What is a coronary artery calcium (CAC) test?

My husband is a really healthy 53-year-old long-distance runner who runs not only to remain fit, but in addition to avoid having to take antihypertensive medications, which he was off of over a decade ago. In addition to his personal history of hypertension, he had a family history of hypercholesterolemia. At the last annual check-up, the triglyceride level was 49 mg/dl (normal is lower than 150 mg/dl), the overall cholesterol was 179 mg/dl (lower than 200 mg/dl is desirable), the low-density lipoprotein (LDL) was 105 mg/dl dl (lower than 100 mg/dl is perfect), high-density lipoprotein (HDL) was 60 mg/dl (greater than or equal to 60 mg/dl is desirable); and his total cholesterol to HDL-C ratio was 3 (lower than 5 is normal, lower than 3.5 is extremely desirable). Although these results were generally superb, resulting from his elevated LDL levels of cholesterol, his primary care physician beneficial a coronary artery calcium (CAC) test to find out whether he needs to be prescribed a statin (a cholesterol-lowering drug). My husband quickly signed up for the test, and after receiving the outcomes, he proudly announced: “I have coronary artery disease for a 30-year-old!” Fortunately, statins won’t be needed presently, my blood pressure might be under control, and my husband can have many more years of running ahead of him. Although I used to be overjoyed by the news, I had never heard in regards to the CAC result and wondered, “Should I order this test too?”

Assessment of coronary artery calcium (CAC).

The CAC rating measures the presence of calcifications within the coronary artery in the center. CAC begins as microscopic spots that grow to be large deposits of plaque, normally within the inner layer of a coronary artery. The CAC rating indicates the severity of atherosclerotic heart problems (ASCVD), and the outcomes will help guide treatment selections akin to statin therapy and lifestyle modifications (Kramer and Villines, 2022). The CAC rating has been found to be a stronger predictor of cardiac risk than most other serum biomarkers.

The CAC rating (also referred to as CT-calcium) is obtained using computed tomography (CT) and is frequently measured by the Agatston method, which calculates the world and density of calcified plaque. CAC scores are reported each as a patient’s total rating and as a rating for every individual coronary artery (Orringer, 2020). We will give attention to the overall variety of CAC points, which will be divided as follows (Kramer and Villines, 2022):

• 0 Agatston units = No identifiable disease
• 1 to 99 Agatston units = mild disease
• 100 to 399 Agatston units = moderate disease
• 400 or more Agatston units = severe disease

The rating is then in comparison with those of patients of comparable age, gender and ethnicity to acquire a percentile. This is achieved using the Multi-Ethnic Study of Atherosclerosis (MESA) calculator used for people aged 45 to 84 who would not have diabetes or known heart problems (CVD). The absolute CAC rating provides a sign of short-term risk (5–10 years of ASCVD), while the CAC percentile rating provides the most effective approximation of the relative risks and advantages of treatment over a lifetime (Orringer, 2020).

CAC screening is helpful in the next people (Kramer and Villines, 2022):

• Asymptomatic adults over age 40 at moderate to high risk (7.5 to lower than 20 percent risk of ASCVD over 10 years) as assessed by the American College of Cardiology/American Heart Association (ACC/AHA) risk calculators
  • Among asymptomatic patients, the CAC rating helps predict ASCVD and mortality, especially for patients at borderline and intermediate risk (10-year ASCVD risk ranges from 5 to twenty percent).

• Patients at borderline increased risk of ASCVD (5 to 7.4 percent risk of ASCVD over 10 years) who’ve a family history of premature ASCVD

CAC testing just isn’t helpful in the next patients (Oringer, 2020):

• People at low (lower than 5 percent risk over 10 years) or very high (20 percent or more risk over 10 years) risk of ASCVD, as the outcomes are unlikely to vary treatment strategy
• People with clinical ASCVD, including acute coronary syndrome, history of acute myocardial infarction, stable or unstable angina or coronary or other artery revascularization, stroke, transient ischemic attack, or peripheral arterial disease including aortic aneurysm
• As a primary diagnostic tool in individuals with symptoms of myocardial ischemia (angina or shortness of breath) because CAC alone is less predictive of coronary artery disease
  • However, CAC could also be performed along side CT angiography to offer additional information.

Advantages of CAC tests (Orringer et al., 2020)

CAC imaging has several benefits over invasive coronary angiography.

• Minimal or no patient preparation is required. Patients don’t need an intravenous (IV) catheter, arterial line, beta-blockers, or nitroglycerin.
• Iodine contrast just isn’t used.
• Before the procedure, the patient doesn’t must fast or take any medications.
• A fast and effective CAC test will be obtained on any CT scanner that supports ECG gating, which collects data during a particular phase of the cardiac cycle.
• There is a low dose of radiation; CAC scans use a radiation dose comparable to screening mammography.

Management (Kramer and Villins, 2022)

Generally, all patients are advised to make lifestyle changes akin to eating a healthy eating regimen, stopping smoking and exercising frequently. It just isn’t beneficial to repeat the CAC test to evaluate the effectiveness of lifestyle changes.

• CAC rating greater than or equal to 100 (or 75% for age, sex, and race): A statin is beneficial if low-density lipoprotein cholesterol (LDL-C) is 100 to 190 mg/dl.
• CAC rating from 1 to 99 (or lower than 75^vol percentile for age, gender, and race): physicians should discuss statin therapy with the patient. The good thing about statins could also be modest in these patients.
• CAC rating of 0 and no other risk aspects: patients have a low 10-year risk of ASCVD, due to this fact treatment with statins or aspirin just isn’t beneficial. After five years, risk stratification needs to be re-stratified. A CAC rating of 0 is the strongest “negative risk marker” for ASCVD.

CAC Score Summary (Campbell et al., 2024)

Please note that CAC scans will not be covered by insurance. However, it serves as a further tool that gives useful details about ASCVD risk and helps healthcare providers and their patients make essential decisions regarding risk reduction and treatment strategies. At my next annual visit, I’ll discuss CAC testing with my primary care physician, and I now feel higher informed to discuss this kind of screening with my patients, family and friends.

What is your experience with CAC testing? Please share within the comments below.

Campbell, K., Harber, A., Jennings, J., & Smiley, L. (2024). Calcium level testing on computed tomography for early detection of coronary artery disease. , (2), 6–9. https://doi.org/10.1097/01.NPR.0000000000000140

Kramer, C. M. and Villins, Connecticut (2022). Coronary artery calcium (CAC) assessment: review and clinical application. . https://www.uptodate.com/contents/coronary-artery-calcium-scoring-cac-overview-and-clinical-utilization

Orringer, C. E., Blaha, M. J., Blankstein, R., Budoff, M. J., Goldberg, R. B., Gill, E. A., Maki, K. C., Mehta, L., & Jacobson, T. A. (2021). National Lipid Association scientific statement on coronary artery calcium assessment to guide preventive strategies to cut back the chance of ASCVD. , (1), 33–60. https://doi.org/10.1016/j.jacl.2020.12.005