Question: What is the difference between on-pump and off-pump bypass?
Answer: The traditional way to do a bypass operation is to use the heart-lung machine, or cardio-pulmonary bypass. If we use the heart-lung machine, the machine itself does the work of the heart and we can actually stop the heart while we work on it. We don't take the heart out of the chest; we work on the heart inside the chest, but it's stopped and it's a quiet, bloodless field. And so we can see very precisely what we're doing. That's the most comfortable way for the surgeon to do the operation.
Now recently, techniques and technologies have been developed to allow us to do the operation without using the heart-lung machine. And that's called off-pump bypass surgery. And those are stabilizing devices and such that allow us to isolate one segment of the artery at a time to do the anastomoses; and off-pump surgery, in some instances, can be preferable to on-pump surgery.