However, colour Doppler is currently not available with live 3D imaging. As with all echocardiography techniques, 3D methods are still dependent on obtaining an adequate echo window. Measurements can be made of distance or area from any 2D plane within the 3D data set, but direct measurements from the 3D image display are currently not possible, although an appreciation of size can be made by overlaying a grid of known dimensions.
The time taken for analysis previously limited its clinical utility: This was further hampered by artefacts produced in the data set from irregular cardiac cycles and respiration. The first realtime probes to become available were capable of transthoracic 3D 3D transthoracic echocardiography [TTE] imaging but had limitations due to suboptimal image display. With the introduction of transeosphageal 3D 3D transeosphageal echocardiography [TEE] , realtime imaging, probe image quality, acquisition and analysis of the data sets can be performed online within seconds.
Imaging in 3D provides clear appreciation of the true shape of cardiac structures and the spatial relationships between them. Full evaluation of valvular heart disease, whether for diagnosis or for planning of an intervention, requires accurate delineation of the actual valve pathology but also assessment of any consequent cardiac dysfunction, including assessment of ventricular size and function. The clinical utility of 3D echocardiography in valvular disease is well illustrated by its use in mitral valve disease, which will be covered in more detail below.
The role of 3D echocardiography in the assessment of mitral regurgitation is best understood in terms of the assessment of valve morphology aetiology and mechanism and then assessment of the severity of regurgitation. Mitral regurgitation can arise from a variety of mechanisms that may occur in combination.
Guidelines emphasise the benefits of valve preservation by repair on patient outcomes. This helps to guide the decision on the best time to intervene and offer surgery; this has become increasingly relevant as mitral repair is being performed in asymptomatic patients with severe mitral regurgitation. Assessment of the mitral valve by 2D echocardiography requires the operator to obtain multiple views through all segments of the two leaflets.
This requires considerable expertise and experience, but even then errors in interpretation may occur. This is unobtainable with the 2D approach. The resolution is optimal from these windows since the mitral valve is in close proximity to the probe. The live image is rotated to view the left atrial aspect of the mitral valve and the image is optimised by gentle probe angulation to bring the leaflets, coaptation line and annulus into view in their entirety.
Visualising the heart from the transthoracic approach means one of the main limitations is image quality. Frame rates and image resolution are the main factors that limit precise details of valve anatomy. However, in the majority of patients at least adequate image quality allows a useful and rapid overview of the valve morphology.
The extent of any prolapsing or restricted leaflet segments, the commissures, leaflet coaptation line and mitral annulus can be seen. Again, the parasternal long-axis window is preferred as anatomical landmarks using standardised analysis protocols mean this approach is simple and reproducible; 6 where such windows are poor, the apical windows can be used. Rapid online segmental analysis can be performed by viewing the data set in a multiplanar reconstruction format to define short- and long-axis views of the mitral valve.
Using established landmarks, the entire coaptation line can be assessed from the anterolateral commissure, P1 and A1 segments through P2, A2 and then P3, A3 and the posteromedial commissure. The relationship of each segment to the annulus can be accurately assessed. Measurements can be made of segment prolapse or tenting 7 in relation to the annulus.
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Acquisition times and the time needed for analysis of the data sets are reasonable and can easily be incorporated into the standard 2D echocardiography examination. Figure 1 gives an example of segmental analysis. The literature confirms the clinical utility of 3D echocardiography in mitral valve morphology diagnosis. They performed a comprehensive 3D protocol taking views from both parasternal and apical windows. A more focused approach with the acquisition of two 3D images a realtime 3D image and a full-volume data set can reduce these times further. With the huge step up in image resolution offered by 3D TEE, an authentic depiction of mitral valve anatomy can now be viewed in vivo and in realtime.
New levels of understanding of valve morphology are now possible. Since the closest cardiac structure to the probe in TEE is the left atrium, replicating the surgical view is rapid and straightforward. The VC is defined as the smallest, highest-velocity region of a flow jet and is typically located at or just below the regurgitant orifice. Its width should be measured in a long-axis imaging plane perpendicular to the mitral leaflet closure.
The VC is independent of flow rate and driving pressure. It can be used for central and eccentric jets and is accurate in acute MR. However, it is not valid for multiple jets. Intermediate values of VC width 0. However, increased left atrial pressure of any cause can result in blunted pulmonary venous systolic flow Figure 1D. Absence of flow reversal should not be used for exclusion of significant MR. It can be false negative if the jet is directed away from pulmonary veins, e. On the other hand, if the MR jet is small but eccentric and directed towards the pulmonary vein, blunted or reverse flow can be recorded in this pulmonary vein false positive.
A non-geometric pulsed Doppler index, namely the mitral to aortic velocity-time integral VTI , is used for quantification of pure isolated organic MR. The flow acceleration proximal to the regurgitant orifice results in a concentric proximal isovelocity surface area PISA. PISA is based on the fact that, near the regurgitant orifice, the blood is disposed in hemispheric layers, having the same velocity at a certain distance from the orifice.
Measuring the first aliasing hemisphere is a marker of regurgitation degree [3]. Four formulas are used for calculation:.
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Quantification of RV and regurgitant fraction RF is based on calculation of stroke volume SV across the MV and across another non-regurgitant valve aortic or pulmonic. The formula used for SV calculation is: Subtraction of the SV obtained at two sites is used to calculates RV. ROA can also be obtained by the formula: To calculate SV across the aortic valve, a parasternal long-axis view is used to measure LV outflow tract LVOT diameter at the level of the aortic valve annulus, just proximal to the cusps, and an apical 5-chamber view to measure the VTI of the LVOT using pulsed wave Doppler placing the sample volume at the level of the same point where the LVOT diameter was measured.
Methods used for MR quantification. The criteria used to define severe MR using previous parameters are displayed in Table 1. Considering the profound deleterious effect of ischaemic MR, the cut-off levels of severity are lower than in organic MR [4]. Echocardiographic semi-quantitative and quantitative parameters used to define severe MR. Using the apical 2-chamber view, which is oriented parallel to the line of leaflet coaptation, a wide VC may show even in mild MR [5].
As a general rule, 2D transthoracic echocardiography 2D-TTE is enough for the assessment of MR severity and clarification of the mechanism.
3D Echocardiography in Mitral Valve Heart Disease - Is It the New Gold Standard?
Before MV surgery, TEE is usually required for better understanding of the mechanism of MR and selecting the proper reparative strategy or replacement according to the descriptive morphology of the MV apparatus. In organic MR, an "en face" view of the MV from both atrial and ventricular aspects can be easily displayed using 3D echo. This helps in detailed visualisation of the anatomic features of the MV apparatus. It has been proved that 3D echo is highly accurate and reproducible in localising prolapsing scallops.
Not only qualitative assessment but also many of the parameters can be obtained including:. This is indicated if there is a discrepancy between symptoms and the severity of MR at rest, e. It can evaluate contractile reserve and other metrics such as functional capacity and exercise-induced pulmonary hypertension which may have prognostic value. Acute ischaemic MR is more often due to complete or partial rupture of the papillary muscle, and less frequently due to an elongation of the muscle.
Clues for the diagnosis of acute MR by echocardiography include dense Doppler signals, a wide VC and high filling pressure despite normal LV cavity size. Careful visualisation of chordae and papillary muscles using off-axis views is crucial for the diagnosis and for identifying the mechanism.
Echocardiography in mitral valve disease: a review.
Partial rupture of papillary muscles can be missed and misdiagnosed as MV prolapse. Echocardiography 2D and 3D via transthoracic and transoesophageal approaches plays an important role in the assessment of mitral valve disease MVD. Echocardiographic assessment can be classified into qualitative, quantitative and semi-quantitative. This includes the morphological assessment of MV leaflets and subvalvular apparatus.
This assessment helps in identification of the underlying aetiology of MS organic [mainly rheumatic], or congenital. The main features can be summarised as follows:. This assessment helps in the grading of MS severity and identifying the stages Table 1. The following parameters are mandatory:. Post-balloon valvuloplasty, both qualitative and quantitative echo parameters are used to evaluate the outcome and to predict event-free survival. These morphological features are used by different scoring systems [11] to evaluate the suitability for percutaneous mitral balloon valvuloplasty PMBV and to predict success.
The Wilkins score is widely used by interventionists Table 2. S emi-quantification of mitral valve morphology according to the Wilkins score. In asymptomatic patients or in patients in whom the symptoms and MS severity do not seem to correlate, stress echo preferably exercise or alternatively dobutamine infusion is indicated [12]. It provides additional information through assessing mitral gradients and pulmonary pressures during stress. In general, TEE provides higher resolution and better assessment of the MV apparatus especially chordae.
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The morphologic assessment of MV leaflets can be obtained from the mid-oesophageal level scanning from 0 degrees to degrees while transgastric views from 90 degrees to degrees is better for visualisation of chordae. Doppler measurements can be obtained from mid-oesophageal views. Three-dimensional echocardiography is useful in enhancing the objective assessment of MV morphology from a single imaging plane [12].
It enables visualisation of the narrowest orifice of the MV through better alignment of the image plane at the mitral tips Figure 2D. The 3D-derived MVA is accurate and reproducible with excellent interobserver and intraobserver agreement. A validated scoring system by 3D echo can be used for the decision on balloon mitral valvotomy [11]. Mitral annular calcification is relatively common in older patients. It most commonly occurs in the posterior part of the mitral annulus and extends to the posterior leaflet.
In massive calcification, extension into the mitral leaflets can cause significant MS. Circ Cardiovasc Imaging ;6: Lancellotti P, Magne J. Stress echocardiography in regurgitant valve disease. Exercise-induced changes in degenerative mitral regurgitation. Prognostic importance of exercise-induced changes in mitral regurgitation in patients with chronic ischemic left ventricular dysfunction.
Long-term outcome of patients with heart failure and dynamic functional mitral regurgitation. Recommendations for the echocardiographic assessment of native valvular regurgitation: An executive summary from the european association of cardiovascular imaging. Contribution of exercise-induced mitral regurgitation to exercise stroke volume and exercise capacity in patients with left ventricular systolic dysfunction.
Quantitation of functional mitral regurgitation during bicycle exercise in patients with heart failure. The role of ischemic mitral regurgitation in the pathogenesis of acute pulmonary edema.
N Engl J Med ; Determinants of exercise-induced changes in mitral regurgitation in patients with coronary artery disease and left ventricular dysfunction. Clinical significance of exercise pulmonary hypertension in secondary mitral regurgitation. Am J Cardiol ; Coronary artery bypass surgery with or without mitral valve annuloplasty in moderate functional ischemic mitral regurgitation: Final results of the randomized ischemic mitral evaluation RIME trial.
Efficacy of adding mitral valve restrictive annuloplasty to coronary artery bypass grafting in patients with moderate ischemic mitral valve regurgitation: J Thorac Cardiovasc Surg ; Two-year outcomes of surgical treatment of moderate ischemic mitral regurgitation. Advanced Search Users Online: How to cite this article: Role of stress echocardiography in mitral valve disease.
How to cite this URL: Stress Echocardiography in Mitral Stenosis. Indications for performing stress echocardiography in mitral valve disease Click here to view. Interpretation and implications of stress echocardiography findings in mitral stenosis Click here to view. Exercise stress echocardiography in a year-old man with isolated, rheumatic mitral stenosis who presented with significant exertional dyspnea.
The patient developed significant dyspnea at 5. Mitral valve area, TR: Tricuspid regurgitation Click here to view. Another patient with mild to moderate rheumatic mitral stenosis who presented with significant exertional dyspnea.