Hello,
I was recently diagnosed with BAV, am 33 and am stil thinking about the choice of Ross versus mechanical valve.
Are the different mechanical valve's (St Jude's Regents, ATS or OnX) diffferent i ntheir tendency to produce bloodclots given the same INR?
I.e. are there any studies who have actually evaluated this?
I thought that given that the OnX valve has now been approved for use with an INR of 1.5-2 in Europe, it must generate less bloodclots (thrombosis) then the others.
Is that assumption correct?
[Why else would be they be able to market this with lower INR?]
Any feedback on this would be very useful.
thank you
tommyboy
I personally believe the most used mech valves today, are pretty close, as far as the chances of clots, so need anticoagulation that increases your chance of bleeds, or if one was clearly better everyone would use that. so far they don't. Luckily most people are very happy with THEIR valve and believe theirs is the best mech or best tissue and for them it is.
I think the only way to get a small idea of "which" valve clots the least, and it of course wont be exact, is read several studies on the individual valves, but there isnt much info..like what their INR were at time of "events' or what other problems did the patient have or who home tested etc. or even the patients age, since it is pretty well known the people who do worse on Coumadin are the elderly, (which most studies classify elderly as 60 and up ish) for several reasons, beside the increased chances of other medical problems, they are often, -NOT always a little frailer, bones are often weaker, skin thinner, tend to fall from standing, more than younger people ..... So it would help to know the ages who had the clots or bleeds and who didnt, of course since everyone who chooses a mechanical valve does it hoping to live a very long happy life w/ less risks of a REDO so, the majority of people with mechanical valves placed when they are young, will one day be "elderly on Coumadin"
. You could go to pubmed and type in the different valves and see what comes up some MAY compare various valves, but you have to pay attention to the year of the study and which valve they are talking about for the companies like SJM and Edwards, who have been making valves a long time and made several different valves. Also the most current information most likely will be hard to find any good information about, since the trials and studies, are still going on and they havent been written up yet. The best way to learn the most up to date information on the trials and studies going on is the various articles or webcasts available from the different doctors conferences, Cardiology, Heart surgeon valve from the US and everywhere else.
But when you read the different studies, you have to pay attention to what they say or dont say, depending on who is running the trials, for example there is a On-x study from early 2000s showing how well they did in poorly anticoagulated patients in South Africa.
http://www.ncbi.nlm.nih.gov/pubmed/16480016 where 40% were either not anticoagulated or were unsatisfactorily anticoagulated., I'm Not sure what unsatifactory was, maybe a few low INRs? anyway so 60%
were satisfactorily anticoagulated.
This study was one of the main reasons they were able to start the low INR trials.
BUT 2 years previously the same author (with a couple others) from the same hospital did a study on 3 valves, with about 500 patients,
http://www.ncbi.nlm.nih.gov/pubmed/15383051 "A comparison of mechanical valve performance in a poorly anticoagulated community".Carbomedics, Medtronic Hall and On-X , that showed "There were no significant differences in the performance of the three valves in the aortic position. In the mitral position the linearized rate of valve thrombosis was significantly higher in the Carbomedics group (p = 0.002)"
But what "I" personally found interesting, was of the 3 valves, the percentage of patients who were NOT "adequately anticoagulated" was much higher for the Carbomedics and Medtronic hall ( both about 60%) than the ON-X (about 40%)
the Carbomedics group 140 valves were implanted in 126 patients (aortic 30, mitral 82, and aortic and mitral 14), 39% were adequately anticoagulated, Medtronic Hall series 224 valves were implanted in 198 patients (aortic 50, mitral 122, and aortic and mitral 26), 39% were adequately anticoagulated On-X series 252 valves were implanted in 200 patients (aortic 44, mitral 104, and aortic and mitral 52), 58% were adequately anticoagulated. Follow-up was 94% complete for a total of 2217 patient-years.
Would that make a difference? I don't know for sure, but My GUESS would be it might have shown better results for the first 2 and slightly worse for the ON-X if they were equally or more closely anticoagulated the same percentage of time..
BUT as far as the
are there any studies who have actually evaluated this?
I thought that given that the OnX valve has now been approved for use with an INR of 1.5-2 in Europe, it must generate less bloodclots (thrombosis) then the others.
Is that assumption correct?
[Why else would be they be able to market this with lower INR?
I guess it is all relative, but there was an interesting thread on what the PROACT trials (so far) showed and didnt show
http://www.valvereplacement.org/for...mark-and-(unfortunately)-1-5&highlight=PROACT ON-X claims there were the same amount of total events which is true, BUT the lower INR had more clots and higher (normal) INR people had more bleeds.
The High risk group (started w/ 435 total) after the first 3 months when everyone was on 2-3, about 60 people were removed, for various reasons, from not getting a ON-X valve, to death (8) adverse Event (10) or patient stopped,....during that 3 months. so the remaining 375 were broken down 185 in lower inr 1.5-2 and 190 Control 2-3 INR and followed for about 4 years at the time the intermediate results were reported, a mean of about 2 1/2 years. which is important to remember when reading how many people have major bleeds, clots strokes, in that time frame. When you see that of the 190 patients in the control 13 had major bleeds compared to 8 of 185 test patients had major bleeds, or in the lower INR there were 4 CVA (stroke) and 5 TIA compared to only 1 CVA and 2 TIAs in the controls normal 2.0-3 INR group. Whic IMO looks alot like the old saying, more clots but less bleeds at lower INR and higher bleeds but less clots at the higher INR.
Of course this doesnt count the events that happened in the first 3 months, before they were randomized into the 2 groups.
As far as target range for INRs, many people who are given a range, try to stay in the middle of the range feeling that is the "safest" (NOT safe) or the sweet spots where you lower the chance of clots but dont raise the chance of bleed, altho some people rather stay at the lower end or higher end. which is probably why some reccomend a single number as the target., it was rather common a few years ago here for many of the members to prefer to stay at the higher end, w/ the saying they feared clots strokes , more than bleeds, and "you can replace blood cells but not brain cells" . Altho many doctors prefered lower end since the main bleed they worry about is internal bleeds and hemorrhagic stroke, which is usually more devastating than strokes caused by a clot.
FWIW the reason I said "safest' and not safe, was even w/ home testing and the newest best valves, people STILL have problems w/ clots or major bleeds, being in range lessens them, but their still are at least 1-2% of people having bleeds or clots each year, like the PROACT results show.
ps You asked about Homograft earlier, some of the reasons they arent used much any more, is for the last couple generations of tissue valves, they were lasting as long or longer than Homografts, plus they are harder to get since people have to donate them when they die, also the initial surgery or REDO is a little more complicated than other tissue valves
http://my.clevelandclinic.org/heart/disorders/valve/youngvalve.aspx discusses the various valves
