In answer to your question as to why I changed my mind from a mechanical valve to a tissue valve - I'm 63, borderline for either type. Surgeon told me pros/cons of each for my age/lifestyle. I chose tissue because I decided to live a quality life w/o blood thinners. Doc says even if my tissue valve gives out, with new technology coming in, they could do a TAVI, but he thinks if I have any other heart problems, it would not be due to the valve. I like outdoor sports and home restoration. I use a lot of saws in restoration and building things to enhance the home, like planters, trellises, etc. The doc is 58 and active also; said he would chose the tissue for himself. He worries about his mom who is on blood thinner and very forgetful. Choice of blood clot or bleeding to death. I don't like either. I'm very happy with my decision and feel like a burden has been lifted.