On-X Valve Questions

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T

T in YVR

Well-known member
Joined
Feb 21, 2013
Messages
241
Location
North Vancouver, BC, Canada
Hey there,

I finally meet my surgeon Wednesday (re: AVR) and I have 2 questions I was hoping someone may have insight on -

1. I keep hearing/reading about the future potential of perhaps only requiring aspirin instead of Warfarin/Coumadin if on the On-X valve. What is driving this possibility? Is it further testing/trials on whether aspirin effectively controls the chance of a clot (which may benefit some of those who have the On-X valve I assume) or is it physical changes to the On-X valve itself (which would only benefit new recipients)?

2. Other than differing sizes, does everyone pretty much have the same On-X valve? Or are there newer versions of this since it was introduced? I can't imagine a new version of an On-X valve comes out very often due to the extensive testing/approvals etc does it? If there is a "latest and greatest" version, I would like to ask my Dr. if he uses it.

Thanks!
Tony
 
T,

1.) The most recent results seem to show that reduced Warfin (INR 1.5-2.0) + Aspirin is better (less bleeding, no significant increase in stroke events). I haven't heard anything about the Aspirin + Plavix results. There are no trials with Aspirin only. The reduced Warfarin trial is for higher risk patients but if the FDA approves this lower INR, it seems it could be of benefit to anyone with the On-X.

See the following related thread:
http://www.valvereplacement.org/for...t-for-Reduced-Anticoagulation-with-On-X-valve


2.) As far as I know, there is only one current model of the On-X and the design has not changed significantly since 1996. Although there is a different one for the Mitral valve vs. the Aortic Valve and there are 2 different kind of cuff, or sewing ring options (normal cuff vs. Conform-X cuff, the latter being easier to install on some mitral valve patents).
 
Well, looks like I got an answer direct from On-x (re: On-X for AVR)....I suppose I should have checked with them first. For those interested, I'll re-post here - this is what they said:

1. I keep hearing/reading about the future potential of perhaps only requiring aspirin instead of Warfarin/Coumadin if on the On-X valve. What is driving this possibility? Is it further testing/trials on whether aspirin effectively controls the chance of a clot (which may benefit some of those who already have the On-X valve implanted I assume) or is it physical changes to the On-X valve itself (which would only benefit new recipients)?

On-X reply: It is further testing with results in two or three years from now.

2. Other than differing valve sizes, does everyone pretty much have the same On-X valve implanted? Or are there newer versions of this since it was first introduced? I can't imagine a new version of an On-X valve comes out very often due to the extensive testing/approvals etc does it? If there is a "latest and greatest" version, I would like to ask my Dr. if he uses it, assuming it has been proven and has some track record of use.

On-X reply: All the implanted On-X valves have the same structure. Only the sizes vary. The sewing rings (part that allows attachment of the valve) vary. We recently introduced an anatomic sewing ring but sewing ring choice is up to the surgeon. It is simply an option for them.
 
My surgeon used the On-x valve with the anatomical sewing ring that just recently got FDA approval a few months ago. I did ask him about this valve beforehand but left it up to his discretion, he said it fit better for me.
 
On-x Valve was my surgeons choice. He came from Virginia where he was in direct charge of an On-x study going on referring to aspirin only being used for on-x patients. He got a job opportunity here in Seattle so he left the study. He said that all indications are that aspirin will be the only medicine needed for us on-x valvers in the near future. It has already been approved in Europe. I don't know if his study is the one that is on-going or not. Hmm think I will ask him that question when I meet up with him on my month checkup. His name is Dr. Glenn Barnhart. After the research I had done on my own coincided with his info I chose the on-x for this reason. Good luck in your quest in choosing a valve.

__________________________________________________________________________________________________________

In the waiting room for 9 years. Bicuspid aortic valve - AVR with an On-x 21 mm valve., Surgery May 23, 2013 at Swedish Hospital, Cherry Hill location, Seattle, WA. Dr. Glenn Barnhart.
 
kimcdougc said:
On-x Valve was my surgeons choice. He came from Virginia where he was in direct charge of an On-x study going on referring to aspirin only being used for on-x patients. He got a job opportunity here in Seattle so he left the study. He said that all indications are that aspirin will be the only medicine needed for us on-x valvers in the near future. It has already been approved in Europe. I don't know if his study is the one that is on-going or not. Hmm think I will ask him that question when I meet up with him on my month checkup. His name is Dr. Glenn Barnhart. After the research I had done on my own coincided with his info I chose the on-x for this reason. Good luck in your quest in choosing a valve.
Click to expand...


There are a few important things to note on this topic, one of which Chaconne pointed out a few posts back. Aspirin only is not an option even being considered right now. The protocol that is being studied/trialed is Aspirin + Plavix...more specifically Aspirin 325 and Plavix 75. Now, one reason this distinction is important is that a pretty significant portion of patients will not have a clinically acceptable response to one or both of those medicines, in fact as much as 1/3 of potential patients, studies have shown. The On-X specific PROACT trials are proving this out with low-risk group patients (Aspirin + Plavix) being transferred to the high-risk group (reduced INR) only after clinical/laboratory evaluation determined unacceptable response to the Aspirin/Plavix protocol.

Now, for the overall majority, this may not be an issue, but it is definitely a potential problem for as much as 1/3 of patients, leaving reduced INR as the only real (potential) future option. One interesting aspect to this, though, is that I think it only takes about a week for the Aspirin/Plavix regimen and clinical evaluation to be done...so perhaps this could even one day be a pre-surgery step in the process when pondering valve selection.

More importantly, though, did this surgeon really say that On-X is approved for aspirin only in Europe? Would he mind sharing more specifics? I certainly don't pretend to know everything about this, but to my knowledge, the Aspirin-Plavix regimen has not been approved anywhere, not even submitted for approval in fact. Enrollment in that PROACT study group was only completed a month ago, so it is well behind the reduced INR portion of the study. For reference, the reduced INR protocol is not approved in Europe yet either...although On-X did submit for that back in the fall, at the same time they submitted to the FDA.
 
TheGymGuy said:
ElectLive, I was about to respond and saw that you took most words out of my mouth.
Click to expand...

Gee I hope not...I usually ramble! :wink2: Of course, you have hit nearly every thread in the forum in the last 24 hours, so perhaps you're right... :thumbup:
 
ElectLive said:
There are a few important things to note on this topic, one of which Chaconne pointed out a few posts back. Aspirin only is not an option even being considered right now. The protocol that is being studied/trialed is Aspirin + Plavix...more specifically Aspirin 325 and Plavix 75. Now, one reason this distinction is important is that a pretty significant portion of patients will not have a clinically acceptable response to one or both of those medicines, in fact as much as 1/3 of potential patients, studies have shown. The On-X specific PROACT trials are proving this out with low-risk group patients (Aspirin + Plavix) being transferred to the high-risk group (reduced INR) only after clinical/laboratory evaluation determined unacceptable response to the Aspirin/Plavix protocol.



Now, for the overall majority, this may not be an issue, but it is definitely a potential problem for as much as 1/3 of patients, leaving reduced INR as the only real (potential) future option. One interesting aspect to this, though, is that I think it only takes about a week for the Aspirin/Plavix regimen and clinical evaluation to be done...so perhaps this could even one day be a pre-surgery step in the process when pondering valve selection.

More importantly, though, did this surgeon really say that On-X is approved for aspirin only in Europe? Would he mind sharing more specifics? I certainly don't pretend to know everything about this, but to my knowledge, the Aspirin-Plavix regimen has not been approved anywhere, not even submitted for approval in fact. Enrollment in that PROACT study group was only completed a month ago, so it is well behind the reduced INR portion of the study. For reference, the reduced INR protocol is not approved in Europe yet either...although On-X did submit for that back in the fall, at the same time they submitted to the FDA.
Click to expand...

Electlive, I only met with Dr. Barnhart once before my surgery. We did not go into much detail about the study I was talking about above. I will on my month visit with him ask for more information and specifics and post here when I get them. Thanks for your take on the situation. I understand only correct information should be posted on this site. Kim
 
kimcdougc said:
Electlive, I only met with Dr. Barnhart once before my surgery. We did not go into much detail about the study I was talking about above. I will on my month visit with him ask for more information and specifics and post here when I get them. Thanks for your take on the situation. I understand only correct information should be posted on this site. Kim
Click to expand...

You know, speaking from my own experience, my top tier surgeon, who I have nothing but high respect for (who is also the boss of the Lead Investigator of PROACT), very much glossed over the details of the On-X study, what actually is known thus far, and what real promise there really is/could be. I wouldn't go so far as to say he painted rainbows or over promised, but he certainly did leave important things unsaid, no mention of potential hiccups either from a time, approval, or patient specific standpoint. I'm not saying that Dr. Barnhart is definitely doing any of this either, but I think it's the nature of surgeons who are short on time, and maybe more importantly not usually in the presence of patients who know enough about any of this for it to matter. I certainly didn't know much when I first met my surgeon, but have learned a lot since my surgery, primarily directly and indirectly through this great place.

Anyway, there's also a possibility Dr. Barnhart could have new and inside information :thumbup: , so I always encourage everyone to share for the benefit of us all....thanks.

This kind of touches on an important issue...the extent to which our medical professionals will educate themselves on very grey areas of risk/benefit and how it influences their decision making. FDA approval will be a very black and white Yes or No, and for some doctors that will be enough, recent history has proven it. But the circumstances of FDA approval will not be clear cut, there will be certain instances when the new protocol makes sense, and equally certain instances when it doesn't make sense. So I think it's pretty important to learn as much as possible about all of this as the evidence continues to develop in order to have informed discussion with doctors when the time does come to make a decision.
 
I didn't mention the details of this in my original post above, but there was a very limited On-X study in Germany about a decade ago that was truly aspirin only. It was halted pretty early on, and never any indication that type of protocol would ever be administered again, due to the risk of adverse events. Well, I happened upon a brief research summary yesterday, though, that actually revealed that some of the patients chose to stay on the protocol...and still are, believe it or not. Anyway, here's what I found: https://www.thieme-connect.com/ejournals/abstract/10.1055/s-0032-1332624.

It's kind of fascinating, actually, a protocol that clearly is clinically too risky for the population at large, and yet in isolated patients can in fact work. I guess the more important question in the future will be if it's possible, and how, to determine ahead of time who the protocol is suited for. Note the requirement of daily phonocardiography surveillance...this is serious stuff. There are some brave test patients out there advancing medical science...
 
It's also possible that there may be a small minority of patients whose systems wouldn't form clots on the valves (or the surgical rings that attach them to our blood vessels). These people would probably not need any anticoagulant - or even aspirin. Attributing this to the On-X valve may be a bit premature. However, it certainly would be great if there was a way to come up with an assessment tool to find those patients who WON'T need an anticoagulant (or who can get by with just low dose aspirin).
 
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