably abolish MR, and foster ease of use with a standardised implantation protocol. This review presents upcoming TMVR devices and available data and discusses how TMVR might further advance the field of transcatheter treatment of MR.

Infective endocarditis and outcomes of mitral valve replacement.

We investigated the long-term outcomes of mitral valve replacement (MVR) in native mitral valve infective endocarditis (IE). Multicentre, population-based cohort register study consisted of 1233 consecutive adult patients treated with first-time MVR in Finland. Mitral valve IE was diagnosed in 170 of these patients. Propensity score matching resulted in 134 pairs with balanced baseline characteristics. The median follow-up was 6.1years. Pre-operative native mitral valve IE was associated with an increased hazard of 10-year mortality (38.8% vs 30.5%; HR 2.13; CI 1.17-3.85; P=.013) after MVR. Occurrence of major bleeding was higher in IE patients (26.0%) vs non-IE patients (23.4%) during the 10-year follow-up (HR 2.80; CI 1.01-7.77; P=.048). Hospital admission duration after MVR was longer in IE patients (median 28 vs 11days; P<.0001). Cumulative ischaemic stroke rate was similar between patient groups (12.1% in IE vs 15.1% in non-IE; P=.493). Re-sternotomy was performed in 13.4% of IE patients and 9.0% of non-IE patients (P=.261). Patients with native mitral valve IE have a higher risk of death and major bleeding after MVR than matched patients without IE. Results highlight the importance of complication prevention in these patients.

Large native mitral valve vegetation in a previously healthy 19-year-old woman

A 19-year-old female on a return journey from France to Finland presented with progressive weakness, diffuse limb pain, headache, vomiting and diarrhoea for 3 days. Additionally, she described intermittent periods of impaired vision and fever.

Transcatheter mitral valve interventions: pre-procedural planning and intra-procedural guidance.

Mitral regurgitation is the most prevalent valve disease worldwide. Percutaneous mitral valve interventions are emerging as alternative options for high-risk patients with severe mitral regurgitation not eligible for conventional surgery. Accurate patient selection is based on a detailed pre-procedural multimodality imaging evaluation. Morphology and functional anatomy of the mitral valve should be evaluated to determine the feasibility of treatments and to identify the best therapeutic approach. The procedures are guided by fluoroscopy, transesophageal echocardiography and fusion imaging, ensuring a continuous communication between the interventionalist and the imaging specialist. The present review will cover the pre-procedural planning and the intra-procedural guidance of the most used transcatheter approaches in the setting of native mitral valve regurgitation: edge to edge repair, percutaneous direct and indirect annuloplasty, transapical beating-heart chordal implantation and transcatheter mitral valve replacement.

Fibrin Quantification on Bio-Scaffold Valve Explant as a Measure of Their Integration

Objective: Critical congenital heart valve disease at birth has limited treatment options and can benefit from valves with regenerative capacities. Following a pilot study of porcine small intestinal submucosa (PSIS) bio scaffold mitral valves implanted in a juvenile baboon model, the explanted valves were subsequently quantified for fibrin content or lack thereof, as a measure of valve integration with the host. Methods: PSIS mitral valves were explanted at 3, 11 and 20 month and histologically stained (Movat’s; Alizée Pathology, Inc., Thurmont, MD) and sectioned. Histological images were individually analyzed (ImageJ, NIH, Bethesda, MD), where all images were normalized with respect to the baboon native mitral valve. Following thresholding, the percentage of fibrin area (bright red regions) was computed. Results: Table 1. % Fibrin area on bio-scaffold mitral valve explants Native 3 Month 11 Month 20 Month Percentage Fibrin area 0% 0.10% 1.25% 1.1% Conclusions: Fibrin did not decrease progressively over time. Sustained presence of fibrin at 20-months post-implantation suggests that complete PSIS mitral valve integration was not achieved. This provides motivation for additional scaffold processing (e.g. with stem cells) prior to implantation, to accelerate valve tissue integration with the host.

Approach to Mitral Valve Repair in Infective Endocarditis: Single Center, Single Surgeon, Cross Sectional Study

Objective: The traditional approach was to replace the mitral valve on infective endocarditis when the response to antibiotic therapy is poor. The decision to repair the mitral valve (MV) in this setting is more challenging. This study analysed the different approaches adopted to perform a successful repair. Methods: This retrospective cross sectional study composed of all the patients referred to a single surgeon at Kandy National Hospital, Sri Lanka over a period from June 2011 to August 2020. Repair of MV in every case was the primary approach. Different types of lesion found on direct visual assessment, techniques adopted and outcome of MV repair in native MV infective endocarditis were analysed. Results: Total number of cases was 23, (16 males, 7 females) with a mean age of 42 years. MV repair was successful in all (95%) except one case, as per the intra-operative assessment made (saline test and trans esophageal echocardiography). Vegetation or leaflet perforation were the most common lesions (Posterior mitral valve leaflet/PMVL: 18, Anterior leaflet/AMVL: 7) followed by chordal rupture (6). The table shows the repair strategies used. One death occurred on postoperative third day following MV repair due to rupture of cerebral mycotic aneurysm. 22 patients were discharged home with satisfactory pre-discharge transthoracic 2D echocardiography. Conclusions: The study shows successful repair of MV on infective endocarditis is possible in majority of cases with skilled modulation of surgical approach to individual patient pathology found at the time of surgery. Long term follow-up data requires for the assessment of durability of this approach. Procedure Number Annuloplasty ring (flexible, rigid) 22 Pericardial patchAMVLPMVL 12 Folding plasty 2 Neochords 5 Triangular resection and repairAMVLPMVL 12 Quadrangular resection and repairAMVLPMVL 50 Resection and slidingplastyAMVLPMVL 26

Acute and Short-Term Outcomes of Percutaneous Transcatheter Mitral Valve Replacement in Children.

[Figure: see text].

Incorporating the anterior mitral leaflet to the annulus impairs left ventricular function in an ovine model

ObjectivesTranscatheter mitral valve prostheses are designed to capture the anterior leaflet and surgical techniques designed to fully preserve the subvalvular apparatus at prosthetic valve insertion both serve to shorten the anterior mitral leaflet height, thus effectively incorporating it into the anterior annulus. This study quantifies the acute effects of incorporating the anterior mitral leaflet into the annulus on left ventricular function. MethodsFourteen adult sheep (weight, 48.7 ± 6.2 kg) underwent a mechanical mitral valve insertion on normothermic beating-heart cardiopulmonary bypass, with full retention of the native mitral valve but with placement of exteriorized releasable snares around the anterior mitral leaflet. Continuous measurements of left ventricular mechano-energetics were recorded throughout, alternating incorporating and releasing of the anterior mitral leaflet to the mitral annulus. Echocardiography confirmed the incorporation into the annulus and release. ResultsThe independent indices of left ventricular contractility (ie, end systolic pressure volume relationship and preload recruitable stroke work) were both significantly impaired when the anterior mitral leaflet was incorporated to the annulus and restored after release, as were the hemodynamic parameters: cardiac output, stroke volume, stroke work, and left ventricular pressure decreased by 15%, 17%, 23%, and 11%, respectively. Echocardiography demonstrated increased sphericity of the left ventricle during anterior mitral leaflet incorporation. ConclusionsIncorporating the anterior mitral leaflet to the anterior annulus adversely affected left ventricular contractility, caused distortion of the left ventricle in the form of increased sphericity, and impaired hemodynamic parameters in normal ovine hearts.

Transcatheter Mitral Valve Implantation Systematic Review: Focus on Transseptal Approach and Mitral Annulus Calcification.

This systematic review was performed to evaluate the results of transcatheter mitral valve implantation (TMVI) in the native mitral valve. Medline, EMBASE, and the Cochrane Central register were systematically searched for studies that reported results of TMVI in mitral valve regurgitation and/or stenosis and mitral annular calcification. To improve the sensitivity of the literature search, we performed citation chasing in Google Scholar, Scopus, and Web of Science. Twelve studies reporting results of TMVI in mitral regurgitation were retrieved and included 347 patients. The transseptal approach represented 28% of cases. Secondary mitral regurgitation was the predominant indication in 63% of cases. Thirty-day mortality was 11% and was lowered with the transseptal approach (7%). Technical success was 92%. Surgical conversion was needed in 5% of patients. Only one patient presented moderate to severe mitral regurgitation. These hemodynamic results were sustainable up to one year of follow-up. Three series focused on results of TMVI in mitral annulus calcification including 167 patients. Only nine patients were treated with TMVI dedicated prosthesis. Eighty-seven patients had their prosthesis delivered through a transseptal approach. Mitral stenosis was present in 63% of cases. Thirty-day mortality was 24%, and none with TMVI prosthesis. Technical success was achieved in 71% of cases and was improved by using TMVI prosthesis (89%). The main complication was left ventricular outflow tract obstruction (20%). Post procedural moderate to severe mitral regurgitation was observed in 4% of cases. TMVI seems to be feasible, achieving good technical success and predictable and durable MR reduction.

Annular and subvalvular dynamics after extracellular matrix mitral tube graft implantation in pigs.

Entire mitral valve reconstruction with an extracellular matrix tube graft is a potential candidate to overcome the current limitations of mechanical and bioprosthetic valves. However, clinical data have raised concern with respect to patch failure. The aim of our study was to evaluate the impact of extracellular matrix mitral tube graft implantation on mitral annular and subvalvular regional dynamics in pigs. A modified tube graft design made of 2-ply extracellular matrix was used (CorMatrix®; Cardiovascular Inc., Alpharetta, GA, USA). The reconstructions were performed in an acute 80-kg porcine model (N = 8), where each pig acted as its own control. Haemodynamics were assessed with Mikro-Tip pressure catheters and mitral annular and subvalvular geometry and dynamics with sonomicrometry. Catheter-based peak left atrial pressure and pressure difference across the mitral and aortic valves in the reconstructions were comparable to the values seen in the native mitral valves. Also comparable were maximum mitral annular area (755 ± 100 mm2), maximum septal-lateral distance (29.7 ± 1.7 mm), maximum commissure-commissure distance (35.0 ± 3.4 mm), end-systolic annular height-to-commissural width ratio (10.2 ± 1.0%) and end-diastolic interpapillary muscle distance (27.7 ± 3.3 mm). Systolic expansion of the mitral annulus was, however, observed after reconstruction. The reconstructed mitral valves were fully functional without regurgitation, obstruction or stenosis. The reconstructed mitral annular and subvalvular geometry and subvalvular dynamics were found in the same range to those in the native mitral valve. A regional annular ballooning effect occurred that might predispose to patch failure. However, the greatest risk was found at the papillary muscle attachments.

Temporal outcomes of transcatheter mitral valve replacement in native mitral valve disease with annular calcification.

Surgical intervention in patients with native mitral disease due to severe mitral annular calcification (MAC) carries significant risk. Transcatheter mitral valve replacement (TMVR) using balloon-expandable aortic transcatheter heart valve (THV) in MAC had emerged as alternative treatment. We aim to study the temporal change in clinical outcomes of the procedure at a single center. We retrospectively studied 23 patients who underwent TMVR in MAC at Mayo Clinic from January, 14, 2014 to March, 15, 2019. Cases were divided into early (n= 11) and late (n= 12) experience. The primary end point was 30-day all-cause mortality. The secondary end points were immediate technical success, 30-day procedural success, and 1-year all-cause mortality. Mean age of patients was 75.2 ± 8.9 years and 17 (74.0%) were female. Median STS score for 30-day mortality was 8 (Interquartile range 4.3-13.4) for the entire population. Immediate technical success was achieved in 21 out of 23 patients (two failures in the early experience were related to tamponade and procedural death). Thirty-day procedural success was higher in the late experience (10 out of 12 patients) compared to early experience (5 out of 11 patients, p= .06). Four deaths in the first 30-days were observed in the early experience while all patients survived to hospital discharge in the late experience (p= .01). Procedural success and 30-day survival of transcatheter mitral valve replacement in severe mitral annular calcification procedure using balloon-expandable aortic prosthesis had improved over the years. This is likely attributed to significant advancement in procedural planning, valve design, and techniques.

Current Indications for Transcatheter Mitral Valve Replacement Using Transcatheter Aortic Valves: Valve-in-Valve, Valve-in-Ring, and Valve-in-Mitral Annulus Calcification.

Use of transcatheter mitral valve replacement (TMVR) using transcatheter aortic valves in clinical practice is limited to patients with failing bioprostheses and rings or mitral valve disease associated with severe mitral annulus calcification. Whereas the use of valve-in-valve TMVR appears to be a reasonable alternative to surgery in patients at high surgical risk, much less evidence supports valve-in-ring and valve-in-mitral annulus calcification interventions. Data on the results of TMVR in these settings are derived from small case series or voluntary registries. This review summarizes the current evidence on TMVR using transcatheter aortic valves in clinical practice from the characteristics of the TMVR candidates, screening process, performance of the procedure, and description of current results and future perspectives. TMVR using dedicated devices in native noncalcified mitral valve diseases is beyond the scope of the article.

Left ventricular outflow tract obstruction after transcatheter mitral valve replacement: the importance of preprocedural planning and prevention

Given the prevalence of mitral valve pathology in high-risk patients, transcatheter mitral valve replacement (TMVR) is becoming an attractive treatment modality. A known complication of TMVR is left ventricular outflow tract obstruction (LVOT) due to the prosthetic mitral valve and native anterior mitral valve leaflet encroaching into the LVOT. This is a serious complication which can lead to decreased cardiac output and death. Preprocedural planning with various imaging modalities (multi-detector cardiac CT and echocardiography) can predict those at high risk of LVOT obstruct. To increase awareness and to prevent this complication from occurring in the future, we present a case of LVOT obstruction after TMVR.

Endocarditis on a native mitral valve calcified by irradiation.

Endocarditis on a native mitral valve calcified by irradiation.

Impact of prosthetic mitral valve orientation on the ventricular flow field: Comparison using patient-specific computational fluid dynamics

Significant mitral valve regurgitation creates progressive adverse remodeling of the left ventricle (LV). Replacement of the failing valve with a prosthesis generally improves patient outcomes but leaves the patient with non-physiological intracardiac flow patterns that might contribute to their future risk of thrombus formation and embolism.It has been suggested that the angular orientation of the implanted valve might modify the postoperative distortion of the intraventricular flow field. In this study, we investigated the effect of prosthetic valve orientation on LV flow patterns by using heart geometry from a patient with LV dysfunction and a competent native mitral valve to calculate intracardiac flow fields with computational fluid dynamics (CFD). Results were validated using in vivo 4D Flow MRI. The computed flow fields were compared to calculations following virtual implantation of a mechanical heart valve oriented in four different angles to assess the effect of leaflet position. Flow patterns were visualized in long- and short-axes and quantified with flow component analysis. In comparison to a native valve, valve implantation increased the proportion of the mitral inflow remaining in the basal region and further increased the residual volume in the apical area. Only slight changes due to valve orientation were observed.Using our numerical framework, we demonstrated quantitative changes in left ventricular blood flow due to prosthetic mitral replacement. This framework may be used to improve design of prosthetic heart valves and implantation procedures to minimize the potential for apical flow stasis, and potentially assist personalized treatment planning.

Feasibility and outcome of mitral valve repair in patients with infective endocarditis

BackgroundValve repair is the treatment of choice for native mitral valve regurgitation. The feasibility of repair when the defect is caused by acute infective endocarditis (IE) is debated. This study aims to compare the outcome of repair and replacement procedures, to report the rate of repair in a single surgical center, and to review the literature on this topic.ResultsWe retrospectively analyzed 108 patients with native mitral IE, potentially eligible for surgical repair. Of these 108, 90 (83%) underwent surgery, and 18 were treated conservatively. Among the 90 surgical patients, 57 (63%) underwent valve replacement and 33 valve repair (37%). The mean follow-up duration was 3 years. The two primary endpoints were mortality and freedom from recurrent endocarditis. Secondary endpoints were the post-operative incidence of major adverse events (hospitalization for any cause, pacemaker implantation, new onset of atrial fibrillation, sternal dehiscence), left ventricular systolic function (LVSF), and valvular function at 1-year echocardiographic follow-up. All-cause mortality was lower for valve repair, although not significantly (p = 0.86), as well as nonfatal adverse events (p = 0.92) and relapse rate (p = 0.20) at 3 years. We did not find differences between the two groups at echocardiographic follow-up, neither for left ventricular systolic function (p = 0.22), nor for valvular continence (p = 0.28).ConclusionsIn our experience, the mid-term outcome of repair in IE is comparable to valve replacement and should be considered whenever possible, as in degenerative valve disease. The review of the literature supports this strategy.