A surgeon did reconstruction of the pericardium after coronary artery bypass surgery. The dictation reads: "Because of the patient's young age and the right internal mammary artery crossing the midline I did reconstruct the pericardium with Core Matrix acellular xenograft using a running 4-0 Prolene." A representative from Core Matrix says I should bill add on code 15777 for this but the CPT descriptor says it is for soft tissue reinforcement (e.g. breast, trunk) so I don't think this is the right usage for this code. Can anyone out there give me some advice, please? Thank you!