North “Stars” and Aortic Stenosis

Recently, I was invited to the Karolinska Insitute in Stockholm to hold a lecture. This gave me both the opportunity to present some echo cases but also to meet with friends: Fredrik Brolund and Prof. Reidar Winter. Fredrick Brolund is one of the driving forces responsible to train sonographers in Sweden. We met many years ago during the legendary Skepper Holms courses, which at that time were organized by Prof. Kaj Lindvall and Prof. Per Carlens.

Program of the 12th Skeppar Holms Echo courses from 1997

Here is a short interview where Fredrik shares his views on education and the role of sonographers.

Prof. Reidar Winter has now organized the “sequel” to the Skeppar Holms courses. The three-day course was a full success packed with high quality lectures. Special highlights were the live demonstrations from the echo and cath labs.

I was invited to present a few echo cases. One of these evoked much discussion. It was a case that dealt with aortic stenosis and the indication for aortic valve replacement. As in many western countries, aortic stenosis is also on the rise in Sweden. In the western world it is now the third most common cardiovascular disease following hypertension and coronary artery disease. The increase in aortic stenosis is the result of the aging of our population. This together with new treatment options changes our approach to this disease.

Since it was such an interesting case, I would also like to show the case to you. How would you manage this patient?

No symptoms

The patient is a now 72-year-old man and a former long distance runner. In the 60ies he won the Austrian marathon championship three times.  For all of you who are familiar with marathon running his record time is 2 hours and 27 minutes! He is still in very good shape and loves to cycle. His tours last for several hours and take him over some of the highest mountains of Austria. He has absolutely no cardiovascular risk factors. However, there is one problem: He has severe aortic stenosis.
 
Six years ago when I first saw him, aortic stenosis was only moderate but his gradients gradually increased.

CW Doppler signal across the aortic valve recorded 6 years ago. Aortic stenosis was moderate then, the maximum gradient was 60mmHg and the mean Gradient 33mmHg.

Here is his current echo (click on images for video):

Calcified aortic valve. The mean gradient is now 58mmHg, (max gradient = 105mmHg),the AVA is 0.8cm2, left ventricular hypertrophy is severe and his ejection fraction is normal.

What would you tell the patient?

How, would you manage such a patient?

Well, you might say that there is no need to operate since he is asymptomatic and left ventricular function is superb. Therefore, his prognosis is good. But then again - do you feel comfortable letting the patient ride the bike?  Sure you could tell him to leave the bike in the garage. But that was no alternative for the patient. He was only willing to restrict his tours somewhat and monitor his heart rate. And what about left ventricular hypertrophy? At this time his septum measured 16mm. What if we don’t operate? Will it progress and lead to irreversible fibrosis of the myocardium? And finally, he wont get any younger, aortic stenosis will increase for sure. Should we really wait for co-morbidities until we finally operate?

Not an easy decision

When I asked for the opinion in the audience at the Karolinska Institute there was a small majority opting for surgery.
 
But what about the risk of surgery? If the operation does not go well then you are to blame. To make things even more complex, our patient is also a medical doctor and his son a cardiologist. Don’t forget - he is doing well. With a prosthetic valve he will be at increased risk for prosthetic valve endocarditis. You could spare him several years of this risk if you just waited. And finally, how reliable is echocardiography in this setting. He has bradycardia and has a high stroke volume. This affects the gradients. So maybe we are simply overestimate aortic stenosis. Take a look at the left atrium it is only mildly enlarged. Hypertrophy is certainly also caused by training and in this patient is not only due to aortic stenosis.
 
Maybe transfemoral aortic valve implantation (TAVI) is a solution. But honestly, he is also a good surgical candidate and there is currently nothing to support TAVI in such patients.

A few more bits of information:

We wanted to go the “whole nine yards” and so we collected as much information as possible: His exercise capacity during a stress test (bicycle) was superb (164%). The ECG was ok, there was no blood pressure drop. His NT Pro BNP levels were also normal. We even performed an echo during theophylline infusion to increase his heart rate. Here is what happened:

Baseline Echo top, Echo with theophylline bottom. The heart rate increased from 55 to 67 beats/minute.The gradients dropped slightly to a max gradient of 79mmHg/ 51mmHg. Still aortic stenosis remained severe.

And finally we also performed a speckle tracking analysis to look at longitudinal strain:
 

Just to give you a short explanation what information this might provide: It is now well recognized that longitudinal function is an early marker of left ventricular dysfunction; especially in patients with aortic stenosis.
There is also evidence that the degree of longitudinal dysfunction correlates with the severity of AS and that it can help to determine when aortic valve surgery is required.

Bulls eye display of longitudinal strain: Global longitudinal strain is reduced (- 12.5%) and shows the typical pattern with a more pronounced reduction in the basal segments.

So it seems his left ventricular function is not so good after all. This is an additional, (but as I believe) important piece of information.

What we did:

Eventually together with his son (who knew him better than all of us), we pressed for surgery. The preoperative coronary angiogram was normal and he received (a large) bioprosthetic valve. And what happened? It was not a fast victory. He experienced a local complication and suffered long from recurrent atrial fibrillation. But, six months later he was back on his bike as if nothing had ever happened. As a matter of fact his exercise capacity is even better after operation than before.
 
Here is his postoperative echo:

Postoperative Echo, left ventricular function is good and the bioprosthetic valve works perfect.

A happy ending, but this case shows how many factors must be considered when making a decision. You need a thorough understanding of cardiac pathophysiology, clinical cardiology and echocardiography. Exactly this is what we teach in our lectures. So don’t wait and sign up now for our courses at: www.123sonography.com