1.what is the durability of blood vessels used in by-pass surgery? 2.how long you can survive after by-pass surgery?

Depends: What was the condition of the grafted vessel? Did it have plaque in it? Durability also depends on life style and genetics. If your tg and cholesterol are not controlled the grafted vessels will clog. Also, testosterone and Insulin play a role. One other thing is your ability to form collateral circulation to supple the heart. Read about stem cell injections into the vessels.

Should be years: A lower extremity bypass to an above knee location with vein is patent (open) in 70% of people at 3 years and in 60-65% of people when plastic is used as the conduit. Below the knee those numbers for vein and plastic fall to 50% and 15% for vein and plastic respectivelyat 2 years. Survival after bypass surgery depends upon your other medical problems but it is reduced.