American Society of Echocardiography Algorithm for Degenerative Mitral Regurgitation: Comparison With CMR

ObjectivesThe purpose of this study was to compare the American Society of Echocardiography (ASE) algorithm for assessing mitral regurgitation (MR) to cardiac magnetic resonance (CMR) and left ventricular (LV) remodeling following mitral intervention.BackgroundThe ASE recommends integrating multiple echocardiographic parameters for assessing MR. The ASE guidelines include an algorithm that weighs the parameters and highlights those considered indicative of definitely mild or definitely severe MR.MethodsWe prospectively enrolled 152 (age 62 ± 13 years; 59% male) patients with degenerative MR who underwent ASE algorithm-guided echocardiographic and CMR grading of MR severity. Using the ASE algorithm, patients were graded as definitely mild, grade I, grade II, grade III, grade IV, or definitely severe MR. CMR MR volume was graded as mild (<30 mL), grade II moderate (30-44 mL), grade III moderate (45-59 mL), or severe (≥60 mL). A subgroup of 63 patients underwent successful mitral intervention, of whom 48 had postintervention CMR.ResultsOnly 52% of patients with definitely severe MR by the ASE algorithm had severe MR by CMR, and 10% had mild MR by CMR. There was an increase in post mitral intervention LV reverse remodeling with worsening MR severity using CMR (P < 0.0001) but not the ASE algorithm (P = 0.07). Severe MR by CMR was an independent predictor of post mitral intervention LV reverse remodeling and definitely severe MR by the ASE algorithm was not.ConclusionsIn patients with degenerative MR, agreement between CMR and the ASE algorithm was suboptimal. Severe MR by CMR was an independent predictor of post mitral intervention LV reverse remodeling, whereas definitely severe MR by the ASE algorithm was not. These findings suggest an important role for CMR in surgical decision making in degenerative MR. (Comparison Study of Echocardiography and Cardiovascular Magnetic Resonance Imaging in the Assessment of Mitral and Aortic Regurgitation; NCT04038879)     

Regional Replacement and Diffuse Interstitial Fibrosis in Aortic Regurgitation: Prognostic Implications From Cardiac Magnetic Resonance

ObjectivesThis study used cardiac magnetic resonance (CMR) to assess left ventricular (LV) remodeling in chronic aortic regurgitation (AR) to identify both forms of myocardial fibrosis and examine its association with clinical outcomes.BackgroundChronic AR leads to LV remodeling, which is associated with 2 forms of myocardial fibrosis: regional replacement fibrosis that is directly imaged by late gadolinium enhancement (LGE) CMR; and diffuse interstitial fibrosis, which can be inferred by T1 mapping techniques.MethodsPatients with chronic AR who were undergoing contrast CMR with T1 mapping for valve assessment from 2011 to 2018 were enrolled. Patients with a confounding etiology of myocardial fibrosis were excluded. In addition to quantification of AR severity and LV volumetrics, LGE and T1 mapping pre- and post-contrast were performed to measure extracellular volume (ECV) and indexed ECV (iECV). Patients were followed up longitudinally to assess for the composite event of death and the need for aortic valve replacement.ResultsA total of 177 patients with isolated chronic AR were included (66% males, median age 58 years [IQR: 47.0-68.0 years]) with a median follow up of 2.5 years (IQR: 1.07-3.56 years). The iECV significantly increased with AR severity (P < 0.001), whereas ECV and replacement fibrosis did not (P = NS). On multivariate analysis, iECV remained associated with the composite event (P = 0.01). On Kaplan-Meier analysis stratified by AR regurgitant fraction (RF) and iECV, patients with AR RF severity ≥30% and iECV ≥24 mL/m² demonstrated the highest event rate.ConclusionsAmong CMR biomarkers of fibrosis, iECV was more closely associated than replacement fibrosis or ECV with survival free of aortic valve replacement.     

Impact of Mitral Regurgitation Severity and Left Ventricular Remodeling on Outcome After MitraClip Implantation: Results From the Mitra-FR Trial

ObjectivesThis study aimed to identify a subset of patients based on echocardiographic parameters who might have benefited from transcatheter correction using the MitraClip system in the MITRA-FR (Percutaneous Repair with the MitraClip Device for Severe Functional/Secondary Mitral Regurgitation) trial.BackgroundIt has been suggested that differences in the degree of mitral regurgitation (MR) and left ventricular (LV) remodeling may explain the conflicting results between the MITRA-FR and the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation) trials.MethodsIn a post hoc analysis, we evaluated the interaction between the intervention and subsets of patients defined based on MR severity (effective regurgitant orifice [ERO], regurgitant volume [RVOL] and regurgitant fraction [RF]), LV remodeling (end-diastolic and end-systolic diameters and volumes) and combination of these parameters with respect to the composite of death from any cause or unplanned hospitalization for heart failure at 24 months.ResultsWe observed a neutral impact of the intervention in subsets with the highest MR degree (ERO ≥30 mm², RVOL ≥45 ml or RF ≥50%) as in patients with milder MR degree. The same was seen in subsets with the milder LV remodeling using either diastolic or systolic diameters or volumes. When parameters of MR severity and LV remodeling were combined, there was still no benefit of the intervention including in the subset of patients with an ERO/end-diastolic volume ratio ≥ 0.15 despite similar ERO and LV end-diastolic volume compared with COAPT patients.ConclusionsIn the MITRA-FR trial, we could not identify a subset of patients defined based on the degree of the regurgitation, LV remodeling or on their combination, including those deemed as having disproportionate MR, that might have benefited from transcatheter correction using the MitraClip system. (Multicentre Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary Mitral Regurgitation [MITRA-FR]; NCT01920698)     

Attenuated Mitral Leaflet Enlargement Contributes to Functional Mitral Regurgitation After Myocardial Infarction

BackgroundMitral leaflet enlargement has been identified as an adaptive mechanism to prevent mitral regurgitation in dilated left ventricles (LVs) caused by chronic aortic regurgitation (AR). This enlargement is deficient in patients with functional mitral regurgitation, which remains frequent in the population with ischemic cardiomyopathy. Maladaptive fibrotic changes have been identified in post-myocardial infarction (MI) mitral valves. It is unknown if these changes can interfere with valve growth and whether they are present in other valves.ObjectivesThis study sought to test the hypothesis that MI impairs leaflet growth, seen in AR, and induces fibrotic changes in mitral and tricuspid valves.MethodsSheep models of AR, AR + MI, and controls were followed for 90 days. Cardiac magnetic resonance, echocardiography, and computed tomography were performed at baseline and 90 days to assess LV volume, LV function, mitral regurgitation and mitral leaflet size. Histopathology and molecular analyses were performed in excised valves.ResultsBoth experimental groups developed similar LV dilatation and dysfunction. At 90 days, mitral valve leaflet size was smaller in the AR + MI group (12.8 ± 1.3 cm² vs. 15.1 ± 1.6 cm², p = 0.03). Mitral regurgitant fraction was 4% ± 7% in the AR group versus 19% ± 10% in the AR + MI group (p = 0.02). AR + MI leaflets were thicker compared with AR and control valves. Increased expression of extracellular matrix remodeling genes was found in both the mitral and tricuspid leaflets in the AR + MI group.ConclusionsIn these animal models of AR, the presence of MI was associated with impaired adaptive valve growth and more functional mitral regurgitation, despite similar LV size and function. More pronounced extracellular remodeling was observed in mitral and tricuspid leaflets, suggesting systemic valvular remodeling after MI.     

Impact of Myocardial Scar on Prognostic Implication of Secondary Mitral Regurgitation in Heart Failure

ObjectivesThe objective of the present study was to use cardiovascular magnetic resonance (CMR) to examine the natural history of secondary MR severity and the implication of left ventricular (LV) scar on its prognostic significance.BackgroundThere is a need for further understanding of the prognostic implication of secondary mitral regurgitation (MR) given the heterogeneous findings of the 2 recent randomized trials on percutaneous mitral intervention in patients with secondary MR.MethodsPatients with heart failure were enrolled into a prospective observational registry between 2008 and 2019. Outcomes were a composite of all-cause death, heart transplantation, or LV assist device implantation at follow-up. CMR was used to quantify the mitral regurgitation volume and mitral regurgitation fraction (MRF) along with scar burden utilizing late gadolinium enhancement. Patients were categorized into 4 subgroups based on presence and tertiles of scar extent: no scar, limited scar (scar burden 1% to 4%), intermediate scar (scar burden 5% to 20%), and extensive scar (scar burden >20%).ResultsAmong patients (n = 441) included in the study (age 59 ± 14 years, 43% with ischemic etiology), 85 (19%) experienced an adverse event. MRF ≥30% was associated with increased risk of events among the study group (hazard ratio: 1.74; 95% confidence interval: 1.10 to 2.76; p = 0.02). When stratified by presence or absence of scar, MRF ≥30% was associated with events only among patients with scar (hazard ratio: 1.67; 95% confidence interval: 1.02 to 2.76; p = 0.04) but not among patients without scar. On further classification of patients with scar, the prognostic significance of secondary MR was observed primarily among patients with intermediate scar burden.ConclusionsThe natural history of secondary MR is complex, and outcomes are affected by severity of MR and vary depending upon the extent of scar. (DeBakey Cardiovascular Magnetic Resonance Study [DEBAKEY-CMR]; NCT04281823)     

Extracellular Volume in Primary Mitral Regurgitation

ObjectivesThis study used cardiovascular magnetic resonance (CMR) to evaluate whether elevated extracellular volume (ECV) was associated with mitral valve prolapse (MVP) or if elevated ECV was a consequence of remodeling independent of primary mitral regurgitation (MR) etiology.BackgroundReplacement fibrosis in primary MR is more prevalent in MVP; however, data on ECV as a surrogate for diffuse interstitial fibrosis in primary MR are limited.MethodsPatients with chronic primary MR underwent comprehensive CMR phenotyping and were stratified into an MVP cohort (>2 mm leaflet displacement on a 3-chamber cine CMR) and a non-MVP cohort. Factors associated with ECV and replacement fibrosis were assessed. The association of ECV and symptoms related to MR and clinical events (mitral surgery and cardiovascular death) was ascertained.ResultsA total of 424 patients with primary MR (229 with MVP and 195 non-MVP) were enrolled. Replacement fibrosis was more prevalent in the MVP cohort (34.1% vs. 6.7%; p < 0.001), with bi-leaflet MVP having the strongest association with replacement fibrosis (odds ratio: 10.5; p < 0.001). ECV increased with MR severity in a similar fashion for both MVP and non-MVP cohorts and was associated with MR severity but not MVP on multivariable analysis. Elevated ECV was independently associated with symptoms related to MR and clinical events.ConclusionsAlthough replacement fibrosis was more prevalent in MVP, diffuse interstitial fibrosis as inferred by ECV was associated with MR severity, regardless of primary MR etiology. ECV was independently associated with symptoms related to MR and clinical events. (DeBakey Cardiovascular Magnetic Resonance Study [DEBAKEY-CMR]; NCT04281823)     

Relationship of Mechanical Dyssynchrony and LV Remodeling With Improvement of Mitral Regurgitation After CRT

ObjectivesThe aim of this study was to explore the association between mechanical dyssynchrony of the left ventricle before cardiac resynchronization therapy (CRT) and improvement of mitral regurgitation (MR) after CRT.BackgroundMR is very frequent among patients with dilated cardiomyopathy and conduction delay.MethodsEchocardiograms (pre-CRT and 12 ± 3.8 months thereafter) of 314 patients with dilated cardiomyopathy and any degree of MR, who underwent CRT device implantation according to guidelines, were analyzed. Left ventricular (LV) mechanical dyssynchrony was assessed by apical rocking (ApRock) and septal flash (SF), while MR severity was graded from I to IV on the basis of vena contracta width, regurgitation jet size, and proximal isovelocity surface area.ResultsAt baseline, 30% of patients presented with severe MR (grade III or IV). In 62% of patients, MR decreased after CRT, and these patients more frequently had left bundle branch block, had more severe MR, had more dilated left ventricles, had lower ejection fractions, and more often had ApRock and SF. Reverse remodeling was more frequent among patients with MR reduction (ΔLV end-systolic volume ?35.5% ± 27.2% vs ?4.1% ± 33.2%; P < 0.001). In a multivariable logistic stepwise regression, only ApRock (odds ratio [OR]: 3.8; 95% CI: 1.7-8.5; P = 0.001), SF (OR: 3.6; 95% CI: 1.6-7.9; P = 0.002), and baseline MR (OR: 1.4; 95% CI: 1.0-1.9; P = 0.046) remained significantly associated with MR reduction.ConclusionsApRock, SF, and severity of MR at baseline are strongly associated with MR reduction after CRT, while LV reverse remodeling is its underlying mechanism. Therefore, in patients with heart failure with LV dyssynchrony on optimal medical treatment, CRT should be the primary treatment attempt for relevant MR.     

Outcomes After Transcatheter Edge-to-Edge Mitral Valve Repair According to Mitral Regurgitation Etiology and Cardiac Remodeling

BackgroundTranscatheter edge-to-edge repair (TEER) has been increasingly used for selected patients with mitral regurgitation (MR), but limited data are available regarding clinical outcomes in patients with varied etiology and mechanism of MR.ObjectivesThe aim of this study was to evaluate the outcomes of TEER according to etiology and left ventricular (LV) and left atrial remodeling.MethodsConsecutive patients who underwent TEER between 2007 and 2020 were included in the analysis. Among patients with functional MR (FMR), those with predominant LV remodeling were classified as having ventricular FMR (v-FMR), whereas those without LV remodeling but predominant left atrial remodeling were classified as having atrial FMR (a-FMR). The primary outcome was a composite of all-cause mortality and heart failure hospitalization at 2 years and was compared among patients with degenerative MR (DMR), a-FMR, and v-FMR.ResultsA total of 1,044 patients (11% with a-FMR, 48% with v-FMR, and 41% with DMR) with a mean Society of Thoracic Surgeons score of 8.6 ± 7.8 underwent TEER. Patients with a-FMR had higher rates of atrial fibrillation and severe tricuspid regurgitation with larger left and right atria, whereas patients with v-FMR had lower LV ejection fractions with larger LV dimensions. Residual MR more than moderate at discharge was not significantly different among the 3 groups (5.2% vs 3.2% vs 2.6%; P = 0.37). Compared with patients with DMR, 2-year event rates of the primary outcome were significantly higher in patients with a-FMR and v-FMR (21.6% vs 31.5% vs 42.3%; log-rank P < 0.001).ConclusionsDespite excellent procedural outcomes, patients with a-FMR and v-FMR had worse clinical outcomes compared with those with DMR.     

Risk Associated With Valvular Regurgitation During Pregnancy

BackgroundPregnancies in women with regurgitant valve lesions are generally considered low risk, but this has not been well studied.ObjectivesThis study determined the frequency of adverse cardiac events (CEs) in pregnant women with moderate or severe regurgitant valve lesions.MethodsMaternal and fetal outcomes in women with moderate or severe chronic valve regurgitation enrolled in a prospective multicenter study on pregnancy outcomes were examined. Adverse CEs included heart failure, sustained arrhythmias, cardiac arrest, or death. A multivariate logistic regression model was used to identify determinants of CEs in women at the highest risk.ResultsOutcomes of 430 pregnancies in women with moderate or severe regurgitant lesions were examined: 145 with mitral regurgitation (MR), 101 with pulmonary regurgitation (PR), 71 with multivalve disease, 73 with tricuspid regurgitation (TR), and 40 with aortic regurgitation (AR). Most women had associated congenital or acquired heart disease. Adverse CEs occurred in 13% of pregnancies: 27% of pregnancies with multivalve disease; 15% with MR; 15% with TR; 5% with AR; and 3% with PR. Maternal mortality was rare. In women with MR, TR, or multivalve disease (n = 289), left ventricular systolic dysfunction (p = 0.001), pulmonary hypertension (p = 0.005), and cardiac events before pregnancy (p < 0.001) were important determinants of CEs during pregnancy.ConclusionsWomen with AR and PR are at low risk for cardiac complications during pregnancy. While many women with MR, TR, and multivalve regurgitation do well during pregnancy, additional clinical variables help stratify those at highest risk. This new information will enhance the quality and precision of preconception counseling and pregnancy planning.     

Comparison of Echocardiographic Assessment of Tricuspid Regurgitation Against Cardiovascular Magnetic Resonance

ObjectivesThe aim of this study was to compare echocardiographic methods of determining tricuspid regurgitation (TR) severity against TR regurgitant volume (TR_RV) by cardiovascular magnetic resonance (CMR).BackgroundTR is usually assessed using echocardiography, but it is not known how this compares with quantitative measurements of TR severity by CMR.MethodsEchocardiographic and CMR methods were compared in 337 patients. Echocardiographic methods included jet size, hepatic vein flow, inferior vena cava diameter, percentage change in inferior vena cava diameter with inspiration, right atrial end-systolic area and volume, right ventricular end-diastolic and end-systolic areas and fractional area change, vena contracta diameter, effective regurgitant orifice area, and TR_RV using the proximal isovelocity surface area method. TRRV by CMR was calculated as the difference between right ventricular end-diastolic and end-systolic volumes and systolic flow through the pulmonic valve.ResultsEchocardiographic parameters of TR severity had variable accuracy against TR_RV by CMR (area under the curve range 0.58 for jet area/right atrial end-systolic area to 0.79 for hepatic vein flow). A multiparametric approach to assessing TR severity according to the 2017 American Society of Echocardiography criteria had 65% agreement with TR severity by CMR. A hierarchal approach based on signals with higher feasibility and accuracy against CMR had 68% agreement, without missing cases of severe TR by CMR. Agreement with CMR by the hierarchal approach was higher than that by the 2017 American Society of Echocardiography guidelines (p = 0.016).ConclusionsSeveral individual echocardiographic parameters of TR severity have satisfactory accuracy against TR_RV by CMR. A multiparametric hierarchal approach resulted in 68% agreement with CMR and 100% agreement when a 1-grade difference in TR severity is considered acceptable.     

Regurgitant Volume/Left Ventricular End-Diastolic Volume Ratio: Prognostic Value in Patients With Secondary Mitral Regurgitation

ObjectivesThe purpose of this study was to investigate the prognostic implications of the ratio of mitral regurgitant volume (RVol) to left ventricular (LV) end-diastolic volume (EDV) in patients with significant secondary mitral regurgitation (MR).BackgroundQuantification of secondary MR remains challenging, and its severity can be over- or underestimated when using the proximal isovelocity surface area method, which does not take LV volume into account. This limitation can be addressed by normalizing mitral RVol to LVEDV.MethodsA total of 379 patients (mean age 67 ± 11 years; 63% male) with significant (moderate and severe) secondary MR were divided into 2 groups according to the RVol/EDV ratio: RVol/EDV ≥20% (greater MR/smaller EDV) and <20% (smaller MR/larger EDV). The primary endpoint was all-cause mortality.ResultsDuring median (interquartile range) follow-up of 50 (26 to 94) months, 199 (52.5%) patients died. When considering patients receiving medical therapy only, patients with RVol/EDV ratio ≥20% tended to have higher mortality rates than those with RVol/EDV ratio <20% (5-year estimated rates 24.1% vs. 18.4%, respectively; p = 0.077). Conversely, when considering the entire follow-up period including mitral valve interventions, patients with a higher RVol/EDV ratio (≥20%) had lower rates of all-cause mortality compared with patients with RVol/EDV ratio <20% (5-year estimated rates 39.0% vs. 44.8%, respectively; p = 0.018). On multivariable analysis, higher RVol/EDV ratio (per 5% increment as a continuous variable) was independently associated with lower all-cause mortality (0.93; p = 0.023).ConclusionsIn patients with significant secondary MR treated medically, survival tended to be lower in those with a higher RVol/EDV ratio. Conversely, a higher RVol/EDV ratio was independently associated with reduced all-cause mortality. when mitral valve interventions were taken into consideration     

Network Analysis of Cardiac Remodeling by Primary Mitral Regurgitation Emphasizes the Role of Diastolic Function

BackgroundTopological data analysis (TDA) can generate patient-patient similarity networks by analyzing large, complex data and derive new insights that may not be possible with standard statistics.ObjectivesThe purpose of this paper was to discover novel phenotypes of chronic primary mitral regurgitation (MR) patients and to analyze their clinical implications using network analysis of echocardiographic data.MethodsPatients with chronic moderate to severe primary MR were prospectively enrolled from 11 Asian tertiary hospitals (n = 850; mean age 56.9 ± 14.2 years, 57.9% men). We performed TDA to generate network models using 14 demographic and echocardiographic variables. The patients were grouped by phenotypes in the network, and the prognosis was compared by groups.ResultsThe network model by TDA revealed 3 distinct phenogroups. Group A was the youngest with fewer comorbidities but increased left ventricular (LV) end-systolic volume, representing compensatory LV dilation commonly seen in chronic primary MR. Group B was the oldest with high blood pressure and a predominant diastolic dysfunction but relatively preserved LV size, an unnoticed phenotype in chronic primary MR. Group C showed advanced LV remodeling with impaired systolic, diastolic function, and LV dilation, indicating advanced chronic primary MR. During follow-up (median 3.5 years), 60 patients received surgery for symptomatic MR or died of cardiovascular causes. Kaplan-Meier curves demonstrated that although group C had the worst clinical outcome (P < 0.001), group B, characterized by diastolic dysfunction, had an event-free survival comparable to group A despite preserved LV chamber size. The grouping information by the network model was an independent predictor for the composite of MR surgery or cardiovascular death (adjusted HR: 1.918; 95% CI: 1.257-2.927; P = 0.003).ConclusionsThe patient-patient similarity network by TDA visualized diverse remodeling patterns in chronic primary MR and revealed distinct phenotypes not emphasized currently. Importantly, diastolic dysfunction deserves equal attention when understanding the clinical presentation of chronic primary MR.     

Impact of Proportionality of Secondary Mitral Regurgitation on Outcome After Transcatheter Mitral Valve Repair

ObjectivesThe purpose of this paper was to evaluate the impact of proportionality of secondary mitral regurgitation (SMR) in a large real-world registry of transcatheter edge-to-edge mitral valve repair (TMVr)BackgroundDifferences in the outcomes of recent randomized trials of TMVr for SMR may be explained by the proportionality of SMR severity to left ventricular (LV) volume.MethodsThe ratio of pre-procedural effective regurgitant orifice area (EROA) to LV end-diastolic volume (LVEDV) was retrospectively assessed in patients undergoing TMVr for severe SMR between 2008 and 2019 from the EuroSMR registry. A recently proposed SMR proportionality scheme was adapted to stratify patients according to EROA/LVEDV ratio in 3 groups: MR-dominant (MD), MR-LV-co-dominant (MLCD), and LV-dominant (LD). All-cause mortality was assessed as a primary outcome, secondary heart failure (HF) outcomes included hospitalization for HF (HHF), New York Heart Association (NYHA) functional class, N-terminal pro–B-type natriuretic peptide (NT-proBNP), 6-min-walk distance, quality of life and MR grade.ResultsA total of 1,016 patients with an EROA/LVEDV ratio were followed for 22 months after TMVr. MR was reduced to grade ≤2+ in 92%, 96%, and 94% of patients (for MD, MLCD, and LD, respectively; p = 0.18). After adjustment for covariates including age, sex, diabetes, kidney function, body surface area, LV ejection fraction, and procedural MR reduction (grade ≤2+), adjusted rates of 2-year mortality in MD patients did not differ from those for MLCD patients (17% vs. 18%, respectively), whereas it was higher in LD patients (23%; p = 0.02 for comparison vs. MD+MLCD). The adjusted first HHF rate differed between groups (44% in MD, 56% in MLCD, 29% in LD; p = 0.01) as did the adjusted time for first death or HHF rate (66% in MD, 82% in MLCD, 68% in LD; p = 0.02). Improvement of NYHA functional class was seen in all groups (p < 0.001). Values for 6-min-walk distances, quality of life and NT-proBNP improved in most patients.ConclusionsMD and MLCD patients had a comparable, adjusted 2-year mortality rate after TMVr which was slightly better than that of LD patients. Patients treated with TMVr had symptomatic improvement regardless of EROA/LVEDV ratio.     

Prognostic Impact of Ischemic Mitral Regurgitation Severity and Myocardial Infarct Quantification by Cardiovascular Magnetic Resonance

ObjectivesThis study sought to evaluate the role of cardiac magnetic resonance (CMR) for the quantification of ischemic mitral regurgitation (IMR) and myocardial infarct size (MIS) in patients with ischemic cardiomyopathy (ICM). This study also sought to explore the interaction between IMR severity and MIS and its association with outcomes in patients with ICM.BackgroundIMR occurs secondary to a disease of the left ventricle and is associated with poor outcomes. The role of CMR for the evaluation and risk stratification of patients with ICM and IMR remains uncertain.MethodsConsecutive patients with ICM who underwent baseline CMR were included. MIS was quantified on late gadolinium enhancement imaging as the proportion of left ventricular mass. IMR was quantified with CMR by calculating the mitral regurgitant fraction (MRFraction). Cox proportional hazards models were built to assess the association of IMR and MIS quantification with the combined endpoint of all-cause death or heart transplant.ResultsWe evaluated 578 patients (mean age: 62 ± 11 years, 76% males). The mean left ventricular ejection fraction was 25 ± 11%, with an MIS of 24 ± 16% and MRFraction of 18 ± 17%. Over a median follow-up time of 4.9 years, 198 (34%) patients experienced death or cardiac transplant. On multivariable analysis, after comprehensive medical risk score, subsequent revascularization, implantable cardioverter-defibrillator insertion, and surgical mitral valve intervention were controlled for, the interaction of IMR severity and MIS emerged as a powerful predictor of adverse outcomes (p = 0.008). For patients with significant IMR (MRFraction: ≥35%), the hazard ratio comparing moderate MIS (15% to 29%) versus small MIS (<15%) was 1.51 (0.57 to 3.98), and the hazard ratio comparing large MIS (≥30%) versus small MIS was 5.41 (2.34 to 12.7).ConclusionsRisk associated with IMR is more comprehensively described as an interaction between IMR severity and MIS. Further studies in patients IMR using comprehensive CMR evaluation are needed to verify whether this approach can improve patient selection and procedural outcomes to address IMR.     

Prognostic Value of Left Ventricular Global Longitudinal Strain in Patients With Secondary Mitral Regurgitation

BackgroundLeft ventricular (LV) systolic function may be overestimated in patients with secondary mitral regurgitation (MR) when using LV ejection fraction (EF). LV global longitudinal strain (GLS) is a less load-dependent measure of LV function. However, the prognostic value of LV GLS in secondary MR has not been evaluated.ObjectivesThis study sought to demonstrate the prognostic value of LV GLS over LVEF in patients with secondary MR.MethodsA total of 650 patients (mean 66 ± 11 years of age, 68% men) with significant secondary MR were included. The study population was subdivided based on the LV GLS value at which the hazard ratio (HR) for all-cause mortality was >1 using a spline curve analysis (LV GLS <7.0%, impaired LV systolic function vs. LV GLS ≥7.0%, preserved LV systolic function). The primary endpoint was all-cause mortality.ResultsDuring a median follow-up of 56 (interquartile range: 28 to 106 months) months, 334 (51%) patients died. Patients with a more impaired LV GLS showed significantly higher mortality rates at 1-, 2-, and 5-year follow-up (13%, 23%, and 44%, respectively) when compared with patients with more preserved LV systolic function (5%, 14%, and 31%, respectively). On multivariable analysis, LV GLS <7.0% was associated with increased mortality (HR: 1.337; 95% confidence interval: 1.038 to 1.722; p = 0.024), whereas LVEF ≤30% was not (HR: 1.055; 95% confidence interval: 0.794 to 1.403; p = 0.711).ConclusionsIn patients with secondary MR, impaired LV GLS was independently associated with an increased risk for all-cause mortality, whereas LVEF was not. LV GLS may therefore be useful in the risk stratification of patients with secondary MR.     

Mitral Valve Remodeling and Strain in Secondary Mitral Regurgitation: Comparison With Primary Regurgitation and Normal Valves

ObjectivesThe aim of this study was to assess mitral valve (MV) remodeling and strain in patients with secondary mitral regurgitation (SMR) compared with primary MR (PMR) and normal valves.BackgroundA paucity of data exists on MV strain during the cardiac cycle in humans. Real-time 3-dimensional (3D) echocardiography allows for dynamic MV imaging, enabling computerized modeling of MV function in normal and disease states.MethodsThree-dimensional transesophageal echocardiography (TEE) was performed in a total of 106 subjects: 36 with SMR, 38 with PMR, and 32 with normal valves; MR severity was at least moderate in both MR groups. Valve geometric parameters were quantitated and patient-specific 3D MV models generated in systole using a dedicated software. Global and regional peak systolic MV strain was computed using a proprietary software.ResultsMV annular area was larger in both the SMR and PMR groups (12.7 ± 0.7 and 13.3 ± 0.7 cm², respectively) compared with normal subjects (9.9 ± 0.3 cm²; p < 0.05). The leaflets also had significant remodeling, with total MV leaflet area larger in both SMR (16.2 ± 0.9 cm²) and PMR (15.6 ± 0.8 cm²) versus normal subjects (11.6 ± 0.4 cm²). Leaflets in SMR were thicker than those in normal subjects but slightly less than those with PMR posteriorly. Posterior leaflet strain was significantly higher than anterior leaflet strain in all 3 groups. Despite MV remodeling, strain in SMR (8.8 ± 0.3%) was overall similar to normal subjects (8.5 ± 0.2%), and both were lower than in PMR (12 ± 0.4%; p < 0.0001). Valve thickness, severity of MR, and primary etiology of MR were correlates of strain, with leaflet thickness being the multivariable parameter significantly associated with MV strain. In patients with less severe MR, anterior leaflet strain in SMR was lower than normal, whereas strain in PMR remained higher than normal.ConclusionsThe MV in secondary MR remodels significantly and similarly to PMR with a resultant larger annular area, leaflet surface area, and leaflet thickness compared with that of normal subjects. Despite these changes, MV strain remains close to or in some instances lower than normal and is significantly lower than that of PMR. Strain determination has the potential to improve characterization of MV mechano-biologic properties in humans and to evaluate its prognostic impact in patients with MR, with or without valve interventions.     

Importance of Myocardial Fibrosis in Functional Mitral Regurgitation: From Outcomes to Decision-Making

Functional mitral regurgitation (FMR) is a common and complex valve disease, in which severity and risk stratification is still a conundrum. Although risk increases with FMR severity, it is modulated by subjacent left ventricular (LV) disease. The extent of LV remodeling and dysfunction is traditionally evaluated by echocardiography, but a growing body of evidence shows that myocardial fibrosis (MF) assessment by cardiac magnetic resonance (CMR) may complement risk stratification and inform treatment decisions. This review summarizes the current knowledge on the comprehensive evaluation that CMR can provide for patients with FMR, in particular for the assessment of MF and its potential impact in clinical decision-making.     

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

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

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

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

Resolving the Disproportionate Left Ventricular Enlargement in Mitral Valve Prolapse Due to Barlow Disease: Insights From Cardiovascular Magnetic Resonance

ObjectivesThis study hypothesized that left ventricular (LV) enlargement in Barlow disease can be explained by accounting for the total volume load that consists of transvalvular mitral regurgitation (MR) and the prolapse volume.BackgroundBarlow disease is characterized by long prolapsing mitral leaflets that can harbor a significant amount of blood—the prolapse volume—at end-systole. The LV in Barlow disease can be disproportionately enlarged relative to MR severity, leading to speculation of Barlow cardiomyopathy.MethodsCardiac magnetic resonance (CMR) was used to compare MR, prolapse volume, and heart chambers remodeling in patients with Barlow disease (bileaflet prolapse [BLP]) and in single leaflet prolapse (SLP).ResultsA total of 157 patients (81 with BLP, 76 with SLP) were included. Patients with SLP were older and more had hypertension. Patients with BLP had more heart failure. Indexed LV end-diastolic volume was larger in BLP despite similar transvalvular MR. However, the prolapse volume was larger in BLP, which led to larger total volume load compared with SLP. Increasing tertiles of prolapse volume and MR both led to an incremental increase in LV end-diastolic volume in BLP. Using the total volume load improved the correlation with indexed LV end-diastolic volume in the BLP group, which closely matched that of SLP. A multivariable model that incorporated the prolapse volume explained left heart chamber enlargement better than a MR-based model, independent of prolapse category.ConclusionsThe prolapse volume is part of the total volume load exerted on the LV during the cardiac cycle and could help explain the disproportionate LV enlargement relative to MR severity noted in Barlow disease.