Mechanistic Insights into Ischemic Mitral Regurgitation: Echocardiographic and Surgical Implications

Mitral Valve Segmentation and Tracking from Transthoracic Echocardiography Using Deep Learning

OBJECTIVE

Valvular heart diseases (VHDs) pose a significant public health burden, and deciding the best treatment strategy necessitates accurate assessment of heart valve function. Transthoracic echocardiography (TTE) is the key modality to evaluate VHDs, but the lack of standardized quantitative measurements leads to subjective and time-consuming assessments. We aimed to use deep learning to automate the extraction of mitral valve (MV) leaflets and annular hinge points from echocardiograms of the MV, improving standardization and reducing workload in quantitative assessment of MV disease.

METHODS

We annotated the MV leaflets and annulus points in 2931 images from 127 patients. We propose an approach for segmenting the annotated features using Attention UNet with deep supervision and weight scheduling of the attention coefficients to enforce saliency surrounding the MV. The derived segmentation masks were used to extract quantitative biomarkers for specific MV leaflet scallops throughout the heart cycle.

RESULTS

Evaluation performance was summarized using a Dice score of 0.63 ± 0.14, annulus error of 3.64 ± 2.53 and leaflet angle error of 8.7 ± 8.3°. Leveraging Attention UNet with deep supervision robustness of clinically relevant metrics was improved compared with UNet, reducing standard deviations by 2.7° (angle error) and 0.73 mm (annulus error). We correctly identified cases of MV prolapse, cases of stenosis and healthy references from a clinical material using the derived biomarkers.

CONCLUSION

Robust deep learning segmentation and tracking of MV morphology and motion is possible by leveraging attention gates and deep supervision, and holds promise for enhancing VHD diagnosis and treatment monitoring.

Prevalence, mechanisms, and prognostic impact of dynamic mitral regurgitation assessed by isometric handgrip exercise

AIMS

The extent of mitral regurgitation (MR) may vary depending on the haemodynamic situation; thus, exercise testing plays an important role in assessing the haemodynamic relevance of MR. We aim to assess prevalence, mechanisms, and prognostic impact of exercise-induced changes in MR in patients with degenerative MR (DegMR) and functional MR (FMR).

METHODS AND RESULTS

We enrolled 367 patients with at least mild MR who underwent standardized echocardiography at rest and during handgrip exercise. Handgrip exercise led to an increase in MR by one grade or more in 19% of DegMR and 28% of FMR patients. In FMR, patients with exercise-induced increases in MR, handgrip exercise led to a reduction in left ventricular stroke volume index, being maintained in DegMR patients. Exercise-induced changes in systolic pulmonary artery pressure were linked to changes in effective regurgitant orifice area (DegMR: r = 0.456; P < 0.001; FMR: r = 0.326; P < 0.001). Thus, 26% of patients with DegMR and FMR developed pulmonary hypertension during exercise. In both cohorts, a significant proportion of patients with non-severe MR at rest and exercise-induced severe MR underwent mitral valve surgery/intervention during follow-up. In FMR patients (but not in DegMR patients), early mitral valve surgery/intervention was independently associated with lower event rates during follow-up [0.177 (0.027-0.643); P = 0.025].

CONCLUSIONS

Handgrip exercise echocardiography provides important information regarding the dynamic nature of MR, exercise-induced changes in left ventricular function, and pulmonary circulation with subsequent consequences for further therapeutic decision making. Thus, it should be considered as a diagnostic tool in symptomatic patients with non-severe MR at rest.

A geometry-based finite element tool for evaluating mitral valve biomechanics

Mitral valve function depends on its complex geometry and tissue health, with alterations in shape and tissue response affecting the long-term restorarion of function. Previous computational frameworks for biomechanical assessment are mostly based on patient-specific geometries; however, these are not flexible enough to yield a variety of models and assess mitral closure for individually tuned morphological parameters or material property representations. This study details the finite element approach implemented in our previously developed toolbox to assess mitral valve biomechanics and showcases its flexibility through the generation and biomechanical evaluation of different models. A healthy valve geometry was generated and its computational predictions for biomechanics validated against data in the literature. Moreover, two mitral valve models including geometric alterations associated with disease were generated and analysed. The healthy mitral valve model yielded biomechanical predictions in terms of valve closure dynamics, leaflet stresses and papillary muscle and chordae forces comparable to previous computational and experimental studies. Mitral valve function was compromised in geometries representing disease, expressed by the presence of regurgitating areas, elevated stress on the leaflets and unbalanced subvalvular apparatus forces. This showcases the flexibility of the toolbox concerning the generation of a range of mitral valve models with varying geometric definitions and material properties and the evaluation of their biomechanics.

Concomitant Mitral Valve Surgery Versus No Intervention in Patients with Moderate Ischemic Mitral Regurgitation Undergoing Coronary Artery Bypass Grafting: A Propensity Score Analysis

Objectives

Ischemic mitral valve regurgitation (IMR) in patients undergoing coronary artery bypass grafting (CABG) is associated with worse long-term outcomes. This study aimed to assess the impact of mitral valve repair with CABG in patients with moderate IMR.

Materials

This observational study enrolled 3,215 consecutive patients from the Juntendo CABG registry with moderate IMR and multivessel coronary artery disease who underwent CABG between 2002 and 2017.

Methods

The CABG alone and CABG with mitral valve surgery (MVs) groups were compared. The propensity score was calculated for each patient. Long-term all-cause death, cardiac death, and major adverse cardiac and cerebrovascular events (MACCEs) were compared.

Results

Our database had 101 patients who underwent CABG with moderate IMR. Propensity score matching selected 40 pairs for final analysis. MVs was associated with increased risks of postoperative atrial fibrillation, blood transfusion, and longer hospitalization. Long-term outcomes, including all-cause mortality, cardiac mortality, and the incidence of MACCEs were similar.

Conclusion

Surgical treatment of moderate IMR combined with CABG was related to increased risk of several non-fatal short-term complications when compared to CABG alone, with similar long-term outcomes. Further studies are needed to determine the effects of MVs in patients with moderate IMR and severe coronary artery disease.

Pathophysiology, Echocardiographic Diagnosis, and Treatment of Atrial Functional Mitral Regurgitation: JACC State-of-the-Art Review

The conventional view holds that functional mitral regurgitation (MR) is caused by restriction of leaflet motion resulting from displacement of the papillary muscle-bearing segments of the left ventricle. In the past decade, evidence has accrued suggesting functional MR can also be caused by left atrial enlargement. This underrecognized cause of secondary MR-atrial functional MR (AF-MR)-is mechanistically linked to annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering. AF-MR has been described in patients with atrial fibrillation and heart failure with preserved ejection fraction. Preliminary data suggest rhythm control may decrease MR severity in patients with atrial fibrillation. Additionally, several studies have reported reductions in MR and symptomatic improvement with restrictive annuloplasty and transcatheter edge-to-edge repair. This review discusses the pathophysiology, echocardiographic diagnosis, and treatment of AF-MR. AF-tricuspid regurgitation is also discussed.

Percutaneous Edge-to-Edge Mitral Valve Repair for Functional Mitral Regurgitation

The presence and severity of functional mitral regurgitation (FMR) is associated with worse outcomes in patients with heart failure and reduced ejection fraction. Prior to the availability of percutaneous mitral valve repair, management for FMR has been limited to medical therapy, cardiac resynchronization therapy for a specific subset of patients and surgery which has yet to demonstrate mortality benefits. Transcatheter edge-to-edge repair (TEER) of the mitral valve has emerged in the past decade as an invaluable member of the armamentarium against FMR with the 2 landmark randomized controlled trials providing deep insights on patient selection. In addition, TEER has spurred the rapid advancement in our understanding of FMR. This article seeks to provide an overview as well as our current understanding on the role of TEER in FMR.

Variable definitions and treatment approaches for atrial functional mitral regurgitation: A scoping review of the literature

OBJECTIVES

Atrial functional mitral regurgitation (AFMR) is a subtype of functional mitral regurgitation due to longstanding atrial fibrillation (AF) or heart failure with preserved ejection fraction. The variation in AFMR' definition and the common mode of treatment described in the literature remain unknown.

METHODS

We performed a scoping review of studies that surgically treated AFMR to characterize the existing variability in the definition of AFMR, the type of operations performed for AFMR valvulopathy, and the treatment for the chronic AF. We searched Medline, EMBASE, Cochrane Library, Scopus, and Web of Science since their inceptions for studies of patients affected by AFMR and surgically treated for their valvulopathy.

RESULTS

Twelve studies (n = 494 patients) met eligibility criteria. All studies excluded patients with signs of left ventricular (LV) dysfunction, but the way additional parameters were used to define AFMR at a more granular level varied across studies: nine studies (75%) used the presence of AF to define their AFMR cohorts, with five (41.2%) requiring a history of AF of >1 year; additionally, the threshold values for the LV ejection fraction differed (45%-55%). Isolated mitral annuloplasty was performed in 96.2% of patients. Broad variability was detected in the proportion of patients undergoing the Cox-Maze procedure (range, 17.8%-79.5%), pulmonary vein isolation (0.0%-66.7%), and left atrial appendage ligation (0.0%-100.0%).

CONCLUSIONS

AFMR remains variably defined in surgical studies, making comparisons across studies difficult. Mitral annuloplasty was most commonly performed. The proportion of AFMR patients undergoing concomitant procedures for AF varied substantially.

CMR predictors of secondary moderate to severe mitral regurgitation and its additive prognostic role in previous myocardial infarction

BACKGROUND

We aimed to determine predictors and the additive prognostic role of moderate to severe (MS) ischemic mitral regurgitation (MR) in myocardial infarction (MI).

METHODS

Four hundred twenty-two patients with previous MI underwent cardiac magnetic resonance (CMR) imaging for the assessment of left ventricular (LV) ejection fraction (EF), end-diastolic (EDV) and end-systolic volume (ESV), sphericity index, wall motion score index (WMSI), and late gadolinium enhancement (LGE). Echocardiography was performed to assess MR.

RESULTS

Thirty-eight had from moderate to severe MR (MS-MR group) and 384 did not (No MS-MR group). The S-MR group had higher LV volumes, sphericity index, WMSI, and LGE extent, and lower LVEF. At univariate logistic regression analysis, dilated volumes, SI >0.43, dyskinesia of inferolateral wall, papillary muscle (PM)-LGE, and LGE extent >16% were associated with MS-MR. At multivariate analysis, only SI (OR=5.7) and PM-LGE (OR=3) were independently associated with MS-MR. Considering only patients without LV dilatation, only dyskinesia in the inferolateral wall was a predictor of MS-MR (OR 34.8). Thirty cardiac events (cardiac death, appropriate implantable cardioverter-defibrillator firing, and resuscitated cardiac arrest) occurred during a median follow-up of 1,276 days. After adjusting the prognostic variables at univariate analysis by age (>65 years) and selecting those that were significant (EDV > 95 ml/m², ESV >53 ml/m², EF <30%, WMSI >1.65, LGE >12%, S-MR), only WMSI >1.65 and MS-MR remained an independent predictor of cardiac events.

CONCLUSIONS

Increased WMSI and PM-LGE in the overall population and inferolateral dyskinesia in patients without ESV dilatation are predictors of MS-MR; MS-MR and elevated WMSI have independent negative prognostic value.

Optimal Quantification of Functional Mitral Regurgitation: Comparison of Volumetric and Proximal Isovelocity Surface Area Methods to Predict Outcome

Background

Effective orifice area (EOA) ≥0.2 cm² or regurgitant volume (Rvol) ≥30 mL predicts prognostic significance in functional mitral regurgitation (FMR). Both volumetric and proximal isovelocity surface area (PISA) methods enable calculation of these metrics. To determine their clinical value, we compared EOA and Rvol derived by volumetric and PISA quantitation upon outcome of patients with FMR.

Methods and Results

We examined the outcome of patients with left ventricular ejection fraction <35% and moderate to severe FMR. All had a complete echocardiogram including EOA and Rvol by both standard PISA and volumetric quantitation using total stroke volume calculated by left ventricular end‐diastolic volume×left ventricular ejection fraction and forward flow by Doppler method: EOA=Rvol/mitral regurgitation velocity time integral. Primary outcome was all‐cause mortality or heart transplantation. We examined 177 patients: mean left ventricular ejection fraction 25.2% and 34.5% with ischemic cardiomyopathy. Echo measurements were greater by PISA than volumetric quantitation: EOA (0.18 versus 0.11 cm²), Rvol (24.7 versus 16.9 mL), and regurgitant fraction (61 versus 37 %) respectively (all P value <0.001). During 3.6±2.3 years’ follow‐up, patients with EOA ≥0.2 cm² or Rvol ≥30 mL had a worse outcome than those with EOA <0.2 cm² or Rvol <30 mL only by volumetric (log rank P=0.003 and 0.004) but not PISA quantitation (log rank P=0.984 and 0.544), respectively.

Conclusions

Volumetric and PISA methods yield different measurements of EOA and Rvol in FMR; volumetric values exhibit greater prognostic significance. The echo method of quantifying FMR may affect the management of this disorder.

Mitral valve dysplasia in eight English Springer Spaniels

INTRODUCTION

To describe the signalment, physical examination, and echocardiographic findings of a series of English Springer Spaniels (ESSs) diagnosed with congenital mitral valve dysplasia (MD).

ANIMALS

Eight client-owned ESSs with congenital MD referred for murmur investigation and/or suspected congestive heart failure (CHF).

MATERIALS AND METHODS

Retrospective case series. Medical records and echocardiograms were reviewed to collect relevant data. Echocardiograms were assessed for the following abnormalities consistent with MD: thickened valve leaflets or leaflet tips, a 'hockey stick' appearance to the valve leaflets, abnormal length of one leaflet with respect to the other, and tethering of one or both leaflets to the papillary muscles.

RESULTS

All eight dogs showed the typical echocardiographic lesions associated with MD: thickened leaflet tips (5/8), 'hockey stick' appearance (5/8), elongated anterior leaflet (4/8), tethering of one or both leaflets (7/8). Seven of the eight dogs presented in CHF. Six of the eight dogs had left ventricular dilation in both systole and diastole. Two of the eight dogs had reduced systolic function as assessed by ejection fraction/fractional shortening; however end-systolic volume index was increased in 6/8 dogs. Two dogs subsequently developed atrial fibrillation.

CONCLUSIONS

Congenital MD should be considered in ESSs with a left-sided apical systolic murmur, particularly in younger dogs. The valve changes seen are similar to those reported in other breeds with MD (thickened leaflet tips, hockey stick appearance to open leaflet tips, abnormal leaflet tethering, abnormally shaped leaflets) and may result in marked remodeling and CHF.

Prognostic value of mitral valve tenting area in patients with functional mitral regurgitation

OBJECTIVES

Mitral valve (MV) repair in functional mitral regurgitation is still associated with suboptimal outcomes. Our goal was to determine whether the clinical outcome following MV repair correlates with preoperative tenting parameters.

METHODS

We retrospectively identified consecutive patients with functional mitral regurgitation who underwent an isolated MV annuloplasty during a 7-year period (2010-2016) from our institutional database. Preoperative tenting parameters (i.e. tenting height, coaptation length, tenting area, posterior mitral leaflet and anterior mitral leaflet angles and interpapillary muscle distance) were systematically measured. The primary end point was the composite of survival and freedom from adverse cardiac events. The follow-up protocol consisted of a structured clinical questionnaire and an analysis of the echocardiographic data.

RESULTS

A total of 240 patients (mean age 67.8 ± 9.8 years, 57% of men) were analysed. The overall 5-year survival rate for the whole study cohort was 74.7 ± 4.2%, and freedom from adverse cardiac events was 84.8 ± 3.4%. A tenting area ≥2.4 cm2 was identified as a cut-off value, independently predicting the composite primary study end point (hazard ratio 2.0; P = 0.03). Furthermore, a Kaplan-Meier analysis revealed a strong tendency towards worse 5-year outcomes in patients with a tenting area ≥2.4 cm2 (n = 153) versus patients with a tenting area <2.4 cm2 (n = 87) (65.3 ± 5.5% vs 77.1 ± 6.3%; P = 0.06).

CONCLUSIONS

MV annuloplasty is associated with acceptable clinical and echocardiographic outcomes in patients with functional mitral regurgitation 5 years postoperatively. A preoperative tenting area ≥2.4 cm2 showed a strong trend towards a worse 5-year survival rate and an increased risk of adverse cardiac events after an isolated MV annuloplasty.

Structural heart disease: the year in valvular and complex coronary intervention trials

The need for treatment strategies targeting complex structural heart and obstructive epicardial coronary artery disease (CAD) is rapidly growing. The demographics in referral centers has shifted to an older population with greater co-morbidities and higher risk. Indeed, nearly one quarter of patients in tertiary-care settings have moderate or severe valvular heart disease, and despite a decrease in overall CAD burden in the United States over the past two decades the prevalence of myocardial infarction remains high. The 2019 societal scientific sessions included novel research and landmark presentations on less invasive valvular and safer complex coronary interventions in the aforementioned populations, in hopes of improving patient outcomes and expanding treatment indications. Transcatheter aortic valve replacement (TAVR), percutaneous mitral and tricuspid valve therapy, and complex coronary interventions, were the focus of important clinical trials and registry data. Herein, we provide a select and concise review of the most pivotal studies presented.

Geometric description for the anatomy of the mitral valve: A review

The mitral valve is a complex anatomical structure whose physiological functioning relies on the biomechanical properties and structural integrity of its components. Their compromise can lead to mitral valve dysfunction, associated with morbidity and mortality. Therefore, a review on the morphometry of the mitral valve is crucial, more specifically on the importance of valve dimensions and shape for its function. This review initially provides a brief background on the anatomy and physiology of the mitral valve, followed by an analysis of the morphological information available. A characterisation of mathematical descriptions of several parts of the valve is performed and the impact of different dimensions and shape changes in disease is then outlined. Finally, a section regarding future directions and recommendations for the use of morphometric information in clinical analysis of the mitral valve is presented.

Echocardiography and Correction of Mitral Regurgitation: An Unbreakable Link

Background: Degenerative mitral valve (MV) disease causing mitral regurgitation (MR) is the most common organic valve pathology and is classified based on leaflet motion. MV repair is indicated as the preferred technique (Class I indication) when the results are expected to be durable. Therefore, a detailed and systematic evaluation of MV apparatus is pivotal in allowing the proper surgical planning, as well as the screening for trans catheter-based treatment when surgery is not indicated. Aim: The aim of the present review is to describe the crucial role of both Transthoracic Echocardiography (TTE) and Transesophageal Echocardiography (TEE) in the decisional process and the guidance of MV repair procedures. TTE is the main investigation and the first approach used to make diagnosis of MR, to assess the severity and to describe the underlying mechanism, while TEE, especially with 3D echocardiography, has been shown to be useful for clarifying complicated valvular anatomy, assessing the surgical result and detecting complications. The surgical treatment of MR takes advantage of ultrasound evaluation of MV apparatus at any stage of the process, thus making the link between surgery and echocardiography unbreakable throughout the perioperative phase.

[Clinical Course and Predictors of Ischemic Mitral Regurgitation in Patients with Myocardial Infarctions of Different Localizations]

PURPOSE

to assess the clinical course of ischemic mitral regurgitation (IMR) in patients with myocardial infarction of different localizations and reveal its mechanisms and predictors.

MATERIALS AND METHODS

We enrolled in this study patients with first inferoposterior myocardial infarction (IPMI) (n=77), and anteroseptal MI (ASMI) (n=79) revascularized within 12 hours after symptoms onset, as well as age, sex and weight matched healthy control subjects (n=50). Parameters of mitral structures and mitral annulus areas (MAA), left ventricular (LV) volumes (LVV) and sphericity index (SI), global (G) and segmental (S) longitudinal LV strain (GLS, SLS), papillary muscles (PM) LS (PMLS) and PM systolic dyssynchrony (PMSD) were measured by echocardiography on the 7th and 180th days of follow up.

RESULTS

On the 7th day of follow up IMR was diagnosed more frequently in IPMI vs. ASMI (42 vs. 28%, р&lt;0.001). In both groups patients with TIMI 0 flow before angioplasty had highest, while those with TIMI 3 flow - lowest incidence of IMR. Presence of IMR depended on collateral flow availability in vascular bed of infarct related artery. Wall motion abnormalities (WMA) of infarcted segments, MAA, posteromedial PM posterior displacement (PPMPD), SLS, PMLS, PMSD correlated with IMR in patients with IPMI on the 7th day of follow up. VLV, GLS and MAA correlated with IMR in patients with ASMI on the 7th day follow up. Patients with IPMI without IMR in 7th day did not develop IMR for 180 days of follow up while IMR developed in 19.3% of patients with ASMI without IMR at initial examination. Among patients with IPMI and ASMI 37.5% and 45.5%, respectively, of those with IMR at initial examination had no IMR after 180 days of follow up. Patients with IPMI more frequently had eccentric IMR than patients with ASMI (78 and 24%, respectively, p&lt;0.002). At examination after 6 months WMA, MAA, PMSD, PPMPD, SLS, PMLS, PMSD correlated with IMR in patients with IPMI, while VLV, AMA, PM apical displacement (PMAD), GLS and PMSD correlated with IMR in patients with ASMI. AMA, PMAD and PMSD were predictors of IMR in patients with MI of both localizations. In addition, in patients with ASMI VLV and SI were also predictors of IMR.

A Modified Echocardiographic Classification of Mitral Valve Regurgitation Mechanism: The Role of Three-dimensional Echocardiography

In this report, we provide an overview of a new, updated echocardiographic classification of mitral regurgitation mechanisms to provide a more comprehensive and detailed assessment of mitral valve disorders. This is relevant to modern mitral valve repair techniques, with special attention to the added value of 3D-echocardiography.

The unique mechanism of functional mitral regurgitation in acute myocardial infarction: a prospective dynamic 4D quantitative echocardiographic study

AIMS

Mechanisms of chronic ischaemic mitral regurgitation (IMR) are well-characterized by apically tethered leaflet caused by papillary muscles (PMs) displacement and adynamic mitral apparatus. We investigated the unique geometry and dynamics of the mitral apparatus in first acute myocardial infarction (MI) by using quantified 3D echocardiography.

METHODS AND RESULTS

We prospectively performed 3D echocardiography 2.3 ± 1.8 days after first MI, in 174 matched patients with (n = 87) and without IMR (n = 87). 3D echocardiography of left ventricular (LV) volumes and of mitral apparatus dynamics throughout cardiac cycle was quantified. Similar mitral quantification was obtained at chronic post-MI stage (n = 44). Mechanistically, acute IMR was associated with larger and flatter annulus (area 9.29 ± 1.74 cm2 vs. 8.57 ± 1.94 cm2, P = 0.002, saddle shape 12.7 ± 4.5% vs. 15.0 ± 4.6%, P = 0.001), and larger tenting (length 6.36 ± 1.78 mm vs. 5.60 ± 1.55 mm, P = 0.003) but vs. chronic MI, mitral apparatus displayed smaller alterations (all P < 0.01) and annular size, PM movement remained dynamic (all P < 0.01). Specific to acute IMR, without PM apical displacement (P > 0.70), greater separation (21.7 ± 4.9 mm vs. 20.0 ± 3.4 mm, P = 0.01), and widest angulation of PM (38.4 ± 6.2° for moderate vs. 33.5 ± 7.3° for mild vs. 31.4 ± 6.3° for no-IMR, P = 0.0009) wider vs. chronic MI (P < 0.01).

CONCLUSIONS

3D echocardiography of patients with first MI provides insights into unique 4D dynamics of the mitral apparatus in acute IMR. Mitral apparatus remained dynamic in acute MI and distinct IMR mechanism in acute MI is not PM displacement seen in chronic IMR but separation and excess angulation of PM deforming the mitral valve, probably because of sudden-onset regional wall motion abnormality without apparent global LV remodelling. This specific mechanism should be considered in novel therapeutic strategies for IMR complicating acute MI.

Valve Disease in Heart Failure: Secondary but Not Irrelevant

Secondary regurgitation caused by the remodeling and dysfunction of the left or right heart chamber may complicate heart failure, worsening both symptoms and prognosis. Outcome studies have shown that patients' prognosis worsened as the severity of secondary regurgitation increases. Imaging and more specifically echocardiography plays a central role for diagnosis and serial assessment of secondary regurgitation as well as for timing the intervention and guiding the procedure.

Risk of Ischemic Mitral Regurgitation Recurrence After Combined Valvular and Subvalvular Repair

BACKGROUND

Mitral valve repair (MVr) combined with papillary muscle approximation (PMA) may improve repair durability in severe ischemic mitral regurgitation (MR), when compared with MVr alone. We sought to identify preoperative transthoracic echocardiographic markers associated with MR recurrence after MVr with PMA.

METHODS

A post-hoc analysis was performed on patients with severe ischemic MR who underwent coronary artery bypass graft surgery with MVr with PMA in the papillary muscle approximation randomized trial. The PMA was performed utilizing a 4-mm polytetrafluoroethylene graft placed around the papillary muscles. Linear regression analyses and receiver-operating characteristic curves were used to identify echocardiographic variables and diagnostic models associated with recurrent MR.

RESULTS

There were 48 patients with a mean age of 63 ± 7 years, a left ventricular ejection fraction of 35% ± 5%, and a left ventricular end-diastolic diameter of 63 ± 3 mm. Of these, 37 patients had baseline and 5-year follow-up echocardiograms, with moderate-to-severe MR recurring in 27%. Linear regression analyses revealed associations between preoperative pulmonary artery systolic pressure (standardized beta coefficient, β = 0.49/mm Hg, p = 0.002), MV tenting area (β = 0.47/cm², p = 0.004), a symmetric MV tethering pattern (β = 0.44, p = 0.007), and left ventricular end-diastolic diameter (β = 0.37/mm, p = 0.02) with follow-up MR grade. The presence of both MV tenting area 3.1 cm² or greater (area under the curve 0.822) and left ventricular end-diastolic diameter of 64 mm or greater (area under the curve 0.801) was the most robust discriminative model for moderate-to-severe MR recurrence (specificity 92%, sensitivity 69%, area under the curve 0.804, p = 0.003).

CONCLUSIONS

In patients undergoing coronary artery bypass graft surgery with MVr plus PMA, the extent of baseline MV apparatus and left ventricle geometric remodeling identifies patients at increased risk for MR recurrence.

Correlation between echocardiographic severity of ischemic mitral valve regurgitation following acute myocardial infarction and its electrocardiographic location

Introduction: Ischemic mitral regurgitation (IMR) is common after acute myocardial infarction (AMI) which is associated with long-term cardiovascular mortality. Size, transmurality and location of the myocardial infarction (MI) has role on the development of IMR. In this study we evaluated the severity of IMR after different types of MI. Methods: One-hundred patients with the first AMI were recruited and according to echocardiographic findings were categorized to have moderate to severe IMR (case group, n=50) or trivial or no IMR (control group, n=50). Demographic and echocardiographic findings and MI location were compared between groups. Results: Case group compared to control group had significantly higher Killip class, more cases with left ventricular ejection fraction (LVEF) <30% and inferolateral STEMI. They had significantly higher left ventricular (LV) and right ventricular (RV) diastolic dysfunction. Mechanism of IMR was mono leaflet tethering in 88%, both leaflets tethering in 12% and ring dilatation in 62%. MR jet origin-direction was medial commisure-posterior in 66%, lateral commisure-anterior in 11 22% and both commisure-central direction in 12%. Conclusion: IMR is common after AMI, especially in cases with inferior MI. The echocardiographic findings are indicative of left ventricular remodeling and abnormality of mitral valve apparatus.

Advanced Imaging Techniques for Mitral Regurgitation

Mitral regurgitation (MR) is one of the most commonly encountered valvular lesions in clinical practice. MR can be either primary (degenerative) or secondary (functional) depending on the etiology of MR and the pathology of the mitral valve (MV). Echocardiography is the primary diagnostic tool for MR and is key in determining this etiology as well as MR severity. While clinicians usually turn to 2 Dimensional echocardiography as first-line imaging, 3 Dimensional echocardiography (3DE) has continually shown to be superior in terms of describing MV anatomy and pathology. This review article elaborates on 3DE techniques, modalities, and advances in software. Furthermore, the article demonstrates how 3DE has reformed MR evaluation and has played a vital role in determining patient management.

Mitral Valve and Subvalvular Repair for Secondary Mitral Regurgitation: Rationale and Clinical Outcomes of the Papillary Muscle Sling

Secondary mitral regurgitation (MR) is a common finding in patients with dilated cardiomyopathy, and it is associated with poor outcomes. It is the result of incomplete systolic closure of the mitral valve (MV) as a consequence of left ventricular dilatation, papillary muscle displacement with impaired systolic shortening, and mitral leaflet tethering. MV surgery may be performed in cases of significant secondary MR despite guideline-directed medical therapy. However, MV repair, which is most commonly performed with an undersized ring annuloplasty, is associated with a 30-60% recurrence of moderate or greater MR at mid-term follow-up. To improve MV repair durability, several adjunctive subvalvular procedures have been proposed, one of which is the addition of papillary muscle approximation utilizing a papillary muscle sling. Recent studies comparing the outcomes of a conventional undersized ring annuloplasty with a MV repair utilizing a papillary muscle sling have reported a significant reduction in recurrent moderate or severe MR, greater left ventricular reverse remodeling, and improved MV apparatus geometry with the addition of the papillary muscle sling. We present a comprehensive review of the pathophysiology of secondary MR, and the rationale and clinical outcomes of MV repair with papillary muscle sling placement for the treatment of secondary MR.

Ischemic Mitral Regurgitation: Repair, Replacement or Nothing

The treatment strategy for ischemic mitral regurgitation (MR) continues to evolve with the completion of multicenter trials and the advancement of surgical and percutaneous interventional techniques. This review defines ischemic MR, outlines key clinical trials that assess surgical and interventional approaches, and reports the main elements of recent national guidelines for decision making in treatment of ischemic MR. New findings in percutaneous mitral valve repair and replacement for ischemic MR will also be described. Effective perioperative care of patients with ischemic MR requires clinicians to be well versed in the most up-to-date recommendations and emerging technological developments.

Contemporary Management of Ischemic Mitral Regurgitation: A Review

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

Functional Mitral Regurgitation: Imaging Insights, Clinical Outcomes and Surgical Principles

Functional mitral regurgitation (MR; FMR) is the most common type of MR and its development is associated with increased morbidity and mortality. Leaflet tethering with apical shift of the papillary muscle due to adverse left ventricular remodeling and loss of normal leaflet coaptation is the principal mechanism of FMR. Echocardiography plays a central role in the assessment of the FMR. The development of 3D echocardiography has allowed for assessment of the geometric changes of mitral valve morphology and spatial relationship with the left ventricle that accompanies FMR. 2D/3D echocardiographic findings, clinical outcomes of FMR are reviewed and role of surgical intervention is discussed.

Surgical Treatment of Ischemic Mitral Regurgitation: Valve Repair Versus Replacement

PURPOSE OF REVIEW

Ischemic mitral regurgitation (MR), which occurs in about 20-30% patients with a prior myocardial infarction, is associated with worsening heart failure and an increase in cardiovascular mortality. It should be treated surgically if certain hemodynamic severity criteria are met and in patients who continue to experience symptoms of heart failure despite optimal medical therapy. However, current guidelines do not suggest which of the available approaches to mitral valve surgery-mitral valve (MV) repair or replacement (MVR) is superior for this indication. While MV repair is reported to confer improved survival, MVR may provide higher rates of freedom from recurrent MR. This article attempts to provide the reader with a comprehensive review and comparison of current techniques of mitral valve surgery in patients with severe ischemic MR.

RECENT FINDINGS

The first randomized trial to compare MV repair versus MVR in patients with severe ischemic MR, the Cardiothoracic Surgical Trials Network (CTSN) trial, was recently concluded and reported no significant difference in the primary outcome of left ventricular end systolic volume index between the two approaches at either 1- or 2-year follow-ups. Data comparing approaches of MV repair and MVR for ischemic MR is largely limited to small, non-randomized retrospective trials. The only randomized trial data to examine this issue suggested no difference in mortality with either MVR or MV repair; however, MVR was shown to be consistently associated with higher rates of MR recurrence. Certain echocardiographic features have been reported to predict poor outcomes with MVR and may help refine the selection of the surgical approach in the individual patient.

Mitral valve repair and subvalvular intervention for secondary mitral regurgitation: a systematic review and meta-analysis of randomized controlled and propensity matched studies

BACKGROUND

Combining a ring annuloplasty (Ring) with a mitral subvalvular intervention (Ring + subvalvular) in patients with secondary mitral regurgitation (MR) may improve mitral valve (MV) repair durability. However, the outcomes of this strategy compared with a Ring only, have not been clearly defined.

METHODS

A systematic review and meta-analysis was performed utilizing randomized controlled and propensity matched studies which compared a Ring + subvalvular versus Ring MV repair for the treatment of secondary MR. Risk ratio (RR), weighted mean difference (MD), and the 95% confidence interval (CI) were calculated by the Mantel-Haenszel and inverse-variance methods, for clinical outcomes and echocardiographic measures of follow-up MR, left ventricular (LV) reverse remodeling, and MV apparatus geometry.

RESULTS

Five studies were identified, with a total of 397 patients. Baseline characteristics were similar between groups, and all patients had moderate to severe secondary MR, with the vast majority in the setting of ischemic cardiomyopathy. A Ring + subvalvular repair consisted of papillary muscle approximation (n=2), papillary muscle relocation (n=2), or secondary chordal cutting (n=1). Follow-up ranged from 10.1 (mean range =0.25-42) to 69 [interquartile range (IQR) =23-82] months. When compared with Ring only at last follow-up, a Ring + subvalvular MV repair was associated with: (I) a smaller MR grade (MD =-0.44, 95% CI -0.69 to -0.19; P=0.0005); (II) a reduced risk of moderate or greater recurrent MR (RR =0.43, 95% CI, 0.27-0.66; P=0.0002); (III) a smaller mean LV end-diastolic diameter (MD =-3.56 mm, 95% CI -5.40 to -1.73; P=0.0001) and a greater ejection fraction (MD =2.64%, 95% CI, 0.13-5.15; P=0.04); and, (IV) an improved MV apparatus geometry. There were no differences in operative mortality, post-operative morbidity, or follow-up survival between surgical approaches.

CONCLUSIONS

When compared with Ring only, a Ring + subvalvular MV repair is associated with greater LV reverse remodeling and systolic function, less recurrence of moderate or greater MR, and an improved geometry of the MV apparatus at short and mid-term follow-up.

The role of papillary muscle approximation in mitral valve repair for the treatment of secondary mitral regurgitation

Secondary mitral regurgitation (MR) is present in up to half of patients with dilated cardiomyopathy, and is associated with a poor prognosis. It primarily results from progressive left ventricular remodelling, papillary muscle displacement and tethering of the mitral valve leaflets. Mitral valve repair with an undersized ring annuloplasty is the reparative procedure of choice in the treatment of secondary MR. However, this technique is associated with a 30-60% incidence of recurrent moderate or greater MR at mid-term follow-up, which results in progressive deterioration of left ventricular function and increased morbidity. Combined mitral valve repair and papillary muscle approximation has been applied in order to address both the annular and subvalvular dysfunction that coexist in secondary MR, which include graft and suture-based techniques. Herein, we provide a systematic review of the published literature regarding the technical aspects, clinical application, and outcomes of mitral valve repair with combined ring annuloplasty and papillary muscle approximation for the treatment of secondary MR.

Regional Heterogeneity in the Mitral Valve Apparatus in Patients With Ischemic Mitral Regurgitation

BACKGROUND

Apical displacement of the coaptation point of the mitral valve (MV) in response to ischemic mitral regurgitation (IMR) represents remodeling of the MV apparatus. Whereas it implies chronicity, it lacks specificity in discriminating normal from a significantly remodeled MV apparatus. Regional aspects of MV remodeling have shown superior value over global remodeling in predicting recurrence after MV repair for IMR. Quite possibly, presence of specific regional changes in MV geometry that are unique to chronic IMR patients could also be used to diagnose the presence and track progression of remodeling. Knowledge of these changes in MV apparatus in patients with IMR can possibly be used to identify patients for surgical intervention before irreversible remodeling occurs.

METHODS

Three-dimensional transesophageal echocardiographic data were collected from patients who underwent MV surgery for IMR (IMR group, n = 66), and from patients with normal valvular and biventricular function (control group, n = 10). The acquired data of the MV were geometrically analyzed to make regional comparisons between the IMR and the control group to identify measurements that reliably differentiate normal from remodeled MVs.

RESULTS

Lengthening of the middle potion of the anterior annulus (A2 regional perimeter: 11.149 mm versus 9.798 mm, p = 0.0041), larger nonplanarity angle (147.985 versus 140.720 degrees, p = 0.0459), and increased tenting angle of the posteromedial scallop of the posterior leaflet (P3 tenting angle: 44.354 versus 40.461 degrees, p = 0.0435) were sufficient in differentiating between IMR and the control group.

CONCLUSIONS

Specific three-dimensional changes in MV geometry can be used to reliably identify a significantly remodeled valve apparatus.

Outcomes of ischaemic mitral regurgitation in anterior versus inferior ST elevation myocardial infarction

Background

Ischaemic mitral regurgitation (IMR) is a detrimental complication of ST elevation myocardial infarction (STEMI).

Objective

We sought to determine patient characteristics and outcomes of patients with IMR with focus on anterior or inferior location of STEMI.

Methods

All patients presenting with STEMI complicated by IMR to our centre who underwent primary percutaneous coronary intervention within the first 12 hours of presentation from 1995 to 2014 were included. IMR was graded from 1+ to 4+ within 3 days of index myocardial infarction by echocardiography, divided into 2 groups based on infarct location and outcomes were compared.

Results

Overall, 805 patients were included. There were 302 (17.8%) patients with mitral regurgitation (MR) out of the 1700 patients with anterior STEMI while 503 (21.8%) had MR out of the 2305 patients with inferior STEMI. There was no significant difference between both groups in comorbidities, clinical presentation or door-to-balloon time (DBT; median 104 vs 106 min, p=0.5). 30-day and 1-year mortality were higher in anterior STEMI compared with inferior STEMI (14.9% vs 6.8% and 26.4% vs 14.3%, respectively, p<0.001 both), as well as 5-year mortality (39.7% vs 24.8%, p<0.01). When analysis was performed for each grade of IMR, anterior was associated with worse outcomes in every grade. On multivariate cox survival analysis, after adjustment for age, gender, comorbidities, grade of IMR, ejection fraction and DBT, anterior STEMI was still associated with worse outcomes (HR 1.62 (95% CI 1.23 to 2.12), p<0.001).

Conclusions

Although IMR occurs more frequently with inferior infarction, outcomes are worse following anterior infarction.

Dynamic changes in the ischemic mitral annulus: Implications for ring sizing

OBJECTIVES

Contrary to the rest of the mitral annulus, inter-trigonal distance is known to be relatively less dynamic during the cardiac cycle. Therefore, intertrigonal distance is considered a suitable benchmark for annuloplasty ring sizing during mitral valve (MV) surgery. The entire mitral annulus dilates and flattens in patients with ischemic mitral regurgitation (IMR). It is assumed that the fibrous trigone of the heart and the intertrigonal distance does not dilate. In this study, we sought to demonstrate the changes in mitral annular geometry in patients with IMR and specifically analyze the changes in intertrigonal distance during the cardiac cycle.

METHODS

Intraoperative three-dimensional transesophageal echocardiographic data obtained from 26 patients with normal MVs undergoing nonvalvular cardiac surgery and 36 patients with IMR undergoing valve repair were dynamically analyzed using Philips Qlab ® software.

RESULTS

Overall, regurgitant valves were larger in area and less dynamic than normal valves. Both normal and regurgitant groups displayed a significant change in annular area (AA) during the cardiac cycle (P < 0.01 and P < 0.05, respectively). Anteroposterior and anterolateral-posteromedial diameters and inter-trigonal distance increased through systole (P < 0.05 for all) in accordance with the AAs in both groups. However, inter-trigonal distance showed the least percentage change across the cardiac cycle and its reduced dynamism was validated in both cohorts (P > 0.05).

CONCLUSIONS

Annular dimensions in regurgitant valves are dynamic and can be measured feasibly and accurately using echocardiography. The echocardiographically identified inter-trigonal distance does not change significantly during the cardiac cycle.

Left Ventricular Mechanics in Functional Ischemic Mitral Regurgitation in Acute Inferoposterior Myocardial Infarction

Ischemic mitral regurgitation (MR) is an established adverse prognostic factor after myocardial infarction (MI). Functional ischemic mitral regurgitation in acute phase of MI remains under‐investigated due to its often transient and dynamic nature. We aimed to assess left ventricular (LV) mechanics by speckle‐tracking echocardiography in acute inferoposterior MI and ischemic mitral regurgitation (MR).

Methods

Sixty‐nine patients with no structural cardiac valve abnormalities and first acute inferoposterior MI were prospectively enrolled into the study. Two‐dimensional transthoracic echocardiography for regional myocardial function and valve assessment was performed within 48 hours of presentation after reperfusion therapy (percutaneous coronary intervention). Based on degree of MR, patients were divided into no significant MR (NMR) group (N = 34, with no or mild (grade 0–I) MR) and ischemic MR (IMR) group (N = 35, with grade ≥2 MR). Thirty‐five age‐ and gender‐matched healthy individuals served as a normal reference group. Offline 2D speckle tracking analysis was performed with GE EchoPAC software.

Results

LV ejection fraction and longitudinal myocardial deformation parameters were significantly better in healthy subjects, but did not differ between both study groups. All circumferential myocardial deformation parameters were significantly worse in IMR group compared to healthy subjects and NMR group. Global, basal, and mid‐ventricular radial strain was significantly lower in IMR group compared to both—healthy subjects and NMR group.

Conclusion

Ischemic mitral regurgitation in acute inferoposterior MI is associated with worse radial and circumferential LV deformation parameters assessed by 2D speckle tracking echocardiography.

Percutaneous Coronary Intervention Followed by Minimally Invasive Mitral Valve Surgery in Ischemic Mitral Regurgitation

OBJECTIVE

The optimal treatment strategy in patients with coronary artery disease and ischemic mitral regurgitation (IMR) remains controversial. A staged approach of percutaneous coronary intervention (PCI) followed by minimally invasive valve surgery, rather than combined median sternotomy coronary artery bypass and valve surgery, may be a viable alternative.

METHODS

We retrospectively evaluated 31 consecutive patients with coronary artery disease and severe IMR who underwent a staged procedure at our institution between February 2009 and April 2014.

RESULTS

The mean ± SD age, preoperative left ventricular ejection fraction, and mitral regurgitation grade were 72 ± 7 years, 35% ± 11%, and 3.6 ± 0.6, respectively. The mean ± SD Society of Thoracic Surgeons-predicted mortality score was 5.1% ± 4.2%. Percutaneous coronary intervention was performed for 1- and 2-vessel disease in 22 patients (71%) and 9 patients (29%), respectively, with 23 patients (74%) having drug-eluting stents placed. Minimally invasive valve surgery was performed within a median of 36 days after PCI, with 61% of the patients being on dual antiplatelet therapy. Postoperatively, there was 1 case of acute kidney injury, 1 case of reoperation for bleeding, and no cerebrovascular accidents. The 30-day mortality was 3%. The median total hospital length of stay was 8 days (interquartile range, 7-10). At a mean ± SD follow-up of 2.4 ± 1.6 years, 2 patients required PCI for target-vessel revascularization. Actuarial survival at 1 and 5 years was 84% and 80%, respectively.

CONCLUSIONS

A staged approach in patients with coronary artery disease and IMR can be performed with a low perioperative morbidity and good midterm survival.