STS Video Blog #4: “What About Horse (Equine) Tissue For Heart Valve Replacements?” By Dr. Allan Stewart

By Adam Pick on February 13, 2011

During the 47th annual Society of Thoracic Surgeons meeting last week, I received a great question from Keith about the use of horse (equine) tissue in heart valve replacement devices. Keith wrote to me, “Adam – What can you share about aortic valve replacement surgery using horse tissue?”

Luckily, I was able to discuss this topic with Dr. Allan Stewart at the convention. Dr. Stewart, who practices in Miami, is one of the most experienced heart valve surgeons with horse valve replacements — like the ATS 3f Aortic Bioprosthesis manufactured by Medtronic.



As several members of our patient and caregiver community are hearing impaired, I have provided a video transcript below.

Adam: Hi, everybody. It’s Adam and I’m here at the STS convention in San Diego. I’m very fortunate to be standing next to Dr. Allan Stewart and we are answering your questions that you posted at We have a question for Dr. Stewart from Keith Barker. Keith asks, “What can you share about aortic valve replacement surgery with horse tissue?”

Dr. Stewart: Well, why replace a valve with horse tissue? It’s almost become now like an animal farm. There are pigs. There are cows. There are horses available. And people are surprised because it’s less well known, but the transcatheter valve, or the valve without opening your chest, was initially conceived with horse tissue and here’s why. The tissue has got more textile strength and is actually very thin in appearance. Also it lacks — One of the important things that ruins valves, something called phospholipids. They’re very low in concentration in horse tissue — which is why it’s ideal for a valve replacement. Nowadays, it really doesn’t much matter what the tissue is made of but it matters how the valve is designed. The structural engineering of all the newer valves is much more advanced than it was earlier. I believe that this horse valve replacement tissue combined with the valve structure will make it last 15, 20 years.


Horse Valve Replacement Tissue Device
ATS 3f Aortic Bioprosthesis (Horse Valve Replacement By Medtronic)


Adam: Great. You mentioned the cow valves, the pig valves. You mentioned, obviously, the horse valves. In terms of how common a valve replacement is done with the horse tissue valve, is it very common? Because I’m sure a lot of patients, they’re more familiar with pig valves and cow valves.

Dr. Allan Stewart, MD: Well, the pig valves and cow valves have been around for about forty years now. The equine, or horse valve tissue, has only been around for about nine years and, really, our longest experience was in Europe, in Germany and Belgium, who have done a fair bit of implantation. It’s been out that long but, unfortunately, we can’t start with a new product and immediately have twenty-year results. We’ll have to wait and see. All of these valves be it porcine, or pig, or cow, or bovine, have all been tested on the same rapid testing method while which will give a lab results of twenty-year data but, really, we need to wait for twenty-year data from a human being.

Adam: So, in terms of that testing, you’re talking about the valves are actually put into some kind of experience where they’re pressurized and challenged to be very similar to a human heart valve, correct? Is that right?

Doctor Stewart: Exactly, Adam. What occurs is put into something we call a rapid accelerator where the valve is opening and closing several hundred million times to replicate the decades of life in someone but, unfortunately, it’s not subject to the same emotional stresses and blood and changes in doing exercise as a valve would be when it’s sewn into a person.

Adam: Right. Well, thank you very much for your time, Dr. Stewart. Again, this is Dr. Allan Stewart, MD who’s practicing in New York City and you can learn more about him by going to Thank you very much.

Dr. Stewart: Good to see you again!

Keep on tickin!

Written by Adam Pick
- Patient & Website Founder

Adam Pick, Heart Valve Patient Advocate

Adam Pick is a heart valve patient and author of The Patient's Guide To Heart Valve Surgery. In 2006, Adam founded to educate and empower patients. This award-winning website has helped over 10 million people fight heart valve disease. Adam has been featured by the American Heart Association and Medical News Today.

Adam Pick is a heart valve patient and author of The Patient's Guide To Heart Valve Surgery. In 2006, Adam founded to educate and empower patients. This award-winning website has helped over 10 million people fight heart valve disease. Adam has been featured by the American Heart Association and Medical News Today.

Blaine Molsberry says on February 13th, 2011 at 9:35 pm

Hi Adam,
My question pertains to the transcatheter valves in trials.
1. When are they expected to be approved in the USA?
2. Are they testing a procedure to remove and replace them through the vain also?
3. Are there any drawbacks to the transcatheter?
The leakage on my aortic valve is currently holding steady and my heart is not inlarging.
Your book and blog has given me much comfort for my future. Keep up the good work.
Blaine Molsberry

Tom Brighi says on March 27th, 2011 at 10:16 pm


Thanks for your website and blog… the information that you provide is priceless and I could not have made an educated decision without it! In December 2010, at 47 years old, I was diagnosed with endocarditis. By the time the infection was properly diagnosed, and a treatment plan implemented, extensive damage had occurred to my aortic valve and surgery to replace the valve was recommended.

Of course, I was like everyone else who gets the diagnoses that valve replacement surgery will be necessary. What do I choose… a Mechanical or Tissue valve replacement? What can I expect before, during, and after surgery? What are my options?

Then I came across your blog on the ATS 3f Aortic Bioprosthesis (Horse valve replacement by Medtronic) and your interview with Dr. Allan Stewart. This valve and the fact that it showed so much promise in design, durability, and future replacement via trans-catheter procedure more than intrigued me. On 02/17/2011 I had heart surgery at St. Luke’s Episcopal Hospital in Houston TX to replace my aortic valve. Dr. James J. Livesay of the Texas Heart Institute performed the surgery and I chose the ATS 3F equine valve. On March 14th I had my first echocardiogram and it was spot on. No leakage, and as all the information I was able to get my hands on prior to my decision to use the ATS 3f Aortic Bioprosthesis stated, as close to a native valve as I could get. My Cardiologist, Dr. Andrew Civetello stated, “It is very difficult to tell the difference between a native valve and the ATS 3f”. I understand that there is no long-term data available, however, to this point I am satisfied with my choice.
Again, thank you!

jaycee says on March 28th, 2011 at 1:52 pm

The transcatheter approach has still not been approved in the US by the FDA but has been used in Europe for a while I hear. Would anyone be able to compare the TAVI (transcatheter aortic valve implantation) in Europe to the US ? I hear doctors from Europe are training doctors in the US. That would make me believe that the Europeans are experts at this.

Elizabeth P. Walz says on October 23rd, 2013 at 1:32 am

I received a horse aortic valve replacement in Oct. of 2011. Within 2 months when I went back for a echocardiogram they found that the valve was leaking. By the end of a year it was right back to where it was before surgery. Now I am told that a second operation would not be a good idea. I am very confused. Also I was hoping for the new surgery where they go in through a vain but was told that they don’t do that for second operations. I was also told that a horse valve if not really a valve from a horse but is called that because it sounds like a horse. Your information seems to say otherwise. It is very hard to get straight information. Can you help me. Elizabeth

Lee Wibert says on July 7th, 2014 at 1:16 pm

I am to have a replacement aortic valve soon. Not mechanical since I am 78. I am in good shape and very active other than getting more out of breath now. which valve to use is my problem. thanks Lee

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