It is dangerous, but it is probably more dangerous to do nothing. I had a triple bypass earlier this year. The information I was given was before I signed the consent form indicated about two percent of patients did not survive the surgery. To some people 2% may sound like a small number, but when you are about to have the surgery it sounds pretty big. One thing that made me feel a lot better was a talk with a nurse. She pointed out that 2% was an average, including people who were rushed straight from the emergency room to the operating room following a massive heart attack, people who were a lot older than I am, and people who had other complications such as diabetes, emphysema, etc. So, while there is no doubt that the procedure is more dangerous than most other surgeries, the odds are much higher that everything will come out well.