Dr Caitlin: Coronary Artery Calcification Tests

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rsz_dr_caitlin_oconnorDr Caitlin O’Connor of Tralee Medical Centre in St Brendan’s Park, on measuring calcium in coronary arteries…

Coronary artery disease (CAD) is still a leading cause of morbidity and mortality in Europe. There has been much interest in developing screening methods to identify those at risk of having a primary cardiac event.

What is coronary artery calcium (CAC)?

The presence of calcium in coronary arteries is almost always indicative of atherosclerotic plaque (but bears no relationship to plaque stability or instability). Cardiac risk factors and insulin resistance lead to progression of coronary artery calcification.e a reflective diary.

Continued below…

John Ross Jewellers

How do we measure the coronary artery calcium score (CACS)?

CACS is determined by CT scanning which is non-invasive and can be of two types:

• Electron beam CT scan (EBCT).

• Multidetector CT scan (MDCT).

EBCT is the most common technology currently used to measure CACS.

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Coronary artery calcium scanning is not useful in those at very low or very high risk, or in those with known coronary artery disease (CAD).

It is unclear at present as to who should be offered coronary artery calcium (CAC) scanning but the following are possibilities:

Screening asymptomatic patients.

Screening those with intermediate risk of coronary artery disease.

Presence of just one risk factor, eg mild hypertension. Note that diabetic patients and those with chronic kidney disease (CKD) will probably have high calcium scores which may not necessarily represent significant clinical coronary atherosclerosis.

Presence of a strong family history of premature CAD.

The main disadvantages of CACS are its lack of information regarding a patient’s functional capacity (which could be inferred from an exercise tolerance test (ETT)) and lack of data in ethnic groups.

It has been argued that a CACS over 100 indicates the presence of atherosclerosis and, unless there is a clinical indication, the treatment is lifestyle modification.

The main benefit of CACS is its high negative predictive value, reported as high as 98% in some studies.

What does the evidence tell us about the coronary artery calcium score?

Some evidence suggests that increased CACS predicts subsequent development of heart disease. However, prospective studies are lacking and there are also some data suggesting that CACS does not add anything over and above other scoring systems.
Future considerations

Further evidence and guidance is required to determine how to use CAC scans effectively and the role they play amongst other cardiac investigations.

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