The Garden Hose Effect

It is common wisdom that the direction of a regurgitant jet reveals the mechanism of mitral regurgitation: a posterior/lateral jet direction suggests a flail leaflet or prolapse of the anterior leaflet, whereas a jet oriented in anterior/medial direction is indicative of a flail or prolapsing posterior leaflet.

A strange jet

Today I would like to show a jet that has a very peculiar flow direction. Let me first show you the color 2D images of this patient (click on images for video).

Color Doppler (two-chamber view) study of a patient with severe mitral regurgitation.

Can you identify the mechanism of mitral regurgitation merely from the color Doppler study? What is the direction of the jet? Rather difficult to tell, isn't it?

The TEE study will reveal the problem more clearly:

Transesophageal study (Four-chamber view).

The diagnosis is clear

You will all agree that she has a myxomatous mitral valve with mitral valve prolapse of the posterior leaflet. A small portion of the valve also seems to be flail. This explains why the jet is directed rather medially. This is not uncommon. Quite often a prolapse is confined to just one leaflet or even a specific scallop of a leaflet. For a detailed analysis of the jet, here is the corresponding color Doppler study:

Transesophageal study (four-chamber view) now on color Doppler.

Spray it!

I am sure you can now appreciate the dynamic change of flow direction of the jet during systole. It is initially rather central but gradually turns into medial direction - similar to a loose garden hose that sprays water in an arch. Why does this occur? Simply because the orientation of the regurgitant orifice (or channel) changes over time. This is related to the dynamics of mitral valve prolapse. During systole there is an increase in the degree of leaflet protrusion into the left atrium. The symmetry between the anterior and the posterior leaflet changes, and so does the direction of the jet.

“Three Dee”

This can also be appreciated on 3D echocardiography:

3D echo study showing prolapse of the posterior mitral valve.

The posterior leaflet is to the right. You can see that a prolapse is present in a portion (the medial scallop) of the posterior leaflet. If you look at the motion of the prolapse and its relationship to the anterior leaflet, you will be able to appreciate why the jet direction must be anterior and why the direction changes during systole.

So what?

What is the consequence of this finding? Well, honestly, in this specific instance it is of no major consequence. It will not affect the diagnosis and its implications for therapy. The patient has severe mitral regurgitation. From the 2D image one can tell that this valve is ideal for mitral valve repair - simply because it is a rather “localized problem” and because the middle scallop of the posterior leaflet is affected. Surgeons rather like this type of defect: they usually perform a quadrangular resection of the diseased segment together with a so called “sliding plasty” to mobilize and readapt the annulus; that would account for the smaller mitral orifice. As in all patients undergoing mitral valve repair, an annuloplasty ring would prevent dilatation of the annulus.
However, this case serves to understand relationships between the anatomy, pathology and color Doppler. This, in turn, will help you to interpret many phenomena related to valve pathologies. The knowledge can be of great use in many situations. Do you remember one of our latest mitral valve cases called "Catching the moment" and the patient with a bileaflet prolapse?  That was also an instance in which the morphology of the valve explained the presence of mid- to late mitral regurgitation.
Finally, isn’t it fun to find strange things once in a while? Certainly something you can impress your colleagues with!

How YOU can excel in echo...

If you want to excel in echocardiography and become a true champion, then check out our Masterclass, which is currently open for registration. There's no better way to start the new year than with a new clinical skill. So hop on board and join thousands of colleagues who have already learned echo from us.

Tommy Binder