system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do doctors perform bypass surgeries instead of removing plaque from the patient’s arteries?

Seems to me like it would be simpler to restore blood flow by removing the blockage instead of just putting a path around it? Or am I misunderstanding how bypass surgery works?
gpt
Sometimes the blockages are too large to open with a balloon or stent. Or sometimes they can’t wire the balloon or stent through a thick or complete blockage. Also if there are multiple blockages that make it too dangerous they may opt for the surgery. Or if a patient is very unstable. Occasionally the angio can become complicated (the vessel can be perforated) and surgery is a more controlled environment. 

I used to be a nurse in the cardiac angio lab. Fun times!