Learn how to assess the aortic valve (mid-esophageal long-axis view) using TEE in this short video by cardiology expert, Andrew R. Houghton MD.
This video was taken from our CME accredited Transesophageal Echocardiography (TEE) Essentials course taught by Andrew Houghton, MD–Cardiac imaging specialist and head of cardiac imaging at Grantham & District Hospital.
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[00:00:00] In this lesson, we're going to learn how to obtain the mid-esophageal long-axis view of the aortic valve. In this view, we have the left atrium in the near field, the mitral valve, anterior and posterior leaflets, the left ventricle, the left ventricular outflow tract, the aortic valve, and the aortic root to gather a portion of the right ventricular outflow tract. This view is obtained at the mid-esophageal probe
[00:00:30] position, with the probe facing anteriorly, to take a cut through the aortic valve. In order to obtain the long-axis view, I'd suggest starting with the aortic valve short-axis view, that we covered in our previous lesson. And this is obtained with transducer imaging plane angle of around 40 degrees, certainly somewhere between 25 and 45 degrees. And once you've obtained this view, then what we need to do is rotate
[00:01:00] the imaging plane forwards by 90 degrees, to obtain the long-axis view. So here, we now have the mid-esophageal long-axis view. We have the left atrium in the near field, mitral valve, left ventricle, left ventricular outflow tract, aortic valve, and aortic root. We've used a transducer imaging plane angle here of 137 degrees because that gave us the optimal long-axis view, with no foreshortening.
[00:01:30] Certainly, the optimal view will normally be obtained with an imaging plane somewhere in the region of 120 to 140 degrees. Looking at the aortic valve itself, we can see two cusps, here. The cusp in the far field is the right coronary cusp. The cusp in the near field is either the non-coronary cusp or the left coronary cusp, depending upon whether the probe is turned to the patient's right or the patient's left.
[00:02:00] So, by adjusting the probe position and turning it left or right, we can sweep back and forth across the valve and bring either the left coronary cusp or the non-coronary cusp into view. In this particular case, what we're seeing is the non-coronary cusp, together with the right coronary cusp. In this view, we can assess the morphology of the aortic valve cusps whether they are not thin or thickened, whether they are calcified, and whether there are any associated
[00:02:30] abnormalities such as vegetations. We can also assess for mobility of the cusps and how widely they open. Remember to take a look as well at the anatomy of the left ventricular outflow tract for any subvalvular stenosis and also the aortic root to look for any supravalvular stenosis or any aortic root abnormalities. And we'll discuss the aortic root in more detail in our chapter
[00:03:00] on the aorta. Finally, once we've assessed the anatomy of the aortic valve and neighboring structures, we should apply color Doppler to assess flow through the valve. And here, we have color Doppler applied in a patient who has severe aortic regurgitation, as a consequence of infective endocarditis. And we can see this diastolic, very broad jet of
[00:03:30] turbulent flow, which corresponds to severe aortic regurgitation. We should also take some measurements in the long-axis view. One of these is the diameter of the left ventricular outflow tract and this measurement is normally taken within half a centimeter of the aortic valve annulus. This measurement is used as part of the continuity equation when calculating effective orifice area of the
[00:04:00] aortic valve, particularly useful in cases of aortic stenosis. We should also measure the diameter of the aortic annulus, between the hinge points of the aortic valve. In this measurement, together with the previous LVOT diameter measurement, should be taken in early to mid-systole. Other measurements of the aortic root are discussed further in the chapter on the aorta. Finally, let's take a look at a couple of examples of
[00:04:30] pathology. This is a patient with severe aortic stenosis and this mid-esophageal long-axis view of the aortic valve shows thickened and calcified aortic valve cusps, with greatly reduced cusp mobility. And here, we have a patient with infective endocarditis. They have an irregular mobile oscillating vegetation on the ventricular aspect of the non-coronary cusp.