Ask Dr. Z

When a patient has a left heart catheterization, followed by percutaneous intervention, both are considered necessary and can be billed. I'm not sure how to bill services provided when the patient emergently arrives to the hospital and requires this sequence: coronary angiography, percutaneous intervention, and left heart catheterization last. Is the catheterization still billable even though it was done second since there wasn't time to do it prior to the intervention? Or is it not supposed to be billed since it was not done to determine if the intervention should be put in? If not, can I bill for the coronary angiography since that was done prior to the intervention?