There is a way to do a CABG without going on cardiopulmonary bypass (CPB) and arresting the heart. It’s called Off-Pump Coronary Artery Bypass Grafting, or OPCABG. How do they do it? Why do they do it? Well, the why is easy. CPB has a lot of downsides to it, including risks from cannulating and risks from the CPB pump itself, and so if you can avoid it, you avoid those risks. However, not every patient is suitable for OPCABG, so the CPB isn’t going away just yet.
How do they do it? Surgeons use a special stabilizer device to hold the heart in place, allowing it to continue beating while the part where the surgeon is working is held still and stable. I assume that it is much easier to suture on something that isn’t moving! (After spending a semester in school first-assisting in cardiac surgery, I’m not sure I could suture coronary arteries on a heart that was perfectly still, much less one that was beating!)
In this great Instagram post, Dr Rishi Kumar not only explains this process in more detail, but shows you a great video of the process itself.