Ask Dr. Z

I'm billing the following to Medicare: 36903, 37186, and 76937-26. Medicare denied code 37186 because its "parent" code was not billed with it; however, the provider did it after the initial angio of the HeRO showed thrombus and the end result was a placement of a stent within the AVG, which justified the 36903 coding. Code 76937-26 was also denied, but the claim didn't identify the AVG site as failing, I'm sure I could add that info, but I don't understand the Medicare denial of 37186... do they bundle it all with code 36903? The secondary commercial plan's claim checker allowed all 3 lines, but when it crossed to them they denied it as failure to follow the primary payer rules. How should mechanical thrombectomy be coded when done with codes from the dialysis circuit?