Ask Dr. Z

I am hoping you can help with the following case. I don't believe that code 35879 should be billed at the same time as code 35566, but I am considering the use of a -22 modifier. "Once femoroperoneal bypass was completed, ultrasound Doppler was used to evaluate graft, and the graft was found to have relatively low velocities of 15cm/sec in the thigh. There was a significant flow difference noted with velocities of 80 cm/sec in comparison to adjacent velocities of 15cm/sec. Incision was made over the graft, graft was mobilized, and it was decided to proceed with patch angioplasty since abnormality was likely a frozen valve. A segment of residual GSV was harvested and opened longitudinally for patch purposes. Arteriotomy was made through the valve and fibrotic tissue debrided away from the wall. Standard onlay vein patch angioplasty was then performed. Repair was complete, flow restored, and duplex showed no abnormalities with significantly improved velocities. Total procedure time was 7 hours."