Thanks for clearing that up Dan.
I have an On-X, nice to know that the new IFU could be 1.5 - 2.0.
I'd use that as a safety factor personally, as I'd really feel more comfortable with my INR around 2.5
I don't buy into the the line we valvers hear so often, that your mechanical valve will last your life time.
In some cases they may, but there are many others here, including myself that required a re-op due to Pannus, or some other condition that promoted the re-op. Hopefully, the On-X design helps fight off pannus growth. That was my main reason for selecting it.