Aortic and arterial aneurysm

[mtstreet]

Hi,

I am a 52 year old female with a history of two previous heart surgeries due to a bicuspid aortic valve. The last surgery was in 1999, when my aortic valve was replaced and an aneurysm repaired.

I've had yearly echos since then and they've been fine. However, last year I asked my cardio to do a CT after reading about how bicuspid valves are more prone to aneurysms. Lo and behold, the CT showed an ascending aortic aneurysm measuring 4.5 cm. There were also aneurysms in the brachiocephalic artery (it measured 2.6 last year) and at the origin of the left common carotid artery. (1.8 cm.)

My cardio's nurse said that the aneurysm was "mild" and didn't seem concerned. The only thing said to me was that I'd have another CT this year. However, when I called to schedule this year's tests they would only set up my echo and - if I understood them correctly - a CT might not be scheduled depending on the results of the echo.

So my first question is: do aneurysms normally show up on an echo? Why did they show up on the CT scan last year but not the echo?

My second question is: I understand ascending aortic aneurysms are repaired at roughly 5 cm, though that threshold may be lower for me because of my small size. So I realize 4.5 is not critical, but can you tell me about the two arterial aneurysms? What are normal measurements for the brachiocephalic and left common carotid arteries?

Thanks in advance for any information.

[John Kenyon, CNA]

Hello -

Before we go into trying to answer your questions I'd like to ask one of my own: Do you by any chance have any connective tissue disease such as Marfan syndrome or Ehlers-Danlos disease? I only ask because while bicuspid aortic valve is a heritable abnormality that often is accompanied by a lifetime risk of ascending aortic aneurysm, you seem to have had quite a few aneurysms or at least dilations and only now have had the expected one show up. Which artery was involved in the aneurysm repair fixed at the time of the valve replacement?

Now then: while the ascending aortic aneurysm is hardly surprising in light of the presence of the (formerly) bicuspid aortic valve, these are sometimes difficult to visualize on echo because of the positioning of them, and a transesophageal echocardiogram or TEE (with the sonagraphic element passed down the throat to get a far better view) is preferable (maybe that's what's planned?), and after that MRI or CT imaging. Still, if it showed up on CT before, that's reasonable; often they can't be seen on regular echo. A TEE will give the best visualization of this area as a rule.

Your current problem is a notable dilation (4.5 cm) whereas the point at which an otherwise "normal" person would be said to have an actual aneurysm at 4.9 cm, and for someone with Marfan's, the "cut point" is 5.5 cm.

There is no precise measurement for the brachiocephalic or inominate artery, since it comes off the aorta directly; rather, there is a complex formula for determining what it "should" be, and usually an aneurysm is diagnosed based upon visual difference between any segment of it and the remainder. Having this dilate with the ascending aorta is not at all unusual because of the close relationship.

The same holds true for the left common carotid, which also takes off from the aorta. This is often involved by direct association. This suggests the dilation involves the aortic arch, and these arteries are usually partially replaced during graft repairs out of anatomic necessity anyway.

Given the arteries involved, and the relatively small dilation of the affected aortic segment so far, you'll probably be evaluated for the sake of a more precise measurement of the current dilation and then followed to determine if and when you'll need to have it repaired. When and if you do, those others, which are incidental to the main one, would be repaired along with it.

I hope this is helpful to you. Please follow up with us here as needed. Best of luck to you.

[mtstreet]

Hi John,

Thanks so very much for your informative reply. It certainly was helpful. I do not have Marfans or Ehlers-Danos and no one else in my family has a BAV.

I had my annual echo yesterday (no, it was not a TEE) and see my cardio next week. I imagine she'll do further tests to see if the aneurysm has grown. It really makes me glad that I pushed her to do the CT or else I would never known it was there.

I like your use of the reassuring phrase "when and if" regarding a repair. : ) My second surgery was complicated by scar tissue from the first operation, which caused my right ventricle to become stuck to my sternum. According to the surgeon it's still stuck and makes any redo rather risky.

Again, thanks a lot for the reply. I appreciate it.

Cheers!

[mtstreet]

Hi again,

One more question. You mentioned that my measurements suggest an involvement of the aortic arch. Here are the measurements from last year's CT:

-the diameter of the aortic arch between the brachiocephalic and left common carotid artery is 3.0.
-between the left common carotid and the left subclavian artery it measures 2.0
-diameter of arch justdistal to the left subclavian artery is 2.8

Can you tell me if these measurements are normal?

Any info will be appreciated.

Thanks a lot!

[John Kenyon, CNA]

The numbers suggest a small-to-normal sized arch, which is odd, because that would mean those other smaller take-off vessels are developing aneurysms independent of the ascending. This would suggest some sort of genetically-transmitted disease, since generally these dilate from their respective roots as the arch dilates.

Of course, I'm not looking at actual pictures of all this, and if I were it might make more sense than it seems to in some other way. At any rate, please continue to keep us updated. I hope this answer is in some way helpful. Continued good luck to you.

[mtstreet]

Hi John,

Again, many thanks for the information.

The report made no mention of a problem with the arch so I got the impression that these are separate aneurysms. I know there are limitations since you haven't seen the pictures, but you're saying that the arch doesn't appear dilated at this time, right? And under normal circumstances it would be, given the dilations noted in the other arteries, right?

I'm unaware of having a genetically-transmitted disease that would have caused this but have never been tested for anything.

Hmmmm....this is all very interesting. I didn't have a follow-up appointment last year to discuss the results of this test so when I looked at the report again recently I began to wonder about those other arteries. Are there any specific questions you might suggest I ask the cardio when I have my appointment this week?

Thanks again for your time and all the wonderful information. Best wishes.

[John Kenyon, CNA]

Again, you're very welcome.

Yes, you read me correctly. The arch doesn't appear to be dilated (at least to any remarkable degree -- it is often judged based on the surrounding anatomy, but it certainly doesn't look big by the numbers), and usually the take-off arteries, when they also have aneurisms, have them as part of an extension of the dilated arch, not as completely separate entities. I may be reaching an incorrect conclusion based on having to visualize using written info and numbers, but it sounds as though those other ones have developed independently, which is odd if I understand the situation correctly, and this would usually only be due to some sort of connective tissue disease that is inherited. Of course if I could see the actual pictures it might make more sense.

One thing that strikes me about the sizing of your aortic arch is that there is a distinct 1.0 cm narrower area between the left common carotid and left subclavian arteries. While this isn't a remarkable difference, and the overall size of the arch seems pretty normal, especially compared with the ascending leg, I'm wondering if the problem might not be due to a very slight coarctation (narrowing) of the aorta in that segment. This is often seen with BAV, but usually just beyond the roots of the takeoff arteries, instead of between some of them. It's also a pretty small degree of narrowing, possibly within normal limits. Still, it's an almost 30 per cent reduction in diameter at that point. This could possibly bear some relation to the rest of the dilated takeoff arteries. I'm no thoracic surgeon (or any other kind of doctor) but this is the only thing I can draw from the information. The arch is normally pretty consistent in its diameter, and your ascending portion is definitely dilated compared with this.

It's a puzzle for sure. I hope this is in some way useful to you. It at least raises some questions. I'm sure your doctor has a pretty good idea as to its importance, but it might be worth asking about it.

[mtstreet]

Hi John.

Well, we'll see what the doctor says on Thursday.

Hate to bother you, but now I have a couple of unrelated question. The report from my echo last week was normal except it reported that the apex of the left ventricle is hypokinetic. I understand the meaning of the word hypokinetic, but can you explain what significance this has? Also, the aortic root has shrunk from 3.0 last year to 2.0 this year. Is this important?

Thanks!