Hi Karen:
Welcome. You might want to copy your post and re-post it as a new thread in the Valve Selection forum. Otherwise your question might not get the attention it deserves.
You will find that people here have some pretty strong opinions about valve choice. It is probably worthwhile to spend some time reading old threads in the Valve Selection forum, particularly:
http://valvereplacement.com/forums/showthread.php?t=14330
I try to stay out of discussions about valve choice as I have yet to have a replacement myself and haven't arrived at a decision about which I'll have when the time comes. I will say that when considering the effect warfarin will have on one's life, I believe the single most important factor to consider is not so much the ramifications of the drug's effect on one's blood's coagulation as the misconceptions surrounding those ramifications that abound in the medical community. In other words, it may hold little importance that it is safe to have a colonoscopy while on warfarin if the doctor performing the procedure
thinks it is unsafe and takes you off it for five days, putting you at serious risk for a stroke. If you decide to go mechanical and take warfarin you must be committed to regular administration of the drug, testing of its level in your blood and to advocating for yourself in the face of dosing relative to fluctuations and future procedures. The vast majority of warfarin users on this website are quite comfortable with this.
On the flip side of this coin, I wonder why you have been advised that you'll get only 14 years out of a tissue valve when you got 14 out of a homograph. As a general rule, one's body chemistry is harder on valves when one is younger. That, combined with the increased longevity that is expected from today's valves, would, I suspect, give you a better prognosis than 14 years. I admit I don't know much about homographs though.