Ask Dr. Z

"During the CABG procedure, our provider encountered a heavily diseased ramus. Separate and extensive endarterectomy was performed. Unfortunately, this was not suitable for bypass, so the artery was ligated at its mid aspect. The distal location of the artery appeared to be appropriate, so a longitudinal arteriotomy was once again performed. There was once again near complete obliteration of the lumen of the artery due to chronic disease. The distal aspect of the ramus intermedius was ligated."  What is the appropriate coding for this scenario? Do we bill for the failed endarterectomy or just the ligation? Or something else?