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Cases

Crush It

Fri, 09/11/2012

 


Here's today's case...

Thanks for your comments on our last post and the numerous suggestions on how the patient with obstruction of the bioprosthesis and right heart failure could be treated. As I had promised, I will tell you what we did. Read this report and you will find out.

Crushed valve
First, I want to show you a technique that has become available in the last few years and is truly a breakthrough in the treatment of aortic stenosis. Many of you will have heard of TAVI (transpercutaneous aortic valve implantation) - a technique that has been used in more than 20,000 patients throughout the world.

TAVI permits implantation of a bioprosthesis in patients who cannot undergo surgery either because they are too old, or because they have several co-morbidities such as renal failure of poor left ventricular function.

Two types of valves are used at the present time: one is placed on a balloon introduced into the stenotic aortic valve via a left heart catheter. The balloon is inflated, and the prosthesis expanded and placed in aortic position. The native aortic valve is crushed and expanded to the aortic sinus.
 
 

 


  The valve is placed on the top of an expandable balloon.

 



Edwards Sapien valve (bioprosthesis)

 
The procedure
Let me show you a TEE study of what is done during the procedure. Here is the TEE of a patient with aortic stenosis. Echocardiography is used to measure the size of the aortic annulus. This measurement, and measurements obtained with CT, are used to determine the size of the prosthesis.

 


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TEE - long-axis view showing the calcified stenotic aortic valve.

 
A balloon is used to expand the valve. This is done under rapid pacing to prevent excessive motion of the valve.

 
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A contrast-filled balloon is inflated during rapid pacing
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The valve is introduced into aortic position and inflated. You can see the valve as it expands.
 

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Now the valve (on a balloon) is inflated in aortic position
.

 
After the procedure the patient has mild aortic regurgitation - certainly something he/she can live with.
 

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Mild paravalvular aortic regurgitation after the procedure
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The risks
The procedure is not devoid of risks. The position of the valve may not be optimal, or it may embolize during the procedure. Patients may experience a stroke caused by dislodged aortic debris, or develop a left bundle-branch block or a conduction abnormality requiring a pacemaker. Vascular complications are another problem, because the catheter and sheaths required for implantation are rather large and rigid. Still, a number of advancements are in progress, permitting the procedure to be used in a lower risk population as well.
 
The ignorant revisited
Back to the "ignorant" patient in our last post. The patient obviously needed diuretics for the treatment of right heart failure. We also tried prostanoids in an attempt to reduce his pulmonary pressure (based on the fact that he had mixed - pre- post capillary pulmonary - hypertension). Unfortunately, nothing really helped. The patient deteriorated rapidly.  We also thought of balloon valvuloplasty of the mitral valve, but it was too calcified and we were afraid he would develop acute mitral regurgitation.
 
Despair
In sheer despair we tried something entirely new. We implanted an aortic valve - the same one described above - into the mitral valve bioprosthesis using a minimal surgical approach. I would have been glad to tell you that we saved his life but unfortunately, while preparing this post, he died just 4 days after the implantation. I presume he really did wait too long.

So take care and I'll talk to you later

yours Tommy Binder & the 123sonography team