Journal of the Saudi Heart Association (2011) 23, 51–58

King Saud University

Journal of the Saudi Heart Association

www.ksu.edu.sawww.sha.org.sa

www.sciencedirect.com

MINI REVIEW – CONTINUING MEDICAL EDUCATION

Echocardiography in mitral stenosis

A.S. Omran, Ahmed A. Arifi *, A.A. Mohamed

Department of Cardiac Sciences, King Abdulaziz Cardiac Center, National Guard Health Affairs, Saudi Arabia

Received 18 July 2010; accepted 18 July 2010Available online 7 September 2010

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KEYWORDS

Echocardiography;

Mitral stenosis;

3D echocardiography

Corresponding author. Ad

ail Code 1413, P.O. Box 224

-mail address: arifiahmed@

16-7315 ª 2010 King Saud

sevier B.V. All rights reserve

er review under responsibilit

i:10.1016/j.jsha.2010.07.007

Production and h

dress: Ki

90, Riyad

hotmail.c

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osting by E

Abstract Echocardiography plays a major role in diagnosis, etiology and severity of Mitral Steno-

sis (MS), analysis of valve anatomy and decision-making for intervention. This technique has also a

crucial role to assess consequences of MS and follow up of patients after medical or surgical inter-

vention. In this article we review the role of conventional echocardiography in assessment of mitral

stenosis and future direction of this modality using 3D echocardiography.ª 2010 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.

1. Introduction

In normal cardiac physiology, the mitral valve opens duringleft ventricular diastole, to allow blood to flow from the left at-

rium to the left ventricle. This flow direction will be maintainedas long as the pressure in the left ventricle is lower than thepressure in the left atrium and the blood flows down the pres-sure gradient.

Mitral stenosis (MS) is a mechanical obstruction in bloodflow from the left atrium to the left ventricle. Obstruction hap-pens due to thickening and immobility of the leaflets, thickening

and fusionof the chorda tendinae ormitral annular and commis-sural calcification. The normal area of the mitral valve orifice is

ng Abdulziz Cardiac Center,

h 11426, Saudi Arabia.

om (A.A. Arifi).

y. Production and hosting by

Saud University.

lsevier

about 4–6 cm2 when the mitral valve area goes below 2 cm2, the

valve causes an impediment to the flowof blood into the left ven-tricle, creating a pressure gradient across the mitral valve. Thisgradient may increase by the rise in heart rate or cardiac output.When themitral valve area becomes less than 1 cm2, therewill be

an increase in the left atrial pressure to overcome the valve gra-dient. This rise in the left atrial pressure is then transmitted to thepulmonary vasculature and causes pulmonary hypertension and

eventually pulmonary congestion and edema.Mitral stenosis consists of 12% of all valvular heart disease

in Euro Heart Survey. Etiology of MS in adult patients in the

great majority of cases (more than 90%) is the rheumaticinvolvement of the mitral valve. Other etiologies such as infec-tive endocarditis, mitral annular calcification in elderly pa-tients, congenital malformation (parachute mitral valve),

systemic lupus erythematosis, carcinoid heart disease, endo-myocardial fibrosis and rheumatoid arteritis are representingless than 10% of adult cases.

2. Diagnosis of MS-

2.1. Transthoracic 2D – echocardiography

Mitral valve assessment with echocardiography should includethe pattern of valve involvement and calcification, severity of

52 A.S. Omran et al.

stenosis, associated mitral regurgitation and other co-existent

valve lesions and atrial chamber dilatation and function. Mi-tral stenosis can be assessed in parasternal, apical or subcostalviews. As with any stenotic valve the main diagnostic feature inthe parasternal long axis view (Fig. 1) as in rheumatic MS, the

anterior mitral leaflet (AMVL) shows diastolic doming orhockey-stick shape. And the posterior mitral leaflet (PMVL)has restricted motion or is totally immobile. This doming is

due to the reduced mobility of the valve tips compared tothe base of the leaflets.

Echocardiography can also adequately assess the Subvalvu-

lar apparatus changes such as thickening, shortening, fusion ofchordal and calcification (Fig. 1). Color Doppler in this viewwith diastolic turbulence across the mitral valve confirms the

diagnosis. On the other hand, Parasternal short axis view ofthe mitral valve is used to assess the leaflets thickening and

AMVL

LV

PMVL

Figure 1 Parasternal long axis view in diastole, showing diastolic do

and thickened, restricted posterior mitral valve leaflet (PMVL). RV =

Figure 2 Parasternal short axis view of the mitral valve at the level o

Prior to percutaneous balloon mitral valvuloplasty (PBMV), showing

after PBMV, showing complete opening of the anterolateral comm

MVA= 2.0 cm2.

fusion of commissures. The parasternal short axis view is also

used to assess the mitral valve orifice area by planimetry of themitral leaflets at the level of tips (Fig. 2).

3. Indices of stenosis severity

The Following are different means of measurements by echo-cardiography to assess the severity of MS, which are manda-

tory in all patients:Planimetry of mitral valve at the level of the leaflets tips in

parasternal short axis view (Fig. 2). This method is a very

familiar technique by 2D echocardiography but the samemethod can also be used in 3D echocardiography en-face viewof mitral valve (Fig. 9). However, newly developed QLAB soft-

ware in 3D echo is now available for calculation of mitral valveorifice area which requires further validation (Fig. 10).

LA

ming (hockey-stick shape) of anterior mitral valve leaflet (AMVL)

right ventricle, LV = left ventricle, LA = left atrium.

f the tips to measure mitral valve area (MVA) by planimetry. (A)

fused both commissures with MVA = 1.2 cm2. (B) Same patient

issure and partial opening of the posteromedial commissure.

Echocardiography in mitral stenosis 53

Calculation of mitral valve area (MVA) by pressure half-time

(P1/2 t) should be done in an apical four chamber view usingcontinuous wave Doppler (Fig. 3). Pressure half-time methodis not valid immediately after percutaneous balloon mitral

Figure 3 Calculation of the mitral valve area (MV

Figure 4 Continuous wave Doppler parallel to the mitral inflow in a

across the mitral valve. Measurements should be done in 3–5 consecu

valvuloplasty (PBMV). MVA should be averaged in 3 consec-

utive beats and in case of atrial fibrillation in it should 5 beats.Mean pressure gradient across the mitral valve can be mea-

sured in apical views. Modal Doppler (most dense portion of

A) by the method of pressure half-time (P1/2 t).

pical 4 chamber view to measure mean peak gradient (Mean PG)

tive beats and averaged.

Figure 5 (A) Estimation of pulmonary artery systolic pressure (right ventricular systolic pressure) using TR velocity and gradient in

short axis view in a patient with severe MS and severe pulmonary hypertension (B) Calculation of left atrial volume using method of discs

(MOD) in apical 4 chamber view in same patient, showing severe increase of LA volume.

Table 1 EAE/ASE recommendations for classification of mitral stenosis severity.

Mild Moderate Severe

Specific findings

valve area (cm2) >1.5 1.0–1.5 <1.0

Supportive findings

Mean gradient (mmHg)a <5 5–10 >10

Pulmonary artery pressure (mmHg) <30 30–50 >50

a At heart rates between 60 and 80 bpm and in sinus rhythm.

Table 2 Assessment of mitral valve anatomy according to the Wilkins score (Boston score).

Grade Mobility Thickening Calcification Subvalvular thickening

1 Highly mobile valve

with only leaflet tips

restricted

Leaflets near normal in

thickness (4–5 mm)

A single area of

increased echo

brightness

Minimal thickening just below the

mitral leaflets

2 Leaflet mid and base Midleaflets normal,

considerable

thickening of margins

(5–8 mm)

Scattered areas of

brightness confined

to leaflet margins

Thickening of chordal structures

extending to one-third of the

chordal length

3 Valve continues to

move forward in

diastole, mainly

from the base

Thickening extending

through the entire

leaflet (5–8 mm)

Brightness extending

into the mid-

portions of the

leaflets

Thickening extended to distal third

of the chords

4 No or minimal

forward movement

of the leaflets in

diastole

Considerable

thickening of all leaflet

tissue (>8–10 mm)

Extensive brightness

throughout much of

the leaflet tissue

Extensive thickening and

shortening of all chordal structures

extending down to the papillary

muscles

54 A.S. Omran et al.

the Doppler curve) should be used for calculation (Fig. 4). Thegradient can be measured by tracing the dense outline of mitraldiastolic inflow and the mean pressure gradient is automati-cally calculated. The severity can be assessed as mild (<5),

moderate (5–10) and severe (>10).

Estimation of pulmonary artery systolic pressure and the

right ventricular systolic pressure (RVSP) is necessary. It canbe measured from tricuspid regurgitation velocity by Bernoulliequation (Fig. 5). RVSP can also be assessed during exercise in

borderline cases.

Table 3 Assessment of mitral valve anatomy according to the

Cormier score.

Echocardiographic

group

Mitral valve anatomy

Group 1 Pliable non-calcified anterior mitral leaflet

and mild subvalvular disease (i.e. thin chordae

>10 mm long)

Group 2 Pliable non-calcified anterior mitral leaflet

and severe subvalvular disease (i.e. thickened

chordae <10 mm long)

Group 3 Calcification of mitral valve of any extent, as

assessed by fluoroscopy, whatever the state of

subvalvular apparatus

PMVL AMVL

Subvalvular thickening

Figure 6 TEE long axis view of a patient with severe mitral

stenosis, diastolic doming and hockey-stick shape of the anterior

mitral valve leaflet (AMVL) and restricted posterior leaflet

Echocardiography in mitral stenosis 55

Consequences of mitral stenosis on other cardiac chamberssuch as left atrial dilatation, tricuspid regurgitation and alsoright ventricular function should be evaluated by echocardiog-raphy. Left ventricular function is usually intact in uncompli-

cated mitral stenosis.

(PMVL). Subvalvular apparatus is thickened but is not calcified.

Wilkins score of this valve is calculated about 8, indicating

suitability for PBMV.

4. Grading of mitral stenosis

In grading the severity of MS based on echocardiographicevaluation, the following recommendations by the EAE/ASE

(Baumgartber et al., 2009) are the used standards of practice.Please refer to Table 1.

5. Percutaneous balloon mitral valvuloplasty (PBMV)

Percutaneous valvuloplasty was introduced by Inoue in 1984

and revolutionized the treatment of selected patients withMS. Suitability of mitral valve for PBMV is based on echo-cardiographic findings. Wilkins score (Wilkins et al., 1988 –Table 2) and Cormier score (Lung et al., 1996 – Table 3)

are the most widely accepted criteria for pre-procedureselections. Transesophageal echocardiography (TEE) is agreat tool to assess anatomy and morphology of mitral

Ca++

LV

A

Figure 7 Extensive calcification of mitral annulus and leaflets in a

calcification on the leaflets and annulus extending to the base of left at

same patient, confirming these calcifications shown as bright echo den

valve leaflets, commissures, chorda and subvalvular appara-tus (Figs. 6 and 7). Pre-op TEE is mandatory to rule outleft atrial clot prior to PBMV (Fig. 8). In short, the follow-ing are the factors which favor a successful PBMV; Thick-

ening confined to valve tips, good mobility of anteriormitral valve leaflet, little chordal involvement, no more than++mitral regurgitation, no left atrial thrombus and no

commissural calcification.

6. 3D echocardiography

3D echocardiography, especially 3D TEE is a merging tooland is very promising to assess anatomy of mitral valve

due to excellent location of mitral valve in relation with

Extensive calcification

B

LAA

patient with severe rheumatic MS. (A) 2-D TEE view showing

rial appendage (LAA). (B) 3-D TEE, zoom-mode, surgical view of

sities.

LA

LAA

ClotSmoke

LV

Figure 8 Pre-op TEE assessment done for a patient with severe MS, prior to percutaneous balloon mitral valvuloplasty (PBMV),

showing severe smoke in left atrium (LA) and large clot in left atrial appendage (LAA). PBMV was canceled and medical treatment

started.

A B

PMVL

AMVL Grid= 5 mm

PMCALC

Figure 9 3D TEE zoom-mode of mitral valve with severe rheumatic MS. (A) Left atrial (LA) view or surgical orientation, as surgeon

will see the mitral valve in the operating room after opening the left atrium. Aorta is located anterior to the MV and left atrial

appendage is oriented at the left side of surgeon. (B) LV view of mitral valve showing fish mouth of mitral orifice. Surgeon will not see

this side of mitral valve except opening from aortic root. Note grid in the screen which can be used for measurements but still should be

validated.

56 A.S. Omran et al.

esophagus. 3D TEE can show en-face view of the mitralvalve from left atrial and left ventricular side. Morphologyof the mitral valve, degree of fusion of the commissures,area of mitral valve by QLAB software, result of the bal-

loon valvuloplasty and mechanism of possible post balloon

mitral regurgitation are the information which can be dri-ven from 3D TEE (Figs. 9–12). This technique can be usedin Catheterization Laboratory during PBMV and in theoperation room during surgical correction of mitral

stenosis.

Figure 10 Calculation of mitral valve area (MVA) by QLAB software implemented in the 3D echo machine. (A) Two orthogonal views

of mitral valve are derived from a 3D zoom-mode acquisition of the mitral valve. After proper alignment of lines representing x, y and z

axis, mitral valve orifice will appear and MVA can be traced. (B) MVA was traced in same patient of Fig. 9 and showed 1.1 cm2. This

software still needs validation.

Figure 11 3D TEE zoom-mode acquisition of a patient with severe rheumatic mitral stenosis, viewing from LV side. (A) Prior to balloon

valvuloplasty, mitral valve area (MVA) calculated by the grid and 3D QLAB was 0.7–0.8 cm2. (B) Same view, 2 days after successful

PBMV, both commissures are fully split. MVA calculated by same methods showed increasing to 2.1 cm2.

BA

ALC PMC

AvulsionMR

Figure 12 3D TEE, full volume color acquisition of mitral valve of patient with history of severe mitral stenosis who underwent balloon

valvuloplasty one year ago and now presented with severe mitral regurgitation. (A) Full volume acquisition of mitral with color

suppressed, showing over-spliting of both commissures . Anterolateral commissure (ALC) showed line of avulsion of this commissure

towards A1 segment of anterior mitral leaflet. (B) Same view with color showed severe mitral regurgitation (MR) jet origination mostly

from that avulsion and second jet from over-spliting posteromedial commissure (PMC).

Echocardiography in mitral stenosis 57

58 A.S. Omran et al.

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