Dear jerry,
True on both counts and some doctors would agree with you. The problem with doing a heart cath on everyone is that it is an invasive procedure and is associated with risk (albeit low) of complications. Thus you would not want to expose someone in whom there was a low chance of finding coronary artery disease to a potentially dangerous test when there are safer alternatives. In the final analysis it comes down to the clinical judgement of the doctor. If he/she feels there is a high likelihood of finding coronary artery disease he/she may go directly to a heart cath. If on the other hand the likelihood of coronary disease is lower then a non-invasive test may be the first choice.
regards
browser2