she must be suffering from mitral stenosis, for which baloon valvotomy was done. usally it works for 10-15 years only.
then valve gets restenosed.
Now if the valve has only restenosis, balloon valvotomy can be again done.
But if the valve has moderate to mitral regurgitation( that is valve leakge) then open heart surgery and valve replacement is required.
Next Steps
All decision depends up on echo findings, whether there is leakage or not and how much.