Latest about the On-X Valve

[Guest]

J Heart Valve Dis. 2006 Jan;15(1):80-6. Related Articles, Links

The On-X heart valve: mid-term results in a poorly anticoagulated population.

Williams MA, van Riet S.

Provincial Hospital, Port Elizabeth, South Africa. [email protected]

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the clinical performance of the On-X heart valve in a socioeconomically disadvantaged population. Most patients were from an indigenous, poorly educated and geographically dispersed segment of the population where anticoagulation therapy was generally erratic. METHODS: Between 1999 and 2004, a total of 530 valves (242 mitral valves, 104 aortic valves, 92 double valves) was implanted in 438 patients (average age 33 years; range: 3-78 years). The most common reason for surgery was rheumatic valve disease (57%), followed by degenerative valve disease (11%) and infective endocarditis (9%). Follow up was 95% complete for a total of 746 patient-years (pt-yr). Among the patient population, 40% were either not anticoagulated or were unsatisfactorily anticoagulated. RESULTS: Hospital mortality was 2.3%, and none of the hospital deaths was valve-related. Mean (+/- SE) actuarial survival (including hospital deaths) at four years was: AVR 73.8 +/- 8.1%, MVR 83.4 +/- 5.7% and DVR 60.9 +/- 10.3%. Linearized rates (for AVR, MVR and DVR, respectively) for late complications (%/ pt-yr) were: bleeding events 0.6, 1.0, and 2.3; thrombosis 0.0, 0.2, and 0.0; endocarditis 0.6, 1.0, and 2.3; paravalvular leak 0.6, 0.2, and 0.0; systemic embolism 1.1, 1.5, and 3.5. Most systemic emboli were related to infective endocarditis. Among patients there were seven uncomplicated, full-term pregnancies. CONCLUSION: Bearing in mind the erratic anticoagulation coverage and high incidence of infective endocarditis, the results of this study may be regarded as encouraging. The low incidence of valve thrombosis (one case) was noteworthy. These data also suggest that the On-X valve may be implanted with relative safety in women wishing to have children.


Al's Note
This is the kind of study that MAY eventually lead to the On-X valve being used without warfarin.

I wonder if the second author is a distant relative of Betty's husband.

 

[Emma]

LOVE studies like this one!
Thanks for posting it Al!

Love Emma and Chloe
xxx

 

[Guest]

Found Another Article

Found Another Article

J Heart Valve Dis. 2006 Jan;15(1):73-8; discussion 79. Related Articles, Links


North American multicenter experience with the On-X prosthetic heart valve.

McNicholas KW, Ivey TD, Metras J, Szentpetery S, Marra SW, Masters RG, Dilling EW, Slaughter MS, Mack MJ.

Christiana Care Health System, Newark, DE, USA.

BACKGROUND AND AIM OF THE STUDY: This ongoing, longitudinal, multi-center, North American study was designed to evaluate the safety and effectiveness of the On-X valve. METHODS: The On-X valve was implanted in isolated aortic (AVR) and mitral (MVR) valve replacement patients at nine North American centers. Follow up was 98.6% complete. Anticoagulation compliance was evaluated by collection of international normalized ratio (INR) results in all patients throughout their postoperative follow up. Adverse events were recorded according to the AATS/STS guidance criteria. Hematologic studies were conducted postoperatively to evaluate hemodynamics and hemolysis. RESULTS: In total, 142 AVR and 142 MVR implants were performed; the mean follow up was 4.5 years; total follow up was 1,273 patient-years (pt-yr). At implant, the mean patient age was 59.2 years (range: 28 to 85 years); 71.8% of patients who underwent AVR and 33.1% who underwent MVR were males. Preoperatively, 89.4% of AVR patients and 56.3% of MVR patients were in sinus rhythm. The cardiac disease etiology was primarily stenotic, calcific degeneration in AVR and rheumatic or degenerative regurgitation in MVR. Hemolysis represented by postoperative elevation of serum lactate dehydrogenase was very low (median 217 IU after AVR and 251 IU after MVR at one year (82% AVR and 98% MVR of upper normal). Late adverse event rates were low, most notably thromboembolism (0.9%/pt-yr after AVR; 1.6%/pt-yr after MVR) and thrombosis. Kaplan-Meier event-free rates at five years were correspondingly high. Anticoagulation compliance analysis showed only about 40% of INR readings to be within target ranges postoperatively; thus, the control range achieved was much greater than the desired target, as might generally be expected for clinic-controlled INR. CONCLUSION: The On-X valve performed well in this study, confirming the original design intent of minimal hemolysis and low adverse event rates.

 

[Randy & Robyn]

Thank you, Al. Those are great studies to read now that I'm sporting an On-X.

But I won't hold my breath thinking I will be off coumadin someday. Right now, it's enough to know I have a good valve that will keep me alive for a long time.

Randy

 

[SusanC54]

I had posted a message in another thread a few days ago regarding the use of the On-X valve at Mayo Clinic, Rochester, MN. A nurse educator in the cardiology department there had told me that they were starting to use On-X valves which I was very excited to hear. However........I recently spoke to a Physicians Assistant in the cardiac surgery department who spoke to the surgeons and they are NOT using the On-X valve. This was a bit disappointing to me, and I know a member recently convinced the Cleveland Clinic to use an On-X for his surgery. Any ideas on how to introduce a new valve to your surgeon? I'm sure there are all kinds of politics and so forth associated with this.......any input would be greatly appreciated!

Susan

 

[Randy & Robyn]

Susan,

I happen to be the person who received the first On-X at Cleveland Clinic. The best place to start is with the chief of cardiovascular surgery. At Mayo in Rochester that would be a Dr. Schaff. I actually have spoken to him since I had my first surgery performed at Mayo last fall and was considering going back there. He was very receptive and did agree to make arrangements for me to have the On-X should I return to Mayo for my second surgery. However, due to insurance reasons I went to Cleveland instead.

Dr. Schaff's take on the On-X was that it was a good valve but that more time was needed before any definitive conclusions could be made concerning its superiority.

If I were you, I would call his office and ask to speak with him. Tell him you feel strongly about having the On-X used in your case. Feel free to use my name as I'm sure he remembers me. If he agreed to use the On-X with me, he should certainly give anyone else the same opportunity.

If you wish, I can also put you in direct contact with a nurse at MCRI, the manufacturer of the On-X, who helped me. She knows Dr. Schaff's nurse very well and would be happy to help you out. Just let me know.

Good luck.

Randy

I had posted a message in another thread a few days ago regarding the use of the On-X valve at Mayo Clinic, Rochester, MN. A nurse educator in the cardiology department there had told me that they were starting to use On-X valves which I was very excited to hear. However........I recently spoke to a Physicians Assistant in the cardiac surgery department who spoke to the surgeons and they are NOT using the On-X valve. This was a bit disappointing to me, and I know a member recently convinced the Cleveland Clinic to use an On-X for his surgery. Any ideas on how to introduce a new valve to your surgeon? I'm sure there are all kinds of politics and so forth associated with this.......any input would be greatly appreciated!

Susan

 

[SusanC54]

Thanks for the information, Randy. I think I will probably follow up with Dr. Schaff......I was kind of discouraged last week when I talked to the PA there who seemed to have very little knowledge of what the On-X valve was. I need to do somemore research on the issue, but the On-X seems to definitely worth pursuing. How did you feel about being the first patient for the Cleveland Clinic?

Susan

 

[Randy & Robyn]

How did you feel about being the first patient for the Cleveland Clinic?

I was very comfortable with it. My surgeon had done research on the On-X after my request to him. He felt it was a great choice. All prosthetic valves are very similar when it comes to implanting them. There was also a representative from MCRI present to assist in case any questions arose.

Randy

 

[SusanC54]

Thanks for the response, Randy. I got an e-mail from a Catheran Burnett at MCRI today. She's apparently the nurse manager with them and she told me that the clinic has been considering On-X.....I wonder if she's talking about their Scottsdale or Jacksonville locations.

What do you think about having both MVR and AVR with On-X? I had rheumatic fever as a child and I need both valves at this point. I know the MVR requires more anti-coagulation, so I'm wondering if it's worth it for me to press the On-X issue with the clinic or just go with the St. Judes......too many decisions!

Thanks for your words of support!

Susan

 

[Randy & Robyn]

Catheran was my primary contact at MCRI as well. She was at Cleveland Clinic during my surgery. I can assure you she will do whatever she can to help you out.

I'm not a surgeon and certainly do not want to give you advice in that regard. I can give you my opinion. As you are aware, the On-X is undergoing FDA trials for reduced anticoagulation. You are correct that the mitral valve requires more anticoagulation. However, if the trial works out, your target range would be 2.0 - 2.5 as opposed to the present standard of 2.5 - 3.5. That is a big 'if' at this point though.

And just how much of a difference will the reduction in range make concerning safety and reduced bleeding incidents? I can't really say. I haven't been on coumadin long enough to even know whether such a narrow range can be held. I have heard from others on this site that a 0.5 range is impossible to maintain. In that case you would still have fluctuations above and below those numbers.

I can say that I believe the On-X to have advantages and the potential for fewer adverse events. But I also believe the St. Jude is an incredibly durable and safe valve as well.

It truly is a very personal decision. I hope that helps, Susan.

Randy

Thanks for the response, Randy. I got an e-mail from a Catheran Burnett at MCRI today. She's apparently the nurse manager with them and she told me that the clinic has been considering On-X.....I wonder if she's talking about their Scottsdale or Jacksonville locations.

What do you think about having both MVR and AVR with On-X? I had rheumatic fever as a child and I need both valves at this point. I know the MVR requires more anti-coagulation, so I'm wondering if it's worth it for me to press the On-X issue with the clinic or just go with the St. Judes......too many decisions!

Thanks for your words of support!

Susan

 

[Guest]

From my experience of personally seeing over 35,000 patient visits to monitor warfarin, the lowering of the warfarin range from a top of 3.5 to a top of 3.0 will make absolutely no difference whatsoever. I have found that there is very little increase in the risk of bleeding as long as the INR is below 5.0. There is only a minimally increased risk with INRs between 5.0 and 8.0. Even INRs above 8 don't produce much higher risks of bleeding if you have the INR monitored about every 4 to 6 weeks.

Using an analogy to put this in perspective, consider this. You have to drive all day on city streets with a speed limit of 35. Will you be more likely to arrive safely if you try to keep your speed under 40, or will you arrive more safely if you try to keep your speed between 25 and 30. My feeling is that you cannot determine the answer. There are so many other things that could go wrong that the small difference in the speed will be such a small factor as to make almost no difference.

If you are the type of person who would worry all night every night for a week before making such a trip, then go with the ON-X valve. If you are the type of person who thinks that you can't tell the difference then make your choice of valve based on other factors.

Please don't think that I am steering you away from (or toward) any certain valve. I have no interest in this other than to help people put things in perspective.

 

[aussigal]

hey guys and gals...I have only recently decided to have a look at other brands of valves...and I dont even know if the On-X is available here in Aus....

But I am curious after reading their site...

Do you think their claims that it is made of a superior material makes any difference...I kinda also liked the idea it seems to be designed by a very good engineer ...

also I have read of it being a quieter valve...this is also of interest to me as I am the kind of person who runs around at night to turn off dripping taps etc... ...

I have begun to wonder if the tried and true St Jude might be too noisy for me to sleep with ...

 

[Guest]

They have always said that the carbon surface that they use makes for a "slicker" surface so that blood does not stick to it and clot. Whether or not that makes much difference, I'm not sure. My impression is that the problem with valves is the way that they open. Think of a door opening. The space between the door and the wall holding the hinges is dead space. In a natural valve, the squeezing motion of the wall and the fact that the leaflets are not flat cleans this area out very efficiently. (Evidently so do pig and cow valves.) However with a metal valve that is flat and the wall of the heart becoming fairly rigid after the valve is sewn in, then there is dad space between the leaflet and the wall of the heart where blood can stagnate and form a clot. Warfarin prevents clots in stagnant blood, not fast flowing blood. So it looks like the On-X slicker surface may allow this dead-space blood to move out better but whether or not that is true remains to be seen. The studies need a lot of people being observed for many years before this can be determined.

For example with the drug Exanta the tests with hundreds of people showed that it was a good drug. But there was a problem that only showed up at the rate of about 1 in 3,000. The tests with hundreds of people could not detect this. But if 1 million people would have been put on the drug and 1 in 3,000 died then there would have been 333 deaths. This is why I say that they need a lot of people over a long period of time to detect this.

 

[Randy & Robyn]

From my experience of personally seeing over 35,000 patient visits to monitor warfarin, the lowering of the warfarin range from a top of 3.5 to a top of 3.0 will make absolutely no difference whatsoever. I have found that there is very little increase in the risk of bleeding as long as the INR is below 5.0. There is only a minimally increased risk with INRs between 5.0 and 8.0. Even INRs above 8 don't produce much higher risks of bleeding if you have the INR monitored about every 4 to 6 weeks.

Using an analogy to put this in perspective, consider this. You have to drive all day on city streets with a speed limit of 35. Will you be more likely to arrive safely if you try to keep your speed under 40, or will you arrive more safely if you try to keep your speed between 25 and 30. My feeling is that you cannot determine the answer. There are so many other things that could go wrong that the small difference in the speed will be such a small factor as to make almost no difference.

That is a very interesting and informative analogy, Al. It definitely helps to put the bleeding risks in perspective.

hey guys and gals...I have only recently decided to have a look at other brands of valves...and I dont even know if the On-X is available here in Aus....

But I am curious after reading their site...

Do you think their claims that it is made of a superior material makes any difference...I kinda also liked the idea it seems to be designed by a very good engineer ...

also I have read of it being a quieter valve...this is also of interest to me as I am the kind of person who runs around at night to turn off dripping taps etc... ...

I have begun to wonder if the tried and true St Jude might be too noisy for me to sleep with

I think a definitive answer concerning the superiority of the On-X is still forthcoming and will be based on how the On-X performs in the reduced anticoagulation trial. But many of the studies so far certainly seem to suggest a reduction in adverse event rates for the On-X. Here is a link to another favorable study: http://icvts.ctsnetjournals.org/cgi/rapidpdf/icvts.2005.114843v1.pdf

As for noise, it has been a very quiet valve for me. I only notice it in very small, quiet rooms and even then it is just a barely audible ticking. Others on this forum say they cannot hear it at all. However, I have talked with a couple of people who say it is loud enough to be bothersome at times for them. Once again, it seems that some people's bodies absorb sound better than others and it is hard to predict what your personal acoustics will be like.

Randy

 

[Guest]

For people with atrial fibrillation (without mechanical vavles) the noise is louder if they are on their left side with the ear on a pillow. Test this with your valves.

 

[SusanC54]

Randy & Al,

thanks so much for all the information on the INR issues, etc. It has really helped me! Along with your input and my discussion with my friends here in Rochester who actually work with a lot of the cardiac surgeons (the advantage of living in this community where almost everyone is either employed by the Mayo Clinic or IBM), I think I'm ready to make another appointment with the surgeon to discuss all of the valve selection issues.

I really appreciate your time and attention!

Susan

 

[Guest]

Best of luck.

Olmstead County must be the most health-surveyed place in the world.

 

[aussigal]

Thanks for your input Al, Randy and Robin...

I havent decided if I am brave enough to be different and ask for an Onx yet ...I think I shall do a bit more reading and see what I come up with...

 

[Dustin]

The on-x is going strong, but I wouldn't count on a non-warfarin oral therapy just yet. If we can get the same low rates of valve thrombosis by 2015, then the statistics are much more reliable. Nonetheless, knowing that the on-x shows signs of thrombo-resistance could give the McValvers a better night's sleep when their INR is all over the place. I'm cautiously optimistic and would choose an on-x but only with regular warfarin therapy.

 

[aussigal]

Thanks for your insight Dustin...

If I chose an Onx it would be for the idea of it offering this reduced thrombosis and that sort of stuff (the stuff that is already showing to be great about it!)...it would not be because it may in the future not require warfarin-therapy (although that would be a nice bonus!)...

Thats why I am wondering if it is of value to even consider it for myself ....

OR
.... do I not worry about it and go for the old fave St Jude.... sit back and watch the studies for 10 or more years and be ready to recommend it to my kids if all works well for this valve and they need AVR's in the distant future...