Darla,
I have been thru 3 surgeries, the last one after endocarditis was treated. My mechanical aortic was leaking where it had been placed 8.5 yrs before. My mitral was leaking severely from the attack of the bacteria. To answer your ?, I have found that after surgery, a tiny leak is usually detected, but the surgeon and cardio are never worried about it.
I agree that it's so important to get the best surgeon. My surgeon moved my aortic valve up along the aorta, to avoid the formerly infected tissue around the mechanical ring, and it's good that he had the experience to think of doing this and then do it. I recovered fast from my 3rd surgery. Try not to worry. At least having had 2 surgeries, you know more of what to expect! Of course, each time something else might come up, but I found I was ready for anything, and so willing to get better, walk the hospital halls to feel better.
I hardly coughed at all this last surgery. That made a huge difference. Maybe the 4 chest tubes made the difference in drainage, so less coughing? All the best to you!+