A very good friend of mine went in for heart valve surgery when he was 73. The valve was damaged from polio he had as a child.
About 2 weeks later he called me and said he was doing great, could breathe better, had better stamina, and felt like a new man. He died the next day. His wife told that after he called me he told his wife he was tired and was going to take a nap. The next day she tried to get him to go to the doctor but he said he was fine, just tired.
My point is even in the best of care, heart surgery, or any surgery really is very serious and the outcome is not guarenteed.
Or China.