Coronary Artery Calcium Scoring Gets American Heart Association Endorsement
At the annual American Heart Association convention, on November 10, 2018 [and simultaneously published in their Scientific Journal] the much-anticipated update to the 2013 Guideline for Management of Blood Cholesterol, was presented to a standing room only audience.
Since 1980 the two major cardiology societies have tried to translate scientific evidence into clinical practice guidelines with recommendations to improve cardiovascular health. Initially these were only lifestyle suggestions but after the first studies published in the early 1990’s regarding the use of ‘statin’ cholesterol-lowering medications which could dramatically lower an individual’s cholesterol levels – the guidelines have, initially cautiously but now whole-heartedly supported the aggressive use of various statin medications to a variety of cholesterol goals. The clinical application of these goals consisted of first assessing the ‘risk’ of the patient using the Framingham Risk Equations [which incorporated information about cholesterol, smoking habits, age, gender, diabetes, and blood pressure]. After a simple calculation made my any physician, he/she would be advised that their patient was ‘low’ risk, ‘high’ risk, or ‘intermediate’ risk for the future development of heart disease – and the individual cholesterol ‘goal’ was then indicated in the guidelines. There had always been controversy about the accuracy of the ‘intermediate’ designation [which unfortunately may be up to 50% of a standard internists or family practitioners waiting room].
The History Behind Using Coronary Artery Calcium Scoring to Define Cardiac Risk
In 2013 there was a dramatic change in the method of defining the patient risk using what is called ‘the pooled cohort equations’ which purported to refine the actual risk category and thus make it more judicious who should or should not be started on a statin for their cholesterol value. However, these recommendations were generally not well received by all – suggesting that the newer risk calculation was giving TOO HIGH a value than reality. The focus of the confusion however has not necessarily who was ‘low’ or ‘high’ risk – but were the intermediate risk group truly ‘in-between’.
Coronary artery calcification [CAC] measurements using non-contrast CT has been used clinically by select practitioners for the past nearly 30 years. In fact, I made this one of my own personal research subjects during my time at the Mayo Clinic and, along with colleagues, wrote the first ‘Guidelines for the Use of Coronary Artery Calcium in Clinical Practice’ in 1998!
Research on CAC has now been done in literally hundreds of thousands of patients in all major medical centers across the world. The research has show four major findings: 1) when the CAC score is zero your PERSONAL cardiac risk is <0.1%/year, and thus VERY LOW; 2) the higher the CAC score, the higher your personal risk; 3) that the application of CAC scoring to the ‘intermediate’ risk patients can result in re-assigning [to ‘low’ or ‘high’] the actual cardiac risk in 50% of the patients; and 4) the decision on who should get or does not need statins can be based on the CAC score.
The cholesterol guidelines had commented on CAC scoring in the past but had never actually suggested this as an alternative to define actual risk in the large ‘intermediate’ group.
New Guideline Changes Include Coronary Artery Calcium Scoring in Determining Use of Statin Treatment
The way risk in the large “intermediate” group was defined all changed in the past few days. The 2018 Guidelines now include the use of CAC as a decision maker, especially in the ‘intermediate’ risk group; the group in which an individual’s risk level isn’t clear and treatment decisions are less certain. Furthermore, the new Guidelines indicate that a CAC score of zero typically indicates a low risk for cardiovascular disease and could mean those people can forego or at least delay cholesterol-lowering prescriptions. They further go on to indicate that the CAC scan should be done by a qualified provider in a facility offering the most current technology.
Below is a graphical summary of the use of statins and use of CAC.
Princeton Longevity Center at all three Facilities applaud the 2018 Guidelines for Management of Blood Cholesterol and for incorporating and supporting use of non-invasive quantification of sub-clinical coronary atherosclerosis using Cardiac CT.