Hi. I'm Dr. Gotthelf. I have been a vet for 35 years and I would like to use my experience to help you with your pet's medical problem.
Probably the best way to know how the new pup is going to do is to contact the breeder and ask for a list of people that they have sold puppies to in the last several years. Call, write, or e-mail them and ask if there have been any serious medical problems. Obviously, you will not be able to definitively make a 100% call on whether your new puppy will ever have problems, but if there is something in their breeding lines, you should be able to identify it by talking to owners of their pups.