STANDARD OF CARE ; INDICATIONS FOR A CORONARY ANGIOGRAM

Last Monday, we wrote about the problem of chest pains., and how they can be sorted out at the outpatients clinic level. As stated in last week's discussion, there can be many causes for chest pains and it is always, the cardiac variety that should give cause for alarm and urgency. Also that cardiac causes for chest pains, can usually be demonstrated by the presence of inducible ischemia, like on the stress ECG.
Very often, the defining test is the stress ECG, and not as some quarters will wrongly propagate, the MSCT ( multi-slice CT scan ) or a newer version, the multi-detector CCTA. As we have stated in many discussions, the MSCT and MD-CCTA, sees artery outline, from computer reconstruction, which seem to indicate stenosis, where there may be non, or seem to indicate severe blockages, when there are only minor blockages. But, if the MSCT or MD-CCTA shows a normal artery, it is likely to be a normal artery. That is why the MSCT or MD-CCTA should ( as used by the Americans ) be used to exclude disease.
Coming back to today's discussion, the indications for a coronary angiogram, must include significant anginal type chest pains, together with inducible ischemia on stress testing, or other forms of functional testing, either, or both. Some cardiologist may modify further by saying that in the elderly, chest pains, uncontrolled by medications, would require investigations with the coronary angiogram. In the young ( those below70years ), the threshold for doing an angiogram is lower, and for those above 70 years, the threshold to do an angiogram is higher, meaning that we do not simple do coronary angiograms "for bread".
The presence of inducible ischemia, either by way of symptomatic chest pains or assymptomatic positive stress ECG is important, because, a positive coronary angiogram may lead on to coronary angioplasty, and we really must not angioplasty or treat stenosis that are not clinically important. We define a clinically important stenosis as one that causes significant myocardial ischemia, as evidence by chest pains or a positive stress ECG ( or other equivalent means of ischemia induction). This is because clinical studies have shown us ( unequivocally ) that the are many stenosis that do not actually cause problems. Such stenosis can be dealt with, with optimal medical therapy. Assymptomatic, non-ischemia producing stenosis do just as well with optimal medical therapy as with angioplasty.
Once, the clinician is satisfied that the patient myocardial ischemia, uncontrolled by medical therapy, then a coronary angiogram is indicated. The coronary angiogram is an accurate ( although not infallible ) way of diagnosing coronary artery disease. It tells us the anatomy, the probable culprit lesion, and also the prognosis. Taken together, it allows us to draw-up a medical strategy for the patient, indicating what is the best thing to do for good short, intermediate and longterm outcome. Often, a coronary angiogram may lead on to an ad-hoc ( at the same sitting) angioplasty, or less often nowadays, a coronary angiogram may lead to cornary artery bypass surgery ( CABG ).
These will form the basis of another blog.
I just wish to emphasize today, that there are certain indications for a coronary angiogram, as it is expensive and does carry a risk ( albeit a small risk ). Inducible ischemia, either in the form of symptoms ( chest pains ), or positive stress ECG, stress echo or stress radionuclide scans.