CT calcium scoring

Coronary artery calcium (CAC) is a sensitive marker of coronary artery atherosclerosis

• CAC can be detected and qualified with electron beam CT (EBCT) and multislice CT (MSCT)
• NICE have stated that:
  • for people with chest pain in whom stable angina cannot be diagnosed or excluded by clinical assessment alone and who have an estimated likelihood of coronary artery disease (CAD) of 10-29% offer CT calcium scoring. If the calcium score is:
    • zero, consider other causes of chest pain
    • 1-400, offer 64-slice (or above) CT coronary angiography
    • greater than 400, offer invasive coronary angiography. If this is not clinically appropriate or acceptable to the person and revascularisation is not being considered, offer non-invasive functional imaging
• Table 1: Non-anginal chest pain - % likelihood of CAD

Table 1 represents people with symptoms of non-anginal chest pain, who would not be investigated for stable angina routinely

Table 2: Atypical anginal pain - % likelihood of CAD

Table 3: Typical angina - % likelihood of CAD

• for men older than 70 with atypical or typical symptoms, assume an estimate > 90%.
• For women older than 70, assume an estimate of 61-90% EXCEPT women at high risk AND with typical symptoms where a risk of > 90% should be assumed
• Values are per cent of people at each mid-decade age with significant coronary artery disease (CAD)
• Hi = High risk = diabetes, smoking and hyperlipidaemia (total cholesterol > 6.47 mmol/litre)
• Lo = Low risk = none of these three
• Note:
  • These results are likely to overestimate CAD in primary care populations. If there are resting ECG ST-T changes or Q waves, the likelihood of CAD is higher in each cell of the table.

Reference:

• 1) NICE (March 2010). Chest pain of recent onset.