Coding Right and Left Carotid Stents at Different Operative Sessions

Question:

The physician staged a patient’s bilateral carotid stent with embolic protection procedures. The right carotid stent was done first and then the 6 weeks later the left side was done. What is the correct modifier on the second carotid stent?

Answer:

The second carotid stent, although staged clinically, is an unrelated procedure performed during the global period. Append a modifier 79 to code 37215 to indicate this unrelated procedure. Even though these are the same procedure reported with the same CPT code, they are performed at different anatomic locations and therefore are unrelated.