Statistical assessment of normal mitral annular geometry using automated three-dimensional echocardiographic analysis.

BACKGROUND: The basis of mitral annuloplasty ring design has progressed from qualitative surgical intuition to experimental and theoretical analysis of annular geometry with quantitative imaging techniques. In this work, we present an automated three-dimensional (3D) echocardiographic image analysis method that can be used to statistically assess variability in normal mitral annular geometry to support advancement in annuloplasty ring design. METHODS: Three-dimensional patient-specific models of the mitral annulus were automatically generated from 3D echocardiographic images acquired from subjects with normal mitral valve structure and function. Geometric annular measurements including annular circumference, annular height, septolateral diameter, intercommissural width, and the annular height to intercommissural width ratio were automatically calculated. A mean 3D annular contour was computed, and principal component analysis was used to evaluate variability in normal annular shape. RESULTS: The following mean ± standard deviations were obtained from 3D echocardiographic image analysis: annular circumference, 107.0 ± 14.6 mm; annular height, 7.6 ± 2.8 mm; septolateral diameter, 28.5 ± 3.7 mm; intercommissural width, 33.0 ± 5.3 mm; and annular height to intercommissural width ratio, 22.7% ± 6.9%. Principal component analysis indicated that shape variability was primarily related to overall annular size, with more subtle variation in the skewness and height of the anterior annular peak, independent of annular diameter. CONCLUSIONS: Patient-specific 3D echocardiographic-based modeling of the human mitral valve enables statistical analysis of physiologically normal mitral annular geometry. The tool can potentially lead to the development of a new generation of annuloplasty rings that restore the diseased mitral valve annulus back to a truly normal geometry.

Echocardiographic assessment of mitral regurgitation: general considerations.

Echocardiography is undoubtedly one of the main tools used in assessment of mitral regurgitation (MR) because it allows characterization of valvular morphology, assessment of the severity of the regurgitation, and its secondary effects. In this article we present an overview of the echocardiographic assessment of MR.

Three-dimensional dynamic assessment of tricuspid and mitral annuli using cardiovascular magnetic resonance.

AIMS: To explore the potentiality of cardiovascular magnetic resonance (CMR) in the quantitative evaluation of mitral valve annulus (MVA) and tricuspid valve annulus (TVA) morphology and dynamics. METHODS AND RESULTS: CMR was performed in 13 normal subjects and 9 patients with mitral (n = 7) or tricuspid regurgitation (n = 2), acquiring cine-images in 18 radial long-axis planes passing through the middle of MVA or TVA. A novel algorithm was used to obtain dynamic three-dimensional (3D) reconstruction of MVA and TVA. Analysis was feasible in all cases, allowing accurate 3D annular reconstruction and tracking. The 3D area increased from systole [MVA, median = 10.0 cm(2) (first quartile = 8.6, third quartile = 11.4); TVA, 11.2 cm(2) (8.8-13.2)] to diastole [MVA, 10.6 cm(2) (9.4, 11.7); TVA, 11.9 cm(2) (9.2-13.5)], with TVA larger than MVA. While the longest diameter showed similar systolic and diastolic values, the shortest diameter elongated from systole [MVA, 30 mm (29-33); TVA, 33 mm (31-36)] to diastole [MVA, 31 mm (29-32); TVA, 36 mm (33-39)]. Also, TVA became more circular than MVA. TVA showed lower peak systolic excursion in the septal [15.9 mm (13.0-18.5)] and anterior regions [17.9 mm (12.2-20.7)] compared with the posterior [21.9 mm (18.6-24.0)] segment. Values in MVA were smaller than in TVA, slightly higher in anterior [11.2 mm (9.5-13.0)] than in posterior [12.4 mm (10.2-14.6)] segments. Valvular regurgitation was associated with enlarged, flattened, and more circular annuli. CONCLUSION: The applied method was feasible and accurate in normal and regurgitant valves, and may potentially have an impact on diagnosis, improvement of surgical techniques and design of annular prostheses.

European Association of Echocardiography recommendations for the assessment of valvular regurgitation. Part 2: mitral and tricuspid regurgitation (native valve disease).

Mitral and tricuspid are increasingly prevalent. Doppler echocardiography not only detects the presence of regurgitation but also permits to understand mechanisms of regurgitation, quantification of its severity and repercussions. The present document aims to provide standards for the assessment of mitral and tricuspid regurgitation.

Three-dimensional echocardiography. New possibilities in mitral valve assessment.

Recent developments in three-dimensional echocardiography have made it possible to obtain images in real time, without the need for off-line reconstruction. These developments have enabled the technique to become an important tool for both research and daily clinical practice. A substantial proportion of the studies carried out using three-dimensional echocardiography have focused on the mitral valve, the pathophysiology of mitral valve disease and, in particular, functional mitral regurgitation. The aims of this article were to review the contribution of three-dimensional echocardiography to understand the functional anatomy of the mitral valve and to summarize the resulting clinical applications and therapeutic implications.

Assessment of coronary sinus anatomy between normal and insufficient mitral valves by multi-slice computertomography for mitral annuloplasty device implantation.

INTRODUCTION: Latest techniques enable positioning of devices into the coronary sinus (CS) for mitral valve (MV) annuloplasty. We evaluate the feasibility of non-invasive assessment to determine CS anatomy and its relation to MV annulus and coronary arteries by multi-slice CT (MSCT) in normal and insufficient MV. METHODS: Fifty patients (33 males, 17 females, age 67+/-11 years) were studied retrospectively by 64-MSCT scans for anatomical criteria regarding CS and its relation to MV annulus and circumflex artery (CX). We included 24 patients with severe mitral insufficiency and 26 with no MV disease. Diameter of MV, of proximal and distal ostium of CS, length and volume of CS, angle between anterior interventricular vein (AIV) and CS, caliber change of CX before, under/over and after CS were analysed. Different anatomical correlations were demonstrated: distance of MV annulus to CS, CX to CS. RESULTS: Diameter of proximal CS ostium was significantly larger in insufficient MV compared to normal MV (11+/-2.8 mm vs 9.9+/-2.5 mm; p<0.024). CS was significantly longer in patients with insufficient MV (125.4+/-17 mm vs 108.9+/-18 mm; p<0.003) with also significant differences in volume of CS (p<0.039). Significant difference in annulus diameter, 46.1+/-6mm (insufficient MV) versus 39.5+/-7.5 mm, p<0.004 was observed. Angle CS-AIV was 103.5+/-29 degrees (range 52 degrees -144 degrees ) in insufficient valves versus 118.2+/-24.5 degrees (range 73 degrees -166 degrees ) in normal valves with a tendency to higher angles in normal valves (p=0.06). Distance of MV annulus to CS measured 16+/-4.1/14.2+/-3.6 mm (insufficient/normal MV) without significant difference between groups. In 15 patients CX ran under CS. Eighty-four percent of these patients (13/15) show a decrease in CS caliber in the area of intersection. In 14 patients CS ran over and in one patient the diameter of the CS at intersecting region was smaller. In 16 patients no direct point of contact was visible, in five patients CX to CS positioning was not evaluable. CONCLUSION: There is a significant anatomic difference between normal and insufficient MV, which might be the basis for any interventional approaches through the CS. Exact measurements of all structures and its anatomic correlations are possible with MSCT, which allows pre-interventional planning.

Assessment of the tilting properties of the human mitral valve during three main phases of the heart cycle: an echocardiographic study.

RATIONALE AND OBJECTIVES: In experimental models of the left heart, the mitral valve (MV) is commonly implanted perpendicular to a central axis of the apex/MV. To adapt this to a more correct anatomical model, as well as for further studies of the left ventricle, we created a database of implantation angles of the MV and annulus during three main phases of the heart cycle, based on standard cardiac ultrasound measurements. MATERIALS AND METHODS: Twenty-eight patients were studied with the standard cardiac ultrasound equipment. From the apical echo window, an anteroposterior (AP) plane and a perpendicular commisure-commisure (CC) plane were generated during three critical moments in the heart cycle: systole (S); diastole early filling (E); and diastole late filling (A). In both planes, the angles between the annular plane and each mitral leaflet, as well as the angle between a theoretical longitudinal axis through the apex and center of the MV orifice and the mitral annulus plane, were measured with a custom-made application of Matlab R14. RESULTS: We observed an inclination of the angle mitral annulus/central left ventricle axis, with its lowest point in the direction of the aortic valve (AP plane) of 85 degrees+/-7 degrees in systole (S), 88 degrees+/-8 degrees in early diastole (E), and 88 degrees+/-7 degrees in late diastole (A). In the CC plane, we observed an almost horizontal implantation of 91 degrees+/-5 degrees in systole (S), 91 degrees+/-8 degrees in early diastole (E), and 91 degrees+/-7 degrees in late diastole (A).

Quantitative assessment of velocities of the annulus of the left atrioventricular valve and left ventricular free wall in healthy cats by use of two-dimensional color tissue Doppler imaging.

OBJECTIVE: To analyze velocities of the annulus of the left atrioventricular valve and left ventricular free wall (LVFW) in a large population of healthy cats by use of 2-dimensional color tissue Doppler imaging (TDI). ANIMALS: 100 healthy cats (0.3 to 12.0 years old; weighing 1.0 to 8.0 kg) of 6 breeds. PROCEDURE: Radial myocardial velocities were recorded in an endocardial and epicardial segment, and longitudinal velocities were recorded in 2 LVFW segments (basal and apical) and in the annulus of the left atrioventricular valve. RESULTS: LVFW velocities were significantly higher in the endocardial than epicardial layers and significantly higher in the basal than apical segments. For systole, early diastole, and late diastole, mean +/- SD radial myocardial velocity gradient (MVG), which was defined as the difference between endocardial and epicardial velocities, was 2.2 +/- 0.7, 3.3 +/- 1.3, and 1.8 +/- 0.7 cm/s, respectively, and longitudinal MVG, which was defined as the difference between basal and apical velocities, was 2.7 +/- 0.8, 3.1 +/- 1.4, and 2.1 +/- 0.9 cm/s, respectively. A breed effect was documented for several TDI variables; therefore, reference intervals for the TDI variables were determined for the 2 predominant breeds represented (Maine Coon and domestic shorthair cats). CONCLUSIONS AND CLINICAL RELEVANCE: LVFW velocities in healthy cats decrease from the endocardium to the epicardium and from the base to apex, thus defining radial and longitudinal MVG. These indices could complement conventional analysis of left ventricular function and contribute to the early accurate detection of cardiomyopathy in cats.

Annular geometry and motion in human ischemic mitral regurgitation: novel assessment with three-dimensional echocardiography and computer reconstruction.

BACKGROUND: Annular geometry and motion in functional ischemic mitral regurgitation are incompletely understood. Three-dimensional echocardiography demonstrates saddle-shaped annular geometry, but standard methodology does not enable quantification of annular motion. Therefore, a novel technique using three-dimensional echocardiography and computer software was used to characterize alterations in mitral annular geometry and motion in patients with ischemic mitral regurgitation. METHODS: We developed a computer program to reconstruct the mitral annulus based on spatial coordinates from three-dimensional echocardiography. Data were obtained at end-diastole and end-systole in 7 patients with ischemic mitral regurgitation and 5 normal control subjects. Mitral annular motion was quantified by calculating the displacement area of the annulus between end-diastole and end-systole. RESULTS: Comparison of ischemic mitral regurgitation and control patients revealed differences in annular geometry and motion at end-diastole. Annular perimeter was greater in ischemic mitral regurgitation patients (10.7 +/- 0.7 cm versus 8.6 +/- 0.2 cm in control group; p < 0.03), with increased intertrigonal distance in ischemic mitral regurgitation patients (2.8 +/- 0.3 cm versus 2.1 +/- 0.1 cm; p < 0.06). These changes resulted in increased annular orifice area in ischemic mitral regurgitation patients (9.1 +/- 1.2 cm2 versus 5.7 +/- 0.3 cm2; p < 0.03). Ischemic mitral regurgitation patients had altered annular motion, with reduced movement of the posterior annulus (5.4 +/- 0.7 cm2 versus 8.7 +/- 1.1 cm2; p < 0.03). CONCLUSIONS: Computer analysis of data obtained from three-dimensional echocardiography demonstrates altered annular geometry and motion in patients with ischemic mitral regurgitation. Patients with ischemic mitral regurgitation have annular dilatation, with an increase in anterior and posterior annular perimeters; this is accompanied by an increase in the intertrigonal distance and restriction of annular motion.

Experimental and clinical assessment of mitral annular area and dynamics: what are we actually measuring?

The mitral annulus is an essential, dynamic, and tightly coupled component of the mitral valve/left atrial/left ventricular complex that aids in effective and efficient valve closure and unimpeded left ventricular filling. Although the dynamic nature of mitral annular motion has been studied carefully for more than 30 years, accurate measurement of mitral annular area and motion continues to be a challenge for physiologists and clinicians alike. Roentgenographic ciné imaging of radiopaque markers, sonomicrometry, magnetic resonance imaging, and two-dimensional echocardiography have all been used to evaluate mitral annular area and dynamics, yet widely disparate measurements abound. Paradoxically, newer three-dimensional transesophageal echocardiographic findings may have added to this miasma. To explore the variability of these measurements, we reviewed our experimental data as well as clinical and experimental observations reported in the literature to clarify what we are actually measuring and perhaps explain the reported disagreement. The objective was to shed some light on the possible reasons for these discordant findings.

Echocardiographic assessment of mitral regurgitation.

Although the natural history of mitral regurgitation (MR) is poorly defined, evidence has been found for excess mortality and morbidity in patients with severe MR who are managed conservatively. With improved mortality and morbidity in the surgical management of this condition, we are becoming increasingly aggressive in offering surgery to patients with severe MR. Surgery may be offered even in the absence of symptoms or left ventricular dysfunction, provided that the valve seems reparable, the patient's MR is severe, and the surgical team is experienced in valve repair. Echocardiography is critically important in determining the feasibility of valve repair and accurately assessing the severity of the patient's MR. It also allows assessment of the effect of MR on the left ventricle and the left atrium.

Three-dimensional echocardiographic assessment of annular shape changes in the normal and regurgitant mitral valve.

OBJECTIVES: To compare mitral annular shape and motion throughout the cardiac cycle in patients with normal hearts versus those with functional mitral regurgitation (FMR). BACKGROUND: The causes of mitral regurgitation without valvular disease are unclear, but the condition is associated with changes in annular shape and dynamics. Three-dimensional (3D) imaging provides a more comprehensive view of annular structure and allows accurate reconstructions at high spatial and temporal resolution. METHODS: Nine normal subjects and 8 patients with FMR undergoing surgery underwent rotationally scanned transesophageal echocardiography. At every video frame of 1 sinus beat, the mitral annulus was manually traced and reconstructed in 3D by Fourier series. Annular projected area, nonplanarity, eccentricity, perimeter length, and interpeak and intervalley spans were determined at 10 time points in systole and 10 points in diastole. RESULTS: The mitral annulus in patients with FMR had a larger area, perimeter, and interpeak span than in normal subjects (P <.001 for all). At mid-systole in normal annuli, area and perimeter reach a minimum, nonplanarity is greatest, and projected shape is least circular. These cyclic variations were not significant in patients with FMR. Annular area change closely paralleled perimeter change in all patients (mean r = 0.96 +/- 0.07). CONCLUSIONS: FMR is associated with annular dilation and reduced cyclic variation in annular shape and area. Normal mitral valve function may depend on normal annular 3D shape and dimensions as well as annular plasticity. These observations may have implications for design and selection of mitral annular prostheses.

Doppler echocardiographic assessment with the continuity equation of St. Jude Medical mechanical prostheses in the mitral valve position.

Evaluation of the St. Jude Medical (SJM) valve in the mitral position with Doppler echocardiography has usually involved the use of gradients across the valve and the application of the pressure half-time (PHT) method to derive a mitral valve area. The purpose of this study was, first, to determine the normal values of effective orifice areas for the SJM valve in the mitral position using the continuity equation, and second, to evaluate whether this parameter provides an improved assessment of valve function. Accordingly, Doppler echocardiography was performed in 40 patients within 6 weeks after valve replacement. All patients were clinically stable, without evidence of valvular dysfunction or aortic insufficiency. Valve size ranged from 23 to 33 mm and ventricular ejection fraction averaged 54 +/- 13%. Effective orifice area was derived by the continuity equation using stroke volume measured in the ventricular outflow tract, divided by the time-velocity integral of the SJM valve jet, and by PHT. Doppler-derived SJM valve mean gradient averaged 4 +/- 2 mm Hg. Effective area by the continuity equation averaged 1.82 +/- 0.36 cm2 (range 1.03 cm2 for a 23 mm valve to 2.63 cm2 for a 31 mm valve) and was smaller than by PHT (mean 3.10 +/- 0.65 cm2, p = 0.0001; range 1.38 to 4.78 cm2). Areas by both methods were smaller than the actual valve orifice area provided by the manufacturer (4.53 +/- 0.80 cm2, p = 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)