Does anyone know if you can use a PA as the interventionalist at an extension of practice?

Wondering if the MD has to be present at the facility when the procedure is being performed, like a dialysis visit in the hospital when the pt is on the machine.

I’ve seen other units use PA’s in this fashion with the PA being the person completing the entire procedure but there is always an MD on the premises.

Lastly, if the procedure can be billed under the PA do you only get 80% from CMS?

Thanks in advance.