Second opinons

I had by- pass surgery 9 years ago and recently was having chest pain . I went and had a stress that led to a cardiac cath . and found a new blockage in the bottom of the heart . The surgeon I saw after his reveiw thought it not serious enough to operate and to treat it with drugs and exersize . Is it true thet they only can go thru the centerof the chest for bypass twice   ?  And should I seek another opinon what he said and how he explained it made sense . But what about long term ??? Thank You