The alternative to coronary bypass surgery is placement of stents, if you are a candidate. Whether you are a candidate for stents depends upon a number of factors, including the location(s) and size of your blockage(s). A good cardiologist should be able to explain all your options to you, including why you are or are not a candidate for stents. Often, a cardiologist will specialize in placing stents, while another specializes in doing bypass surgery, so you may want/need to see more than one cardiologist. Some people also choose to try to control the problem with diet, exercise, and medication, but again much depends upon where the blockages are, how many, how much damage was done to your heart, etc.
Hang in there!!