Hi Dodgy, i dont think you should have second thoughts about the valves in your case; i have access to about 12 doctors in my family, and they all agree that the Mitral Val and tissue is not such a good match; unless you are ok with repeated procedures over time, regardless of what you may hear, a tissue valve has a life spam for sure; i also had the same dilemma and at times when worry about warfarin tell myself "ah, made a mistake". but the truth is, that i was 63 when got the mech valve, and was told to prepare por a second op around 78, really ?, nah, not for me; get it done once and over; loosing some weight was important for me, the cardiologist told me "even when you are sleeping" your hearts works harder if you are over weight, i did what i could, not we all can do, and changed my eating life, it was very hard for my tastes, but i lost 45 pounds, and that made a difference, all i want is not ever go back for surgery, last words my excelent surgeon told me on discharge day were "You Dont Want to See Me Again".... when i said "hope to see you again" , guess i said the wrong thing while trying to say thank you, but i dont forget what he said...., also told me 5 times "you must must must must must take antibiotics before you see a dentist", HOPE all goes well with you, keep in the loop, lots of good people here with the intention of support,