Your risk of infection and stroke are both raised for about six months with a graft. Then the risk levels go back to the level they are now, which is only slightly higher than the general population, despite the hype.
You have to remember that the percentage of people who've had endocarditis is skewed when viewing valve recipients as a discrete group. A few reasons for that: a number of people have valve replacement because they had endocarditis, which artificially raises the number to begin with, then there is the higher risk period during healing, and also that one of the biggest risk factors for developing endocarditis is to have had it before.
The six-month expanded risk period is due to the amount of time it takes for epithelium (essentially skin, but internal) to grow over and through the dacron matrix and cover it completely. This creates these risks because healing epithelium can release chemicals that can cause clotting, and is more susceptible to germs.
If someone receives a tissue valve, he or she is placed on Coumadin or Plavix for three months, or for six months with a graft attachment to ameliorate the stroke risk.
Because you're already on Coumadin (warfarin), your stroke risk is not particularly elevated during that time. Your stroke risk will be mostly limited to during and immediately after surgery, while being bridged. However, your endocarditis risk remains high for that six months, and you should avoid bacterially risky behaviors, such as having colonoscopy, intrusive dental work, and skinnydipping in the family septic tank.
Best wishes,
