I've been home for a few days with a 29mm tissue valve. I was surprised to find that I hear it at night as well. I've been told that as my left ventricle shrinks back to a normal size, and the heart settles in, that the sound should go pretty much away.
If any of you have an iphone, i found an app last night called Sleep Pillow. It's awesome!! I never was one to have noises in the room during sleep, but I would have still gotten this a long time ago if id known about it! You can set it to play 100s of noises from raining, wind, ocean waves, fireplace crackling, and my latest personal favorite, the sound of rain hitting a tent! It's really great and all of you need to check it out. If you don't have an iphone, there's plenty of these apps out there. They're usually listed as white noise apps, although I still don't know what white noise actually is.
Later.