They can amazing things with heart surgery these days. As long as she is strong enough to handle it everything should be fine.
I just found out my oldest sister is going to have her gall bladder removed on June 6th. This worries me cuz she's around 350 pounds. I'm not sure her heart will take the anesthesia. So - kinda scared......... Its tough when our loved ones are facing surgery.
Prayers for MIL and all the family.