Table 3.

Mechanisms and jet direction.

Mechanism of central jets

– Annular dilation and reduced leaflet coaptation through LA enlargement, most often caused by atrial fibrillation. Usually associated with reduced coaptation height and leaflet flattening in systole. – Central jets are also seen when LV dilation leads to symmetric leaflet tethering and increased coaptation height.

Mechanism of posteriorly directed jets

– Anterior leaflet prolapse and or flail causes simple override of the anterior leaflet directing the regurgitant jet in the opposite direction. – Ischaemic MR occurs when papillary muscle dysfunction leads to tethering of the posterior leaflet. This inhibits the posterior leaflet from returning to a normal systolic closure position and results in the anterior leaflet coapting with the body of the posterior leaflet rather than the tip. This creates a mechanism of pseudo-prolapse that directs the jet in the direction of the lesion, in this case posteriorly. – Systolic distortion of the leaflets secondary to the systolic anterior motion of the AMVL.

Anteriorly directed jet

– Posterior leaflet prolapse and or flail causes simple override of the anterior leaflet directing the regurgitant jet in the opposite direction.

Leaflet perforation

– The direction of MR jets due to leaflet perforation depends upon the site of the regurgitant orifice. – The anterior leaflet base is the most common site of iatrogenic perforation. Assessment post-MV repair should ensure that the CFD box includes the whole annular ring.