The strongest prognostic diagnostic marker of coronary heart disease is the Coronary Calcium Score (CCS)
It is an easy and fast examination thanks to the new technology CT-scanners (EBCT-electron beam scanner). Since 2016, this examination is recommended by the guidelines of the European Society of Cardiology. Since 2017, it has been established as presymptomatic - preventive testing every five years, such as mammography and colonoscopy.
Until now, the detection of patients with Coronary heart disease was mainly based on various scores which had been defined by studies (the most known of them is the Framingham SCORE, FRS). By data more than 300 predisposing risk factors that cause coronary heart disease have been identified until today. The most important of them are included in a list known as Framingham score and are the following: age, gender, total cholesterol, HDL (good cholesterol), smoking, diabetes mellitus, arterial hypertension. The basic problem with these prognostic models that are based on the classic predisposing risk factors (CPRF) is that they explain only 50% to 60% of cardiovascular events. A consequence of this is that many high-risk patients do not benefit from a strategy of preventive treatment. The Calcium score, that is the detection of calcifications in the coronary arteries with the use of a CT-scanner, allows in the most reliable and non invasive way to detect at an early stage, the existence or non existence of coronary heart disease, before the manifestation of clinical symptoms of coronary heart disease. It is an easy, painless examination, that lasts only a few seconds without the use of contrast agent, with a minimal amount of radiation. The CCS calcification rate of the coronary arteries, is by itself the strongest prognostic indicator of future events compared to all the other risk factors. The quantification of calcifications of the coronary arteries predicts heart events in asymptomatic middle-aged patients of a moderate risk and not only in them. It is the deposition of calcifications on the tunica intima of coronary arteries. They are radiopaque (that is, they are not penetrated by X-rays) and their detection is possible with last generation CT-scanners without any injection of a contrast agent (Figure 1).
Figure 1 These calcifications are directly associated with the risk of cardiac events. People with a high rate of calcifications have a higher atheromatous load and a higher risk of cardiac events regardless if there are any symptoms or not. Regarding soft consistency damages that may exist and cannot be ruled out by the simple examination for the detection of coronary calcification lesions, a large number of studies have shown that if there is a calcium score less than 11, this is associated with a minor rate of occurrence of cardiac events.
Depending on the calcium score we classify the patients:
1st group: Absence of calcifications in the coronary arteries (calcium score = 0) which is associated with a very low possibility of coronary disease (<1%).
2nd group: Calcium score of 1-80. In this group the possibility of occurrence of symptomatic cardiovascular disease is 2 to 5 times higher than in the patients with no calcifications. (3:1)
3rd group: Calcium score 80-400. In this group the risk of occurrence of coronary heart disease is 12 to 16 times higher than in the patients with no calcifications (12-16:1)
4th group: Calcium score over 400. In this case the risk is 25 times higher (22-28:1). In this group 90% of the patients will have at least an important lesion in the coronary arteries.
This examination should be repeated every 1-5 years depending on the results.
Contraindications
Pregnant women should not undergo this test, due to the radiation, although it is minor.
Practically
⦁The first important message is that the presence of calcifications is synonymous with atherosclerosis of coronary arteries. The calcifications are part of the development process of atherosclerosis. It is particularly rare in people under 30 years of age, and it is not recommended to look for calcifications in young patients with no other risk factors. Moreover, after 70 years of age more than 95% of men and 75% of women present calcifications in the coronary arteries.
⦁ A second important message is that although the Coronary calcium score - CCS offers a quantitative assessment of the extent of the coronary atherosclerosis, it does not give us any information about the severity or not of a possible stenosis of the coronary network. However, in people with a calcium score (CCS) higher than 400, there is a high chance (>90%) that there is a serious stenosis in one artery at least (>70%). Thus, in cases with a CCS that is higher than 400, further control is required. The CCS is an anatomic test for the overall atheromatous load, and is a supplementary examination to other dynamic tests that control the functional capacity and sufficiency of the coronary network.
Furthermore, the important negative prognostic value of this examination, can be used in order to rule out the diagnosis of unstable angina pectoris, in patients with chest pain and an ECG that does not help in the diagnosis. In these patients that have a CCS of 0, the negative prognostic value of approximately 100% allows for the exclusion of the diagnosis of angina, and therefore these patients do not undergo further examinations.
For this reason, the latest European guidelines recommend finding out what the patients’ CCS (coronary calcium score) is with the use of last generation CT-scanners, particularly in patients of medium risk as well as in patients with Diabetes mellitus. From this year, it has been introduced in the USA as a preventive medical screening test for the entire population, such as mammography, colonoscopy, low dose CT-scan in heavy smokers. With CT-scanners such as Somatom Definition Flash the diagnostic center Asklipios Diagnosis has, the detection and quantification even of the minor calcifications of coronary arteries is allowed. The final product of this examination is the total of the calcifications of the coronary network.
Fanis Zambetakis,
Cardiologist, Scientific Director of Asklipios Diagnosis, Specialized in Invasive Cardiology and in Cardiovascular Imaging in France.
Assistant Professor at the University of Strasbourg,
Head of the department of cardiovascular imaging of the diagnostic center Asklipios Diagnosis