Mitral Annular Dilatation Research Articles

Atrial and ventricular mitral regurgitation in the general population

Abstract Background Functional mitral valve regurgitation (FMR) is the result of two concurrent pathomechanisms: (1) the dilatation of mitral valve annulus (atrial) or (2) remodelling of the left ventricle (ventricular) in the absence of relevant leaflet degeneration¹. Even though FMR has been reported to be the most common cause of relevant MR², there is no general accepted definition of the two subtypes, nor are there population-based data regarding their prevalence, distribution and risk profiles¹. Purpose We aimed to evaluate the prevalence of FMR and to provide an in-depth characterisation of the subtypes aFMR and vFMR in the general population. Methods The study included the first 10,000 participants of the population-based Hamburg City Health Study enrolled between 2016 and 2019. Of these, 8.543 echocardiographic samples were available for analysis. Mitral valve was assessed by two independent investigators. Isolated degenerative MRs as determined by valve mobility (prolapse or restrictive) were excluded. FMR was classified as ventricular when fulfilling one of the following criteria: history of myocardial infarction or coronary artery disease, left ventricular ejection fraction (LVEF) ≤ 40%, restrictive leaflet, tenting area ≥ 150 mm² or coaptation depth ≥ 10 mm. All FMR with LVEF > 55% were classified as atrial. Results After excluding the samples with an insufficient image quality or missing data and re-assessment by the second investigator, 216 of 282 participants with a relevant MR (i.e. moderate or severe) remained (2,6% of the total cohort, see figure 1). In the next step, 153 participants were classified as pure FMR (68.9%), the remaining were mainly functional with minor degenerative features. A total of 31 (14.4%) MRs were classified as vFMR, the remaining 185 participants had an aFMR. Female gender was significantly more common in the aFMR cohort. The remaining demographic variables (age, body mass index) as well as established cardiovascular risk factors (i.e., diabetes, smoking, hypertension) were comparable between the vFMR and aFMR cohort. However, vFMR patients had significantly higher levels of NT-proBNP or NHYA state and presented more frequently with an atrial fibrillation (see figure 2). LVEF and LV stroke volume, TAPSE, left atrial ejection fraction and E/A ratio as a parameter of diastolic dysfunction were lower in the vFMR cohort whereas tenting area and left atrial endsystolic volume was significantly increased. Conclusion In our population-based study, aFMR was found to be the predominant subtype of FMR. The established cardiovascular risk factors were comparable in the vFMR and aFMR cohort. Echocardiographic variables differed significantly and indicate more advanced heart failure and LV remodelling in the vFMR cohort. Further categorization of FMR, in particular regarding the prognostic impact and long-term outcomes, is strongly warranted to allow a clinically relevant definition of aFMR and vFMR.Figure 1:Overview of sample sizeFigure 2:Baseline characteristics

Impact of Non-Valvular Atrial Fibrillation on Mitral Valve Anatomic Features: A Study of Three-Dimensional Mitral Valve by Transesophageal Echocardiography and Automatic Analysis Software.

Mitral regurgitation (MR) is frequently observed in non-valvular atrial fibrillation (NVAF) patients and is a significant risk factor for its progression. This study aims to investigate the three-dimensional anatomical characteristics of the mitral valve (MV) in patients with different types of NVAF to elucidate the underlying mechanisms of MR. A retrospective analysis was conducted on 82 paroxysmal atrial fibrillation patients (PAF group) and 66 persistent atrial fibrillation patients (PerAF group) who underwent real-time three-dimensional transesophageal echocardiography (RT 3D-TEE) before initial ablation. Additionally, 30 patients undergoing RT 3D-TEE for the assessment of patent foramen ovale were selected as the control group. Basic echocardiographic variables were measured, left atrioventricular volume and strain parameters were calculated using automated software (Dynamic-HeartModel and AutoStrain). MV anatomic features were analyzed using the 4D-MV Assessment software (TomTec Imaging Systems). The maximum left atrial volume (LAVmax) was highest in the PerAF group, followed by the PAF and control groups, with statistically significant differences (p<0.01). Left atrial reservoir strain (LASr) showed an opposite trend, being the lowest in the PerAF group (p<0.01). The proportion of moderate to severe MR was significantly higher in the PerAF group (27.3%) compared to the PAF group (11.0%) (p<0.01). Compared to controls, the AF groups exhibited mitral annular (MA) dilation, flattening of the MA plane, and increased leaflet area (all p<0.05). Correlation analysis between effective regurgitant orifice area (EROA) and left atrioventricular structure and function parameters, as well as various annular parameters, showed that EROA was significantly correlated with left ventricular end-diastolic volume (LVEDV), LAVmax, LASr, anterior and posterior diameter, annular area, ratio of annular height to commissural diameter (AH/CD ratio), posterior leaflet area, posterior leaflet length, and the C-shaped annulus length (all p<0.05). Significant remodeling of the MV apparatus occurs in NVAF patients, with more pronounced changes in PerAF patients, contributing to a higher incidence of moderate to severe MR. RT 3D-TEE-based MV automated assessment offers significant advantages in accurately diagnosing MV remodeling and supporting the evaluation of MR in NVAF patients.

Long-term Outcomes of Mitral Valve Repair for Atrial Functional Mitral Regurgitation

BackgroundAtrial functional mitral regurgitation (AFMR), defined by normal left ventricular function, enlarged left atrium, and a dilated mitral valve annulus, has been a concept discussed for >10 years. However, there are still no established guidelines for its treatment in the American College of Cardiology/American Heart Association recommendations. This study aimed to determine the long-term outcomes of mitral annuloplasty as a treatment for AFMR. MethodsWe analyzed 1435 patients who underwent mitral valve repair at our institution between 2005 and 2020, with 162 classified as having AFMR. Exclusion criteria for AFMR were established based on preoperative echocardiography and operative notes. The primary outcome was overall mortality, and the secondary outcome was MR recurrence, which was defined as moderate or greater mitral regurgitation observed on echocardiography during the follow-up period, analyzed using our hospital’s medical records and data from the National Statistical Office. ResultsThe median follow-up duration for the entire patient cohort was 6.1 years (interquartile range, 3.2-11.2 years). Patients had a 5-year survival rate of 86% and a 10-year survival rate of 73%, with freedom from MR recurrence rates of 89% and 80% at 5 and 10 years, respectively. Although all 162 patients had moderate or greater MR before surgery, most experienced trivial or mild MR after mitral valve repair throughout the follow-up period. ConclusionsIn summary, mitral valve repair effectively treats patients with AFMR, addressing survival and mitigating MR recurrence.

Atrial Functional Mitral Regurgitation Subtypes Undergoing Transcatheter Edge-to-Edge Repair: Suboptimal Outcomes in Atriogenic Hamstringing.

Two subtypes of atrial functional mitral regurgitation (AFMR) have been described, one is characterized by Carpentier type I and the other by Carpentier type IIIb leaflet motion. The authors sought to analyze echocardiographic characteristics and outcomes of AFMR subtypes undergoing mitral valve transcatheter edge-to-edge repair (M-TEER). Of 1,047 consecutive patients who underwent M-TEER, the authors identified those with isolated mitral annulus dilation (Carpentier I), termed AFMR-IAD, and those with atriogenic hamstringing characterized by restricted posterior mitral leaflet motion (Carpentier IIIb), termed AFMR-AH. Echocardiographic baseline characteristics and outcomes up to 1-year were analyzed. A total of 128 patients (12.2%) met AFMR criteria; 75 (58.6%) were identified as AFMR-IAD and 53 (41.4%) as AFMR-AH. AFMR-AH displayed greater left atrial and left ventricular volumes, greater mitral annulus, shorter and steeper posterior mitral leaflet, and more pronounced MR (all P< 0.05). Technical success was achieved in 98.7% (AFMR-IAD) and 86.8% (AFMR-AH) of patients (P = 0.009). At discharge, device detachments were exclusively observed in AFMR-AH (10.0%). MR≤II was achieved in 95.6% and 78.6% at 30days (P=0.009) and in 93.0% and 74.1% at 1 year (P = 0.038) in patients with AFMR-IAD and AFMR-AH, respectively. AFMR-AH was associated with procedural failure (OR: 1.17 [95%CI: 1.00-1.38]; P = 0.045) at 30days (43.4% vs 24.0%; P = 0.023) and all-cause mortality (HR: 2.54 [95%CI: 1.09-5.91]; P = 0.031) at 1 year (77% vs 92%, Kaplan-Meier estimated 1-year survival; P = 0.017). AFMR-AH shows worse procedural and clinical outcomes following M-TEER than AFMR-IAD. Thus, vigilance regarding this pathology is warranted and alternative mitral valve therapies might need to be considered.

Left Atrium: A New Prognostic Marker and Therapeutic Target in Secondary Mitral Regurgitation?

Mitral regurgitation (MR) is one of the most common valvular abnormalities worldwide and can be subdivided into primary and secondary causes. Atrial MR consists of a novel type of secondary MR (SMR), most often observed in patients with AF and heart failure with preserved ejection fraction. The main pathophysiological mechanism of atrial MR is mitral valve annular dilatation. Recently published studies have highlighted the clinical significance of left atrium (LA) evaluation in the early diagnosis and prognosis of patients with primary MR. However, there are little data regarding the role of the LA in SMR. The present literature review aims to elucidate the use of the echocardiographic parameters regarding LA evaluation in the prognosis prediction and therapeutic strategy of patients with SMR.

Acute mitral regurgitation complicating STEMI

Abstract Funding Acknowledgements None. Introduction Acute ischemic mitral regurgitation (aiMR) occurs in 17-40% of patients suffering an acute coronary syndrome. Although severe forms constitute less than 1% of the cases, this complication significantly increases mortality risk. While surgery has been traditionally considered the treatment of choice, heterogeneity in underlying mechanisms and lack of updated evidence questions optimal treatment. Purpose The aim of the present study was to describe baseline clinical characteristics, management and outcomes of a contemporary cohort of patients with aiMR. Methods A retrospective cohort including patients diagnosed with moderate to severe aiMR presenting from 2006 to 2019 at the National Institute of Cardiology "Ignacio Chavez" in Mexico City. Results A total of 10,434 patients presented to the study center with an ACS from 2006 to 2019, out of which 6,448 (61.8%) were diagnosed with STEMI and 3,986 (38.2%) with NSTEMI. Mechanical post-infarction complications occurred in 203 (1.9%). Among these, aiMR was observed in 132 patients (1.3%), categorized as moderate in 49 patients (37.2%) and severe in 83 patients (62.8%). 6 patients were excluded due to incomplete information. Acute ischemic mitral regurgitation was more frequent in patients with STEMI (79.4%) compared with NSTEMI (20.6%) and 88.9% were non-reperfused infarctions. 65.9% of patients were male and 57.1% had hypertension. In-hospital mortality was present in 40 patients (31.7%). Ischemia of the papillary muscle was the most commonly reported mechanism (38.1%), followed by alterations in the left ventricle's geometry (33.3%), mitral annular dilation (14.3%), papillary muscle rupture (7.1%) and chordae tendineae rupture (5.6%). The least frequently reported mechanism was pre existing non-ischemic mitral regurgitation (1.6%). There was no significant difference in mortality based on the mechanism responsible for aiMR. Patients with aiMR managed solely with medical therapy had a higher mortality rate (41.3%) compared to those undergoing mitral valve replacement (37%) (Figure 1). Timely reperfusion (thrombolysis/primary PCI) significantly reduced in-hospital mortality (85% survival) in contrast to those with a non-reperfused MI (66% survival). Conclusions Acute ischemic mitral regurgitation remains an entity with a high mortality rate. Early identification of underlying etiology, prompt reperfusion treatment and tailored surgery, if needed, are key to improve outcomes.

Simulated Effects of Acute Left Ventricular Myocardial Infarction on Mitral Regurgitation in an Ovine Model.

Ischemic mitral regurgitation (IMR) occurs from incomplete coaptation of the mitral valve (MV) after myocardial infarction (MI), typically worsened by continued remodeling of the left ventricular (LV). The importance of LV remodeling is clear as IMR is induced by the post-MI dual mechanisms of mitral annular dilation and leaflet tethering from papillary muscle (PM) distension via the MV chordae tendineae (MVCT). However, the detailed etiology of IMR remains poorly understood, in large part due to the complex interactions of the MV and the post-MI LV remodeling processes. Given the patient-specific anatomical complexities of the IMR disease processes, simulation-based approaches represent an ideal approach to improve our understanding of this deadly disease. However, development of patient-specific models of left ventricle-mitral valve (LV-MV) interactions in IMR are complicated by the substantial variability and complexity of the MR etiology itself, making it difficult to extract underlying mechanisms from clinical data alone. To address these shortcomings, we developed a detailed ovine LV-MV finite element (FE) model based on extant comprehensive ovine experimental data. First, an extant ovine LV FE model (Sci. Rep. 2021 Jun 29;11(1):13466) was extended to incorporate the MV using a high fidelity ovine in vivo derived MV leaflet geometry. As it is not currently possible to image the MVCT in vivo, a functionally equivalent MVCT network was developed to create the final LV-MV model. Interestingly, in pilot studies, the MV leaflet strains did not agree well with known in vivo MV leaflet strain fields. We then incorporated previously reported MV leaflet prestrains (J. Biomech. Eng. 2023 Nov 1;145(11):111002) in the simulations. The resulting LV-MV model produced excellent agreement with the known in vivo ovine MV leaflet strains and deformed shapes in the normal state. We then simulated the effects of regional acute infarctions of varying sizes and anatomical locations by shutting down the local myocardial contractility. The remaining healthy (noninfarcted) myocardium mechanical behaviors were maintained, but allowed to adjust their active contractile patterns to maintain the prescribed pressure-volume loop behaviors in the acute post-MI state. For all cases studied, the LV-MV simulation demonstrated excellent agreement with known LV and MV in vivo strains and MV regurgitation orifice areas. Infarct location was shown to play a critical role in resultant MV leaflet strain fields. Specifically, extensional deformations of the posterior leaflets occurred in the posterobasal and laterobasal infarcts, while compressive deformations of the anterior leaflet were observed in the anterobasal infarct. Moreover, the simulated posterobasal infarct induced the largest MV regurgitation orifice area, consistent with experimental observations. The present study is the first detailed LV-MV simulation that reveals the important role of MV leaflet prestrain and functionally equivalent MVCT for accurate predictions of LV-MV interactions. Importantly, the current study further underscored simulation-based methods in understanding MV function as an integral part of the LV.

Cardiac Mechanics and Valvular and Vascular Abnormalities in Hypereosinophilic Syndrome.

Hypereosinophilic syndrome (HES) is considered to be a rare myeloproliferative disease that is characterized by persistent eosinophilia with associated multiple-organ damage. The heart is often involved in HES, representing a major cause of morbidity and mortality. HES is a heterogeneous group of disorders; the majority of the cases are idiopathic. Summarizing the findings regarding myocardial, valvular, and vascular abnormalities in a series of patients with HES, most studies found normal left ventricular (LV) volumes with reduced LV global longitudinal strain and LV apical rotation and twist in HES cases, accompanied by increased left atrial (LA) volumes and stroke volumes, reduced peak LA circumferential strain (representing systolic abnormalities), and mitral annular dilation and functional deterioration. Regarding the right heart, preserved right ventricular volumes and functional properties, increased right atrial volumes, mild RA functional abnormalities, and dilated tricuspid annular dimensions without functional impairment could be seen in these studies. Aortic and pulmonary valves showed no specific disease-related alterations. Vascular abnormalities included increased aortic stiffness without dilation of the aorta and pulmonary hypertension in some cases. These results suggest disease-specific but relatively mild myocardial, valvular, and vascular abnormalities in HES. The present review aimed to summarize the available clinical data about cardiac mechanics and valvular and vascular abnormalities in a series of patients with HES.

Imaging for the assessment of the arrhythmogenic potential of mitral valve prolapse.

Mitral valve prolapse (MVP) is the most common valve disease in the western world and recently emerged as a possible substrate for sudden cardiac death (SCD). It is estimated an annual risk of sudden cardiac death of 0.2 to 1.9% mostly caused by complex ventricular arrhythmias (VA). Several mechanisms have been recognized as potentially responsible for arrhythmia onset in MVP, resulting from the combination of morpho-functional abnormality of the mitral valve, structural substrates (regional myocardial hypertrophy, fibrosis, Purkinje fibers activity, inflammation), and mechanical stretch. Echocardiography plays a central role in MVP diagnosis and assessment of severity of regurgitation. Several abnormalities detectable by echocardiography can be prognostic for the occurrence of VA, from morphological alteration including leaflet redundancy and thickness, mitral annular dilatation, and mitral annulus disjunction (MAD), to motion abnormalities detectable with "Pickelhaube" sign. Additionally, speckle-tracking echocardiography may identify MVP patients at higher risk for VA by detection of increased mechanical dispersion. On the other hand, cardiac magnetic resonance (CMR) has the capability to provide a comprehensive risk stratification combining the identification of morphological and motion alteration with the detection of myocardial replacement and interstitial fibrosis, making CMR an ideal method for arrhythmia risk stratification in patients with MVP. Finally, recent studies have suggested a potential role in risk stratification of new techniques such as hybrid PET-MR and late contrast enhancement CT. The purpose of this review is to provide an overview of the mitral valve prolapse syndrome with a focus on the role of imaging in arrhythmic risk stratification. CLINICAL RELEVANCE STATEMENT: Mitral valve prolapse is the most frequent valve condition potentially associated with arrhythmias. Imaging has a central role in the identification of anatomical, functional, mechanical, and structural alterations potentially associated with a higher risk of developing complex ventricular arrhythmia and sudden cardiac death. KEY POINTS: • Mitral valve prolapse is a common valve disease potentially associated with complex ventricular arrhythmia and sudden cardiac death. • The mechanism of arrhythmogenesis in mitral valve prolapse is complex and multifactorial, due to the interplay among multiple conditions including valve morphological alteration, mechanical stretch, myocardial structure remodeling with fibrosis, and inflammation. • Cardiac imaging, especially echocardiography and cardiac magnetic resonance, is crucial in the identification of several features associated with the potential risk of serious cardiac events. In particular, cardiac magnetic resonance has the advantage of being able to detect myocardial fibrosis which is currently the strongest prognosticator.

Moderate functional mitral regurgitation: difference between atrial and ventricular mechanism of the regurgitation

Abstract Background/Introduction In severe functional mitral regurgitation (MR), further distinction of the mechanism of MR in atrial functional MR (aFMR) and ventricular functional MR (vFMR) has shown prognostic importance. However, no data are available on moderate functional MR, whose characteristics and prognosis are largely unknown. Purpose To assess clinical and echocardiographic characteristics of patients with moderate aFMR and vFMR and their potential difference in outcome. Methods Patients with moderate functional MR were retrospectively included. aFMR was defined as isolated mitral annulus dilatation in combination with preserved left ventricular ejection fraction (LVEF≥50%) without ischemic heart disease or LV dilatation. Patients were classified as vFMR when LVEF was reduced, LV was dilated and/or wall motion abnormalities were present. Mitral valve intervention and all-cause mortality were used as combined endpoint. Results In total 474 patients with moderate functional MR (mean age 67 ±12, 57% male) were evaluated, of which 136 (29%) had aFMR and 338 (71%) had vFMR as underlying mechanism. Among the clinical variables, patients with aFMR had more atrial fibrillation (77% vs. 35%; p&amp;lt;0.001), were less symptomatic (NYHA class ≥ III: 6% vs. 18%; p&amp;lt;0.001) and had better renal function (eGFR 73 ±23 ml/min/1,73m2 vs. 65 ±23 ml/min/1,73m2; p=0.005) as compared to vFMR. In the vFMR group, 49% of patients had ischemic heart disease. Among the echocardiographic variables, as expected in aFMR, LVEF was higher (42 ±14% vs. 55 ±13%; p&amp;lt;0.001), while LV volumes (LV end-diastolic volume index 55 ±13 mL/m2 vs. 82 ±38 mL/m2; p&amp;lt;0.001) and E/E’ ratio were smaller (10 ±4 vs. 15 ±4; p&amp;lt;0.001) as compared to vFMR. However left atrial (LA) volume index was similar between both groups (43 ±14 mL/m2 vs. 41 ±18 mL/m2; p=0.271). For the echocardiographic measures of the right heart, significant difference was observed only for TAPSE which was higher for the aFMR group (22 ±4mm vs. 20 ±5mm; p&amp;lt;0.001). During a median follow-up of 74 months [IQR: 46.8-107.0], 132 (30%) patients died and 30 (6%) underwent mitral valve intervention. Event-free survival analysis for the combined endpoint was significantly better for aFMR patients (Figure 1). Based on significant variables from the univariable Cox regression analysis, multivariable Cox regression analysis showed that the mechanism of functional MR (with aFMR being protective as compared to vFMR), age, male gender, impaired renal function, NYHA class, severe LA dilatation and TAPSE were independently associated with the combined endpoint (Table 1). Conclusion In patients with moderate functional MR, aFMR is independently associated with better event-free survival as compared to vFMR. Therefore, clear identification of the mechanism of MR implies a better risk stratification and may be helpful for the management of patients with moderate MR.

Abstract 14699: Effects of Papillary Muscle Approximation and Annuloplasty Ring Sizing for Functional Mitral Regurgitation Repair in Enlarged Ventricles

Introduction: Our recent large animal study showed that papillary muscle approximation (PMA) repairs functional mitral regurgitation (FMR) and increases valve coaptation in enlarged left ventricles without negatively affecting ventricular function. However, since PMA does not reduce mitral annular dilation, addition of annuloplasty ring might be beneficial for such repair. In this study, we used computational modeling to investigate the benefit of the addition of annuloplasty to PMA and the effects of ring sizing on FMR repair in enlarged ventricles. Methods: 3D echo images were obtained in 3 pigs with heart failure, enlarged ventricles, and FMR. Each echo dataset was segmented, and computational model of the mitral valve was developed. To mimic PMA repair, the papillary muscles were drawn together in diastole. A true-sized annuloplasty ring of 40 mm and two downsized-rings of 38 mm and 36 mm were then added to each model. Leaflet closure was simulated and mitral valve geometry and biomechanics in peak systole were evaluated ( Fig A-B ). Results: On average, compared to pre-repair, PMA increased coaptation area by 30.6%, while the addition of annuloplasty increased this area by 85.1% with 40 mm, 138.1% with 38 mm, and 190.6% with 36 mm ring. Tenting area was reduced by 45.8% after PMA, 64.1% with the addition of 40 mm ring, 70.6% with 38 mm, and 76.5% with 36 mm ring. PMA reduced tension forces in chordae by 19.8%, while adding true-sized ring reduced forces by 16.4%. Annular downsizing allowed to reduce chordal forces by 31.2% with 38 mm, and 43.0% with 36 mm ring. Peak leaflet stress was observed on the P2 cusp, and PMA reduced it by 26.9%. True-sized ring reduced peak stress by only 10.7%, while 38 mm ring by 29.9%, and 36 mm by 43.7% ( Fig C ). Conclusions: Addition of true-sized ring to PMA further improved systolic valve geometry but not biomechanical parameters. Annular downsizing added to PMA was more beneficial for FMR repair, as it improved both mitral valve geometry and biomechanics.

Determinants of disproportionate functional mitral regurgitation

Abstract Funding Acknowledgements Type of funding sources: None. Background Recent studies have suggested that "disproportionate" functional mitral regurgitation (FMR) defined by greater MR than expected from the degree of left ventricular (LV) dilatation may be a good candidate for transcatheter edge-to-edge repair (TEER). Determinants of disproportionate FMR (d-FMR) is unknown. We hypothesized that additional factors such as asymmetric tethering, extreme mitral annular dilatation, and deep indentation, might worsen the severity of FMR regardless of LV volumes and lead to d-FMR. Purpose To investigate the impact of the additional factors on the proportionality of FMR. Methods We reviewed consecutive FMR patients who underwent TEER and 3D transesophageal echocardiography (3DTEE) in our institute between 2018 and 2022. d-FMR and proportionate FMR (p-FMR) were defined by the effective regurgitant orifice area (EROA)/LV end-diastolic volume (LVEDV) &amp;gt;0.2 and ≤0.2 mm2/mL, respectively. Results A total of 110 FMR patients (63 d-FMR and 47 p-FMR, 75±12 years old, 46.3% female) were included. Patients with d-FMR had significantly larger EROA than p-FMR (41 ± 12 vs 33 ± 11 mm2, P&amp;lt;0.001) despite smaller LVEDV index (100 ± 28 vs 138 ± 49 mL/m2, P&amp;lt;0.001), better LV ejection fraction (37 ± 10% vs 27 ± 8%, P&amp;lt;0.001), and lower tenting height (7.6 ±2.9 vs 9.4 ± 2.7 mm, P=0.009). The 3DTEE analysis revealed that patients with d-FMR were more likely to have asymmetric tethering (29% vs 21%), extreme mitral annular dilatation (&amp;gt;700 mm2/m2; 54% vs 30%), and deep indentation (22% vs 4.3%) The presence of such additional factors was independently associated with d-FMR (odds ratio 3.83, P=0.0081) after adjustment by body surface area and LVEDV index. Furthermore, EROA/LVEDV increased as the number of additional factors increased. (Jonckheere-Terpstra test, P&amp;lt;0.001). TEER successfully reduced FMR regardless of the presence of such additional factor (success rate 95% vs. 96%, P&amp;gt;0.99). Conclusions The presence of additional factors exacerbates MR independently of LV size and is an important mechanism of d-FMR. TEER is an effective therapy to reduce FMR regardless of these factors.

Impact of bench repair for donor mitral valve before orthotopic heart transplantation: a case report

BackgroundThe use of donor hearts with valvular disease has been considered debatable in heart transplantation for many years. However, few reports indicate successful heart transplantation using donor hearts with mitral regurgitation that underwent mitral valve repair on the back bench.Case presentationWe report two cases of a 38-year-old and a 48-year-old woman with implantable left ventricular assist devices who underwent heart transplantation at our institution. Transthoracic echocardiography of donor hearts just before the explant revealed that each donor heart had preserved cardiac function and significant mitral regurgitation due to mitral posterior leaflet prolapse and annular dilatation, respectively. Bench mitral valve repair was accomplished using triangular resection for one patient and annuloplasty for the other. This was followed by confirmation of excellent mitral leaflet coaptation without residual mitral regurgitation. Transthoracic echocardiography and right heart catheterization performed 6 months after transplantation clarified the favorable cardiac function of each transplanted heart without mitral regurgitation recurrence.ConclusionsEfficient utilization of donor hearts with mitral regurgitation may be acceptable when the cardiac function of donor hearts with mitral regurgitation is preserved and heart transplantation, including bench mitral valve repair, is feasible within an acceptable ischemic time.

Atrial functional mitral regurgitation: prevalence, characteristics and outcomes from the National Echo Database of Australia

AimsAtrial functional mitral regurgitation (AFMR) is characterised by left atrial and consequent mitral annular dilatation causing mitral regurgitation. AFMR is likely to become more common with population ageing, alongside increases...

Mitral Valve Coaptation Reserve Index: A Model to Localize Individual Resistance to Mitral Regurgitation Caused by Annular Dilation

The objective of this study was to develop a mathematical model for mitral annular dilatation simulation and determine its effects on the individualized mitral valve (MV) coaptation reserve index (CRI). A retrospective analysis of intraoperative transesophageal 3-dimensionalechocardiographic MV datasets was performed. A mathematical model was created to assess the mitral CRI for each leaflet segment (A1-P1, A2-P2, A3-P3). Mitral CRI was defined as the ratio between the coaptation reserve (measured coaptation length along the closure line) and an individualized correction factor. Indexing was chosen to correct for MV sphericity and area of largest valve opening. Mathematical models were created to simulate progressive mitral annular dilatation and to predict the effect on the individual mitral CRI. At a single-center academic hospital. Twenty-five patients with normally functioning MVs undergoing cardiac surgery. None. Direct measurement of leaflet coaptation along the closure line showed the lowest amount of coaptation (reserve) near the commissures (A1-P1 0.21 ± 0.05 cm and A3-P3 0.22 ± 0.06 cm), and the highest amount of coaptation (reserve) at region A2 to P2 0.25 ± 0.06 cm. After indexing, the A2-to-P2 region was the area with the lowest CRI in the majority of patients, and also the area with the least resistance to mitral regurgitation (MR) occurrence after simulation of progressive annular dilation. Quantification and indexing of mitral coaptation reserve along the closure line are feasible. Indexing and mathematical simulation of progressive annular dilatation consistently showed that indexed coaptation reserve was lowest in the A2-to-P2 region. These results may explain why this area is prone to lose coaptation and is often affected in MR.

Abstract 10259: A Case of Mitral Annulus Disjunction Highlighting a Disjunction in Our Knowledge

A 56-year-old female patient was brought to our hospital after she suffered a witnessed cardiac arrest while flying on an airplane. She underwent bystander (in the aisle) CPR for about 20 minutes while forcing the plane to land. Altogether, she received seven shocks via AED. At the time of our evaluation, she was alert and in no distress. She did not carry a family history of SCD but reported “she had an issue with heart valve”. Her initial ECG showed atrial fibrillation with a heart rate of 135 bpm, QTc of 515 ms and no findings suggestive of myocardial injury. Her initial workup showed a potassium level of 3.2 mmol/L and no other significant laboratory abnormalities. Her TTE revealed thickened mitral valve leaflets with bileaflet prolapse and severe (4+) central MR. In addition, mitral annular disjunction (MAD) was noted. Her LVEF was 65% with normal wall motion. A left heart catheterization demonstrated normal coronary arteries. Following, a cardiac MRI confirmed MAD at the P3 scallop only, dilated mitral annulus and with a disjunction gap of 7 mm. Furthermore, there was no intramyocardial or annular late gadolinium enhancement (LGE) noted. An ICD was implanted for secondary prevention and she was then referred for mitral valve repair. With this case, we aim at increasing awareness of MAD and SCD. Currently, clinicians rely mostly on anecdotal evidence. While there is increasing literature suggesting the arrhythmogenic nature of MAD, the pathophysiology and implications are still debated. Interestingly, a subject of recent debate, our patient did not have any LGE suggesting no scar/fibrosis that would serve as a nidus for ventricular arrhythmias. Further, a threshold disjunction gap distance of clinical significance has yet to be determined. The benefit of surgical correction remains unclear. Indeed, further prospective studies are required to delineate MAD and help guide early management and its’ ultimate impact on prognosis

The mitral annulus in transposition of the great arteries late after Senning- and Mustard-procedures (Insights from the CSONGRAD Registry and MAGYAR-Path Study).

Dextro-transposition of the great arteries (dTGA) is a rare condition comprising 5-7% of all congenital heart diseases (CHD). Until 1990s, atrial switch operations were the method of choice for the treatment of dTGA. The aim of our present study was to evaluate the abnormalities of the mitral annulus (MA) by three-dimensional speckle-tracking echocardiography (3DSTE). Potential differences in MA dimensions and functional properties late after Senning- and Mustard-procedures were analyzed as well. This retrospective cohort study comprised 19 dTGA patients late after atrial switch operation, from which 7 subjects were not involved due to inferior image quality. The remaining dTGA patient group comprised 12 subjects (age: 30.7±8.6 years, 7 males). For comparisons, 32 age- and gender-matched healthy controls were evaluated (age: 34.4±12.3 years, 18 males). End-systolic and end-diastolic MA diameter (MAD), area and perimeter proved to be increased, while MA functional parameters [MA fractional area change (MAFAC) and fractional shortening (MAFS)] were reduced in all dTGA patients as compared to matched controls regardless of the atrial switch procedure used. However, MA morphological parameters were tendentiously lower, while MA functional parameters were tendentiously favorable in case of Senning-procedure compared to Mustard-procedure. dTGA is accompanied by MA dilation and its functional impairment late after Senning- and Mustard-procedures.

C14 A PROMISING SURGICAL TECHNIQUE IN PATIENTS WITH ATRIAL FUNCTIONAL MITRAL REGURGITATION: HYPER–DOWN–SIZING ANNULOPLASTY

Abstract Objective Atrial functional mitral valve regurgitation is a less common form of functional mitral regurgitation with normal leaflet motion and morphology, preserved dimension and function of left ventricle, associated with atrial fibrillation ad/or left atrial dilatation. Several factors are involved into the etiology, such as mitral annular dilation and insufficient leaflet remodeling, atriogenic leaflet tethering, loss of annular saddle shape and contractility, changes in heart rate. Methods Eleven consecutive patients with atrial functional mitral regurgitation, mean age 65 ± 12 years, normal left ventricle dimension and ejection fraction greater than 50% underwent mitral valve repair via right mini–thoracotomy in case of isolated mitral and tricuspid valve surgery or via median sternotomy in case of combined procedures. Concomitant procedures include tricuspid valve repair in 1 patient and coronary artery bypass in 5 patients. All patients presented an increased dimension of left atrium (mean left atrial volume: 90 ± 23 ml); mitral annular dimension was investigated with trans–esophageal echocardiography before operation. In all patients was implanted a downsized complete rigid annuloplasty ring with asymmetrical design of two sizes smaller respect to measured intercommissural distance. Clinical outcomes of patients and echocardiographic findings related to mitral regurgitation recurrence and left ventricle function were followed in the time. Results At discharge, any patient present a residual mitral regurgitation greater than mild, mean trans–mitral gradient was 2.5 ±2.1 mmHg. During the follow–up period of 24 ± 5 months, the New York Heart Association functional class significantly improved from 2.5 ± 0.4 to 1.5 ± 2.1. In three patients occurred cardiac rhythm disturbances requiring hospital stay, only one patient developed a greater than mild mitral regurgitation, reoperation was not becessary in any case. Left atrial volume decreased from 90 ± 23 ml to 58 ± 30 ml. Conclusions Mitral annuloplasty with downsized ring is a safe and effective procedure in patient with atrial functional mitral regurgitation in the same way of patient with functional mitral regurgitation due to ventricular dilation and tethering. The comforting clinical and echocardiographic outcome in our small group of patient encourage future studies in this particular group of patients.

Ex vivo biomechanical analysis of flexible versus rigid annuloplasty rings in mitral valves using a novel annular dilation system

BackgroundMitral annuloplasty rings restore annular dimensions to increase leaflet coaptation, serving a fundamental component in mitral valve repair. However, biomechanical evaluations of annuloplasty rings are lacking. We aim to biomechanically analyze flexible and rigid annuloplasty rings using an ex vivo mitral annular dilation model.MethodsJuvenile porcine mitral valves (n = 4) with intercommissural distance of 28 mm were dilated to intercommissural distances of 40 mm using a 3D-printed dilator and were sewn to an elastic mount. Fiber bragg grating sensors were anchored to native chordae to measure chordal forces. The valves were repaired using size 28 rigid and flexible annuloplasty rings in a random order. Hemodynamic data, echocardiography, and chordal force measurements were collected.ResultsMitral annular dilation resulted in decreased leaflet coaptation height and increased mitral regurgitation fraction. Both the flexible and rigid annuloplasty rings effectively increased leaflet coaptation height compared to that post dilation. Rigid ring annuloplasty repair significantly decreased the mitral regurgitation fraction. Flexible annuloplasty ring repair reduced the chordal rate of change of force (7.1 ± 4.4 N/s versus 8.6 ± 5.9 N/s, p = 0.02) and peak force (0.6 ± 0.5 N versus 0.7 ± 0.6 N, p = 0.01) compared to that from post dilation. Rigid annuloplasty ring repair was associated with higher chordal rate of change of force (9.8 ± 5.8 N/s, p = 0.0001) and peak force (0.7 ± 0.5 N, p = 0.01) compared to that after flexible ring annuloplasty repair.ConclusionsBoth rigid and flexible annuloplasty rings are effective in increasing mitral leaflet coaptation height. Although the rigid annuloplasty ring was associated with slightly higher chordal stress compared to that of the flexible annuloplasty ring, it was more effective in mitral regurgitation reduction. This study may help direct the design of an optimal annuloplasty ring to further improve patient outcomes.

Mitral valve prolapse, mitral annular disjunction, left ventricular basal hypertrophy and ventricular repolarization abnormalities in Marfan patients

Mitral valve prolapse (MVP) has been associated with ventricular arrhythmia, originating from inferolateral left ventricle (LV) wall. However, its mechanism remains unclear. To take advantage of the high prevalence of MVP in Marfan syndrome (MFS) to study the relationship of MVP, mitral annular disjunction (MAD), LV basal hypertrophy and ECG abnormalities. We included all MFS patients (≥ 14 yo) without a history of thoracic surgery seen in our center between 2015 and 2017. MVP was identified on echocardiography according to Levine definition and the other cases of abnormal systolic mitral leaflet displacement were defined as billowing. Basal inferolateral hypertrophy (BILH) was defined as basal inferolateral thickness ≥ 12 mm and basal to mild wall thickness ratio ≥ 1.5. QTc was measured on rest 12-lead ECG ( Fig. 1 ). Two hundred and fifty MFS patients were included. Billowing or MVP (BMVP) was present in 187 (74.80%) patients. MAD was present in 52/235 (22.13%) and was associated with BMVP in all cases. End-systole mitral annular diameter was larger when BMVP was present (mean: 34.82 mm vs. 30.53 mm, P < 0.0001) and in MAD+ than in MAD− (mean: 37.14 mm vs. 32.46 mm, P < 0.0001) with a correlation between MAD length and end-systole mitral annular diameter (r = 0.395 P < 0.0001). Whereas mitral annular diameter decreased in systole in MAD−, it increased in MAD+ (mean mitral annular diameter (diastolic–systolic): 3.69 mm vs. −0.87 mm, P < 0.0001). BILH was present in 18/175 (10.29%) patients with BMVP vs. in 1/59 (1.69%) without ( P = 0.0367) and in 9/50 (18%) MAD+ vs. 10/174 (5.75%) MAD− ( P = 0.006). No electric abnormality on ECGs was associated with MAD or BMVP. In contrast, patients with BILH had a longer QTc than patients without HBIL (mean: 426ms vs. 411.4ms, P = 0.0220). In MFS population, MAD is associated with BMVP, systolic mitral annular dilatation, and BILH but not with ECG abnormalities. Only patients with BILH present a QTc prolongation.