Sometimes patients have blockages in their arteries that are calcified and hard. If the arterial plaque that is causing the blockage is too hard for the angioplasty balloon to crush, we may recommend rotational atherectomy. Most such procedures utilize the rotablator, a small drill with a burr on the end coated in diamond dust. The rotablator drills through the calcified plaque, breaking it up into tiny pieces without damaging the artery walls. These pieces of plaque can then be safely picked up by your bloodstream and carried away, and eventually your body processes and eliminates the pieces of plaque.

You can see more on page 10 https://www.mountsinai.org/files/MSHealth/Assets/HS/Care/Heart/StructuralHeart/MtSinai_PatientGuide.pdf

Credits- Mount Sinai 

Reference- Rotational Atherectomy. (n.d.). Retrieved from https://www.mountsinai.org/care/heart/services/coronary-disease/treatment/rotational-atherectomy