Anatomical Similarities Between Mitral and Tricuspid Valves in Sheep, Ovis aries, Hearts

With the recent rapid growth in transcatheter mitral and tricuspid valve interventions, it has become increasingly important to understand detailed anatomy of the valves. In this study, we investigated the similarities, differences, and associations between the dimensions of the atrioventricular valves in a sheep model, as sheep heart valves have a similar morphology to human valves. A systematic dissection of twenty-five sheep hearts was performed, with annular circumference measurement, and sub-valvular anatomy documentation. There was a significant association (r=0.865; p=0.007) between the circumference of the mitral and tricuspid annuli. Authors also identified significantly more chordae tendinea in the subvalvular mitral apparatus compared to the tricuspid valve (15.8±1.2 vs. 13.9±1.5; p<0.001). In conclusion, there is a significant association between the size of mitral and tricuspid valve annuli, and the morphology of leaflets and subvalvular apparatus is different between the two valves. These findings could have important implications in transcatheter device design, sizing, and optimal intervention timing.

Cardiovascular Calcification as a Marker of Increased Cardiovascular Risk and a Surrogate for Subclinical Atherosclerosis: Role of Echocardiography

The risk prediction of future cardiovascular events is mainly based on conventional risk factor assessment by validated algorithms, such as the Framingham Risk Score, the Pooled Cohort Equations and the European SCORE Risk Charts. The identification of subclinical atherosclerosis has emerged as a promising tool to refine the individual cardiovascular risk identified by these models, to prognostic stratify asymptomatic individuals and to implement preventive strategies. Several imaging modalities have been proposed for the identification of subclinical organ damage, the main ones being coronary artery calcification scanning by cardiac computed tomography and the two-dimensional ultrasound evaluation of carotid arteries. In this context, echocardiography offers an assessment of cardiac calcifications at different sites, such as the mitral apparatus (including annulus, leaflets and papillary muscles), aortic valve and ascending aorta, findings that are associated with the clinical manifestation of atherosclerotic disease and are predictive of future cardiovascular events. The aim of this paper is to summarize the available evidence on clinical implications of cardiac calcification, review studies that propose semiquantitative ultrasound assessments of cardiac calcifications and evaluate the potential of ultrasound calcium scores for risk stratification and prevention of clinical events.

Diagnostic value of echocardiographic indices of left atrial and ventricular morphology in dogs with myxomatous mitral valve disease (MMVD)

Myxomatous mitral valve disease (MMVD) is one of the most common acquired diseases of the cardiovascular system of genetic etiology in small breed dogs. A long asymptomatic course characterizes the disease. Presently, the main diagnostic technique for heart diseases is echocardiography. This study evaluates individual echocardiographic indices of the left atrial and ventricular morphology with the determination of the diagnostic value of each of them in predicting the course of the disease. The study was conducted in a private veterinary hospital “Eurovet” and on the basis of the clinic of the Department of internal animal diseases and clinical diagnostics of Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnology Lviv during 2018–2019. The objects consisted of 46 dogs with a confirmed diagnosis of myxomatous mitral valve disease according to the recommendations of the American College of Veterinary Internal Medicine (ACVIM) and no signs of comorbidities. During the study, three experimental groups of animals were formed according to the clinical and functional status characteristic of each stage of MMVD development – B1, B2, C. According to the results, all experimental dogs showed changes in the mitral apparatus in the form of thickening of the anterior and posterior cusps, mitral valve (MV) prolapse into the left atrial (LA) cavity and regurgitation (MR), the severity of which increased with the stage of the disease (from 20 % to 60 %). In 44.4 % of animals in group B2, thickening of the left ventricular walls was diagnosed in diastole and in 22.2 % in systole. Instead, these values increase to 46.1 % and 53.8 % in group C, respectively. However, the degree of hypertrophy is disproportionate. With the development of the disease, we detect its decrease from 0.64 ± 0.03 (group B1) to 0.50 ± 0.04 (group B2) and 0.51 ± 0.03 (group C) also we observed an increase in LVEDD/2 from 1.30 ± 0.05 cm (group B1) to 1.46 ± 0.12 cm (group B2) and 1.54 ± 0.13 cm (group C). The value of nLVEDD in B1 was 1.36 times (P < 0.001) lower compared to B2 and C. Higher values of this parameter were found in 23.1 % of dogs in group C compared to the maximum value of B2. As MV insufficiency progresses, the LA/Ao index increases slightly (1.08 times) in B2, followed by an increase in C (1.38 times, P < 0.001). At the same time, we diagnose an increase (P < 0.05) in PV/PA by 1.18 times in B2 and 1.46 times (P < 0.001) in C. Thus, an increase in the severity of mitral regurgitation, a rapid increase in nLVEDD, the dynamics of the decrease in the degree of hypertrophy h/R, as well as an increase in LA/AO, PV/PA indices are predictors of unfavorable prognosis of myxomatous degeneration of the mitral valve in dogs.

Abstract 12806: Anatomic Correlates of Systolic Anterior Motion in D-looped Transposition of the Great Arteries Post Atrial Switch

Introduction: A paucity of data exists of the anatomic-physiological mechanisms for sub-pulmonic systolic anterior motion (SAM) of the mitral valve (MV) in d-looped transposition of the great arteries post atrial switch (d-TGA/AtS). Hypothesis: The development of SAM may be inherent to the anatomy of the MV or affected by external factors such as a dilated systemic right ventricle (RV) or pectus deformity. Methods: Clinical and cardio-imaging analysis of 18 adult patients with d-TGA/AtS (Age 42±6 years old, 56% Male) between 2015-2019 was performed. Echocardiography data included mitral apparatus anatomy (Figure) and CT/MRI data included biventricular dimensions, function, and Haller index (HI). Results: Patients with leaflet SAM (n=5) compared to patients without SAM (n=13) had significantly higher MV protrusion height (2.1 ± 0.4 vs 1.5 ± 0.4 cm p ≤0.01, respectively, Table) and longer anterior MV leaflet length (3.0 ± 0.24 vs 2.6 ± 0.34 cm p ≤0.05, respectively, Table) when compared to those without. CT/MRI showed higher sub-pulmonic left ventricular ejection fraction (LVEF) in the SAM group relative to No SAM (68 ± 5 vs 54 ± 7 % p ≤0.005, respectively, Table). RV size and function, chest deformity (HI>3.5), presence of a ventricular lead pacemaker, and septal thickness did not play a role in development of SAM (Table). Conclusions: An elongated mitral apparatus is associated with the development of SAM in d-TGA/AtS and the development of LVOT obstruction. Increased sub-pulmonic LVEF contributes to SAM, whereas the systemic RV dimensions, septal thickness, and degree of chest deformity do not correlate with SAM.

Double outlet right ventricle, pulmonary stenosis and congenital mitral stenosis

A 4-year-old girl child was diagnosed with double outlet right ventricle (DORV), severe pulmonary stenosis, and supramitral ring. This case is presented to bring to light this rare association. Through this report, we aim to stress importance of assessing mitral apparatus on echocardiography during evaluation for situations like DORV and Tetralogy of Fallot (TOF). The physiological differences in such situations as opposed to their isolated counterparts and special postoperative outcomes are also discussed.

P762 Preserved mitral apparatus dynamics predict the improvement of acute ischemic mitral regurgitation: four-dimensional quantitative echocardiographic study

Background We sought to evaluate the predictive value of acute stage mitral apparatus geometry and dynamics for the reduction of ischemic mitral regurgitation (IMR) in the remote phase after successful primary percutaneous coronary intervention (pPCI) by using real-time 3D-transthoracic echocardiography (3D-TTE). Methods We performed 2D and 3D-TTE in consecutive 44 first acute MI patients with more than mild IMR within 3 days after successful pPCI. 3DTTE of left ventricle (LV) volumes and mitral apparatus dynamics through the cardiac cycle were quantified offline. We compared the 3D geometric and dynamic parameters in the acute phase between 1)20 remained MR group and 2)24 improved MR group in 6-to-12 months after MI onset. Results Ejection fraction (EF) was preserved in the improved MR group compared to the remained MR group (49.0 ± 11.2 vs. 56.5 ± 7.0%, p = 0.013). Mitral valve annulus area, leaflet tenting length and papillary muscles spatial position had no significant difference between the two groups (all p &gt; 0.05) throughout cardiac cycle. In contrast, mitral annulus saddle shape was preserved in the improved MR group than the remained MR group (p = 0.010) and annular area changed dynamically through early- to late-systole in the improved MR group (phasic p = 0.017) despite it was adynamic in remained MR group (phasic p = 0.201). Conclusions: IMR improvement in the remote phase after AMI associated with preserved EF, mitral annulus saddle shape and dynamics during systole in the acute phase of MI. 4D dynamics of the mitral apparatus can be clinically useful predictor of the improvement in acute IMR and may contribute to the clinical decision making including surgical or percutaneous intervention for IMR.

P752 Mitral regurgitation in patients with severe aortic stenosis: role of valvular calcification in the persistence of mitral regurgitation after aortic valve replacement

Introduction mitral regurgitation is often associated with severe aortic stenosis but the indications for its correction at the time of aortic valve surgery are still unclear. Despite the indication for mitral valve repair or replacement in the case of severe secondary mitral regurgitation, many patients are left untreated. This is due to the common belief that secondary mitral regurgitation mostly improves after the aortic valve is treated. Purpose the aim of the study is to investigate the prevalence and distribution of mitral calcifications, their role in the development of mitral regurgitation and in its reduction after aortic valve replacement. Methods we reviewed all patient’s records who underwent aortic valve replacement for aortic stenosis at our institution from 12/2014 to 12/2016. Pre and post-operative echocardiograms were reviewed by experienced echocardiographer. Patients were then divided into 4 categories (functional, mild, moderate and severe calcification) on the basis of the presence, distribuition and severity of calcification on the mitral apparatus. Results at the end 651 patients were collected and analyzed. Mean age was 74yo. 334 (51,4%) of them were males. Most patients (63,1%) had only mild mitral regurgitation but 147 (22,6%) of them had moderate or severe mitral regurgitation. The presences of moderate or severe calcification of the mitral apparatus resulted to be a risk factor for the presence of mitral regurgitation associated with aortic stenosis as shown in Table 1. After surgical aortic valve replacement less than 21% of the patients showed a reduction of the degree of mitral regurgitation. We found no statistical difference between groups about mitral regurgitation changes after aortic valve replacement. Conclusions Mitral regurgitation is a common finding in patients with severe aortic stenosis and it’s prevalence is higher in patients with mitral calcifications. Few patients, however showed a reduction in the degree of mitral regurgitation after surgical aortic valve replacement with no difference related to the severity of annular or leaflets calcifications. TABLE 1 Logistic regression for the presence of mitral regurgitation Mitral Regurgitation Change after Aortic Valve Replacement CALCIFICATION DEGREE OR C.I. 95% p Reduced p Unchanged p Increased p Functional 53(21%) 176(71%) 18(7%) Mild 1.244571 0.81 - 1.93 0.32 28(20%) 0.86 105(76%) 0.43 6(4%) 0.34 Moderate 1.637297 1.05 - 2.56 0.03* 25(17%) 0.41 109(76%) 0.34 9(6%) 0.86 Severe 2.369245 1.46 - 3.85 &lt;0.01* 29(25%) 0.48 78(68%) 0.67 7(6%) 0.86 OR= Odds Ratio; C.I.=Confidence Interval; Functional= no calcification; Mild, Moderate and Severe= degree of mitral annular and leaflets calcifications.