> how the highest skilled individuals only step in for the trickiest part of the surgery, but the simpler tasks like getting to a heart are performed by lesser

> how the highest skilled individuals only step in for the trickiest part of the surgery, but the simpler tasks like getting to a heart are performed by lesser doctors or nurses. This is most certainly the case in the US. Most of teaching hospitals have residents do most of the "easy work" such as getting there, have the attending specialist perform the critical part and again have the residents do the rest.