From the Guidelines
For individuals with a coronary calcium score of 0, retesting is generally recommended every 5 years, as suggested by the most recent guidelines from the National Lipid Association (NLA) 1. This interval is appropriate because a score of 0 indicates no detectable calcified plaque in the coronary arteries and represents very low cardiovascular risk. The progression of coronary artery calcification typically occurs slowly in those starting with a zero score, making more frequent testing unnecessary. However, this recommendation may be modified based on individual risk factors such as family history of premature coronary artery disease, diabetes, smoking, hypertension, or high cholesterol. Some guidelines, such as those from the NLA, suggest that borderline- to intermediate-risk patients (5%-19.9% 10-year risk) warrant repeat scanning at 3 to 5 years, while high-risk or diabetes patients warrant repeat scanning at 3 years 1. Patients with multiple risk factors might benefit from earlier retesting, perhaps at 3-4 year intervals. The purpose of retesting is to monitor for the development of calcified plaque, which would indicate progression of atherosclerosis and might warrant more aggressive preventive measures including lifestyle modifications and possibly medication therapy. Despite having a zero calcium score, it remains important to continue heart-healthy behaviors including regular exercise, healthy diet, and management of any existing cardiovascular risk factors. Key considerations for retesting intervals include the patient's baseline estimated ASCVD risk, with the NLA advocating for repeat scanning intervals of 5 to 7 years for low-risk patients, 3 to 5 years for borderline- to intermediate-risk patients, and 3 years for high-risk or diabetes patients 1. The Society of Cardiovascular Computed Tomography (SCCT) also recommends repeat scanning every 5 years when CAC = 0 and every 3 to 5 years when CAC >0 1. Ultimately, the decision to retest should be individualized based on the patient's unique risk profile and clinical presentation.
From the Research
Coronary Artery Calcium (CAC) Score Retesting Interval
The recommended interval to retest Coronary Artery Calcium (CAC) score in a patient with a score of 0 is:
- 5 years, as stated in the Cardiac Society of Australia and New Zealand Position Statement: Coronary Artery Calcium Scoring 2
- 5 to 10 years, as suggested by the JCL roundtable: Coronary artery calcium scoring and other vascular imaging for risk assessment 3
- Not less than 4 to 5 years, as mentioned in the study CT coronary calcification: What does a score of "0" mean? 4
Key Points
- A CAC score of 0 confers a very low risk of death, <1% at 10 years 2
- The absence of detectable calcification determines excellent cardiovascular prognosis, with event rates lower than that of negative stress studies 4
- Negative results of atherosclerosis-imaging tests, particularly coronary artery calcium score of 0, resulted in the greatest downward shift in estimated CVD risk 5
- Combining information from the CAC score with information from conventional risk factors can change assessment of coronary heart disease risk to an extent that may be clinically important, especially when the pre-test 10-year risk estimate is intermediate 6