Diastolic dysfunction can become as serious as any form of heart failure. It is essential that your father see his heart doctor on a regular basis to assure optimal treatment of his diastolic dysfunction.
The decision to repair vs replace the mitral valve depends on the cause of the valve problem and the likelihood that the mitral valve can be successfully repaired. For example, patients with the most common forms of mitral valve problems can usually be successfully repaired. However, mitral valve problems caused by rheumatic fever may not be repairable and may require valve replacement.
My philosophy is to repair the mitral valve whenever possible. This can be accomplished in greater than 90% of patients with the most common form of mitral valve problems and in greater than 70% of patients with more complex forms of mitral valve problems.