Looking for some guidance from the experienced coders who also deal with compliance and insurance contracts. We started having an issue with our Blue Cross (Nebraska) on denying venograms with intravascular ultrasound and placement of stents (CPTs 36012, 37252, 37253, and 37238) as experimental and investigational. Typically the IVUS is showing 80-100% blockage which is why the stents are being placed.The issue we have is none of these procedure codes are on the precert list, on the pre-determination list, nor do they have any medical policies on their website. The provider rep and medical director at BC refuse to give us the information that they are using to make their medical necessity decision. Any advice on what to do? Surgeon bills are over $20K and hospital bills are $120K+. They are refusing payment on all of it with no explanation other than does not meet criteria.