Echocardiographic assessment of Mitral regurgitation

• Detection • Assessment of severity• Etiology • Management strategy

• Detection-color doppler• Appearance of color doppler in LA in systole– postr motion of blood pool by MV closure– Reverberation from aortic flow– Normal pulmonary vein inflow

• Characteristics of true MR– Proximal flow acceleration– Ejection flow with a vena contracta– Downstream appearance-blood ejected through a

constraining orifice– Confined to systole– Doppler signals appropriate in color

• Jet of MR– Central or peripheral– Single or multiple

• Eccentric jet– Flail or partial flail of a leaflet-flow direction

opposite to involved leaflet– Ischemia-restriction of motion of one leaflet

Determination of severity

• CW doppler signal intensity• intensity of doppler signal proportional to number of

blood cells moving• weak signal-mild regurgitation

– Limitations• Affected by anatomic,physiological and technical

factors• Comparison with CWSI of antegrade flow

• Shape of regurgitant signal-V cut off sign• Mild MR-atrial pressure low and gradient remain high

throughout systole• Significant MR-atrial pressure increased in end systole

and gradient decreases• Produces a V shaped doppler signal

• Flow pattern in pulmonary vein• AP-4C view-PW placed in right upper pulmonary vein• Normal-systolic flow predominates• Moderate MR-loss of systolic flow with brief systolic

reversal• Severe MR –holosystolic flow reversal

• Pulmonary venous doppler-systolic VTI to diastolic VTI ratio to assess severity of MR

• >1-mild• 0.5 to 1-moderate• 0 to 0.5-moderately severe• <0-severe

• Limitations• AF-blunting of systolic component• Not detected if wall filters set too high• Absent in a dilated and compliant LA• False positive in eccentric jet directed to a vein

• Regurgitant jet area to left atrial area ratio• <15-mild• 15-30-moderate• 35-50-moerately severe• >50-severe

• Limitations• Doppler encoded size of jet overstates true volume of

flow from LV by amount of pre existing LA blood recruited into motion• Eccentric jet-smaller amount of recruitment and

underestimation of severity

• Low gain setting-underestimate severity• High gain-cluttering of image with noise and

difficult to identify true outline of regurgitant jet

• Non parallel alignment-lower frequency shifts

• Vena contracta• Narrowest portion of MR jet downstream from the orifice• Vena contracta width correlates with severity-<3mm

mild,>6mm severe• Remains accurate in acute regurgitation when jet area

may be misleading• Recommended approach

– perpendicular to jet direction– Narrow sector width– Zoom mode– Minimum depth

Calculation of regurgitant volumes and regurgitant fractions

• Stroke volume through all valves should be equal in absence of shunts or reg.

• Stroke volume through a reg.valve will be stroke volume plus reg.volume

• R vol= SV (MV) --- SV (LVOT)• RF=Reg.V/SV(MV)x100

• SV through LVOT• Annulus diameter

• PLAX view• Level of aortic annulus in systole• Inner edge to inner edge

• CSA=0.785xD²• VTI of LVOT from AP5C • LVOT SV=CSAxVTI• SV through MV –AP4C for annulus diameter and VTI

• Reg.volume=SV(mv)-SV (lvot)• Reg .fraction=RV÷SV(lvot)• Stroke volume of LV can also be calculated

from 2-D echo by simpson biplane method• ERO=RV/VTI(MR jet)

• Limitations – Equations based on steady flow through

cylindrical tube– Errors in diameter measurement-same phase as

VTI– Errors in VTI –Poor alignment,incorrect

placement,improper tracing– Intracardiac shunts– Presence of multivalvular lesions

• PISA method for calculation of ERO area• Acceleration of flow occurs proximal to regurgitant

orifice• A series of isovelocity surfaces leading to high velocity

jet in the orifice• Continuity principle-blood flow through a given

hemisphere must ultimately pass through the narrowed orifice

• AP4C view• Optimise color flow signal of regurgitant orifice• Decrease aliasing velocity by shifting color baseline• Aliasing limit noted• Radius measured from aliased region to MV• Reg.flow calculated• Max.MR velocity calculated

• ERO=MR flow/velocity of MR jet

Eccentric jet

• MVP-– Defined as systolic displacement of >2mm of one or

both mitral leaflets into the LA below the plane of mitral annulus

– Mitral leaflets often thickened >5mm or myxomatous

– MVP with thickening of leaflets prone for complications

– Prolapse with otherwise normal leaflets and no MR –low risk

MVP

• Rheumatic MR-commissural fusion,chordal fusion and shortening

• Infective endocarditis-leaflet destruction,perforation or deformity

• Marfan syn.-long redundant antr.leaflet,aortic pathology• Ischemic MR-restricted leaflet motion• Papillary muscle rupture-a/c MI• Functional MR-annular dilatation• Mitral annular calcification-impair systolic contraction

leading to MR

• LV dilatation• LA dilatation• Decline in LV contractility• PA pressure from TR jet

Thank you