ECHOCARDIOGRAPHY IN MITRAL STENOSIS

ECHOCARDIOGRAPHY IN MITRAL STENOSIS
Dr RAJESH K F

CAUSES AND ANATOMIC PRESENTATION
Rheumatic Commissural fusion Leaflet thickening Chordal shortening and fusion Superimposed calcification Degenerative MS Annular calcification Rarely leaflet thickening and calcification at base

Congenital MS Subvalvular apparatus abnormalities Inflammatory-SLE Infiltrative Carcinoid heart disease Drug induced valve disease Leaflet thickening and restriction Rarely commissural fusion

2D ECHO Commissural fusion PSAX echo scanning of valve
Important in distinguishing degenerative from rheumatic valve Complete fusion indicate severe MS Narrow diastolic opening of valve leaflets

Restricted mobility -PLAX
Early diastolic doming motion of the AML- restriction of tip motion

Leaflet thickening -PLAX

Chordal thickening, shortening and fusion –PLAX and A4C

Superimposed calcification

Dilated LA LA and LA appendage thrombus Paradoxical septal motion Dilated RV and RA

Wilkins score -Mitral valve score <8 are excellent candidates for BMV

Limitations of wilkin score
Assessment of commissural involvement is not included Limited in ability to differentiate nodular fibrosis from calcification. Doesn’t account for uneven distribution of pathologic abnormalities. Frequent underestimation of subvalvular disease. Doesn’t use results from TEE or 3D echo

Cormier’s method

3D ECHO TEE and TTE Higher accuracy than 2D echo
Detailed information of commissural fusion and subvalvular involvement MVA measurement in calcified and irregular valve MVA measurement after BMV Restenosis after commissurotomy commissural refusion valve rigidity with persistent commissural opening

From LA From LV

RT3DE score of MS severity

Total RT3DE score ranging from 0 to 31 points
Total score of mild MV involvement was defined as <8 points Moderate MV involvement 8–13 Severe MV involvement >14

M MODE ECHO Decreased E-F Slope >80 mm/s MVA=4-6cm²
Thickened Mitral Leaflets Anterior Motion or Immobility of Posterior Mitral Leaflet-tethering at tips Diastolic Posterior Motion of Ventricular Septum (severity of stenosis)

TEE For diagnosis and quantification little yield
Spontaneous echo contrast LA and LA appendage thrombus Use of transgastric plane for evaluation of chordal structures Assessment of commissural calcification and fusion to predict procedural outcome after BMV

Commissure score NON CALCIFIED FUSION ANTEROLATERAL COMMISSURE
POSTEROMEDIAL COMMISSURE ABSENT PARTIAL 1 EXTENSIVE 2 TOTAL SCORE O TO 4

Scores for anterolateral and posteromedial commissures were combined such that each valve had an overall commissure score ranging from 0–4 A high score indicated extensively fused, non‐calcified commissures that were therefore more likely to split A low score indicated either minimal fusion or the presence of resistant commissural calcification

ASSESSMENT OF MS SEVERITY
2D OR 3D ECHO MVA BY PLANIMETRY DOPPLER PRESSURE GRADIENTS MVA BY PHT CONTINUITY EQATION PISA MITRAL VALVE RESISTANCE PASP

MVA BY PLANIMETRY 2D Echo Best correlation with anatomical area
Scanning method to avoid overestimation measured at leaflet tips in a plane perpendicular to mitral orifice Elliptical in shape Direct measure of mitral orifice including opened commissures in PSAX

Excessive gain setting may underestimate valve area
Zoom mode is better for delineation Harmonic imaging can improve planimetry measurement Optimal time is mid diastole obtained by cine loop mode on a frozen image Multiple measurements in AF or incomplete commissural fusion difficult in calcified valve,chest deformity and previous commissurotomy

Real time 3D echocardiography
identify true smallest orifice independent of its orientation most accurate ultrasound technique for measuring MVA, with a superior pre- and postprocedural agreement with the Gorlin’s derived MVA Less experience dependent and more reproducible

Mitral leaflet separation (MLS) index
Distance between the tips of the mitral leaflets in parasternal long-axis and four-chamber views it can be used as a semiquantitative method for the assessment of MS severity A value of 1.2 cm or more provided a good specificity and PPV for the diagnosis of non severe MS less than 0.8 cm -severe MS. It is not accurate in patients with heavy mitral valvular calcification and post BMV

PRESSURE GRADIENT Apical window
CWD /PWD at or after tip of mitral valve Maximal and mean gradient Bernoulli equation( P =4V2) Derived from transmitral velocity flow curve Heart rate to be mentioned CD to identify eccentric mitral jet

Maximal gradient influenced by LA compliance and LV diastolic function
In AF average of 5 cycles with least variation of R-R interval and as close possible to normal HR MVG dependent on HR,COP and associated MR Tachycardia, increased COP and associated MR overestimates gradient Maximal gradient is markedly affected

PRESSURE HALF TIME T1/2 is time interval in msecs between max mitral gradient in early diastole and time point where gradient is half max gradient Or it is the time when velocity falls to 1/1.414 peak PHT related to decceleration time PHT =.29x DT MVA=220/PHT

The empirically determined constant of 220 is proportional to the product of net compliance of left atrium and LV, and the square root of maximum transmitral gradient in a model that does not take into account active relaxation of LV

Obtained by tracing deceleration slope of E wave on Doppler spectral display
Concave not feasible If slope is bimodal deceleration slope in mid diastole rather than early diastole is traced

AF avoid short cycles and average different cardiac cycles

Less dependent on COP or coexistent MR
Useful when mean transmitral gradient is misleading MR -transmitral gradient overesimated Low COP –mean transmitral gradient -underestimated

MS MS+MR MR

Factors that may affect PHT by influencing LA pressure decline
More rapid LA pressure decline shorten PHT LA draining to second chamber –ASD LA pressure drop rapidly PHT shortened Stiff LA –low LA compliance

Factors affect PHT by influencing LV pressure rise
More rapid LV pressure rise shorten PHT If LV fills from a second source PHT –AR LV pressure rise more rapidly PHT will be shortened If LV is stiff-low ventricular compliance LV pressure may rise more rapidly

All factors affect PHT (ASD, AR, low LA or LV compliance )
shorten PHT Leads to overestimation of MVA Therefore PHT never under estimate MVA Therefore if PHT >220 MS is severe If PHT is < 220 consider other methods to assess severity

Prosthetic MVA Not been validated Affected mainly by DD More accurate method is continuity equation

Not reliable After BMV Normally LA and LV compliance counteract each other when gradient and compliance are subject to important and abrupt changes alter relation between PHT and MVA Upto 48 hrs post BMV

CONTINUITY EQATION LVOT AREA

MVA X VTI mitral= LVOT area X VTI aortic
MVA = LVOT area X VTI aortic VTI mitral MVA= p D X VTI aortic VTI mitral D is diameter of LVOT in CM and VTI in CM SV can be estimated from PA Method not useful in AF,AR or MR Useful in degenerative calcific MS

PISA Based on hemispherical shape of convergence of diastolic mitral flow on atrial side of mitral valve and flow acceleration blood towards mitral valve

MVA x MV = PISA x AV MVA = PISA x AV MV PISA = 2pr2 x a 180 MVA = 2pr2 x AV x a MV 180

Zoom on the flow convergence
Upshift the baseline velocity and use an aliasing velocity of 20–30 cm/s Measure the radius of the flow convergence region and the transmitral velocity at the same time in early diastole Measure the α angle formed by the mitral leaflets Use of a fixed angle value of 100° can provide an accurate MVA estimation in patients with MS.

Can be used in presence of significant MR, AR, differing heart rhythms
Not affected by LA,LV compliance Multiple measurements required M mode improves accuracy

Colour M-mode PISA Instantaneous measurement of MVA throughout diastole Under guidance of magnified 2D colour imaging, colour M-mode tracings were recorded by placing the M-mode cursor line through the centre of the flow convergence. Diastole was divided into four phases of equal duration: early, mid, mid-late, and late diastole. Peak radius of flow convergence was measured during each phase to calculate mitral flow rate

Each radius was measured from the red–blue aliasing level to the tip of the leaflet at the orifice
Colour M-mode analysis was then paired with continuous wave Doppler Three to five measurements of each variable (on matched cycle for colour M-mode and Doppler methods) were averaged, depending on the patient's rhythm. MVA was then calculated separately for each phase of diastole

MITRAL VALVE RESISTANCE
MVR=Mean mitral gradient/ transmitral diastolic flow rate Transmitral diastolic flow rate= SV/DFP It correlate well with pulmonary artery pressure

PASP CWD Estimation of the systolic gradient between RV and RA
Multiple acoustic windows to optimize intercept angle Estimation of RAP according to IVC diameter

STRESS ECHOCARDIOGRAPHY
Useful to unmask symptoms in patients with MVA<1.5cm2 and no or doubtful complaints Discrepancy between resting doppler and clinical findings Semi-supine echocardiography exercise (30 to 60 secs of leg lifts) is now preferred to post exercise echocardiography Allows monitoring gradient and pulmonary pressure in each step of increasing workload

Mean mitral gradient and PASP to be assessed during exercise
Mean gradient >15 mmhg with exercise is considered severe MS A PASP > 60 mmHg on exercise has been proposed as an indication for BMV Dobutamine stress echo mean gradient >18 mmhg with exercise is considered severe MS

Associated lesions Quantitation of LAE Associated MR and its mechanism
Severity AS (underestimated) AR- t1/2 method to assess MS is not valid TR ,tricuspid annulus Secondary pulmonary HTN-TR

GRADING OF SEVERITY OF MS
MILD MODERATE SEVERE SPECIFIC VALVE AREA(cm2) >1.5 1-1.5 <1 NONSPECIFIC MEAN GRADIENT (mmHg) <5 5-10 >10 PASP (mmHg) <30 30-50 >50

THANK U

1 Pressure half time in MS affected by all except
A ASD B MR C AR D HOCM

2 In case of a pure MS transmitral mean gradient is mmhg and mitral area by planimetry is 1.1cm2 it is graded as A severe B moderate C mild D indeterminate

3 Commissural fusion is not a feature of MS in
A RHD B Calcific MS C SLE D Carcinoid disease

4 Not included in Wilkins score is
A commissural fusion B restricted mobility C leafllet thickening D subvalvular fusion

5 harmonic imaging useful in
A 2D MVA B PHT C PISA D M mode

6 mitral leaflet separation index less than ----cms indicate severe MS
B 0.6 C 0.8 D 0.2

7 continuity equation useful in MVA calculation in
A AF B AR C MR D Calcific MS

8 Mean gradient greater than ---- mmhg with exercise echocardiography is considered severe MS
B 12 C 15 D 18

9 In a case of severe AR with MS mitralPHT obtained is 280 severity of MS is
A mild B moderate C severe D none of the above

10 Method to assess severity of MS in diastolic dysfunction is
A PHT B PISA C continuity equation D mitral valve resistance