Is repair preferable to replacement for ischemic mitral regurgitation?

Multimodality imaging assessment of mitral valve anatomy in planning for mitral valve repair in secondary mitral regurgitation

Secondary mitral regurgitation (MR) is frequent valvular heart disease and conveys worse prognostic. Therapeutic surgical or percutaneous options are available in the context of severe symptomatic secondary MR, but the best approach to treat these patients remains unclear, given the lack of clear clinical evidence of benefit. A comprehensive evaluation of the mitral valve apparatus and the left ventricle (LV) has the ability to clearly define and characterize the disease, and thus determine the best option for the patient to improve its clinical outcomes, as well as quality of life and symptoms. The current report reviews the mitral valve (MV) anatomy, the underlying mechanisms associated with secondary MR, the related therapeutic options available, and finally the usefulness of a multimodality imaging approach for the planning of surgical or percutaneous mitral valve intervention.

Ex Vivo Methods for Informing Computational Models of the Mitral Valve

Computational modeling of the mitral valve (MV) has potential applications for determining optimal MV repair techniques and risk of recurrent mitral regurgitation. Two key concerns for informing these models are (1) sensitivity of model performance to the accuracy of the input geometry, and, (2) acquisition of comprehensive data sets against which the simulation can be validated across clinically relevant geometries. Addressing the first concern, ex vivo micro-computed tomography (microCT) was used to image MVs at high resolution (~40 micron voxel size). Because MVs distorted substantially during static imaging, glutaraldehyde fixation was used prior to microCT. After fixation, MV leaflet distortions were significantly smaller (p < 0.005), and detail of the chordal tree was appreciably greater. Addressing the second concern, a left heart simulator was designed to reproduce MV geometric perturbations seen in vivo in functional mitral regurgitation and after subsequent repair, and maintain compatibility with microCT. By permuting individual excised ovine MVs (n = 5) through each state (healthy, diseased and repaired), and imaging with microCT in each state, a comprehensive data set was produced. Using this data set, work is ongoing to construct and validate high-fidelity MV biomechanical models. These models will seek to link MV function across clinically relevant states.

Ischemic mitral valve prolapse

Ischemic mitral prolapse (IMP) is a pathologic entity encountered in about one-third among the patients undergoing surgery for ischemic mitral regurgitation (IMR). IMP is generally the result of a papillary muscle injury consequent to myocardial, but the recent literature is progressively unveiling a more complex pathogenesis. The mechanisms underlying its development regards the impairment of one or more components of the mitral apparatus, which comprises the annulus, the chordae tendineae, the papillary muscle and the left ventricular wall. IMP is not only a disorder of valvular function, but also entails coexistent aspects of a geometric disturbance of the mitral valve configuration and of the left ventricular function and dimension and a correct understanding of all these aspects is crucial to guide and tailor the correct therapeutic strategy to be adopted. Localization of prolapse, anatomic features of the prolapsed leaflets and the subvalvular apparatus should be carefully evaluated as also constituting the major determinants defining patient's outcomes. This review will summarize our current understanding of the pathophysiology and clinical evidence on IMP with a particular focus on the surgical treatment.

Mid-term results of mitral valve repair for ischemic mitral regurgitation with ETlogix ring: A single-center study

BACKGROUND

Ischemic mitral regurgitation (IMR) is a common complication of coronary artery disease and represents an independent predictor of mortality. In the IMR the pattern of mitral valve annular dilatation is asymmetrical: this can explain the long-term incidence of recurrent mitral regurgitation after surgical annular size reduction with a symmetrical ring. The aim of this study is to analyze early and mid-term results of mitral valve repair (MVR) with the CMA IMR ETlogix ring, specifically developed for the surgical correction of IMR.

METHODS

Retrospectively, we studied 157 consecutive patients who underwent MVR with the CMA ETlogix ring for the treatment of grade ≥2 IMR in our center between June 2006 and December 2012. We reported clinical and echocardiographic early and mid-term results of this surgical technique.

RESULTS

Postoperative 30days mortality was 6.3%. Postoperative echocardiography evaluation at discharge revealed the absence of residual MR in 70%, mild MR in 26.5% and moderate MR in 3.5% of patients respectively. Median echographic follow-up time was 28 (3-84) months: survival rate was 92.1% at 32months; free from mitral valve reoperation rate was 97.5% and grade >2 MR recurrence free survival rate was 96.6%.

CONCLUSION

There are a few reports in the literature concerning the mid-term results of IMR surgical correction with CMA Etlogix ring. Our study, taking into account a large series of patients and an important follow-up period, demonstrates the effectiveness of this surgical repair technique reporting a low mid-term incidence of recurrent MR.

The Course of Ischemic Mitral Regurgitation in Acute Myocardial Infarction After Primary Percutaneous Coronary Intervention

Background—

Previously published evidence on ischemic mitral regurgitation (IMR) and its adverse prognosis after myocardial infarction has been based on the severity of IMR in the subacute or chronic period of myocardial infarction. However, the state of IMR can vary from the early stage to the chronic stage as a result of various responses of myocardium after primary percutaneous coronary intervention (PCI).

Methods and Results—

Standard echocardiography was serially performed in 546 consecutive patients with first-onset acute myocardial infarction (1) immediately after their arrival (pre-PCI), (2) before discharge (early post-PCI), and (3) 6 to 8 months after PCI (late post-PCI). The course of IMR after primary PCI and the prognostic impact of the IMR in each phase were investigated. IMR was found in 193/546 (35%) patients at the emergency room. In the acute phase after PCI, IMR improved in 63 patients. IMR worsened in 78 patients despite successful PCI. Shorter onset-to-reperfusion time and nontotal occlusion before PCI were the independent predictors of early improvement of IMR. In the chronic phase, IMR improved in 79 patients and worsened in 36 patients. Lower peak creatine kinase–myocardial band was an independent predictor of late improvement of IMR. IMR before PCI worsened 30-day prognosis ( P =0.02), and persistent IMR in the chronic phase worsened long-term prognosis ( P =0.04) after primary PCI.

Conclusions—

Degrees of IMR changed in the early and chronic phase after primary PCI for acute myocardial infarction. IMR on arrival and persistent IMR in the chronic phase worsened short-term and long-term prognosis after acute myocardial infarction, respectively.

The value of preoperative 3-dimensional over 2-dimensional valve analysis in predicting recurrent ischemic mitral regurgitation after mitral annuloplasty

OBJECTIVES

Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.

METHODS

Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation. Two-dimensional echocardiography annular diameter and tethering parameters were measured in the apical 2- and 4-chamber views. A customized protocol was used to assess 3-dimensional annular geometry and regional leaflet tethering. Recurrence (grade ≥2) was assessed with 2-dimensional transthoracic echocardiography at 6 months.

RESULTS

Preoperative 2- and 3-dimensional annular geometry were similar in all patients with ischemic mitral regurgitation. Preoperative 2- and 3-dimensional leaflet tethering were significantly higher in patients with recurrence (n = 13) when compared with patients without recurrence (n = 37). Multivariate logistic regression revealed preoperative 2-dimensional echocardiography posterior tethering angle as an independent predictor of recurrence with an optimal cutoff value of 32.0° (area under the curve, 0.81; 95% confidence interval, 0.68-0.95; P = .002) and preoperative 3-dimensional echocardiography P3 tethering angle as an independent predictor of recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84-1.00; P < .001). The predictive value of the 3-dimensional geometric multivariate model can be augmented by adding basal aneurysm/dyskinesis (area under the curve, 0.94; 95% confidence interval, 0.87-1.00; P < .001).

CONCLUSIONS

Preoperative 3-dimensional echocardiography P3 tethering angle is a stronger predictor of ischemic mitral regurgitation recurrence after annuloplasty than preoperative 2-dimensional echocardiography posterior tethering angle, which is highly influenced by viewing plane. In patients with a preoperative P3 tethering angle of 29.9° or larger (especially when combined with basal aneurysm/dyskinesis), chordal-sparing valve replacement should be strongly considered.

Is valve repair preferable to valve replacement in ischaemic mitral regurgitation? A systematic review and meta-analysis

Ischaemic mitral regurgitation (MR) is associated with poor survival. The favoured surgical option remains debatable. Our aim was to perform a meta-analysis to compare the outcomes of mitral valve repair (MVRp) with replacement (MVR). A literature search was conducted in PubMed, Medline and Ovid using the terms 'ischaemic mitral regurgitation', 'repair' and 'replacement'. The primary outcome measure was 30-day survival. The secondary outcome measures were MR recurrence and reoperation. Out of 310 articles, 18 fulfilled the inclusion criteria. A total of 3978 patients were included: 2563 (64%) MVRp cases and 1415 (36%) MVR cases. Operative techniques included annuloplasty for MVRp and subvalvular apparatus-sparing MVR techniques. Thirty-day mortality was lower after MVRp compared with MVR [OR 0.42; (95% CI 0.33-0.54; P = 0.0001)]. There was no difference in long-term survival ranging 1-5 years (HR 0.85, 95% CI 0.65-1.12). Recurrence of MR was significantly higher in the MVRp group (OR 4.26, 95% CI 2.52-7.22), as was the rate of reoperation (OR 2.03, 95% CI 1.49-2.77). Although MVR for ischaemic MR has a higher 30-day mortality rate compared with MVRp, MVRp is associated with the higher rate of MR recurrence and the need for reoperation. MVR remains an attractive option for ischaemic MR.

Prevalence of severe mitral regurgitation eligible for edge-to-edge mitral valve repair (MitraClip)

OBJECTIVES

We assessed the prevalence of moderately severe or severe mitral regurgitation (MR) justifying edge-to-edge mitral valve (MV) repair (MitraClip(®)) in patients attending the University Hospital Wuerzburg, a tertiary care centre located in Wuerzburg, Germany.

BACKGROUND

Transcatheter edge-to-edge MV repair of advanced MR is a non-surgical treatment option in inoperable and high-risk patients. It is unknown how many patients are potentially eligible for MitraClip(®) since several anatomical prerequisites of the MV apparatus have to be met for optimal treatment results.

METHODS

Using a novel clinical data warehouse we searched for all patients attached to our Department of Internal Medicine from 01/2008 to 01/2012 with moderately severe or severe MR and aged ≥18 years. The current status of their treatment regime and eligibility for MitraClip(®) was assessed and re-evaluated according to current guidelines and echocardiographic criteria.

RESULTS

The search of electronic medical records amongst 43,690 patients employed an innovative validated text extraction method and identified 331 patients with moderately severe or severe MR who had undergone echocardiographic assessment at our institution. Of these, 125 (38 %) received MV surgery and 206 (62 %) medical therapy only. Most patients not undergoing surgery had secondary MR (70 %). After evaluation of medical and echocardiographic data of medically treated patients (n = 206), 81 (39 %) were potential candidates for MitraClip(®) therapy, and 90 (44 %) died during the median follow-up time of 23 months.

CONCLUSION

A large fraction of patients with moderately severe or severe MR but not operated was detected. Medically treated patients had a bad prognosis and about 40 % of them were potential candidates for MitraClip(®) therapy.

Two-Year Outcomes of Surgical Treatment of Severe Ischemic Mitral Regurgitation

BACKGROUND

In a randomized trial comparing mitral-valve repair with mitral-valve replacement in patients with severe ischemic mitral regurgitation, we found no significant difference in the left ventricular end-systolic volume index (LVESVI), survival, or adverse events at 1 year after surgery. However, patients in the repair group had significantly more recurrences of moderate or severe mitral regurgitation. We now report the 2-year outcomes of this trial.

METHODS

We randomly assigned 251 patients to mitral-valve repair or replacement. Patients were followed for 2 years, and clinical and echocardiographic outcomes were assessed.

RESULTS

Among surviving patients, the mean (±SD) 2-year LVESVI was 52.6±27.7 ml per square meter of body-surface area with mitral-valve repair and 60.6±39.0 ml per square meter with mitral-valve replacement (mean changes from baseline, -9.0 ml per square meter and -6.5 ml per square meter, respectively). Two-year mortality was 19.0% in the repair group and 23.2% in the replacement group (hazard ratio in the repair group, 0.79; 95% confidence interval, 0.46 to 1.35; P=0.39). The rank-based assessment of LVESVI at 2 years (incorporating deaths) showed no significant between-group difference (z score=-1.32, P=0.19). The rate of recurrence of moderate or severe mitral regurgitation over 2 years was higher in the repair group than in the replacement group (58.8% vs. 3.8%, P<0.001). There were no significant between-group differences in rates of serious adverse events and overall readmissions, but patients in the repair group had more serious adverse events related to heart failure (P=0.05) and cardiovascular readmissions (P=0.01). On the Minnesota Living with Heart Failure questionnaire, there was a trend toward greater improvement in the replacement group (P=0.07).

CONCLUSIONS

In patients undergoing mitral-valve repair or replacement for severe ischemic mitral regurgitation, we observed no significant between-group difference in left ventricular reverse remodeling or survival at 2 years. Mitral regurgitation recurred more frequently in the repair group, resulting in more heart-failure-related adverse events and cardiovascular admissions. (Funded by the National Institutes of Health and Canadian Institutes of Health Research; ClinicalTrials.gov number, NCT00807040.).

Preoperative Three-Dimensional Valve Analysis Predicts Recurrent Ischemic Mitral Regurgitation After Mitral Annuloplasty

BACKGROUND

Valve repair for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings is characterized by high IMR recurrence rates. Patient-specific preoperative imaging-based risk stratification for recurrent IMR would optimize results. We sought to determine if prerepair three-dimensional (3D) echocardiography combined with a novel valve-modeling algorithm would be predictive of IMR recurrence 6 months after repair.

METHODS

Intraoperative transesophageal real-time 3D echocardiography was performed in 50 patients undergoing undersized ring annuloplasty for IMR and in 21 patients with normal mitral valves. A customized image analysis protocol was used to assess 3D annular geometry and regional leaflet tethering. IMR recurrence (≥ grade 2) was assessed with two-dimensional transthoracic echocardiography 6 months after repair.

RESULTS

Preoperative annular geometry was similar in all IMR patients, and preoperative leaflet tethering was significantly higher in patients with recurrent IMR (n=13) than in patients in whom IMR did not recur (n=37) (tethering index: 3.91 ± 1.01 vs 2.90 ± 1.17, p = 0.008; tethering angles of A3: 23.5° ± 8.9° vs 14.4° ± 11.4°, p = 0.012; P2: 44.4° ± 8.8° vs 28.2° ± 17.0°, p = 0.002; and P3: 35.2° ± 6.0° vs. 18.6° ± 12.7°, p < 0.001). Multivariate logistic regression analysis revealed the preoperative P3 tethering angle as an independent predictor of IMR recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84 to 1.00; p < 0.001).

CONCLUSIONS

3D echocardiography combined with valve modeling is predictive of recurrent IMR. Preoperative regional leaflet tethering of segment P3 is a strong independent predictor of IMR recurrence after undersized ring annuloplasty. In patients with a preoperative P3 tethering angle of 29.9° or larger, chordal-sparing valve replacement rather than valve repair should be strongly considered.

Surgical versus medical management of patients with acute ischemic mitral regurgitation: a systematic review

Aims

Acute ischemic mitral regurgitation (MR) is seen in patients with myocardial infarction and is associated with increased morbidity and mortality. The optimal treatment strategy of this condition however, is not well established. The aim of this manuscript is to conduct a systematic review of the medical literature to assess the relative benefits and harms of mitral valve surgery with medical therapy versus medical management alone for patients with acute ischemic MR of at least moderate severity.

Methods

We performed a literature search in MEDLINE, Embase.com, and Cochrane Central Register of Controlled Trials. We restricted the search to randomized clinical trials comparing surgical to medical management of acute ischemic MR. Exclusion criteria included non-randomized trials, trials enrolling patients with non-ischemic MR, and trials excluding acute ischemic MR. The primary outcomes were short-term and long term mortality. Two reviewers (WA, WA) screened titles and abstracts of identified citations independently and in duplicate using calibration exercises and standardized screening forms.

Results

The search strategy identified 887 citations (137 were duplicates and removed). Of the 750 titles, 709 were excluded (519 were non-relevant and 190 were review articles and case reports). Of the 41 remaining abstracts, 37 were retrospective cohorts and four excluded acute MR, leaving no eligible study for analysis. An ongoing study that is being conducted at Southern Illinois University entitled by “Medical Versus Surgical Management of Patients With Moderate Mitral Regurgitation Following Percutaneous Coronary Intervention for Myocardial Infarction: A Pilot Prospective Randomized Trial” was identified; however, it was just withdrawn after failing to enroll patients during 4 years.

Conclusion

This is an empty systematic review that identified no published randomized trials for the management of acute MR complicating acute MI. The only ongoing randomized study that was identified was just withdrawn after failing to enroll patients. There is an urgent need for conducing proper randomized trials in order to guide informed decision making in the treatment of acute ischemic MR.

PROSPERO registration number CRD42013005843

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1704-9) contains supplementary material, which is available to authorized users.

Predictive factors of long-term results following valve repair in ischemic mitral valve prolapse

BACKGROUND

In patients with ischemic mitral regurgitation, leaflet prolapse requires an accurate evaluation since surgical approach depends on valvular and subvalvular characteristics. This study aims to describe a cohort of patients over a long-term follow up, analyzing survival, reoperation and predictive factors of surgical outcomes.

METHODS AND RESULTS

From March 1994 to June 2011, 75 patients with ischemic mitral regurgitation and leaflet prolapse underwent surgical myocardial revascularization and mitral valve repair (90.7%) or replacement (9.3%). Our cohort was followed up until April 2015, with a mean follow up of 7 ± 3 years. Cardiac-related deaths occurred in 26 patients, with a mean survival of 114.2 months, including eight patients with in-hospital mortality. Reoperation was performed in 14 patients, due to valve repair failure. Twenty-six patients experienced moderate-to-severe mitral regurgitation. A preoperative LVEDD > 62 mm, LVESD > 52 mm, previous anteroseptal myocardial infarction, diffuse coronary artery disease, papillary anatomy type 1, partial rupture of the papillary muscle, A1-A2 scallop prolapse and postoperative mitral valve configuration (tenting area, tenting height, alfa-1 angle and alfa-2 angle) were identified as independent predictors of poor outcome. An index quantifying the stress on the annulus imparted by annuloplasty was elaborated and predicted endpoints.

CONCLUSION

Leaflet prolapse is an important entity in patients with ischemic mitral regurgitation, and its pathogenic mechanism mostly relies on papillary muscle lesion or elongation. Perioperative parameters describing geometric features of left ventricle, valvular and subvalvular components should be considered to provide a tailored approach for mitral valve repair, or to opt for immediate replacement in case of unfavorable geometry.

Repair or replace for severe ischemic mitral regurgitation: prospective randomized multicenter data

Ischemic mitral regurgitation (IMR) is a subset of functional mitral regurgitation (MR) that has the potential to impact an increasing number of patients in the future. This is in the context of a worldwide population, which continues to live longer with improved survival after myocardial infarction. Substantial data have accumulated over the past few decades demonstrating the negative effects of IMR. Further, significant research has been done to define the optimal surgical approach and several studies have compared mitral repair versus replacement for patients with severe mitral regurgitation (SMR). Studies supporting performance of mitral repair cite superior operative morbidity and mortality rates, while proponents of mitral replacement cite improved long-term durability and correction of MR. Lack of clinically robust Level I randomized controlled trial data have curtailed attempts to better define appropriate surgical treatment allocation over the past few decades. Recently, however, the Cardiothoracic Surgical Trials Network (CTSN) conducted the first randomized controlled trial, funded by the National Heart, Lung, and Blood Institute, the National Institute for Neurological Diseases and Stroke and the Canadian Institute for Health Research, to compare the performance of mitral repair versus replacement for SMR. Herein, the present review describes the design, results and implications of the CTSN SMR trial and its efforts to identify the most efficacious surgical approach to SMR. This review also describes CTSN investigation to predict the recurrence of MR after mitral repair.

Plenary presentations and public citations from The American Association for Thoracic Surgery

OBJECTIVE

We examined the impact of work presented in the plenary sessions at the meeting of The American Association for Thoracic Surgery (AATS), by determining how frequently the published papers corresponding to the session presentations during the past 20 years, were cited; those that were most cited were identified.

METHODS

We reviewed the AATS meeting programs from the 20-year period from 1994 to 2014 and identified the corresponding publications in the Journal of Thoracic and Cardiovascular Surgery (JTCVS) from all abstracts presented at the plenary sessions. Papers were categorized as cardiac, thoracic, or congenital. References were evaluated for subsequent citation in the Web of Science (WoS), and Google Scholar (GS). We determined both the median number of citations overall, and per year. For comparison, we evaluated numbers of citations in WoS from current JTCVS papers in issues containing the 3 most-cited plenary session papers.

RESULTS

Among 195 published plenary papers, the median number of citations in WoS and GS was 49 and 76, respectively. The median total number of citations in WoS was as follows: 51 for cardiac-category papers (n = 105); 61 for thoracic (n = 55), and 41 for congenital (n = 35). These values were higher than the median total number of citations for contemporary nonplenary JTCVS papers: cardiac (22, n = 55; P < .001); thoracic (31.5, n = 8; P = .183); and congenital (15.5, n = 24; P = .002) papers published in JTCVS. The median number of citations per year since publication for plenary publications was 5.9 (cardiac), 6 (thoracic), and 3.7 (congenital), respectively.

CONCLUSIONS

Publications corresponding to the plenary sessions of the AATS are highly cited and include some of the seminal studies in our field in the past 20 years.

Physiological Implications of Myocardial Scar Structure

Once myocardium dies during a heart attack, it is replaced by scar tissue over the course of several weeks. The size, location, composition, structure, and mechanical properties of the healing scar are all critical determinants of the fate of patients who survive the initial infarction. While the central importance of scar structure in determining pump function and remodeling has long been recognized, it has proven remarkably difficult to design therapies that improve heart function or limit remodeling by modifying scar structure. Many exciting new therapies are under development, but predicting their long-term effects requires a detailed understanding of how infarct scar forms, how its properties impact left ventricular function and remodeling, and how changes in scar structure and properties feed back to affect not only heart mechanics but also electrical conduction, reflex hemodynamic compensations, and the ongoing process of scar formation itself. In this article, we outline the scar formation process following a myocardial infarction, discuss interpretation of standard measures of heart function in the setting of a healing infarct, then present implications of infarct scar geometry and structure for both mechanical and electrical function of the heart and summarize experiences to date with therapeutic interventions that aim to modify scar geometry and structure. One important conclusion that emerges from the studies reviewed here is that computational modeling is an essential tool for integrating the wealth of information required to understand this complex system and predict the impact of novel therapies on scar healing, heart function, and remodeling following myocardial infarction.

Mitral valve repair versus replacement

Degenerative, ischemic, rheumatic and infectious (endocarditis) processes are responsible for mitral valve disease in adults. Mitral valve repair has been widely regarded as the optimal surgical procedure to treat mitral valve dysfunction of all etiologies. The supporting evidence for repair over replacement is strongest in degenerative mitral regurgitation. The aim of the present review is to summarize the data in each category of mitral insufficiency and to provide recommendations based upon this data.

Mitral valve repair over five decades

It has become evident that mitral valve (MV) repair is the preferable treatment for the majority of patients presenting with severe mitral regurgitation (MR). This success clearly testifies that the surgical procedure is accessible, reproducible and is carrying excellent long-lasting results. From the pre-extracorporeal circulation's era to the last percutaneous approaches, a large variety of techniques have been proposed to address the different features of MV diseases. This article aimed at reviewing chronologically the development of these dedicated techniques through their origins and the debates that they generated in the literature.

Saddle-Shaped Annuloplasty Improves Leaflet Coaptation in Repair for Ischemic Mitral Regurgitation

BACKGROUND

Current repair results for ischemic mitral regurgitation (IMR) with undersized annuloplasty rings are characterized by high IMR recurrence rates. Current annuloplasty rings treat annular dilatation, but they do little to improve (and may actually exacerbate) leaflet tethering. New saddle-shaped annuloplasty rings have been shown to maintain or restore a more physiologic annular and leaflet geometry and function. Using a porcine IMR model, we sought to demonstrate the influence of annuloplasty ring shape on leaflet coaptation.

METHODS

Eight weeks after posterolateral infarct, eight pigs with grade 2+ or higher IMR were randomized to undergo either a 28-mm flat ring annuloplasty (n = 4) or a 28-mm saddle-shaped ring annuloplasty (n = 4). Real-time three-dimensional echocardiography and a customized image analysis protocol allowed three-dimensional assessment of leaflet coaptation before and after annuloplasty.

RESULTS

Total leaflet coaptation area was significantly higher after saddle-shaped ring annuloplasty (109.6 ± 26.9 mm(2)) compared with flat ring annuloplasty (46.2 ± 7.7 mm(2), p <0.01). After annuloplasty, total coaptation area decreased by 87.5 mm(2) (or 65%) in the flat annuloplasty group (p = 0.01), whereas total coaptation area increased by 22.2 mm(2) (or 25%) in the saddle-shaped annuloplasty group (p = 0.28).

CONCLUSIONS

This study shows that the use of undersized saddle-shaped annuloplasty rings in mitral valve repair for IMR improves leaflet coaptation, whereas the use of undersized flat annuloplasty rings worsens leaflet coaptation. Because one of Carpentier's fundamental principles of mitral valve repair (durability) is to create a large surface of coaptation, saddle-shaped annuloplasty may increase repair durability.

Quantification and simulation of layer-specific mitral valve interstitial cells deformation under physiological loading

Within each of the four layers of mitral valve (MV) leaflet tissues there resides a heterogeneous population of interstitial cells that maintain the structural integrity of the MV tissue via protein biosynthesis and enzymatic degradation. There is increasing evidence that tissue stress-induced MV interstitial cell (MVIC) deformations can have deleterious effects on their biosynthetic states that are potentially related to the reduction of tissue-level maintenance and to subsequent organ-level failure. To better understand the interrelationships between tissue-level loading and cellular responses, we developed the following integrated experimental-computational approach. Since in vivo cellular deformations are not directly measurable, we quantified the in-situ layer-specific MVIC deformations for each of the four layers under a controlled biaxial tension loading device coupled to multi-photon microscopy. Next, we explored the interrelationship between the MVIC stiffness and deformation to layer-specific tissue mechanical and structural properties using a macro-micro finite element computational model. Experimental results indicated that the MVICs in the fibrosa and ventricularis layers deformed significantly more than those in the atrialis and spongiosa layers, reaching a nucleus aspect ratio of 3.3 under an estimated maximum physiological tension of 150N/m. The simulated MVIC moduli for the four layers were found to be all within a narrow range of 4.71-5.35kPa, suggesting that MVIC deformation is primarily controlled by each tissue layer's respective structure and mechanical behavior rather than the intrinsic MVIC stiffness. This novel result further suggests that while the MVICs may be phenotypically and biomechanically similar throughout the leaflet, they experience layer-specific mechanical stimulatory inputs due to distinct extracellular matrix architecture and mechanical behaviors of the four MV leaflet tissue layers. This also suggests that MVICs may behave in a layer-specific manner in response to mechanical stimuli in both normal and surgically modified MVs.

The future of transcatheter mitral valve interventions: competitive or complementary role of repair vs. replacement?

Transcatheter mitral interventions has been developed to address an unmet clinical need and may be an alternative therapeutic option to surgery with the intent to provide symptomatic and prognostic benefit. Beyond MitraClip therapy, alternative repair technologies are being developed to expand the transcatheter intervention armamentarium. Recently, the feasibility of transcatheter mitral valve implantation in native non-calcified valves has been reported in very high-risk patients. Acknowledging the lack of scientific evidence to date, it is difficult to predict what the ultimate future role of transcatheter mitral valve interventions will be. The purpose of the present report is to review the current state-of-the-art of mitral valve intervention, and to identify the potential future scenarios, which might benefit most from the transcatheter repair and replacement devices under development.

Determinants of functional capacity after mitral valve annuloplasty or replacement for ischemic mitral regurgitation

OBJECTIVE

To identify the exercise echocardiographic determinants of long-term functional capacity, in patients with chronic ischemic mitral regurgitation, after restrictive mitral valve annuloplasty (RMA) or mitral valve replacement (MVR).

METHODS

We retrospectively analyzed 121 patients with significant chronic ischemic mitral regurgitation, who underwent RMA (n = 62) or MVR (n = 59), between 2005 and 2011. Preoperatively, all patients underwent a resting echocardiographic examination, and a 6-minute walking test (6-MWT) to measure distance. Resting and exercise stress echocardiography, and the 6-MWT were repeated at 41 ± 16.5 months.

RESULTS

After surgery, the 6-MWT distance significantly improved in the MVR group, and decreased in the RMA group (+37 ± 39 m vs -24 ± 49 m, respectively; P < .0001). Exercise indexed effective orifice area was significantly higher in the MVR, versus the RMA, group (MVR: change from 1.3 ± 0.2 cm(2)/m(2) to 1.5 ± 0.3 cm(2)/m(2); RMA: change from 1.1 ± 0.3 cm(2)/m(2) to 1.2 ± 0.3 cm(2)/m(2); P = .001). The mean mitral gradients significantly increased from rest to exercise, in both groups, but to a greater extent in the RMA group (change from 4.4 ± 1.4 to 11 ± 3.6 mm Hg; MVR: change from 4.3 ± 1.8 to 9 ± 3.5 mm Hg; P = .006). On multivariate analysis, MVR and exercise indexed effective orifice area were the main independent determinants of postoperative 6-MWT. In the RMA group, 25 patients experienced late mitral regurgitation recurrence, severe in 9 (14%) of them. The rate of postoperative cardiovascular events was significantly higher in the RMA group (21% vs MVR: 8%; P = .03). Follow-up survival was 83% in the RMA group and 88% in the MVR group (P = .54).

CONCLUSIONS

For chronic ischemic mitral regurgitation, MVR versus RMA was associated with better postoperative exercise hemodynamic performance and long-term functional capacity.

Safety and feasibility of a novel adjustable mitral annuloplasty ring: a multicentre European experience

OBJECTIVES

Recurrent mitral regurgitation is a significant problem after mitral valve repair in patients with functional valve disease. We report the safety and feasibility of a novel adjustable mitral annuloplasty device that permits downsizing of the anterior–posterior diameter late after initial surgery.

METHODS

In this multicentre, non-randomized, observational register, patients with moderate or severe mitral regurgitation undergoing surgical mitral valve repair with the MiCardia EnCor_SQ™ Mitral Valve Repair system were evaluated. Patient characteristics, operative specifications and results as well as postoperative follow-up were collected for all five centres.

RESULTS

Ninety-four patients with a median age of 71 (64–75) years (EuroSCORE II 6.7 ± 6.3; 66% male, 48% ischaemic MR, 37% dilated cardiomyopathy and 15% degenerative disease) were included. Operative mortality was 1% and the 1-year survival was 93%. Ring adjustment was attempted in 12 patients at a mean interval of 9 ± 6 months after surgery. In three of these attempts, a technical failure occurred. In 1 patient, mitral regurgitation was reduced two grades, in 2 patients mitral regurgitation was reduced one grade and in 6 patients, mitral regurgitation did not change significantly. The mean grade of mitral regurgitation changed from 2.9 ± 0.9 to 2.1 ± 0.7 (P = 0.02). Five patients were reoperated after 11 ± 9 months (Ring dehiscence: 2; failed adjustment: 3).

CONCLUSION

We conclude that this device may provide an additional treatment option in patients with functional mitral regurgitation, who are at risk for reoperation due to recurrent mitral regurgitation. Clinical results in this complex disease were ambiguous and patient selection seems to be a crucial step for this device. Further trials are required to estimate the clinical value of this therapeutic concept.

Novel Echocardiographic Indices as Predictors of Immediate Recurrence after Undersized Ring Annuloplasty for Ischemic Mitral Regurgitation

BACKGROUND AND AIM

Ischemic mitral regurgitation (IMR) is among the most serious complications of myocardial infarction which doubles the late mortality; mainly treated by undersizing ring annuloplasty. To find some preoperative echocardiographic indices that predict immediate failure of mitral valve annuloplasty (MVA), we designed the present study with more focusing on some novel parameters.

METHOD

Transthoracic echocardiography (TTE) indices of consecutive patients referred with 3+ or 4+ IMR were registered 24 hours before surgery. Thirty days later, a second TTE was performed. According to the results, the patients were categorized as the "successful" group (with 1+ or less mitral regurgitation) and the "unsuccessful" group (with 2+ or higher MR). Preoperative TTE indices were compared among the two groups using suitable statistical tests.

RESULTS

Of the total of 126 cases, 68 had successful and 58 had unsuccessful MVA. Statistically significant differences were found between the two groups for left ventricular ejection fraction (LVEF) (P = 0.007), left ventricular end systolic volume (LVESV) (P = 0.044), and basal-interpapillary muscle distance (IPMD) diastolic-to-systolic ratio (DSR) (P = 0.008). Receiver Operating Characteristic analysis demonstrated 37.5%, 3.85 cm(3) , and 1.25, as the best cutoff points for LVEF (P = 0.03, sensitivity: 81%, specificity: 69%), LVESV (P = 0.023, sensitivity: 83%, specificity: 57%), and basal-IPMD DSR (P = 0.001, sensitivity: 100%, specificity: 95%), respectively.

CONCLUSION

Among all TTE indices, LVEF, LVESV, and basal-IPMD DSR were helpful to differentiate between the successful and unsuccessful MVA results. We believe the basal-IPMD DSR as a novel index could be targeted in the future studies.

Predicting recurrent mitral regurgitation after mitral valve repair for severe ischemic mitral regurgitation

OBJECTIVES

The Cardiothoracic Surgical Trials Network recently reported no difference in the primary end point of left ventricular end-systolic volume index at 1 year postsurgery in patients randomized to repair (n = 126) or replacement (n = 125) for severe ischemic mitral regurgitation. However, patients undergoing repair experienced significantly more recurrent mitral regurgitation than patients undergoing replacement (32.6% vs 2.3%). We examined whether baseline echocardiographic and clinical characteristics could identify those who will develop moderate/severe recurrent mitral regurgitation or die.

METHODS

Our analysis includes 116 patients who were randomized to and received mitral valve repair. Logistic regression was used to estimate a model-based probability of recurrence or death from baseline factors. Receiver operating characteristic curves were constructed from these estimated probabilities to determine classification cut-points maximizing accuracy of prediction based on sensitivity and specificity.

RESULTS

Of the 116 patients, 6 received a replacement before leaving the operating room; all other patients had mild or less mitral regurgitation on intraoperative echocardiogram after repair. During the 2-year follow-up period, 76 patients developed moderate/severe mitral regurgitation or died (53 mitral regurgitation recurrences, 13 mitral regurgitation recurrences and death, and 10 deaths). The mechanism for recurrent mitral regurgitation was largely mitral valve leaflet tethering. Our model (including age, body mass index, sex, race, effective regurgitant orifice area, basal aneurysm/dyskinesis, New York Heart Association class, history of coronary artery bypass grafting, percutaneous coronary intervention, or ventricular arrhythmias) yielded an area under the receiver operating characteristic curve of 0.82.

CONCLUSIONS

The model demonstrated good discrimination in identifying patients who will survive 2 years without recurrent mitral regurgitation after mitral valve repair. Although our results require validation, they offer a clinically relevant risk score for selection of surgical candidates for this procedure.

Percutaneous mitral valve repair for mitral regurgitation in high-risk patients: results of the EVEREST II study

BACKGROUND

The EVEREST II (Endovascular Valve Edge-to-Edge REpair STudy) High-Risk registry and REALISM Continued Access Study High-Risk Arm are prospective registries of patients who received the MitraClip device (Abbott Vascular, Santa Clara, California) for mitral regurgitation (MR) in the United States.

OBJECTIVES

The purpose of this study was to report 12-month outcomes in high-risk patients treated with the percutaneous mitral valve edge-to-edge repair.

METHODS

Patients with grades 3 to 4+ MR and a surgical mortality risk of ≥12%, based on the Society of Thoracic Surgeons risk calculator or the estimate of a surgeon coinvestigator following pre-specified protocol criteria, were enrolled.

RESULTS

In the studies, 327 of 351 patients completed 12 months of follow-up. Patients were elderly (76 ± 11 years of age), with 70% having functional MR and 60% having prior cardiac surgery. The mitral valve device reduced MR to ≤2+ in 86% of patients at discharge (n = 325; p < 0.0001). Major adverse events at 30 days included death in 4.8%, myocardial infarction in 1.1%, and stroke in 2.6%. At 12 months, MR was ≤2+ in 84% of patients (n = 225; p < 0.0001). From baseline to 12 months, left ventricular (LV) end-diastolic volume improved from 161 ± 56 ml to 143 ± 53 ml (n = 203; p < 0.0001) and LV end-systolic volume improved from 87 ± 47 ml to 79 ± 44 ml (n = 202; p < 0.0001). New York Heart Association functional class improved from 82% in class III/IV at baseline to 83% in class I/II at 12 months (n = 234; p < 0.0001). The 36-item Short Form Health Survey physical and mental quality-of-life scores improved from baseline to 12 months (n = 191; p < 0.0001). Annual hospitalization rate for heart failure fell from 0.79% pre-procedure to 0.41% post-procedure (n = 338; p < 0.0001). Kaplan-Meier survival estimate at 12 months was 77.2%.

CONCLUSIONS

The percutaneous mitral valve device significantly reduced MR, improved clinical symptoms, and decreased LV dimensions at 12 months in this high-surgical-risk cohort. (Endovascular Valve Edge-to-Edge REpair STudy [EVERESTIIRCT]; NCT00209274).

Surgical Strategy for Moderate Ischemic Mitral Valve Regurgitation: Repair or Ignore?

<p><strong>Background:</strong> Ischemic heart disease is a significant complication of atherosclerosis. Myocardial infarction after the development of coronary artery disease can lead to a number of serious complications, including ischemic mitral regurgitation (IMR). Currently there is no consensus regarding the preferred therapeutic modality for moderately severe IMR. In this study, the postoperative outcome of concomitant coronary artery bypass (CABG) and mitral valve repair was compared with that of CABG alone in two groups of patients with moderately severe IMR.</p><p><strong>Methods:</strong> A total of 84 patients who underwent operations for coronary artery disease and moderately severe IMR were included in the study. Preoperative demographic and clinical characteristics were recorded at the time of admission. The severity of mitral regurgitation was graded using transthoracic echocardiography and left ventriculography.</p><p><strong>Results:</strong> Significant postoperative improvements were observed in ejection fraction and systolic diameter compared to preoperative values (<em>P</em> = .006 and <em>P</em> = .020 respectively, in the intervention group, <em>P</em> = .001 and <em>P</em> = .001 respectively, in the control group). The decrease in pulmonary artery pressure (PAP) was significant only in the intervention group (<em>P</em> = .001). There was a significantly marked reduction in the severity of IMR in the intervention group compared to control.</p><p><strong>Conclusion:</strong> Surgical repair of the mitral valve in conjunction with CABG for moderately severe IMR appears to be more effective than isolated CABG for certain outcome parameters, including decreased severity of mitral regurgitation and decreased pulmonary artery pressure.</p>

MitraClip for severe symptomatic mitral regurgitation in patients at high surgical risk: a comprehensive systematic review

BACKGROUND

The optimal treatment of patients with severe mitral regurgitation (MR) at high surgical risk (HSR) is unknown. Recently, the EVEREST II (Endovascular Valve Edge-to-Edge Repair) High Risk Study suggested MitraClip (MC) was a safe and effective treatment option.

METHODS

We performed a search strategy for MC or mitral valve surgery (MVS) in patients at HSR for surgical mortality (logistic EuroSCORE >18 or STS score > 10) using Medline databases, proceedings of international meetings, and the STS database. We identified 21 studies utilizing MC (n = 3,198) and MVS (n = 3,265, >90% from the STS database) from 2003 to 2013. Information about patient characteristics, surgical risk, and 30-day and 1-year outcomes were extracted.

RESULTS

Patients who underwent MC or MVS had a mean age of 74 ± 10 years with no differences in surgical risk, NYHA class, or MR grade (P = 0.46). Technical success was achieved in 96% of patients undergoing MC versus 98% in the MVS group (P = 0.45). Patients undergoing MC were treated with one or two MC in 90% (n = 2,878) with only a few requiring repeat MC (0.4%, n = 13) or mitral surgery (0.3%, n = 52) at 30 days. The pooled event rates for mortality was 3.2% (95% CI [2.5-4.2]), stroke was 1.1% (95% CI [0.7-0.2]) at 30 days. At 31 days to 1 year, the pooled event rate for mortality was 13.0% [95% CI (9-18.3)], stroke was 1.6% [95% CI (0.8-3.2)], and repeat MVS was 1.3% [95% CI (0.7-2.6)] with the majority of patients in the mild/moderate MR grade and NYHA class after MC. The 30-day event rates for mortality and stroke were 16.8% (95% CI [14-19]) and 4.5% (95% CI [3.9-5.3]) after MVS, respectively.

CONCLUSION

Based on high risk MC studies and high risk MVS data predominantly from STS database, patients with severe MR who are at HSR can be effectively treated with MC or MVS. MC can be safely implanted in high risk patients with relatively low mortality and stroke risk.

Mitral valve repair versus replacement in patients with ischaemic mitral regurgitation and depressed ejection fraction: risk factors for early and mid-term mortality†

OBJECTIVES

Mitral valve (MV) surgery for ischaemic mitral regurgitation (IMR) in patients with depressed left ventricular ejection fraction (LVEF) is associated with poor outcomes. The optimal surgical strategy for IMR in these patients remains controversial. The objective of this study was to compare the early mortality and mid-term survival of MV repair versus MV replacement in patients with IMR and depressed LVEF undergoing coronary artery bypass grafting (CABG).

METHODS

A retrospective, observational, cohort study was undertaken of prospectively collected data on 126 consecutive CABG patients with IMR and LVEF <40% undergoing either MV repair (n = 98, 78%) or MV replacement (n = 28, 22%) between July 2002 and February 2011.

RESULTS

The overall mortality rate was 7.9% (n = 10). MV replacement was associated with a 4-fold increase in the risk of death compared with MV repair [17.9%, n = 5 vs 5.1%, n = 5; odds ratio (OR) 4.04, 95% confidence interval (CI) 1.08-15.1, P = 0.04]. However, after adjusting for preoperative risk factors, the type of surgical procedure was not an independent risk factor for early mortality (OR 0.1, 95% CI 0.01-31, P = 0.7). Multivariable analysis showed that preoperative LVEF (OR 0.8, 95% CI 0.6-0.9, P = 0.018), preoperative B-type natriuretic peptide (BNP) levels (OR 1.01, 95% CI 1-1.02, P = 0.025), preoperative left ventricle end-systolic diameter (OR 0.8, 95% CI 0.7-1.0, P = 0.05) and preoperative left atrial diameter (OR 1.3, 95% CI 1.0-1.6, P = 0.015) were independent risk factors of early mortality. At the median follow-up of 45 months (interquartile range 20-68 months), the mid-term survival rate was 74% in the MV repair group and 70% in the MV replacement group (P = 0.08). At follow-up, predictors of worse survival were BNP levels [hazard ratio (HR) 1.0, 95% CI 1.0-1.01, P = 0.047], preoperative renal failure (HR 4.6, 95% CI 1.1-20.3, P = 0.039) and preoperative atrial fibrillation (HR 3.3, 95% CI 1.1-10, P = 0.032).

CONCLUSIONS

MV repair in CABG patients with IMR and depressed LVEF is not superior to MV replacement with regard to operative early mortality and mid-term survival.

Repair or prosthesis insertion in ischemic mitral regurgitation: Two faces of the same medal

Objective

The proper treatment of chronic ischemic mitral regurgitation (CIMR) is still under evaluation. The different role of mitral valve repair (MVr) or mitral valve prosthesis insertion (MVPI) is still not defined.

Methods

From May 2009 to December 2011 167 patients with ejection fraction (EF) ≤ 40% had MV surgery for CIMR, MVr in 135 (80.8%) and MVPI in 32 (19.2%). Indication to MVPI was a MV coaptation depth > 10 mm. EF was lower (26 ± 7 vs 32 ± 6, p = 0.0000) in MVPI, whereas MR grade (3.6 ± 0.8 vs 2.7 ± 0.9, p = 0.0000), left ventricle dimensions (end diastolic, LVEDD, 62 ± 7 vs 57 ± 6 mm, p = 0.0001; end systolic, LVESD, 49 ± 8 vs 44 ± 8 mm, p = 0.0018), systolic pulmonary artery pressure (51 ± 22 vs 41 ± 16 mm Hg, p = 0.0037) and NYHA Class (3.6 ± 0.5 vs 2.8 ± 0.6, p = 0.0000) were higher.

Results

In-hospital mortality was similar (3.1 vs 3.7%) as well as 3-year survival (86 ± 6 vs 88 ± 4) and survival in NYHA Class I/II (80 ± 5 vs 83 ± 4). One hundred thirty nine patients had an echocardiographic evaluation after a minimum of 4 months (13 ± 8). EF rose significantly in both groups (from 26 ± 7% to 30 ± 4%, p = 0.0122, and from 32 ± 6% to 35 ± 8%, p = 0.0018). LVESD reduced significantly in both groups (from 49 ± 8 to 43 ± 9 mm, p = 0.0109, and from 44 ± 8 to 41 ± 7 mm, p = 0.0033). MR grade was significantly lower in patients who had MVPI (0.1 ± 0.2 vs 0.3 ± 0.3, p = 0.0011).

Conclusions

With appropriate indications, MVPI is a safe procedure which provides similar results to MVr with lower MR return, even if addressed to patients with worse preoperative parameters.

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Papillary muscle relocation and mitral annuloplasty in ischemic mitral valve regurgitation: midterm results

OBJECTIVES

The surgical approach for ischemic mitral regurgitation remains unclear. Many studies are in favor of adding the subvalvular procedure to mitral annuloplasty to reduce recurrent mitral regurgitation. This study reports the clinical and echocardiographic outcomes of papillary muscle relocation combined with mitral annuloplasty.

METHODS

From 2003, 115 patients with severe ischemic mitral regurgitation who underwent papillary muscle relocation plus nonrestrictive mitral annuloplasty and coronary artery bypass grafting were retrospective analyzed. Patients' mean age was 52±12.8 years, New York Heart Association class III or IV was 71%, and preoperative left ventricular ejection fraction was 43%±6%. The study end points were New York Heart Association functional class, reversal in left ventricle remodeling, reduction of mean tenting area and mean coaptation depth, freedom from cardiac-related deaths and events, and freedom from recurrent mitral regurgitation. Follow-up data were obtained in all patients and were 100% complete. Mean follow-up was 45±6 months.

RESULTS

Five-year freedom from cardiac-related death and events was 91.3%±1.6% and 84%±2.2%, respectively. Recurrent mitral regurgitation more than moderate occurred in 3 patients (2.7%). Reversal in left ventricular remodeling, measured by a change in the end-diastolic and systolic diameter, was observed in our patients (P<.05). The postoperative mean tenting area and mean coaptation depth were 1.1±0.2 cm2 and 0.5±0.2 cm, respectively; 95% of the patients were in New York Heart Association functional class I and II.

CONCLUSIONS

In patients with ischemic mitral regurgitation, papillary muscle relocation plus nonrestrictive mitral annuloplasty promotes a significant reversal in left ventricular remodeling, with a considerable decrease in tenting area and coaptation depth. Our approach is a durable method to reduce the recurrence of mitral insufficiency.

Asymmetric versus symmetric tethering patterns in ischemic mitral regurgitation: geometric differences from three-dimensional transesophageal echocardiography

BACKGROUND

Ischemic mitral regurgitation (IMR) results from mitral leaflet tethering from left ventricular remodeling. Heterogeneity in local or global left ventricular remodeling can result in differential tethering patterns and affect mitral valve function and the degree of mitral regurgitation. The aims of this study were to compare mitral valve geometry in asymmetric and symmetric tethering patterns using three-dimensional transesophageal echocardiography and to examine the impact of tethering pattern on IMR severity.

METHODS

Sixty-two patients with moderate or greater IMR underwent three-dimensional transesophageal echocardiography for the assessment of mitral valve geometry. Symmetric and asymmetric tethering patterns were determined by mitral regurgitation jet direction and coaptation of the mitral leaflets. The ratio of posterior to anterior leaflet tethering angle was a measure of tethering pattern (the higher the ratio, the more asymmetric the pattern). Overall tethering degree was assessed by tenting volume (TV).

RESULTS

Compared with the symmetric group, the asymmetric group had less annular dilatation, greater annular heights (10.3 ± 1.9 vs 8.5 ± 1.9 mm, P < .01), greater ratios of posterior to anterior leaflet tethering angle (3.19 ± 0.88 vs 1.95 ± 0.46, P < .01), and smaller TVs with more posterior displacement of the coaptation line. Vena contracta normalized to TV was greater in the asymmetric group (0.38 ± 0.24 vs 0.19 ± 0.13 cm/mL, P < .01). Multivariate analysis showed that both ratio of posterior to anterior leaflet tethering angle (β = 0.46, P < .001) and TV (β = 0.41, P = .001) were predictors of IMR severity.

CONCLUSIONS

Differences in mitral valve geometry are observed between asymmetric and symmetric tethering patterns in IMR. IMR degree is affected by both the pattern of tethering and the total degree of tethering. For the same degree of tethering, an asymmetric pattern is associated with increased MR severity. The pattern of mitral leaflet tethering may be considered in therapeutic decision making.

Midterm outcomes of chordal cutting in combination with downsized ring annuloplasty for ischemic mitral regurgitation

PURPOSE

We describe midterm outcomes after division of secondary chords (chordal cutting) combined with downsized ring annuloplasty for ischemic mitral regurgitation (IMR).

METHODS

We compared the clinical outcomes in patients who underwent chordal cutting with downsized ring annuloplasty (CC-group, n = 15) and those who underwent conventional ring annuloplasty only (Conventional-group, n = 35) for IMR. Follow-up was complete in all patients. The median follow-up time was 4.1 years.

RESULTS

Thirty-day mortality was 0% in CC-group and 20% in Conventional-group. The overall survival rate at 5-year was 80.8% ± 12.6% in CC-group and 61.7% ± 8.4% in Conventional-group (Log-rank, p = 0.145). The freedom rate from valve-related events at 5 year was 84.6% ± 10.0% in CC-group and 65.3% ± 10.1% in Conventional-group (Log-rank, p = 0.213). Recurrence of severe mitral regurgitation was revealed in 3 patients of CC-group. Preoperative tenting height was the significant predictor of mitral regurgitation recurrence. In CC-group, the mean left ventricular ejection fraction was 38.0% ± 14.0%, which was similar to the preoperative value of 40.0% ± 13.2% (p = 0.349).

CONCLUSIONS

Chordal cutting with downsized ring annuloplasty for IMR is a simple method and provides satisfactory early outcomes. However, it carries with high recurrence of MR especially for patients with high tenting height.

Ischemic (functional) mitral regurgitation

Mitral regurgitation (MR) is a frequent complication of myocardial infarction and coronary artery disease that is associated with adverse prognosis. The main mechanism of ischemic MR relates to distortion of the spatial relationships between the mitral valve and papillary muscles secondary to ventricular remodeling. The evidence that treatment of ischemic MR improves long-term survival still remains unclear, and further studies are needed to determine whether correcting ischemic MR will improve survival and/or symptoms.

Quantitative Evaluation of Annuloplasty on Mitral Valve Chordae Tendineae Forces to Supplement Surgical Planning Model Development

PURPOSE

Computational models of the heart's mitral valve (MV) exhibit potential for preoperative surgical planning in ischemic mitral regurgitation (IMR). However challenges exist in defining boundary conditions to accurately model the function and response of the chordae tendineae to both IMR and surgical annuloplasty repair. Towards this goal, a ground-truth data set was generated by quantifying the isolated effects of IMR and mitral annuloplasty on leaflet coaptation, regurgitation, and tethering forces of the anterior strut and posterior intermediary chordae tendineae.

METHODS

MVs were excised from ovine hearts (N=15) and mounted in a pulsatile heart simulator which has been demonstrated to mimic the systolic MV geometry and coaptation of healthy and chronic IMR sheep. Strut and intermediary chordae from both MV leaflets (N=4) were instrumented with force transducers. Tested conditions included a healthy control, IMR, oversized annuloplasty, true-sized annuloplasty, and undersized mitral annuloplasty. A2-P2 leaflet coaptation length, regurgitation, and chordal tethering were quantified and statistically compared across experimental conditions.

RESULTS

IMR was successfully simulated with significant increases in MR, tethering forces for each of the chordae, and decrease in leaflet coaptation (p<.05). Compared to the IMR condition, increasing levels of downsized annuloplasty significantly reduced regurgitation, increased coaptation, reduced posteromedial papillary muscle strut chordal forces, and reduced intermediary chordal forces from the anterolateral papillary muscle (p<.05).

CONCLUSIONS

These results provide for the first time a novel comprehensive data set for refining the ability of computational MV models to simulate IMR and varying sizes of complete rigid ring annuloplasty.