Detecting Atherosclerosis
Detecting Atherosclerosis
When abnormal build-up (plaquing) occurs in any artery, we label that atherosclerosis. When your body and immune system attempts to heal the blood-flow disruption that occurs, calcific plaques develop as an evolution of this aging process. We call this arteriosclerosis, “hardening of the arteries”. These calcified plaques can be measured in the most vulnerable and predictive arterial bed, the coronary arteries.
Although Atherosclerotic Cardiovascular Disease (ASCVD) can occur in any artery, the coronary arteries have proven to be the “canary in the coal mine” of ASCVD. The test for measuring calcific plaquing of the coronary arteries, coronary artery disease (CAD), also known as coronary heart disease (CHD) is known as the Coronary Artery Calcium (CAC) score. This test has been my most useful diagnostic test for over 30 years now.
This classic picture shows a timeline of atherosclerosis, and the related condition, endothelial dysfunction (ED, the real ED, strongly associated with the “other ED” - Erectile Dysfunction!). So, yes humanity, everyone knows that “soft plaques” preceding calcific ASCVD are missed by the CAC as ASCVD is a multi-decade process far more complicated than cholesterol levels.
What we also know is that a CAC of zero excludes the possibility of a cardiovascular event and excludes the possibility of requiring treatment for cholesterol, with a statin or any other medicine or supplement.
For an excellent article go to PMID 28847895, ‘The Prognostic Value of the Coronary Artery Calcium Score in the PROMISE study'.
The CAC has remarkably low radiation exposure, the equivalent of less than 2 chest x-rays, takes just the equivalent of two breath-holds to accomplish, and only costs between $50-$150. This test outperforms any other vascular measurements at predicting cardiovascular events, cardiovascular mortality and all-cause mortality and has nearly 40 years of research.
As mentioned in our LDL article, we screen every man at age 45, every woman at age 55, and screen earlier in people with family history or risk factors. Follow-up testing depends on the original score.
A CAC of 0: perfect. 1-10 is insignificant CAD but consider an earlier re-test, 11-100: mild CAD, 101-400: moderate CAD, 401-1000: severe CAD, and >1000: very severe CAD.
The risk stratification provided by the CAC outperforms even the traditional functional test, the stress echo or stress myocardial perfusion test. I only refer for stress testing to evaluate symptoms and not based on any absolute CAC score. The CAC looks at total plaque burden and reports your score relative to other people your age and sex. It is not intended to predict the percent blockage of an artery.
The stress echo or stress myocardial perfusion test looks to see if the heart can maintain blood flow with exercise (or a medicine is infused to increase heart rate). If one suspects critical CAD, see a cardiologist for this test. If one wants to see if they are developing any CAD at all, that’s a much different question. You can have significant plaque burden and still pass a functional test.
One day soon AI enhanced CAC testing will also be routinely available to more accurately predict actual degrees of blockage, and dramatically reduce the need for “screening" functional testing.
Once we diagnose CAD, we proceed to treatment, the subject of our next article!
Your Journey to Health & Healing,
Gary E Foresman MD