If your leakage is well tolerated by your body, i.e. the heart wall thickness remain stable and don't increase, then you should be declared fit.
Furthermore, in FAA & JAA medical requirements, there are clear paragraphs on how to re-qualify after valve surgery. I know of a case very close to me where the pilot had aortic valve replacement - twice - and always got a Class I medical back (after 6 month compulsory waiting period).