CORONARY CT ANGIOGRAPHY FOR HEART DISEASE
Any condition that affects the function of the heart is considered heart disease. Coronary artery disease (CAD) is the most common kind of heart disease and causes most heart attacks and chest pain (angina).
Over time, conditions like high blood pressure, abnormal cholesterol levels, cigarette smoking, and diabetes can begin to damage the smooth interior surface of arteries. When this happens to blood vessels throughout the body it's called vascular disease. When it affects the arteries that carry blood to the heart muscle, it’s called coronary artery disease.
As the damage to artery walls continues, "bad" cholesterol can start to build up. White blood cells and other cells are then sent to the area to help clean up the cholesterol. Over time, plaque buildup (composed of fat, cholesterol, or calcium) can narrow the arteries and reduce blood flow. This is often called hardening of the arteries or atherosclerosis.
For those at risk of CAD, screening exams are very important. Screening tests help determine the amount of plaque, its nature (hard or soft), and what treatment options are applicable.
WHAT ARE THE BENEFITS OF HEART SCREENING EXAMS?
To help diagnose CAD, patients are usually referred for one of two main screening exams: a coronary angiography or a coronary computed tomography angiography (CCTA).
- During a coronary angiography, a thin, hollow tube called a catheter is inserted into an artery (usually in the arm or leg) and threaded up into the heart. A contrast dye is then sent through the catheter to help the arteries show up on an X-ray.
- For a CCTA, computed tomography (CT) is used to non-invasively examine the coronary arteries. CT imaging uses a combination of X-rays and computer technology to produce comprehensive, detailed images. In particular, CCTA detects both hard and the more difficult to find soft plaques, which may be more likely to cause heart attacks and death. This exam also uses imaging contrast, but it’s injected through a vein in the arm and pictures of the arteries are taken from outside the body.
Patients with family histories of heart disease may be at risk for developing atherosclerotic plaque buildup, blocking or narrowing coronary arteries. On CT, these can be identified even before symptoms of chest pain develop.
WHAT ARE THE RISKS OF HEART SCREENING EXAMS?
A coronary angiography is an invasive procedure, which in rare cases can lead to serious problems like heart attack or stroke. There is also a risk of a tear or sudden closure in an artery, allergic reaction to the dye, and bleeding or bruising where the catheter was inserted. It also requires fasting before the procedure and hours of hospitalized recuperation afterward. Plus, there is potential for overuse when diagnosing patients with atypical symptoms and low-to-medium risk of disease.
CCTA also has the possibility of an allergic reaction to the contrast dye. As well, certain patients may not be good candidates for this exam, such as:
- Patients over 450 pounds who may not fit into the machine.
- Patients with irregular or fast heart rhythms who are unable to take medication to slow their heart rate, since CCTA requires a slow, regular heart rate for accurate images.
- Patients who are not able to lie flat, follow voice instructions, or hold their breath for up to 20 seconds.
- Patients with many areas of old, hardened plaque, which is often the case in older patients.
WHICH EXAM WOULD I NEED?
Studies have shown that the diagnostic abilities of CCTA versus coronary angiography are equivalent. Due to lower costs and improved safety, CCTA is thought to be a better first-line test to triage patients and determine the need for medical therapy or invasive evaluation. Plus, current CT scanners have lower doses of radiation and improved accuracy as compared to older machinery, and patients often prefer CCTA for coronary disease testing since it’s less invasive.
Your doctor might recommend CCTA screening if you have a family history of heart disease or to investigate symptoms such as chest pain or shortness of breath.
When looking for the cause of chest pain, other types of medical imaging may also be ordered to assess heart function, electrical changes within the heart, or blood flow to and from the heart (exercise stress testing, myocardial perfusion imaging).
HOW DO I GET CCTA?
Coronary CT angiography is available as a private pay exam, not covered by Alberta Health Care, at our Mayfair Place location. It can be purchased on its own or as part of a Health Assessment package, which provides a discount on multiple imaging exams when purchased together.
Your health spending account or group medical insurance plan may cover the cost of a private CT that is prescribed by a qualified health care practitioner. You will need to check with your plan administrator for coverage details.
Whether public or private, medical imaging must be requested by a health care practitioner who will provide a requisition. Your medical and family history, risk factors, and type and duration of symptoms, all affect a referring physician’s decision on which type of imaging is appropriate.
When we receive your requisition Mayfair Diagnostics will schedule your exam and provide you with detailed information to prepare for it. Once your exam is completed, your images will be reviewed by a specialized radiologist who will compile a report that is sent to your doctor.
Barnes, Eric (2016) “Is it time for CCTA to replace invasive angiography?” www.auntminnie.com. Accessed August 30, 2021.
Doh, J. H., et al. (2014) “Diagnostic value of coronary CT angiography in comparison with invasive coronary angiography and intravascular ultrasound in patients with intermediate coronary artery stenosis: results from the prospective multi-centre FIGURE-OUT (Functional Imaging criteria for GUiding REview of invasive coronary angiOgraphy, intravascular Ultrasound, and coronary computed Tomographic angiography) study.” European Heart Journal Cardiovascular Imaging. August, 15(8): 870-7