Mitral Stenosis

Rheumatic disease predominantly affects the mitral valve and is nearly always the cause of mitral stenosis. (Otto, Clinical Echocardiography 6e)

The most common cause of mitral stenosis (MS) is rheumatic fever, even in industrialized countries, followed by degenerative MS. Congenital MS, malignant carcinoid disease, inflammatory diseases, infiltrative diseases, tumours, or drug-induced valve disease represent rare causes of MS. (EACVI Textbook of Echocardiography)

The most common cause of MS is rheumatic fever (approximately 10% VHD in Europe and North America), with other causes (congenital, inflammatory/infiltrative) occurring only rarely. (Oxford Critical Care Echo)

As the degree of valve opening decreases, the increasing obstruction to blood flow results in an increased flow velocity and pressure gradient across the valve. In isolated valve stenosis, clinical symptoms typically occur when the valve orifice is reduced to one quarter its normal size. (Otto, Clinical Echocardiography 6e)

The echocardiographic diagnosis of MS includes demonstrating a structural abnormality of leaflets (and/or subvalvular apparatus), together with an increase in blood velocity across the valve measured using Doppler. (Oxford Critical Care Echo)

The normal valve area is 4-6 cm2. Current guidelines consider MS significant when MVA is less than 1.5 cm2. (EACVI Textbook of Echocardiography)

Rheumatic valvular disease is characterized by commissural fusion, which results in bowing or doming of the valve leaflets in diastole. The base and mid-sections of the leaflets move toward the ventricular apex, whereas the motion of the leaflet tips is restricted because of fusion of the anterior and posterior leaflets along the medial and lateral commissures. (Otto, Clinical Echocardiography 6e)

The rheumatic process also typically affects the subvalvular region with fusion, shortening, fibrosis, and calcification of the mitral chordae. (Otto, Clinical Echocardiography 6e)

In rheumatic disease, echocardiography shows leaflet thickening with restricted opening caused by commissural fusion resulting in 'doming' of the mitral valve (MV) in diastole. This is usually best seen in the parasternal long-axis view, while commissural fusion can be appreciated in the parasternal short-axis view. (EACVI Textbook of Echocardiography)

Loss of leaflet mobility. This occurs as a consequence of commissural fusion, and chordal shortening and tethering, and it creates the appearance of diastolic doming of the body of the anterior mitral leaflet (the 'hockey stick' sign). (Practical Perioperative TOE)

The hallmarks of rheumatic mitral stenosis include the following: Leaflet thickening, particularly of the commissures and leaflet edges; Loss of leaflet mobility; Leaflet calcification; Subvalvular involvement. The chordae appear shortened, tethered, and on occasion, calcified. (Practical Perioperative TOE)

Fused leaflet tips and a 'hockey stick' appearance of the anterior mitral leaflet implicate rheumatic fever, whereas marked mitral annular echodensities implicate mitral annular calcification. (Essential Echocardiography)

Mitral annular calcification is a common finding on echocardiography in older adults. Mild annular calcification appears as an isolated area of calcification on the LV side of the posterior annulus, near the base of the posterior mitral leaflet. (Otto, Clinical Echocardiography 6e)

Occasionally, the calcification extends into the base of the mitral leaflets themselves, thus resulting in functional mitral stenosis due to narrowing of the diastolic flow area. (Otto, Clinical Echocardiography 6e)

Calcific mitral stenosis can be distinguished from rheumatic disease by careful imaging techniques that demonstrate thin and mobile mitral leaflet tips without commissural fusion. (Otto, Clinical Echocardiography 6e)

In degenerative MS, calcifications affect predominantly the annulus and the base of the leaflets. (EACVI Textbook of Echocardiography)

Conventional methods for assessment of MS severity, especially valve area measurements, are not helpful in degenerative MS. Mean mitral gradient in stable loading conditions is a better diagnostic tool in this setting. Degenerative MS is most often mild/moderate, and rarely severe. (EACVI Textbook of Echocardiography)

The LV in mitral stenosis is small with normal wall thickness and normal systolic function, although diastolic function is impaired because of the restriction of flow across the mitral orifice. (Otto, Clinical Echocardiography 6e)

Chronic pressure overload of mitral stenosis leads to gradual enlargement of the LA. LA size can become extremely large in long-standing severe mitral stenosis. In conjunction with a low volume flow rate due to the stenotic valve, LA enlargement results in stasis of blood flow and thrombus formation. (Otto, Clinical Echocardiography 6e)

In mitral stenosis, increased LA pressure results in pulmonary venous hypertension and consequent pulmonary artery hypertension. Initially, the increase in pulmonary artery pressure is 'passive'. With long-standing pulmonary venous hypertension, irreversible changes in the pulmonary vascular bed occur, leading to elevated pulmonary vascular resistance and persistent pulmonary hypertension after relief of mitral stenosis. (Otto, Clinical Echocardiography 6e)

Severe mitral stenosis may be associated with a low stroke volume (due to the limitation of LV diastolic filling), resulting in a relatively low mean gradient. If volume flow rate increases, for example, with exercise, an increase in transmitral gradient is seen. (Otto, Clinical Echocardiography 6e)

This enlargement may predispose the patient to atrial fibrillation and its pathological sequelae, such as thromboembolism. Elevated LA pressure is also transmitted back to the pulmonary vasculature. Although initially reversible, these elevated pressures may become largely fixed as the pulmonary vasculature remodels, and permanent pulmonary hypertension can ensue. (Essential Echocardiography)

Work through it in a logical order: define the valve morphology and the mechanism and aetiology of obstruction, build severity from qualitative signs to quantitative measures (valve area and mean gradient, always at a documented heart rate), assess the secondary effects on the left atrium, pulmonary pressures and right heart, then integrate with the clinical picture and rhythm — judging morphology for suitability for percutaneous commissurotomy.

In rheumatic mitral stenosis, 2D and 3D echo allows for detailed evaluation of mitral valve morphology, including assessment of leaflet thickness, leaflet mobility, the degree of calcification, and the extent of subvalvular involvement on TTE parasternal and apical views. (Otto, Clinical Echocardiography 6e)

This is usually best seen in the parasternal long-axis view, while commissural fusion can be appreciated in the parasternal short-axis view. (EACVI Textbook of Echocardiography)

The peak and mean mitral gradients are obtained by tracing the continuous wave Doppler diastolic mitral flow spectrum in the apical four-chamber view using the simplified Bernoulli equation. (EACVI Textbook of Echocardiography)

The mitral stenosis jet nearly always can be recorded from an apical approach, but careful transducer positioning and angulation are needed to record an optimal signal. Color flow imaging may be helpful in defining the jet direction in a given tomographic plane. (Otto, Clinical Echocardiography 6e)

Leaflet morphology and diastolic doming are best appreciated in the midesophageal five-chamber and long-axis views. Subvalvular involvement is usually best visualized from the transgastric two-chamber view. (Practical Perioperative TOE)

Among 2D TTE standard views, the parasternal short axis is the best approach to analyse overall mitral valve tissue, providing a simultaneous visualization of the commissures, leaflets, and related subvalvular suspension system. (EACVI Textbook of Echocardiography)

The Wilkins score evaluates leaflet mobility and thickening, the amount of MV calcifications, and subvalvular thickening, with grading from 1 to 4 points for each component. A Wilkins score higher than 8 predicts a lower success rate for PMC. (EACVI Textbook of Echocardiography)

Mitral valve morphology may be described by a qualitative assessment, an additive scoring system, or quantitative measurements of leaflet mobility. Whatever approach is used, the important features to consider are leaflet mobility, leaflet thickness, leaflet and commissural calcification, and subvalvular involvement. (Otto, Clinical Echocardiography 6e)

The MV score, which is derived from the morphology of the MV and its supporting structures, helps to more objectively guide this decision by predicting the outcome after PMV. Overall, as the MV score increases, the potential for procedural success decreases. A valve score of less than eight is associated with a good outcome. (Essential Echocardiography)

Scoring system derived from description of the above four parameters with a score of 1 for near-normal and 4 for the extensive involvement. An echocardiographic score of 8 or less, predicts better outcome of percutaneous mitral valvuloplasty. (Essential Echocardiography)

In general, the best hemodynamic results are seen with thin, mobile leaflets that have commissural fusion but little calcification or subchordal thickening. (Otto, Clinical Echocardiography 6e)

In the potential candidate for percutaneous balloon mitral commissurotomy, echo Doppler evaluation of mitral valve morphology is important in patient selection both in terms of predicted hemodynamic results and in terms of the risk of procedural complications. (Otto, Clinical Echocardiography 6e)

Contraindications to PMC: MVA greater than 1.5 cm2; LA thrombosis; mitral regurgitation greater than mild; severe/bicommissural calcification; absence of commissural fusions; aortic disease/severe tricuspid regurgitation; coronary artery disease requiring surgery. (EACVI Textbook of Echocardiography)

The use of TOE is most often required to properly assess MV morphology, to rule out LA thrombi or significant MR. (EACVI Textbook of Echocardiography)

Two factors whose presence weigh strongly against (if not preclude) proceeding with PMV are co-existent LA thrombus and moderate to severe mitral regurgitation. First, a LA thrombus may become dislodged and embolize during PMV. Secondly, mitral regurgitation may be increased by PMV. (Essential Echocardiography)

A thin mobile noncalcified MV without subvalvular thickening is amenable to PMV. Whereas, a thickened, nonmobile, calcified MV with subvalvular thickening is not a good PMV candidate. (Essential Echocardiography)

Patients presenting for surgical correction are those who have valvular features unsuitable for this technique, including extensive leaflet and subvalvular calcification, mitral or tricuspid regurgitation, and LA thrombus development. (Practical Perioperative TOE)

The mean diastolic transmitral pressure gradient can be determined from the transmitral velocity curve using the simplified Bernoulli equation. (Otto, Clinical Echocardiography 6e)

The peak gradient derives from the peak mitral velocity which is also influenced by LA compliance, LV diastolic function, and loading conditions. Therefore, the mean gradient is the more relevant haemodynamic parameter. Yet, this is not the most reliable marker of MS severity as it is highly flow- and rate-dependent, being influenced by heart rate, cardiac output, and associated mitral regurgitation (MR). (EACVI Textbook of Echocardiography)

Thus, the heart rate at which pressure gradients are measured should always be reported. In patients with atrial fibrillation (AF), an average of five cardiac cycle gradient measurements, as close as possible to the normal heart rate, should be calculated. (EACVI Textbook of Echocardiography)

The variability in pressure gradients in severe mitral stenosis is due to the dependence of pressure gradients on the volume flow rate in addition to valve area. (Otto, Clinical Echocardiography 6e)

Note that pressure gradients are also increased by elevated cardiac output, mitral regurgitation, and restrictive diastolic filling. (Practical Perioperative TOE)

Calculation of mitral valve area by the pressure half-time method is based on the concept that the rate of pressure decline across the stenotic mitral orifice is determined by the cross-sectional area of the orifice: the smaller the orifice, the slower the rate of pressure decline. (Otto, Clinical Echocardiography 6e)

Initial studies comparing Doppler half-time data with invasively determined Gorlin valve areas found a linear relationship, with a half-time of approximately 220 ms corresponding to a valve area of 1 cm2. (Otto, Clinical Echocardiography 6e)

The pressure half-time (PHT) method is the simplest approach to estimate the functional MVA using Doppler echocardiography. The time required for the peak gradient to drop to one-half (PHT) is related to the severity of MS: the more severe the obstruction, the longer the PHT. MVA is derived from the PHT using the empirical formula: MVA = 220/PHT. (EACVI Textbook of Echocardiography)

PHT is measured by tracing the deceleration slope of the E wave on the spectral Doppler display of mitral inflow. The use of continuous wave Doppler recordings and tracing of modal velocities are recommended. (EACVI Textbook of Echocardiography)

The pressure half-time is the time it takes (in milliseconds) for the transmitral gradient to halve from its initial maximum, and is inversely proportional to the valve area, where MVA = 220/PHT. (Oxford Critical Care Echo)

Grading MS should combine the measurements of MVA (using planimetry and PHT) and mean mitral gradient. Planimetry is the reference method in case of discrepancy. The normal valve area is 4-6 cm2. Current guidelines consider MS significant when MVA is less than 1.5 cm2. (EACVI Textbook of Echocardiography)

Evaluation of mitral stenosis severity: Valve area (cm2) Mild >1.5, Moderate 1.0-1.5, Severe <1.0; Mean gradient (mmHg) Mild <5, Moderate 5-10, Severe >10 (in sinus rhythm and in the absence of tachycardia). (Oxford Critical Care Echo)

Some general categories for the mean gradient are as follows: Mean gradient 0-5 mmHg (mild stenosis), 5-10 mmHg (moderate stenosis), >10 mmHg (severe stenosis). (Essential Echocardiography)

The presence of pulmonary hypertension suggests significant MS in the absence of an alternative explanation. However, normal resting values of pulmonary artery pressure may be observed even in severe MS. (EACVI Textbook of Echocardiography)

With severe stenosis, the mean pressure gradient may be as high as 20 to 30 mmHg, but often it is only 5 to 15 mmHg. (Otto, Clinical Echocardiography 6e)

Planimetry of the MV orifice provides the anatomical mitral valve area (MVA). It is considered the reference method to determine MVA, as it is a direct measurement and is relatively load-independent. (EACVI Textbook of Echocardiography)

Three-dimensional echocardiography is more precise for measuring the MVA since it allows direct visualization of the valve orifice in multiple planes to ensure that the smallest valve orifice at the tip of the mitral leaflets is being measured. When possible, the 3D-guided measurement of MVA is recommended. (EACVI Textbook of Echocardiography)

Because the shape of the mitral valve inflow region is similar to a funnel, with the narrowest cross-sectional area at the leaflet tips, if 2D imaging is used, it is important that the scan start apically, slowly moving the image plane toward the mitral valve to identify the smallest orifice. (Otto, Clinical Echocardiography 6e)

Continuity equation mitral valve area determinations are most accurate in patients without significant coexisting mitral regurgitation. In this subgroup, continuity equation mitral valve area calculations provide a useful alternative to the pressure half-time method, especially in situations of altered chamber compliances. (Otto, Clinical Echocardiography 6e)

Planimetry of the mitral valve orifice taken from the SAX view has the best correlation of MVA, and when undertaken by experienced echocardiographers is regarded as the gold standard against which other measurements should be referenced. (Oxford Critical Care Echo)

In theory, transmitral volume flow rate can be calculated accurately in mitral stenosis even when mitral regurgitation is present using the proximal isovelocity surface area method. Because of this problem, the proximal isovelocity method has not been widely applied in mitral stenosis. (Otto, Clinical Echocardiography 6e)

The influence of LA and LV compliance on the rate of pressure decline is assumed to be negligible, an assumption that is not always warranted, especially immediately after percutaneous commissurotomy. (Otto, Clinical Echocardiography 6e)

In situations when LA pressure drops more rapidly (atrial septal defect or low LA compliance), the PHT is shortened and the MVA will be overestimated. When LV compliance is reduced (LV hypertrophy/ischaemia/dysfunction), the PHT is also shortened and the MVA may be overestimated. In patients with severe AR, LV pressure rises more rapidly in diastole, therefore the PHT will be shortened and the MVA will be overestimated. (EACVI Textbook of Echocardiography)

During the first 24-72 hours after percutaneous mitral valve commissurotomy there are abrupt changes in mitral gradient and LA compliance and the PHT method should be avoided. (EACVI Textbook of Echocardiography)

Thus this value is not valid in the presence of severe AR, or any conditions that significantly alter LA compliance and/or LV diastolic function, and in patients with degenerative, calcific MS. (Oxford Critical Care Echo)

Although the pressure half-time method is accurate when sinus rhythm is present, the increase in velocity due to atrial contraction may obscure the early-diastolic slope, particularly at high heart rates, so half-time measurements may not be possible unless a slow heart rate allows clear definition of the mid-diastolic slope. (Otto, Clinical Echocardiography 6e)

Pressure half-time is also prolonged with impaired LV relaxation and bradycardia, therefore underestimating MV area (and overestimating the apparent severity of mitral stenosis). (Practical Perioperative TOE)

In atrial fibrillation, several beats are averaged because mean gradient will vary with the RR interval. (Otto, Clinical Echocardiography 6e)

Overestimation of MS severity when there is associated MR (MR increases the mitral pressure gradient as it increases transmitral flow). (EACVI Textbook of Echocardiography)

Pressure gradients are influenced by both the MV area, as previously discussed, and the amount of blood flow across the valve, as an increase in flow will yield a higher gradient for a given valve area. (Essential Echocardiography)

Low cardiac output states and bradycardia may lead to low mean pressure gradient calculations in the presence of severe mitral stenosis. (Essential Echocardiography)

Where the CO is low and transvalvular velocities are correspondingly low; Where the CO is high, transmitral velocities may be high despite MS not being critical. (Oxford Critical Care Echo)

Remembering that the presence of significant stenosis of any valve will limit CO, and lead to underestimation of stenosis severity. (Oxford Critical Care Echo)

Thrombi are located preferentially in the LA appendage but also can occur in the body of the atrium as a protruding thrombus or as a laminated thrombus along the atrial wall or interatrial septum. LA thrombi are most common when atrial fibrillation is present but may occur even in sinus rhythm. (Otto, Clinical Echocardiography 6e)

TTE echo has a high specificity for the detection of an LA thrombus, but the sensitivity is less than 50%, so many are missed. (Otto, Clinical Echocardiography 6e)

TEE has a high sensitivity (about 99%) and specificity (about 99%) for the detection of an LA thrombus. (Otto, Clinical Echocardiography 6e)

The presence of LA SEC is a better predictor of LA thrombosis than LA size. Transoesophageal echocardiography (TOE) is recommended when the transthoracic approach is of poor quality, or to detect LA/LA appendage thrombosis before balloon mitral commissurotomy or following a thromboembolic event. Patients with MS commonly have decreased LA appendage emptying velocities. (EACVI Textbook of Echocardiography)

The assessment of LA volume instead of LA diameter is recommended because of the asymmetrical enlargement of the LA. (EACVI Textbook of Echocardiography)

Spontaneous echo contrast in the left atrium. This sign is strongly suggestive of significant mitral stenosis. (Practical Perioperative TOE)

Pulmonary pressures and resistance should be evaluated in all patients with mitral stenosis. (Otto, Clinical Echocardiography 6e)

When pulmonary hypertension is present, the RV is frequently dilated with reduced systolic function. Tricuspid regurgitation may be secondary to RV dysfunction and annular dilation, or may be caused by the rheumatic involvement of the tricuspid valve. (EACVI Textbook of Echocardiography)

PASP is estimated by summing (1) the pressure gradient between the pulmonary artery and right atrium, as derived from the modified Bernoulli equation, 4V2, where V is the tricuspid regurgitant jet velocity (assuming no pulmonary stenosis) and (2) the estimated right atrial pressure (RAP). In other words, PASP = 4V2 + RAP. (Essential Echocardiography)

Several additional echo findings support the diagnosis of significant MS, including the presence of LA dilatation and pulmonary hypertension; however, in rheumatic valve disease there may be significant LA dilatation in the absence of severe MS. Further, there is a wide range of pulmonary artery pressures for a given MVA. (Oxford Critical Care Echo)

Right-heart catheterization remains the only investigation enabling the measurement of pulmonary vascular resistance which may be useful in patients with severe pulmonary hypertension. (EACVI Textbook of Echocardiography)

With long-standing pulmonary hypertension, changes in the right ventricle may occur (e.g., hypertrophy, enlargement, decrement in function, and shifting of the interventricular septum toward the LV as right-sided pressures approach or exceed left-sided pressures). (Essential Echocardiography)

Associated MR is frequently seen in rheumatic MS. In rheumatic MR, the mechanism is the restricted leaflet motion, while after PMC, MR may result from leaflet or commissural tearing. Quantitation of MR severity is important as more than mild MR is a relative contraindication for PMC. (EACVI Textbook of Echocardiography)

A complete evaluation of the aortic valve is also important because the aortic valve is affected in approximately one-third of patients with MS. The severity of aortic stenosis may be underestimated due to reduced stroke volume in significant MS. (EACVI Textbook of Echocardiography)

In about 30% of patients with mitral stenosis, rheumatic disease also affects the aortic valve. (Otto, Clinical Echocardiography 6e)

Even in the absence of rheumatic involvement of the tricuspid valve, significant tricuspid regurgitation is common (due to pulmonary hypertension and annular dilation) in patients with mitral stenosis. Careful evaluation of tricuspid regurgitation severity is especially important preoperatively in case tricuspid annuloplasty is needed at the time of mitral valve surgery. (Otto, Clinical Echocardiography 6e)

When tricuspid valve dysfunction coexists, functional regurgitation is more common than tricuspid valve stenosis or organic, rheumatic tricuspid regurgitation. (EACVI Textbook of Echocardiography)

When MVA is less than 1.5 cm2, the decision to intervene is based on symptoms, suitability for PMC, SPAP values, and presence of AF. (EACVI Textbook of Echocardiography)

The European Society of Cardiology guidelines recommend (class IIa) percutaneous mitral valve commissurotomy (PMC) in patients with SPAP higher than 50 mmHg at rest. (EACVI Textbook of Echocardiography)

Echo Doppler is the standard clinical method for making the diagnosis and defining the stage of disease in patients with valvular mitral stenosis. Disease progression can be followed and the timing of intervention can be determined using Doppler echo and clinical data alone. Evaluation by cardiac catheterization rarely is needed. (Otto, Clinical Echocardiography 6e)

Significant mitral regurgitation is a contraindication to surgical or percutaneous commissurotomy. (Otto, Clinical Echocardiography 6e)

The mitral morphology score is low, and only mild mitral regurgitation is present, which indicates a high likelihood of immediate and long-term success with balloon mitral valvuloplasty. TEE is needed just before mitral valvuloplasty to evaluate for LA thrombus. (Otto, Clinical Echocardiography 6e)

Exercise testing is useful in MS to ascertain the level of physical conditioning and to elicit subtle cardiac symptoms. Exercise Doppler echocardiography is recommended when there is discrepancy between the resting echo findings and the severity of clinical symptoms. (EACVI Textbook of Echocardiography)

Useful parameters at stress echocardiography include exercise duration, blood pressure and heart rate response, change in mean mitral gradient, and increase in SPAP. Values of SPAP greater than 60-70 mmHg or mean mitral gradient greater than 15 mmHg at exercise echo are important findings for the management of these patients. (EACVI Textbook of Echocardiography)

A mean mitral gradient greater than 18 mmHg at dobutamine stress echo was reported to predict the occurrence of symptoms and the PMC intervention. Although dobutamine stress echo has prognostic value, it is less physiological than exercise echocardiography. (EACVI Textbook of Echocardiography)

Exercise testing to evaluate the change in pulmonary pressure from rest to exercise may be considered when symptoms are greater than expected for the degree of stenosis. Pulmonary pressures are calculated from the tricuspid regurgitant jet measured at rest and immediately after exercise. Rapid data acquisition after exercise is essential for an accurate estimation of the maximum exercise change. (Otto, Clinical Echocardiography 6e)

Mitral stenosis (MS) requiring ICU admission usually results from a precipitant (arrhythmia, pregnancy) causing haemodynamic deterioration in a patient with stable but significant stenosis, or may be a coincidental finding. (Oxford Critical Care Echo)

In mitral stenosis, prolonged diastolic filling can be impeded by tachycardia. (Practical Perioperative TOE)

Determining the importance of MS can be challenging in three situations, potentially relevant to the ICU setting: Where the CO is low and transvalvular velocities are correspondingly low; Where the CO is high, transmitral velocities may be high despite MS not being critical; Moderate degrees of MS may be a factor in potentiating poor gas exchange in patients with acute respiratory distress syndrome (ARDS) and should be evaluated carefully (especially in a high CO state). (Oxford Critical Care Echo)

TTE is usually adequate, and TOE should be reserved for when TTE images are inadequate, or to evaluate for LA thrombus. Cardiac catheterization is no longer recommended, unless echo is non-diagnostic or discordant with clinical data. (Oxford Critical Care Echo)

Severe mitral stenosis may be associated with a low stroke volume (due to the limitation of LV diastolic filling), resulting in a relatively low mean gradient. If volume flow rate increases, for example, with exercise, an increase in transmitral gradient is seen. (Otto, Clinical Echocardiography 6e)

Triage status: Mined the mitral stenosis chapters of Otto Clinical Echocardiography 6e (Ch 11), the EACVI Textbook (Ch 35), Practical Perioperative TOE (Ch 9), Oxford Critical Care Echo (Ch 14), and Essential Echocardiography (Maus/Tainter, Ch 13). All sources yielded usable verbatim excerpts and essentially all were assignable to specific Q&A documents; the few orphan excerpts below cover fluid-dynamics theory and continuity-equation detail that did not map cleanly to a single question. The BSE mitral guideline (ERP-20-0034) returned only a navigational/landing page with no extractable body text; the EAE/ASE valve stenosis recommendations page was not fetched (JS/paywalled), but its content is reflected in the EACVI and Oxford excerpts which cite it.

The fluid dynamics of a stenotic valve are characterized by the formation of a laminar, high-velocity jet in the narrowed orifice. (Otto, Clinical Echocardiography 6e)

The proximal velocity profile of an atrioventricular valve thus is hemielliptical, unlike the more flattened velocity profile proximal to a stenotic semilunar valve. (Otto, Clinical Echocardiography 6e)

The empiric relationship between MV area and deceleration time (or DT, in milliseconds) is MVA = 759/DT. (Practical Perioperative TOE)

When using the PISA method for estimating MV area for MV stenosis, an angle correction must be used when calculating the surface area of the PISA to allow for diastolic doming of the mitral leaflets. (Practical Perioperative TOE)

Treatment with PMC results in rapid recovery of LV systolic function through improvement in LV diastolic loading. This suggests that LV contractile properties in MS are modulated predominantly by LV diastolic filling rather than myocardial structural abnormalities. (EACVI Textbook of Echocardiography)