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Mitral Stenosis Meghan York September 23, 2009. Outline: Mitral Stenosis I. Normal Mitral Valve Anatomy II. Etiology and Epidemiology III. Echocardiography.

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Presentation on theme: "Mitral Stenosis Meghan York September 23, 2009. Outline: Mitral Stenosis I. Normal Mitral Valve Anatomy II. Etiology and Epidemiology III. Echocardiography."— Presentation transcript:

1 Mitral Stenosis Meghan York September 23, 2009

2 Outline: Mitral Stenosis I. Normal Mitral Valve Anatomy II. Etiology and Epidemiology III. Echocardiography Evaluation IV. Physiologic Disturbances V. Treatment Options

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4 Mitral Valve Anatomy Posterior leaflet encircles majority of annulus Posterior leaflet encircles majority of annulus Anterior leaflet is longer across diameter of valve Anterior leaflet is longer across diameter of valve

5 Mitral Valve Orifice Area Normal 4 – 6 cm2 Mild Stenosis 1.6 – 2.5 cm2 Moderate Stenosis 1.0 – 1.5 cm2 Severe Stenosis < 1.0 cm2

6 Etiology Rheumatic Fever (majority of cases of mitral stenosis) Rheumatic Fever (majority of cases of mitral stenosis) Calcific Mitral Stenosis Calcific Mitral Stenosis Congenital Congenital Endocarditis with large vegetation causing obstruction Endocarditis with large vegetation causing obstruction

7 Etiology (continued) Anoretic drugs Anoretic drugs Carcinoid Carcinoid Systemic Lupus Systemic Lupus Rhuematoid Arthritis Rhuematoid Arthritis Mucopolysaccharidoses Mucopolysaccharidoses Whipple’s Disease Whipple’s Disease Amyloid deposition Amyloid deposition

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10 Epidemiology: Rheumatic Mitral Stenosis Leading cause of congestive heart failure in developing countries Leading cause of congestive heart failure in developing countries Without surgical intervention, mitral stenosis results in 85% mortality 20 years after onset of symptoms Without surgical intervention, mitral stenosis results in 85% mortality 20 years after onset of symptoms 2/3 of all cases are in women 2/3 of all cases are in women Age of onset of symptoms usually age 20 – 40 Age of onset of symptoms usually age 20 – 40 50% of patients with symptomatic MS have history of acute rheumatic fever 20 yrs prior 50% of patients with symptomatic MS have history of acute rheumatic fever 20 yrs prior

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12 Echocardiographic Evaluation A) Valve anatomy, mobility, calcification B) Assessment of severity: 1)Mitral valve area - continuity equation method and PISA - planimetry - pressure half time method 2)Transmitral pressure gradient (Bernoulli) 3)Sequelae (pulmonary hypertension, left atrial dilation, left atrial thrombus)

13 Valve anatomy, mobility, calcification

14 Rheumatic Mitral Stenosis Medial and lateral commissural fusion Medial and lateral commissural fusion Thickening of leaflet tips Thickening of leaflet tips Hockey stick appearance of leaflets Hockey stick appearance of leaflets Doming of leaflets Doming of leaflets Chordae Chordae Fibrosis Fibrosis Shortening Shortening Fusion Fusion Calcification Calcification

15 Hockey stick appearance of anterior leaflet

16 Doming of leaflets in diastole

17 Chordal involvement

18 Calcific Mitral Stenosis Mitral Annular Calcification occurs at annulus adjacent to posterior leaflet Mitral Annular Calcification occurs at annulus adjacent to posterior leaflet Calcification extends from annulus to base of leaflet Calcification extends from annulus to base of leaflet Leaflet tips remain thin and flexible Leaflet tips remain thin and flexible

19 Use of 3D Echocardiography Can be transthoracic or transesophageal Can be transthoracic or transesophageal Improves determination of involvement of chordal structures Improves determination of involvement of chordal structures Further characterizes fibrosis and calcification of leaflets Further characterizes fibrosis and calcification of leaflets

20 3D Echocardiography

21 Fish Mouth Appearance

22 M-Mode Increased echogenicity of leaflets Increased echogenicity of leaflets Decreased excursion and reduced separation of anterior and posterior leaflets Decreased excursion and reduced separation of anterior and posterior leaflets Reduced diastolic E-F slope of mitral closure Reduced diastolic E-F slope of mitral closure Paradoxical anterior diastolic motion of posterior mitral leaflet (due to tethering of posterior leaflet to anterior leaflet in rheumatic MS) Paradoxical anterior diastolic motion of posterior mitral leaflet (due to tethering of posterior leaflet to anterior leaflet in rheumatic MS)

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24 Increased EPSS Normal Severe

25 E Point Septal Separation Reduced diastolic E – F slope of closure

26 Diastolic Anterior Motion of Posterior Leaflet NormalMitral Stenosis

27 Assessment of Severity Mitral valve area 1) Continuity equation 2) PISA 3) Planimetry 4) Pressure half time Transmitral Pressure Gradient 1)Bernoulli’s equation

28 Continuity Equation Cross sectional area of the mitral valve multiplied by velocity time integral of mitral stenosis jet = Cross sectional area of LVOT(or PA) multiplied by velocity time integral of LVOT (or PA) Therefore: CSA(mitral)= stroke volume/VTI(mitral)

29 Proximal Isovelocity Surface area: PISA Used for calculating continuity equation in setting of mitral regurgitation Used for calculating continuity equation in setting of mitral regurgitation Blood flow increases as nears the stenotic orifice Blood flow increases as nears the stenotic orifice Color doppler flow parameters are adjusted to demonstrate well defined hemispherical aliasing surface are on the atrial side of the mitral orifice Color doppler flow parameters are adjusted to demonstrate well defined hemispherical aliasing surface are on the atrial side of the mitral orifice Velocity equals Nyquist limit Velocity equals Nyquist limit CSA(mitral)=2 π r 2 x velocity aliasing /velocity pk transmitral

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31 Planimetry 2D short axis imaging of mitral valve during diastole allows direct planimetry of valve area 2D short axis imaging of mitral valve during diastole allows direct planimetry of valve area Mitral valve is a planar elliptical orifice that is constant in mid diastole Mitral valve is a planar elliptical orifice that is constant in mid diastole Planimetry should be done at the narrowest cross sectional area at the leaflet tips Planimetry should be done at the narrowest cross sectional area at the leaflet tips Consider starting at apex and slowly scanning up to find most distal point of leaflets (mitral valve shaped like a funnel during diastole) Consider starting at apex and slowly scanning up to find most distal point of leaflets (mitral valve shaped like a funnel during diastole) Accuracy of measurement has been validated by comparison to post surgical specimens Accuracy of measurement has been validated by comparison to post surgical specimens

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33 Pressure Half Time Principle: rate of pressure decline across stenotic orifice is determined by CSA of the orifice Principle: rate of pressure decline across stenotic orifice is determined by CSA of the orifice Influence of LA & LV compliance assumed to be negligible Influence of LA & LV compliance assumed to be negligible Obtain doppler images of mitral inflow Obtain doppler images of mitral inflow Pressure half time = time from V max to V max /√2 Pressure half time = time from V max to V max /√2 Mitral valve area = 220/ pressure half time Mitral valve area = 220/ pressure half time

34 220 t½ t½ MVA =

35 Transmitral Pressure Gradient Peak Diastolic Pressure gradient = 4(orifice velocity) 2 Mean Diastolic Pressure gradient = 4 (v v v v n 2 )/ n Where v x is an instantaneous velocity Mitral valve area of 1 cm 2 typically requires transmitral gradient of 20 mmHg to maintain normal cardiac output at rest. However, severe mitral stenosis can present with a resting gradient ranging from 5 – 30 mm Hg.

36 Obstruction of trans-mitral blood flow Increased flow velocity Increased pressure gradient across valve Left atrial dilation Pulmonary hypertension Pulmonary Edema Right sided heart failure Decreased LV filling Decreased stroke volume

37 Treatment of Mitral Stenosis Treatment of congestive heart failure Treatment of congestive heart failure Diuretics Diuretics Beta blockers Beta blockers Treatment and stroke prophylaxis if atrial fibrillation present Treatment and stroke prophylaxis if atrial fibrillation present Percutaneous transvenous mitral valvuloplasty Percutaneous transvenous mitral valvuloplasty Surgical open mitral commisurotomy Surgical open mitral commisurotomy Mitral valve replacement Mitral valve replacement

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39 Patient Selection for Valvuloplasty 1)Severity of symptoms and physiologic changes - resting and stress echo 2)Risk of procedural complications -resting echo

40 Wilkins Score: Assessment of Mitral Valve Morphology

41 Selection for Valvuloplasty Score < 8: probably valvuloplasty unless: Score < 8: probably valvuloplasty unless: > 2+ mitral regurgitation > 2+ mitral regurgitation previous surgical commissurotomy previous surgical commissurotomy Score 9-11: possible valvuloplasty if: Score 9-11: possible valvuloplasty if: No mitral regurgitation No mitral regurgitation Age < 45 Age < 45 Score 12-14: surgical commissurotomy Score 12-14: surgical commissurotomy May consider as palliative procedure May consider as palliative procedure Palacios et al. Circulation. 2002

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44 Stasis of blood flow and thrombus formation

45 Thank you!

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