What is best method for replacing aortic valve damaged due to rheumatic heart disease for 51 year old man?mechanical biological or auto or homograft?

Depends: this is a question for an experienced cardiac valve surgeon. But in general it depends on over-all condition of heart, if you have any other valve problems, size of aortic root, ejection fraction, age and over-all health. Please consult a cardiothoracic surgeon for best advice.

Aortic valve: If the original valve cannot be surgically repaired either a mechanical, pig or cadaver valve may be used,

Longevity: Repair is the best option but may not be feasible. The tissue valve options are attractive because of minimal anti coagulation but at 51 you would have to plan on at least one reoperation in the future. Mechanical should last a lifetime but will require anti coagulation that may inhibit some of your activities. Discuss in depth with surgeon and cardiologist.