I called Colorado University and spoke to some one in the vascular area and asked if he was retired. I got this answer:

Dr. Brantigan STILL has full privileges at Pres/ST Lukes and St Joe's and CU. He merged his practice with the vascular service at the university. His nurse Kristen is now the nurse practitioner on the service at CU and his ultrasound tech that worked at his office (Shawn) is in charge of the vascular lab for the institution and Tera (his surgical scheduler) is the patient care coordinator for the CU vascular lab doctors. The plan is for Dr. Brantigan to train the new faculty members and create a dedicated TOS program/clinic.

So glad he isn't retired! That would be a huge loss!