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 moderate 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- 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

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