How Do I Choose Between a Cardiac Cath and a CT Coronary Angiogram (CTCA)?
The decision between a Cardiac Cath and a CT Coronary Angiogram (CTCA) is complex.
Both investigations require x-rays and x-ray dye.
Invasive Coronary Angiogram
A Cardiac Cath provides better resolution of the blood passage down the artery (lumen) even with faster heart rates, but can be limited in areas of vessel branching where sub-branches can obscure each other where they overlap. Other advanced diagnostic techniques may be used at the time of Cardiac Cath, such as FFR, IVUS or OCT to clarify the significance of stenoses. There is a small risk of serious complications in passing the tube to the coronary artery.
An additional benefit is the option to immediately proceed to a therapeutic intervention such as insertion of a stent to relieve a blockage at the time of invasive angiography. This is frequently life-saving in the setting of an ST-elevation myocardial Infarction. (STEMI).
CT Coronary Angiogram (CTCA)
The CTCA provides more information about the wall of the arteries, however, it is limited in the presence of calcium which blocks the x-rays and so may not be definitive. An “uninterpretable” region of the vessel may be reported.
A CTCA has less resolution of the coronary artery and image quality is dependent upon a slow heart rate to avoid blurring. This can be a problem for anxious patients, even with premedication with beta-blockers.
A CTCA is only diagnostic as it does not provide the opportunity for immediate intervention.