Dr. Glenn Barnhart provides educational material for young surgeons and surgical trainees so that they may adopt successful techniques related to the On-X aortic and On-X mitral heart valves.
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On-X® Prosthetic Heart Valves IFU’s
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My name is Dr Glenn Barnhart. And I've been asked by a cryolife too, talk about the onyx valve and specifically to provide educational material for young surgeons just starting out and surgical trainees. Uh so that they may adopt techniques that are uh successful with the use of the onyx valve. My background is having done training at the Medical College in Richmond Virginia as well as that. The National Institutes of Health in boston Children's Hospital. I practiced at the Medical College of Virginia as well as Sentara Heart Hospital in Norfolk Virginia for nearly 20 years and then was asked to be executive director of the Swedish Heart and Vascular Institute and Swedish Medical Center as well as chief of cardiac surgery there in Seattle, where I was for approximately 11 years and recently have retired. So my experience with annex starts in 2006. When I first started in planning the valve, I was the principal investigator at Sentara Heart Hospital where I was at practice at the time. I started using the valve around that time as part of the Proact trial which was of course under F. D. A. Um clinical trial guidelines. And I moved to Swedish Medical Center in 2000 and seven and continued the use of the valve there. Um I have implanted over 200 onyx valves both in the aortic and mitral position. I certainly think it's the valve of choice. Let me speak for a couple of minutes about patient selection with both the onyx aortic economics mitral valve. I think it's very important that guidelines are followed. Certainly there are tradeoffs for any valve that we use. There's no question about that whether it's mechanical, bio prosthetic or tab are um there are a number of factors that need to come under consideration when one is choosing a valve for a patient. I think the conversation with the patient is also extremely important, patients need to understand and our job, I think is job number one is to make sure the patient is completely informed. And part of that informed consent is the longevity of the valve and how long it's going to last. And there is very little question about that in today's world, that mechanical valves will last longer than any bio prosthetic valve in the market and any tab are on the market. The study that we would all like to see is a randomized prospective study lasting 35 to 40 years between mechanical versus bio prosthetic valves versus tab are, that is a study that is impossible to do. So we have to extract from the literature what we know about the longevity and the durability of mechanical valves versus bio prosthetic valves versus tab are. And I think there's no question that mechanical valves wins that race every time. Now there are trade offs. Currently, it does require Coumadin therapy and many patients do not like to think of having to take cumin and not having their blood drawn on an interval basis. However, patients need to understand if they are choosing a bio prosthetic valve over a mechanical valve, that they are going to be possibly limiting their lifespan from a statistical standpoint. So it's very important that they understand that I feel as a surgeon job number one is to make sure that that we are providing the patient with as long of a normal lifespan as possible. Additionally, let me comment on the patient's informed consent regarding re operation and further procedures on an interventional basis for tab are I think that all of us, as surgeons accept the fact that having a re operation carries a higher risk. There is no question about that in today's hands. It's a reasonable risk, but still it's a higher risk than the first time operation. So all of those issues I think need to be discussed with the patient in a very uh patient friendly manner. So they understand exactly the choices that they're making for themselves and their family, considering all the aspects when it comes to valve choice regarding mechanical versus bio prosthetic versus to bar. Uh This brings us back again then to consideration of mechanical valve and specifically on X. We know now that the proact trial clearly has shown that the valve can safely be used with an iron are of 1.5 to 2.0 uh that was approved by the FDA in 2015 and has made it into the updated A. J. A. C. C guidelines in 2017. Uh Also the uh mitral valve is currently on a clinical trial. Uh enrollment in that trial is complete. While that still is being on Coumadin. It is a substantial reduction in the amount of bleeding risk to the patient, reducing that patient from an iron are of 2.5 to 3.5 down to two point oh 22.5. All of us have taken care of these patients over the years recognized the fact that overshoot occurs commonly with Coumadin. And so if you're over shooting in a range from 2.02, versus over shooting at a range from 2.5 to 3.5, the less there is much less likelihood of having a significant bleeding complication uh, in the patients who have the lower iron are so I think this is going to be a very significant improvement in patients with mechanical mitral valves. So patients who are have a mechanical mitral valve being in a lower I and our two point oh 2.5 will definitely be an improvement for that patient population. In that there bleeding risk will be substantially reduced. So what we are demonstrating here is that you can see we've put a mitral prosthesis in place. This is a 25 33 conform X mitral valve replacement in the pig heart. And then if you look through the aorta here, which has been transected, you see the leaflets here and here and here and what I'm demonstrating to you is that there is as always a fair amount of distance between in the order of micro curtain where the micro analyst has been fixed to the anti relief of the mitral valve. Um That is a fair distance from the, from the aortic aneurysm. So what I'm gonna do now is remove the tissues as remove the aortic leaflets as if we were doing an aortic valve replacement along with the micro valve replacement. So we're going to be doing a double valve here and I think it's very important to keep in mind that always going to be probably getting in a size less on the aortic valve than one had initially measured. But one should always measure the aortic valve analysts first when doing a double valve and then go do the mitral valve and then come back and do the aortic valve. And you will find that usually it's going to be one size less in the aortic position. Not so much that this prosthesis sets down in here. Shorten the aortic valve, but it stiffens this area of the order michael curtain so we still have a fairly good size aortic annuals. So you can see in this particular specimen that we have implanted a conform X. A. Next mitral valve 25 33. In the micro position, we have unruffled the left atrium and that's that's why that's so well exposed. The purpose of this specimen is to demonstrate how close the relationship is. Here. We know between the anti relief of the mitral valve and aortic annuals. However, there is Usually at least 3-4 mm from here down to here. What you're seeing here are the pledge. It's in the micro valve. Angeles and the aortic analysts actually is up here is where your searches will be going. So there really is no way there could be any conflict between The two valves in terms of the um outlet of the micro valve and the inland of the aortic valve. So what we're gonna do next is go ahead and put suitors in the um native aortic Angeles and do complete our double valve replacement. So now you can see, we put in all the futures in the aortic annual ist. Once again, I want to point out these are the futures and the aortic analysts and these are these futures that are actually underneath the sisters in the arctic analysts in the micro analyst. So there is plenty of space in there for those two valves to not have conflict. I think 23 is going to be about right because this will, this will come over once we put the suitors in the valve and you can see there how the replica conforms nicely to the, To the ambulance. So let's go with a 23. So this is a 23 that you can see and we're going to be using this valve for implantation here, a double valve. We put the three rommel's down now using that technique to demonstrate that and I'm gonna now open this and look for any pledges that you can see. I think you can see um back here that there are some pledges that are out. So I'm going to focus on that area first and make sure that those pledges recede back up against the valve housing there, there's a pledge it right at the tip of my right there you can see. So we're going to keep this open and make sure that that pledge it recedes the pledge, it now has actually receded back up underneath the housing, the valve, which is desired outcome. And I'm gonna keep tying along here for now because I've got a couple of other pledges along here that are still out outside the the housing. So these three Romel suitors will remain in place and keep the valve in its position secure within the analysts until I finish tying these in and then we'll come back to the rebels and tie them last. So as you can see, we have completed the valve implant. We've left the three rommel's on, you can look in through the orifice of the two leaflets, you can see that there is no tissue anywhere down inside. There's no pledges or anything hanging out. They've all recessed behind the housing. We're going to demonstrate the use of the corn ought in these last three, which I think is a um an alternative approach. That's quite good, especially if you're doing multiple valve replacement just from a time saving standpoint. And I think the not itself is at least as good, if not better than what we tie as surgeons that goes down, compresses the tissue and then fires. The double valve replacement is complete. So you can see that this is the plastic probe that I'm placing through the mitral valve prosthetic on x mitral valve that we have previously implanted, and these are leaflets that are opened in the aortic valve, and this probe is quite far from the housing and the flair of the aortic valve. So there's no conflict between the two valves. And in my experience of doing numerous double valve replacements with double onyx valve, I've never had any problem with any sort of conflict.